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Full text of "Applied anatomy;"

UNIVERSITY OF CALIFORNIA 

MEDICAL CENTER LIBRARY 

SAN FRANCISCO 




Gift of 
Samuel Mern'tt Hospital 



n 



I 



I 



Digitized by the Internet Archive 

in 2007 with funding from 

IVIicrosoft Corporation 



http://www.archive.org/details/appliedanatomyOOdavirich 



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APPLIED ANATOMY 



THE CONSTRUCTION OF THE HUMAN BODY 

CONSIDERED IN 

RELATION TO ITS FUNCTIONS, 
DISEASES AND INJURIES 



BY 

GWILYM G. DAVIS 

M.D., UNIVERSITY OF PENNSYLVANIA AND GOETTINGEN ; M.R.C.S., ENG. ; LL.D., LAFAYETTE 

"professor of ORTilOPEDIC SURGERY AND FORMERLY ASSOCIATE PROFESSOR OF APPLIED ANATOMY IN THE UNI- 
VERSITY OF PENNSYLVANIA ; CONSULTING SURGEON TO ST. JOSEPH'S HOSPITAL ; FORMERLY SURGEON 
TO THE EPISCOPAL HOSPITAL ; SURGEON TO THE ORTHOPEDIC HOSPITAL ; ORTHOPEDIC SURGEON 
TO THE UNIVERSITY AND PHILADELPHIA GENERAL HOSPITALS ; FELLOW OF THE AMERI- 
CAN SURGICAL ASSOCIATION, THE PHILADELPHIA ACADEMY OF SURGERY AND 
PHILADELPHIA COLLEGE OF PHYSICIANS ; MEMBER OF THE AMERICAN 
SOCIETY OF CLINICAL SURGERY, THE AMERICAN ORTHOPEDIC 
ASSOCIATION, AMERICAN ACADEMY OF MEDICINE, ETC. 



WITH SIX HUNDRED AND THIRTY-ONE ILLUSTRATIONS, MOSTLY 
FROM ORIGINAL DISSECTIONS AND MANY IN COLOR 

BY 

ERWIN F. FABER 






FOURTH EDITION 




PHILADELPHIA & LONDON 

J. B. LIPPINCOTT COMPANY 



1S5708 



Copyright, 1910 
By J. B. LippiNCOTT Company 



Copyright, 1913 
By J. B. LippiNCOTT Company 



Copyright, 191 5 
By J. B. LippiNCOTT Company 



Copyright, 1916 
By J, B. LippiNCOTT Company 



Printed by J. B. Lippincott Company 
The Washi?tgtott Square Press, Philadelphia, U. S. A 



To 
GEORGE A. PIERSOL, M.D., Sc.D. 

PROFESSOR OF ANATOMY IN THE UNIVERSITY OF PENNSYLVANIA, 
AN IDEAL SCIENTIST, TEACHER, AND FRIEND 



PREFACE TO FOURTH EDITION. 



In this edition there have been a few corrections to the cuts and text and 

some new matter added. 

The Author. 
1814 Spruce Street, April, 1916. 



PREFACE TO SECOND EDITION. 



In this edition the general plan of the work has been retained. The 
text and illustrations have been carefully revised with many corrections and 
additions. The cuts have been made more accurate, ten have been entirely 
replaced and two new ones added. Our thanks are extended to our kindly 
critics who have aided us in making the book more accurate and useful. 



The Author. 



1814 Spruce Street, January, 1913. 



PREFACE TO THE FIRST EDITION. 



It is not the object of this work to teach plain anatomical facts ; its aim is to 
show the relation of structure to function, whether it is normal function or function 
disturbed or impaired by injury or disease. It is explanatory and utilitarian in 
character, and not encyclopedic. The bare facts of anatomy can be obtained from 
the systematic treatises, and they are here only briefly given in order to refresh the 
memory of the reader, who is supposed to be familiar to a certain extent with 
systematic anatomy. A person who has studied the subject only from a systematic 
standpoint cannot utilize and apply the knowledge so acquired unless he considers 
its relation to the various affections encountered in practice. He can study anatomy, 
but he will not see its application until it is pointed out to him. He may have 
studied the palmar fascia, but, unless he is shown how its construction influences the 
course of pus originatmg beneath it, his anatomical knowledge is of little value. 
The inability to make any practical use of the facts or to see their application is the 
reason why anatomy is so frequently regarded as a dry, uninteresting study and too 
often designedly neglected. 

In considering the subject, after a few general remarks on the part involved, the 
skeleton and muscles are briefly described, and thereby one is enabled to understand 
the surface anatomy, which immediately follows. Then comes a consideration of the 
various affections of the part, with such allusion to the nerves and vessels as is desir- 
able to elucidate the subject. As the book is not intended to be a systematic 
treatise on anatomy, such anatomical facts as cannot be shown to be useful in practice 
are not mentioned. To give them here would make the volume too large, obscure 
its main object, and defeat its purpose. 

As regards the anatomical nomenclature used, there is no system so generally 
accepted as to justify its exclusive adoption. In the desire, however, to aid in further- 
ing the adoption of better anatomical terms, as much of the BNA terminology has 
been used, or included in parentheses, as a consideration of the subject from the 
standpoint of a general practitioner would allow. 

Most of the illustrations are from original drawings of preparations made by the 
author and his assistants. Those derived from other sources are duly credited ; if 
there has been any failure in this respect, it is unintentional. 

The clinical material, except where otherwise stated, is from the author's own 
experience. 

To the artist in charge, Mr. Erwin F. Faber, and to Mr. Herman Faber, who 
made a large number of the original sketches, my best thanks are due for their great 
skill, untiring energy, and most intelligent aid ; their work speaks for itself. 



vi PREFACE. 

I am under great obligations to many friends who have kindly rendered me their 
aid. Professor George A. Piersol has given me much valuable information and 
allowed me the unstinted use of his anatomical material ; Dr. Astley P. C. Ashhurst 
made many of the dissections and aided in correcting and preparing the manuscript 
for the press ; Dr. Frank D. Dickson did most of the proof-reading and prepared the 
index ; Dr. T. Turner Thomas made many of the earlier preparations ; and Dr. Henry 
Beates aided in the revision of the first portion of the manuscript. To these and 
others who have contributed to the formation of the book I desire to express my 
thanks. 

To the hearty cooperation and unfailing generosity of my publishers is due the 
presentation of such an attractive volume. I asked them for nearly everything I 
could think of, and they gave me nearly everything I asked for. 

In conclusion : this work is recognized as being far from complete, but it is 
intended to be suggestive rather than absolute. It is not designed so much to 
present facts as to furnish reasons, and it is hoped that it will appeal to the practising 
physician and surgeon as well as to the student. 

GwiLYM G. Davis. 
Philadelphia, August, 1910. 



CONTENTS. 



THE SCALP. Page 

Skin I 

Superficial Fascia i 

Occipitofrontalis Muscle 2 

Subaponeurotic Tissue 2 

Pericranium 2 

Subpericranial Tissue 2 

Arteries of the Scalp 3 

Temporal Artery 3 

Occipital Artery 3 

Lymphatics of the Scalp 4 

Affections of the Layers of the Scalp. ... 4 

Affections of the Blood-vessels 6 

Treatment of Vascular Aft'ections of the 

Scalp 7 

Tumors of the Scalp 7 

THE SKULL. 

The Skull in Childhood 8 

Fontanelles 8 

Dura Mater g 

The Skull in Adults 10 

Tables 10 

Sutures 10 

Frontal Sinuses 10 

Mastoid Process 11 

Suprameatal Triangle 12 

Cerebral Venous Sinuses 12 

Practures of the Skull 14 

Fractures of the Skull in Children. . 14 

Fractures of the Skull in Adults. ... 15 
Fractures by Contrecoup or Counter 

Stroke 16 

Hemorrhage in Fractures of the 

Skull 16 

Injuries to Nerves in Fracture of 

the Skull 19 

THE MENINGES. 

Dura Mater 20 

Arachnoid 21 

Pia Mater 22 

Affections of the Membranes of the 

Brain 22 

Pachymeningitis 22 

Dural Hemorrhage 23 

Meningitis 23 

Pial Hemorrhage 23 

THE BRAIN. 

Circulation of the Brain 25 

Internal Carotid Artery 27 

Anterior Cerebral Artery 27 

Middle Cerebral Artery 28 

Posterior Cerebral Artery 28 

Cerebral Softening 30 

Apoplexy 30 

Crossed Paralysis 32 

Cortical Apoplexy 32 

Cerebral Lobes: Frontal, Parietal, Occip- 
ital, Temporosphenoidal, Central Lobe 

or Island of Reil 32 



Page 

Fissures and Convolutions of the Brain. . 33 

Lateral Surface of the Hemispheres .... 33 

Medial Surface of the Hemispheres ... 34 
Functions of the Cortex of the Brain: 

Cerebral Localization 34 

Functions of the Convolutions on the 
surface of the Cerebrum: Prefrontal 
Area; Midfrontal Area; Speech 
Centre or Broca's Convolution; Post- 
frontal Area; Rolandic Area; Sensory 
Area; Visual Area; Auditory Area; 

Gustatory Area; Olfactory Area. ... 35 

Functions of the Basal Ganglia 37 

Corpus Striatum and Thalamus. ... 37 
Corpora Quadrigemina, Crura Cere- 
bri, Pons Varolii 38 

The Corona Radiata, Internal Capsule, 

and Motor Tract 38 

Craniocerebral Topography 39 

Bony Landmarks; Topographical 

Points 40 

The Lower Level of the Brain 40 

Fissures and Convolutions 40 

Subsidiary Fissures, Convolutions . 41 

The Fissures in Children 42 

The Lateral Ventricles 43 

Cerebral Abscess — Trephining 44 

THE FACE. 

The Frontal Region 45 

The Temporal Region 46 

The Temporal Fascia 47 

The Region of the Cheek 49 

Parotid Gland 51 

The Upper Jaw 54 

The Lower Jaw 63 

The Region of the Eye . 72 

The Eyeball and Optic Nerve 77 

The Eyelids and Conjunctiva 82 

The Lachrymal Apparatus 83 

The Ear 84 

Operations on the Middle Ear 90 

The Nose 94 

Frontal Sinus loi 

Ethmoidal Sinuses 102 

Sphenoidal Sinus, Maxillary Sinus. . 103 

THE MOUTH AND THROAT. 

The Tongue 107 

Roof of Mouth in 

Palatal Arches 112 

Faucial Tonsils 113 

Retropharyngeal Abscess 116 

The Pharynx 117 

Eustachian Tube 118 

Pharyngeal Tonsil 122 

The Larynx 124 

THE NECK. 

Surface Anatomy 128 

Cervical Triangles 131 

Torticollis 140 

vii 



VIU 



CONTENTS. 



Page ( 

Ligation of Arteries 141 

The Cervical Fascias 150 

Lymphatics of the Neck 156 , 

Operations on the Air Passages 161 

Operations on the Thyroid Gland 163 

The Parathyroid Bodies 165 

Oesophagus — Cervical Portion 166 

Cut-throat 168 

Afifections of the Neck 169 

THE THORAX. 

Sternum, Ribs, and Costal Cartilages . . 174 

Thoracic Vertebrae 176 

Soft Parts of Chest 176 

Muscles of Chest 177 

Surface Anatomy of Thorax 180 

Breast or Mamma 182 

Lymphatics of Breast 184 

Abscess of Breast; Tumors 185 

Excision of Breast 187 

The Mediastinum 187 

Pleural Effusions 191 

The Chest Contents 192 

Longitudinal lines; Regions 192 

The Pleurae 194 

The Lungs 196 

Pericardium 201 

The Heart 204 

The Aorta 208 

The Oi^sophagus 211 

The Thoracic Duct 214 

THE UPPER EXTREMITY. 

The Shoulder-Girdle 217 

Bones of the Shoulder 219 

Shoulder-Joint 222 

Muscles of the Shoulder 226 

Surface Anatomy 227 

Axilla 229 

Dislocations of the Clavicle 230 

Dislocations of the Shoulder 232 

Fractures of the Clavicle 241 

Fractures of the Scapula 243 

Fractures of the Upper end of the Hu- 
merus 244 

Epiphyseal Separations 247 

Amputation at the Shoulder-Joint 247 

Interscapulothoracic Amputation 250 

Excision of the Clavicle 250 

Excision of the Scapula . 251 

Excision of the Head of the Humerus. . 251 
Diseases of the Shoulder- Joint and Bursas 253 

Axillary Vessels 257 

Axillary Lymphatics 263 

Abscesses of Axilla 264 

THE ARM. 

The Humerus 267 

Muscles of the Arm 267 

Intermuscular Septa 271 

Surface Anatomy 271 

Brachial Artery 272 

Amputation of the Arm 275 

Fractures of the Humerus 276 

Operations on the Arm 279 

REGION OF THE ELBOW. 

Bones of the Elbow 280 

Elbow-Joint 282 

Muscles of the Elbow 284 



Page 

Surface Anatomy 287 

Veins of the Elbow 288 

Brachial Artery 290 

Dislocations of the Elbow 291 

Fractures in the Region of the Elbow. . . 295 
Diseases of the Olecranon Bursa; Diseases 

of the Elbow-Joint 300 

Resection of the Elbow 301 

Amputation at the EIVjov/ 302 

THE FOREARM. 

Bones 303 

Movements of Pronation and Supination 304 

Muscles 305 

Surface Anatomy 312 

Arteries 3 14 

Nerves 317 

Fractures 321 

Amputation 326 

Operations 328 

REGION OF THE WRIST. 

Bones of the Wrist 330 

Inferior Radio-ulnar Articulation 332 

Wrist-Joint 333 

Anterior Annular Ligament 335 

Posterior Annular Ligament 336 

Surface Anatomy of the Wrist 338 

Compound Ganglion 342 

Fractures of the lower end of the Radius 

and Ulna 342 

Dislocations at the Wrist 345 

Excision of the Wrist 347 

Amputation at the Wrist 347 

THE HAND. 

Bones of the Hand 349 

The Phalanges 351 

Joints 352 

Muscles 353 

Surface Anatomy 354 

Palmar Fascia 357 

Arteries 358 

Nerves 360 

Dislocations 362 

Fractures 364 

Wounds 364 

Abscesses 365 

Lymphatics 368 

Amputations 368 

THE ABDOMEN. 

Surface Anatomy 370 

Abdominal Viscera 372 

Abdominal Walls 374 

Muscles of the Abdomen 375 

Vessels of the Abdominal Walls 378 

Abdominal Incisions 381 

Herniae 3*^2 

Umbilical 383 

Inguinal Congenital 383 

Acquired Inguinal Hernia 385 

Radical Cure 387 

Femoral Hernia 390 

The Lumbar Region 392 

Lumbar Fascia 393 

Lumbar Abscess 394 

Lumbar Incisions 395 

The Interior of the Abdomen 396 

Peritoneum 396 



CONTENTS. 



IX 



Page 

Abdominal Viscera 399 

Stomach 401 

Affections of the Stomach 403 

Operations on the Stomach. . . . 405 

The Small Intestine 406 

Duodenum 408 

Jejunum and Ileum; Operations 409 

The Mesentery 410 

The Large Intestine 411 

Caecum and Appendix 414 

Appendicitis 414 

The Colon 414 

The Liver 416 

Wounds and Injuries 417 

Abscess 420 

Gall- Bladder and Biliary Passages. 420 

Gall-Stones 422 

The Pancreas 422 

Cysts and Abscesses 423 

The Spleen 424 

Splenic Enlargement 424 

Wounds 424 

The Kidneys 424 

Displacement of the Kidneys. . 427 

Tumors of the Kidney 427 

Abscess of the Kidney 428 

Operations on the Kidney. . . . 428 

The Suprarenal Gland 438 

The Ureter and Renal Pelvis 430 

Operations on the Ureter 43 i 

THE PELVIS. 

Pelvic Walls 434 

Pelvic Floor 435 

Pelvic Fascia 436 

Iliac Vessels 438 

Pelvic Viscera 438 

Rectum and Anal Canal 440 

Blood-Vessels 442 

Affections of Rectum and Anus 442 

Imperforate Anus 442 

Hemorrhoids 443 

Fistula 443 

Fissure 443 

Excision of Rectum 444 

Bladder 447 

Bladder in the Female 448 

Cystoscopic Examination.. . . ,. 448 

Operations on the. Bladder. . . . 448 

Prostate 450 

Hypertrophy 450 

Prostatectomy 451 

Abscess 452 

Seminal Vesicles 453 

Vas Defferens 454 

Development of the Urogenital System . 454 

Female Generative Organs 454 

Uterus 456 

Ovary 456 

Fallopian Tubes 457 

Vagina. 457 

Ureter in the Female 458 

Blood-Vessels 458 

Lymphatics ; 459 

Pelvic Examinations 459 

Operations on the Female Pelvic Organs 460 

Hysterectomy 461 

Oophorectomy 461 

Vaginal Hysterectomy! 462 

The Female External Genitals 462 

Clinical Considerations 463 

Female Perineum 464 



Page 

Male External Genitals. ... 465 

Penis 465 

Scrotum 467 

Testicles 468 

Epididymis 468 

Spermatic Cord 469 

Urethra 470 

Muscles 471 

Passage of Sounds and Cathe- 
ters 471 

The Male Perineum 472 

The Perineal Fascias 473 

The Perineal Spaces 474 

Practical Application 475 

Rupture of the Urethra 475 

Median Lithotomy 475 

Lateral Lithotomy 476 

Anal Triangle and Ischiorectal 

Region 476 

THE BACK AND SPINE. 

Surface Anatomy 477 

The Vertebral Column 478 

Curves 478 

Movements 478 

Deformities of the Spinal Column. . 47S 

Kyphosis 479 

Lordosis 479 

Scoliosis 479 

Affections of the Spinal Column. . . 481 

Injuries of the Spinal Column 482 

Spinal Cord and its Membranes .... 483 

Transverse Spinal Lesions 484 

Spinal Meninges 484 

Spinal Hemorrhage 486 

Functions of the Cord and Spinal 

Localization 487 

Lesions of the Cord 487 

Operations on the Spine 488 

THE LOWER EXTREMITY. 

General Considerations 489 

The Bony Pelvis 489 

Mechanisim of the Pelvis 490 

Fractures of the Pelvis 491 

Attachment of the Lower Extremities to 

the Trunk 491 

Anteroposterior Equilibrium 492 

Lateral Equilibrium 493 

Deviations of the Spine above the 

Sacrum 495 

Distortions Accompanying Affections of 

the Lower Extremities 496 

Measurement of the Lower Limbs 497 

Walking 498 

THE REGION OF THE HIP. 

Bones of the Hip 499 

Muscles of the Hip 503 

Surface Anatomy 504 

Ligation of the Gluteal, Sciatic, and 

Internal Pudic Arteries 505 

The Hip-Joint 506 

Dislocations of the Hip 508 

Mechanism of the Production of . . . 509 

Reduction of 512 

Congenital Luxations of Hip 514 

Coxalgia 515 

Hip Abscess 516 

Coxa Vara 517 



CONTENTS. 



Page 

Coxa Valga 517 

Operations on the Hip-Joint 517 

Lateral Operations 517 

Anterior Operations 519 

Inferior Operations $iq 

THE THIGH. 

Muscles 520 

Surface Anatomy 522 

Scarpa's Triangle 522 

Femoral Artery 523 

Hunter's Canal 524 

Long Saphenous Vein 525 

Lymphatics 527 

Sciatic Nerve 527 

Fractures of the Femur 529 

Fracture of Neck 529 

Fracture through the Trochan- 
ters 531 

Fracture of the Shaft 53 1 

Amputation at the Hip-Joint 532 

Amputation of the Thigh 532 

REGION OF THE KNEE. 

Surface Anatomy 533 

The Knee-joint 534 

Movements 534 

Bones 534 

Ligaments 535 

Bursae of the Knee 538 

Fracture of the Patella 539 

Dislocation of the Patella 540 

Dislocation of the Knee 541 

Dislocation of the Semilunar Carti- 
lages 541 

Epiphyseal Separations 541 

Resection of the Knee 542 

Tuberculous Disease of the Knee- 
joint 543 

Knock- Knee and Bow-Legs 543 

Osteotomy 544 

Ligation of the Popliteal Artery 544 

Amputation through the Knee-joint . . . 544 

THE LEG. 

Surface Anatomy 546 

Muscles of the Leg 546 

Fascia of the Leg 548 

Arteries of the Leg 548 

Veins of the Leg 550 

Varicosities of 550 

Lymphatics of the Leg 551 

Fractures of the Leg 551 

Amputation of the Leg 552 



REGION OF THE ANKLE. 

Pagb 

Surface Anatomy 553 

Ankle-joint 554 

Ligaments 554 

Movements 554 

Tuberculosis of the Ankle 555 

Excision of the Ankle 555 

Sprain of the Ankle 556 

Dislocations of the Ankle 556 

Fractures of the Ankle 557 

Fracture by Eversion or Pott's 

Fracture 557 

Fracture by Inversion. 558 

Amputations at the Ankle 559 

Syme's 559 

Pirogofif's 560 

REGION OF THE FOOT. 

The Construction of the Foot 561 

Diseases and Injuries of the Foot 561 

Treatment of Affections of the Feet. . . . 562 

Bones of the Foot." 562 

Arch of the Foot 563 

Joints and Ligaments of the Foot 564 

The Ligamentous Support of the Arch 

of the Foot 566 

Muscles of the Foot 568 

Action of the Muscles in Supporting 

the Arch 568 

Action of the Muscles as Flexors 

and Extensors 569 

Action of the Muscles as Abductors 

and Adductors 570 

Surface Anatomy of the Foot 570 

Tendons of the Foot 571 

Joints of the Foot 572 

Arteries of the Foot 572 

Amputations 574 

Chopart's 575 

Lisfranc's 575 

Plantar Abscess 575 

Deformities of the Feet 576 

Talipes Varus 576 

Talipes Valgus 577 

Flat Foot 577 

Talipes Equinus 578 

Talipes Calcaneus 578 

Talipes Cavus 578 

Hallux Valgus 579 

The Toes 579 

Ingrown Nail 579 

Hammer Toe 579 

Luxation of the Toes 580 

Metatarsalgia 580 

Resection of the Metatarsophalan- 
geal Joint 380 

Amputation of the Toes 581 



APPLIED ANATOMY. 



THE SCALP. 



The scalp is formed by the movable soft tissues which cover the skull. It is 
composed of three layers: skin, superficial fascia, -awA occipitofrontalis muscle \\'\\h 
its aponeurosis. It is attached to the underlying pericranium by loose connective 
tissue called the subaponeurotic layer. The pericr'anium, or periosteum of the skull, 
is loosely attached to the bones by a small quantity of connective-tissue fibres called 



Epicranial aponeurosis 

Superficial fascia 

Skin 




by some anatomists the subpericranial connective tissue. At the sutures, however, it 
is very firmly attached. 

The principal affections of the scalp are wounds, inflammation, affections of 
the blood-vessels, tumors, and neuralgia. The peculiarities of these affections are 
determined by the anatomical structure of the parts. 

The skin of the scalp is probably the thickest in the body, although not so 
dense as that of the heel. Besides the hair, it contains abundant sweat and sebaceous 
glands. These latter are connected with the hair-follicles and are near the surface. 
The skin increases in thickness from the frontal to the occipital region. 

The superficial fascia consists of a net-work of connective-tissue fibres which 
run from the skin above to the aponeurosis of the occipitofrontalis below. In its 
meshes are fat, blood-vessels, nerves, and lymphatics. The hair-bulbs often pierce 
the skin and extend into this layer. 

The fibres of the superficial fascia bind the skin so firmly to the aponeurosis 
beneath that when the skin is moved the aponeurotic layer is carried with it. The 




2 APPLIED ANATOMY. 

arrangement of the fibres is shown in Fig. 3. P'ibres starting from the point A not 
only pass directly down to B, but also to each side to the points Cand D. In the 
same way, fibres starting from B not only pass upward to A, but also forward to E 
and backward to F. Now, if the skin is moved in the direction of the forward arrow, 
the fibres E B and A D are tightened and drag the aponeurosis forward. If the skin 
is moved in the direction of the backward arrow, the fibres A C and F B are tight- 
ened and so drag the aponeurosis backward. Thus it is seen that the aponeurosis 
must follow the movements of the skin. 

The occipitofrontalis muscle with its aponeurosis arises from the supe- 
rior curved line of the occiput and is inserted into the skin of the frontal region. 




Skin 

Super 

Aponeurosis 

Subaponeurotic connective tissue 

Pericranium 
_ Subpericranium 

•4 Skull 

! — Uuta mater 



Merkel describes the epicranial aponeurosis as dividing into two layers, one inserting 
into the skin and the other into the rim of the orbit {Haiid. der top. Anat. Bd. i, p. 
17). The bellies of the muscle are comparatively short, about 5 cm. in length, the 
remaining tissue extending between them constituting the aponeurosis. As it comes 
downward from the temporal ridge, over the 
sides of the head, the aponeurosis becomes 
thinner and gives attachment by its superficial 
surface to the anterior and superior auriadar 
muscles. It then proceeds downward to be 
attached to the upper edge of the zygoma. 




Skin 



\:ioneurosis 




Fig. 3. — Diagram illustratitiK the melhod of attach- 
ment of theskin to the aponeurosis of the occipitofrontalis 
muscle. 



Fig. 4. — Showing now the periosteum in 
childhood dips between the bones in the line of 
the sutures. 



Contraction of the occipitofrontalis muscle causes the skin of the forehead to wrinkle 
transversely. It is a muscle of expression, and blends with the pyraniidalis nasi 
and corrugator supercilii. It is supplied by branches of the facial nerve. 

The subaponeurotic tissue is very loose and abundant, so that it does not tend 
to confine the movements of the scalp, but favors them. Hence the scalp is readily 
torn loose from the skull in scalping, machinery accidents, etc. This tissue is so 
loose that effusions accumulate here and spread extensively. It contains only a few 
blood-vessels. 

The pericranium in its normal condition is a thin, tough membrane containing 
few blood-vessels. Except at the sutures, where it is firmly attached and dips 
down between the bones, it is comparatively easily stripped from the skull and 



THE SCALP. 3 

does not convey much nourishment to it. It is deficient in osteogenetic or bone- 
forming properties, so that when it is raised off the skull in operations, and the 
bone removed from beneath, as occurs in trephining, fractures, etc. , new bone is not 
produced. 

The subpericranial tissue is so scanty and loose, particularly in infancy, that 
it readily allows the pericranium to be raised and effusions to occur beneath. 



THE ARTERIES OF THE SCALP. 

The scalp is supplied by the frontal, supra-orbital, and sometimes a small 
branch from the lachrymal arteries, from the ophthalmic; by the temporal, through 




Temporal 



Transverse facial 



Posterior auricular 
Occipital 



Fig. 5. — Arteries of the scalp. 



its anterior and posterior branches; and by the posterior auricular and the occipital 
arteries from the external carotid. These arteries communicate freely with each 
other, not only laterally, but also across the top of the scalp. It is not unusual to 
see a large branch of the temporal communicating directly with the occipital. 

The temporal artery begins in the substance of \.h& parotid gla7id, just below 
the condyle of the jaw, and mounts over the zygoma, a centimetre (or less) in front 
of the ear. It lies on the temporal fascia and its pulsations can be felt at this point, 
if desired, during the administration of an anaesthetic. About four centimetres ( 1 5^ 
in. ) above the zygoma, it divides into the anterior and posterior branches. The 
auriculotemporal branch of the fifth nerve lies just in front of the ear and between it 
and the temporal arterv. 

The occipital artery mounts to the scalp in the interval between the pos- 
terior border of the steniomastoid muscle and the anterior border of the trapezius. 
It is about midway between the posterior border of the mastoid process and the 
occipital protuberance. If it is desired to expose it from this point forward, the 



APPLIED ANATOMY. 



sternoniastoid, splenius capitis, and tracheloniastoid muscles will have to be cut, 
because it passes beneath them. The occipitalis major nerve lies to the inner side of 
the artery. 



Occipital artery 



Complexus 

Inferior oblique 

Trapeziu; 

Trachelomatoid 

Splenius' 



Levator angul 
scapulae 



Superior oblique 

Sternoniastoid 
Tracheloniastoid 
Splenius 




Spinal accessory 
nerve 



Hypoglossal nerve 



Fig. 6. — Occipital artery. 

LYMPHATICS OF THE SCALP. 

The lymphatics anteriorly near the median line pass down between the orbits to 
reach the submaxillary nodes. Those of the anterior parietal and temporal regions 
empty into the pre-auricular nodes; those of the posterior parietal and temporal, 
into the nodes behind and below the ear; and those of the occipital region into the 
occipital nodes. Infectious troubles of these regions, therefore, will cause enlarge- 
ment of the corresponding nodes. 

AFFECTIONS INVOLVING THE LAYERS OF THE SCALP. 

Wounds of the scalp are common. Incised wounds bleed more freely and the 
hemorrhage is more difficult to control than in wounds elsewhere on the surface. 
This is due to the exceedingly free blood supply and to the peculiar arrangement of 
the blood-vessels in the tissues. 

Small wounds of the scalp do not gape, particularly if they are longitudinal in 
direction and not very deep. The skin is so intimately bound to the aponeurosis 
beneath that displacement is impossible. If the cut is deep enough to divide the 
aponeurosis extensively, especially if the wound is transverse, gaping is marked. 
This is produced by contraction of the two bellies of the occipitofrontalis muscle, 
which pulls the edges apart. 

Bleeding is apt to be persistent and hard to control because the arteries running 
in the deep layers of the skin and fibrous trabeculae are firmly attached and, there- 
fore, when cut, their lumen cannot contract nor their ends retract. When large 
flaps are torn in the scalp, they rarely die because of their free blood supply, and 
sloughing is limited to the parts which are actually contused. As the subaponeur- 
otic space is often opened, if the wound is sewed too tightly shut, subsequent bleeding 
instead of escaping externally may extend widely under the aponeurosis. Inasmuch 
as hair and dirt are often crushed into these wounds, great care should be taken to 



THE SCALP. 5 

disinfect them. A cut will open the hair bulbs and sebaceous glands, and, as the hairs 
project into the subcutaneous tissue, they may serve as a starting point for infection. 

Contraction of the occipitofrontalis muscle may prevent healing in extensive 
wounds. To avoid this the scalp is covered by a recurrent bandage or otherwise fixed. 

Lacerated wounds do not bleed so freely as do incised wounds, but they are 
accompanied by a more extensive loosening of the scalp. Large flaps of tissue are 
frequently raised and turned to one side. The most severe of these injuries have been 
produced by the hair being caught by a revolving shaft, tearing nearly the whole 
scalp off. Its loose attachment to the pericranium and bone beneath by the loose 
subaponeurotic tissue, readily explains the reason of these extensive detachments. 

Contusions cause only a moderate amount of swelling, which is usually circum- 
scribed. While the skin is not broken, the blood-vessels and other tissues beneath 
are often ruptured, and, therefore, extravasation of blood occurs. When this is con- 
fined to the superficial fascia, it is small in amount and limited in area. It does not 
tend to work its way for any great distance beneath the skin. If the extravasation 
extends below the aponeurosis, it may cover a considerable area of the skull. When 
it occurs beneath the pericranium it is called cephalhcematoma, or in the new-born 
capnl succedaneum. Caput succedaneum is found almost always on the right side, 
involving the parietal eminence. It is limited 
by the attachment of the pericranium at the 
sutures. 

Hcs7natomas of the scalp possess the pecu- 
liarity of being soft in the centre and sur- 
rounded by a hard cedematous ring of tissue. 
In cephalhaematoma of long standing this ring 
may ossify, and the new bone may even extend 
and form a more or less perfect bony cyst. 
This, however, is very rare. 

Hsematomas produced by blows on the 
head are often mistaken for fractures. The 
raised edge is so hard as sometimes to be 

thought to be the edge of broken bone. The tis- Fig 7.— Haematoma on the forehead of a child, 

sues beneath the skin at the site of impact 

seem to be pulpified and remain perfectly soft to the touch; the smooth unbroken 
skull can usually be felt over an area equal to the site of impact. Surrounding this 
soft area is the hardened ring, composed of tissues between the skin and the bone, 
into which serum and blood have been effused. 

Inflaviniation and abscess are caused by infected wounds, furuncles, erysipelas, 
caries of the skull and suppurating sebaceous cysts. 

The scalp is a favorite location for erysipelas; if not started primarily by an 
infected wound, the scalp may be involved secondarily by extension from the face. 

Caries of the skull is often of syphilitic origin. 

Abscesses maj occur in three places: 

1. Subcutaneous. 

2. Subaponeurotic. 

3. Subpericranial. 

I. Subcutaneous abscesses are usually small and do not tend to spread but 
rather to discharge through the skin. This is because the firm fibrous trabeculae 
prevent lateral extension. Furuncles are quite common in childhood; they are, of 
course, superficial to the aponeurosis. Sebaceous cysts are especially common in 
the scalp and they sometimes suppurate. The orifice of the obstructed duct is not 
usually visible. Sometimes in a small cyst a black spot on its surface indicates 
the opening of the duct. By means of a needle or pin this opening can be dilated 
and some of the contents expressed. Of course, if nothing further is done it will 
reaccumulate. When these cysts become inflamed they become united to the skin 
above so that it has to be dissected off. If pus forms, it either remains localized to 
the cyst or bursts through the skin and discharges externally. It does not tend 
to burrow under the skin laterally on account of the fibrous trabeculae uniting the 




APPLIED ANATOMY. 



skin and aponeurosis. The aponeurosis beneath is intact, therefore the pus does 
not get below it. The cyst, with the Hning membrane entire, should be removed, 
otherwise it will recur. 

2. Subaponeurotic abscesses come from infected wounds, erysipelas, or caries of 
the bones. It is not desirable to close deep wounds of the scalp too tightly. Some 
suppuration is liable to occur which, not finding an easy escape externally, may 
spread under the aponeurosis if the wound has been deep enough to divide it. 
Infection of wounds is the most frequent source of these abscesses, hence the desira- 
bility of providing for drainage for at least a short period. In erysipelas, serous 

effusion, which may become purulent, oc- 
curs in the subaponeurotic tissue, as well as 
in the layers above. It may sink down- 
ward and point in the temporal, occipital, or 
frontal region. In the temporal region the 
descent of the pus may be limited by the 
attachment of the lateral expansion of the 
aponeurosis to the zygoma. The attachment 
of the occipitalis muscle posteriorly to the 
superior curved line of the occiput prevents 
the effusion from coming to the surface at 
that point. The liquid accumulates low down 
on the forehead over the orbits, being pre- 
vented from entering by the attachment of 
the orbitotarsal ligament, and tends to point 
close to the median line. The frontal muscles 
of the two sides are apt to be slightly sep- 
arated, leaving a weak spot just above the 
root of the nose, and this is where fluctua- 
tion can most easily be felt. These accumu- 
lations in the frontal, temporal, and occipital 
regions may require incisions for their evac- 
uation and drainage. Suppuration arising 
from carious bone readily perforates the 
pericranium and then infiltrates the loose 
subaponeurotic tissue. The bones of the vault of the skull are not infrequently 
affected by syphilitic disease, producing caries and suppuration, which invade the 
subaponeurotic space. 

3. Subpericranial abscesses are comparatively rare. They usually start from 
diseased bone and spread laterally beneath the pericranial tissue. The pus may be 
limited to a single bone on account of the firmer attachment of the pericranium at the 
site of the sutures. To avoid breaking into the subaponeurotic space, a free opening 
should be made into the abscess so as to allow the pus to drain externally. 




Fig. 8. — Arterial angioma or cirsoid aneurism. 



AFFECTIONS OF THE BLOOD-VESSELS. 

The arteries or veins alone may be affected, or both may be invoh'ed. 

Arterial varix is the name given to an enlargement of a single artery. It forms 
a swollen, tortuous, pulsating mass in the course of the artery. The temporal artery 
is liable to be so affected, particularly its anterior branch. 

Cirsoid ajieiirism, or aneurism by anastomosis, is formed by numerous enlarged 
arteries. It is sometimes called an arterial angioma ox plexiforni angioma. The 
veins are also somewhat involved. Pulsation is marked. 

Venous angioma is a tumor formation in which the venous blood is contained in 
large spaces, which are lined with endothelium, instead of in normal veins. 

Telangiectasis or ncevKS is formed of enlarged capillaries. It is often called 
port wine mark, mother's mark, etc. 

Aneurismal varix, or arterioveno7is aneurism , is where an adjacent artery and 
vein being wounded, — as the temporal artery and vein, — the blood passes directly 
from the artery into the vein. 



THE SCALP. 7 

Varicose aneurism is where a sac intervenes between the artery and vein, so 
that the blood passes first from the artery into the sac and then into the vein. The 
temporal artery with its companion vein has been so affected. 

Treatment of Vascular Affections of the Scalp. — Vascular tumors are 
usually ligated and excised. Acupressure pins may be passed under the larger 
arterial trunks, but the exceedingly free anastomosis renders thorough excision 
preferable; even this is not seldom unsuccessful. 



TUMORS OF THE SCALP. 

Sebaceous cysts arise from obstructed sebaceous glands; the contents consists of 
epithelial cells, fat, and cholesterin. They sometimes calcify. They spread in the 
subcutaneous tissue, stretching and raising the skin above and causing atrophy of 




Fig. 9. — Sebaceous cyst of scalp. 




Fig. 10. — Meningocele. 



the hair bulbs, but do not involve the epicranial aponeurosis below. In removing 
them, if they have never been inflamed, they can readily be turned out through a 
slit in the skin. The subaponeurotic space will not be opened, therefore their 
removal is not often followed by bad results. 

Encephalocele is a tumor .formed by a protrusion, through the skull, of the 
membranes of the brain, containing brain matter and cerebrospinal fluid. 

Meningocele, or a tumor containing the meninges of the brain and cerebrospinal 
fluid, is more rare in the skull than is the case when the spine is affected. It pro- 
trudes through an unossified part of the skull, and, according to Sutton, two-thirds of 
the cases occur in the occipital region, between the foramen magnum and torcular 
Herophili. He characterizes it as a hydrocele of the fourth ventricle, and says that 
nine out of ten cases die if operated on. The next most frequent seat for meningo- 
cele is at the root of the nose (Fig. 10). 

Cephalhydrocele is the name given to a pulsating tumor communicating with the 
interior of the skull through a traumatic opening. It contains cerebrospinal fluid. 

Dermoid tumors occur in the median line and, according to Sutton, are most 
common over the anterior fontanelle and external occipital protuberance. They often 
have a thin pedicle attaching them to the dura mater and may grow either inside or out- 
side the skull. They are formed by an inclusion of some of the tissue of the ectoderm 
by the bones as they approach from each side to ossify and unite in the median line. 

A congenital tumor located at the root of the nose is probably an encephalocele; 
one located at the anterior fontanelle is probably a dermoid; a tumor in the occipital 
region may be either, but a dermoid is apt to be higher up than an encephalocele. 



APPLIED ANATOMY 



THE SKULL 

The skull is the bony framework of the head. It is divided into the bones of 
the cranium and those of the face. The hyoid bone is usually classified with the 
bones of the head. 

The cranium consists of the bones forming the brain case. They are the 
occipital, two parietals, the frontal, two temporals, the sphenoid, and the ethmoid. 

The bones of the face are fourteen in number, there being two single bones 
and six pairs. The single bones are the mandible, or inferior maxilla, and vomer ; 
the pairs are the superior maxilla, malar, nasal, palate, lachrymal, and inferior 
turbinated bones. 

THE SKULL IN CHILDHOOD. 

The skull of the infant is markedly different from that of the adult. At birth the 
face is quite small and undeveloped, while the cranium is relatively large. The frontal 

and parietal eminences are very marked. 

^^ — vj^^,,^ The vault of the skull is not entirely os- 

^^m ^^^ sified and the sutures are not completed. 

.^^Kk . i^b^. The bones of the base of the skull 

"^^^^^ ' "^^^ originate in cartilage, while those of the 

vault originate in membrane. This mem- 
A \ ""^^^ brane has one or more centres of ossi- 

M ^ ^^11^^ fication appearing in it for each bone. 

^K- ^ '^^ P| k These centres increase in size and finally 

^' I ^ meet at the edges of the bone, thus form- 

ing the sutures. At the time of birth the 
sutures are represented by membrane, 
which joins the adjacent bony edges. 

The frontal bone has two centres of 
ossification; one for each side. These 
form a suture in the median line of the 
forehead which becomes obliterated in 
the course of the first or second year. 
Traces of it in the shape of a groove or 
ridge can sometimes be seen or felt in the 
adult skull. The frontal cmine7ices are 
far more marked in childhood than later 
in life and give to children the promi- 
nent forehead which is so characteristic. 
A similar peculiarity is seen in the 
parietal bones, the parietal eminences 
being quite prominent. On this account, they are often injured in childbirth, 
sometimes being compressed by the obstetrical forceps, and are frequently the seat of 
hcematoma neonatorum. The cranial bones not being firmly united allow of a certain 
amount of play or even overlapping, thus facilitating the delivery of the head at birth. 
Fontanelles. — At the juncture of the various bones are six spaces called fontan- 
elles. Two, the anterior and posterior, are in the median line of the cranium, and 
four, the two anterolateral and two posterolateral, are at the sides. The fontanelles 
are situated at the four corners of the parietal bones. 

The anterior fontanelle is the largest. It is diamond-shaped and formed by the 
frontal suture in front, the interparietal behind, and the coronal at each side. It is usu- 
ally closed by the end of the second year, but may be delayed until the fourth. In 
rickets and malnutrition the fontanelles remain open longer than would otherwise 
be the case. 

The posterior fontanelle is formed by the juncture of the parietal (sagittal) suture 
with the lambdoidal suture. It is triangular in shape with the apex forward between 
the two parietal bones, the sides passing down, one to the right and the other to the 
left of the top of the occipital bone. 




Anterior. 



Fig. II. — Infant's skull, showing posterior and anterior 
fontanelles. 



THE SKULL. 



9 




Fig. 12.- 



-Infant's skull, showing: anterolateral and postero- 
lateral fontanel les. 



These fontanelles are of the greatest importance in diagnosing the position of 
the head during labor. If the examining finger encounters first a large diamond- 
shaped or four-cornered depression with its anterior angle more acute than the pos- 
terior, the accoucheur will know that it is the anterior fontanelle which is presenting. 
By following one of the sutures backward he will come to a triangular or Y-shaped 
ridge which will be recognized from its shape as being the posterior fontanelle. He 
will then know that the position of the 
head is occipitoposterior. If the posi- 
tion is the more usual occipito-anterior 
one, the finger will first encounter the 
posterior fontanelle wiih its three sutures, 
which are distinctly recognizable. On 
following the suture which leads back- 
ward, the four-cornered anterior fon- 
tanelle will be felt. The various sutures 
constituting the fontanelles can usually 
be distinctly felt, and, as the presenta- 
tions are nearly always occipito-anterior, 
the fontanelle that will usually be first 
felt will be the posterior, and the sutures 
forming it can readily be counted. 

The antero- 2i\\<\ posterolateral fon- 
tane//es, located at the anterior and pos- 
terior angles of the parietal bones, are 
of no service in diagnosing the position 
of the head. They are indistinct, nearly 

closed, and thickly covered by tissue. In injuries to the skull in young children 
and infants, we should not mistake the fontanelles and lines of the sutures for 
fractures. Fissures extending into the occipital bone from the posterolateral fonta- 
nelles are normal at birth and not due to injury. 

Dura Mater. — The dura mater in children is more firmly attached to the 
interior of the skull than in adults. If, therefore, a true fracture does occur, lacera- 
tion of the dura is more 
liable to be produced. This 
firm attachment also pre- 
vents the formation of epi- 
dural hemorrhages, because 
the force of the blow is not 
sufficient to loosen the dura 
from the bone, and when 
the middle meningeal artery 
is torn, as Marchant has 
pointed out, the bleeding 
is more apt to be external 
than internal. 

Cells and Air-sinuses. 
— The infant has the bones 
of the face so slightly developed that there is no room for the cavities which after- 
ward develop in them. The ridges of the bones also become more marked as age 
advances. The young child has no superciliary ridges. 

The maxillary sums, or antnim of Highmore, and the mastoid antrum are the only 
cavities that exist at birth. They are both much smaller than they ultimately become. 
The mastoid antrum in relation to the size and age of the child is comparatively 
large, being about fixe millimetres in diameter. As the bone in the child is unde- 
veloped, and the tympanum lies nearer to the surface, the antrum likewise is some- 
what higher and nearer to the surface than is the case in adults. This should be 
borne in mind when operating on the bone in this region (Fig. 13). 

The frontal, ethmoidal, and sphenoidal si?i7ises appear about the seventh year, 
but it is not until puberty is reached that they really begin to develop. The mastoid 




Mastoid antrum 



External 
auditory meatus 

Mastoid process 



Fig. 13. — The surface of the temporal bone has been chiselled 
showing the relative size and position of the mastoid antrum and external 
auditory meatus. 



lo 



APPLIED ANATOMY. 




Fig. 14. — Transverse section of the skull showing its 
variations in thickness at different points. 



cells likewise appear at puberty and increase with age. At birth, they are repre- 
sented by simple cancellous bone. 

THE SKULL IN ADULTS. 

As the child grows, the bones of the face increase more rapidly than do those 

of the vault. The bony prominences become marked, due to the action of the 

various muscles of mastication, expres- 
sion, etc., inserted into them. The 
face is much larger in size in proportion 
to the calvarium than was the case in 
infancy. While in infancy bone is prac- 
tically homogeneous, in late childhood 
and early adult life cavities begin to 
develop in it. 

Outer and inner tables of compact 
tissue are formed, separated by diploic 
structure. The frontal, ethmoidal, and 
other air-sinuses are an exaggeration 
of these diploic spaces. They are lined 
with mucous membrane and communi- 
cate with the nasopharynx. The diploe 
first begins to appear about the age of 

ten years, but is not well formed until early adult life. It contains large veins, 

called the diploic veins, which communicate with the veins both of the inside and 

outside of the skull. In injuries to the skull 

bleeding from these veins is rarely trouble- 
some and usually stops spontaneously. 

The skull is thinner in the white than 

in the negro race. It is thickest over the 

occipital protuberance and mastoid proc- 
esses. The bone is thinnest in the temporal 

and lower occipital regions. The two tables 

are separated widely from one another in 

the region of the frontal sinuses. 

Tables. — The inner table is thinner and 

more brittle than the outer one, and in frac- 
tures it is almost always more extensively 

splintered than the outer. In rare cases the 

outer table may be temporarily depressed by 

a glancing blow and spring back into place 

without showing any depression, while the 

inner table may be fractured. 

The two tables are not exactly parallel. 

Where the skull is thin, as in the temporal 

and occipital *egicns, they are close to- 
gether; where it is thick, they are farther 

apart. The outer surface of the skull is 

comparatively even and smooth. The inner 

surface is quite uneven, being depressed in 

places to receive the convolutions of the 

brain. For this reason it is necessary to use 

the trephine with great care, as it may cut 

through on one side of the circle and injure 

the dura mater before it cuts through the 

other part. 

The sutures of the skull begin to ossify 

at about the age of forty years and continue to fuse until about the eightieth year. 
Frontal Sinuses. — The frontal sinuses begin to develop at the age of seven 

years, but do not increase rapidly in size until puberty. When adult age is reached 




Fig. 15.— Frontal sinus of one side; the anterior wall 
has been cut away, exposing its interior. 



THE SKULL. 



II 



they are well developed. They may extend well out over the orbits, reaching to 
within a short distance of the temporal ridge, while in other instances they do not go 
beyond the supra-orbital notches. In height they may reach the lower portion of 
the frontal eminences or may cease at the level of the superciliary ridges. The size 
of the sinus cannot be judged from the size of the bony prominences. Neither is the 



Mastoid antrum 

Supraineatal spine 




Mastoid cells 
Fig. i6. — Surface chipped away to show the mastoid antrum and cells, the latter unusually well developed. 

size nor sex of the individual any criterion. In a small female we have seen them of 
considerable size. When diseased sufficiently to give rise to symptoms, they will be 
found to be quite large. They are separated from each other by a septum, and if 
extensive are divided into several pockets or recesses. They open into the infundib- 

Superior longitudinal sinus 



Inferior longitudinal sinus 




Straight sinus 
Torcular Herophili 

Lateral sinus 
Occipital sinus 

Superior petrosal sinus 
Sigmoid sinus 
Inferior petrosal sinus 
Jugular vein Cavernous sinus 
Fig. 17. — The cerebral blood sinuses. 

ulum, at the anterior extremity of the middle turbinated bone in the middle meatus 
of the nose. Fracture of the outer wall of the sinus not infrequently occurs without 
involving the inner table. 

Mastoid Process. — The mastoid process is continous with the superior curved 
line of the occiput. It increases in size from the time of birth, but is composed of 
cancellous tissue until after the age of puberty, when the mastoid cells develop. The 
mastoid antrum, a cavity five millimetres in size at birth, which opens into the upper 
posterior portion of the tympanum, is relatively larger at birth than in the adult. 



12 APPLIED ANATOMY. 

It is of importance in operating for infection arising from middle-ear disease. Minute 
veins run from the antrum into the lateral sinus. 

Suprameatal Triangle. — This triangle, so named by Macewen, is formed 
above by the posterior root of the zygoma, anteriorly by the bony posterior wall of 
the external auditory meatus and posteriorly by a line from the floor of the meatus 
passing upward and backward to meet the first line. The mastoid antrum is reached 
by operating through this triangle (see section on Ear). 

Cerebral Venous Sinuses. — The fibrous membrane which lines the inte- 
rior of the skull is composed of two layers which are in most places intimately 
united, forming one single membrane known as the dura mater. The outer 
layer is applied to the bone, while the inner layer covers the brain. In certain 
places these two layers separate to form channels in which venous blood flows ; 
these channels are called sinuses. In certain other places these layers separate and 
enclose some special structure, as the Gasserian ganglion. 

The cerebral sinuses of most importance are the siiperior longitndinal, the lateral 
or transverse, and the cavernoics. 

The superior lotigitudi?ial sinus runs in the median line from the foramen caecum 
in the ethmoid bone in front, to the torcular Herophili behind. As it passes back- 




FiG. i8.— Posterior view of the skull, showing the relation of the superior longitudinal sinus and torcular Herophili 
to the median line and external occipital protuberance. 

ward it inclines more to the right side, so that at the torcular Herophili the left side 
of the sinus is about in the median line. This sinus receives the veins from the 
cortex of the brain and also some from the diploe of the bones above it. A vein 
pierces the upper posterior angle of each parietal bone and forms a communication 
between the superficial veins of the scalp outside and the superior longitudinal sinus 
within. The deviation of the superior longitudinal sinus toward the right, as it 
proceeds posteriorly, is to be borne in mind in operating in this region, as one can 
approach the median line nearer on the left side posteriorly than the right, without 
wounding it. In the parietal region the Pacchionian bodies are surrounded by 
extensions from the longitudinal sinus and free hemorrhage will ensue if the bone is 
removed too close to the median line. 

The torcular Herophili, or confluence of the sinuses, does not correspond exactly 
to the external occipital protuberance or hiion on the exterior of the skull. It is 
a little above and to the right of it. This torcular Herophili is formed by the meet- 
ing of the longitudinal sinus from above, the lateral, or transverse sinuses from 
the sides, the straight sinus from in front and the occipital sinus from below. 

The lateral or transverse sinuses, of which there are two, pass from the torcular 
Herophili toward each side in the tentorium between the cerebrum and cerebellum, 
following the superior curved line of the occiput until just above the upper posterior 
portion of the mastoid process. They then bend downward to within a centimetre of 



THE SKULL. 



13 



the tip of the process and again curve forward to end in the jugular foramen and be 
continued as the internal jugular vein. The S-shaped curve which they make in this 
part of their course has given rise to the name sigmoid sinus. In its course along 
the superior curved line the sinus rises above the level of a line drawn from the inion 
to the centre of the external auditory meatus. 

In operating for cerebellar abscess, care should be taken to place the trephine 
opening sufficiently low down to avoid wounding this sinus. It is in great danger of 
being wounded in operating for septic conditions involving the mastoid antrum and 
cells. Its distance from the surface of the skull varies in different individuals, and it 
gets farther from it as it descends to the level of the tip of the mastoid process. It 



Cavernous sinus 



Circular sinus 



Superior petrosal sinus ■ 

I nferior petrosal sinus 



Sigmoid sini 



Occipital sinus 
Transverse or lateral sinus 




1st — olfactory 



and — optic 

3rd — oculomotor 

4th — trochlear (pathetic) 



5th— trigeminal (trifacial) 

6th — abducent 

7th — facial 

8th— auditory 

9th — glossopharyngeal 

loth — vagus (pneumogastric) 

1 ith — spinal accessory 

12th— hypoglossal 



Superior longitudinal sinus 

Fig. 19. — Exit of cranial nerves and venous sinuses at the base of the skull. 



receives the blood from the posterior lower portion of the cerebrum and upper 
portion of the cerebellum, and communicates with the veins outside the skull through 
the mastoid and posterior condyloid foramina. 

Running along the upper posterior edge of the petrous portion of the temporal 
bone, in the attachment of the tentorium, is the superior petrosal sinus. It connects 
the lateral or transverse sinus about its middle with the caver^ious sinus. More 
deeply situated, and running from the cavernous sinus to the lateral sinus, just as it 
enters the jugular foramen, is the inferior petrosal sinus. 

The petrosal and lateral sinuses are frequently torn in fractures of the skull. A 
fracture passing through the petrous portion of the temporal bone may tear the 
petrosal sinuses, and hemorrhage from the ear might come from this source. A 
fracture through the posterior cerebral fossa may tear the lateral sinus. Leeches 
are sometimes applied behind the ear in inflammation of the brain, with the idea of 
drawing blood from the lateral sinus through the mastoid vein. 

The occipital sinus is usually small and brings the blood up from the region of 
the foramen magnum to the torcular Herophili. 

The straight sinus runs along the line of juncture of the tentorium and falx 
cerebri. It receives the blood from the ventricles of the brain which are drained by 



14 APPLIED ANATOMY. 

the veins of Galen, and the blood from the falx through the inferior longitudinal 
sinus. This latter is usually very small and sometimes almost lacking, the blood in 
that case passing upward to empty into the superior longitudinal sinus. 

The cavernous sinus, — one on each side, — is a large, irregular space on the side 
of the body of the sphenoid bone. It runs from the sphenoidal fissure in front to 
the apex of the petrous portion of the temporal bone behind. In front it is continu- 
ous with the ophthalmic vein, and receives the sphenoparietal sinus which brings the 
blood from the diploe ; behind it communicates with the superior and inferior petrosal 
sinuses. The two sinuses communicate across the median line around the pituitary 
body, forming the circular sinus, and across the basilar process, forming what is 
sometimes called the trajisverse sinus, but which is more correctly described as a 
plexus of veins. 

The cavernous sinus has embedded in its outer wall the third and fourth nerves 
and the ophthalmic branch of the fifth. Farther below and to the outer side of the 
sinus are the superior and inferior maxillary or mandibular branches of the fifth 

3rd nerve 
4th nerve 

Ophthalmic branch of 5th nerve 
6th nerve 




Superior maxillary nerve 

Inferior maxillary (mandibular) nerve 



Internal carotid artery 



Fig. 20. — Transverse section of the right cavernous sinus, showing the position of the nerves and 
internal carotid artery (from a dissection). 

nerve. Within the sinus and toward its lower and inner portion, is the internal 
carotid artery. It is surrounded by the blood-current. Between the carotid artery 
and outer wall of the sinus runs the sixth nerve, held in place by fine, trabecular, 
fibrous bands which pass from side to side in the cavity of the sinus. 

The cavernous sinuses are sometimes torn in fractures of the base of the 
skull, resulting in a traumatic communication between the carotid artery and the 
sinus. The cavernous sinus is not infrequently torn in attempting the removal 
of the Gasserian ganglion, particularly if its ophthalmic branch is attacked. Its 
interior is not one large cavity, but is subdivided by fibrous septa, which pass 
from side to side. It is sometimes the seat of thrombosis and infection, which 
may reach it through the ophthalmic vein in front. 

FRACTURES OF THE SKULL. 

Fractures of the skull are almost always produced by violent contact of the skull 
with some solid body. In some cases the fracture is produced by a blow from a 
moving body, as when a person is struck by a club. In others, the skull is moving 
and strikes a body at rest, as when a person falls and strikes the head on a pave- 
ment. It is not necessary to discuss in detail the mechanism of fractures of the skull; 
it is sufficient to state that nearly all fractures start from the point of impact and 
radiate to distant regions. The effect of fracturing blows on the skull of a child is 
different from their eiTect on the skull of an adult. 

Fractures of the Skull in Children. — A child's skull is thin and weak, and 
while, to a certain extent, fragile is more flexible than that of an adult. It is on this 
account that blows are more liable to expend their force locally, at the point of impact, 
and not produce fractures at a distance. Therefore, it follows that fractures of the 
base are rare in children in comparison with fractures of the vault. Extensive 
fissured fractures are also rare. A blow will crush the skull of a child at the point 
of impact, much as an egg-shell is broken at one spot by hitting it with a knife 
handle. A marked example of this was seen in the case of a small boy who, 




THE SKULL. 15 

while playing, was struck by a baseball on the left frontal eminence. A distinct 
circular depression or cup was produced exactly corresponding to the shape of the 
ball. There were no symptoms of cerebral concussion, because the force of the 
blow was expended on the bone and not transmitted to the brain within. As 
pointed out by Mr. Rickman Godlee, the sutures in very young children being soft, 
the transmission of the force from one bone to another is prevented. 

The diploic structure of the skull is not well developed until adult age, therefore 
the bone is homogeneous. It is also elastic, and, particularly in infants, it may be 
dented without being seriously fractured; these dents are apt to disappear and 
become level with the surrounding bone as the child grows older. The dura mater is 
more adherent in children and fractures are, on that account, more liable to tear it 
and even lacerate the brain beneath. 

Fractures of the Skull in Adults. — As adult life is reached the inner and 
outer tables of the bones become separated, leaving the space between to be filled 
by the diploic tissue. The diploe consists of cancellous bone in the meshes of which 
run the diploic veins and capillaries. Both the inner and 
outer tables are brittle, but the inner especially so. It is 
also harder and more compact than the outer table. On 
account of this difference we find in cases of fracture that 
the inner table is more comminuted than the outer, so that, 
while the outer may show a single line of fracture, the inner 
table immediately beneath may be broken into several frag- 
ments. This is one reason why trephining is so frequently 
resorted to. 

In rare cases there may be depression of the inner , F'g. 2i.-smaii piece of the 

,, ., -'. ^ ^ . . . . . . skull showing hairs imprisoned 

table with none of the outer. A case of this kmd occurred in a linear fracture— actual size, 
during our Civil War. A soldier, while looking over a ram- 
part, was struck a glancing blow by a bullet, on the upper anterior portion of the 
skull. The outer table at the site of injury was not at all depressed, but the inner 
table had a large piece broken off, which injured the membranes. 

The elasticity of the skull is shown in cases of fracture in which hairs are found 
imbedded in the line of fracture. Figure 21 is from such a case. A negro was 
struck on the head by a falling rock and an extensive longitudinal fracture was pro- 
duced in which many hairs were fastened. About a centimetre from the main frac- 
ture was a small fissure, not over a centimetre long, and sprouting up out of it, like 
bushes from the bare ground, were a number of hairs. In such cases the hairs are 
carried into the line of fracture by the force of the blow ; the elastic bone then springs 
back into place and pinches the hairs, thus holding them in place. 

The bones of the adult skull are very strong and firmly fixed. The sutures 
begin to unite at the age of forty years and are likely to have disappeared at the age 
of seventy. Even in young adults the fibrous tissue between the bones has so nearly 
disappeared that they practically act in transmitting force as one continuous bone. 
For these reasons slight blows do not cause fractures. It takes a very heavy blow 
usually to cause a fracture and the force is so great that shock or concussion of the 
brain with disturbance of its functions is a common symptom. 

The force of the blow is expended first at the point of impact, and if a fracture 
occurs it usually starts there. From that point it radiates to other portions of the 
skull, so that fractures of the vault frequently extend to the base. The course 
pursued by the fracture has been formulated into a law by Aran ; that they take a 
straight line from the point of impact on the vault to the base of the skull, and are 
not deflected by the sutures. 

Charles Phelps ("Traumatic Injuries of the Brain") found that in 127 cases of 
fracture of the base of the skull, 12 implicated the base only. So that, if we are able 
to say that there is a fracture of the base of the skull, there are over 10 chances to 
one of its extending up into the vault. In only two were the fractures more than a 
slight fissure ; so that in a marked fracture of the base there would be 63 chances to 
one of its extending into the vault. Also, from Aran's law, we see that, if we diag- 
nose a fracture through the middle ear, we may be pretty sure that the force was 
applied directly above, and be led to trephine accordingly. 



i6 



APPLIED ANATOMY. 



A man fell from an electric light pole and was brought to the hospital with bleed- 
ing from the ear and other symptoms of fracture of the skull. He became wildly- 
delirious, and, feeling sure that the fracture of the base was an extension from the 
vault, although no depression could be felt, he was trephined above the external 
auditory meatus and a large epidural effusion of blood evacuated. He recovered 
and resumed his work. In this case, as soon as the bone was exposed, a thin line 
of fracture was .seen running down to the base in the region of the external ear. 

Fractures by Contrecoup or Counter Stroke. — Fractures by counter 
stroke are now regarded as of much less frequent occurrence than formerly. Charles 
Phelps found in 147 cases of fracture of the base of the skull 12 which had not 
extended from the vault. In these, the force had been applied to the parietal region 
in six, and in five to the occiput; most of the resulting fractures were in the region 



Or! >ital plate of frontal 



Anterior cerebral fossa' 



Foramen rotuntium 



Middle cerebral fossa 



Posterior cerebral fossa 




Cribriform plate of ethmoid 



Lesser winj^ of sphenoid 
Optic foramen 
Anterior clinoid process 
Greater wing of sphenoid 

Sella turcica 

Post, clinoid process 

— Foramen ovale 
_ Foramen spinosum 

— Body of sphenoid 
Petrous portion of temijoral 
Body of occipital 

Internal auditory meatus 



%|to4 s^^^VT]--^ Jugular or post, lacerated 
"^^ ~z!^^m f J foramen 

Sigmoid sinus 



Torcular Herophili 



Fig. 22.— Interior view of the base of the skull, showing the parts most liable to be involved in fractures. 



of the orbit. Only two of the twelve cases were serious fractures, the remaining ten 
being slight fissures, which produced no symptoms. 

Hemorrhage in Fractures of the Skull. — Hemorrhage is a frequent and most 
valuable symptom in diagnosing the existence of fracture and in determining its location. 

Fracture through the anterior cerebral fossa may open the frontal, ethmoidal, or 
sphenoidal cells and cause bleeding from the nose and mouth. 

A fracture through the roof of the orbit causes bleeding into the orbital cavity; the 
blood works its way forward and makes its appearance under the conjunctiva of the 
ball of the eye. Its progress forward toward the lids is blocked by the orbitotarsal 
ligaments, and it therefore works its way downward to the bulbar conjunctiva, under 
which it advances to the edge of the cornea. The ordinary ecchymosis of the lids and 
cellular tissue around the eye is usually due to a rupture of the vessels of the subcuta- 
neous tissue by a blow from the outside, and not to a fracture of the base of the skull. 



THE SKULL. 



17 



Fracture through the middle cerebral fossa may pass through the body of the 
sphenoid or basilar process of the occipital bone and cause bleeding into the mouth. 
It may also cause an accumulation of blood behind the posterior wall of the pharynx, 
pushing it forward. When it passes through the petrous portion of the temporal 



Anterior branch 
piercing the bone 




Posterior branch 



Posterior meningeal 
from vertebral 

Middle meningeal 

Fig. 23.— Middle and posterior meningeal arteries supplying the interior of the skull. 

bone, as is frequently the case, it may involve the external auditory meatus and 
bleeding from the ear will result. 

Fractures through the posterior cerebral fossa may cause bleeding into the struc- 
tures of the back of the neck. This is not common. 

Middle Meningeal Hc7norrhage. — Bleeding from the middle meningeal artery, 
epi- or extradural hemorrhage, occurs in those fractures which pass through the region 




External angular process 



Anterior branch of 
middle meningeal 



Posterior branches of 
middle meningeal 



Fig. 24.— Points of trephining for hemorrhage from the middle meningeal artery. The course of the artery has been 

marked on the outer surface of the skull. 

of the pterion This point is the junction of the coronal and sphenoparietal sutures, 
about 4 cm. ( i ^ in. ) behind and slightly above the external angular process of the 
frontal bone. The middle meningeal artery comes up through the foramen spinosum 
and then goes forward, upward, and outward to the lower anterior angle of the 



i8 APPLIED ANATOMY. 

parietal bone. It sends branches forward to the frontal region and backward to the 
parietal and temporal regions. During two to three centimetres of its course, at the 
pterion, it passes entirely through bone, and therefore if a fracture occurs at this 
point it must of necessity tear the artery. The posterior branches are not regular in 
their course, one passing backward, low down, parallel to the zygoma, and another 
higher up in the direction of the parietal eminence. The branches of the meningeal 
artery nourish the bone as well as the dura, therefore if the dura is loosened from 
the bone hemorrhage from these branches occurs. The most frequent site of middle 
meningeal hemorrhage is in the region of the pterion or temple. 

In trephining for it, the centre of the trephine is to be placed on an average of 
4 cm. ( I ^ in. ) behind the external angular process of the frontal bone, and on a 
level with the upper edge of the orbit or 4.5 cm. (i^ in.) above the zygoma. If 
the artery is not sufficiently exposed more bone is to be removed by the rongeur 




ist — olfectory 



and — optic 

3rd — oculomotor 

4th— trochlear (pathetic) 



5th — trigeminal (trifacial) 
6th— abducent 

7th— facial 

8th — auditory 

9th — glossopharyngeal 

loth— vagus (pneumogastrlc) 

nth — spinal accessory 

12th — hypoglossal 



Fig. 25. — Exit of cranial nerves at the base of the skull. 

forceps. It is in this region that epidural hemorrhages are apt to be extensive, 
because the vessels torn are the largest; but epidural hemorrhage can also occur in 
the frontal region from the anterior branches and in the parietal from the posterior. 

Trephining for bleeding from the posterior branch of the middle meningeal 
artery is somewhat uncertain. In some cases the artery runs low down, about 2 cm. 
(4/5 in.) above the zygoma and parallel to it. In other cases it runs upward and 
backward toward the parietal eminence. The trephine may be placed as high up 
as for the anterior branch of the middle meningeal artery, 4.5 cm. (i^ in.), and 
5 cm. (2 in.) farther back. This will be below and anterior to the parietal eminence 
and about midway on a line joining the parietal eminence and external auditory 
meatus. After the button of bone has been removed, additional bone may be cut 
away with the rongeur forceps until access can be had to the bleeding point (see 
page 23 for a case of rupture without fracture). 

Rupture of the large venous sinuses and of the small vessels passing between the 
bone and .dura also contribute to the formation of the clot. Owing to the firmer 



THE SKULL. 



19 



attachment of the dura mater in children, the meningeal arteries are more liable to 
be torn and cause hemorrhage than is the case in adults. For the same reason the 
blood pressure is not sufficient to dissect the dura from the skull, therefore epidural 
clots are rare. If there is a fracture, blood may collect beneath the scalp, and if an 
external wound exists, the blood will find an exit through it. 

Bleeding from the Venous Sinuses. — Bleeding may occur from the sinuses of the 
base as well as from those of the vault. In severe injuries of the vault detached frag- 
ments frequently penetrate the superior longitudinal and lateral sinuses. In these 
cases profuse bleeding occurs as soon as attempts are made to remove the loose pieces 
of bone, and it is necessary to use a packing of gauze to control it. Fractures passing 
through the petrous portion of the temporal bone wound the petrosal sinus and 
this no doubt contributes to the blood which flows from the ear. 

Emphysema is most likely to occur if the frontal air sinuses are involved, partic- 
ularly if the patient blows his nose in the 
attempt to relieve it of blood clots. Em- 
physema is not so liable to occur in cases 
of fracture involving the mastoid cells. 

Cerebrospinal fluid may escape when- 
ever the meninges are torn and the sub- 
arachnoid space is opened. It is most fre- 
quently seen in the fractures involving the 
middle fossa and passing through the in- 
ternal auditory meatus. The meninges are 
prolonged into the internal meatus, and the 
clear fluid is not infrequently seen coming 
from the ear of the injured side. Although 
the normal amount of cerebrospinal fluid 
is only about two ounces, much greater 
quantities can escape. A serous discharge, 
perhaps of several ounces, is indicative of 
a rupture into the subarachnoid space. 

Injuries to Nerves in Fracture 
of the SkulL — The nerves most often 
disturbed in injuries of the skull are the 
first, second, third, seventh, and eighth. 

The first or olfactory nerve may be 
injured directly in the line of fracture, or 

by concussion. I have had under my care two such cases in women who struck the 
occiput on an asphalt pavement in getting off backward from a moving trolley car. 
These patients left the hospital after several weeks with the sense of smell still lacking. 

Injuries to the second or optic nerve are apt to be accompanied by such severe 
injuries to other parts as to cause the death of the patient before the loss of sight is 
discovered. If the optic nerve is injured at the optic foramen, there may be impair- 
ment of sight without any intra-ocular changes to be seen with the ophthalmoscope. 
Inside of two weeks, however, the pinkish color of the disk gives way to the gray-white 
color of atrophy, and this progresses until complete. The nerve never resumes its 
functions and the patient remains blind. 

Injury of the third or oculomotor nerve has also come under my notice. In this 
the pupil of the affected eye is moderately dilated and does not respond to light. 
The ciliary muscle is supplied by the third nerve, as well as the circular fibres of the 
iris, so that the accommodation is paralyzed and, if the eye has been normal in its 
refraction, the patient will be unable to read or see objects clearly at close distances. 
The extrinsic muscles of the eye, with the exception of the superior oblique and 
external rectus, are also supplied by this nerve and the eye is therefore pulled outward 
and slightly downward, and diplopia, or double vision, may be produced. The patient 
is unable to move the eye either upward, inward, or downward. The levator palpe- 
brae muscle is also paralyzed and there is ptosis or drooping of the upper lid. The 
orbicularis palpebrarum muscle, being supplied by the seventh nerve, has its func- 
tions unimpaired, and the eyelids can be closed. 




Fig. 26.- 



-Paralysis of the facial nerve from fracture 
of base of skull (author's case). 



20 APPLIED ANATOMY. 

The fourth or paJietic Jierve is almost never injured. It supplies the superior 
oblique muscle, which turns the eyeball down and slightly outward. Paralysis of it 
causes diplopia, with the image of the injured eye below that of the sound eye and 
tilted to the right, if the right eye is affected, and to the left, if the left is affected. 

T\\ejifth or trifacial nerve is very rarely injured. If it is completely paralyzed 
there will be loss of motion in the muscles of mastication and loss of sensation over 
the side of the face, of one-half of the interior of the mouth, of the side and front of 
the tongue, and of the eye. 

The sixth or abduceiit nerve supplies the external rectus muscle of the eye, and 
if paralyzed causes internal strabismus, the eye looking inward. While more often 
paralyzed than the fourth and fifth, it is not so frequently paralyzed as are the two 
following nerves. 

The seventh ox facial nerve is the one most frequently injured in fractures of the 
skull. It enters the internal auditory meatus with the auditory nerve, being above 
it. Reaching the end of the meatus internus, it enters the canal of Fallopius and 
emerges from the temporal bone at the stylomastoid foramen. When paralyzed, the 
face on that side remains motionless, the eye cannot be closed, and food accumulates 
between the teeth and cheek. The corner of the mouth is drawn to the opposite 
side when the muscles of the face are contracted. 

The internal auditory meatus contains a prolongation of the dura mater and 
arachnoid, so that a fracture through it would open the subarachnoid space and allow 
the cerebrospinal fluid to escape. In these cases there is also usually bleeding from 
the ear. Escape of cerebrospinal fluid is to be distinguished from a flow of serum by 
its greater quantity, sometimes many ounces escaping. 

The eighth or auditory nerve is injured with moderate frequency, but perhaps 
hardly so often as supposed, for the deafness which sometimes follows injuries to the 
head may not be caused by an injury to the auditory nerve itself, but is rather due to 
the injury done by concussion of the brain in the region of the first temporal con- 
volution, or possibly to the tympanum. The eighth nerve is embraced in the same 
extension of the meninges into the internal meatus as is the seventh, and injuries to it 
may also be accompanied with loss of cerebrospinal fluid. The seventh and eighth 
are said to be more often paralyzed than any of the other nerves. 

Injuries to the remaining four nerves — the glossopharyngeal, vagus, spinal 
accessory, and hypoglossal — have been observed too rarely to require any extensive 
attention here. 

THE MENINGES. 

The meninges of the brain consist of three separate coverings: the outer being 
the dura mater, the middle the arachnoid, and the inner the pia mater. 

The dura mater or fibrous covering of the brain is tough and strong and 
intended to protect it. Injuries of the skull without a laceration of this membrane 
are much less serious than when it is involved. When it is torn, not only is the 
brain beneath likely to be injured, but an opportunity is given for infection to enter 
and affect the brain itself and even produce a hernia cerebri or hernial protrusion of 
brain matter through the rent. 

The dura mater is composed of two layers, the outer one acting as a periosteum 
to the bones. The two layers are in most places closely united, but at others they 
separate and form sinuses or canals, connected with the veins and carrying venous 
blood. They^/x cerebri {Y\^. 27) which is the fibrous partition separating the hemi- 
spheres of the brain from one another, as well as the tentoriiun, which separates the 
cerebrum from the cerebellum, is formed by the inner layer of the dura mater project- 
ing inward and forming a partition. On the floor of the skull, the dura mater accom- 
panies the nerves and gives them a sheath. The Gasserian ganglion of the fifth 
nerve is held in a pocket formed by the separation of the two layers of the dura mater. 

The cerebral blood sinuses have already been considered. The dura is nour- 
ished by the meningeal arteries ; bleeding from these has already been alluded to . 
(page 17). Thin fibres of the dura pass to the bone, also branches of the meningeal 
arteries and veins pass to the inner table and diploe: these all serve to fasten the 



THE MENINGES. 



21 



dura to the skull. This attachment is firmest on the base of the skull. On the vault, 
after an opening has been made through the skull by a trephine, the dura can be 
readily separated from the bone by means of a thin, flat, steel spatula. On account of 
the small size of the vessels passing from the dura to the bone, this procedure is not 
usually accompanied by much hemorrhage. In separating the dura from the base ot 
the skull, as is done in operations on the Gasserian ganglion, the bleeding from this 
source is often quite free. The dura is liable to be torn in lifting it from the bone 
if the greatest care is not exercised. 

The middle meningeal artery, at a distance of 4 cm. (i}4 in. ) posterior to the 
angular process of the frontal bone and about the same above the zygoma, usually 
passes within the bone for a distance of i 01 2 cm. Therefore, in operating in the 
temporal region, if the dura is detached the vessel will be torn and free bleeding will 




Fig. 27. — Vault of the skull opened and brain removed, showing the lalx cerebri and tentorium. 



follow. The vessel is liable to be torn in endeavoring to remove bony fragments in 
fractures of this region. The dura is also more firmly attached in the median line; 
and on each side of the median line are the depressions in the parietal bone which 
lodge the Pacchionian bodies. The largest are usually located at a distance of from 
2 to 5 cm. posterior to a line drawn across the skull from one external auditory 
meatus to the other. They are prolongations from the arachnoid and are surrounded 
by blood from the longitudinal sinus. 

The Arachnoid — also called Arachnopia or Parietal Layer of the Pia. 
— The arachnoid is a thin fibrous membrane, which passes over the convolutions of 
the brain and does not dip into the sulci between. It is more marked on the base 
than on the convexity of the brain. It is not attached to the dura above, and this 
subdural space, while moist, contains little or no free fluid. Hemorrhages do not 
occur into this space unless the membranes are torn, because the bleeding from the 
vessels of the dura is always epidural and the arachnoid derives its nourishment from 
the pia mater below, so that hemorrhages start beneath the arachnoid, but may rupture 
through the arachnoid into the subdural space. From its under surface, fibrils of loose 



22 APPLIED ANATOMY. 

tissue pass to the pia mater; the space between the fibrous layer of the arachnoid above 
and the pia mater and convolutions of the brain below is called the siibarachnoid 
space. This is a lymph space and contains the cerebrospinal fiuid. This fluid is 
normally about 60 c.c. (2 ounces) in quantity, but in injuries to the brain in which 
the subarachnoid space is opened, the fluid is secreted and discharged very rapidly. 

As has already been mentioned, the arachnoid sends a prolongation into the 
internal auditory meatus, hence a fracture through it would open the subarachnoid 
space. This space communicates with the ventricles of the brain through three 
openings in the pia mater at the lower back portion of the roof of the fourth ventricle; 
these are called the foramina of Mage7idie, Key, and Retzms. The cerebrospinal 
fluid extends down the spinal canal and can be removed by tapping with a trochar, as 
is practised in the lumbar region. 

The Pia Mater. — The net-work of vessels, with their supporting membrane, 
which covers the convolutions of the brain, forms the pia mater. The fibrils of con- 
nective tissue supporting the vessels are attached to the fibrous layer of the arachnoid 
above, so that the pia and arachnoid are in reality continuous structures. The spaces 
between these fibrils are often quite large and communicate with each other, forming 
the subarachnoid space. The lower portions of these fibrils are united and form a 
basement membrane which lies directly on the convolutions of the brain and dips into 
the sulci. The blood-vessels are intimately connected with this lower pial membrane 
and not with the arachnoid above. These vessels penetrate into the substance of the 
brain, carrying with them a covering or sheath of pia mater. This is called the/'^r/- 
vascular lymph sheath and, of course, communicates with the subarachnoid space 
above. These vessels nourish the brain. The perivascular lymph sheaths are also 
said to form capsules around the great pyramidal and large glial cells of the cortex. 

AFFECTIONS OF THE MEMBRANES OF THE BRAIN. 

Both the dura mater and the pia mater are subject to inflammation and hemor- 
rhages. The arachnoid being practically a part of the pia mater is involved in its 
diseases, so that no mention is made of it as being separately affected. 

Inflammation of the Dura Mater; Pachymeningitis. — The outer surface 
or inner surface of the dura may be involved, constituting pachymeningitis externa 
or interna. 

Pachymeningitis Externa. — The external surface is most often affected by 
injuries from without, or by extension of diseases from the adjoining bone. In cases 
of fracture the inflammation which accompanies healing frequently causes the dura 
to become densely adherent to the overlying skull. This is noticed particularly when 
trephining operations are performed for the relief of focal or Jacksonian epilepsy. 
Should the fracture be compound or open, the occurrence of sepsis will tend to 
involve the adjacent dura mater. The same occurs in cases of necrosis. Syphilitic 
disease of the bones is most apt to affect the vault of the skull, while the dura 
towards the sides and base is most often involved by suppurative ear disease. The 
dura also becomes involved in tumors and gummata. 

Inflammation of the dura is not apt to be a marked disease. It is a very dense 
membrane with few blood-vessels, therefore it is quite resistant to inflammatory proc- 
esses. It acts as a barrier to the farther extension of an inflammation rather than 
as a carrier. Therefore w^e see epidural collections of pus existing for a considerable 
time without brain symptoms super\'ening. 

The dura mater contains the large cerebral venous sinuses, and when the inflam- 
matory process occurs in those regions, the sinuses become inflamed and thrombosis or 
clotting occurs. The clot becoming infected breaks down, the pus and debris pour into 
the general circulation, and general septicaemia, and even death, is caused. This is most 
liable to occur in the region of the ear, where the infection is apt to reach and involve 
the lateral (transverse) sinus. Infection of the longitudinal sinus is much more rare. 

Pachyme?iingitis interyia is an inflammation of the inner surface of the dura. It 
occurs, to a certain extent, in cases of gumma or other new growths involving the inner 
surface of the dura or extending from the pia mater below. The name pachymeningitis 
interna, also called haemorrhagica, is usually restricted to a chronic inflammation of 



THE iMENINGES. 



23 



le inner surface of the dura, with the formation of one or more hemorrhagic mem- 
branous layers. Adhesions to the pia do not occur. The disease has been seen in 
purpuric and infectious diseases, as well as in alcoholic and demented individuals. 

Dural Hemorrhage. — Hemorrhage arising from injury to the dura through 
fracture of the skull has already been discussed (see page 18). Epidural hemorrhage 
may, however, occur from an injury to the skull and detach the membrane from 
the bone without a fracture being present. The possibility of this occurring is proved 
by the remarkable case reported by Dr. J. S. Horsley {New York Med. Joiir., Feb. 
9, 190 1). A man was struck on the head with a wooden club. He was momen- 
tarily stunned, but soon recovered and felt perfectly well. An hour and a half later he 
became drowsy, and in a few hours was in a state of stupor. The right side of the 
body and face was paralyzed, and the left arm and leg were in constant jerking con- 
vulsions. He was trephined over the left parietal eminence and four to six ounces 
of blood clot removed. There w'as no evidence of fracture or wound of the dura. 
Recovery was prompt. There have also been other recorded cases. 

In operations involving the separation of the dura from the bone, bleeding may 
be quite free. This comes from rupture of the veins passing from the bone to the 
dura, and sometimes from the rupture of a vein passing over or in the dura itself. 

Subdural hemorrhages always originate from the pia mater. 

Inflammation of the Pia Mater; Meningitis. — This, when not of a tuber- 
culous character is called leptomeningitis. It is commonly known as inflammation of 
the brain, or meningitis. The pia mater of the brain being directly continuous with 
that of the spinal cord, inflammations of the former extend to and involve the latter in 
about one-third of the cases. The disease is then called cerebrospinal meningitis. 

Infection is the usual cause of leptomeningitis. Direct injury to the membranes 
and their bony envelopes may cause it, but it occurs usually through some secondary 
avenue of infection. Thus, it may follow fractures opening into the mouth, nose, 
the various accessory bony sinuses, ear, etc. The infection may, however, not be 
traumatic, but occur through the blood, following or accompanying the various 
infectious diseases. Owing to the fact of the pia lying on the brain substance, and 
its vessels with their perivascular sheaths penetrating it, the disease naturally tends 
to involve the brain, if it is very severe or long standing. If such is the case, the 
affection is called cerebritis or encephalitis. 

The inflammation may be serous, plastic, or even purulent. The pia mater being 
continuous with the choroid plexuses, the ventricles may be dilated by the increased 
fluid. The infection may follow the vessels into the brain and produce brain abscess. 
The efifusion being often localized at the base of the brain interferes with the functions 
of the cerebral nerves. The first, or olfactory, is comparatively rarely affected. The 
optic, or second, is more often so, producing intolerance of light. There may be 
choked disk, and I have even seen a case in which there was total blindness without 
any change being visible in the nerve by means of ophthalmoscopy. In this case 
atrophy of the disk soon followed. The third, or motor oculi, according to Church 
and Peterson, is almost always affected. This would be shown by strabismus, diplopia, 
and changes in the pupil. Facial paralysis, from implication of the seventh nerve, is 
sometimes seen, and the auditory, or eighth, may also be affected. Involvement of 
the hypoglossal or twelfth nerve, will be shown by de\'iation of the tongue. The 
origin of the cranial nerves from the base of the brain is shown in Fig. 28. 

Tuberculous Meningitis. — In this form of meningitis the infection comes through 
the blood, and the tuberculous lesions follow the vessels. They are most marked on 
the base of the brain, involving the circle of Willis and the Sylvian fissure. The 
infection follows the vessels of the pia mater through the transverse fissure into the 
ventricles. The effusion accumulating in the ventricles has given rise to the name 
acute hydrocephalics. It also follows the perivascular sheaths of the smaller vessels 
into the brain substance, producing a cerebritis; thus it is seen how a knowledge of 
the circulation of the brain explains the location of the lesions. 

The exudate involving the nerves of the base of the brain produces correspond- 
ing symptoms by interfering with their function. 

Pial Hemorrhage. — Meningeal hemorrhage may be either subarachnoid or 
subdural. If the hemorrhage has not been violent, it spreads out under the arach- 



24 



APPLIED ANATOMY. 



noid in the subarachnoid space. If, however, the blood has escaped with consider- 
able force, it tears its way through the arachnoid and spreads in the subdural, as well 
as through the subarachnoid space. The origin of this form of hemorrhage is the 
vessels of the pia mater. The arachnoid does not give rise to hemorrhages, neither 
does the inner surface of the dura, unless it has previously been the seat of pachy- 
meningitis interna. 

The hemorrhage is the result either of injury or disease. In children it is 
usually due to injury; in adults to either injury or disease. These hemorrhages are 
most common in infancy and occur in childbirth. They are due apparently to 
hard, protracted labor or injury done to the child in effecting delivery by forceps, 
etc. , especially in infants born before full term. They are a cause of idiocy and the 
cerebral palsies of childhood. These hemorrhages in the new-born have been 




Olfactory tract 
Optic nerve 
Optic chiasm 
Optic tract 

3rd — motor 

oculi 



4th — trochlear 
(pathetic) 

5th — trigemi- 
.^ " iial (trifacial) 



6th — abducent 

7th — facial 
8th — auditory 

9th — glosso- 
phar\iigeal 
10th — vagus 
(pueumogas- 
tric) 

nth — spinal 
accessory 



1 2th — h ypoglossal 



Fig. 28. — Base of brain, showing exit of cranial nerves. 



recognized by the convulsions they produce, and successful operations have been 
performed for their relief (see Harvey Gushing — "Surgical Intervention for the 
Intracranial Hemorrhages of the New-born" — Am. Jour. Med. Set., October, 1905). 
Injuries received later in life from blows on the head often produce subdural or pial 
hemorrhages, without breaking the overlying bone. They are found either at the site 
of impact or on the side opposite that on which the blow was received, the latter being 
produced by contre-coup. When pial hemorrhage occurs from disease, it is usually 
from rupture of an aneurism of one of the vessels of the pia mater. If it does not break 
through the arachnoid into the subdural space, it may spread over a considerable 
portion of the cerebral cortex, especially filling the sulci. Unless the quantity is quite 
large, so that it interferes with the motor area, hemiplegia will not occur. Convulsions 
may occasionally occur from irritation of the cortex. Blood in the subdural space 
may travel along the base of the brain and into the sheath of the optic nerve. 



THE BRAIN. 



25 



THE BRAIN. 

The affections of the brain of most anatomical interest are those mvolving its 
circulation, the motor areas, and the motor paths. Paralyses may arise from (a) 
interference with the motor areas in the cortex by hemorrhages, injuries, or tumors; 
{b) destruction of the motor paths from the cortex to their point of exit from the 
brain; (c) injury of the nerves at their exit from the brain. 

Disturbances of the circulation may be either of the nature of anaemia or ischse- 
mia, causing softening, or of congestion, causing apoplexy. 

Tumors of the brain interfere with the functions of the part in which they are 
located, as do also wounds. In all of these a knowledge of brain localization is 
essential. 

THE CIRCULATION OF THE BRAIN. 

The blood reaches the brain by means of the two internal carotid and the two 
vertebral arteries. The vertebrals enter through the foramen magnum and unite to 



/ 




A. conimuiiicans antericr 



A. cerebri anterior 



A. carotis interna 

A rerebri media 

A. conimunicans posterior 

A. anterolateral 

A. choroidea 

A. cerebri posterior 



A. basilaris 



A vertebralis 



Fig. 29. — Circulus arteriosus or circle of Willis. 

form the basilar, which at the upper border of the pons divides into the two pos- 
terior cerebrals. These give off two small branches which go to the internal carotids; 
they are the posterior communicating arteries. The carotids divide into the anterior 
and middle cerebral arteries, the anterior communicating with one another by means 
of the anterior communicating artery. Thus we have the circle of Willis {circulus 
arteriosus^, formed hy Xk^o. posterior cerebral, posterior communicating, internal car- 
otid, anterior cerebral, and anterior comniunicating arteries on each side. 

The blood supply of the brain is divided into an anterior division, furnished by 
the carotids, and a posterior division, supplied through the basilar and posterior 
cerebrals. The communication branch running between these two sets of vessels is 
so ?mall that if either is occluded the supply of blood is practically cut off from that 
point and ischaemia results, at least in most cases. 

The anterior division is subdivided into a right and a left half by the two carotid 



26 



APPLIED ANATOMY. 



arteries. These communicate across the median Hne through the anterior cerebral 
and anterior communicating. Here again the anterior communicating branch is so 
small that it is sometimes unable to furnish blood to the opposite side of the brain 




Optic nerve 

Ophthalmic artery 
Third nerve 

Fourth nerve 

Pphthalmic branch — 5th nerve 
.Sixth nerve 
Internal carotid artery 

Maxillary branch— 5th nerve 

Mandibular branch — 5th 
nerve 

Gasserian ganglion 
turned forward 

Internal jugular 
vein 



Fig. 30. — The internal carotid artery in its course through the skull, showing its relations to the jugular vein and 
cranial nerves. The Gasserian ganglion has been raised from its bed and turned forward. 

when the carotid supply of one side is shut off. This may cause syncope, stupor 
or delirium, hemiplegia, and often softening and death. These results have not 



A. cerebri anterior 




A. cerebri media 



A. cerebri posterior 
Fig. 31. — Distribution of the A. cerebri anterior and A. cerebri posterior on the medial surface of the brain. 

infrequently followed ligation of the carotid artery in cases of aneurism. Obstruc- 
tion of one vertebral artery would produce no effect because circulation would 
be restored by the other vertebral through the basilar. 



THE BRAIN. 



27 



Internal Carotid Artery. — The internal carotid artery (Fig. 30) enters the 
petrous portion of the temporal bone, then turns inward and upward through the for- 
amen lacerum medium, then forward through the caxernous sinus and finally turning 

A. cerebri anterior 



issura parieto-occipitalis 



A. cerebri pos- 
terior 




A. cerebri media 



Fig. 32. — Distribution of the A. cerebri anterior, A. cerebri posterior, and A. cerebri media on the lateral 

surface of the brain. 

upward gives off the ophthalmic artery; it then pierces the dura mater just behind 
the anterior clinoid process, where, after giving ofi the posterior communicating 
and anterior choroid, it divides into the anterior and middle cerebral arteries. ■• 



A. communicans anterior 

A. cerebri anterior 

A. carotis interna 

A. cerebri media 

A. choroid anterior 

A. communicans posterior 



A. cerebri posterior 



Temporal lobe 




enticulostriate 



Fig. 33. — Arteries of the base of the brain, especially the branches of the middle cerebral giving rise to apoplexy. 



Anterior Cerebral Artery. — The anterior cerebral (Fig. 31) passes forward and 
inward over the anterior perforated space, between the olfactory and optic nerves, to 
the median fissure. It gives of? the anterior communicating artery at this point, which 
joins the anterior cerebral of the opposite side. The main trunk then runs upward 



28 



APPLIED ANATOMY. 



In the longitudinal fissure on the corpus callosum, giving branches to the frontal and 
parietal lobes, and finally anastomoses at the posterior end of the corpus callosum 
with the posterior cerebral. This shows the wide extent of brain tissue on the medial 
surface of the brain which would be affected by the blocking of this vessel by an 
embolus. 

The terminal branches of the anterior cerebral spread laterally over the surface 
of the brain (Fig. 32) outward from the longitudinal fissure for a short distance, 
about 2 cm. As it crosses the anterior perforated space, it gives oH the antero- 
median perforating (ganglionic) arteries which pierce the lamina cinerea to supply 
the anterior portion of the caudate nucleus above. 

Middle Cerebral Artery, — The middle cerebral artery passes upward and 
outward in the fissure of Sylvius, dividing, when opposite the island of Reil, into the 
branches which supply the cortex of the brain (see Fig. 32). On its way toward 




Degenerative area 

Corpus callosum 

Nucleus caudatus 
Apoplectic area 
Internal capsu'.e 

Nucleus lentiformis 



Crura cerebri 



i Medulla oblongata 

V^— — Decussation 



Fig. 34. — Showing the degenerative and apoplectic areas of the brain and the course pursued by the motor 
fibres from the cortex, through the niternal capsule, crura, pons, and medulla to the decussation, where they 
cross the median line to supply the opposite side of the body. 

the island of Reil, at the commencement of the fissure of Sylvius, many small straight 
branches enter the brain substance to supply the basal ganglia. Two or three supply 
the caudate nucleus, others, called the anterolateral perforating (ganglionic), enter 
the anterior perforated space to supply the lenticulostriate ganglion and the anterior 
portion of the thalamus. One of the largest of these arteries, the lenticulostriate, has 
been called the artery of cerebral hemorrhage, by Charcot, on account of the frequency 
with which it is found ruptured in cases of apoplexy (Fig. 33). 

Anterior Choroid. — The anterior choroid artery comes sometimes from the 
internal carotid and sometimes from the middle cerebral. It passes backward and 
outward on the optic tract and crus cerebri and enters the transverse fissure at the 
descending horn of the lateral ventricle. It ends in the choroid plexus (see Fig. 33). 

Posterior Cerebral Artery. — The posterior cerebral artery passes outward over 
the crus cerebri, just above the pons, to the under surface of the posterior portion of 
the cerebral hemisphere. Before it receives the posterior communicating artery it gives 
off the posteromedian perforating (ganglionic) arteries, which enter the posterior 
perforated space to supply the thalamus and third ventricle. Just beyond the poste- 



THE BRAIN. 



29 



nor communicating artery it gives off the posterolateral perforating (ganglionic; 
arteries, which supply the posterior portion of the optic thalamus, crus cerebri, and 



Velum interpositum 
Middle commissure / 
Ciioroid plexus 
Foramen of Monro 
Septum lucidum 



Posterior commissure 

Pineal body 

Splenium 




Corpora quadri- 
gemina 



Anterior commissure 
Optic nerve 

Optic chiasm 

Pituitary body 



Mammillary body 

Aqueduct of Sylvius 



4th ventricle 
Fig. 35. -Medial section of the brain. 



corpora quadrigemina. The branches to the cortex supply a small portion of the 
inferior surface of the temporosphenoidal lobe and the occipital lobe as seen in 
Figs. 31 and 32. 



Corpus callosum 

Septum lucidum 
Caudate nucleus 



Choroid plexus 
Velum interpositum 
Veins of Galen 




Fig. 36. — Horizontal section of brain ; the corpus callosum and fornix have been removed, exposing the lateral 
ventricles, with the caudate nuclei projecting into them anteriorly and the velum interpositum farther back, with 
the choroid plexus at the sides and the veins of Galen nearer tfie middle line. The lateral ventricles in this brain 
are somewhat larger than usual. 



30 



APPLIED ANATOMY. 



Cerebral Softening. — This occurs in the young from embohsm ; it then affects 
the cortex, but the more common variety is caused by thrombosis in arteries which 
are diseased, usually in the aged. The part farthest from the source of blood 
supply is the most apt to suffer, therefore we find it occurring most frequently in 
the anterior capsuloganglionic region, just above the usual site of apoplexy (Fig. 34). 
The affected area will be seen to be most remote from both the cortical and basal blood 
supply. The perforating arteries supplying this region are in the nature of terminal 
branches and do not anastomose to any extent either with each other or with the 
branches coming from the cortex, hence their occlusion inflicts irreparable damage. 

Apoplexy. — By apoplexy is meant the rupture of a blood-vessel with conse- 
quent extravasation of blood, either in or on the brain. It may occur in any portion 
of the brain, and either from the arteries of the base^ or from the smaller arteries of 



Lateral ventricle 



Caudate nucleus 

Internal capsule, 
anterior limb 

Lenticular nucleus - 

Claustrum 

Internal rapsiile, 
posterior limb 

Thalamus 

Corpora quadrigemina 

Lateral ventricle, 
inferior horn 




Septum lucidum 

Fornix — anterior pillar 



Fig. 37. — Horizontal section of the brain, showing the internal capsule and its relation to the lateral ventricles. 



the cortex. The former is the more frequent. The arteries that most often rupture 
are the branches of the middle cerebral which enter the anterior perforated space, 
especially its outer portion. One of the largest of these anterolateral arteries, as has 
already been mentioned, known as the lenticulostriate, has been called by Chaicot 
the artery of cerebral hemorrhage. 

The portions of the brain usually affected are the posterior portion of the len- 
ticular nucleus, internal capsule, and surrounding parts. 

Figure 35 is a medial section of the brain, giving a lateral view of the ventricles. 

Figure 36 is a horizontal transverse section of the brain, opening up the ventri- 
cles. In front are seen the two lateral ve7itricles, separated by the septtivi hicidum. 
The cavity shown in the septum lucidum is the so-called y?/?/^ ventricle. The round 
body bulging into the lateral ventricle and forming its floor is the caudate nucleus 
portion of the corpus striatum. The third ventricle is posterior and below the lateral 
ventricles, and extends from the septum lucidum in front to the posterior pillars of 
the fornix behind. It extends from side to side as one large cavity with no median 
partition. Bulging into the third ventricle on each side are the {optic) thalami. 
They are separated from the corpora striata by some white fibres, the tccnia semicircu- 
laris. To the inner side of the taenia semicircularis is seen the choroid plexus, which 



THE BRAIN. 



31 



runs down anteriorly over the thalamus to the foramen of Monro, through which 
it enters the lateral ventricle. Two large veins, the veiris of Galen, pass down 
near the middle line of the third ventricle to empty into the straight sinus. Pos- 
teriorly, the choroid plexus follows the. descending horn of the lateral ventricles. 
The choroid plexus hangs from the under surface of the velum interpositum, which 
is a fold of the pia mater entering through the transverse fissure. The veins of Galen 
run between the two layers of the velum interpositum. 

Turning now to Fig. 37, showing a somewhat deeper transverse horizontal 
section, running through the corpus striatum and thalamus, it will be seen that to 
the outer side of the corpus striatum and thalamus is a white layer constitut- 
ing the internal capsule. It divides the corpus striatum into two parts, one to its 
inner side, which projects into the lateral ventricle, called the caudate nucleus, and 




Degenerative area 

Corpus callosum 

Nucleus caudatus 
Apoplectic area 
Internal capsule 

Nucleus lentiformis 



Crura cerebri 



Medulla cblong^ata 
Decussation 



38-— Showmw the degenerative and apoplectic areas of the brain and the course pursued by the motor 
fibres from the cortex, throuj^^h the niternal capsule, crura, pons, and medulla to the decussation, where they 
cross the median line to supply the opposite side of the body. 

the other to its outer side, called the lenticular nucleus. To the inner side of the 
posterior portion of the lenticular nucleus and internal capsule is seen the thal- 
amus. To the outer side of the lenticular nucleus one sees other white fibres called 
the external capsule. An apoplectic hemorrhage occurring in the lenticular nucleus 
or internal capsule may push forward and rupture into the lateral ventricle. It may 
go backward and involve the anterior portion of the thalamus and burst into 
the third ventricle, and if it extends outward it involves the external capsule. Some- 
times, if the hemorrhage is low down, it ruptures downward through the base of the 
brain, showing itself, of course, at the anterior perforated space. Fig. 33 shows these 
structures as seen in a medial section of the brain. 

In Fig. 38 there is a coronal transverse section of the brain, showing the course 
of fibres of the internal capsule from the cortex of the brain through the corpus 
striatum, between the lenticular and caudate nuclei : then, forming the cr7is cerebri, 
the fibres pass through the pons and medulla to enter the spine, decussate, and 
pass to the extremities. This constitutes the motor pathway from the cortex to the 
extremities, and when it is injured in apoplexy, the extremities of the opposite side 
are paralyzed. 



32 



APPLIED ANATOMY. 



Clot in pons, upper 
f — portion 

'i 

Clot in lower 
portion 

Facial nerve 



Hemorrhage into the Pons — Crossed Paralysis, — Apoplexy may also occur 
in other portions of the brain. It may occur in the pons (see Fig. 39). This produces 

two different sets of symptoms, accord- 
W^ 1 1 ing to its location, which is due to 

the fact that the fibres of the seventh 
or facial nerve, in their passage from 
the cortex to the face, decussate in the 
pons. If a small hemorrhage occurs 
into the upper portion of the pons, it 
will destroy the motor fibres to the 
face and the extremities of the oppo- 
site side. If, however, the hemor- 
rhage is below the point of decussa- 
tion, the side of the face on the side of 
the lesion will be paralyzed and the 
extremities of the opposite side, thus 
producing what is known as crossed 
paralysis, that is, a paralysis of the face 
on one side and of the extremities on 
the other. 

Cortical Apoplexy. — Hemor- 
rhages of the cortex are apt to be less 
in extent and more localized on ac- 
count of the smaller size of the ves- 
sels affected. They either destroy or 
irritate the bram at the site of injury, and produce, if they involve certain areas 
of the brain, definite peripheral symptoms which serve to indicate the seat of lesion. 




Spinal nerves 



Fig. 39. — Diagram illustrative of crossed paralysis. A 
clot in the upper portion of the pons causes paralysis of the 
muscles of the face and extremities of the same side of the 
body. A clot in the lower portion of the pons causes paraly- 
sis of one side of the face and the extremities of the opposite 
side of the body. 



THE CEREBRAL LOBES. 

Each cerebral hemisphere is composed of five lobes, called the/ro?ifa/, parietal, 
occipital, temporosphenoidal, and central, or isla^id of Reil. 

The frontal lobe comprises the anterior portion of the brain, as far back as the 
fissure of Rolando or central sulcus, and as far toward the base as the fissure of Sylvius. 



us parietalis 



lobus frontalis 




Lobus occipitalis 



Lobus centralis or insula 



Lobus temporalis 



Fig. 40. — Lobes of the brain. 

The parietal lobe extends from the fissure of Rolando (central sulcus) in front 
to the parieto-occipital fissure behind. Below, it is limited anteriorly by the fissure 
of Sylvius, while its posterior portion merges into the temporosphenoidal lobe. 

The occipital lobe extends posteriorly from a line joining the occipitoparietal 
fissure above to the pre-occipital notch below. 

The temporosphenoidal lobe consists of that portion of the brain below the 
fissure of Sylvius, as far back as the pre-occipital notch. It occupies the middle 
fossa of the skull. 



THE BRAIN. 



33 



The central lobe or island of Reil, also called the insula, consists of five 
to seven convolutions which radiate upward; it can be seen by separating the two 
sides of the anterior portion of the fissure of Sylvius. 

THE FISSURES AND CONVOLUTIONS OF THE BRAIN. 

The surface of the brain is wrinkled or thrown into folds, producing elevations 
and depressions. The elevations are called convolutions or gyri, and the depres- 
sions, fissures or sulci. 

The fissures are called main or subsidiary fissures, according to their impor- 
tance. The five main fissures are the longitudinal fissure, which separates the 
hemispheres; the transverse fissure, which separates the cerebrum and cerebellum 
and communicates with the third ventricle; the fissure of Sylviiis ; the fissure of 
Rolando, or central fissure, and the parieto-occipital fissure. 



THE LATERAL SURFACE OF THE HEMISPHERES. 

The frontal lobe has a superior, an inferior, and a precentral sulcus. The first 
two divide the anterior portion into the stiperior, viiddle, and inferior frontal convo- 



Sulcus praecentralis 

\ 
\ 



Sulcus centralis (Rolandi) 
Sulcus post centralis 

^Sulcus interparietalis 



Sulcus frontalis 
superior 



Sulcus frontalis 
inferior 




Fissura parieto- 
occipitalis 



Sulcus occipitalis 
transversus 



Sulcus occipitalis 
lateralis 



Fissura lateralis (Sylvii 

Sulcus temporalis superior 

Sulcus temporalis medius 

Fig. 41. — Fissures, sulci, and gyri (convolutions) of the lateral surface of the cerebral hemisphere. 

lutions. That portion of the inferior or third left frontal convolution which surrounds 
the ascending limb of the fissure of Sylvius is called Brocd' s convolution, and is 
the centre for speech. Posterior to these and running upward and backward, form- 
ing the anterior wall of the central fissure, is the precentral or ascendiiig frontal 
convolution. 

The convolution forming the anterior extremity of the parietal lobe and the 
posterior wall of the central sulcus or fissure of Rolando is called the postcentral or 
ascendiiig parietal convolutio7i. Immediately behind it is the postcentral or inter- 
parietal sulcus. The upper portion of this sulcus divides, one branch going up- 
ward and one backward. Immediately above the posterior branch is the superior 
parietal gyrus or lobule, and below it and surrounding the posterior extremity of the 
fissure of Sylvius is the supramarginal gyriis. Posterior to the supramarginal gyrus 
and surrounding the posterior extremity of the superior temporal, or temporosphe- 
noidal sulcus is the convolution known as the a^igular gyriis. 

The occipital lobe on its convex surface is divided into superior and inferior 
occipital convolutions by the lateral occipital sulcus. 

The temporal or temporosphenoidal lobe is also divided into superior, middle, 
and inferior, or first, second, and third temporal convolutions hy the superior, or par- 
allel, and middle fissures. On the under surface is a fourth temporal convoltition, 
separated from the third by the inferior temporal fissure. These fissures may not be 
distinct. 



34 



APPLIED ANATOMY. 



THE MEDIAL SURFACE OF THE HEMISPHERES. 

If now the medial surface of the hemisphere, which forms one side of the longi- 
tudinal fissure, be examined, there is seen a large convolution running just above and 
parallel with the corpus callosum. It is called the gyrus cinguli (^fornicatiis). Below 
and separating it from the corpus callosum is the callosal fissure; above it is the calloso- 
marginal fissure. The convolution above the latter, forming the margin of the hem- 
isphere, is the viarginal convohdion. The callosomarginal fissure at its posterior 
portion turns upward and ends on the margin of the hemisphere, just posterior to the 
fissure of Rolando, or central fissure, and serves to identify it. This marks the pos- 
terior limit of the frontal lobe. The posterior end of the frontal lobe surrounds the 
upper end of the central fissure and on that account is called the paracentral lobule. 
Its anterior boundary is marked by the paracentral fissure, or sulcus. Between the 
callosomarginal fissure in front and the parieto-occipital fissure behind is the parietal 
lobe, called, from its square shape on the medial surface, the quadrate lobule, or from 
being anterior to the cuneus lobule, the prectineus. Running downward and back- 



Fissura centralis 
(Rolandi) 



Sulcus cinguli (callosomarginalis) 



Fissura parieto- 
occipitalis 



Fissura calcarina 
posterior 



Fissura calcarina 
anterior 




Fissura collateralis 

Sulcus temporalis inferior 

Fig. 42.— Gyri, sulci, and fissures of the medial surface of the cerebral hemisphere. 

ward from the deeper portion of the parieto-occipital fissure is a very distinct depres- 
sion called the calcarine fissure. These two fissures include a wedge-shaped piece 
of the occipital lobe called, from its shape, the cuneus lobule. It is of interest in 
reference to the sense of sight. 



FUNCTIONS OF THE CORTEX OF THE BRAIN: 

LOCALIZATION. 



CEREBRAL 



A knowledge of the functions of the various portions of the brain is necessary 
in order to localize a diseased area. The diseases and injuries to which the brain 
is exposed oftentimes do not involve the whole brain, but only certain distinct and 
isolated parts. The brain is not a single, homogeneous organ that acts only as a 
whole; it is complex. It is composed of a number of separate parts or areas, which 
may act either singly or in conjunction with other areas. These separate areas have 
different functions, so that if the disease or injury is limited to one of them, we have 
its functions abolished, and the symptoms produced indicate the area affected. 

These areas are situated on the surface or cortex of the brain in the gray matter. 
They receive impressions from, and transmit impulses to, all parts of the body 
through the white matter or fibres of the brain. An injur}' to the cortex or gray 
matter destroys the originating and receptive centres. An injury to the white matter 
destroys the paths to and from these centres and therefore prevents them from 
receiving impressions or sending out impulses. Thus, we may have a paralysis of 
the leg and arm caused by an injury to the leg and arm centres in the cortex of 
the brain, as by a hemorrhage from a fracture, or we can have the same paralysis 



THE BRAIN. 



35 



produced by an injury to the path leading from those centres, the motor tract as it 
is called, by a hemorrhage, as from apoplexy, involving the corresponding white 
matter fibres. 

The exact localization of the functions of all parts of the brain has not been 
accomplished, but the functions of many areas have been definitely proven. In 
cases of brain tumor, abscess, hemorrhage, injury, etc. , a knowledge of these areas 
enables one to localize the seat of the lesion. 



FUNCTIONS OF THE CONVOLUTIONS ON THE SURFACE OF THE CEREBRUM. 

The frontal lobe may be conveniently divided into three areas; prefrontal, mid- 
frontal, and postfrontal. The prefrontal area embraces all the superior, middle, 
and inferior frontal convolutions, with the exception of their posterior ends. On 
the medial side it reaches to the callosomarginal fissure. The function of the pre- 
frontal area is said to be that of higher cerebration, as attention, judgment, and com- 
parison. This region, particularly the lower portion, is liable to injury, owing to its 
anterior position and to the fact that it overlies the orbit. The roof of the orbit is 
quite thin and liable to fracture by penetrating bodies, as umbrellas, canes, etc. 
Sometimes a portion of this part of the brain may be destroyed without marked 
interference with the mental qualities of the patient. This occurred in the case of a 




Fig. 43.— Diagram illustrating the probable functions of the lateral surface of the brain. 

boy who was struck in the eye by a carriage pole (personal observation). The eye 
was burst, necessitating its removal. Several pieces of the fractured bone of the 
roof of the orbit w-ere removed and brain tissue came away for several days. The 
boy recovered and for sixteen years apparently had no resulting mental deficiency. 

The midfrontal area embraces the posterior portion of the superior and 
middle convolutions, with the upper posterior portion of the inferior. It is con- 
cerned in certain movements of the eyes and lids, and also in turning the head 
toward the opposite side. This midfrontal division is the most anterior portion of 
what is called the motor area. 

Speech Centre, or Broca's Convolution. — The centre of speech is located 
in right-handed people in the posterior portion of the third left frontal convolution, 
where it arches around the ascending limb of the fissure of Sylvius. It is called 
Broca's convolution. The faculty of writing or written speech is attributed to the 
graphic centre in the posterior extremity of the second frontal convolution just above 
and behind Broca's convolution. 

The postfrontal area embraces the ascending frontal convolution in front of 
the fissure of Rolando or central fissure. It is concerned in the various movements 
of the trunk and extremities, and forms the anterior portion of the Rolandic area; 
it will be considered under that head. 

The Rolandic Area. — This is the area which gives rise to most of the voluntary 
movements of the body. When affected, it causes positive symptoms of paralysis 



36 



APPLIED ANATOMY. 



or contraction of the muscles connected with it, and is the region most frequently 
affected by injuries. This is partly due to the fact of its proximity to the middle 
meningeal artery, as a hemorrhage from that vessel produces a clot which covers 
and involves this area. 

The Rolandic area embraces the ascending frontal, or precentral, and posterior 
portion of the three frontal convolutions, the former being in front of the fissure 




Fig. 44.— Diagram illustrating the motor areas of the lateral surface of the brain. 

of Rolando, or central fissure. The fissure of Rolando passes downward and for- 
ward from the longitudinal fissure, at an angle of about 70°, nearly to the fissure of 
Sylvius, being separated from it by the joining of the ascending parietal and ascend- 




FiG. 45.— Diagram illustrating the probable functions of the gyri (convolutions) of the medial surface of the brain. 

ing frontal convolutions. Sherrington and Griinbaum have shown that the motor 
area is almost exclusively anterior to the central fissure. 

The upper portion of the motor area, near the longitudinal fissure, is concerned 
with the movements of the toes and lower extremity. The leg centres are toward 
the upper end of the central fissure; next are those of the abdomen and chest. 
The arm centres are toward the middle, and the face centres, including the larynx. 



THE BRAIN. 



37 



tongue, and platysma myoid muscle, around its lower extremity. The leg, arm, and 
face centres are, respectively, opposite the posterior extremities of the superior, 
middle, and inferior frontal convolutions. 

The upper portion of the motor area passes over the upper margin of the hemi- 
sphere and down on its medial side almost as far as the callosomarginal fissure and 
paracentral lobule. 

The Sensory Area. — The portions of the cerebrum involved in cutaneous 
and muscular sensibility embrace the posterior portion of the parietal convolutions, 
the precuneus or quadrate lobule, and gyrus fornicatus as far forward as the motor 
area on the medial aspect. 

The visual area embraces the occipital lobe, particularly its cuneus lobule, 
and region of the calcarine fissure on the medial surface of the hemisphere. The 
anterior portion of the occipital lobe and the region of the angular gyrus are con- 



Foramen interventriculare 

Conimissura niedius 



Thalamus 



Ventriculum lateralis 

Corpus striatum 

Commissura anterior 




Conimissura posterior 
Corpus pineale 



f Corpora quadrigemina 



Ventriculum quartus 
Medulla 

Fig. 46.— Foreshortened view showing corpus striatum, thalamus, corpora quadrigemina, lateral, third, and 

fourth ventricles, etc. 

earned in the more complex phenomena of sight, and their destruction produces 
word-blindness. Destruction of the centres on both sides produces what has been 
called mind-blindness, because objects can no longer be recognized. 

The Auditory Area. — The centre for hearing is located in the superior and 
middle temporosphenoidal convolutions. It requires destruction of these convo- 
lutions on both sides of the brain to produce total cerebral deafness. The memory 
or recognition of spoken words (word hearing) is apparently performed by the pos- 
terior ends of the superior and middle (ist and 2d) temporosphenoidal convolutions. 

Gustatory Area. — The sense of taste is supposed to be located on the under 
and inner surfaces of the temporosphenoidal lobe or fourth temporal convolution. 

Olfactory Area. — The sense of smell is supposed to involve the anterior portion 
of the gyrus fornicatus and the upper medial portion of the temporosphenoidal lobe. 

The cerebral areas for both smell and taste have not been as yet accurately 
determined. 

FUNCTIONS OF THE BASAL GANGLIA. 

Corpus Striatum and Thalamus. — The exact functions of the corpus stria- 
tum, embracing the caudate and lenticular nuclei, and of the thalamus are not 
known. They are most often affected in apoplexies ; lesions of the corpus striatum are 
accompanied by disturbances of motion, and those of the thalamus by disturbances of 
sensation. 



38 



APPLIED ANATOMY. 



Corpora Quadrigemina. — The anterior corpora quadrigemina are associated 
with sight, the posterior possibly with hearing and equilibrium. Note their prox- 
imity to the cerebellum. 




spinal cord 



Fig. 47. — The corona radiata or projection fibres which connect the cortex above with the thalamus, corpus striatum, 
tegmental region, pons, medulla, and spinal cord below. These fibres go to form the internal capsule. 

Crura Cerebri. — The crura cerebri transmit both sensory and motor impulses. 
Note their proximity to the third nerve, as they are apt to be involved by the 



Cerebral cortex 



same lesions, thus accounting for paralyses 
or sensory disturbances of the trunk or ex- 
tremities accompanied by ocular paralysis. 
Pons Varolii. — The pons transmits 
the motor or pyramidal tract, and also the 
fifth, sixth, and seventh nerves. Implication 
of the seventh or facial nerve, together with 
the motor tract, has already been alluded to 
(page 32). If the sixth or abducent nerve 
is involved, the external rectus muscle on 
that side will be paralyzed. If the fifth, or 
trifacial nerve is affected, irritation of its 
motor root may produce trismus or clench- 
ing of the jaws, and interference with its 
sensory root may cause anaesthesia of one 
side of the face. 

THE CORONA RADIATA, INTERNAL 
CAPSULE, AND MOTOR TRACT. 

The corona radiata is the bundle of white 
fibres which spreads out like a fan and con- 
nects the cortex of the brain with the basal 
ganglia and spinal cord. Proceeding down- 
ward from the cortex, the corona radiata be- 
comes smaller and passes, in the form of a 
band, between the lenticular nucleus on the 
outside and the caudate nucleus and thal- 
amus on the inside. This band is known 
as the internal cupsnle. It transmits in its 
anterior portion fibres from the prefrontal or 
higher psychical area; then come the motor 

paths ; and still farther back, in the posterior third of the posterior portion, sensory fibres. 
T^x^ functions of the external capside, which lies to the outer side of the lenticular 

nucleus, are not known. 





Pyramidal 

decussation 
Lateral 

pyramidal tract 
Direct 

pyramidal tract 



Spinal nerve 



Fig. 48. — Diagram showing course and decussa- 
tion of corticospinal (pyramidal) tract ; M, medulla; 
P.poiis; CP, cerebral peduncle; T, thalamus; C, L, 
caudate and lenticular nuclei ; CC, corpus callosum. 
(Piersol.) 



THE BRAIN. 



39 



The motor fibres of the ijitenial capsule pass downward through the anterior 
portion of the crus cerebri and pons into the medulla, at the lower part of which 
the majority decussate and pass into the anterior columns of the cord as the/jj'ra;«- 
idal tracts. Thus, it is seen that destruction of any portion of the motor tract, 
from the point oi pyramidal decussation below, through the internal capsule to the 
cortex above, will cause a paralysis on the opposite side of the body. 



CRANIOCEREBRAL TOPOGRAPHY. 

For the purpose of operating on the brain it is essential to know the bony land- 
marks of the skull, the lower level of the brain, and the relation which the various 
fissures and convolutions bear to the surface. 

The most important fissures are the longitudinal, Sylvian, Rola7idic, 3.nd parieto- 
occipital. If these can be properly located, the convolutions and subsidiary fissures 
can be readily filled in. 

BONY LANDMARKS. 

Nasion. — The nasofrontal suture in the median line. 

Glabella. — The smooth spot in the median line on the frontal bone between 
the superciliary ridges. It is about on a level with the upper edge of the orbit. 



Bregma 



Stephanion 



Sylvian point 
Pterion 



Lambda 




Temporal ridge 



Glabella 

External angular process 
— Nasion 
Malar tubercle 



Inion 



Asterion 



Fig. 49. — Landmarks of the skull. 



Bregma. — The point in the midline where the sagittal and coronal sutures 
cross. It corresponds with the anterior fontanelle in the infant. 

Lambda. — The point of meeting of the sagittal and lambdoid sutures. It is 
about 6 cm. (2 ^^ in. ) above the occipital protuberance. 

Inion. — The external occipital protuberance. 

Pterion. — This name was given by P. Broca to the point where the frontal, 
parietal, and sphenoid bones meet in the region of the temple. It is about 2.5 cm. 
( I in. ) behind the angular process and should not be confounded with the Sylvian 
point, which is 1.5 cm. (S/^ in.) farther posterior, where the temporal, parietal, and 
sphenoid bones meet. Horsley called this latter point the pterion. The region of 
the pterion is the seat of the anterolateral fontanelle in the foetus. 

Asterion. — This lies 2 cm. (4 in.) behind the base of the mastoid process, 
where the parietal, occipital, and temporal bones meet. It is on the superior curved 
line and in fetal life forms the posterolateral fontanelle. 

Temporal Ridge. — This marks the upper attachment of the temporal fascia 
and muscle. It begins at the external angular process of the frontal bone and ends 



40 APPLIED ANATOMY. 

at the asterion. Its anterior third is well marked, but as it crosses the coronal suture 
it fades away and gradually broadens out, its upper margin being called the superior 
and its lower the inferior temporal ridge. The superior ridge marks the attachment 
of the superficial layer of the temporal fascia, the inferior, the deep layer. 

External Angular Process. — This is the outer extremity of the frontal bone, 
where it articulates with the malar. The line of the suture can be distinctly felt in 
the living. 

Malar Tubercle. — This is the small bony projection on the posterior edge of 
the malar bone, 1.25 to 2 cm. (3^ to ^ in.) below the frontomalar suture. 

Stephanion. — The point where the temporal ridge crosses the coronal suture. 

TOPOGRAPHICAL POINTS. 

Pre-auricular Point. — The depression in front of the ear and just behind the 
condyle of the lower jaw. 

Sylvian Point. — Where the anterior ascending and anterior horizontal limbs 
come off from the posterior horizontal limb of the fissure of Sylvius. It lies 4 cm. 
(i^ in. ) posterior and a little above the external angular process, at the junction of 
the parietal, sphenoid, and temporal bones. 

Superior Rolandic Point. — Where the upper end of the line marking the 
Rolandic fissure crosses the median line. 

Inferior Rolandic Point. — Where the lower end of the line marking the 
Rolandic fissure crosses the line of the Sylvian fissure. 

The Lower Level of the Brain. 

The lower level of the brain is marked by a line beginning in the median line 
I cm. (f in.) above the nasion, thence above the orbit i cm. from its edge to the 
external angular process; from here it goes to the middle of the zygoma, thence 
backward along its upper border, above the auditory meatus and along the supe- 
rior curved line to the inion (occipital protuberance). 

FISSURES AND CONVOLUTIONS. 

The conformation of the various fissures and convolutions varies so much within 
normal limits that it is not possible to outline them on the surface of the scalp or 
skull with absolute exactness. The various lines which are laid out to indicate their 
course are, therefore, only approximate, but they are sufficiently accurate for opera- 
tive purposes. To allow for variations, the openings made are usually large, and the 
motor areas are sometimes identified by the application of an electrode. 

Fissure of Sylvius (fissura cerebri lateralis). — To indicate the course of 
the Sylvian fissure, a line is drawn from the external angular process of the frontal 
bone through a point 2 cm. (^ in.) below the most prominent part of the parietal 
eminence and ending 1.5 cm. (^ in.) above the lambda. The main portion of the 
Sylvian fissure begins 2 cm. (^ in.) behind the angular process; 2 cm. farther back 
or 42 mm. ( i f^ in. ) behind the angular process is the Sylvian point, where the 
anterior horizontal and anterior ascending limbs are given ofi. From this point the 
posterior horizontal limb passes backward to 2 cm. (3/( in.) below the highest point 
of the parietal eminence and then curves upward and backward for a distance of 
1.25 cm. to 2 cm. (% to 3^ in.). 

Central Fissure, or Fissure of Rolando (sulcus centralis). — The line of 
the central fissure begins at the upper Rolandic point, 1.5 cm. (^ in.) behind the 
middle of a sagittal line passing from the glabella to the inion. It then passes 
down and forward at an angle of approximately 70° (67^, Chiene) toward the 
middle of the zygoma (Le Fort) to end at the lower Rolandic point, where it inter- 
sects the Sylvian line. It is about 9 cm. (33^ in.) long. The central fissure stops 
I cm. above the Sylvian line or fissure. 

Parieto-occipital Fissure (fissura parieto-occipitalis). — The position of 
this fissure is quite variable, an average being 1.5 cm. (^ in.) above the lambda, and 
extending 1.25 cm. (^ in.) out from the median line. It is about 6 cm. (2^^ in.) 
above the inion and on or below the line of the Sylvian fissure. 



THE BRAIN. 



41 



Subsidiary Fissures and Convolutions. 

The precentral and postcentral sulci are about 15 mm. (| in.) anterior 
and posterior to the fissure of Rolando. 

The inferior frontal convolution lies between the line of the fissure of 
Sylvius below and a line just below the temporal ridge above. 

The middle frontal convolution lies under the frontal eminence, and occu- 



Central fissure or 
fissure of Rolando 



Bregma 



Line for central or 
Rolandic fissure 

Precentral sulcus 



Interparietal 
sulcus 



Postcentral 
sulcus 



Pai ieto-occipital v-^ 

fissure 
Transverse occip- 
ital sulcus 

Parietal eminence 



Lateral occipita 
sulcus 



Inion 



Transverse or 
lateral sinus' 




Posterior horizontal limb of 
Sylvian fissure 



Line for Sylvian fissure 

Temporal ridge 
Ascending limb of 
Sylvian fissure 
Anterior horizontal limb 
Main portion of 
Sylvian fissure 



Fig. 50. — Semidiagrammatic view of head, showing relation of Rolandic and Sylvian fissures and lines. 



pies about the lower two-thirds of the distance between the temporal ridge below 
and the midline above. 

The superior frontal convolution covers about the upper one-third of the 
distance from the median line above to the temporal ridge below. 

The superior frontal sulcus passes upward from the supra-orbital notch. 

The inferior frontal sulcus runs just below the temporal ridge. 

The first or superior temporal convolution runs along the lower side of 
the fissure of Sylvius. It is about 15 mm. (f in.) wide. 

The first or superior temporal sulcus or parallel fissure runs parallel to 
the Sylvian fissure and 15 mm. below. 

The second or middle temporal convolution is wider than the first and lies 
a short distance abo\'e the level of the base of the skull. 

The middle temporal sulcus runs close above the zygoma. 

The third or inferior and the fourth temporal convolutions lie on the base 
of the brain, separated by the inferior temporal sulcus. The fourth temporal convo- 
lution has on its inner side the collateral fissure (see Fig. 42). 

The interparietal sulcus (pars horizontalis) leaves the postcentral sulcus 
near its middle and passes upward and backward to a point opposite the lambda. 

The supramarginal convolution surrounds the termination of the fissure of 
Sylvius and is, therefore, under the parietal eminence. 



42 



APPLIED ANATOMY. 



The angular gyrus surrounds the posterior end of the first temporal sulcus 
(parallel fissure) and is, therefore, 3 or 4 cm. (i^ to i)4 in.) posterior to the 
parietal eminence. 

The transverse occipital sulcus is a continuation of the interparietal sulcus 
to just beyond the parieto-occipital fissure. 

The lateral occipital sulcus lies close to the tentorium; it divides the occipi- 
tal lobe into superior and inferior convolutions. (Sometimes these two sulci divide 
the lobe into three convolutions, superior, middle, and inferior.) 

The Fissures in Children. — In childhood the fissure of Rolando is somewhat 
more vertical than in adults; the fissure of Sylvius has its point of division a little 
higher and runs up to and usually above and in front of the parietal eminence 
(Dana, Med. Record, Jan. 1889, p. 29). After the age of three years, the relative 
position of the fissure to the parietal eminence begins to approach that of the adult. 
(For variations due to age see Cunningham: " Contributions to the Surface Anatomy 
of the Cerebral Hemispheres," 1892.) 

The objects of cerebral topography are mainly to ascertain in case of injury or disease of 
the superficial structures what parts of the brain beneath are liable to be involved, and for opera- 
tive procedures, in order to expose the affected areas. 
The convolutions and sulci are so variable that all 
guides are only approximate. In order to overcome 
this defect and provide for unusual conditions, the 
openings in the skull are usually made quite large. 
The flaps of scalp and bone may even embrace the 
entire parietal bone or a quarter of one hemisphere. 
As regards the various points — the upper Rolandic 
point is generally conceded to be 15 mm. {%, to ^ in.) 
posterior to the midpoint between the glabella and 
inion. The angle which the fissure forms with the 
median line varies from 64° to 75°. Cunningham 
gives it as 70° and Arthur W. Hare as 67°. Chiene's 
method of finding the desired angle is usually accepted 
as reliable. He takes a square piece of paper and 
folds it obliquely from corner to corner making 45°, 
and then folds it a second time making 22>^°. The 
two being added together give 67^^° as the angle made 
by the fissure of Rolando with the anterior portion of 
the longitudinal fissure. 

The pterion was placed by Broca at the coronal su- 
ture. This is 15 mm. (2 in. ) in front of the Sylvian point. In several formalin hardened brains, we 
found this latter to be at the posterior angle of the pterygoid wing, and in twenty measured 
skulls the Sylvian point averaged 42 mm. 
(i^ in.) behind the angular process. Reid 
placed it at 50 mm. (2 in.) , which we think too 
much. Anderson and Makin placed it at i >^ to 
2 in. Thane and Godlee placed it 35 mm. back 
and 12 mm. up, which is just a trifle farther 
forward than we have located it. Landzert 
and Heffler gave it as at the summit of union 
of the great wing of the sphenoid with the 
temporoparietal suture, as we have given it. 
When prolonged, the Sylvian fissure some- 
times crosses the median line 1.5cm. {% in.) 
above the parieto-occipital fissure, but more 
usually we have found it to be close to the 
fissure, which agrees with Reid. The parieto- 
occipital fissure has been located by some 
authors near the lambda, but we would place it 
1.5 cm. ( % in.) above. We believe the parie- 
tal eminence to be a fairly reliable guide to the 
posterior extremity of the fissure of Sylvius. 
Method of Anderson and Makin for 
Locating the Fissures of the Brain. — For the sake of comparison the following method of 
Wm. Anderson and George Henry Makin {four. Anat. and Phys., vol. xxiii, 1888-89, p. 455) is 




Fig. 51. — Chiene's method of folding a square 
piece of paper in order to obtain an angle of 67 J^ 
degrees. 




Fig. 52. — Method of Anderson and Makin for locating the 
fissures of the brain. 



THE BRAIN. 



43 



given. Draw a mid- or sagittal line from opposite the highest point of the supra-orbital arches 
to the external occipital protuberance. From the midpoint on this line draw another to the 
pre-auricular point at the level of the upper border of the meatus. This is the frontal line. 
From the most prominent point of the external angular process draw a line to the junction of 
the middle and lower thirds of the frontal line and prolong it i}4 in. beyond. 

The Sylvian fissure begins between i}i and ij4 in. behind the angular process or jroi 
the distance between that point and the frontal line. The bifurcation is ij^ to 2 in. behind the 
angular process or yV of the distance between it and the frontal line, the fissure then runs to an 
equal distance behind the frontal line, and up for )4 in. parallel to the frontal line. The fissure 
of Rolando runs from a point }i in. behind the midsagittal point to one ^ of an inch in front of 
the intersection of the frontal line and line of the Sylvian fissure. The parieto-occipital fissure 
is j"t of the distance from the midsagittal point to the inion. It lies near the apex of the lamb- 
doid suture. 

The Lateral Ventricles. — The lateral ventricles sometimes become distended by serous or 
purulent effusions or, as in apoplexy, by blood. In order to tap them Keen (" Reference Hand- 



Fissure of Rolando 



Bregma 



Lateral ventricle 



Middle men- 
ingeal artery 
anterior 
branch 



Posterior horn of 
lateral ventricle 




Inion' 



Lateral sinus^ 



Middle meningeal artery, posterior 
branch ; inferior horn of lateral ven- 
tricle seen beneath 



Fig. 53. — Tapping the lateral ventricles and trephining for cerebral abscess. Semidiagrammaticview of head, show- 
ing relation of Rolandic and Sylvian fissures and lines. 



book of the Medical Sciences," vol. viii., p. 229) has given three points, as follows: (i) One- 
half to three-fourths of an inch (1.25 to 2 cm.) on either side of the median line and one-third 
of the distance from the glabella to the upper end of the central (Rolandic) fissure. This is 
high enough to avoid the frontal air-sinuses and is in advance of the motor area. A grooved 
director is to be thrust in the direction of the inion. The ventricle is reached at a depth of 5 to 
6.5 cm. (2 to 2>^ in.) through the first frontal convolution. (2) Midway between the mion 
and upper end of the central (Rolandic) fissure 1.25 to 2 cm. {}4 to ^ in.) from the median 
line. The director is to be thrust toward the inner end of the supra-orbital ridge of the same 
side. The ventricle will be reached at a depth of 5.5 to 7 cm. {2% to 234^ in.) from the sur- 
face. (3) Three centimetres {iX in.) behind the external auditory meatus and the same above 
Reid's base line (from the lower border of the orbit through the centre of the external auditory 
meatus). The director is to be Ihrust toward a point 6.25 to 7.5 cm. (2!^ to 3 in.) directly 
above the opposite external meatus. The ventricle will be reached 5 to 5.75 cm. (2 to 2^' in.) 
from the surface. The director passes through the second temporal convolution; this is the 
preferred method. 



44 APPLIED ANATOMY. 

Spitzka {New York Med. Jour., Feb. 2, 1901, p. 177) has pointed out how these ventricles 
vary in shape, and has given the surface relations in two brains. T. T. Wilson {Jour. Anat. and 
Phys., vol. xxviii, 1894, pp. 228-235) has described and figured them in three drawings. Spitzka 
states that the ventricles will hold about 60 c.c. of liquid. 

Cerebral Abscess. — About one-half of the abscesses of the brain occur from disease of the 
middle ear, and they are located in the temporosphenoidal lobe, in the cerebellum, or between 
the dura and petrous portion of the temporal bone. The remainder are caused either by blows 
or infection carried to the part in infectious diseases. They may, therefore, occur anywhere in 
the brain. 

When the motor areas around the fissure of Rolando are involved, the location of the 
trouble will be shown by spasm or paralysis of the corresponding muscles. If the occipital lobe 
is affected there may be disturbance of sight, as hemiopia. Involvement of the frontal lobes 
produces mental dulness, and if of the third left frontal gyrus, or Rroca's convolution there may 
be impairment of speech. Disease of the middle lobe of the cerebellum may be accompanied 
by a staggering gait. In many cases localization symptoms are rare, particularly when the 
abscess is small and located in the temporosphenoidal, parietal, or frontal lobes (see chapter on 
cerebral localization). 

Trephining. — If the abscess arises from middle-ear disease, it is customary to first open 
the mastoid antrum (see chapter on ear) and then by removing the bone above to explore the 
surface of the petrous portion of the temporal bone. To explore the temporal lobe an opening 
may be made 2.5 cm. (i in.) above the external auditory meatus and a needle passed inward, 
forward, and a little downward. 

To reach the cerebellum, the trephine should be applied 5 to 7 cm. {2 to 2}{ in.) behind 
the external meatus and well below the superior curved line. The bone at this point is apt to 
be thin and care is to be exercised not to wound the membranes. The place of trephining in 
abscesses from other causes is to be decided by the localizing symptoms. 

THE FACE. 

The face may be divided into the regions of the forehead, temples, ears, eyes, 
nose, viouth, cheek, and upper and lower jaws. The regions of the eyes, ears, nose, 
and mouth will be considered separately. Owing to the face being that part of the 
body most open to scrutiny and most difficult of concealment, deformities and dis- 
figurements of it, resulting from injury or disease, — to both of which it is prone, — 
assume a greater importance than the same troubles elsewhere. Therefore, the 
anatomy of the part should be studied with regard to the treatment of its various 
aflections from a cosmetic as well as from a curative point of view. What is usually 
regarded as constituting the face embraces the anterior half of the head as \iewed 
from the front. 

The Bones. — The bones of the head have been divided into those of the 
cranium and those of the face. The bones of the cranium are eight in number, viz. : 
the frontal, occipital, two temporals, two parietals, the sphenoid, and ethmoid. The 
bones of the face are fourteen in number, of which twelve are in pairs, viz: superior 
maxillary, malar, nasal, palate, lachrymal, and inferior turbinated bones — the vomer 
and inferior maxilla or mandible are the two single bones. 

From this it will be seen that the bony framework of the face embraces some of 
the bones of the skull, as well as those of the face proper; thus, the region of the 
forehead is formed by the frontal bone, the temporal region is formed by the frontal, 
parietal, sphenoid, and temporal bones, all belonging to the cranium, and so on. 
The palate bones are called face bones, yet they are placed deep in the region of the 
mouth and nose. 

The Soft Parts. — The soft parts are likewise of importance. The skin, thin in 
some parts, thick in others, is in many places loosely attached and has inserted in it 
the muscles of expression. It is frequently the seat of disease, particularly of cancer. 

On each side of the face are the parotid glands, often the site of inflammations. 

The blood-vessels, both arteries and veins, particularly the former, are very 
numerous and give special characters to wounds and diseases of the face. 

The nerves are abundant and complex. They are, with the exception of the 
auricidaris magnus, which comes from the second and third cervical, and to a 
slight extent the occipitalis viinor from the second cervical, all derived from the 
cranial nerves and are both motor and sensory. The paralyses and neuralgias which 



THE FACE. 



45 



affect them are among the most distressing and disfiguring of any in the body, 
wounds of the face producing paralysis of the muscles of expression. 

The relatively small size of the face in relation to the cranium in the child as 
compared to that of the adult has already been alluded to (see page 8). The 
reasons for this are evident: dentition must be complete to insure the proper 
development of the jaws; the use of the special senses and the expression of the 
emotions cause the facial muscles to develop, and this in turn causes the bones to 
which they are attached to become more rugged in outline and larger in size. In 
old age, as the teeth are lost, the jaws are diminished in size by absorption of their 
alveolar processes. 

THE FRONTAL REGION. 

The frontal region embraces that part of the face above the eyes and nose in 
front and anterior to the temples at the sides. 

The Frontal Suture. — The frontal bone develops from two centres of ossifi- 
cation, one on each side. These unite in the median line to form the frontal suture 
which joins the anterior fontanelle and 
is closed about the same time, within the 
age of two years. The suture occa- 
sionally persists through life and some- 
times the line of junction can be felt in 
the living; it should not be mistaken 
for fracture. 

The frontal eminences in the 
child are particularly prominent, the 
forehead projecting beyond the edge of 
the orbit. This makes it difficult to 
apply a bandage securely to the head 
in children unless it is twisted to draw 
in its sides. 

The superciliary ridges are 
about a centimetre above the edge of 
the orbit over its inner half. Aided by 
the hair of the eyebrows they serve 
to divert the sweat to the sides, as 
pointed out by Humphry. They are 
best developed in the adult male. 
Directly between them in the median 

line on a level with the upper edge of the orbit is a depression called the glabella. 
It is the anterior point from which measurements are taken in cerebral topography. 

Frontal Sinuses. — Beneath the superciliary ridges are the frontal air-sinuses, 
but the size of the sinuses is not necessarily proportional to that of the ridges; they 
may extend quite far back over the orbit. Fractures of the outer wall of these 
sinuses not infrequently occur without the inner table being injured. A septum 
separates one sinus from the other, not always in the median line. The lining 
membrane of these sinuses is often inflamed and suppurates, discharging pus into the 
nose. Tumors also grow in them. 

Margins of the Orbit. — At the upper and outer margin of the orbit is the 
external angular process of the frontal bone. The line of junction or suture between 
it and the malar bone can be distinctly felt in the living both on the side of the orbit 
and on the side toward the temple. This is an important landmark in cerebral 
topography, as it is used to locate the fissure of Sylvius and also the middle menin- 
geal artery. On the upper margin of the orbit at about the junction of its middle 
and inner thirds is the sicpra-orbital notch. This can usually be readily felt through 
the skin. Sometimes it is a complete foramen instead of simply a notch. It is then 
to be located by feeling on the orbital surface just behind the edge. It transmits 
the supra-orbital ner\-e and artery. 

The supra-orbital nerve, a branch of the ophthalmic division of the fifth nerve, 
is sometimes the seat of neuralgia, for which resection of the nerve is performed. 




Fig. 54.— Frontal region of a child's skull. 



46 



APPLIED ANATOMY. 



The pain is felt above the orbit radiating from the supra-orbital notch, sometimes as 
far up as the vertex. Pain is also felt on pressure over the supra-orbital notch. If 
the entire ophthalmic branch of the fifth nerve is affected, pain is felt in the eyeball 
and down the side of the nose. The incision in operating may be made at the 
lower border of the eyebrow, its centre being over the notch. If the notch is not 
readily felt on the edge of the bony orbit at the junction of the inner and middle 
thirds, it can be detected by feeling with the tip of the finger on the orbital surface. 
The incision is made through the fibres of the orbicularis palpebrarum, corrugator 
supercilii, and frontalis muscles, then through the palpebral ligament immediately 
below the bony edge of the orbit, and the orbital fat separated with forceps; the 
nerve is then caught with a hook before it enters the notch, and brought up 
and removed. Considerable ecchymosis may follow this operation if the accom- 

Branches of the supra-orbital nerve 




Fig. 55. — Supra-orbital nerve and artery. 

panying artery is divided. Operations on the ophthalmic division of the fifth nerve 
have usually been done in connection with removal of the Gasserian ganglion, the 
other branches being also involved. 

Nasion. — About a centimetre below the glabella, in the adult skull, is the 
nasion, or line of junction of the frontal and nasal bones. It is along this frontonasal 
suture, to one side of the median line, that an anterior meningocele is apt to show 
itself. 

The internal angular process of the frontal bone articulates with the nasal 
process of the superior maxilla and the lachrymal bones. The line of suture is 
continuous with the nasion in front and the upper edge of the ethmoid behind. 
Pus originating in the ethmoidal cells, frontal sinuses, and lachrymal apparatus is apt 
to point at this locality. The frontal bone is a favorite seat of exostoses. 



THE TEMPORAL REGION. 

The region of the temple is on the side of the head as far forward as the eye 
and as low as the zygoma and infratemporal crest. The floor of the temporal fossa 
is formed by the posterior portion of the frontal and anterior portion of the parietal 
bones as high as the temporal ridge, the outer surface of the greater wing of the 
sphenoid, and the squamous portion of the temporal bone. These four bones meet 
to form the region of the pterion (see p. 39 and 42). The anterior edge of the 
temporal bone overlaps and is superficial to the posterior edge of the sphenoid. The 



THE FACE. 



47 



an 



erior edge of the parietal overlies the posterior edge of the frontal. The upper 
edges of the temporal and sphenoid overlap the lower edges of the frontal and 
parietal bones. That the temporal region of the skull is distinctly weaker than other 
regions is due to the thinness of the bones, and the reason that fractures here are 
exceptionally dangerous is on account of the middle meningeal artery running 
through a canal in the bone in this region; so that in cases of fracture the artery 
is torn and hemorrhage occurs above the dura, which causes compression of the 
brain (Fig. 56). 

The infratemporal crest (crista infratemporalis) or pterygoid ridge sep- 
arates the temporal region above from the pterygoid region below. It is an important 
landmark in operating on the Gasserian ganglion. 

A spot two centimetres behind the external angular process and slightly above 
its level marks the anterior extremity of the fissure of Sylvius. In trephining in the 



Frontal 



Glabella 



External angular 
process 




Parietal 



Anterior branch, mid- 
dle meningeal artery 



Posterior branch 
Infratemporal crest 

Middle meningeal 
artery (running up 
on the inside of the 
skull) 

Zygoma 



Sphenoid 

Fig. 56. — Frontal and temporal regions of an adult skull. 



temporal region no diploe is found in the bones, so that extreme care is necessary 
to avoid wounding the dura mater. The trephine may be placed 4 cm. ( i ^ in. ) 
behind the external angular process and 4.5 cm. (i^ in.) above the zygoma to strike 
the middle meningeal artery. This will be level with or a little above the highest 
part of the edge of the orbit. 

Temporal Fascia. — This is the dense fascia covering the temporal muscle; it 
is formed as follows: The pericranium as it comes down from the vault of the skull 
and reaches the temporal ridge passes under and gives attachment to the temporal 
muscle. The temporal fascia consists of two distinct sheets of fascia, the superficial 
one from the superior temporal ridge being attached to the zygoma below and to the 
malar bone in front; the deeper layer from the inferior temporal ridge covers the 
temporal muscle, and a short distance above the zygoma divides into two layers, 
one of which is attached to the outer edge, and the other to its inner edge. The 
upper or superficial layer of the temporal fascia leaves the bone at the superior tem- 
poral ridge and is attached below to the top of the zygoma, blending near the bone 
with the layer beneath. This is a distinct layer though not always readily demon- 
strable in dissections. Between the layers above the zygoma is some fat and the 
orbital branch of the middle temporal artery. Anteriorly the temporal fascia is. 
attached to the posterior border of the malar bone and the temporal ridge of the 
frontal. The temporal fascia is tough and dense and gives attachment by its under 



48 



APPLIED ANATOMY. 



Galea aponeurotica 



Pericranium 



Sujjerficial 



Temporal fascia 
superficial laye 

Deep laye: 



Temporal muscle 



Superior auricular 
muscle 



surface to the temporal muscle. Abscess occurring under the temporal fascia, there- 
fore, does not tend to come to the surface, but sinks downward. It is prevented 
from making its exit on the face below the zygoma by the parotid gland and 
masseter muscle, so it passes inward to the pterygoid region and may point in the 
throat or go down into the neck. 

The occipitofrontal aponeurosis, or galea aponeurotica as it approaches the 
side of the head becomes thinner and passes down to insert into the top of the 

zygoma so that in the temporal 
region the layers are as follows : 
Skin, superficial fascia, galea 
ap07ieurotica, two layers of 
the temporal fascia, temporal 
muscle, an indistinct perios- 
teum, and bone. Immediately 
above the zygoma we have the 
deep layer of the temporal fascia 
dividing instead of a single 
layer as is the case higher up. 
The temporal fossa contains 
considerable fat which dis- 
appears in serious illnesses. 
Disfiguring depressions are also 
left in this region after opera- 
tions involving the temporal 
muscle. 

The temporal artery be- 
gins opposite the neck of the 
lower jaw, then passes over the 
temporomaxillary articulation, 
lying on its capsule, thence over 
the zygoma about a centimetre 
in front of the ear. It lies on 
the temporal fascia and about 
4 cm. above the zygoma divides 
into an anterior and posterior 
branch. The course of the 
temporal artery and its anterior 
branch is usually quite conspic- 
uous in old people and affords 
a ready means of ascertaining 
whether or not the arteries 
possess the calcareous deposits 
characteristic of atheroma. The 
location of the artery in front 
of the ear should be remem- 
bered, as the pulse is readily 
felt there in the administra- 
tion of anaesthetics. In certain 
angiomas of the scalp the 
blood supply may be dimin- 
ished by ligating the vessel at 
that point. 
The temporal muscle receives blood from the middle temporal artery which comes 
from the temporal and perforates the temporal fascia just above the zygoma, and from 
the anterior and posterior temporal branches of the internal maxillary. The tem- 
poral fossa is frequently the seat of operations to expose the Gasserian ganglion and 
the bleeding from these various temporal arteries contributes to their gravity. The 
auriculotemporal nerve lies slighdy posterior to the artery and the vein in front of it. 
They are not important. 



Division of deep layer 
of temporal fascia 



Orbital branch of 
temporal artery 



Zygoma 




Pig. 57.— Transverse coronal section in the region of the temple, show- 
ing the various layers. 



THE FACE. 



49 



THE REGION OF THE CHEEK. 

In this region we may include the parts limited above by the zygoma, in front 
by the eye, nose, and mouth, below by the lower edge of the lower jaw, and behind 
by the ear. The soft parts of the cheek are supported by the malar and superior 
and inferior maxillary bones. Between the skin and the buccinator muscle, the 
hollow beneath and in front of the malar bone and masseter muscle is filled with fat, 
sometiines called the sucking pad or cushion. In disease this fat disappears, hence 
the hollow cheek of invalids. The muscles of expression are superficial to this fat 
and have their insertion in the skin. Swelling occurs readily from contusions and 
inflammations because the tissues of the cheek are lax. Inflammations may either 
start in the skin, which is quite prone to disease, or may be the result of inflammation 
of some surrounding structure, as the parotid gland, the roots of the teeth, the 
lachrymal sac, eyelids, etc. 

The skin of the cheek contains numerous sebaceous and sweat glands. It is a 
favorite site for the pustular eruptions of infancy and childhood, the acne of youth. 



Opluhalmic vein 



Ang-ular artery 
Lateral nasal 



Superior coronary 



Inferior coronary 
Inferior labial 




Nasal branch of ophthalmic 

Frontal branch of ophthalmic 



Facial artery 



Facial vein 
Fig. 58. — -The facial artery and its branches. 



and the non-malignant as well as the cancerous ulcers of the aged. It is also the 
seat of noma or cancriim oris. This starts on the mouth surface as a gangrenous 
stomatitis and implicates the cheek, causing death or great disfigurement owing 
to the loss of cheek substance. Facial carbuncle or malignant pustule occurs on the 
cheek, or sometimes on the lips. It is very often fatal. 

Wounds and contusions of the cheeks are common, and, as the blood supply is 
abundant, bleeding is free and healing prompt. On account of the insertion of 
the muscles into the skin, gaping is quite marked. 

The malar bone is the most prominent bone of the cheek. It is such a 
strong bone and so strongly supported that fracture of it, as well as that of the 
zygoma, is rare. It may be broken by direct violence, as being hit with a stone, etc. 
It is extremely difificult and often impossible to restore the fractured parts to their 
original level, therefore deformity following fracture is of frequent occurrence. 
The fracture may involve the margin of the orbit and cause an effusion of blood 
into the orbit, pushing the eye- forward. A fracture of the zvgoma, if very much 
depressed, may interfere with the use of the temporal muscle below, necessitating 
operation. This occurrence is, however, rare. 



50 



APPLIED ANATOMY. 



The facial artery runs upward and inward, from a couple of centimetres in front 
of the angle of the jaw, along the anterior border of the masseter muscle to the angle 
of the mouth, and thence to the inner canthus of the eye. The anterior edge of the 
masseter muscle can usually be distinctly felt beneath the skin. At this point the 
vessel can be ligated or temporarily compressed by passing a pin beneath it and 
winding a silk ligature above it, around the ends of the pin. This procedure is 
desirable in some operations on the cheek, as angiomas frequently affect this region. 
If the facial artery is ligated, the blood supply comes from the superior and inferior 
coronary arteries of the opposite side; the nasal branch of the ophthalmic, anasto- 
mosing with the angular; the transverse facial below the zygoma, from the temporal; 
the infra-orbital, a branch of the internal maxillary ; and to a slight extent from the 
inferior labial and others still less important (Fig. 58). 

The internal maxillary artery, one of the terminal branches of the external 
carotid, arises in the parotid gland opposite the neck of the lower jaw. This is just 
below and behind the articulation, which can be readily felt through the skin. It 

Muscular branches 
/ 



Infra-orbital 

\ Superior alveolar 
(posteriordental) 



External ptery- 
goid muscle 
Internal ptery- 
goid muscle 



Superficial temporal 

artery 

Sphenomandibular 

ligament' 

Middle meningeal- 



External carotid--' 
Inferior alveolar (dental) 




Buccal nerve 



Lingual nerve 



Inferior alveolar 
iiL-rve 



F:g. 59. — 'I'he internal maxillary artery. 

passes between the bone and the sphenomandibular (long internal lateral) ligament, 
then between the two pterygoid muscles or between the two heads of the external 
pterygoid muscle to the posterior surface of the superior maxillary bone in the 
sphenomaxillary fossa. The branches of its first part, where it is behind the neck of 
the jaw, are the deep auricular, tympanic, ')niddle and small meniitgeal, and inferior 
alveolar {dental). The branches of its second part, as it passes between the ptery- 
goid muscles, are all muscular : they are the masseteric, pterygoid, anterior and 
posterior deep temporal, and the buccal. The branches of the third portion of the 
artery, in the sphenomaxillary fossa, are the posterior dental, infra-orbital , descending 
palatine. Vidian, pterygopalatine , and sphoio- or nasopalatine. 

The main trunk of the internal maxillary artery is not often involved either by 
injury or operations. The various branches are, however, of considerable impor- 
tance, as they supply parts which are often the site of operative measures. The 
importance of the middle meningeal artery in reference to fractures of the skull has 
already been pointed out. The inferior alveolar gives rise to troublesome hemorrhage 
when the lower jaw is operated on. The deep temporal branches bleed freely when 
the temporal muscle is incised in operating on the Gasserian ganglion. The infra- 
orbital is involved in operating on the infra-orbital nerve. The posterior or descending 
palatine branch descends in the posterior palatine canal, in company with a branch 




THE FACE. 



51 



I 



from Meckel's ganglion, to emerge on the roof of the mouth at the posterior palatine 
foramen. It causes free hemorrhage in operating on cleft palate. 

The \'idian and pterygopalatine branches supply mostly the roof of the pharynx; 
they bleed when adenoids are removed. The descending and sphenopalatine sup- 
ply the upper part of the tonsil with blood and may give rise to serious hemorrhage 
in the removal of the tonsils. In operating on Meckel's ganglion, bleeding from 
these vessels is free. The nasopalatine runs forward in the nose in the groove on 
the vomer. It is often the cause of serious nasal hemorrhages in operations on the 
septum. In removal of the upper jaw, bleeding occurs from many of the branches 
of the internal maxillary, but it is hardly so free as might be expected, especially if 
the external carotid has been previously ligated. 

PAROTID GLAND. 

The parotid gland lies on the cheek, behind the jaw and below the ear. The 
limits (Fig. 60) of the gland are important because suppuration may occur in any por- 
tion of its structure. Its extent is as follows : above to the zygoma, lying below its 



Superficial temporal artery 
Transverse facial artery 
Parotid duct 



Facial nerve 



Parotid gland 




Auricularis 
magiius nerve 



Submaxillary gland 

Facial artery and vein 
Fig. 60. — Parotid gland and structures of the side of the face. 

posterior two-thirds; posteriorly, to the external auditory canal, the mastoid process, 
and digastric and sternomastoid muscles ; below to a line joining the angle of the jaw 
and mastoid process ; and in front about half the width of the masseter muscle. 
This latter is, however, quite variable. 

The parotid duct, also called Stenson' s duct, leaves the upper anterior portion 
of the gland about a centimetre below the zygoma and runs on a line joining the 
lower edge of the cartilaginous portion of the ear with the middle of the upper lip. 
It opens on a papilla on the inside of the cheek opposite the second upper molar 
tooth. This papilla can readily be seen and a fine probe can be inserted from the 
mouth into the duct; thus the presence of a calculus may be detected. In operating 
on the cheek the line of this duct must be borne in mind, as wounding it may cause 
a salivary fistula. Wounds of the lobules of the gland are not nearly so liable to 
result in fistula as those of the duct itself. 



52 APPLIED ANATOMY. 

Parotid Fascia. — The gland is covered by the parotid fascia. This fascia is 
moderately dense and is continuous with the fascia separating the lobules of the gland. 
Above it is attached to the zygoma ; in front it is continuous with the masseteric 
fascia over the masseter muscle ; and below and posteriorly it is continuous with the 
deep fascia of the neck. It stretches from the angle of the jaw to the sternomastoid 
muscle and somewhat deeper to the styloid process ; the band running from the 
styloid process to the lower jaw is called the stylomandibular ligament. From 
thence it is continued over the internal carotid artery and the upper surface of the 
internal pterygoid muscle. 

Lobes of the Parotid Gland. — The gland has extentions in various directions 
(Fig. 6i). A prolongation behind the articulation of the lower jaw, into the posterior 
portion of the glenoid cavity immediately in front of the external auditory canal, is 
called the gleyioid lobe. Another extension winds around the posterior edge of the 
lower jaw on the lower surface of the internal pterygoid muscle and is called ih^ ptery- 

Glenoid 
lobe 

/ 

■Socia parotid is 




Pterygoid lobe 
Digastric muscle \ \ 

Carotid lobe External carotid artery 
Fig. 6i — The lobes of the parotid gland. 

goid lobe. A prolongation inward, passing between the external carotid on the outside 
and the styloid process and the internal carotid artery on the inside, is called the 
carotid lobe. A separate portion of the gland, sometimes quite detached, lies at its 
upper anterior portion between the zygoma and the duct of Stenson; it is called the 
socia parotidis. 

Vessels and Nerves Traversing the Gland. — The external carotid artery 
enters the gland to divide opposite the neck of the lower jaw into the temporal and 
internal maxillary. The temporal, before it leaves the gland, gives off the trans- 
verse facial artery which runs forward on the face between the zygoma and parotid 
duct. It is usually small but at times may be quite large and even go over to the 
angle of the mouth and form the two coronary arteries (as shown in M'Clellan's 
"Regional Anatomy"). The temporal vein, as it descends into the gland, is joined 
by the internal maxillary vein to form the temporomaxillary vein, which, after it 
receives the posterior auricular vein, goes to form the external jugular. 

The facial nerve emerges from behind the jaw just below the lobe of the ear and 
divides into its various branches while still in the gland. There is usually a large 
branch passing parallel to the duct of Stenson and IdcIow it. The auriculotemporal 
nerve follows the temporal artery, emerging from the gland a little posterior to the 
artery. Dr. Skillern has shown that, by injecting it with cocaine, operations on the 
walls of the meatus externus for furuncles, etc. , can be rendered painless. The auric- 
ularis magnus from the second and third cervical supplies the skin over the gland. 



1 



THE FACE. 



53 



Lymphatic nodes are found both on the gland and in its substance. These may 
be involved in general disease of the cervical lymphatics. 

Affections of the Parotid Gland. — The duct may be affected with calculus, 
as already mentioned. As the opening of the duct at the papilla is smaller than the 
lumen of the canal farther back, calculi are apt to lodge close to the anterior extrem- 
ity. They are, therefore, readily felt and removed by incision on the inside of the 
mouth. The gland proper is subject to inflammations and tumors. 

Simple parotiditis or viiunps really is an infectious inflammation, nevertheless, it 
rarely suppurates. Siippiirative parotiditis may occur from infected wounds or arise 
in the course of the eruptive fevers, etc. In inflammation of the gland, pain and 
swelling are important symptoms. The pain, which is considerable, is not due so 
much to the so-called dense parotid fascia covering the gland, for this is only 
moderately thick, as it is to the fact that the gland is of a racemose type and the 



Branches of 
facial nerve 



Temporal artery 

Parotid duct 




Auricularis 
niagiius nerve 



'Jugular vein 

External carotid 
artery 



Fig. 62.— Structures in relation with the parotid gland. 

fibrous septa between the lobules are abundant and prevent free expansion of the 
contained lobules. Expansion is also hindered by the peculiar location of the various 
parts of the gland. SweUing of the glenoid lobe produces pain in the ear and also in 
the temporomaxillary articulation. Swelling of the carotid and pterygoid lobes 
causes pain and fulness in the throat. Opening the lower jaw reduces the space 
posterior to it in which the gland lies and pinches it against the bony meatus and 
mastoid process, so that it is impossible to open the jaw widely. 

If suppuration occurs it is liable to progress from one lobule to another; when 
this is the case comparatively small abscesses may appear in different parts of the 
gland with unaffected tissue between them. As an abscess heals in one lobule, sup- 
puration is apt to occur in another, consequently the disease may persist for a long 
time. More rarely in the course of or following infectious diseases, particularly in 
debilitated patients, considerable portions of the gland may slough. This form is apt 
to be fatal. If the suppurating focus is confined to lobules which are deeply placed, 
the diagnosis may be obscure because it is difficult to localize the affected spot. If, 
however, it is near the surface of the gland, the pus does not tend to extend sideways, 
the fibrous septa prevent this, but it tends to work its way up and perforate the skin. 
If the glenoid lobe is affected, the pus may find an exit through the external auditory 
meatus or even involve the temporomaxillary joint. If the carotid or pterygoid lobes 



54 



APPLIED ANATOMY. 



are affected, the pus may go between the pterygoid muscles, or around the 
internal carotid artery and project and open into the pharynx. It may also break 
into the carotid artery or jugular vein, or perforate through the fascia below and 
go down the neck. Large abscesses and sloughs may be followed by a parotid 
fistula. 

Lines of Incision for Abscess. — The manner of opening a parotid abscess 
depends on its location and size. If it is desired to open an abscess anterior 
to a point 1.5 cm. or about half an inch in front of the ear, the structures to be 
avoided are the duct and facial nerve. The incisions are to be made parallel 
to the zygoma, and the duct is to be avoided by not cutting on a line joining 
the lower edge of the cartilage of the ear with the middle of the upper lip. The 
branches of the facial nerve lie deep and are to be avoided by making the 
incision parallel to their course and not extending it too deeply. After incising 

the skin, the deeper tissues may be sepa- 
rated by introducing a pointed pair of haemo- 
static forceps and opening the blades. In 
operating in the region below the ear, the 
blood-vessels are to be avoided. To do 
this incise the skin longitudinally, not trans- 
versely, and open the deep parts carefully 
with the haemostatic forceps, as already 
described. Another method, when the ab- 
scess is farther forward, is to make a hori- 
zontal incision rather low down on the 
angle of the jaw and then introduce a 
grooved director or haemostatic forceps from 
below upward. 

Tumors of the parotid gland are liable 
to be mixed in character, with a sarcoma- 
tous element. They are often fairly cir- 
cumscribed and, particularly if they do 
not involve the parotid duct, can be re- 
moved comparatively readily. If they are 
malignant and large, complete removal is 
practically impossible. The possibility of 
parotid fistula and paralysis of the facial 
nerve following operation on this gland should always be borne in mind and explained 
to patients. The presence of facial paralysis is indicative of malignancy (see Fig. 63). 
'I'he parotid lymph nodes on or beneath the capsule may become enlarged and 
inflamed and resemble true parotiditis. There is one node just below the zygoma 
and in front of the ear that is not infrequently enlarged in strumous children. This 
is apt to be involved when affections of the lids or scalp are present. In open- 
ing abscesses of these nodes there is little likelihood of injuring either the nerve or 
the duct, because the nodes are superficial. The transverse facial artery is usually 
too small to cause trouble. The possibility of its supplying the coronary arteries 
of the lips, as already described, in which case it would be very large, should be 
remembered. 

THE UPPER JAW. 

The upper jaw carries the upper teeth and contains the maxillary sinus or 
antrum of Highmore. The afiections of the antrum will be alluded to in the chapter 
on the nose (see page 103). Fractures of the superior maxilla involve the nasal 
process, the alveolar process, or pass transversely through the body of the bone. 
The nasal process is sometimes broken in fractures of the nose. In this injury, the 
lachrymal canal and sac may be injured and the flow of tears through them pre- 
vented, causing the tears to run over the cheek. 

Fractures of the alveolar process are common enough as a result of blows and 
extracting teeth. These fractures, as they communicate with the mouth through the 
broken gums or mucous membrane or tooth socket, are necessarily compound, and 




Fig. 63. — Malignant tumor of the parotid gland 
producing facial paralysis (author's case). 



THE FACE. 



55 



consequently become infected from the mouth and suppurate. This may cause 
necrosis of the fragment, but the blood supply of the jaws is so good that death of 
a fragment is rare, and it is not customary to remove fragments not completely 
detached. The front wall is sometimes driven in. 

Fractures occasionally occur in which the line passes through one or both 
superior maxillary bones from below the malar bone into the nose. If this fracture 
passes completely backward, it detaches the lower portion of the palate bone and 
pterygoid processes of the sphenoid bone. The fragment in such cases has a 
tendency to slip backward. It can be replaced by inserting a hook through the 
mouth and behind the soft palate and pulling the fragment forward. This 
injury is produced by a blow on the anterior portion of one or both bones, 
passing downward and backward. In order to determine the existence of fract- 
ure, Guerin recommended inserting the finger in the mouth and feeling for the 
pterygoid plates. The hamular process of 
the internal pterygoid plate can readily 
be felt about one centimetre above and 
behind the last upper molar tooth. Fract- 
ures in the neighborhood of the first and 
second molar teeth are liable to open the 
antrum, as the roots of these teeth project 
into it. 

Resection of Upper Jaw. — Tumors 
of the antrum may necessitate a resection 
of the superior maxilla of one side. Hey- 
felder was the first to remove both superior 
maxillae, in 1844: this was before the dis- 
covery of anaesthesia. In removing one 
superior maxilla, the incision known as Fer- 
giisson's is used. This is made through 
the middle of the upper lip, around the ala 
of the nose to the inner canthus of the eye, 
thence outward along the lower border .of 
the orbit to the malar bone. The bleeding 
from this incision is free. The coronary 
arteries should be looked for near the 
mucous surface of the lip toward its free 

edge. Bleeding will also occur from the lateralis nasi and the angular arteries. 
The soft parts are raised from the bones as far back as the masseter muscle. 
This is just about level with the outer edge of the bony orbit. In doing 
so the infra-orbital nerve and artery will be divided. The artery is not large 
but may bleed freely. The fibrous floor of the orbit is raised and the attach- 
ment of the inferior oblique muscle loosened. The malar bone is sawed downward 
and outward opposite the sphenomaxillary fissure, and the division completed with 
forceps. The nasal portion of the superior maxilla is sawed through from the orbit 
into the nose. The soft parts of the roof of the mouth are divided in the median 
line to the posterior edge of the hard palate, and thence along its edge to the last 
molar tooth. The soft palate is firmly attached to the hard palate and has to be 
detached with scissors. An incisor tooth is then drawn, and the bony palate sawed 
through from the nose into the mouth. The bone with the tumor is wrenched loose 
with lion-jawed forceps. The union between the posterior portion of the superior 
maxilla and the pterygoid processes of the sphenoid is not bony, but fibrous, so that 
the bone is torn away from the processes and the latter are left behind. As the bone 
comes away, the maxillary nerve should be cut. The bleeding which follows is from 
the infra-orbital, superior alveolar (posterior dental), and posterior palatine arteries, 
branches of the internal maxillary. It is not so free as might be expected, provided 
preliminary ligation of the external carotid has been performed. It will be observed 
that the facial nerve is not touched nor is the parotid duct wounded. 

Neuralgia of the Maxillary Nerve. — The pain involves the cheek from the 
eye to the mouth and as far forward as the median line, also the upper gums and 




Fig. 64. — Resection of the upper jaw. The 
curved lines indicate the skin incision and the 
straight Hnes where the bones are to be divided. 



56 APPLIED ANATOMY. 

hard palate. The operations devised for its I'elief are both numerous and intricate, 
and necessitate an accurate anatomical knowledge of the ])arts. The maxillary 
nerve is the second division of the fifth cranial nerve. It leaves the skull cavity by 
the foramen rotundum, then crosses the sphenomaxillary fossa, enters the spheno- 
maxillary fissure and infra-orbital canal to emerge on the cheek, opposite the middle 
of the lower edge of the orbit and about 6 mm. below it. The intracranial portion 
is 6 to 8 mm. in length. From the sphenomaxillary fossa to the infra-orbital fora- 
men is about 5 cm. (2 in. ). Its branches are as follows: one or two small branches 
to the dura mater, the orbital or sphenomalar branch to the cheek and anterior tem- 
poral region, spheyiopalatine bra7iches going to Meckel's ganglion, the posterior, 
middle, and anterior dental to the upper teeth, and the terminal branches, labial, 
nasal, and palpebral, on the face. 

Its anterior portion has been removed through an incision on the face, and its 
posterior portion with Meckel's ganglion has been operated on either anteriorly 
through the maxillary sinus or laterally through the temporal fossa, after removing 
the zygoma. The writer has removed the intracranial portion by entering the ante- 
rior cerebral fossa through the temporal region. Removal of the infra-orbital portion 




^ ..^J^^^i^ ^''"■'•Br^v ^^^""^ Infra-orbital nerve 

breaking into branches 



Infra-orbital artery 



Fig. 65. — Exposure of the infra-orbital nerve and artery. 

of the nerve is so liable to be followed by recurrence of the pain and interferes so 
much with the more complete procedures, as it destroys the guide (the nerve itself) 
which leads the operator to Meckel's ganglion, that it is doubtful whether it should 
ever be resorted to. The posterior dental branches are given off so far back that 
they are not apt to be removed in this operation. 

Removal of the Infra-orbital Nerve. — An incision 3 cm. in length is made 
along the lower edge of the orbit. This divides the orbicularis palpebrarum muscle. 
Arising from the bone, between the infra-orbital foramen and the edge of the orbit, 
is the levator labii superioris muscle. This should be carefully detached, and the 
foramen with its artery and nerve will be found opposite, the middle of the lower edge 
of the orbit and about 6 mm. {y^ in. ) below it, on a line drawn from the supra-orbital 
notch to between the premolar teeth. The position of the foramen having been 
located, the palpebral ligament and periosteum are divided and the contents of the 
orbit raised. The canal is next to be opened. This can be done either by chiselling 
away its roof from the opening on the face and following it backward or by breaking 



THE FACE. 



57 



through its upper wall. This latter procedure is liable to give trouble, because if 
the track of the canal is not encountered the instrument breaks into the maxillary- 
sinus, the roof of which is very thin. The infra-orbital canal does not pass directly 
backward but backward and outward, striking the sphenomaxillary fissure about 2 
cm. (in a large skull) behind its anterior extremity. Sometimes the roof of the 
canal is fibrous, in which case the groove so formed can be readily felt, but in others 
it is bony. The nerve is hooked up and cut as far back as one can, so as to remove, 
if possible, the posterior dental branches. The terminal branches are then pulled off 
from the cheek, and the nerve drawn out from the front. It is in the highest degree 
desirable to avoid wounding the artery, as death is said to have followed it, and 



4th nerve 



Ophthalmic branch — 5lh nerve 
Motor root 

Sensory root 

Maxillary branch 

Gasserian ganglion 



Meckel's ganglion 



Infra-orbital 
nerve and artery 




Middle meningeal artery 
Mandibular branch 
Temporomalar n^rve 



Buccal branch 

Stump of external 
pterygoid muscle 

Lingual nerve 

Inferior alveolar 
nerve and artery 



_ Internal pterygoid 
muscle 



Fig. 66.— The fifth or trifacial nerve with its various branches. 



there may be bleeding into the orbit, causing protrusion of the eye and serious inter- 
ference with its sight. A better way of removing the nerve, the method of Thiersch 
( Verhand. der Deidschen Gesell. fiir Chir., 18 Congress, Berlin, 1889, p. 44), is to 
grasp it with a pair of slender, curved forceps, then by rotating the forceps very 
slowly (about i turn a minute) both the distal and proximal ends are wound around 
it and an extremely long portion of the nerve can be removed. 

Removal of Meckel's Ganglion, — Operating from the froyit through 
the maxillary sinus (Carnochan's operation, or removal of the sphenopalatine 
(Meckel's) ganglion and maxillary nerve). — The incision is V-shaped, the apex 
being 2 cm. above the angle of the mouth, and the branches 3 cm. long. This flap 
should consist of all tissues down to the bone. The bleeding will be free, as the 
facial vein and branches of the facial artery will be cut. As the infra-orbital foramen 
is reached, the nerve is detached from its under surface. The anterior wall of the 



58 APPLIED ANATOMY. 

maxillary sinus, which is quite thin, is broken with a chisel for an extent of 2 cm. 
The infra-orbital canal is opened from below, from the surface clear back to the pos- 
terior wall of the sinus. The infra-orbital nerve is then brought down into the sinus 
to serve as a guide to the foramen rotundum. Care should be taken (by opening 
the canal with comparatively blunt instruments) not to wound the infra-orbital artery. 
Then break a hole in the posterior wall of the sinus. This is very thin, and not over 
half a centimetre (i in. ) intervenes between it and the anterior wall of the sphenoidal 
sinus, so that care should be taken not to drive the chisel too far back. The pos- 
terior wall having been broken with the chisel and the pieces picked away, the nerve 
is dragged downward, freed as far back as possible, and pulled loose. Traction on 
the nerve brings the ganglion forward, and with forceps it is then drawn out. The 
bleeding, after breaking through the posterior wall of the sinus, may be very free. 
Meckel's ganglion lies in the sphenopalatine fossa just below the maxillary nerve 
after it leaves the foramen rotundum. Two short branches unite the ganglion and 
nerve. It is here that the internal maxillary artery, in the third part of its course, 
divides into six branches: the infra-orbital and posterior de?ital, the posterior or 
descending- palatitie and Vidian, and the pterygopalatine and spheno- or nasopalatine 
arteries. If these arteries are wounded, as they are very apt to be, the bleeding is 
very free. To control it temporary packing is at first resorted to. If it persists, the 
nerve is removed as well as possible and the bleeding stopped with gauze. This 
may be firmly packed into the opening through the posterior wall at the upper inner 
portion of the sinus, but care should be taken not to push it roughly through the 
fossa and into the sphenoidal sinus (or cells) beyond. 

J. D. Bryant {^Operative Surgery, vol. i, p. 243) in cases of severe hemorrhage 
advises the prompt ligation of the external carotid artery, a procedure not, however, 
often required. It has been suggested that instead of making the incision on the 
cheek to make it in the mouth above the gums, and pull the cheek and mouth 
upward and outward. This procedure, while obviating the scar, makes the opera- 
tion somewhat more difficult. Kocher resects the malar bone with the outer wall of 
the sinus and turns it up, bringing it back into place on the completion of the 
operation. 

Operating from the Side Through the Pterygoid Fossa. — Both the 
maxillary and mandibular branches have been reached by this route; the former at 
the foramen rotundum and the latter at the foramen ovale. Liicke, of Strasburg, 
was the pioneer of the operation on the maxillary nerve, and Joseph Pancoast, of 
Philadelphia, on the mandibular. Liicke' s operation was modified by Lossen, of 
Heidelberg. Recently, Mixter, of Boston, has again advocated the method. A 
convex flap, base down and reaching y^ inch below the zygoma, is cut from the 
external margin of the orbit to the lobe of the ear. The zygoma is sawed through, 
and, with the masseter, pulled downward. Maurice Richardson, in describing Mix- 
ter' s operation { Internal. Textbook of Surg., vol. i, p. 863), says that "if the 
operator is skilled enough in the subsequent manipulations, he may omit cutting the 
temporal muscle." It will be easier, however, to divide the coronoid process and 
turn the temporal muscle upward, clearly exposing the infratemporal crest. Detach 
the upper head of the external pterygoid muscle and push it downward, exposing 
the external pterygoid plate. Chisel ofT the spur at the anterior extremity of 
the infratemporal crest, and immediately in front and to the inner side is the supe- 
rior maxillary nerve, with the terminal portion of the internal maxillary artery 
just below it. Immediately posterior to the root of the pterygoid plate is the 
foramen ovale and mandibular nerve, with the middle meningeal artery a little 
posterior to it. 

Anatomical Comments. — The incision at its posterior extremity can be 
made to avoid cutting the temporal artery by feeling its pulsations, about a centimetre 
or less in front of the ear, as it passes over the zygoma. The incision should not 
involve the deep structures — only the skin and superficial fascia. Therefore, the 
facial nerve and parotid duct (a finger's breadth below the zygoma) will not be 
injured. 

In clearing the upper surface of the zygoma, it will be necessary to cut through 
the layers of the temporal fascia; between them the orbital branch of the temporal 



THE FACE. 



59 



artery may be encountered and may bleed. The temporal muscle arises not only 
from the deep layer of the temporal fascia, but may also be attached anteriorly to 
the inner surface of the zygoma, and in loosening it free bleeding from the deep 
temporal arteries, branches of the internal maxillary, may be encountered. No 
trouble need be expected in sawing through the anterior end of the zygoma, but care 
should be taken not to injure the parotid duct, or the socia parotidis if it is present. 
In making the division of the posterior end of the zygoma, one must guard against 
opening the temporomaxillary articulation, for, when the head of the mandible is 
back in the glenoid fossa, the capsule of the joint extends considerably in front of it. 
Therefore, it is better to open the mouth and push the jaw on that side forward until 
it rides on the eminentia articularis, then the anterior limit of the joint can be recog- 
nized and avoided. Before one can reach the spur on the anterior extremity of the 
infratemporal crest, " the temporal muscle must be detached from the bone. The 



Processus coronoideus 




Temporalis 



Crista infratempo- 
ral is 



Spur 



N. maxillaris 



A. infra-orbitalis 
A. temporalis 
profundus 
A. alveolaris 
posterior 
A. maxillaris 
internus 



N. mandibularis 

M. pterygoideus ex- 

ternus. Upper head 

turned down 

Masseter 



Zygoma 



Fig. 67.— Operating- through the pterygoid fossa. The skin with the zygoma and masseter have been turned 
down. The coronoid process is divided and turned up. The upper head of the external pterygoid has been 
detached and turned down. The maxillary nerve is in front of the pterygoid plate (processus pterygoideus) and 
the mandibular nerve and middle meningeal artery just behind it. 

upper head of the external pterygoid muscle arises from the bone just below the 
pterygoid ridge (infratemporal crest), and must be loosened from the bone to obtain 
access to the nerves (see Fig. 67). 

The coronoid process rises almost as high as the infratemporal crest, and, there- 
fore, in order to gain space it will be necessary to depress the jaw. Running upward 
and inward over the internal pterygoid muscle, and passing just in front of the origin 
of the upper head of the external, is the internal maxillary artery and pterygoid 
plexus of veins. These vessels lie directly below the maxillary nerve as it crosses 
the sphenopalatine fossa, and it is to be expected that free hemorrhage will accom- 
pany the attempt to fish out the nerve. 

In operating in this region, one surgeon found the bleeding so severe as to 
require the ligation of the external carotid artery. 

Intracranial operations are hardly ever done for maxillary neuralgia alone. The 
mandibular and often the ophthalmic divisions are also usually affected in cases 
requiring to be approached from the inside of the skull. 



6o 



APPLIED ANATOMY. 



Excision of the Lingual and Inferior Dental Nerves. — Neuralgia in- 
volving' the face below the line of the mouth, the lower teeth, and side of the tongue 
requires the removal of the inferior dental and lingual nerves. To do this, a curved 
incision following the lower edge of the mandible is made. It ends anteriorly in 
front of the mandibular foramen, and posteriorly it stops a centimetre below the ear to 
avoid wounding the facial nerve. The masseter muscle is raised from the bone, and, 
with the parotid gland, is drawn up. The ramus of the jaw is trephined in its middle, 
rather high up toward the coronoid notch. The outer table of bone is then to be 
chiselled off, from the trephine opening as far down as the mental foramen. A 
delicate, curved, haemostatic forceps is then made to grasp both nerves through the 



Lingual nerve 

Internal pterygoid muscle 

Mandibular nerve 




Fig. 6S. — Excision of the lingual and mandibular (inferior dental) nerves. 

trephine opening, and on rotating very slowly the nerves are wound around the for- 
ceps and are gradually torn loose from the base of the skull above to their ultimate 
branches below (see Fig. 68). 

Operations on the Gasserian Ganglion. — The Gasserian ganglion lies in 
its capsule, formed by a splitting of the dura, on the anterior surface of the apex of 
the petrous portion of the temporal bone and on the root of the greater wing of the 
sphenoid. From its posterior extremity, which rests on the ridge separating the 
anterior and posterior surfaces of the petrous portion of the temporal bone, to the 
foramen rotundum anteriorly is 2. 5 to 3 cm. (i to i ^ in.). The foramen ovale, which 
transmits the third or mandibular branch is midway between these two points, and 
corresponds on the outside of the skull to the eminentia articularis or root of the 
zygoma. Therefore, in removing the ganglion one works not only inward but also 
backward. Rose first operated on the ganglion from below. He removed the 
zygoma and coronoid process, Hgated the internal maxillary artery, and trephined 
the skull in front of the foramen ovale. This operation was succeeded by that of 
Hartley and Krause. They went in through the temporal fossa. A large horseshoe- 
shaped flap, with its base above the zygoma, was cut and deepened with chisels 
through the bone to the dura. This was elevated by breaking across its base, and turn- 
ing it down. The dura was then lifted from the base of the skull, and the maxillary 
and mandibular nerves recognized as they passed into the round and oval foramina. 
The capsule having been incised, these were seized with forceps, and as much of the 
ganglion as possible torn away. 

Other surgeons, like Doyen, Quenu, Poirier, and Gushing, have combined these 
pterygoid and temporal routes. The bone flap, as made by Hartley and Krause. 



THE FACE. 



61 



embraced the region of the pterion or junction of the coronal with the temporo- 
sphenoidal sutures. As the bone was lifted from the dura at this point the middle 
meningeal artery was torn and troublesome bleeding ensued. Also the point of its 
breaking was too uncertain. Sometimes it broke too high up, sometimes too low 
down involving the base. It was also found unnecessary to replace the bone as 
the cavity left was filled up with fibrous tissue. For this reason Tiffany, of Baltimore, 
advocated the making of an opening in the skull above the zygoma with a trephine 
or gouge and mallet, and enlarging it with the rongeur forceps; the bone was not 
replaced. This is the procedure now used. 

The operators who used the pterygoid route, by displacing the zygoma down- 
ward, were enabled to approach the ganglion from below instead of from above, 
therefore, a high temporal section of the bone was unnecessary and it has been 
abandoned; the bone section keeping below the pterion and not wounding the 



N.ophthal- 
Gansjlion semilunare micus N. niaxillaris 



A. meningea media 



N. iiiaiidibularis 



M. pterygoideiis 
extenius, upper head 

M. pterygoideus 
externus, lower head 



M. pterygoideus interims 

N. alveolaris inferior 
(inferior dental) 

N. lingualis, 




N. buccinatorius 



Fig. 69.— The upper portion of the illustration shows the operation of removal of the Gasserian ganglion (ganglion 
semilunare). The lower portion shows the pterygoid muscles. 



middle meningeal artery thus avoids hemorrhage from that locality. Gushing 
(Journ. Am. Med. Assoc, April 28, 1900) showed that the extensive removal of bone 
on the base of the skull was unnecessary, and that a displacement of the zygoma 
and temporal muscle downward, and removal of the bone down to and including 
part of the infratemporal crest gave sufficient access. Murphy found it unnecessary 
to resect the zygoma, and this has been our experience. 

One of the main difificulties has been the question of bleeding. It has caused 
death and not infrequently has necessitated the packing of the wound and the 
deferring of the completion of the operation for two or more days. This bleeding 
came from the soft parts, the bone, the middle meningeal artery, the veins running 
from the dura mater to the bone, the cavernous sinus, and the blood-vessels to the 
ganglion itself. These as given by Gushing are a branch from the middle meningeal 
soon after its entrance to the skull, a small branch from the carotid, a small branch 
from the ophthalmic, the small meningeal through the foramen ovale, and occasion- 
ally one through the foramen rotundum. He calls attention to the septa in the 
cavernous sinus as rendering wounds to it less serious than they otherwise would be. 
If the skin incision is cast too far back, the temporal artery may be cut in front of the 
ear. Its position can be determined by its pulsation. It or its branches are divided 
in the upper portion of the incision and bleeding is very free. Division of the 
temporal muscle is followed by hemorrhage from the deep temporal. The bleeding 
from the bone is usually not troublesome, but the general oozing from the veins of 



62 



APPLIED ANATOMY. 



the dura mater as it is detached from the bone is sometimes free. If an osteoplastic 
(bone and skin) flap is raised, the middle meningeal will be torn at the pterion. 
This is a large vessel and bleeds freely. It may also be torn, while isolating the 
mandibular division of the nerve, at the foramen spinosum. This foramen is usually 
a couple of millimetres posterior and to the outer side of the foramen ovale and 
generally the nerve can be isolated without injuring the artery. In some cases, how- 
ever, the artery lies so close to the nerve that it is almost certain to be torn. The 
posterior portion of the ganglion lies on the carotid artery in the middle lacerated 
foramen, of course separated by a layer of dura mater. Care should, therefore, be 
taken not to injure the carotid artery. The cavernous sinus has often been injured. 
This occurs principally in those cases in which it is attempted to excise the 
ophthalmic division. It is to be avoided by working from behind forward instead of 
attempting to attack it laterally. Bleeding from the middle meningeal artery can be 



ophthalmic- 



Maxillary 




P-A ^I-«d'bul 



Maxillarj- _ 
Mandibular ^A 

ical plexus 




Fig. 70. — Diagrams showing distribution of cutaneous branches of trigeminal and cervical spinal nerves (Piersol). 

avoided by biting the skull away with the rongeur forceps and refraining from 
detaching the dura from the bone where the artery enters it (see Fig. 23). 

Gushing states that he makes an opening in the bone only 3 cm. in diameter. 
Such a small opening is used when the zygoma has been divided and pushed down 
or removed. Fowler and others have resorted to a preliminary Hgation of the 
external carotid artery. This, while obviating to a great extent troublesome hem- 
orrhage, cuts of? the blood supply to the flap and sloughing has followed. In 
order to overcome this objection, the writer {Jojirn. Am. Med. Assoc, April 28, 
1900) after ligating the external carotid artery above its posterior auricular branch 
made a temporal skin flap with its base up. The temporal muscle was then divided 
and turned down and the bone removed with the trephine and rongeur. Haemostasis 
was perfect and no ill effects followed the ligation. 

It is comparatively easy to isolate the maxillary and mandibular divisions of the 
nerve. This having been done, the capsule of the ganglion is opened by a cut 
joining the two. A blunt dissector is then introduced and the upper layer of the 
dura, less adherent than the lower, is raised from the ganglion. The blunt dissector 
is then worked beneath the ganglion beginning between the maxillary and mandib- 
ular divisions and it is loosened from behind forwards. The sixth nerve is in such 
close relation to the ophthalmic that a temporary paralysis of it usually follows, 
causing internal squint. Anaesthesia of the whole side of the face from just in front 
of the ear to the median line follows complete removal. Frazier and Spiller have 
divided the root posterior to the ganglion instead of removing the ganglion itself 
(^Joiirn. Am. Med. Assoc. ^ Oct. i, 1904, p. 943). 



THE FACE. 



63 



Area of Distribution of the Fifth Nerve, — When the ophthahiiic division 
is affected the pain in neuralgia is over the brow and up toward the vertex of the 
skull; it also involves the eye. The points of exit of the supra-orbital branch at 
the supra-orbital foramen and of the nasal branch toward the lower portion of the 
nose are tender to pressure. 

When the maxillary division is affected, there is pain in the cheek and ala of 
the nose. The tender points are the exit of the infra-orbital nerve at and below 
the infra-orbital foramen, at the exit of the malar branch on the malar bone, and 
tne upper gums and hard palate. 

When the mandibular division is affected the pain involves the lower jaw and 
the side of the head nearly to the top (auriculotemporal branch). The lower gums 
and tongue are also painful. Pain on pressure is felt over the mental foramen and in 
the course of the auriculotemporal nerve in front of and above the ear. 



THE LOWER JAW. 

The mmidible or mferior maxilla is subject to fractures, dislocation, and tumors. 
In its composition it is very dense, so that in dividing it a groove should be cut 
with a saw before the use of the bone-cutting forceps is attempted, otherwise 




Fig. 71. — Lower jaw of child and adult, showing the mental foramen. 

splintering of the bone will ensue. It is the last bone to decay. Its horseshoe 
shape and exposed position render it unusually liable to fracture. The strongest 
portion is what one would expect to be the weakest, viz., the symphysis. Its 
weakest part (or rather the part where it is most often broken) is the region of the 
mental foramen. The bone is weakened at this point not only by the foramen 
but also by the deep socket of the canine tooth. 

The position of the mental foramen, normally between the two bicuspids 
(beneath the second in the negro — Humphry), varies in its vertical location between 
the alveolar border and lower edge of the body, according to age. In infancy it is 
low down, in young adults it is midway, and in old people it is high up. 

The body of the jaw is composed of two parts, one above and one below the 
external oblique line, which runs from the base of the anterior border of the 
coronoid process downward and forward to end at the mental tubercle, to one side 
of the symphysis. The part above this oblique line is the alveolar and the part 
below is the basal portion of the body. 

The mental foramen opens on the oblique line separating the alveolar and basal 
portions. In early adult life the two portions, basal and alveolar, are about even in 
size, so that the foramen is below the middle of the jaw. As the teeth are lost 
the alveolar process atrophies ; this naturally leaves the basal portion with the mental 



64 



APPLIED ANATOMY. 



foramen on or near its upper surface; therefore, in operating for neuralgia in the 
aged, if it is desired to attack the mandibular nerve in its canal, it should be searched 
for near the upper border of the bone. 

In infancy the teeth, not having erupted, are contained in the jaw, the alveolar 
portion is, therefore, large. The basal portion, on the contrary, is quite small, serv- 
ing merely as a narrow shelf on which the unerupted teeth lie. As the mandibular 
nerve runs beneath the teeth, the mental foramen is of necessity comparatively low. 
At birth the condyle is about level with the upper portion of the symphysis, and the 
body forms with the ramus an angle of 175 degrees. At the end of the fourth year 
the angle has decreased to about 140 degrees. By adult age the angle has decreased 
to about 115 degrees, and as the teeth are lost the angle gradually increases until it 
again reaches 140 degrees. 

Temporomandibular Articulation. — A knowledge of the movements of the 
jaw is essential to a proper understanding of the fractures and dislocations to which 
it is subject. 



Temj)oralis 




Discus articularis 



2ri_ Processus condyloideus 



Pterygoideus externus 



/ 



Fig. 72. — The temporomandibular articulation. 



The mandible articulates with the glenoid fossa and its anterior edge or emi- 
nentia articularis of the temporal bone. Interposed between the condyle below and 
the bone above, is an interarticular cartilage. This divides the articulation into 

two portions, an upper and a lower. The ligaments 
are a capsular, strengthened by an external lateral 
(temporomandibular) and an internal lateral. The 
capsular ligament is weakest anteriorly and strongest 
on the outer side. The thickening of the capsule 
on its outer side forms the external lateral or tem- 
poromandibular ligament. The sphenomandibular 
or internal lateral ligament is practically distinct 
from the articulation. It runs from the alar spine 
on the sphenoid above to the mandibular spine or 
lingula, just posterior to the mandibular foramen 
below. Between it and the neck of the bone run 
the internal maxillary artery and vein. When the 
condyle glides forward it puts the posterior portion 
of the capsule on the stretch, and if the jaw is dislocated this part of the capsule is 
torn. The interarticular cartilage is more intimately connected with the lower por- 
tion of the articulation. The same muscle that inserts into the neck of the jaw (the 
external pterygoid) likewise inserts into the cartilage ; therefore, the two move 
together, so that when the condyle goes forward the cartilage goes forward and rides 
on the eminentia articularis. 




Fig. 73. — External lateral ligament of the 
lower jaw. 



THE FACE. 



65 




Fig. 74- 



Illustrating up-and-down or pure hinge motion 01 
the mandible. 



Movements of the Jaw. — The jaw has four distinct movements. It can be 
moved directly forward or backward; up and down, a pure hinge motion; a rotary- 
movement on a vertical axis through one of the condyles; and rotation on a trans- 
verse axis passing from side to side 
through the mandibular or inferior 
dental foramina. The muscles of mas- 
tication are the temporal, massder, 
and ptoygoids ; these are sujiplied by 
the motor branch of the fifth nerve. 
To these we may add the buccinator, 
which is supplied by the seventh nerve, 
and the depressors of the jaw, — the 
digastric, geniohyoid, geniohyoglos- 
sus, mylohyoid, and platysma. The 
posterior belly of the digastric receives 
its nerve supply from the facial ; its 
anterior belly from the mylohyoid 
branch of the inferior dental from the 
fifth. The mylohyoid is supplied by 
the mylohyoid branch of the inferior 
dental. The geniohyoid and genio- 
hyoglossus are supplied by the hypo- 
glossal nerve. The platysma is sup- 
plied by the inframandibular branch 
of the facial nerve. The upward move- 
ment is produced mainly by the mas- 
seter and temporal muscles. It is the 
principal movement in carnivorous 
animals ; therefore, these muscles in 

them are well developed, and the joint is a pure hinge joint. The internal pterygoid 
and buccinator likewise aid in closing the mouth ; the depressors already mentioned 
open it. The lateral or rotary movement around a vertical axis passing through one 

condyle is used in chewing ; therefore, we 
find the muscles most concerned, the ptery- 
goids, best developed in herbivorous ani- 
mals, or those which chew the cud. The 
external pterygoid is especially efficient in 
pulling the jaw forward ; superficial fibres 
of the masseter help in this. The posterior 
fibres of the temporal muscle pull the jaw 
back, as do likewise the depressor muscles 
of the jaw. In this rotary movement one 
condyle remains back in its socket while the 
other is brought forward on the eminentia 
articularis. 

The up-and-down movement of the 
jaws, when limited in extent, is a pure hinge 
movement without any anteroposterior dis- 
placement, and takes place between the con- 
dyle and the interarticular cartilage (Fig. 
74). The anteroposterior movement is 
necessarily accompanied by a slight descent 
of the jaw, as the condyle ghdes from 
the glenoid cavity (F"ig. 75) onto the emi- 
nentia articularis. It goes nearly, but not 
quite, to the highest point of the articular 
If the jaws are kept closed during this anteroposterior movement, some 
of the teeth of the upper and lower jaws will still be in contact, the number varying 
in different individuals '-^ « • 

5 




Fig. 75. — Illustrating direct anteroposterior move- 
ment of the mandible. The condyle is resting on the 
eminentia articularis. 



eminence. 



The last molar teeth are usually higher than those in front, 



66 APPLIED ANATOMY. 

so that as they glide forward the last lower molars strike the second upper ones. 
The incisors likewise can be kept in contact as the jaw moves backward and forward. 
It is this movement in the rodent animals which keeps their edges sharp. In chew- 
ing, the jaw is depressed, the teeth separated, and the food held between them by the 
tongue and buccinator muscle. The teeth are then approximated by the lower jaw 
closing and the condyle sliding upward and backw^ard from the eminentia articularis 
into the glenoid cavity, carrying with it the articular cartilage. 

The hinge motion takes place between the condyle and the interarticular carti- 
lage. The anteroposterior motion takes place between the interarticular cartilage and 
the eminentia articularis: the cartilage is carried forward with the mandible. A rotary 
movement occurs when, in chewing, the condyle of one side remains in the glenoid 
cavity while that of the other rises on the articular eminence. The radius of rotation 
is a line passing from one condyle to the other. In widely opening the mouth, as 
in yawning, the condyles are tilted forward while the angles of the mandible are 



Temporal muscle 




External lateral ligament 



Internal pterygoid muscle 



Masseter muscle 



Fig. 76. — Dislocation of the lower jaw ; the zygoma and part of the masseter muscle have been cut away. 

carried somewhat backward. As the axis of this motion passes from side to side 
through the mandibular foramina, this portion of the bone moves but little, and the 
inferior dental vessels and nerve are not put on the stretch. 

Dislocation of the Lower Jaw. — The forward dislocation is practically the 
only one to which the jaw is subject. Dislocations in other directions are apt to be 
accompanied by fractures. An understanding of the mechanism of the production 
and reduction of this dislocation requires a knowledge of the movements of the jaw, 
and the influences which the ligaments and muscles exert in limiting them. The 
normal movements of the jaw have already been discussed. 

The ligaments which limit the movements of the jaw are those forming the cap- 
<sular Hs;ament. This is made up of four parts: anterior, posterior, internal lateral, 
and external lateral. The anterior is very weak, hence pus in the joint is most apt 
to make its exit forwards. It is readily ruptured in dislocations. The posterior 
ligament, though stronger, may also be torn. The two lateral ligaments, the outer 
being the stronger, become tense when the condyle slips forward on the articular 
eminence. In dislocation they remain attached to the mandible and are not rup- 
tured (see Fig. 76). 



THE FACE. 



67 



Dislocation occurs when the mouth has been widely opened and the condyles 
are forward on the articular eminences. Some sudden jar accompanied by contrac- 
tion mainly of the external pterygoid muscle causes the condyle to slip forward just 
in front of the articular eminences. The pterygoid muscles and the superficial fibres 
of the masseter muscles aid in producing the luxation. As the condyle leaves 
the articulation to jump forward, it will be noted that it does so by an extensive 
movement, which is one of rotation on a transverse axis passing across in the 
region of the mandibular foramina. The condyle once out of its socket is kept 
out by the contraction of the temporal, masseter, and internal and external pterygoid 
muscles. 

Reduction of Dislocation of the Lower Jaw. — In reducing the dislocation, 
the condyles must be depressed and pushed back. This can be done by one of two 
ways: viz., the thumbs of the surgeon, being protected by wrapping with a towel or 
bandage, are placed on the last molar teeth, and the jaw firmly grasped with the 
fingers beneath it. The back part of the jaw is then pressed downward, the chin 
tilted upward, and the condyles slid back into place. 




Small fragment into which 
was inserted the g^eiiiohyoid 
and geniohyoglosbus muscles 

Fig. 77. — Fracture of the mandihle through the symphysis (author's sketch). 



The other method is to place two corks, one on each side, or a piece of wood, 
transversely, between the last molar teeth, then raise the chin and push it backward. 

The undetached lateral ligaments are put on the stretch when the condyle is 
luxated forward. Lewis A. Stimson believes that in attempting reduction the jaw 
should first be opened wider to relax these and then pushed back, but we are 
not prepared to admit that so doing does relax these ligaments. He has, however, 
shown that the interarticular cartilage may become displaced and, by filling up the 
articular cavity, prevent a proper reduction. In rare instances the catching of the 
coronoid process beneath the malar bone may hinder replacement. 

Fractures of the Lower Jaw f Mandible). — Fractures of the lower jaw 
almost never occur through the symphysis; this is on account of its being the thickest 
and strongest part of the bone. When a fracture of the anterior portion of the jaw 
detaches a median piece a most dangerous condition is produced. The piece, if 
sufficiently loosened by the injury, is drawn back into the throat, carrying the tongue 
with it and tending to suffocate the patient. Such a case is recorded by A. L. 
Peirson (review by Geo. W. Norris, Amer. Jour. Med. Scietices, 1841, N. S. vol. i, 
p. 186). A man was run over by a wheel which passed over his jaw, fracturing it 
on each side and forcing the piece into his moiith. The piece was drawn backward 
and nearly caused death from suffocation. 



68 



APPLIED ANATOMY. 



In the Annals of Surgery (vol. xix, 1894, p. 653) is recorded a case of the 
author's in which a man, while drunk, fell and struck his chin on the curbstone. A 
fracture was produced through the symphysis above and branching to each side of 
the genial tubercle below. This small median piece was drawn back into the throat 
nearly to the hyoid bone, and suffocative symptoms were marked. These disap- 




Geniohyoid muscle Geniohyoglossus muscle 
Fig. 78. — Anteroposterior section of the tongue and floor of the mouth, near the midline. 

peared when the detached piece was drawn forward and wired in place. The piece 
was drawn backward by the geniohyoid and geniohyoglossus muscles. The digas- 
trics may also have aided in depressing the fragment (Figs. 77 and 78). 

The most usual site of fracture is in the neighborhood of the mental foramen. 
This is located just below the second premolar tooth (sometimes between the first 
and second). This foramen and the large socket for the canine tooth farther 



Temporal muscle 



Masseter muscle 




Buccinator muscle 



A 



Mylohyoid muscle 

Digastric muscle 

Fig. 79. — Fracture of the lower jaw in the region of the mental foramen, showing the line of fracture and the influ- 
ence of the muscles in producing displacement. 

forward weaken the bone somewhat in this region. The jaw is strengthened behind 
the mental foramen by the commencement of the anterior portion of the ramus and 
by an increase in the size of the mylohyoid ridge on the inner surface. The jaw is 
also protected by the thick masseter muscle and fracture is most liable to occur just 
in front of it. This constitutes the typical fracture of the lower jaw (Fig. 79). 



THE FACE. 



69 




Fig. 80. — Fracture of the lower jaw, showing 
the Hne of fracture proceeding downward and 
backward, favoring displacement. 



Displacement. — The displacement of the fragments will depend on the line of 
fracture; and the line of fracture may be determined by the direction and character of 
the fracturing force. The line of fracture is oblique. It may be oblique from above 
down or from without in. An examination of the muscles attached to the mandible 
will show that the elevators of the jaw are attached to it posteriorly and its depres- 
sors anteriorly. On this account, when the fracture runs obliquely down and 
forward there is little or no displacement, because the depressors and elevators tend to 
press the fragments together. When the fracture 
runs downward and backward (see Fig. 80), the 
depressors and elevators tend to separate the 
fragments. The depression of the anterior frag- 
ment is particularly marked when the fracture is 
double, involving both sides of the jaw. The 
muscles which tend to depress the anterior frag- 
ment are the geniohyoglossus, geniohyoid, mylo- 
hyoid (anterior portion), digastric, and platysma. 
The muscles which elevate the posterior frag- 
ment are the temporal, masseter, buccinator, and 
internal pterygoid. 

The displacement may not only be up and 
down, but may also be lateral. The line of frac- 
ture may run from the outside either inward 
and backward or inward and forward. The jaw is held in place by its own rigidity 
when intact ; when broken, the smaller fragment is liable to be pulled inward by the 
muscles passing from it toward the median line. These muscles are the internal 
pterygoid and the mylohyoid. The influence of the former is more marked than of 
the latter, because the fracture frequently divides the mylohyoid, leaving a part of 
it attached to each fragment. When the fracture passes from without inward and 

backward, then there will be little or no 
displacement, because the internal ptery- 
goid and mylohyoid draw the fragments 
together. (See Fig. 81.) When the 
line of fracture is from without inward 
and forward, the internal pterygoid of 
the injured side and the mylohyoid draw 
the posterior fragment inward, while the 
internal pterygoid of the opposite side 
draws the anterior fragment outward 
(Fig. 82). 

From a consideration of the forego- 
ing facts, we see that when there is dis- 
placement it is because the fracture runs 
from above downward and backward, 
and from without inward and forward. 
The anterior fragment is displaced down- 
ward and the posterior fragment is dis- 
placed inward. 

Fractures through the region of the 
molar teeth are not particularly uncom- 
mon, and this is likewise the case with fractures obliquely downward and outward 
through the angle of the jaw. In these injuries the firm attachment of the masseter 
on the external surface of the jaw and the internal pterygoid on its inner prevent 
displacement. 

Fractures of the coronoid process are exceedingly rare. In them displacement 
is prevented by the attachment of the temporal muscle, which passes much farther 
down on the inside than on the outside. 

Fractures of the neck of the jaw are particularly serious. Inserted into the 
condyle and neck of the jaw is the external pterygoid muscle. When a fracture of the 
neck occurs, this muscle pulls the upper fragment anteriorly and tends to tilt its 




Fig. 81. — Fracture of the jaw, showing absence of dis- 
placement when the line of fracture runs from the inside 
forward and outward. 



70 



APPLIED ANATOMY. 



upper end inward. This displacement is so marked that an excessive amount 
of callus is thrown out and ankylosis may result. This so seriously interferes 




FiG 82. — Fracture of the jaw, showing the action of the internal pterygoid and mylohyoid muscles in producing 
displacement when the line of fractuie runs from the outside forward and inward. 

with the use of the jaws as to justify an operation to remove or replace the upper 
fragment in proper position. The injury is liable to be overlooked in children, and 
as they grow up the deformity shown in Fig. 83 develops. 




Fig. 83. — Deformity of the face following ankylosis due to fracture of the neck of the lower jaw in infancy (from an 

original sketch). 

Treatment. — The lower jaw is held up in place by a bandage, and the upper 
teeth act as a splint. Sometimes the teeth or fragments are wired in position, or an 
interdental splint of gutta percha or other material is used. 



THE FACE. 



n 



Excision of the Condyle of the Jaw. — The condyle can be removed 
through an incision 3 cm. long, running from in front of the ear along the lower border 
of the zygoma. The temporal artery runs a centimetre in front of the ear with the 
auriculotemporal nerve posterior to it. By care in recognizing the artery, it may be 
saved and dragged posteriorly. The soft parts on the lower side of the wound with 
the parotid gland and facial nerve are pushed downward. The condyle can then 
be dug out, care being taken not to go beyond the bone and wound the internal 
maxillary artery. 

Excision of the Mandible. — In removing one-half of the mandible, the 
incision is made from the symphysis along the lower border of the jaw to the angle 
and thence upward as high as the lobe of the ear. If it is desired to take extra 
precautions, the last centimetre of this incision, from the lobule of the ear down, may 
be carried through the skin only. This will prevent wounding to any great extent 
the parotid gland tissue, the parotid duct, and positively avoid injuring the facial 
nerve. The incision, however, is rather far back to wound any large branch of the duct, 
and is too low down to wound the facial nerve. If it is desired to carry the incision 
higher than the lobule of the ear, it should go through the skin only. The facial 
artery and vein will be cut just in front of the masseter muscle. The soft parts. 




Fig. 84. — Excision of the condyle of the lower jaw. 



including the masseter muscle, are raised from the outer surface. In dividing the 
bone anteriorly, it should be done .5 cm. outside the median line. This will be 
about through the socket of the second incisor. The object of this is to retain the 
attachments of the genioliyoid and geniohyoglossus muscles to the genial tubercles, 
and so prevent any tendency of the tongue to fall back. The jaw is pulled out and 
separated from the parts beneath, the mylohyoid muscle being made tense. Care 
should be taken not to injure the submaxillary gland, which lies below the mylohyoid 
muscle, and the sublingual gland, which lies above it. The lingual nerve is also liable 
to be wounded if the knife or elevator is not kept close to the bone. 

As the detachment proceeds posteriorly, in loosening the internal pterygoid and 
the superior constrictor, if care is not taken, the pharynx may be wounded. The 
bone still being depressed and turned outward, the temporal muscle is to be loosened 
from the coronoid process or else the process is detached and removed later. Access 
is now to be had to the mandibular foramen at the mandibular spine or spine of Spix. 
The inferior alveolar artery is then secured and, with the nerve and sphenomandibular 
ligament, divided. The jaw can now be well depressed and brought inward. The 
temporomaxillary joint is to be opened from the front, having first cleared off the 
attachment of the external pterygoid muscle. There is great danger of wounding 
the internal maxillary artery at this stage of the operation. It lies close to the neck 



72 



APPLIED ANATOMY. 



of the jaw, and it is to avoid bringing it too close to the bone that Jacobson advises 
that the jaw be not twisted outward when disarticulation is being performed. 

The distance between the coronoid process and malar bone varies in different 
individuals. The process may be displaced by the tumor and thus prevent detachment 
of the temporal muscle. If so, the process is divided with forceps or saw and removed 
after the rest of the jaw has been taken away. Injury of the temporomaxillary veins 



Tongue 



Geniohyoglossus muscle 
Geniohyoid muscle 
Mylohyoid muscle 



Anterior belly of 
digastric muscle 




Masseter muscle 
Lingual nerve 



Muscular branches 
of internal maxil- 
lary artery 

Inferior alveolar 
(dental ) nerve and 
artery 
.Internal pterygoid 
muscle 
Duct of submaxillary 
gland 
Facial vein 



Facial artery 
Sublingual gland 
Fig. 85. — Excision of one-half of the lower jaw, showing the structures exposed. 

may be avoided by not going behind the posterior edge of the ramus, as is also the 
case with the external carotid artery. Access to the joint may be facilitated by drag- 
ging upward the parotid gland, which carries with it the facial nerve and parotid duct. 



REGION OF THE EYE. 

The eyeball rests in its socket, which is hollowed out of the soft parts contained 
in the bony orbit. It is covered in front by the lids, which, as they slide over the 
eye, are lubricated by the tears. These are secreted by the lachryynal gland at the 
upper outer portion of the orbit, flow over the eye, and are drained off by the lach- 
rymal canals and sac to empty into the nose through the lachrymonasal duct. 

The Orbits. — The orbits are large four-sided cavities, pyramidal in shape. 
The orbit in an adult male is about 4 cm. in diameter from side to side, and 3.5 cm. 
from above downward. The depth is 4. 5 cm. It is thus seen that the orbit is wider 
than it is high. On receding into the orbit from its bony edge, the roof arches 
upward toward the brain to receive the lachrymal gland, thus making the up-and- 
down diameter slightly longer than the transverse. 

The rim of the orbit is very strong and not readily broken by injuries. It is 
formed by the frontal bone above, the malar bone to the outside, the malar and supe- 
rior maxillary below, and the superior maxillary and frontal to the inside. The 
inner (medial) walls of the two orbits are parallel, running distinctly anteroposte- 
riorly. The outer (lateral) walls diverge at an angle of about 45° from the inner ones. 

The outer or lateral edge of the orbit is nearly or quite a centimetre and a half 
posterior to the inner or medial edge. This fact, together with the divergence of the 
outer wall, is the reason that, in enucleation of the eye, it is always tilted toward the 
nose, and the scissors introduced and the nerve cut from the outer side. 

The oviter wall of the orbital cavity is formed mainlv by the broad flat surface of 
the greater wing of the sphenoid bone, and is thick and strong. The other three 



REGION OF THE EYE. 



73 



walls, on the contrary, are thin and weak. The thin orbital plate of the frontal bone 
above is frequently fractured in puncture wounds by foreign bodies, and the frontal 
lobe of the brain injured. Two such instances have come under the writer's care; 




Supra-orbital notch 

Lachr>'inal groove 
Optic foramen 



Sphenoidal (superior 
orbital) fissure 



Sphenomaxillary (In- 
ferior orbital) fissure 



Fig. 86.— The bony orbit. 



Infra-orbital sulcus 



Infra-orbital foramen 



in the first case, an iron hook had penetrated and caused death from cerebritis ; in 
the second, the wound was caused by a carriage pole. The patient recovered, 
notwithstanding a considerable loss of brain tissue. 



Sphenoidal sinus 



Inferior orbital 
fissure 



Infra-orbital sulcus 

Ethmoidal cells 
— Lachrjmal canal 

Nasal septum 




Fig. 87. — Transverse section of the orbital and nasal cavities viewed from above. 

To the medial side of the inner wall are the ethmoid cells, covered by the thin 
lachrymal bone and the os planum of the ethmoid. They are readily perforated by 
suppuration from within those cavities. The floor is chiefly formed by the thin 



74 



APPLIED ANATOMY. 



orbital plate of the superior maxilla. In operations involving the floor of the 
orbit, care is necessary to avoid breaking through into the maxillary sinus (antrum) 
beneath. 

At the edge of the junction of the outer and lower walls lies the inferior orbital 
(^sphe7iomaxillary) fissure. It runs forward to within 1.5 cm. of the edge of the 
orbit and extends back to the apex of the orbit, where it unites with the superior 
orbital {^sphenoidal) fissure, which lies between the roof and outer wall and extends 
forward about one-third of the distance to the edge of the orbit. The optic fiora men 
enters the apex of the orbit at its upper and inner portion. 

At the lower inner edge of the orbit is the lachrymal groove for the lachrymo- 
nasal duct, leading from the eye to the inferior meatus of the nose. At the junction of 
the middle and inner thirds of the upper edge is the supra-orbital notch. This can 
be felt through the skin. It transmits the supra-orbital artery and 7ierve. If a 
complete foramen is present instead of a notch, its location cannot be so readily 
determined. 

Contents of the Orbit. — The orbit is lined with a periosteum, and contains 
the eyeball, the muscles which move it, the veins, arteries, and nerves which go to 



Superior oblique muscle 

Superior orbitotarsal 

ligament 

Levator palpebrse 

superior muscle 

Superior rectus muscle 
Tarsal cartilage 



Inferior rectus muscle 
Inferior oblique muscle 



Capsule of Tenon 



Inferior orbito- 
tarsal ligament 




Fig. 88. — Sagittal section through the eye and orbit. 



it together with some which traverse the orbit to go to the face, and the lachrymal 
gland. These structures are more or less surrounded with a fascia which is continu- 
ous with the periosteum. 

Periosteum. — The periosteum of the orbit is not tightly attached and in cases 
of disease can readily be raised from the bone beneath. Anteriorly, it is continuous 
at the orbital rim with the periosteum of the bones of the face. Posteriorly, it is con- 
tinuous through the optic foramen and sphenoidal fissure with the dura mater. 
It sends prolongations inward, covering all the separate structures in the orbit. 
From the edge of the orbit it stretches over to the tarsal cartilages, forming the 
superior and inferior orbitotarsal ligaments. These form a barrier (called the sep- 
tum orbitale) to the exit of pus from within the orbit, and for that reason it is advised 
that orbital abscesses should be opened early. The lower portion, as it reaches 
the lachrymal groove, splits to cover the lachrymal sac. Another extension 
from above splits to enclose the lachrymal gland, which is seen to lie comparatively 
loose in the upper outer portion of the orbit, sustained by its suspensory ligament. 
It then sends thin fibrous layers which cover the muscles, arteries, veins, nerves, fat 
pellicles, and finally the eyeball posterior to the insertion of the muscles and optic 
nerve. This last portion, called the capsule of Tenon, begins as far forward as the 



REGION OF THE EYE. 



75 



insertion of the recti muscles on their under (inner) side, passes over the globe poste- 
riorly, over the optic nerve, and blends with the layer covering the deep surface of the 
muscles. It is joined to the sclerotic coat of the eye and dural sheath of the nerve 
by a loose net-work of delicate fibrils. This forms practically a space lined with 
endothelial plates, similar to the subarachnoid space in the brain. The capsule of 
Tenon is a distinct, well marked membrane, and the eyeball lies loose and revolves 
freely within it. It is this space into which the strabismus hook is put when it is 
desired to cut the recti muscles for squint. Fibrous prolongations are also sent 
to the sides of the orbit from the internal and external recti muscles. They are 
the check ligaments; and one from the inferior rectus forms the suspensory ligament 
of the eye. 

Affections of the Orbit. — The orbit is often invaded by tumors, pus, hemor- 
rhages, and air (producing emphysema). 

Tu77ioi'S may either originate in the orbital contents, as sarcomas of the lach- 
rymal gland or eye, or they may come from surrounding regions. It is more rare 
for them to enter through the natural openings of the orbit than it is for them to 
push through its thin walls. Coming through natural openings, they may make 
their entrance : (i) from the brain through the optic foramen or sphenoidal fissure ; 

(2) from the region of the zygomatic and temporal fossae through the sphenomaxil- 
lary fissure ; (3) from the nasal cavities 

(as I have seen), coming up the lachry- 
monasal canal. 

In invading the orbit through its walls 
they may come: (i) from the nasal cavi- 
ties and ethmoidal cells, pushing through 
the thin internal wall ; (2) from the frontal 
sinus, appearing at the upper inner angle; 

(3) from the sphenoidal cells at the pos- 
terior portion of the inner wall ; (4) from 
the brain cavity above, breaking through 
the roof ; (5) from the maxillary sinus 
below, pushing through the floor. 

Dermoids. — In the foetus, the fronto- 
nasal process comes from above down- 
ward to join the maxillary processes on 
each side. This leaves an orbitonasal cleft to form the orbit. Owing to defects in the 
development of this cleft, dermoid tumors may occur in its course. They are seen 
either at the outer or inner angle of the eye. They are more common at the outer 
angle near the external angular process, and may have a prolongation to the dura 
mater. They also occur at the inner angle at the frontonasal suture (Fig. 89). At 
this point, also, meningoceles are liable to occur. As pointed out by J. Bland Sutton 
the question of diagnosis is of importance, as an attempt to remove a meningocele 
by operation is apt to be followed by death, whereas a dermoid, though it may have 
a fibrous prolongation to the dura mater, can be more safely removed. 

Orbital Abscess. — Suppuration may either originate within the orbit or extend 
into it from the neighboring tissues. If the former is the case, it may occur from 
caries of the bones of the orbit, as in syphilis. It may originate from erysipelas 
involving the orbit. General inflammation and suppuration of the eye may break 
through the eye and spread in the orbital tissues (panophthalmitis). If pus enters 
the orbit from the outside, it is usually from suppuration and caries of the frontal 
sinus and ethmoidal cells. In this case, the swelling shows itself at the upper 
portion of the inner angle of the eye. Pus in the maxillary sinus is most apt to 
discharge into the nose, and not break through the roof into the orbit above. 
Pus within the orbit tends to push the eyeball forward and even distend the lids. 
As the orbitotarsal ligament runs from the bony edge of the orbit to the lids, pus 
does not find an easy exit. The abscess should be opened by elevating the upper 
lid, and incising the conjunctiva in the sulcus between the globe of the eye and the lid. 
Pus from suppuration of the lachrymal sac does not tend to invade the orbit but 
works its way forward to the skin. 




Fig. 89. — Dermoid of orbit. Boy, 15 years of age. It 
extended back to the body of the sphenoid bone. Case of 
Dr. Wm. Zentmayer. 



76 



APPLIED ANATOMY. 



Foreig?i Bodies i7i the Orbit. — Owing to the considerable space which exists 
between the eye and orbital walls, large foreign bodies may find a lodgment there, 
often producing serious symptoms for a considerable length of time. The tang of 




Fig. 90. — Lines of the skin incision. (Kronlein's operation for obtaining access to the retrobulbar region.) 



a gun barrel has been so found. This should lead one to search for foreign bodies 
carefully when this portion of the orbital contents has been wounded. 



Periosteal lining of orbit Incision 




Fig. 91. — The rim of the orbit has been divided and the piece of the bone turned outward ; an incision is then made 
through the periosteal lining. (Kronlein's operation for obtaining access to the retrobulbar region.) 



Emphysema. — In cases of fracture involving the inner wall and opening up the 
nasal cavities or sinuses the air, particularly in blowing the nose, may be forced into 



Periosteal lining 



Stump of rectus externus muscle 



Rectus externus cut and turned back 




Bulb of eye 
Optic nerve 



Fig. 92. — The edges of the incised periosteum have been separated and the external rectus muscle divided, exposing 
the space posterior to the bulb. (Kronlein's operation for obtaining access to the retrobulbar region.) 

the orbit, distending the lids and producing a peculiar crackling sensation when 
palpated. No treatment directed to removal of the air is necessary. It is valuable 
as a diagnostic sign of fracture communicating with the nasal cavities. 



REGION OF THE EYE. 



77 



Hemorrhage. — Hemorrhage into the orbit may occur either as the resuh of 
direct traumatism inxolving the contents, or from fracture of the base of the skull 
through the orbital plate. The blood pushes its way anteriorly and shows itself 
under the conjunctiva surrounding the cornea. It is prevented from appearing 
on the lids by the orbitotarsal ligament. A subconjunctival hemorrhage alone is not 
sufficient to justify a diagnosis of fracture of the base of the skull, although it is 
a significant confirmatory symptom. 

Kronlein's Operation. — In order to gain access to the back part of the orbit 
to remove tumors, Krbnlein resects the outer wall, divides the periosteum and 
external rectus muscle, and so gains access to the retrobulbar space. The various 
steps of the operation are shown in Figs. 90, 91, 92. 

THE EYEBALL AND OPTIC NERVE. 

The eyeball has three main coats, viz. : a fibrous outer coat, called the sclerotic; 
a vascular middle coat, the choroid ; and a nervous inner coat, the retina. 

Sclerotic Coat. — The sclerotic coat forms a firm protective covering or case 
for the delicate retina within. It is continuous posteriorly with the fibrous coat or 
dura of the optic nerve, which is a continuation of the dura mater of the brain. At 
the optic foramen, the dura mater splits into two layers; the outer layer forms the 
periosteum, while the inner forms the dural coat of the optic nerve. This nerve also, 
like the brain, has an arachnoid and a pial membrane. The sclerotic coat is con- 
tinued forward over the front of the eye as the cornea. As it is essentially a mem- 
brane intended to be protective in its function, its diseases are those of weakness: 
thus, if the cornea is affected, it bulges forward and is called an anterior staphyloma ; 
if the posterior part is affected, the sclera is stretched, and it forms a posterior 
staphyloma. 

Anterior staphyloma may occur either rapidly as a small local protrusion, resulting 
from ulceration of the cornea or a wound, or it may be slow in forming, and in\'olve 
nearly or quite the whole of the cornea, pushing it forward in the shape of a cone; 
this is called conical coniea. Posterior staphyloma occurs in near-sighted people, the 
anteroposterior diameter of the eye being longer than normal. If this posterior 
staphyloma or stretching of the eye becomes marked, the choroid atrophies and the 
functions of the retina are lost. The white sclera is seen with the ophthalmoscope, 
surrounding or to one side of the optic nerve. 

Although the cornea has no blood-vessels, it still, from its exposed position, 
becomes inflamed {keratitis') and ulcerated, and eventually blood-vessels may de- 
velop into it from its periphery, constituting the disease known as pannus. 

The weakest portion of the globe is at the junction of the sclerotic coat with the 
cornea. It is here that the sclera is thinnest. On this account, blows on the eye 
cause it to rupture usually at this point, the tear encircling the edge of the cornea 
for a variable distance (usually at its upper and inner quadrant) according to the 
force and direction of the injury. On healing, a staphyloma may form at this point. 

The choroid or vascular coat of the eye contains the pigjnent or color of the 
eye. It is continued forward as the ciliary body (or processes) and iris. Being a 
vascular tissue, its diseases are inflammatory. If the choroid is affected we have 
choroiditis; if the ciliary region is inflamed, it is called cyclitis ; and if the iris is 
inflamed we have iritis. 

The retina or nervous coat of the eye is concerned in the function of sight and 
it, like other nerves, may be affected with inflammation, called retinitis. Sometimes 
it becomes loosened from the choroid beneath by a hemorrhage or rapid stretching 
of the sclera, constituting a detachment of the retina. Outside the disk is the macula 
lutea and fovea centralis or region of distinct vision. 

Filling the interior of the eye is the jelly-like transparent vitreous hiwior^ enclosed 
in the hyaloid membrane. In front of the vitreous humor is the lens; and the clear, 
limpid liquid between the anterior surface of the lens and the posterior surface of the 
cornea is the agueoiis humor. 

The lens, immediately behind the iris, is suspended in. its capsule from the 
ciliary processes by its suspensory ligament or zone of Zinn. Between the ciliary 
processes and the sclera lies the ciliary muscle, which regulates the accommodation 



78 



APPLIED ANATOMY. 



or focussing power of the eye. The ciliary processes are formed of convolute! 
blood-vessels supported by connective tissue and covered by the pigmented exten- 
sion of the retina. This ciliary region is an exceedingly sensitive one and a serious 
wound of it usually means a loss of the eye. 

Cataract. — When the lens is opaque it constitutes the disease known as cata- 
ract: this name is also applied to opacities of the capsule of the lens. When the lens 
alone is opaque it is called a le7iticular cataract; when the capsule alone is affected, it 
is a capsular cataract. Both are sometimes involved, constituting a lenticiilocapsular 
cataract. The lens is made up of layers like an onion. Some of these layers may 
become opaque, leaving a surrounding rim of clear tissue. The nucleus within the 
affected layer is also clear. This form is called a zonular or lamellar cataract. A 
capsular cataract may affect the anterior portion of the capsule, forming an anterior 
polar cataract^ or the posterior layer of the capsule, forming a posterior polar cataract. 

If the cornea has been perforated by a central ulceration, the aqueous humor 
escapes, the lens falls forward, and its anterior capsule becomes adherent at the site 



Lens 



Suspensory ligament of lens 
Canal of Schlemm 
Ciliary process 

Conjunctiva 



Cornea 

Anterior chamber 
Iris 

Posterior chamber 

Sclerocorneal juncture 



Tendon of in 

ternal rectus 

muscle 

Vena vorticosa 




Tendon of 
-external rectus 
muscle 



Vitreous 



Sclera 



Ciliary nervi 

Posterior ciliary vessels 

Hyaloid canal 

optic nerve 

Central retinal vessels 



Choroid 



Retina 
Fovea centralis 



Fig. 93. — Diagrammatic horizontal section of right eye. X 3^^- (Piersol.) 



of perforation. As the aqueous humor reaccumulates, it pushes the lens back, leaving 
a small portion of inflammatory tissue clinging to its anterior capsule, thus forming 
an anterior polar cataract. A posterior polar cataract is the result either of disease, 
such as choroiditis^ in which the posterior capsule becomes involved, or of a persistence 
of the remains of the hyaloid artery, a fetal structure. 

Secondary cataracts are the opacities of the capsule or inflammatory bands 
and tissues which are left, or which occur, after the removal of the lens. The lens in 
childhood is soft; it grows harder as age increases. If the aqueous humor obtains 
access to the lens through a wound of the anterior capsule, the lens becomes opaque, 
constituting a traumatic cataract. In operating for cataract in childhood, the lens, 
being soft, is first rendered opaque by the aqueous humor admitted through a 
puncture made in the capsule ; if it is admitted repeatedly to the lens by the 
surgeon's needle (needling or discission operation) the lens matter is completely 
dissolved. The fluid lens matter can also be removed by a suction instrument. 
In old people the nucleus becomes hard and opaque, forming a senile cataract. 



REGION OF THE EYE. 



79 



The aqueous humor does not dissolve the opaque lens after the aj^e of thirty five 
years. Senile cataract rarely occurs before the forty-fifth year, so there is a period 
of ten years in which a cataract may be a nuclear cataract without being senile. 

To remove a nuclear or a senile cataract, a slit is made through the cornea near 
its scleral junction, a piece of the iris may (or may not) be removed, the anterior 
capsule is cut with a cystotome and the opaque lens pressed out through the 
opening so made, then through the pupil (either artificial or dilated with atropine), 
and finally through the sclerocorneal incision. The posterior capsule is not injured, 
and it prevents the vitreous humor from escaping. If inflammation follows the 
operation, the iris and ciliary region throw out lymph and the remains of the 
capsule become opaque, forming a secondary or capsular cataract. This is removed 
by tearing or cutting it across with needles or extremely fine scissors. 

Iris. — The iris is the continuation of the choroid through the ciliary body, and 
extends down to the pupil, its free edge resting on the anterior surface of the lens. 
The iris is composed of a vascular and fibrous anterior portion, and a muscular and 
pigmented posterior portion. In consequence of its vascularity, the iris is the fre- 
quent site of inflammation. When inflamed it pours out lymph which may cause it 
to adhere to the lens behind, forming a posterior synechia. An anterior synechia is 
where, on account of a perforation of the cornea, the iris washes forward and becomes 
attached to the cornea in front. 

The circular muscle fibres surrounding the pupil are anterior, and form the 
sphincter piipillcE muscle ; it contracts the pupil. The radiating muscular fibres, 
which lie posteriorly, form the dilator piipillce ; it dilates the pupil. The dark pig- 
ment layer is on the posterior surface of the iris, and after an attack of iritis, as the 
adherent iris is torn loose from the lens, it leaves patches of pigment adhering to the 
anterior capsule. 

The iris, as it rests at its pupillary margin on the lens, divides the space anterior 
to the lens into two parts. The part between the posterior surface of the iris and the 
anterior surface of the lens forms the posterior chamber. The anterior chamber lies 
between the anterior surface of the iris and the posterior surface (^Descemet^ s mem- 
brane) of the cornea. The two chambers communicate through the pupil. The 
anterior surface of the iris toward its periphery is of the nature of a coarse mesh- 
work, the spaces of which are the spaces of Fonta^ia. They communicate with a 
venous or lymph canal which passes around the eye at the sclerocorneal junction 
(^canal of Schlemm ). 

Aqueous Humor and Anterior Lymph Circulation, — The aqueous humor 
is of the nature of lymph. It is secreted by the ciliary processes and posterior surface 
of the iris. It passes through the pupil to the anterior chamber, and enters the 
spaces of Fontana to empty into the canal of Schlemm. The canal of Schlemm 
empties its contents into the anterior ciliary veins. In iritis and glaucoma the lymph- 
current is seriously interfered with. In iritis, the swelling and outpouring of lymph 
blocks the spaces of P^ontana and prevents a free exit of the aqueous humor from 
the anterior chamber, therefore in this condition the anterior chamber is deep, and 
the iris is seen to lie far beneath the cornea. 

Glaucoma. — Glaucoma is a disease accompanied by increased intra-ocular 
tension. The eyeball feels hard to the touch. It is supposed to be due to disease 
of the ciliary region interfering with the canal of Schlemm and obstructing it. 
Therefore, the drainage of the eye and the circulation of the aqueous humor is inter- 
fered with. In iritis the anterior chamber becomes deeper, but in glaucoma, as the 
intra-ocular tension increases, it pushes the lens forward, and it is seen to lie close 
up to the cornea; so that a shallow anterior chamber causes the ophthalmologist to 
suspect glaucoma and a deep anterior chamber iritis. The increased pressure within 
the eye pushes the optic nerve backward at its point of entrance, so that it is seen 
sunk below the surface of the adjoining retina, forming a distinct cup-shaped cavity 
or pit. This is cuppino; of the disk. 

Optic Nerve. — The optic nerve reaches from the optic chiasm, to the eyeball, a 
distance of about 5 cm. f 2 in. ) . It enters the apex of the orbit through the optic foramen 
at the upper inner angle, in company with the ophthalmic artery. The artery crosses 
the under surface of the nerve from its inner to its outer side. The optic nerve has 



8o 



APPLIED ANATOMY. 



as its covering a prolongation of the membranes of the brain. The dura mater 
when it reaches the foramen spHts and gives one layer to form the periosteum lining 
the orbit and the other to form a fibrous sheath of the nerve. This arrangement 
prevents pus, forming in the orbit, from passing through the optic foramen into 
the skull. The artcria centralis rctince enters the nerve on its under side and passes 
through its centre to the interior of the eye. The nerve itself is covered with a fine 
pial membrane and an arachnoid separating it from the dura, thus forming subdural 
and subarachnoid spaces. As these membranes and spaces are continuous with those 
of the brain, hemorrhage or serous efiusions occurring within the brain can thus find 
their way into the sheath of the nerve. 

As the nerve enters the eye, it is contracted and forms the optic disk or papilla. 



Cornea 



Greater arterial ring 
Iris 

Lesser arterial ring 

Ciliary process 



Canal of Schlemm 

^Corneal loop 



Perforating branch 

Conjunctival vessels 



Communication between 




Anterior ciliary vessels 



Sclera 
Episcleral vessels 



choroidal and optic vessels 
Central retinal vessels 



Vena vorticosa 

Supplying choroid 

Short posterior ciliary artery 

Long posterior ciliary artery 
Communicating twig 
Inner sheath vessels 
Outer sheath vessels 



Communication between optic 
and sheath vessels 



I 



Fig 94. — Diagram illustrating circulation of eyeball. (Leber.) 



It is readily seen with the ophthalmoscope as a round spot somewhat lighter in color 
than the surrounding eyeground. Coming from a depression or cup in the disk, 
called the poms opticus, are the retinal arteries and veins. A certain amount of 
cupping is normal, but if wide and deep, with overhanging edges over which the 
vessels can be seen to dip, it is indicative of glaucoma. 

Sometimes the papilla or disk is swollen, constituting an optic neuritis. 
In brain tumor this is frequently the case and is called choked disk, or ' 'stauung 
papilla''' so named because the circulation was thought to be interfered with owing 
to the intracerebral pressure being transmitted directly to the nerve. On the sub- 
sidence of a severe neuritis the nerve is left in a state of optic atrophy and blindness 
is the result. 




FIG. 95. 



NORMAL HUMAN FUNDUS OCULI, SHOWING OPTIC PAPILLA AND BLOOD VESSELS; ALSO THE MACULA UUTEA. 
DRAWN BY MR. LOUIS SCHMIDT. 



REGION OF THE EYE. 8i 

Muscles of the Orbit. — Six muscles are connected with the eyeball, 
four straight and two oblique. One muscle, the levator palpebrce, goes to the 
lid. The four recti muscles, superior, mferior, external, and hiternal, arise from a 
common tendinous origin, forming a ring or tube called the ligament of Zinn. 
This ligament or tube surrounds the optic foramen and is attached to the opposite 
side of the sphenoidal fissure. Through it run the optic nerve and ophthalmic artery, 
the third, fourth, and the nasal branch of the ophthalmic (fifth) nerve. 

The levator paipebrce and superior oblique arise to the inner side and above the 
optic foramen close to the origin of the other muscles. The superior oblique, after 
passing through its trochlea or pulley at the inner upper angle of the orbit, continues 
downward, backward, and outward between the superior rectus and the eye, to be 
inserted above the extremity of the inferior oblique. 



Ethmoidal cells 



Sphenoidal sinus 



Superior oblique 
muscle 



Superior rectus 
muscle 



Levator palpebrae 
superior muscle 




Superior ophthal- 
mic vein 



Lachrymal gland 



Fig. 96. — The roof of the orbit has been removed, showing the contents. 

The inferior oblique arises from the anterior edge of the orbit just to the outer 
side of the lachrymal groove. It passes outward, upward, and backward, over 
the external surface of the inferior rectus, to be inserted beneath the external rectus. 

The recti muscles insert into the sclera 5 to 7 mm. back from the cornea. In 
the operation for internal squint or strabismus, the internal rectus muscle is cut. 
It possesses the longest tendon of insertion, while the external possesses the shortest. 
The recti muscles pull the eyes toward their respective sides. The superior oblique 
turns the cornea down and out and rotates it inwardly. The inferior oblique turns 
the cornea up and slightly out and rotates the eye outward. A disarrangement of any 
of these muscles produces diplopia or double vision. 

Blood-Vessels of the Orbit. — The arteries of the orbit are derived from the 
ophthalmic artery, which breaks up into its various branches soon after it passes through 
the optic foramen. In enucleation of the eye there is practically no bleeding, 
because the arteria centralis is the only one divided, and it is small. In evisceration, 
or cleaning out of the contents of the orbit, the main trunk of the ophthalmic will 
not be cut unless the very apex is invaded. Hemorrhage is readily controlled by 
packing gauze into the orbital cavity. 

The veins of the orbit are the sjiperior and inferior ophthalmic. The former is 
much the larger and more important. It not only drains the upper portion of the 
orbit, but communicates directly with the angular branch of the facial, at the inner 
canthus of the eye. The infection of erysipelas sometimes travels along these veins 
directly from the nose, face, and scalp without, to the cavernous sinus and meninges 
6 



82 APPLIED ANATOMY. 

within, causing thrombosis and death. The inferior ophthalmic usually empties into 
the superior; its anastomoses at the anterior portion of the orbit with the veins of 
the face are much smaller and, therefore, not nearly so dangerous. 

Nerves of the Orbit. — The optic nerve is the nerve of sight. Interference 
with it produces blindness. The oculomotor or third nerve supplies all the muscles 
of the orbit except the external rectus and superior oblique. If paralyzed, the eye 
cannot be mo\'ed upward, inward, or to any extent downward. There will be ptosis 
of the upper lid from paralysis of the levator palpebr^e, and dilatation of the pupil and 
paralysis of the accommodation of the eye. If the sixth or abducens is paralyzed, the 
eye cannot be turned outward. If the fourth or pathetic is paralyzed, the superior 
oblique fails to act, and the double vision produced is w^orse when the patient looks 
down, because it is normally a depressor muscle. The lachrymal, frontal, and nasal 
bra7iches of the fifth are nerves of sensation, hence, in supra-orbital neuralgia and that 
affecting the nasal branch, pain is felt in the orbit at the inner angle of the eye and 
down the side of the nose. 

Retina. — On the interior of the eye, the expansion of the optic nerve forms the 
retina. The retina is divided into two lateral halves, each supplied by a corre- 
sponding half of the optic nerve. When the nerve reaches the optic chiasm it splits 
into two parts, one (internal fibres) going to the opposite side of the brain, and 
the other (external fibres) to the ganglia on the same side of the brain. Posterior 
to the chiasm, the nerve fibres form the optic tracts. The optic tracts, after leaving 
the chiasm, wind around the crura cerebri to the external geniculate bodies, thence 
they pass to the thalami and anterior corpora quadrigemina, and are continued back- 
ward into the cuneus lobule of the occipital lobe of the brain. 

It will thus be seen that a lesion affecting any portion of the optic pathway pos- 
terior to the chiasm will produce blindness of one-half of the retina of both eyes on 
the side of the injury; a right-sided lesion will produce blindness of the right half of 
both retinae, and a lesion on the left side, blindness of the left half of both eyes. This 
is called hemianopia. It is right lateral hemianopia if the right half of the visual fields 
is aflected, and left lateral if the left sides are allected. Affections of the optic nerve 
produce total blindness of that eye if the whole nerve is involved. If only a part is 
involved, then a tmilateral hc^nianopia may ensue. A bite77iporal hemiariopia may be 
caused by a tumor involving the anterior or middle portion of the chiasm. A binasal 
hemianopia requires a symmetrical lesion on the outer side of both optic nerves or 
tracts. A brain tumor located in the cuneus lobule would cause a lateral hemianopia of 
the same side, right or left, of both visual fields, hence sometimes called homonymous. 

The Eyelids and Conjunctiva. — The eyelids are composed of five layers, 
viz: {i) ski?i, (2) subcidaneons tissue, (3) orbicularis palpebrarum vuiscle, (4) 
tarsal cartilage with the contained Meibomian glands, (5) the conjunctiva. The 
juncture of the two lids at each end is called the inner and outer canthus. 

The skin of the lids is thin and the subcutaneous tissue loose and devoid of fat. 
For these reasons blood finds its way readily into the lids and shows plainly beneath the 
skin, constituting the familiar "black eye." The skin lends itself readily to plastic 
operations, as it is easily raised and the gap left can be readily closed. The blood 
supply of the lids is abundant, so that the flaps are well nourished and sloughing is 
not apt to occur. The folds in the skin run parallel to the edge of the lids, therefore 
the incisions should be made as much as possible in the same direction. The 
orbicularis palpebrarum muscle passes circularly over the lids and lies on the tarsal 
cartilage toward the edge of the lids and on the orbitotarsal ligament above. The so- 
called tarsal cartilage or plate is composed of dense connective tissue and contains no 
cartilage cells. It is attached externally by the external {lateral) palpebral ligament 
and internally by the internal {medial) palpebral ligament or tendo-oculi. This latter 
passes in front of the lachrymal sac. The tarsal plate is continued to the rim of the 
orbit by the orbitotarsal ligarnent or septiwi orbitale. The expansion of the levator 
palpebrae muscle ends in the upper edge of the tarsal cartilage and sends some fibres 
to the tissues immediately in front. The orbitotarsal ligament and tarsal cartilage 
prevent the fat of the orbit from protruding and also act as a barrier to the exit of pus. 

The tarsal cartilage contains the Meibomian glands. These can be seen in life, 
by everting the lid, as yellow streaks passing backward from the edge of the lids. 



REGION OF THE EYE. 



83 



Frequently these glands become obstructed and their mucus contents dilate the 
gland, forming a cyst known as chalazion. Suppuration may occur and pus instead 
of mucus is then contained within them. The wall of these cysts is formed by 
fiDrous tissue containing some of the epithelial cells of the glands; therefore, if an 
uninflamed cyst is simply opened and its contents expressed, it will soon reform. 
To prevent this recurrence, the lining membrane is curetted in order to remove the 
mucus-forming cells. The cyst may point and be opened either on the side of the 
skin or conjunctiva, preferably the latter. ' 

The openings of the Meibomian ducts are on the inner edge of the lids where 
the conjunctiva joins the skin. At the outer edge of the lids are the cilice or eye- 
lashes and connected with them are sebaceous and sweat glands. Infection of these 



Skin 
/ Subcutaneous tissue 

Orbicularis p ilpebrarum 
E-at 




superior 
Blood-vessel 

Henle's gland 



Duct in tarsal plate 



Artery of tarsal arch 



Meibomian duct 



Glands of Moll Cilia Ciliary muscle 

Fig. 97.— Vertical section of upper eyelid of child. X 15. (Piersol.) 



glands produces a small abscess called a stye. As they are on the outer edge of the 
lids they tend to discharge anteriorly and not toward the conjunctiva. 

The co?iju7ictiva covers the outer surface of the eye and the inner surface of 
the lids. The fold where it passes from one to the other is called the fornix. The 
tarsal or palpebral co7ijunctiva adheres closely to the tarsus and as it is transparent 
the Meibomian glands can readily be seen through it. The ocular or bulbar coft- 
junctiva is loosely adherent to the sclerotic coat and through it the conjunctival vessels, 
w'hich move with it, can be seen. The straight vessels going toward the cornea do 
not move when the coniunctiva is moved, because they lie deeper and are attached to 
the sclera. 

The Lachrymal Apparatus. — The lachrymal gland cor\s\^\.s of two portions: 
an orbital or superior portion and a palpebral or inferior portion. The orbital 



84 



APPLIED ANATOMY. 



portion is enclosed in a capsule and slung from the orbital margin by its suspensory- 
ligament. Beneath, it rests on the fascial expansion of the levator palpebree muscle. 
The palpebral portion is smaller than the orbital and is partially separated from it by 
the fascial expansion. It lies on the conjunctiva at the upper and outer portion of 
its fornix. The lachrymal gland opens by several fine ducts into the fornix of 
the conjunctiva. It is sometimes the seat of malignant tumors, but rarely of other 
troubles. The remaining lachrymal passages running from the eye to the nose are 
frequently the seat of inflammation, causing suppuration and obstruction. 

T\\Qpiinda lachryvialia in the top of each papilla lead into the canaliculi. These 
enter the lids perpendicular to their margin and turning at right angles join just 
before entering the upper end of the lachrymal sac. 

The lachrymal canal, embracing the sac and lachrymonasal duct, each about 
12 mm. in length, extends from just above the internal tarsal ligament or tendo oculi 
to the inferior meatus of the nose. The sac is strengthened posteriorly by the tensor 
tarsi or muscle of IIor?ier, which passes from the lachrymal bone to the pujicta, and 
by some fibres of the palpebral ligament. Anteriorly is the strong palpebral liga- 
ment. Below the palpebral ligament, the sac is comparatively weak and here it is 
that distention occurs and pus makes its exit. The duct lies in the lachrymal groove 
in the bone. It is narrower than the sac, being 3 to 4 mm. in width, and is the usual 



Lachrymal gland 




Lachrymal sac 

Lachrymonasal duct 



Inferior meatus 



'■y^/ ^ Inferior turbinate 
Fig. 98. — Lachrymal apparatus. 



seat of obstructions. To keep the passage open in case of stricture probes are 
passed. The direction of the duct is slightly outward and more markedly backward, 
being indicated approximately by a line drawn from the inner canthus to just behind 
the second premolar tooth. In probing the duct it is customary to first open the 
punctum in the lower lid — which is normally only one mm. in size — by slitting it and 
the caniculus with a Weber's canaliculus knife. The probe is directed horizontally 
until the sac is entered, which is recognized by the end of the probe striking the 
bone; it is then raised vertically and passed downward and backward and sometimes 
slightly outward until it can be seen in the inferior meatus of the nose about i cm. 
behind the anterior end of the inferior turbinated bone. 



THE EAR. 

The external auditory meatus, the tympanum., and the Eustachian tube are the 
remains of the first branchial cleft in the foetus. A failure of any portion of the cleft 
to close normally may leave small sinuses or depressions in the neighborhood of the 
ear. The external ear, also called the auricle or pinna, is composed mainly of a 
cartilaginous framework covered with thin skin; the lobe or lobide forms its lower 
part and is composed of dense connective tissue containing fat. The large concav- 
ity leading into the meatus is the concha. The skin of the ear is thin and moder- 



THE EAR. 



85 



ately firmly attached to the cartilage. The subcutaneous tissue contains little or 
no fat. Although well supplied with blood, the expo.sed condition of the blood-vessels 
renders the ear sensitive to cold, and frost-bites are common. Injuries and wounds 
of the cartilage are slow to heal, and if inflamed the cartilage becomes exceedingly 
sensitive. Swelling of the ear readily occurs from injury or erysipelas, and the tension 
is quite painful. 

Helix 
Fossa scaphoidea 



Crus antihelix superius 
Fossa triangularis 

Crus antihelix inferius 

Tragus 
Incisura intertragica 



Tuberculum superius 




Lobule 



Fig. gq. — The external ear. 

HcBmatoma aiiris, or effusions of blood, occur from traumatism, especially in the 
msane. While a h^ematoma may occur between the skin and perichondrium, on 
account of the firm binding of the skin to the cartilage it is usually between the 
perichondrium and cartilage. 

Angioma, or enlargement of the blood-vessels, not infrequently affects the 
external ear and may not only be disfiguring but, by showing a tendency to 




Chorda tympani 
Facial nerve 



'-■^, /""L— Internal ai'.ditorv meatus 



Semicircular canals 



Jugular vein 



Fig. icx) — Vertical section of the right ear. 



extension, may demand operation. The external ear derives its blood supply from 
the auricular branches of the temporal, internal maxillary, posterior auricular, and 
occipital arteries. As these are all branches of the external carotid, that artery is 
sometimes tied as a preliminary step to excising the angiomatous vessels. 

The External Meatus. — The external auditory meatus extends from the 
concha to the drumhead, and is about 2.5 cm. in length. A little less than one-half 



86 



APPLIED ANATOMY. 



of it is cartilaginous and a little over one-half bony. Viewed anteroposteriorly the 
canal has a slight curve with its convexity upward (Fig. loo). Viewed from above 
(Fig. loi ), it is seen first to pass backward and then forward, forming an angle before 
the bony wall is reached. In order to look into the ear and see the membrane it is 
necessary to straighten the canal, either by inserting a speculum or by pulling the 
auricle outward, upward, and backward. In children, upward traction is not so 
necessary as in the adult. The length of the canal is approximately the same in child- 
hood as in adults, but the bony part is still in a cartilaginous condition. The external 
opening is oval, while farther in the canal is more circular; hence the Gruber speculum, 
which is oval in shape, or the round speculum of Wilde can be used with almost 
equal satisfaction. The point of junction of the bony and cartilaginous parts is 
narrower than either end, and it is difficult to remove a foreign body which has 
passed this point. This is particularly true in children, the lumen of the external 
meatus being quite small and narrow while the tympanic membrane is nearly as 
large as in adults. 

The floor is longer than the roof, owing to the drum membrane inclining at an 
angle of 140 degrees. Cartilage forms the lower part of the canal, while the upper 



Carotid canal Eustachian tube 



Glenoid cavity 



Internal auditory meatus 



Membrana t>nipaiii 

Facial canal 




I 



Ceruminous glands 



Fig. ioi. — Right ear; horizontal transverse section 



part is completed by a fibrous membrane. Below and in front is the temporomaxillary 
joint,'' and just posterior is Xh^ glenoid lobe of the parotid gland. When the gland is 
inflamed and swollen it presses on the cartilaginous canal and produces pain ; and 
in cases of suppuration pus may discharge through the external meatus, gaining 
access to the canal through fissures in the cartilage called the fissures of Santorini. 
The cartilaginous portion of the meatus contains sweat-glands, sebaceous glands, and 
hair-follicles. There are only a few glands in the upper posterior portion of the bony 
meatus. On account of the location of the glands in the external portion of the canal, 
accumulations of wax, and abscesses, which result from infection of the glands, occur 
nearer to the surface than to the drum membrane. It is only when the canal begins to 
fill up that the wax pushes its way to the membrane. When furuncles occur, the lining 
membrane swells and by closing the canal prevents a view of the drum being ob- 
tained. Incising of furuncles of the auditory meatus is sometimes required. The 
site of the inflamed spot having been located, an incision can be made where 
indicated. If care is exercised, one is not likely to injure the drum membrane, 
because the abscess starts in one of the sebaceous glands, which are located in the 
external half of the meatus. The membrane lies 2.5 cm. from the surface, and the 
point of the knife should not be carried so deeply as that for fear of wounding it; 
there is no necessity of going so far inward. 



THE EAR. 87 

The meatus is supplied by the auriculotemporal braiich of the fifth and the 
auricular branch of the pneumogastric nerve. Irritation of the latter nerve is said 
to be the cause of feeling it in the throat when anything is put in the ear. 

Membrana Tympani. — The niembrana tympani is inclined downward and 
inward at an angle of about 140° to the upper wall (Troltsch) and 27° to the lower 
wall (Bezold) of the meatus ; it does not lie directly trans\erse, therefore in intro- 
ducing instruments into the ear the upper posterior part will be first encountered. 
The membrane is located 2.5 cm. (i in.) from the surface; this is to be borne in 
mind in puncturing the membrane or other operations. The membrane has three 
coats: an outer, continuous with the skin of the meatus; a fibrous or middle layer; 
and an internal or mucous layer, continuous with the lining of the tympanic cavity. 
The membrana tympani at birth is fastened at its circumference to the tympanic 
bone, which unites with the other portions of the temporal bone soon after birth. 
This ring of bone is incomplete at its upper portion for a distance equaling one-eighth 
of its circumference. This is called the notch of Rivi?ius. The fibrous layer does 
not extend across this notch, which is closed by the mucous membrane on the inside 
and by the skin layer of the membrane on its outer side. The part closing the notch 

.Membrana flaccida 



Short process of malleus 



Long handle of malleus 




Cone of light 
Fig. 102. — Outer surface of the tympanic membrane of the left ear. 

is called ShrapnelV s membrane or membrana flaccida. As it possesses no fibrous 
layer it is weaker than the membrane elsewhere and consequently is a favorite spot 
for pus to perforate in order to find exit from the middle ear. 

In examining the membrane by means of light thrown into the meatus through 
a speculum by the head mirror, one sees extending downward from its centre a small 
cone of light; any depression or bulging of the membrane will cause this cone of 
light to be altered in its position, or even cause it to disappear entirely. From the 
centre of the membrane upward extends a line which indicates the attachment of the 
long handle of the malleus, one of the bones of the middle ear. Stretching across 
the upper portion is the membrane of Shrapnell or membrana flaccida, so called on 
account of its not being so tense as the remaining portion. It is better supplied 
with blood-vessels than the other portion. 

The membrana tympani is of surgical interest on account of its being often dis- 
tended or perforated. A purulent discharge from the ear usually indicates disease 
of the middle ear or tympanum. If pus is coming from a furuncle of the meatus, the 
latter will be swollen and its source can readily be recognized. If it comes from 
outside of the meatus, as in cases of suppuration of the parotid gland, it will be recog- 
nized by an examination of the gland. There is no other source of pus but the 
middle ear and for it to gain exit it must perforate the membrane; this perforation 
can usually be seen with the speculum and head mirror, as can also bulging. 

In inflammation of the middle ear the effused serum or pus bulges the mem- 
brane outward. When this condition is accompanied, as it often is, by intense pain. 



88 APPLIED ANATOMY. 

paracentesis or puncture is resorted to. The preferable spot is the posterior lower 
quadrant. Paracentesis of the membrane should be done by beginning the incision a 
little above and behind the centre of the tympanic membrane, which slopes downward 
and forward at an angle of 140° to the upper wall, and cutting downward to its 
lower edge. One must avoid the long handle of the malleus, which extends directly 
upward from the centre of the membrane. In the upper posterior part are the incus 
and stapes, therefore this portion should be avoided; and running across the upper 
edge beneath the mucous membrane is the chorda tympani nerve. Division of this 
nerve is said to be a matter of not much account. Incision through the anterior part 
is not considered suitable for drainage. 

Perforations frequently occur through Shrapnell's membrane on account of its 
not having any fibrous layer; thus the pus does not go through the tympanic mem- 
brane proper. If perforation with a purulent discharge has existed for a long time 
granulations come through the opening, forming an aural polyp. To remove these 
a snare is used or caustic is applied. 

The Tympanum or Middle Ear. — The tympanic cavity is flat and narrow 
and is situated directly behind and also above the membrane. It has a floor and 
roof, and external and internal walls. It is divided into the portion behind the mem- 
brane and the portion above the membrane called the attic. The floor is narrower 
than the roof and is formed by the tympanic plate ^ which separates it from the jugular 

Aditus 
Facial nerve 

Oval window 
Canal for tensor 

ni muscle Carotid canal 




Euslachian tube 

Tympanic cavity 
Chorda tympani nerve 
Round window 

Fig. 103. — Right temporal bone : — The outer surface has been cut away, exposing the tympanic cavity, its inner wall, 

the mastoid antrum, Eustachian tube, etc. 

fossa containing the commencement of the internal jugular vein. The bone forming 
the floor is more difficult for pus to perforate than is that of the roof, so that exten- 
sion of middle-ear disease is less frequent through it. The 7-oof is comparatively 
thin and formed of cancellous tissue with a thin and weak outside compact layer; 
therefore it is a somewhat common site for pus to perforate and thereby obtain 
access to the middle fossa of the skull. The distance from the floor to the roof is 
approximately 15 mm. (| in.); half is behind the membrane and the rest forms 
the attic above. 

The external wall is formed below by the tympanic membrane and above by 
the bone. As the membrane is the weakest portion of the walls, collections of pus 
in the middle ear most often find a vent through it. Immediately behind the mem- 
brane are the lower portions of the ossicles, and above is the chorda tympani nerve. 

The internal wall is formed of bone and is from 2 to 4 mm. (yV to \ of an 
inch) behind the membrane. It is so close that in doing the operation of para- 
centesis care must be taken not to thrust the knife too deeply. In it are the oval 
and round windows (Fig. 103). 

There is no well-defined anterior or posterior wall. The anterior portion of the 
cavity is continued forward into the Eustachian tube; the canal for the tensor 
tympani muscle is immediately above it. Posteriorly the cavity of the attic is con- 
tinuous through the aditics with the mastoid antrum and the cells beyond. Posterior 



THE EAR. 



89 



to the opening of the Eustachian tube is an elevation on the internal wall called the 
promonto7'y, formed by one of the semicircular canals. Above the promontory is the 
fenestra ovalis, which lodges the stapes bone and communicates with the vestibule. 
Below and behind is the fenestra rotunda, closed by a membrane separating the 
cochlea from the middle ear. Above the fenestra ovalis is a ridge of bone marking 
the aqueduct of Fallopius, in which runs the facial nerve. 

The Eustachian tube passes from the anterior portion of the tympanic 
cavity downward, forward, and inward to the upper posterior portion of the pharynx 
about level with "the floor of the nose. It is about 3.5 cm. (approximately i^ in.) 
in length. The outer third, near the ear, is bony and the inner two-thirds are 
cartilaginous. The point of junction of the bony and cartilaginous portions is the 
narrowest portion of the tube and is called the isthmus. The tube is usually closed, 
but opens in swallowing, yawning, etc., thus admitting air to the tympanic cavity 
and mastoid cells. Catarrhal affections of the throat readily travel up the tube and 
set up an inflammation of the middle ear. Swelling of the lining of the tube follows 
and air no longer passes to the ear. To open the tube two methods are employed — 
that of Valsalva, and that of Politzer. The former consists in holding the nostrils and 
mouth shut and attempting to blow, when the action of the throat and palate muscles 
opens the tube and allows the air to enter. In the method of Politzer, the patient is 

Tegmen tympani 

Chorda tympani nerve 

Long handle of malleus 

Tensor tympani muscle 



Incus 



Tympanic membrane 




Eustachian tube 



Fig. 104. — View of the tympanic membrane and ossicles of the left ear from within. 



given a sip of water which he swallows on command. The nozzle of a rubber air-bag is 
placed in one nostril and the other held shut. As the patient swallows, the air-bag is 
compressed and the air enters the Eustachian tube. Sometimes this method is varied 
by asking the patient to say ' 'hock, ' ' thus causing the tube to open, when the air-bag is 
compressed. The calibre of the tube is sometimes so small that probes are passed 
up it to dilate it. Care is necessary to avoid introducing the probe too far or it will 
injure the ossicles of the ear. Pus will sometimes discharge through the tube. I 
have seen pus coming from the middle ear pass down the tube into the inferior 
meatus and be blown out the anterior nares. 

Lying in a separate canal immediately above and parallel with the Eustachian 
tube is the canal for the tensor tympani muscle. 

The attic is directly above the tympanic cavity and contains the greater part of 
the ossicles. Between the two along the inner wall runs a ridge of bone within which 
is the aquseductus Fallopii, containing the facial nerve. The roof of the attic is called 
the tegmen. It is a thin shell of bone, varying in thickness, and separates the cavity 
of the ear from the middle cerebral fossa above. Pus frequently eats its way through 
at this point and forms a subdural abscess, which by working its way backw-ard 
involves the lateral (transverse) sinus, causing thrombosis and general septic infection. 



APPLIED ANATOMY. 

The antrum is a little larger than the attic. The two cavities are~continuous 
through the aditus. The roof of the antrum is level with the roof of the attic and its 
floor is about level with the top of the membrane. It is thus seen to be directly 
above and posterior to it. 

Mastoid Cells. — The mastoid cells are continuous with the antrum and 
permeate the mastoid process down to its tip. The cells come so close to the surface 
that suppuration within them often bursts through and discharges behind the ear. 
The upper, inner, and lower portions of the bone are also sometimes perforated, which 
will be referred to later. 

Middle-ear Disease. — Suppuration from middle-ear disease is caused by an 
infective inflammation travelling up the Eustachian tube from the pharynx and nasal 
cavities. It may pass to the attic above and thence to the mastoid antrum and 
mastoid cells. Pus usually finds an exit by perforating the tympanic membrane and 
discharging through the external auditory meatus. As already stated, it may pa^s 
down the Eustachian tube to be blown out of the anterior nares. It has been known 
to pass down the canal for the tensor tympani muscle, and form a retropharyngeal 
abscess. As the pus reaches the pharynx behind the prevertebral fascia, it may 
extend laterally and appear externally behind the sternomastoid muscle. Having 
thus reached the base of the skull, the infection may involve the meninges and brain 
through the crevices in the bone. It is rare for it to perforate the bone below and 




Fig. 105. — Tenotomy of the tensor tympani tendon Fig. 106.- 

and separation of the incus from the stapes. 

Modified from Georges Laurens 



Removal of the incus by means of Ludwig's 
hook. 



■ 



anteriorly, and thus implicate the jugular vein and internal carotid artery. It may 
eat into the posterior wall and involve the facial nerve, which is covered by only a 
thin shell of bone, and produce facial paralysis, attack the internal ear through the 
fenestra ovalis and rotunda and pass through the internal meatus to the brain. If it 
extends upward and involves the attic and antrum, it may perforate the roof, or 
tegmen, and form a subdural abscess in the back part of the middle cerebral fossa, 
whence it travels a distance of about a centimetre to the lateral sinus, causing a 
thrombus to form, or it may produce an abscess of the temporosphenoidal lobe of 
the brain. The antrum and mastoid cells being continuous, the posterior and inner 
walls may be perforated, the pus thereby reaching the posterior cerebral fossa, 
again involving the lateral sinus, or producing a cerebellar abscess. If it perforates 
the mastoid process on its inner wall at the groove for the digastric muscle, the pus 
gains access to the back of the neck, forming what is known as Bczold' s abscess. 

Operations on the Middle Ear. — The operations on the middle ear, besides 
those involving the membrane, are done either for the removal of the remains of the 
membrane and ossicles, or else to clear out the antrum and mastoid cells and e\en, 
if necessary, examine the lateral sinus and jugular vein and explore the brain. They 
are done for suppurative affections, which may be either chronic, producing local 
symptoms, or acute, producing in addition constitutional disturbances and even 
general infection. Caries of the bones is a prominent condition in suppurative cases 



THE EAR. 



91 



of long standing, and the character of the operation is dependent on the extent to 
which the disease has progressed. 

In removal of the ossicles, the tympanic membrane is first separated around its 
edges. Then the tendon of the tensor tympani muscle is cut, and the incus disarticu- 
lated from the stapes. The latter is done by cutting with a bent knife across the 
axis of the stapes and not of the incus (see Fig. 105). The malleus is seized and 
drawn first down and then out, bringing the membrane with it, and afterwards the 
incus, which is detached by Ludwig's hook (see Fig. 106), is removed, and, if 
desired, the stapes. Granulations and pus are removed by the snare, forceps or 
curette. Care is to be taken to avoid, if possible, scraping away the thin shell of 
bone on the internal wall that covers the facial nerve. Any twitching of the 
muscles of the face indicates that the nerve is being irritated. The chorda 
tympani nerve, which passes on the inner side of the handle of the malleus and lies 
beneath the mucous membrane, is of necessity removed. No important symptoms 
follow its removal. 

Operations on the Antrum and Mastoid Cells. — In order to understand 
these operations, one must recall that the suprameatal crest is the ridge of bone forming 
the upper edge of the bony meatus, and a continuation backward of the posterior root 



Suprameatal tri- 
angle of Macewen 



Suprameatal spine 




Posterior root of zygoma 



Fig. 107. — Landmarks for operating to enter the mastoid antrum. 

of the zygoma. The upper and posterior edge of the meatus is formed by a thin, small 
shell or edge of bone running from the suprameatal crest downward and backward 
to the posterior wall; this is the suprameatal spine. Behind the suprameatal spine 
and between it and the posterior portion of the suprameatal crest is a depression, 
the suprameatal fossa. This suprameatal fossa is triangular in shape. The crest 
forms the upper side, the spine its anterior side, and the ridge of bone, running from 
the posterior portion of the crest to the lower portion of the spine, forms the posterior 
side. These three lines form the suprameatal triangle of Macewen. It is through 
this triangle that the antrum may be reached. The operation may be restricted to the 
antrum and tympanic cavity, or may include the whole or part of the mastoid cells, 
constituting the operation known as tympanomastoid exenteration. 

To reach the antrum a semicircular cut is made a centimetre back of the ear 
and the ear and membranous canal loosened and pushed forward. With a gouge 
chips of bone are removed from the suprameatal spine backward and from the crest 
downward as far as desired. This will extend considerably beyond the line marking 
the posterior boundary of Macewen' s triangle. The outer table of bone being 
removed, the cells are broken through parallel to the meatus and slightly upward, 



92 



APPLIED ANATOMY. 



for the lower level of the antrum corresponds to the upper edge of the meatus. 
It is hardly safe to penetrate deeper than 1.5 cm. (fin.) from the meatal spine 
inward, for fear of wounding the facial nerve. The mastoid antrum lies not only 
above and posterior to the membrane and tympanic cavity, but extends outward 
along the posterior and upper portion of the canal, and the facial nerve can be 



Mastoid antrum 

External auditory meatus 




Fig. ioS.- 



Mastoid cells 



-The mastoid antrum exposed by chiselling through the suprameatal triangle. The mastoid cells exposed 
by chiselling off the surface of ihe mastoid process. 



wounded only by passing across the antrum and attacking the bony covering of the 
Fallopian canal below and anteriorly. 

In doing a tympanomastoid exenteration, a more extensive procedure is 
performed. It consists in cleaning out the various communicating cavities and 
throwing them together, thus making their interior more accessible. The antrum is 

reached in one of two ways : either 
posteriorly, or anteriorly through 
the meatus. The posterior opera- 
tion, or that of Schwartze, Zaufal, 
and others, consists in removing 
the membranous lining of the bony 
meatus on its upper and posterior 
portions down to the tympanic 
membrane. The antrum is then 
entered as already described; the 
posterior bony wall of the meatus 
is chiselled away, giving access to 
the tympanum; the ridge of bone 
separating the roof of the bony 
meatus from the attic or epitym- 
panum is chiselled away (see Fig. 
109), and the membrane and os- 
sicles removed. This gives access 
to the tympanic cavity, epitym- 
panum, and antrum. As much of 
the mastoid cells as necessary is 
exposed by chiselling away their external covering of bone even down to the tip of 
the mastoid process. 

If the anterior operation of Stacke is performed, the membranous lining of the 
bony meatus is to be loosened and divided as close to the membrane as possible and 
drawn forward with the cartilaginous meatus. The drum membrane and as much of 
the ossicles as possible are then to be removed, and with a chisel or bent gouge the 




Fig. 109. — Chiselling away the spur of bone between the roof of the 
external auditory meatus and attic or epitympanum. 



THE EAR. 



93 



angle, or ridge of bone between the upper side of the bony meatus and epitympanum, 
or attic, cut away. The antrum is now entered by chiselHng away the upper posterior 
wall and the chiselling away of bone continued until the mastoid cells have been suffi- 
ciently exposed. The final result of these two methods is the same. The external 



Course of lateral 
(transverse) sinus 



Position 
mastoid antrum 



Suprameatal spine 




Anterior root of 
zygoma or emi- 
nentia articularis 



Posterior root 
of zygoma 



Mastoid process 



External auditory meatus 



Fig. 1 10. — Lateral view of the temporal bone, showing the relations of the lateral or transverse sinus and 

mastoid antrum. 



rneatus, tympanum, epitympanum, antrum, and mastoid cells are all thrown into one 
large cavity. Wounding of the facial nerve is to be avoided by first learning its course 
and then by sponging away the blood and cutting only the structures which are 
clearly visible. Tracing the facial nerve backward, it is seen (Fig. 103) entering 
the stylomastoid foramen, 
passing upward posterior 
to the tympanic cavity, 
and crossing at about its 
upper edge to pass above 
the oval window. Viewed 
in Fig. 101, it is seen that 
the Fallopian canal lies a 
trifle nearer to the external 
surface than does the tym- 
panic membrane, so that 
in making the opening into 
the antrum or in connect- 
ing the mastoid cells below 
the antrum with the tym- 
panic cavity, care should 
be taken to keep a little 
anterior or superficial to 
the membrane. 

Relations of the 
Brain and Lateral Si- 
nus. — In operating on the 
skull for middle-ear dis- 
ease, it is desirable to know- 
how to reach and how to avoid the brain and lateral sinus. The lower level of the 
brain in the region of the ear corresponds to a prolongation directly backward in a 
straight line of the posterior root of the zygoma. If one keeps below this line, he is 
not likely to open the brain case. If it is desired to explore the under surface of the 




Fig. 



Jugular foramen 



III.— Transverse section of the right side of the skull just behind the 
mastoid process ; looking forward. 



94 APPLIED ANATOMY. 

brain or dura directly over the middle-ear cavity, then one trephines above this line 
or suprameatal crest, the lower edge of the trephine opening- being .5 cm, above it. 
This will lead to the middle fossa of the skull, occupied by the temporosphenoidal 
lobe. The sharp upper and posterior edge of the petrous portion of the temporal 
bone gives attachment to the tentorium and separates the middle cerebral fossa in 
front from the posterior fossa, containing the cerebellum, behind. The point at which 
this ridge and tentorium reach the side of the skull is indicated by the point of cross- 
ing of a line drawn up from the tip of the mastoid process, midway between its anterior 
and posterior borders, and the line of the posterior root of the zygoma. The course 
of the lateral sinus is indicated by a curved line from above and to the right (about 
.5 to I cm.) of the external occipital protuberance to the upper posterior portion of 
the mastoid process and thence to its tip. The anterior edge of the lateral sinus 
reaches as far forward as a line drawn from the tip of the mastoid upward, midway 
between its anterior and posterior borders. The point at which it turns is where this 
mastoid line intersects the line of the zygoma. Its upper edge rises above this line 
approximately i cm. The sinus is I cm. in width. The distance of the sinus from 
the surface varies from .5 cm., or even less, at the top of the mastoid process to 1.5 
cm. at its tip. So uncertain is this that the only safe way to expose the sinus is to 
cut the bone of? with a mallet and gouge in thin chips parallel to the surface. The 
use of a trephine or other boring instrument is not to be advised. If the infection 
of the lateral sinus has extended to the jugular vein this latter must be reached by 
means of a separate incision in the neck. 

THE NOSE. 

Externally the nose forms a prbminent projection on the face, hence it is fre- 
quently injured and its construction should be studied in relation to those injuries. 
It forms a conspicuous portion of the features, hence deformities or disfigurements of 
it are very distressing, so that plastic operations are done for their relief. Internally, 
the nasal cavities are concerned in the sense of smell and form the passage-way to 
and from the lungs and the various accessory cavities for the air in respiration. It 
likewise serves as a receptacle for the tears as they come down the lachrymona^al 
duct. Interference with the flow of air by obstruction of the nasal chambers may 
cause affections of the pharynx, larynx, lungs, ears, or accessory sinuses — ethmoid, 
sphenoid, maxillary, and frontal. Catarrhal troubles may start in the nose and invade 
any of these parts. They may even extend up the Eustachian tube and cause deaf- 
ness; or up the lachrymonasal duct and cause trouble with the lachrymal canal or 
conjunctiva. A knowledge of the nose is essential to all those who wish to devote 
themselves especially to affections of the eye, ear, and throat, because the origin of 
the affections of these organs may be in the nasal chambers instead of the organ in 
which they are most manifest. 

The skin over the root of the nose is thin and lax. It is well supplied with 
blood by the frontal and nasal branches of the ophthalmic, and the angular branch 
of the facial arteries. In reconstructing a nose by means of a flap taken from the 
forehead, it is these branches that nourish it. The laxity of the skin allows the 
pedicle to be twisted around without interfering with the circulation. 

The skin over the tip and alae is thick and adherent to the cartilages. It pos- 
sesses a comparatively scanty blood supply, hence its liability to suffer from cold, and 
is a favorite site for ulcerations, as lupus, superficial epithelioma (rodent ulcer), etc. 
Sebaceous and sweat glands are abundant, and stiff hairs guard the inside of the nos- 
trils. These latter are not seldom the seat of small furuncles or boils, which are 
extremely painful. This is due to the tension caused by the congestion and swelling, 
which is restricted by the tissues being so firmly bound to the cartilages beneath. 

Nerves. — In addition to the olfactory nerve, the nose is supplied by the nasal, 
infratrochlear, and infra-orbital branches of the fifth nerve, hence the eyes water 
when the nose is injured. In certain cases of neuralgia affecting the ophthalmic 
division of the fifth nerve, pain is felt along the side of the nose. As the nasal 
nerve enters the skull from the orbit through the anterior ethmoidal foramen, it may 
be involved in disease of the ethmoidal sinuses. 



THE NOSE. 



95 



the 
the 



I 



Small alar , 
cartilage 



Lower lateral 
cartilage 



Nasal bone 



Septal 
'cartilage 



The nose proper consists of a bony and a cartilaginous portion. The bony portioyi 
is formed by the two nasal bones articulating with the frontal bone above, with each 
other in the median line, and with the nasal process of the superior maxilla on 
side. They are supported on the inside by the upper anterior portion of 
perpendicular plate of the ethmoid. 

This articulation does not extend n 

the whole length of the nasal bones 
to their tip, but only about half 
their length. 

The cartilaginous portion 
consists of four lateral cartilages, 
two on each side, upper and lower, 
and the triangular cartilage, or car- 
tilaginous septum on the inside. 

The external shape of the nose 
viewed in profile is composed of 
three portions: an upper of bone, 
a middle of cartilage — the upper 
lateral cartilages — and a lower, or 
tip, formed by the lower lateral car- 
tilages. The bridge of the nose is 
formed by bone; it slopes down- 
ward and forward and where it joins 
the upper lateral cartilage the line 
changes and slopes more downward, until the tip is reached, here the lower lateral 
cartilages bulge forward, forming a rounded and more or less projecting tip. 

Injuries to the Nose. — The bones and cartilages may be fractured or 
dislocated. This may involve either the outside structures or those forming the 
septum, and often both. The displacement depends on the character and direction 



Mesial crus of 
lower lateral 
cartilage 




-Bony and cartilaginous framework of nose, front 
aspect. (Piersol.) 




Fig. 113 — Fracture of the nose with deflection of the nasa! bone laterally. 

of the injury. It is either a displacement to one side, or the nose is crushed, 
producing a flattening of the bridge. If the displacement is lateral, whether by a 
dislocation or fracture, there is liable to be a deviation of the septum, because the 
bony and cartilaginous septum is connected with the bones and is apt to be carried 
with them to the side. If the displacement: is inward, not only are the nasal bones 
depressed, but the septum beneath may be either bent or fractured. The pushing 
of the septum toward the floor causes it tc buckle and bend or even break at the 



96 APPLIED ANATOMY. 

junction of the triangular cartilage with the perpendicular plate of the ethmoid and 
the vomer. In treating these fractures, the most efficient method is to grasp the 
septum with the flat blades of an Adams forceps (after cocainization; and lift 
the bones up or to one side as needed. In cases where it is not desired to use 
the forceps, the writer grasps the nose with a wet towel, makes traction to loosen 
the fragments, and then pushes them over into place. The triangular cartilage is 
frequently injured; with the displacement or loosening of the upper lateral cartilages 
a great amount of displacement may be caused, so that the nose instead of forming a 
straight line is bent to one side from the ends of the bones down to the tip. Injuries 
to the septum in childhood are probably the cause of a large number of the cases of 
deviation of the septum, spurs, etc., seen later in life. 

In fractures the mucous membrane is often torn, thus allowing air to enter the 
tissues at the site of fracture, producing emphysema. If such a patient blows the 
nose violently, the air may be forced under the skin of the face, around the eyes and 
up the forehead. 

Anterior Nares. — The nostrils or anterior nares in the white race are an 
elongated oval in shape and run in an anteroposterior direction, being separated from 
each other by the columna. They lie in a direction parallel with the floor of the nose. 




Fig. 114 — Fracture of the nose showing depression of the nasal bone. 

so that to examine the nasal fossae with a speculum the instrument is first introduced 
from below, then tilting the tip of the nose upward, the speculum is directed back- 
ward. To see the floor of the nose, it is necessary to raise the outer end of the 
speculum still higher, because the floor is below the bony edge. From the outer 
edge of the nostril the nasal cavities go upward and backward for a distance of .5 to 
I cm. This part, called the vestibule, is covered by skin, not mucous membrane. 
It bears stiff hairs — vibrissae. Inflammation of these hair-follicles and associated 
glands produces exceedingly painful pustules. It is here likewise that dried mucus 
collects and forms scabs, which stick to the hairs and are hard to remove. The 
attempt to remove them probably is the cause of infection and inflammation around 
the roots of the hairs. The vestibule leads to the ridge of bone or crest, which is 
directly posterior to the side of the nasal spine. This ridge of bone is on a higher 
level than the floor of the nose, and in order to view the latter the nostrils must be 
raised, by means of the speculum, above it (Fig. 115). 

View from the Anterior Nares. — In looking into the nose from in front, if the 
speculum is directed downward, the floor of the nose and the inferior meatus can 
be seen. On the inner side is the septum, on the outer the anterior end of the 



THE NOSE. 



97 




Vestibul 



Fig. 115. — Lateral view of the interior of the nose. 



inferior turbinated bone. Still higher is the middle meatus and the anterior end of the 
middle turbinated bone. The superior turbinated bone is not visible from the front, 
being in the upper posterior corner and hidden from sight by the middle turbinated. 
Sometimes in the upper portion of 
the nose, beneath the outer surface 
of the anterior extremity of the mid- 
dle turbinated bone, is seen a small 
cleft, the hiatus semilunaris, leading 
through the infundibulum into the 
frontal sinus. If the inferior turbi- 
nated has been shrunk with cocaine, 
and if the inferior meatus is roomy, 
one can see the posterior wall of the 
pharynx. This can be seen moving 
if the patient swallows, pronounces 
the letter "k," etc., (Fig. 116). 

Septum. — The nasal fosses are 
separated from each other by the sep- 
tum. This septum is formed (see 
Fig. 117) by the triangular cartilage 
in front, forming the cartilagifious sep- 
tum, and the perpendicular plate of 
the ethmoid and vomer behind, form- 
ing the bony septum. The posterior 
edge of the septum is formed solely 
by the edge of the vomer ; it can readily be seen with the rhinoscopic mirror. The 
affections of the septum are haematoma, ulcer and abscess, deviation to one side, 
spurs or outgrowths, and it may be the site of nasal hemorrhages. Hcematomas affect 

the cartilage of the septum and resemble 
those of the ear. They are usually due 
to traumatism and may become infected, 
forming a pus-like detritus or abscess. 
They can readily be recognized as a 
fluctuating swelling on the septum, one 
or both sides being affected. 

Deviations of the septum are bend- 
ings toward one side, and cause serious 
obstruction to breathing. They are prob- 
ably traumatic in origin and involve the 
cartilaginous portion. In operating for 
their correction, incisions are made 
through the cartilage and the projecting 
part pushed toward the median line. In 
some operations care is taken not to cut 
through the mucous membrane on both 
sides, as well as through the cartilage. 
This is done to avoid the formation of 
a permanent perforation of the septum, 
the presence of which may cause a very 
objectionable whistling sound when the 
patient breathes. As the mucous mem- 
brane covering the cartilage is thin, great 
care is necessary in dividing the cartilage 
to avoid wounding the side which it is de- 
sired to leave intact. The triangular cartilage is thin at its centre and thick at its edges. 
Spurs are usually outgrowths of bone or cartilage occurring in the line of 
juncture of the cartilage and vomer. On the floor of the nose the nasal crest may 
project quite perceptibly to one side; a cartilaginous projection may likewise occupy 
this site. As these spurs are found on the anterior edge of the vomer, they some- 
7 




Fig, 116. — Examining the anterior nares. Middle 
and inferior turbinates exposed to view. 



98 



APPLIED ANATOMY. 



times form a distinct ridge of bone running upward and backward. If the spur is 
short in extent, the farther posterior it is situated, the higher up it is on the septum. 
If marked, it is often accompanied by deviation of the septum and it may impinge 
on the lower turbinated bone opposite to it. These spurs are usually removed by 
sawing. A narrow-bladed saw is introduced with its back on the floor of the nose 
and the spur removed by sawing upward (Fig. ii8). 

Epistaxis or bleeding from the nose is said to occur in a large percentage of 
the cases from the septal branch of the sphenopalatine artery. This comes from the 
internal maxillary artery through the sphenopalatine foramen and passes downward 
and forward as the nasopalatine or artery of the septum. It anastomoses below with 
the anterior palatine branch of the descending palatine artery as it comes up from 
the roof of the mouth through \.\\e foramen of Stenson (incisor foramen). It also 
anastomoses with the inferior artery of the septum, a branch of the superior coronary. 
The bleeding point is to be sought for low down on the anterior portion of the 
cartilaginous septum near the anterior nares. Hemorrhage can be stopped by 
packing only the anterior or both the anterior and posterior nares. 



Perpendicular plate 
of ethmoid 



Triangular cartilage 



Vomer 




Fig. 117. — Septum of the nose. 

The arteries supplying the nasal cavities (Fig. 119; come from three directions : 
superior — the anterior and posterior ethmoidal, supplying the ethmoidal cells, the 
upper portion of the septum, the roof, and the outer wall anteriorly; inferior — the septal 
branch of the superior coronary artery and a branch of the descending palatine artery 
coming up through the incisor foramen; posterior — the sphenopalatine, giving its 
nasopalatine branch to the septum and also supplying branches to the ethmoidal 
cells, frontal and maxillary sinuses, and outer wall of nose, the Vidian and pterygo- 
palatine going to the posterior portion of the roof, and the desce^iding palatine giving 
branches to the posterior portion of the inferior meatus and posterior end of the 
inferior turbinated bone. 

The veins, like the arteries, are in three sets: the superior are formed by the 
anterior and posterior ethmoidal and some smaller veins passing upward through the 
foramen in the cribriform plate, ox foramen ccsczim, to the longitudinal sinus; the 
inferior communicate with the facial veins through the anterior nares; the posterior 
drain upward and backward through the sphenopalatine foramen into the pterygoid 
plexus. 

The lymphatics drain either anteriorly on the face or posteriorly through the 
deep lymphatics of the neck. Therefore, acrid secretions causing ulcerations of the 
anterior nares are liable to be accompanied by swelling of the submaxillary lymphatic 



THE NOSE. 



99 



nodes; while enlargement of the deep cervical lymphatics follows disease of the 
deeper nasal cavities. 

Nasal hvpertrophies are enlargements of the nasal mucous membrane. The 
mucous membrane of the nose or Schneiderian membrane has columnar ciliated cells 
on its surface and mucous cells beneath. It is prolonged into the various sinuses and 
cavities in connection with the nasal fossae. The membrane on the upper third of 
the septum, the upper portion of the middle turbinated, and the superior turbinated 
bone, contains the terminal filaments of the olfactory nerve. The membrane over 
the lower portion of the septum, over the lower edge of the middle, and the greater 
part of the inferior turbinated bones, contains a venous plexus which renders it 
erectile. On the slightest irritation this portion of the membrane will swell and 
obstruct the passage of air through the nostrils. Repeated swelling of the membrane 
of the septum produces thickenings of the septum, which if anterior may be seen 
through the nostrils, and if posterior by the rhinoscopic mirror. The membrane 




Spur 



Nasal crest 



over the inferior turbinated bones also becomes swollen and enlarged, constituting, if 
at the forward end, anterior hypertrophy, and if at the posterior extremity, posterior 
hypertrophy CFig. 120). They can be readily seen through the nasal speculum ante- 
riorly and by the rhinoscopic mirror posteriorly. They are treated by applications of 
acids, as chromic and trichloracetic, by the electrocautery, or are snared of! with the 
cold snare. Snaring is more often employed in reducing posterior hypertrophies, but 
both the anterior and posterior can be reached by an electrocautery point or a knife 
introduced through a speculum in the anterior nares. 

The Outer Wall. — The outer wall has on it the three turbinated bones — 
superior, middle, and inferior. The inferior is a separate bone, but the middle and 
superior are parts of the ethmoid bone (Figs. 121 and 122). 

The inferior meatus is between the inferior turbinated bone and the floor of 
the nose. The lachrymonasal duct enters this meatus just below the anterior end 
of the inferior turbinated bone. It j^erces the mucous membrane obliquely, being 
guarded by a fold called the valve of Hasner. The opening is not visible from the 
anterior nares and usually it is impossible to introduce a probe into it from them. 



lOO 



APPLIED ANATOMY. 



The middle meatus is between the middle and inferior turbinated bones. 
The mucous membrane covering the middle turbinated bone lies closer to it than 
does that of the inferior turbinated bone, so that it is comparatively rare that treat- 
ment is necessary to reduce it. 

Polypi usually have their origin in this meatus. Beneath the middle turbinated 
bone on the outer wall of the nose and only to be seen after removal of the bone, 



Anterior ethmoidal 



Posterior ethmoidal 



•Triangular cartilage — 



Septal branch of 
superior coronary 




Branch from the descending palatine 
Fig. 1 1 9. — .\rteries supplying the septum of the nose. 

there is, just anterior to its middle, a rounded eminence, the bulla etlunoidalis. In it 
is an opening for the middle ethmoidal cells. Immediately in front is a slit, the 
hiatus semihoiaris, into which open the maxillary sinus {antrum of Highmore) and 
the anterior ethmoidal cells. The hiatus is continued above as the infundibuhim, 
which enters the frontal sinus. The relation between the hiatus and the opening into 




Anterior nasal hypertrophy 



Posterior nasal hypertrophy 
Fig. 120. — View of anterior and posterior hypertrophies of the inferior turbinate. 

the maxillary sinus is such, in some cases, that it is possible for pus originating in 
the frontal sinus to discharge into the maxillary sinus. A knowledge of the relation 
of these parts is essential to those desirous of treating nasal diseases. 

The superior meatus is comparatively small and lies above the middle tur- 
binated bone. At the anterior edge of the superior turbinated bone is the opening 
tor the posterior ethmoidal cells. Sometimes there are two or three superior turbinals. 



THE NOSE. 



The spheno -ethmoidal XQ.CQS% is the cleft above the superior turbinated bone; into 
it opens the sphenoidal sinus. In order to examine and reach the openings of any 
of these sinuses, it is practically necessary to take away a part or all of the middle 
turbinated bone before they can be exposed to view. When this is done, they can 
be probed, washed out, drained, etc. (see Fig. 125). 

The frontal sinuses begin to develop about puberty. They occupy the lower 
anterior portion of the frontal bone. Their size and extent vary considerably. The 
usual size is from the nasion below to 
the upper edge of the superciliary ridges 
above and laterally from the median line 
to the supra-orbital notch. These limits 
may be exceeded considerably. They 
may go as far out as the middle of the 
upper edge of the orbit or even nearly 
to the temporal ridge. The anterior and 
posterior walls are separated a distance 
of 0.5 to I cm. The distance which they 
extend back over th-e orbit and upward 
also varies. The two sinuses are sepa- 
rated by a partition which is often to one 
side of the median line, so that it is apt 
to be encountered in opening the sinus 
through the forehead. The two cells 
often differ greatly in size and may be 
divided into various recesses by incom- 
plete septa. They have the infundib- 
ulum as their lower extremity, which 
passes into the hiatus semilunaris be- 
neath the middle turbinated bone and empties into the middle meatus. The frontal 
sinuses are frequently the seat of suppurative inflammation. This gives rise to 
pain and tenderness in the supra-orbital region and to a discharge from the cor- 
responding nostril. This discharge can be seen coming from beneath the anterior 
extremity of the middle turbinated bone. Owing to the proximity of the opening 
into the maxillary sinus, pus, coming down the hiatus from the frontal sinus, may 




Fig. 121. 



Outer wall of nose, showing the superior, mid- 
dle, and inferior turbinate bones. 



Probe in the lachrymo- 
nasal duct 



Hiatus semilunaris 



Opening of lachrymo- 
nasal duct 



Frontal sinus 

Anterior ethmoidal cell 
Middle ethmoidal cells 

Posterior ethmoidal cells 

Sphenoidal sinus 

Bulla ethmoidalis 
Superior turbinate 
Middle turbinate (anterior 
half removed) 




Opening into Inferior turbinate 

maxillary sinus 

Fig. 122. — View of outer wall of the nose and accessory cavities. 

pass mto the maxillary sinus, thus simulating disease of that cavity. In order to 
wash out the sinus, cocaine may be first applied to shrink the nasal membrane ; then 
sometimes one is able to pass a probe or irrigating tube into the hiatus semilunaris 
and thence up into the sinus. By removing the anterior extremity of the middle 
turbinated bone access to the hiatus semilunaris is more readily obtained. In cer- 
tain cases the frontal sinus is opened either through the supra-orbital region or 
entered through the roof of the orbit at its inner upper corner. The glabella is the 



I02 APPLIED ANATOMY. 

depression in ttie median line separating the superciliary ridges. In operating on 
the sinus from in front, the opening is to be made just to the outer side of the gla- 
bella in order to avoid the septum between the sinuses. In curetting the sinus, the 
thinness of the upper and posterior wall separating it from the brain, and of the 
lower wall or roof of the orbit, should be borne in mind, otherwise they are apt to be 
perforated. The sinus may be divided into recesses by partial septa projecting from 






Figs. 123 and 124. — Two views of the frontal sinus, showing variation in size in different individuals. The 
anterior wall has been cut away to expose the interior of the sinus. 

the sides. Drainage into the nose is obtained by passing an instrument from above 
downward through the anterior ethmoidal cells. In entering the sinus from below 
from the outside, the opening is made at the extreme anterior upper edge of the 
orbit, perforating the bone in a direction upward and inward. The opening into the 
sinus may be enlarged from within the nose by first inserting a probe to protect the 

brain and posterior wall and then chisel- 
ling or gnawing away the bone in front 
so that easy access is obtained through 
the nose for drainage, packing, etc. 

The ethmoidal sinuses or cells, 
three in number on each side, anterior, 
middle, and posterior, lie between the 
sphenoidal sinus posteriorly, and the 
lower extremity of the frontal sinus an- 
teriorly. The anterior cells lie in front 
of or just above the hiatus and open 
into it. The middle lie just posterior to 
the hiatus and open into the outer wall 
of the middle meatus, perforating the 
bulla ethmoidalis, which is a rounded 
projection on the outer wall beneath the 
middle turbinated bone. The posterior 
cells open still farther back beneath the 
superior turbinated bone in the superior 
meatus. In disease of these cells, pus 
from the middle and anterior ones will 
show in the middle meatus; from the 
posterior cells in the superior meatus. In this latter case it is to be detected pos- 
teriorly by means of the rhinoscopic mirror. Access to the cells is obtained by 
removing the middle turbinated bone. This is done by dividing it into two pieces 
by a transverse cut with forceps or scissors and then removing the two halves with 
a snare. By means of probes, curettes, and forceps, the openings into the cells may 




Fig. 125. — Probes introduced into the frontal, max- 
illary, and sphenoidal sinuses. The anterior portion of the 
middle turbinate has been removed. 



THE NOSE. 



103 



be discovered and enlarged as thought necessary. The region of the ethmoidal cells 
is that from which mucous polypi of the nose take their origin. They are a common 
accompaniment of suppuration of the accessory nasal cavities. They are usually 
removed by snares introduced through the anterior nares or more rarely by forceps. 
Caries affecting the anterior cells may extend into the orbit and the pus may form a 
fluctuating tumor above the inner canthus of the eye. Care should be taken not to 
mistake a meningocele for such a tumor. 

The sphenoidal sinuses are the most posterior, lying still farther back than 
the ethmoidal. They open into the spheno-ethmoidal recess above and posterior 
to the superior turbinated bone. Discharge from them goes into the pharynx and is to 
be seen with the rhinoscopic mirror. They can be reached by first removing the 
middle turbinated bone and then introducing a probe upward and backward from the 
anterior nares for a distance of 7. 5 cm. (3 in. ) in women and 8 cm. in men. They can 
be drained by cutting away their anterior wall with punch forceps introduced through 
the anterior nares. 

The maxillary sinus Hes beneath the orbit and to the outer side of the nasal 
fossee. It is the seat of tumors, often malignant, and inflammation; the latter 
accompanied by an accumulation of mucus or 
pus. The walls of the sinus are thin, so we 
find tumors bulging forward, causing a protrusion 
of the cheek. They press inward and obstruct 
the breathing through that side of the nose, or 
they push upward and cause protrusion of the 
eye by encroaching on the orbit. In operating 
on these tumors, the superior maxilla is usually 
removed ; the lines of the cuts through the bones 
being shown in Fig. 64. In prying the bone 
down posteriorly, it may not be torn entirely away 
from the pterygoid processes and some plates of 
bone may be left attached. This should be borne 
in mind in operating for malignant growths. The 
sphenoidal cells are behind the upper posterior 
portion of the maxillary sinus, therefore in oper- 
ating on Meckel's ganglion, if too much force is 
used in breaking through the posterior wall of 
the antrum, the instrument may pass across the 
sphenomaxillary fossa, a distance of about 3 mm. , 
and open the sphenoidal sinus. 

The infra-orbital nerve is usually separated 
from the cavity of the sinus by a thin shell of 
bone. At the upper anterior portion of the sinus 
there may be a small cell between the bony canal 

in which the nerve runs and the bony floor of the orbit. The superior dental nerves 
reach the upper teeth usually by going through minute canals in the bone, but some- 
times, particularly the middle set supplying the bicuspid teeth, may run directly beneath 
the mucous membrane, and thus be irritated by troubles originating within the sinus. 

■ The inflammatory and infectious diseases of the sinus originate either by extension 
from the nose or the teeth. The sinus opens into the nose by a slit-like opening into the 
middle meatus about its middle,posterior to the hiatus semilunaris and 2. 5 cm. above the 
floor of the nose. When the opening is close to the hiatus, liquids may run into it from 
the hiatus. The bone beneath the hiatus and opening almost down to the floor of the 
nose is quite thin, so that the sinus can readily be drained by thrusting a trocar and can- 
nula through the outer wall of the nose into the sinus just below the hiatus semilunaris. 
The sinus is also opened from the front through the canine fossa to the outer side of 
the canine tooth. This opening affords direct access to the cavity, but is some distance 
above the floor, thus it does not drain the cavity completely. The roots of the upper 
teeth project into the antrum forming elevations, usually covered by a thin plate of bone. 
This is particularly the case of the first and second molars. Disease of the roots of these 
teeth frequently infects the antrum and drainage is often made through their sockets. 

*See article by H. H. Stark on Sudden Blindness Due to Suppuration of the Accessory 
Nasal Sinuses, J. A. M. A., Oct. 30, 1915. 




Fig. 126.- 



-Side view of the maxillary and 
frontal sinuses. 



I04 



APPLIED ANATOMY. 



THE MOUTH AND THROAT. 

The lips are formed mainly by the orbicularis oris muscle with its subdivisions 
and the accessory facial muscles (buccinator, levator and depressor anguli oris, 
levator labii superioris, levator labii superioris akeque nasi, the zygomaticus major 
and minor, and the depressor labii inferioris). The orbicularis oris is attached tc 
the superior maxilla in the incisor fossa above the second incisor tooth and also 
above to the septum. In the lower lip it is attached to the mandible beneath the 
second incisor tooth. The lips contain, beside muscular tissue, some areolar tissue, 
arteries, veins, and lymphatics. The muscular fibres are inserted into the skin. The 
mucous membrane lining the lips has lying beneath it some mucous glands. They 
sometimes become enlarged and form small, shot-like, cystic tumors containing mucus. 

Affections of the Lips. — The lips are affected by wounds, angioma or blood 
tumor, cancer {epithelioma), and clefts {harelip). Wounds of the lip when properly 
approximated heal readily on account of the free blood supply. The arteries sup- 



Auricularis superior 



Occipitalis 
Auricularis anterior 

Auricularis posterior 



Zygomaticus major 
Zygomaticus minor' 

Levator anguli oris 

Levator labii superioris 

Buccinator 

Risorius 




Frontalis 

Gorrugator supercilii 
Orbicularis palpebrarum 
Orbital part of same muscle 
Pyramidalis nasi 

— Lev. labii sup. alaeque nasi 
— Compressor narium 

^ [Oilatores naris 

~~" Depressor aloe nasi 

Orbicularis oris 

Depressor anguli oris 
Depressor labii inferioris 
Levator nienti 



Platysma 



Fig. 127. — Superficial dissection, showing the muscles of the head and face. (Piersol.) 



plying the lips are the superior and inferior coronary branches of the facial. They 
are given ofT about opposite the angle of the mouth and pierce the muscle to run 
beneath the mucous membrane about midway betwen the edge of the lip and its 
attachment to the gums or nearer the free border of the lip. Therefore, in operating 
on the lip, the artery should be looked for in this situation and not toward the skin 
surface or in the substance of the lip. The superior coronary sends a branch to the 
nasal septum, called the inferior artery of the septum. In the sulcus between the 
lower lip and chin lies the inferior labial artery. The bleeding from this branch is 
not so free as that from the coronary arteries, because the anastomosis across the 
median line is not so marked. 

Angioma. — The blood-vessels, mainly the veins, of the lips sometimes become 
enlarged, forming a large protrusion. This may be noticed at or soon after birth 
as a dusky blue, slightly swollen spot on the lip. As the child grows the swelling 
enlarges. Sometimes it enlarges rapidly and operation is necessary to check its 
growth; otherwise it may involve a large portion of the face and prove incurable. It 
is composed of dilated veins with thin walls and large lumen. It does not pulsate 
and disappears under pressure, only to return when this is removed. It is treated 
by excision. The thin skin is dissected off and the growth cut away from the tissues 
beneath, the bleeding being controlled by pressure, haemostats, and ligatures. In 



THE MOUTH AND THROAT. 105 

the case figured, the facial vein, as it crossed the mandible, and the transverse facial 
vein were obliterated by means of acupressure pins passed beneath them, and the 
growth was excised. 

Cancer or epithelioma of the lip almost always affects the lower and not the 
upper lip. The disease extends through the lymphatics. These pass down and out 








Fig. 128. — Angioma involving the right half of the upper 
lip in a child. (Personal sketch.) 



Fig. 129. — Single harelip. 



from the lips to the submaxillary lymph-nodes and then to the nodes along the 
great vessels of the neck. It is in these regions that lymphatic infection is usually 
seen. The middle of the lower lip is drained into a node in the submental region in 
front of the submaxillary nodes. 
This also is sometimes involved. 
In operating for cancerous 
growths it is advisable to re- 
move all nodes from both the 
submental and submaxillary tri- 
angles. 

Cleft or harelip is so named 
from its resemblance to the lip 
of a hare. It is a deformity due 
to lack of development, in which 
the lip is cleft or split from the 
mouth up into the nostril, and 
sometimes even back through 
the hard and the soft palate. 
When the cleft is slight, it may 
not reach the nostril. It is 
practically always to one side of 
the middle, going toward one 
nostril. Sometimes the harelip 
is double, involving both sides. 
In such cases the bone between 
the two clefts may protrude. In 
the development of the face, the 
frontonasal process comes down 
from above to form the middle 
portion of the nose, upper lip. 




Fig. 130. — Double harelip, showing the projecting premaxilla. 



and upper jaw. It forms a bone known as the premaxilla and bears the incisor teeth. 
From the sides spring the nasal and maxillary processes. These join together as one 
process and grow toward the premaxilla. If this process fails to reach the premaxillary 



io6 



APPLIED ANATOMY. 



bone, a cleft is left constituting harelip. If both processes fail to reach the premaxilla, 
a double harelip is formed; the cleft may extend through the hard and the soft palate— 




Frontonasal process 

Medial nasal process 



Nasal pit 

Lateral nasal process 



Lachrymonasal furrow 



Maxillary process 
First visceral arch 

Mandibular process 
First visceral furrow 
Second visceral arch 
Second visceral furrow 
Third visceral arch 



Pig. 131. — Frontal view of human foetus about four weeks old. (After His.) 

the cleft palate may alone be present as seen in Fig. 139 (see page 112). In operating foi 
harelip, the two sides of the cleft are freshened and sewed together, thus closing the cleft. 




Fig. 132. — Paralysis of depressor labii inferioris from section of the lower filament of the facial nerve. (McDowd.> 

Paralysis of the lips is due to interference with the functions of the seventh nerve. 
The muscles of the face and lip are supplied by the seventh or facial nerve. This is 
frequently paralyzed, for owing to its tortuous passage through the temporal bone in 
the canal of Fallopius it is injured in fractures of the base of the skull and becomes 



THE MOUTH AND THROAT. 



107 



affected from middle ear disease or neuritis. When paralyzed, the muscles of the 
lips, both upper and lower, on the affected side, droop. The drooping of the lower lip 
may allow the saliva to run out of the mouth. It is also impossible for the patient 
to pucker his mouth, as in whistling. If the lesion of the facial nerve is inside the 
skull and not in the Fallopian canal, t\\e great petrosal nerve and some of the palatal 
muscles will be paralyzed, the voice will be altered and swallowing interfered with. 

The depressor labii inferioris instead of receiving its nerve supply from the supra- 
mandibular branch of the facial, frequently is supplied by the inframandibular branch; 
pressure or injury of this branch in enlargements of or operations on the submandib- 
ular lymph-nodes has produced paralysis of the muscle with a peculiar alteration of 
the facial expression, well shown (see Fig. 132) by a case of Dr. McDowd (Anrials 0/ 
Surgery, July, 1905). 

Mouth. — Surface Anatomy. — In looking into the mouth, one sees the tongue 
below and the roof above, surrounded in front and on the sides by the teeth. On each 
side are the inner surfaces of the cheeks and posteriorly are seen the uvula, the 




Hard palate 

Junction of the hard 
and soft palates 

Soft palate 

Uvula 

Anterior pillar of fauces 

Posterior pillar of fauces 

Tonsil 



Fig. 133. — Interior of the mouth. 

arches of the palate, and the pharynx. On the mucous membrane of the cheek, 
opposite the second upper molar tooth, is a small papilla in the top of which opens 
the duct of the parotid gland. A small probe can be inserted into it and passed 
outward and backward toward the gland. 

Tongue. — The tongue is covered with a mucous membrane which is modified 
skin; therefore it is subject to the same diseases as the skin. It is covered with 
papillae of three kinds — the filiform, ftaigiform, and circnnivallate. The filiform 
are the smallest and most numerous and form a sort of ground-work in which the 
others are imbedded. The fungiform are larger and fewer in number and are scattered 
on the dorsum, sides, and tip of the tongue among the filiform. The circum vallate, 
seven to twelve in number, form a V-shaped row at the base of the tongue. In the 
eruptive fevers, particularly scarlet fever, the tongue gets very red and the papillae 
become enlarged, forming what is known as the strawberry or raspberry tongue. 
Just beyond the apex of the circumvallate papillae in the median line is the foramen 
ccscuni. It is sometimes patulous for a short distance and is the upper extremity of 
the remains of the thyroglossal duct. 



io8 



APPLIED ANATOMY. 



On the posterior portion of the tongue behind the circunivallate papillse, on 
each side of the median Hne, is a mass of adenoid tissue which forms what is known 
as the lingual tonsil. It sometimes becomes hypertrophied and is then cut off with 
a specially curved tonsillotome just as is done with enlarged faucial tonsils. Run- 
ning from the base of the tongue to the epiglottis are three folds, called the 7nedian 
and lateral glosso-epiglottic folds. 

In the middle of the dorsum of the tongue is a furrow; this is caused by the 
septum binding the middle of the tongue down and allowing the muscles to rise on 
each side. 

On turning the tip of the tongue up (Fig. 135), a fold of membrane, Xho. frcsnum, 
is seen extending from the under surface to the floor of the mouth beneath. In new- 
born children, this fraenum appears sometimes to be too short, hence the name tongue- 
tie. In cutting it, the split end of a grooved director is placed over the fraenum 




Posterior nares; 
turbinated bone 



Fossa of Rosenmiiller 
Eustachian tube 

Faucial tonsil 

Foramen caecum 
Lingual tonsil 

Cuneiform tubercle (Wrisberg) 

Comiculate tubercle 
(Santorini) 

Sinus pyriformis 
Cricoid cartilage 



Fig. 134. — View of pharynx, looking forward; posterior wall removed, showing the posterior nares, base of tongue, 

and opening of the larynx. 

and the tongue pushed back. This makes the freenum tense and it can readily be 
snipped with the scissors. Care should be taken not to cut too deeply, or the ranine 
artery may be cut and cause troublesome bleeding. Running across the floor of the 
mouth, between the teeth and tongue, parallel to the alveolus, is the sublingnal ridge, 
formed by the sublingual gland. This gland lies on the mylohyoid muscle beneath 
and the lower jaw in front. On each side of the fraenum on the sublingual ridge is a 
papilla into which the duct of the submaxillary gland, \VJiar ton s duct, opens. Open- 
ing into Wharton's duct, or by a separate duct into the same papilla, is the duct of 
the sublingual gland, called the duct of Rivinus or Bartholin. The superficial por- 
tion of the gland opens on the sublingual ridge to the outer side of the papilla by a 
number of small ducts, called the ducts of IValthcr. 

Ranula is the name given to a cyst occurring in connection with the salivary 
glands. Such cysts involving the parotid gland are quite rare, so that the term 



THE MOUTH AND THROAT. 



109 



is usually restricted to those of the submaxillary and sublingual glands. The 
mylohyoid muscle forms the floor of the mouth and these cysts lie on it beneath 
the tongue and between the tongue and the gums (Fig. 136). If the cyst is large it 
causes a protrusion or swelling beneath the jaw. The bulk of the submaxillary gland 
lies on the side of the mylohyoid muscle nearest the skin; only a small portion of it 




Fraenum 



Sublingual ridge 

Orifice of 
sublingual and 
submaxillary ducts 



Fig. 135. — Under surface of tongue and floor of mouth. 



winds around the posterior edge of the muscle. Therefore, cysts involving the sub- 
stance of the gland would show in the submaxillary region of one side. If, how^ever, 
the duct were obstructed (as by a calculus) it would form a cyst, which would bulge 
into the mouth beneath the tongue and be called a ranula. The sublingual gland is 
usually the starting point of these cysts, and it will be seen that as they enlarge they 








Cyst 



Fig, 136. — Sublingual cyst (ranula). (From a photograph by Dr. Ashhurst.) 

push the ranine artery with the tongue backward and are only covered by the mucous 
membrane. On this account there is little or no danger in operating on them. 
They are either dissected out or the front wall of the cyst cut away and the interior 
cauterized or packed with gauze to promote the formation of granulations. The 
jaw-bone is in front of them and the mylohyoid muscle beneath. Posteriorly lies the 
duct of the submaxillary gland and the ranine artery. 



APPLIED ANATOMY. 

Mucous cysts can occur from the mucous glands of the mouth and 
There is a ghmd on the under side of the tip of the tongue, usually larger than the 
others, called the anterior lingual gland or gland of Nuhn. As a rule, these mucous 
cysts are small and are felt as hard rounded bodies beneath the mucous membrane. 
Derrrioid cysts occur in connection with the tongue but very rarely. 

Carcinoma of the tongue is a moderately frequent disease and as the tongue is 
covered by modified skin, the cancer is of epithelial type. It begins on the surface 
of the tongue either by a change in the epithelial covering or else in fissures or ulcers 
at its edges. 

The lymphatics of the tongue pass to the submaxillary nodes beneath the jaw 
and thence to the deep cervical nodes along the great vessels or directly to the latter 
without passing through the submaxillary nodes. If the disease exists for any length 
of time, these are the nodes that become infected. They are only to be reached by 
an incision in the neck. 

The arteries of the tongue are the lingnal a?id its branches, the hyoid, the 
dorsalis linguce, sublingical, and ranine. In removing the tongue, the lingual 




Anterior lingual gland 



— Ranine artery 



Lingual nerve 



Orifice of submaxillary 
and sublingual glands 

- Sublingual gland 



Fig. 137.— Under surface of the tongue, mucous membrane removed. 

artery on the side to be removed is sometimes ligated in the neck ; this cuts of^ the 
blood supply to that side and there is practically no bleeding. There is very little 
anastomosis between the vessels of the two sides of the tongue. The arteries run 
lengthwise through the tongue, so that in glossitis or inflammatory swelli)ig of the 
tongue, incisions should always be made longitudinally into it. 

The ligation of the lingual artery will be found described in the section on the 
neck. As the lingual artery passes above the hyoid bone, it gives off its flrst branch, 
the hyoid. It is quite small and goes above the hyoid bone superficial to the hyo- 
glossus muscle. The lingual then goes beneath the hyoglossus muscle and near the 
posterior edge gives of? its second branch or dorsalis linguce. 

In excision, the tongue is usually cut through on the distal side of the dorsalis 
linguae artery. When this is the case, the bleeding which occurs from the branches 
of the dorsalis linguae is not marked because it is not a large artery. 

In order to draw the tongue out, it must be loosened posteriorly by cutting the 
anterior pillars of the fauces and palatoglossus muscle, and anteriorly at the fraenum 
by cutting the geniohyoglossus muscle. By drawing the tongue up, the ranine artery 



THE MOUTH AND THROAT. in 

is drawn out of the way and there will be only slight bleeding from small branches 
of the sublingual, which comes from the main trunk at the anterior edge of the hyo- 
glossus muscle. From this point forward to the tip, the lingual artery is called the 
ranine. The tongue having been loosened and pulled out, Mr. Jacobson makes a 
transverse cut through the mucous membrane behind the growth and then, by push- 
ing the tissues aside with a blunt instrument, exposes the hngual nerve and artery 
lying together beneath the mucous membrane. The artery is then tied and the 
growth removed. 

In order to secure any bleeding points after the tongue has been cut away, the 
floor of the mouth can be raised and pushed forward by the fingers beneath the chin. 



Styloglossus muscle 
Hyoglossus muscle 




Lingual nerve 



Submaxillary 
ganglion 



Geniohyoglossus muscle 
Ranine artery 

Ranine vein 



Sublingual gland 

Submaxillary duct 

Fig. 138. — The cheek has been split, the tongue drawn forward, and the mucous membrane removed from 
its under surface, exposing the ranine artery and vein, the lingual and hypoglossal nerves, the sublingual gland, 
the submaxillary ganglion, and the duct of the submaxillary gland. 

This brings the stump into view and within reach. If lymphatic nodes are to be 
removed, they must be sought for by an additional incision on the outside beneath 
the jaw. 

The roof of the mouth is formed by the hard palate and the soft palate ; the 
former comprising about three-fourths and the latter one-fourth. The hard or bony 
palate is composed in its anterior two-thirds of the palatal processes of the superior 
maxillary bones, and in its posterior third of the palatal bones. In the median line 
close to the incisor tooth, in the dried skull, is the anterior or nasopalatine foranieii. 
This is subdivided into four foramina, two lateral and two anteroposterior. The 
former, called the foramina of Stenson, transmit the terminal branches of the de- 
scending palatine arteries; of the latter, c-A}\QA\\'\^fo7'amina of Scarpa, the anterior one 
transmits the left nasopalatine nerve, and the posterior one the right nasopalatine 
nerve. The soft tissues of the roof of the mouth are thicker than they appear to be, 
so that when they are raised, as in operating for cleft palate, they form quite a thick 
layer. Infection of the roof of the mouth when it occurs is usually by extension from 
neighboring diseased teeth, abscesses being sometimes produced. 

The blood supply of the roof is of importance in relation to the operation for cleft 
palate {staphylorrhaphy) (Fig. 139). The blood comes anteriorly from the nasopala- 
tine arteries and posteriorly from the descending palatine arteries, which come down 



APPLIED ANATOMY. 

through the pterygopalatine canal from the internal maxillary artery and make their 
appearance on the hard palate at the posterior palatine foramen. This foramen is on 
the roof of the mouth opposite the last molar tooth and 0.5 cm. to the inner side and 
in front of the hamular process (Fig. 140). This hamular process can be felt just pos- 




Opening of the 
pharyngeal pouch 



Fig. 139. — Cleft palate, showing the opening of the pharyngeal pouch on the posterior wall. 

terior and to the inner side of the last molar tooth. If, in operating for cleft palate, the 
tissues are loosened from the bone too close to the hamular process, this artery may be 
torn near its exit from the foramen, in which case the bleeding is very free. To control 
it, the canal can be plugged with a slip of gauze. In detaching the soft palate from 




Posterior or descending 
palatine artery 



Hamular process 
Tensor palati muscle 



Fig. 140. — Roof of the mouth, mucous membrane removed. 

the posterior edge of the hard palate, it should be remembered that this attachment 
is quite strong. Not only are the muscles of the soft palate themselves attached to 
the bone, but the pharyngeal aponeurosis which lies under the mucous membrane on 
the posterior or upper surface of the soft palate is also attached to the bone. 

Palatal Arches. — Farther back in the mouth, one sees the anterior and pos- 
terior arches of the palate or pillars of the fauces with the uvula. The anterior 



THE MOUTH AND THROAT. 



113 



pillar runs from the soft palate to the tongue and is formed by the palatoglossus 
muscle. The posterior pillar runs from the soft palate downward to the sides of the 
pharynx and is formed by \\\it palatopharyngeus muscle. In front of these arches and 



'Pharyngeal tonsil 




Fossa of Rosenmuller 
Eustachian tube 

Supratonsillar fossa 

Pterygomandibular fold 
Plica triangularis 

Anterior pillar 
Faucial tonsil 
Posterior pillar 

Epiglottis 



Fig. 141. — Lateral view of the faucial tonsil and pharyngeal region 



running from the roof of the mouth opposite the posterior edge of the last molar tooth 
downward to the posterior edge of the alveolar process of the lower jaw is an elevation 
of the mucous membrane which shows the line of junction of the hard and soft palates. 




Fig. 142. — Diagram illustrating the blood supply of the faucial tonsil. 

Faucial Tonsils. — Between the pillars of the fauces lie t\\it faucial tonsils. 
They are limited above by the sulcus, called the supratonsillar fossa, formed by the 
approximation of the pillars and a fold of mucous membrane, called the plica trian- 
gularis (His), running downward from the anterior pillar and often blending with 
8 



114 



APPLIED ANATOMY. 



the tonsil. Below they extend a variable distance, necessitating depression of the 
tongue with a spatula in order to make their lower limit accessible. They lie opposite 
the angles of the jaw on the pharyngeal aponeurosis (p. ii6) with the superior con- 
strictor muscle and bucco-pharyngeal fascia outside. A knowledge of their structure 
is essential to the proper treatment of their diseases. The tonsils are oval in shape and 
when normal in size project but little beyond the pillars of the fauces. They are about 
2. 5 cm. long by i cm. wide and consist of about a dozen recesses or crypts formed 
by the folding inward of the mucous membrane. From these crypts follicles extend. 
The walls of the crypts contain adenoid tissue as well as mucous glands. The tonsil 
is held together by connective tissue which is contmuous with its capsule and the 
submucous fibrous tissue of the pharynx. This capsule rests on and blends more or 
less completely with the fibres of the pharyngeal aponeurosis. On this account while 
an enlarged tonsil can at times, usually in young children, be shelled out of its bed, 
especially its upper portion, at others it is necessary to dissect or cut it out by means 
of a knife, scissors, tonsillotome, or snare. 

The blood-vessels supplying the tonsil are five in number. They are : the 




Fig. 143. — Point of puncture for tonsillar abscess. " If an imaRinary horizontal line is drawn across the 
base of the uvula, and another vertically along the anterior faucial pillar, they will intersect at a jwint overlying 
the supratonsillar fossa. Just externaJ to this is utte best point for opening a quinsy." — St. Clair Thomson, M.D., 
Brii. M. J., March 25, 1905, p. 645. 

ascending pharyngeal branch of the external carotid, the ascending palatine and 
tonsillar branches of the facial, the tonsillar branch of the dorsalis linguce, and the 
desce?iding palatine branch of the internal maxillary. Ordinarily, these branches are 
small, but sometimes some of them are large and may cause troublesome hemorrhage. 
In inflammation of the tonsils, these vessels of course are larger than usual. 

The tonsils are subject to inflammation and tumors. Tumors are rare; they 
grow inward and obstruct breathing and swallowing. Attempts are made to remove 
them either by scraping, cutting, snaring, or burning them with the electrocautery 
from the mouth; or they are sometimes removed through an external incision through 
the neck. This latter is a very severe procedure on account of the depth of the 
tonsil and the number of important structures which overlie it. 

Tonsillitis or quinsy is an inflammation of the tonsils which leads to the for- 
mation of an abscess. In mild cases the crypts or lacunae are affected, forming a 
follicular or lacunar tonsillitis. In this form epithelium and inflammatory matter are 
poured into the follicles and distend them, often showing as white plugs protruding 
from the mouth of the crypt. In its treatment, in addition to local applications, 
surgeons enlarge the openings into the crypts with a small knife and scoop the con- 
tents out with a sharp spoon. In severe cases, the whole substance of the tonsil 
and even the connective tissue around it are involved in the inflammation, forming 
a parenchyftiatous tonsillitis. It frequently proceeds to the formation of pus. When 
this forms in the substance of the tonsil it may break into a follicle and discharge into 
the throat. An abscess of the tonsil may become quite large, bulging toward the 



THE MOUTH AND THROAT. 



IIS 



median line, and on breaking may cause suffocation by passage of the pus into the 
larynx. If, as is usually the case, the pus involves the tissue around the tonsil, form- 
ing a peritonsillar abscess, it pushes upward behind the anterior pillar into the supra- 
tonsillar fossa and bulges forward, stretching the pillar over it. To evacuate this pus 
an incision should be made directly anteroposteriorly, with the flat side of the blade 
parallel with the edge of the pillar, or a slender pair of haemostatic forceps may be used. 
A centimetre and a quarter (}^ in.) is deep enough usually to plunge the knife; the 
point should not be pointed outwardly but directly backward. The incision should 
be just above the upper and lateral edge of the anterior pillar (Fig. 143). Some 
small vessels may bleed, but this will either stop spontaneously or may be controlled 
by packing. The ascending pharyngeal artery lies beneath the tonsil. The tonsil 
lies on the pharyngeal aponeurosis and the superior constrictor muscle, while the as- 



Anterior pillar 



Tonsil 



Posterior pillar 




Styloglossus 

Stylopharyngeus 

Stylohyoid 

Internal carotid artery 

Internal jugular vein 

Digastric 

Stemomastoid 



Longus colli 



Rectus capitis anticus major 



Pig. 144. — Transverse frozen section passing through the faucial tonsil and showing its relation to the internal 

carotid artery. 

cending pharyngeal artery and external carotid lie outside of them, so that both 
structures would have to be cut before the vessels would be wounded. The internal 
carotid artery lies still deeper (2 to 2.5 cm.) behind and external to the tonsil. It is 
usually well out of harm's way unless dilated (see page 123, Fig. 156), but the pus may 
burrow into it and cause fatal hemorrhage. Sometimes pus may burrow through the 
constrictor muscle and enter the tissues of the neck. In severe tonsillitis the deep 
lymphatics beneath the angle of the jaw become enlarged. 

Hypertrophy of the tonsils is common and is treated by removing them entirely or 
level with the palatal arches. An instrument called the tonsillotome is used, or it 
is done with a knife or scissors or snare. Fatal bleeding has followed this oper- 
ation. The blood supply to the tonsil has already been given. If the bleeding is so 
free as to threaten the life of a patient, the external carotid artery should be ligated 
as all the vessels supplying the tonsil are derived from it. 



ii6 



APPLIED ANATOMY. 



Enucleation is performed by grasping the tonsil with toothed forceps, drawing it 
out, and cutting it loose with knife, scissors, or snare from its attachments to the pil- 
lars and aponeurosis beneath. Sometimes after loosening its attachments above it is 
torn loose or shelled out, from above downward, by the finger or a blunt instrument. 
On account of the attachment of the capsule to the pharyngeal aponeurosis the tonsil 
cannot always readily be ' ' shelled out ' ' and portions may remain and require to be 
removed with the forceps and scissors or tonsillar punch. The incision through the 
mucous membrane should begin posterior to the free edge of the plica triangularis 
— not anterior. The tonsil grows more adherent to the deep structures as the child 
increases in age. It is a disagreeable and bloody procedure and is often done under 
a general anaesthetic. 

Retropharyngeal abscess may arise from any one of three causes, — cervical 
caries, suppuration of lymphatic nodes, or extension of pus from the middle ear 
through the canal for the tensor tympani muscle. The pharyngeal aponeurosis lies 
under the mucous membrane and between it and the constrictor muscle. It is thick 
above and fades away below. It fills up the gap above between the superior constric- 
tor and the base of the skull and is attached to the pharyngeal spine on the under surface 
of the basilar process. It is lined with the mucous membrane and covered by the 
constrictor muscles. Over all is the buccophary7igcaI fascia, a thin layer continu- 
ous forward over the buccinator muscle and separated from the prevertebral fascia 




Fig. 145. — Cervical caries with retropharyngeal abscess opening just posterior to the stemomastoid muscle. 

by very loose connective tissue. The space between these two layers of fascia 
is known as the retropharyiigeal space and pus 'can follow it downward behind the 
pharynx and oesophagus into the posterior mediastinum. Retropharyngeal abscesses 
occur external to the pharyngeal aponeurosis and bulge into the throat. On account 
of the looseness of this aponeurosis and its lack of firm attachments, these abscesses 
may not bulge forward as a distinct circumscribed swelling, as abscesses do elsewhere, 
but are more apt to gravitate downward and hang in a loose bag-like manner opposite 
the base of the tongue. They are not easily felt, being so soft, and to see them prop- 
erly the tongue should be held down with a tongue depressor. In looking for their 
origin, a careful examination of the spine should be made to detect the possible 
existence of spinal caries or Pott 's disease, and the ear should be examined for suppur- 
ative otitis media. The lymph-nodes, which often give rise to these abscesses, espe- 
cially in children under two years of age, are one or two lying on the anterior surface 
of the vertebral column between it and the pharyngeal aponeurosis and constrictor 
muscles. In evacuating these abscesses the safest way is to place the child on its 
back with the head hanging; the pus then gravitates toward the roof of the pharynx. 
The tongue is held out of the way with a tongue depressor and the abscess can be 
well seen and incised. Raising the body causes the pus to flow from the mouth. 



THE MOUTH AND THROAT. 



117 



The pus may not only point in the mouth but can work its way laterally. In 
such a case it may pass out behind the sheath of the great vessels and make its 
appearance, as I have seen it, behind the posterior edge of the sternomastoid muscle. 
If a tumor is present in this situation, the pus may be evacuated by an incision at 
this point and the abscess drained there instead of making an opening through the 
pharynx. This, of course, tends to guard against infection from the mouth. 

Lingual Nerve. — The lingual nerve or gustatory branch of the fifth can be 
readily exposed in the mouth. On looking into the mouth, a fold can be seen going 
up and back just behind the last molar tooth. This is formed by ihe pteryg07na7tdib- 
ular ligament, running from the tip of the internal pterygoid plate to the posterior 
extremity of the mylohyoid ridge and joining the buccinator with the superior con- 




Mandibular (inferior 
dental) nerve 

Mandibular (inferior 
dental) artery 

Mandibular spine 
(Spix) 

Lingual nerve 



Submaxillary gland 



Submaxillary duct 
Sublingual gland 



Fig. 146. — View of mandibular and lingual nerves from within. 

strictor muscles. An incision made just internal to this fold, below and behind the 
last molar tooth, will lead one down to the lingual nerve close to the bone. 

The mandibular nerve is also reached through an incision running from the 
last upper to the last lower molar tooth. The finger is introduced and the spine of 
Spix felt at the inferior dental foramen. The nerve and artery enter the mandible at 
this point, the artery being below and posterior. The operation of Paravicini on this 
nerve through the mouth is unsatisfactory on account of the lack of proper exposure. 
It is better to attack the nerve from the outside as detailed on page 60. 



PHARYNX. 

The pharynx is the common air and food tract that lies behind the nose, mouth, 
and larynx. It extends from the base of the skull above to the oesophagus below. 
Its lower end is at the cricoid cartilage, which is opposite the sixth cervical vertebra. 
In passing an instrument directly backward through the nose, one strikes the base of 
the skull or interval between the basilar process and the atlas. In looking into the 
throat through the mouth, one is level with the body of the second vertebra. If, by 
means of a hook, the soft palate is raised or pushed aside and the head tilted slightly 
backward one sees the anterior tubercle of the atlas. The rounded projection can 



ii8 



APPLIED ANATOMY. 



readily be felt. The pharynx has seven openings into it, viz. : the two posterior nares, 
the two Eustachian tubes, the mouth, the larynx, and the cesophagus. 

Posterior Nares or Choanse. — These can readily be seen by means of the rhino- 
scopic mirror. They are separated by the posterior edge of the bony septum, the 
vomer bone. They are 2.5 cm. (i in.) long and 1.25 cm. wide, hence are of sufifi- 
cient size to allow a well lubricated little finger to pass into them from the anterior 
nares. The tip of an index linger can be inserted through the mouth below, hence 
the entire length of the lower meatus of the nose and upper surface of the soft palate 
can be palpated. 

Projecting from each lateral wall toward the septum are the rounded posterior 
ends of the middle and inferior turbinated bones. Sometimes, high up, the posterior 
end of the superior turbinate can be seen. The posterior end of the inferior turbi- 
nate is frequently enlarged by a swelling of its membrane, forming a posterior hirbi- 

Septum 

Pharyngeal tonsil 
Eustachian tube 

Fossa of Rosenmuller 

— First cervical vertebra 

Lingual tonsil 

Anterior pillar ' ' "^"' ' -^^^^^ ^ —Uvula 

_ Second cervical vertebra 

Faucial tonsil- 
Posterior pillar- 
Third cervical vertebra 



Fourth cervical vertebra 

Cuneiform tubercle 
(Wrisberg) 

Fifth cervical vertebra 

Arytenoid cartilage 

Sixth cervical vertebra 

(Esophagus 

Cricoid cartilage 

Seventh cervical vertebra 



Epiglottis 

Hyoid bone 

False vocal cord 

Thyroid cartilage. 

Ventricle 

True vocal cord. 



Cricoid cartilage 
Trachea 




Fig. 147. — Lateral view of pharynx and larynx. 

nate hypertrophy. Not only does the mucous membrane of the inferior turbinate 
bones become enlarged, but that on the septum likewise. This constitutes hypertrophy 
or thickeniyig of the septum. A polypus may project from the nasal cavities back- 
ward into the throat. I removed a very large one by pushing it with the finger into 
the pharynx and then dragging it out of the mouth. 

The posterior nares are quite a distance anterior to the edge of the soft palate, 
hence it is extremely difificult to make appHcations by way of the mouth. A much 
easier way is to make them through a tube introduced into the nose, or even, as 
when the electrocautery is used, without a protecting tube. 

Eustachian Tube. — On each side, at a point about opposite the inferior turbi- 
nals, are the orifices of the Eustachian tubes with \\\q. fossa of Rosenmiiller above. 
The Eustachian tube runs from the upper portion of die pharynx to the middle 
ear, opening just behind the tympanic membrane, on the anterior wall. It is about 



THE MOUT] 



119 



4 cm. long, 2.5 cm. being cartilaginous (pharyngeal portion) and 1.5 cm. being 
bony. At the junction of the bony and cartilaginous portions the lumen is slightly 
diminished, forming the isthmus. The tube runs upward, backward, and outward. 

The mucous membrane of the throat is continuous with that lining the tube and 
tympanum, therefore inflammation of the pharynx travels up the tube and affects the 
middle ear. This is the manner in which earache or inflammation and suppuration 




Fig. 148 — Rhmoscopic mirror in position. A view 
can be obtained of the vault of the pharynx and poste- 
ror nares. 



Fig. 149- — Palpation of the posterior nares and phar- 
yngeal tonsil. 



of the middle ear is produced. This also explains why impairment of hearing so 
often accompanies or follows sore throat. When the tube is in a healthy condition, 
the air finds free access to the ear, in swallowing, sneezing, etc. This is readily 
demonstrated by closing the nostrils and swallowing, when the pressure of air out- 
side the ear drum will be distinctly felt. - When inflammation affects the lining mem- 

'Vault of pharynx 
^/Superior turbinate 



Septum 

Middle turbinate 

Mouth of Eustachian tube 

Inferior turbinate 



Fig. ISO. — View of posterior nares in the pharyngeal mirror. 

brane it swells and blocks up the tube and prevents the free access of air to the ear. 
If the swelling is not too great, air can be forced from the throat to the ear by three 
different means. The distention of the middle ear by air is called inflating it. The 
method of Valsalva consists in holding the nostrils and mouth shut and blowing. 
If the air enters the middle ear, the tympanic membranes will be felt to bulge 
outward. The method of Politzer is to have the patient hold a small quantity of 




I20 



APPLIED ANATOMY. 



water in the mouth. The nozzle of a rubber bag^ is introduced into one nostril, 
closing both nostrils with the fingers and thumb of the unengaged hand. On telling 
the patient to swallow, the bag is compressed and the air enters the Eustachian tube. 
As the patient swallows, the tensor palati muscle opens the mouth of the tube and 
as the bag is compressed the air rushes up the tube. Sometimes the vapors of ether, 
chloroform, etc., are used. The third method is by the Eustachian catheter. 

The Eustachian catheter is a small, hard rubber or silver tube, slightly bent 
at the extremity and long enough to reach from the anterior nares in front to the 
posterior wall of the pharynx. The end of the catheter having been inserted into 




iuperior turbinate 



Sphenoidal sinus 



Middle turbinate 
Inferior turbinate 

Pharyngeal tonsil 
Fossa of Rosenmiiller 
Eustachian lube 

Atlas 

Odontoid process 
of axis 



Body of axis 



Third cervical vertebra 



Fig. isi. — Anteroposterior frozen section, showing a lateral view of the phar>'nx and the relation of the various 

neighboring structures. 

the mouth of the Eustachian tube, air is blown in with the Politzer air-bag. By 
means of a rubber tube going from the patient's ear to the surgeon's ear, the air can 
be heard entering the middle ear. 

Introducing the Eustachian Catheter. — In introducing the Eustachian catheter, 
the tip of the nose is to be tilted upward until the anterior nares are raised to the 
level of the floor of the nose. The tip of the catheter is then passed first upward 
(Fig. 152), then along the floor until it is felt to pass beyond the soft palate and strike 
the posterior wall of the pharynx (Fig. 153). It is usually advised to enter the 



THE MOUTH AND THROAT. 



121 



catheter in a vertical position and then change to a horizontal one as soon as the beak 
passes over the elevation which marks the separation of the vestibule of the nose from 
the interior. If this method is used, care should be taken to keep the tip of the catheter 
on the floor of the nose and not pass it up in the region of the middle turbinate bone. 

There are three ways of introducing the beak of the catheter into the mouth of 
the tube after it is felt touching the posterior pharyngeal wall. The first is to with- 
draw the beak about 2 cm. away from the 
wall of the pharynx and then turn it upward 
and outward, pushing it a trifle onward. 
The second way is to turn the beak directly 
outward and draw it forward, when it can 
be felt passing over the cartilaginous open- 
ing of the tube. The third way is to turn 
the beak inward and draw it forward until 
it catches behind the septum. This is op- 
posite the anterior edge of the mouth of 
the tube. The beak is then rotated down- 
ward and then upward and outward into 
the tube. 

Liquids and sprays are sometimes in- 
jected into the ear through the catheter; 
bougies are also passed into the tube in the 
same manner as the catheter or, if flexible 
bougies are used, they are passed through 
the catheter. As the tip of the bougie 
passes into the bony portion of the canal, 
the constriction of the isthmus can be felt 
2.5 cm. up from its mouth. The bougie 
should not be passed farther than 3 cm. 
into the tube, otherwise, if the tympanum is entered, the ossicles are apt to be injured. 

Openings of the Mouth, Larynx, and CEsophagus.^The opening of the 
mouth into the pharynx is sometimes narrowed from cicatricial contractions, resulting 




Introducing the Eustachian catheter, first 
step. 




Fig. 153.- 



-Introducing the Eustachian catheter, 
second step. 



Fig. 154. — Introducing the Eustachian catheter, 
third step. 



from ulcerative processes due to syphilis, caustics, etc. There is rarely obstruction 
downward, so that these patients can usually swallow, but the cicatrices contract the 
opening upward, and the soft palate, its arches, and the walls of the pharynx may be 
all bound together in one cicatricial mass, preventing, as I have seen, all respiration 
through the nose. This condition is an exceedingly difficult one to remedy, as the 
contraction tends to recur even after the most radical operations. 

The opening into the larynx is more accessible than is often supposed. On 
drawing the tongue well forward, the tip of the epiglottis can be seen. If a long 



132 



APPLIED ANATOMY. 



straight tongue depressor is used, Kirstein has shown that in many patients the 
arytenoid cartilages and even a portion of the vocal cords can be seen. The open- 
ing into the larynx can readily be felt by a finger introduced into the mouth. In cases 
of suffocation from a foreign body, as a piece of meat, it is usually lodged at this 
point, part of the foreign body being in the larynx and part in the pharynx. It can 
readily be dislodged by the finger, as I have done in impaction of meat, the result of 
vomiting in ether narcosis. The forefinger should be thrust its full length into the 
mouth and throat and swept from side to side. The obstructing body can usually 
be brushed aside and brought up in front of the finger into the mouth. 

The opening of the esophagus is in a line with the long axis of the pharynx ; it 
is at its lower end. The opening of the larynx, on the contrary, is more on its 
anterior wall. It is for this reason that when an oesophageal tube is introduced, either 
through the mouth or through the nose, it goes down into the oesophagus and does 
not enter the larynx. The oesophagus is narrowest at this point. 

The pharyngeal tonsil stretches across the posterior wall and roof of the 
pharynx from the opening of one Eustachian tube to that of the other. It is also 

'Pharyngeal tonsi' 



Fossa of Rosenmiiller 
Eustachian tube 

Supratonsillar fossa 

Pterygomandibular fold 
Plica triangularis 

Anterior pillar 
Faucial tonsil 
Posterior pillar 

Epiglottis 




Fig. 15 s. — Lateral view of the pharyngeal region. 



known as LuschkcC s tonsil. It is composed of lymphoid tissue, and when enlarged 
constitutes the disease known as adenoids. It is not true secreting gland tissue, 
though it contains some mucous glands. It hangs from the vault of the pharynx in a 
more or less lobulated mass and when large, in children, obstructs nasal respira- 
tion. Mouth-breathing results, the child is apt to snore and make queer sounds 
when sleeping, and the habit of keeping the mouth open causes a peculiar expres- 
sion of the face almost pathognomonic of the affection. The blood supply at times 
is abundant. When adenoids are present, their removal is usually undertaken. 
This is done by introducing an instrument either through the nose or through the 
mouth and scraping them off. A curette is used for this purpose. That known as 
'Gottstein's consists of an oval-shaped ring set at right angles to a long shaft. It is 
introduced through the mouth and up behind the soft palate. It is then pushed 
against the vault of the pharynx and posterior wall and drawn downward cutting 
and scraping the adenoid tissue away. A much smaller ring curette set on a long, 
delicate, but stiff handle may be used through the nose for the same purpose. In using 
the latter instrument, it is common to use an anaesthetic and operate with the head 
in a hanging position. Free bleeding may occur from this operation. To control it, 
injections of ice water or a strong alum solution may be tried or gauze may be 
packed behind the soft palate or pushed in from the anterior nares. A folded pad of 



THE MOUTH AND THROAT. 



123 



gauze may be attached to the thread of a Bellocq cannula and the pad introduced 
as is done in plugging the posterior nares. A curved forceps with cutting blades 
is also used to remove this growth. 

Fossa of Rosenmiiller. — This is the depression abo\e and behind the open- 
ings of the Eustachian tubes. The walls of the pharynx are weakest at this point 
owing to the superior constrictor muscle not coming so high up. Hernia of the 
mucous membrane sometimes occurs here. When the beak of the Eustachian cath- 
eter fails to enter the mouth of the tube it usually enters this fossa. 

The internal carotid artery runs up the neck outside of the pharynx and 
opposite the space between the posterior arches of the palate and the posterior wall 
of the pharynx. It is from i to 2 cm. behind and to the outer side of the tonsils. 
It is separated from the cavity of the throat by its own proper sheath, by the thin 
buccopharyngeal fascia covering the constrictor muscles, by the constrictor muscles, 
the pharyngeal aponeurosis, and the mucous membrane. As the tonsils lie between 
the pillars of the fauces, in opening a tonsillar abscess the knife is not carried either 




^0^' 



Fig. 156.— Transverse dissection of the neck. The posterior wall of the pharynx has been removed and the vessels 
exposed. The internal carotids are seen to be abnormally tortuous, with a tendency to bulge into the pharynx. 

behind or through the posterior pillar of the fauces. It is practically impossible to 
wound a normal internal carotid artery. In old people the internal carotid sometimes 
becomes lengthened and tortuous in the same manner as do the temporal arteries. In 
such cases the artery may form a pulsating swelling behind and projecting farther 
inward than the edge of the posterior pillar. This I have once seen. It may be 
mistaken for a true aneurism, as it pulsates and the pulsation is readily stopped by 
pressure on the common carotid on the outside of the neck. If, however, the possi- 
Ijility of this condition is borne in mind, the diagnosis can readily be made. The 
pulsating swelling can readily be seen and felt with the finger just behind the posterior 
pillar of the fauces. 

The mucous membrane of the nasopharynx is ciliated columnar; that of the 
lower portion is squamous. It contains racemose mucous glands and follicles or crypts 
surrounded by lymphoid tissue. It is well supplied with blood-vessels. It is fre- 
quently affected by inflammation or pharyngitis. When the follicles are markedly 
involved they can be seen studded over the posterior wall of the pharynx. This 
constitutes a follicular pharyngitis. Not infrequently some ulceration may be 
present, forming an idceraiive pharyngitis. Infection attacks it, as in diphtheritic 
pharyngitis. Should pus or pharyngeal abscess form around the pharynx, arising 
from an infection from the oral cavity, the pus occupies the retropharyngeal space 



124 



APPLIED ANATOMY. 



between the buccopharyngeal fascia and prevertebral fascia. Its spread upward is 
limited by the skull; laterally it is limited by the sheath of the carotid vessels; hence 
it passes downward behind the oesophagus and may enter the posterior mediastinum. 
Foreign bodies may become lodged at the lower end of the pharynx and at the 
beginning of the oesophagus. As this is about 15 cm. (6 in.) from the teeth, it is 
beyond the reach of the finger. Luckily, this is below the opening of the larynx and 
the need for immediate relief is not so urgent. 



THE LARYNX. 

The larynx extends from the top of the epiglottis to the lower edge of the 
cricoid cartilage. It is composed of the three large cartilages — epiglottis, thvroid, 
and cricoid — and three pairs of small ones — the arytefioids, the cornicidcc laryngis 
or cartilages of Santoriui, and the cuneiform or cartilages of Wrisberg. 

The position of the larynx in relation to the spine varies according to age. In 
the infant it lies opposite the second, third, and fourth cervical vertebrae; in the adult 



Epiglottis 




Greater horn of hyoid bone 



Lesser horn 

Body of hyoid bone 

Superior comu 

Opening for superior laryngeal 

nerve 



Thyrohyoid membrane 
— ^Thyroid cartilage 



Inferior comu 
Cricothyroid membrane 
Cricoid cartilage 

Trachea 



Fig. 157. — Anterior view of hyoid bone and larynx. 

it lies opposite the fourth, fifth, and sixth. The larynx being loosely attached \'aries 
in relation to the vertebrae according to the position of the head, so that the anterior 
portion of the cricoid cartilage may be opposite the seventh cervical vertebra in some 
positions. 

Epiglottis. — Usually the tip of the epiglottis lies lower than the dorsum of the 
tongue, so that looking into the mouth it is not seen; it may, however, be brought 
into view by depressing the base of the tongue and drawing it forward with a long 
tongue depressor. As the epiglottis rises above the level of the hyoid bone, a cut- 
throat wound passing above that bone may cut its tip entirely off. In viewing the 
epiglottis from above downward it is seen to project somewhat backward in its middle. 
This is visible in the laryngoscopic mirror and is called the cushion of the epiglottis. 

Running forward fiom the epiglottis to the base and the sides of the tongue are 
three folds of mucous membrane, one median and two lateral, called the glosso- 
epiglottic folds. These form four fossae; those on each side of the median line are 
called the vallecidce. In these fossae foreign bodies, such as fish-bones, etc., may 
become lodged. They are readily seen by the laryngoscopic mirror. 



THE MOUTH AND THROAT. 125 

The thyrohyoid membrane passes between the hyoid bone above and the 
thyroid cartilage below ; crossing it is the hyoid branch of the superior thyroid artery. 
It is a quite small vessel, of little clinical importance, and ordinarily does not reach 
the median line. 

The posterior edge of this membrane, running from the superior cornu of the 
thyroid cartilage to the hyoid bone, is called the thyrohyoid ligament. This liga- 
ment has a small cartilaginous nodule in it, the cartilago triticea. Piercing the 
membrane on its side are the internal branches of the superior laryngeal nerve 
and the superior laryngeal vessels. The external branch of the superior laryngeal 
nerve supplies the cricothyroid muscle, while the internal is the ner\e of sensation 
of the larynx. 

Pharyngotoniy. — Sometimes, in order to remove foreign bodies in the larynx or 
oesophagus, an opening is made^;hrough the membrane between the hyoid bone and 
thyroid cartilage. 

Thyroid Cartilage. — This is the largest cartilage of the larynx and contains 
the vocal cords. They lie immediately behind or just below the most prominent 

^--Lesser cornu 
Epiglottis^ i: - ' ^'^ 

Greater cornu 



Body of hyoid bone^ ^^ a»r»4_*r»^JHP^^^^t#^C*'"'''^80 triticea 

Thyrohyoid membrane- , ^^^ ^^^ 

'~~***i^l^^^t' I .„Jt^ jf — 'Supenot cornu 

^ I 

Thyroid cartilage 




^^ -Inferior cornu 

Cricothyroid membrane- 

Cricoid cartilage 



Fig. 158. — Side view of hyoid bone and larynx. 

portion of its anterior edge, commonly called "Adam's apple." Since the cartilage 
is large and strong and as age advances tends to calcify, cut-throat wounds, while 
opening the cavity within, do not often pass entirely through the cartilage. This 
cartilage may be fractured by violence. This is often fatal on account of the blood 
flowing into the trachea and lungs below or on account of oedema of the lining mucous 
membrane causing obstruction of the breathing. Thyrotomy or division of the 
thyroid cartilage in the median line is sometimes done to remove foreign bodies or 
new growths. In these cases the voice will be likely to be impaired by the interference 
with the vocal cords. 

Cricothyroid Membrane. — The space between the cricoid and thyroid carti- 
lages is small. This is due to the increase in width of the cricoid as it proceeds back- 
ward. The space is readily felt on the living subject between the thyroid" above and 
the cricoid beneath ; the membrane passes between them. It is crossed by a small 
branch of the superior thyroid artery, the cricothyroid. It is not large enough to cause 
serious trouble. Introducing a tube through this membrane constitutes the operation 



126 



APPLIED ANATOMY. 



of laryngotorny. This operation is but seldom performed. The space is too small 
in many cases, the opening is not made sufficiently low and it is too close to the 
vocal cords. It is an operation of emergency. It is much easier to make a 
quick opening at this point than it is in the trachea below, as it is more superficial 
and is held steady in place by the cartilage above and below it. Even in adults the 
space is sometimes too small to introduce a tube without force and the operation 
should never be done below the age of thirteen. On account of the membrane being 
nearer the surface than is the trachea, a shorter tube should be used. Before intro- 
ducing the tube, care must be taken that the mucous membrane has been thoroughly 
divided, as otherwise the tube will push it before it and slip between the mucous 
membrane and the cartilage and, therefore, not enter the cavity of the larnyx. 

Cricoid Cartilage. — This is much larger posteriorly than anteriorly and fills 
the space between the posterior edges of the thyroid cartilage. Its outside diameter 
is larger than that of the trachea, hence it can readily be felt and forms one of the 
most important landmarks on the front of the neck. It is about opposite the sixth 




Fig. 159. — Examining the interior of the larynx by means of the laryngoscopic mirror. 

cervical vertebra. It is thick and strong and forms a complete circle, being unhke 
the tracheal rings in this respect. It is rare that it is divided in operations. 

For the parts concerned in tracheotomy see the section on the neck. 

Laryngoscopy. — The interior of the larynx is examined by means' of a small 
mirror, i to 3 cm. in diameter, introduced through the mouth and placed just below 
the uvula at an angle of a little more than 45 degrees. The opening of the larynx is 
not directly beneath the mirror but slightly anterior. The base of the tongue and 
lingual tonsils, the glosso-epiglottic folds and pouches, and the epiglottis can be seen 
in front. Posteriorly one sees the two arytenoid cartilages capped with the cartilages 
of Santorini. Between the arytenoids is the commissiire or interarytenoid space. 
To the front and outer side of the tip of the arytenoid cartilages is the cartilage of 
Wrisberg, and running from it forward are the aryepiglottic folds. To the outer 
side of the aryepiglottic fold is the depression called the sinus pyr if ormis. It is here 
that congenital cervical fistulae sometimes open. Near the middle are seen the two, 
white, true vocal cords., and to the outer edge of these are seen the false vocal 
cords. Between these two is the opening of the ventricle of the larynx. The rings 
of the trachea can readily be seen and not infrequently even the point of bifurcation 
of the trachea opposite about the second rib. 



THE NECK. 



127 




Diseases of the Larynx. — Syphilis affects the larynx and produces ulcers. 
These may involve almost any portion but usually they are anterior, involving the 
epiglottis. They are often associated with syphilitic manifestations in the mouth. 
Tuberculosis affects the posterior portion of the larynx and the bulb-like swellings of 
the arytenoids are almost pathognomonic. Ulcers when they occur are most marked 
posteriorly. This affection is associated with a blanching of the mucous membrane 
of the mouth and the presence of a white frothy mucus, which will lead the laryn- 
gologist to suspect the existence of the disease before a view of the larynx is obtained. 

Laryngitis of a simple nature produces a reddening of the cords and a swelling 
of the membrane generally. 

In cedema of the larynx, the serous effusion puffs up the loose mucous membrane, 
particularly of the aryepiglottic folds and epiglottis. 

Tumors both benign and malignant affect the larynx and can at times be seen to 
arise from the vocal cords. 

Paralysis of the muscles is most frequent from interference with the recurrent 



Epiglottis 



Plica ventricularis 
(false vocal cord) 



Ventriculus laryngis 



Plica vocalis (true vocal cord) 

Tuberculum cuneiformi 
(Wrisberg) 

Tuberculum corniculatum 
(Santorini) 

Fig. 160. — View of the larynx as seen-in the laryngeal mirror. 

laryngeal nerve. This nerve supplies the abductor muscles and when paralyzed the 
cords tend to fall together. The nerve may be injured in operations on the neck or 
involved in cancer of the thyroid gland, or oesophagus, or in aneurisms. If one cord 
is paralyzed, the voice is lost temporarily, and when it returns, it is changed in char- 
acter. Paralysis of both nerves does not cause entire loss of voice because the cords fall to- 
gether, but may induce suffocative symptoms ending in death. Paralysis of the left vocal 
cord is believed by Fetterolf and Norris to be due to compression of the left recurrent 
laryngeal nerve between the left pulmonary artery and the aorta or the aortic ligament. 

THE NECK. 

The neck supports the head. It is a pedestal for the head, and is long in pro- 
portion to its thickness; the apparent object of this being to elevate the head and 
allow it to be moved freely in different directions. The animal is thus better enabled 
to discover its enemies and to guard itself against them. 

The various structures of the neck are mosdy long, running between the head 
above and the trunk below. This is the case with the spine, the air- and food-pas- 
sages, the blood-vessels, nerves, and even some muscles, as the sternomastoid and 
trapezius. The shorter structures are either the component parts of the longer 
ones, as the vertebrae of the spine and the rings of the trachea, or are separate 
organs like the larynx, thyroid, and submaxillary glands. The presence of these 
latter organs is not dependent on the length of the neck as is that of the others. In 
the frog, which practically has no neck, the head being placed direcdy on the trunk, 
there sdll exist both larynx and thyroid gland. In the singing birds the vocal 
organ or syrinx is placed in the chest at the bifurcation of the frachea. As regards 
the cervical spine, blood-vessels, air- and food-passages, and muscles, these evidently 
are proportionate to the length of the neck. In the batrachians or frogs there is but 
a single cervical vertebra ; in the swan there are twenty-five cervical vertebra, and in 
the fishes none. In man of course the number of cervical vertebrae remains the same. 



128 APPLIED ANATOMY. 

seven, no matter what the length of the neck. From a consideration of these facts 
we may perhaps state that the neck itself is a subsidiary organ, not of any great im- 
portance in itself, but rather in relation to some other portion of the body — that 
portion being the head. It is the stafi which supports the head by means of the 
cervical spine and muscles. 

The neck contains the great currents of blood which pass to and fro between 
the head and trunk. It carries the air- and food -passages, which run from the mouth 
above to the lungs and stomach below, and incidentally it contains the larynx, the 
thyroid and submaxillary glands, and some lymphatic nodes. The cerebrospinal 
nerves of all the body below the head pass either into the neck or through it to the 
parts beyond. From these facts it becomes evident that, while the neck in itself may 
be a subsidiary organ, for our purposes it is of the greatest importance, because 
interference with its structure either by disease or injury — operative or accidental — 
may destroy the brain above, by interfering with its nourishment, or the body below, 
by interfering with the vital functions of respiration and nutrition, or may paralyze it 
by destroying the conductivity of its nerves. The construction of the neck then 
should be studied with a view of explaining or understanding the diseases and injuries 
of its various parts and the operations performed for their relief. 

Injuries and Diseases of the Neck. — Owing to its exposed position the 
neck is frequently injured by sprains, contusions, cuts, and punctured, gunshot, and 
all sorts of wounds. The cervical spine may become dislocated or fractured and is 
frequently the seat of caries. The muscles become contracted, producing torticollis 
or wry-neck. They may sometimes be ruptured, as in childbirth. 

The arteries are affected with aneurism, necessitating their ligation. They are 
also divided in cut-throat cases and wounds. The veins are of importance in almost 
every operation; bleeding from them is dangerous and may be difficult to control. 

The lymphatic 7iodes are more numerous than elsewhere in the body. Frequently 
they are the seat of tuberculous or sarcomatous enlargement, necessitating their re- 
moval. They may break down and produce wide-spreading and dangerous abscesses, 
which are guided in their course by the fascias ; hence a knowledge of the construc- 
tion of the deep fascias of the neck enables us to understand them. 

The submaxillary and thyroid glands are the seat of enlargement and foreign 
growths requiring the performance of extensive operations for their extirpation. 
Enlargement of the thyroid gland constitutes the disease known as goitre. It is also 
involved in exophthalmic goitre or Graves' s or Basedozv' s disease. 

The ski7i and subcutaneous tisstie become the seat of inflammation and cellulitis. 
In cases of wounds this cellular inflammation may involve the structures beneath the 
deep fascia; this occurs in cut-throat and gunshot wounds. 

The neck is also liable to other affections, such as cysts due to embryological 
defects. Large cysts are formed called hygromas, also sinuses or fistulae, the con- 
ge^iital fistulcE of the neck. The larynx may be the seat of malignant disease; hence 
its removal is undertaken. The operations of tracheotomy , laryngotomy, and cesoph- 
agotomy are also at times necessary. In order to understand these various affec- 
tions and procedures one must be familiar with the construction of the neck, what 
composes it, where the various structures lie and their relation to one another. In 
order to utilize this knowledge we must be able to recognize and identify the 
position of various structures before the skin is incised, for it is rarely that a case 
presents itself with a wound that permits a view of the deeper structures; hence the 
importance of a thorough knowledge of its surface and the structures capable of 
being recognized through the skin. 

SURFACE ANATOMY OF THE NECK. 

For convenience of study we may consider the structures in the median line, 
and those regions anterior and those posterior to the sternomastoid muscle, between 
it and the trapezius. The posterior portion of the neck will be described in the 
section devoted to the back. 

These regions or triangles are simply arbitrary divisions, made for conveni- 
ence of description. They are sometimes spoken of in reference to the location 



I 



THE NECK. 



129 



of growths, operative incisions, etc. They comprise the space between the trapezius 
muscle posteriorly, the median line anteriorly, the clavicle below, and the lower jaw 
above. 

Viewed from in front, the median portion of the neck may be divided into three 
regions, the submental, laryngeal, and tracheal. 

The submental region extends from the chin to the lower border of the body 
of the hyoid bone ; it is limited laterally by the anterior belly of the digastric mus- 
cle on each side. Ranula and other sublingual tumors cause a bulging in this region 
and it is frequently occupied by an enlarged lymphatic node, w^hich at times sup- 
purates and forms an abscess. The floor of the space is formed by the mylohyoid 
muscle and there are no dangerous structures, so that no hesitancy need be had in 
incising abscesses in this locality nor in removing diseased lymph-nodes. In carci- 
noma involving the lower lip near the median line these nodes may be affected and 




Anterior belly of digastno 
Submaxillary gland 

Hyoid bone 
Thyrohyoid membrane 

Thyroid cartilage 
Cricothyroid membrane 
Cricoid cartilage 
Stemomastoid muscle 

-Thyroid gland 



Fig. i6i. — Anterior surface of the neck. 

their involvement in such cases should always be looked for. The submaxillary 
lymphatic nodes farther outward may also be implicated. The tip of the epiglottis 
projects above the hyoid bone in this region. 

The laryngeal region extends from the under surface of the hyoid bone to the 
lower edge of the cricoid cartilage. Laterally it is limited to the space occupied by 
the larynx. The cricoid cartilage is included in this region as a part of the larynx. 
The vocal cords are just beneath the most prominent part of the thyroid cartilage. 

The tracheal region extends from the lower edge of the cricoid cartilage to 
the top of the sternum. Just above the sternum, between the sternal origins of the 
stemomastoid muscles, is the suprasternal notch or, as it is called by the Germans, 
the Juguhim. Laterally the region is limited by the sides of the trachea. 

There are seven or eight rings of the trachea between the cricoid cartilage and 

the top of the sternum. It is covered partly by the sternohyoid and sternothyroid 

muscles. The former in the lower half of their course pass outv.ard, leaving a space 

in which the sternothyroid muscles are seen. The sternohyoid muscle arises from 

9 



I30 



APPLIED ANATOMY. 



the upper and outer portion of the manubrium, the sternoclavicular ligament, and the 
inner end of the clavicle. The origin of the sternothyroid is wider than that of the 
sternohyoid and is lower down. It arises from the first piece of the sternum near the 
median line, below the sternohyoid, and from the cartilage of the first rib. The first 
ring of the trachea is not covered by any important structure. The second, third, 
and fourth rings are covered by the isthmus of the thyroid gland; from here down 
the inferior thyroid veins may lie on the trachea for at least part of their course. The 
anterior jugular vein may exist either as a single vein in the median line or to one 
side of it, or one may pass downward on each side of the median line with a communi- 
cating branch from one to the other crossing the median line in the suprasternal notch. 
The cricothyroid artery, a small branch of the superior thyroid, may cross the crico- 
thyroid membrane, but it is usually too small to cause any troublesome bleeding. 

Structures to be Felt in the Median Line. — On passing the finger down- 
ward from the symphysis it sinks into a hollow, on crossing which the hyoid bone is 



Anterior belly of digastric 



Sternohyoid 

Anterior belly of 
omohyoid 




Submaxillary triangle 



Superior carotid triangle 
Occipital triangle 

Inferior carotid triangle 
Trapezius 

Posterior belly of omohyoid 
• Subclavian triangle 



Fig. 162. — Showing anterior and posterior cervical and subsidiary triangles. 



felt. On pressing the finger into this hollow it rests between the digastric muscles 
on each side and the mylohyoid muscles beneath. Still deeper than the mylohyoid 
are the geniohyoid and geniohyoglossus muscles attached to the genial tubercles on 
the inner side of the mandible. If the lymphatic nodes at this point are enlarged 
they may be felt. (Fig. 161.) 

The hyoid bone can usually be readily felt in the median line. If it is not easily 
discovered in the median line it can be felt by a finger and thumb placed on each 
side of the neck above the thyroid cartilage. 

Passing over the hyoid bone the finger then sinks into the space between it and 
the top of the thyroid cartilage. This space is bridged by the thyrohyoid mem- 
brane. Next comes the thyroid cartilage or "Adam's apple." It can readily be 
seen in adult males and thin people, but in the fat necks of women and children, 
though it can still be felt, it often cannot be seen. The finger then sinks into the 
space between the thyroid cartilage above and the cricoid below. They are con- 
nected by the cricothyroid membrane, over which runs a small branch (cricothyroid) 
of the superior thyroid artery. 



THE NECK. 



131 



The prominence of the cricoid cartilage can be seen in thin people and if care- 
fully searched for can be felt in almost all cases. It is opposite the sixth cervical 
vertebra, a most important landmark. From the cricoid cartilage down to the 
sternum only soft structures can be felt. The sternum projects forward and the 
trachea inclines backward so that opposite the top of the sternum the trachea is about 
2 cm. behind it. The distance between the top of the sternum and cricoid cartilage 
in an adult male is about 4.5 cm. (i^ in.). 

THE CERVICAL TRIANGLES. 

On viewing the neck from the side the prominent sternocleidomastoid muscle 
with its thick anterior and thin posterior edge is seen to divide it into two spaces, 
an anterior and a posterior. They are called the anterior and posterior cervical 
triangles. 



Submaxillary 
lymph-nodes 



Cervical lymph- 
nodes 



External jugular vein 




^ iimaxillary 
gland 

Anterior belly of 
digastric 



Hyoid bone 



Fig. 163.— Submaxillary region, superficial structures. (From a dissection, lymph-nodes enlarged by disease.) 



Anterior Cervical Triangle. 

The anterior cervical triangle has for its anterior side the median line of the 
neck. Its posterior side is the anterior edge of the sternomastoid muscle. Its upper 
side is the lower edge of the mandible from the symphysis to the angle and thence 
across to the mastoid process. The anterior triangle is further divided into the space 
above the digastric muscle called the submaxillary triangle, — from its containing the 
gland of that name, — the stiperior carotid triangle above the anterior belly of the 
omohyoid muscle, and the inferior carotid triatigle below the omohyoid muscle. 

The submaxilliary triangle is so called from its containing the submaxillary 
gland. It is also sometimes called the lingual triangle, from the lingual artery. It 



132 



APPLIED ANATOMY. 



has as its upper side the lower edge of the mandible from near its symphysis around 
the lower edge of the body to the ramus and thence in a straight line across to the 
mastoid process. Its anterior side is the anterior belly and its posterior side is the 
posterior belly of the digastric muscle. The submaxillary gland can usually be felt 
beneath the jaw. Beneath it runs the facial artery to pass over the body of the 
mandible in front of the anterior edge of the masseter muscle. The gland lies on the 
hyoglossus and mylohyoid muscles, which form the floor of this triangle. It is 
encased in a sort of pocket formed by a splitting of the deep cervical fascia. The 
posterior portion of this fascia runs from the styloid process to the hyoid bone and is 
called the stylohyoid ligament. 

Lymphatic nodes lie on the submaxillary gland and in carcinomatous disease 
they become enlarged and then can be readily palpated. In operating on these 



Facial artery 
Lingual artery 

Occipital artery 

External jugular vein 

Edge of sternomastoid 

muscle 

Internal jugular vein- 

Descendens hypoglossi 
nerve 

External carotid arte 
Superior thyroid artery- 




Mylohyoid muscle 
Hyoglossus muscle 
Digastric muscle 

Hypoglossal nerve 

Tendon of digastric 




Fig. 164. — Deeper structures of the submaxillary region, especially the vessels. 



lymphatic nodes for tuberculous disease, care should be taken to distinguish between 
them and the submaxillary gland. The tendon of the digastric muscle does not 
come clear down to the hyoid bone but the loop which binds the two together is 
sometimes a centimetre or more in length. The lingual artery enters the sub- 
maxillary triangle near the apex of the angle formed by the tendon of the digastric. 
It crosses beneath the posterior belly of the digastric muscle and, particularly if the 
digastric muscles contract, it may lie close to the tendon. Frequently the search 
for it is made too high in the triangle and too far away from the hyoid bone. 
When the submaxillary gland is lifted from its bed the hypoglossal nerve is seen 
beneath lying on the hyoglossus muscle. The lingual artery lies beneath the hyo- 
glossus muscle and the muscle is cut through in order to find it. The submaxillary 
region is the seat of Ludwig' s atigina, a septic inflammation involving the cellular 



THE NECK. 



135 



tissues beneath the tongue and jaw around the submaxillary gland and the upper 
portion of the neck. It is a dangerous affection and may cause death not only by 
sepsis but also by oedema of the larynx. 

Dr. T. Turner Thomas {An?ia/s of Surgery, February and March, 1908), has 
pointed out that the infection passes from the inside of the mouth to the submaxil- 
lary region outside by following the connective tissue around the submaxillary gland 
as it winds around the posterior edge of the mylohyoid muscle through the opening 
existing between this muscle in front and the anterior portion of the middle constrictor 
of the pharynx behind. 

The SUPERIOR CAROTID TRIANGLE is limited posteriorly by the sternomastoid 
muscle, superiorly by the posterior belly of the digastric, and inferiorly by the anterior 
belly of the omohyoid. The location of the omohyoid muscle can be determined 
by that of the cricoid cartilage, as the muscle crosses the common carotid artery 
about opposite that point. The sternomastoid muscle can be both seen and felt. 
It is attached above from the apex of the mastoid process to the middle of the 



Mylohyoid 
Hypoglossal nerve 

Digastric 
Submaxillary gland (su- 
perficial portion removed) 

Hyoglossus 




Superior constrictor 
Parotid gland 

Styloglossus 
Middle constrictor 
- Digastric (tendon) 
Stylohyoid (tendoni 

Hyoid bone 
Thyrohyoid 

Inferior constrictor 
Omohyoid 

■ Sternomastoid 

■ Sternohyoid 

Fig. 165. — Submaxillary region. The anterior portion of the submaxillary gland is seen winding around 
and beneath the posterior edge of the mylohyoid muscle. The posterior portion of the gland has been cut 
away. The posterior belly of the digastric and the stylohyoid muscles have also been removed. 



superior curved line on the occipital bone. It is attached below by a sternal head 
to the upper anterior part of the first piece of the sternum, and by a clavicular head 
to the inner third of the clavicle on its superior and interior border. Its action will 
be mentioned in discussing wry-neck. 

Arteries. — The carotid arteries and their branches are found in this triangle. 
The line of the carotid arteries is from a mid-point between the mastoid process and 
the angle of the jaw to the sternoclavicular articulation. The line of the sterno- 
mastoid muscle is from the mastoid process to near the middle of the upper edge 
of the sternum. Thus the carotids are internal to the anterior edge of this muscle above, 
behind the angle of the jaw, and external to it below. The common carotid at its 
upper portion — it ends opposite the upper border of the thyroid cartilage — is just 
about at or close to the edge of the sternomastoid muscle. From the thyroid car- 
tilage up are the internal and external carotids. The internal lies behind and to 
the outer side of the external. The internal gives off no branches until it reaches 
the skull, while the external is practically all branches. Sometimes the external and 
the internal carotids are covered by the anterior margin of the sternomastoid muscle. 
The branches of the external carotid are the superior thyroid, ascending pharyngeal, 
lingual, facial, occipital, posterior auricular, internal maxillary, and temporal. The 



134 



APPLIED ANATOMY. 



superior thyroid or the ascending pharyngeal may either one be the first given off 
by the external carotid, or may come off from the common carotid itself just before its 
bifurcation. 

The superior thyroid artery is given off in the interval between the hyoid 
bone and upper border of the thyroid cartilage. It gives a small iiifrahyoid brarich 
to the thyrohyoid membrane, also a superior laryngeal branch to the inside of the 
larynx. This branch pierces the thyrohyoid membrane in company with the superior 
laryngeal nerve to reach the interior of the larynx. The sternomastoid branch, to 
the muscle of that name, comes oft" at this point and crosses the common carotid artery. 
It is of some importance on this account because in ligating the common carotid 
artery above the omohyoid muscle it is likely to be cut and cause bleeding. Another 
branch of the superior thyroid artery is the cricothyroid. It is small, rests on the 
cricothyroid membrane, and is the first artery liable to be cut in an incision down the 




Digastric 
Mylohyoid" 

Sublingual gland 
Geniohyoid 

Submaxillary ductr 
Submaxillary gland 
Hypoglossal nerve - . Wf. .-hJfci^ 't>'^ ^ ^1-^ ^--^ ^-— Lingual nerve 

Superior constrictor 
Styloglossus 
Parotid gland 
Hyoglossus 
Middle constrictor 
Stylohyoid tendon 
Digastric tendon 

•Thyrohyoid 

■ Inferior constrictor 
■-Omohyoid 
■Btemothyroid 
. Sternohyoid 

Fig. i66. — Submaxillary region — mylohyoid muscle cut away showing the sublingual gland and anterior portion 

of submaxillary gland. 

median line. Bleeding from it is not apt to be serious. The remainder of the 
superior thyroid artery supplies the thyroid gland. 

The ascending pharyngeal is a long slender branch that comes from the 
under side of the main trunk. It lies on the superior and middle constrictors of the 
pharynx and goes clear to the skull, giving off some meningeal branches. In ligat- 
ing the external carotid care should be taken not to include this vessel in the ligature. 
It also gives branches to the soft palate, tonsil, recti capitis antici muscles, and 
tympanum. 

The lingual is given off just below the greater horn of the hyoid bone, and 
passes forward beneath the hyoglossus muscle to supply the tongue and sublingual 
tissues. The hypoglossal nerve lies above the artery and on the hyoglossus muscle. 

The facial comes off just above the lingual artery or often in a common trunk 
with it. It passes upward and forward in a groove in the under surface of the sub- 
maxillary gland and passes over the edge of the jaw at the anterior border of the 
masseter muscle. The facial vein at this point is posterior to it. 

The occipital artery comes off almost opposite the facial. It passes upward 
and backward between the mastoid process and the transverse process of the atlas, 



THE NECK. 



135 



then along in the occipital groove beneath the origin of the sternomastoid muscle, 
the splenius, trachelomastoid, and digastric to make its appearance a Httle to the 
inner side of the middle of a line joining the mastoid process with the external occip- 
ital protuberance. 

The posterior auricular is given off just above the posterior belly of the 
digastric muscle and runs backward and upward on it, then through the parotid 
•gland and up between the external auditory meatus and the mastoid process. In 
ligating the external carotid artery with a view of preventing bleeding in removing 
the Gasserian ganglion, it is endeavored to place the ligature just above the digastric 
muscle and posterior auricular artery in order to preserve the blood supply of the 



Temporal artery 

Internal maxillary 
artery 



External carotid artery 

Posterior auricular 
artery 

Occipital artery 

Hypoglossal nerve 

Internal jugular vein 

Submaxillary gland 

Facial artery 

Internal carotid artery 

Lingual artery 

Superior laryngeal 

nerve 

Descendens hypo- 

glossi nerve 

Superior thyroid artery 
Sternomastoid branch 




Fig. 167. — Carotid arteries and branches. 

tissues above and behind the ear. The internal maxillary and the temporal arteries 
have already been considered. 

Veins. — The veins found in and near the superior carotid triangle are the anterior 
and internal jugulars and their branches. A small portion of the commencement of the 
external jtigular may also be in its extreme upper angle. 

The anterior jugular vein begins just above the hyoid bone from veins in the 
submaxillary and submental regions. It lies on the deep fascia and passes down the 
neck about i cm. from the median line, then just above the sternum it turns down and 
out under the sternomastoid muscle to empty into the external jugular or subclavian. 
At the point of turning it sends off a branch across the median line to the vein on the 
opposite side. Thus the blood-current can pass directly across the neck from one 
external jugular vein to the other. Sometimes there is another communication 
between the two anterior jugulars through a small branch crossing just above or 



136 



APPLIED ANATOMY. 



below the hyoid bone. Instead of two anterior jugular veins there may be onefmt 
this case it is likely to go down the median line of the neck and so be wounded in 
tracheotomy. It receives branches from the inferior thyroid veins and hence may 
bleed freely. It has no valves. 

The internal jugular vein lies to the outer side of and bulges somewhat an- 
terior to the carotid arteries. It is formed by the junction of the inferior petrosal 
and lateral sinuses at the jugular foramen, and passes downward posterior to the 
internal carotid artery and soon reaches its outer side. It receives the facial, lingual, 
pharyngeal, superior and middle thyroid, and sometimes the occipital veins. A large 
communicating branch from the external jugular unites either with the facial or with 
the internal jugular, so that a wound of the external jugular may draw blood directly 
from the internal jugular. 

These tributary veins are superficial to the arteries and in ligating the external 
carotid artery they will have to be displaced. The internal jugular vein is sometimes 



Hyoglossus muscle 

Hypoglossal nerve 

Descendens hypoglossi nerve 

Superior laryngeal nerve 

Omohyoid muscle 

Sternohyoid muscle 
Sternothyroid muscle 
Superior thyroid vein 



Inf. thyroid artery 
Recurrent laryngeal 
nerve 
Sternothyroid 
and hyoid 
muscles 
Inferior thy- 
roid (thyroid- - 
ea ima) vein 

Space of Bums- 




Omohyoid muscle 
Middle thyroid vein 



Digastric muscle 
Mylohyoid muscle 
Facial artery 
Facial vein 

Submaxillary gland 
Hyoid bone 
Lingual artery 

Internal jugular vein 
Superior thyroid artery 
Omohyoid muscle 
Sternohyoid muscle 
Anterior jugular vein 

Cricoid cartilage 

Sternothyroid muscle 



Stemomastoid 



I 



Fig. i68. — Dissection of the deep structures of the front of the neck. 

excised in operations for enlarged lymph-nodes or for infective thrombus. It is not 
eO large above the facial vein as below that point. It becomes so in\'olved in enlarge- 
ments of both tuberculous and carcinomatous lymph-nodes that it may be neces- 
sary to excise it along with the tumor. Its removal does not give rise to any serious 
symptoms. 

It becomes thrombosed by the extension of a thrombus from the transverse 
(lateral) sinus, which in turn becomes affected by the extension of suppurative 
middle-ear disease through the medium of caries of the bones. When the internal 
jugular is thrombosed it is evidenced by swelling, redness, and tenderness along 
the anterior border of the stemomastoid muscle just behind the angle of the jaw. 
Bleeding from the veins in this region is particularly dangerous because the internal 
jugular itself is so large and having no valves, will bleed both from the side towards 
the heart and that towards the head. 

The veins also, which are tributary to it in this region, are so large and are 
wounded so close to the main trunk that the blood from the internal jugular itself 



THE NECK. 137 

regurgitates. The walls of the veins are thin and, if the fascias happen to be relaxed, 
fall readily together and thus are difficult to see, and are so adherent to the fascias as 
not to be readily seized. The surgery of this region requires extreme care and the 
avoidance of haste. 

Nerves. — Lying between the internal jugular vein and the internal and common 
carotid arteries is the pneicmogastric or tenth nerve. It here gives off the superior 
laryngeal nerve, the internal branch of which enters the larynx through the thyro- 
hyoid membrane to endow the interior of the larynx with sensation; the external 
branch goes to supply the cricothyroid muscle. The pneumogastric nerve is fre- 
quently seen in operations in this region. Its division has not been fatal. 

The hypoglossal nerve winds around the occipital artery and goes forward on the 
hyoglossus muscle, which separates it from the lingual artery. The descendens hypo- 
glossi filament leaves the parent nerve as it winds around the occipital artery. It lies 
on the carotid artery in the form of a loop formed by the addition of branches from 
the second and third cervical nerves. As it descends on the sheath of the vessels it 
gives a branch to the anterior belly of the omohyoid muscle. The loop sends 
branches to the sternohyoid, sternothyroid, and posterior belly of the omohyoid, and 
if the nerve is divided paralysis of these muscles will occur. The nerve is to be 
pushed aside when ligating the artery and not included in the ligature. The 
superficial branches from the cervical plexus which come from the middle of the 
posterior edge of the sternomastoid muscle and ramify towards the median line, 
are nerves of sensation, and their division in operative work causes no serious symp- 
toms, hence they are disregarded. The inframaxillary branches of the seventh or 
facial nerve supply the platysma. 

Lymphatics. — The lymphatics are composed of four sets, a superficial set along 
the anterior border of the sternomastoid muscle, a deep set accompanying the great 
vessels, a submaxillary set around and on the submaxillary gland, and a set, two or 
more in number, beneath the chin. 

The S7ib maxillary gland itself not infrequently enlarges and is difficult to dis- 
tinguish from an enlarged lymphatic node. All these glands are at times subjected 
to operative procedures. Fig. 163 shows the submental, submaxillary, and super- 
ficial set of lymphatics enlarged, as w'ell as the submaxillary gland itself. It is taken 
from a tuberculous subject. 

The nodes below and beiiind the jaw become enlarged from diseases affecting 
the tongue, mouth, and throat as well as from affections of the face and scalp. 

The INFERIOR CAROTID TRIANGLE is limited posteriorly by the lower portion 
of the sternomastoid muscle, anteriorly by the median line of the neck, and superiorly 
by the anterior belly of the omohyoid muscle. In this triangle, or reached through it, 
are the lower portions of the common carotid artery and internal jugular vein, with 
the pneumogastric nerve between. Anteriorly are the larynx, trachea, thyroid gland, 
and sternohyoid and sternothyroid muscles. The carotid artery, jugular vein, and 
pneumogastric nerve lie partly in the triangle but rather under the edge of the 
sternomastoid muscle. Operations on the air-passages, laryngotomy and tracheot- 
omy; on the thyroid gland, thyroidectomy; and ligation of the common carotid 
artery and removal of lymph-nodes are all done in this triangle. The superficial 
and deep lymphatics accompany the vessels; there are also some in Burns' s space 
above the sternum. In children, instead of the innominate artery ceasing at the 
sternoclavicular articulation, it sometimes rises above it and may be wounded in 
operation on the trachea. The thyroidea ima artery, if present, will lie on the 
trachea, coming up from the innominate or directly from the aorta. 

Posterior Cervical Triangle. 
The posterior cervical triangle has as its base the middle third of the clavicle; 
its anterior side is the posterior edge of the sternomastoid muscle; its posterior side 
is the anterior edge of the trapezius; its apex is at the point of junction of these two 
muscles at the superior curved line of the occiput. It is customary to divide it into 
two triangles by the posterior belly of the omohyoid muscle. The upper triangle is 
large and is called the occipital triaiigle. The lower triangle is small and is called 
the subclavian triangle. This division by the posterior belly of the omohyoid 
muscle is not always satisfactory. The muscle runs upward and inward in a line 



138 



APPLIED ANATOMY. 



from about the junction of the outer and middle thirds of the clavicle to a variable 
distance, up to 2.5 cm. (i in.), above the clavicle at the anterior edge of the sterno- 
mastoid muscle. The omoyhoid muscle has its lower attachment at the posterior 
edge of the suprascapular notch, which is below the level of the clavicle and its 
posterior belly is sometimes concealed behind the clavicle and does not rise above it 
except at its inner extremity beneath the sternomastoid muscle. It is rare that any 
distinct triangle is formed, hence as far as the surface markings are concerned 
there is often no subclavian triangle. Therefore the posterior cervical triangle will 
be considered. as a whole and not divided. 

It is covered by the skin, beneath which is the subcutaneous tissue, which at its 
lower portion contains the fibres of the platysma muscle. Its floor is composed 
from above downward of the splenius, levator scapulcc, scalenus posticus, scalemis 
7nediiis, and scale?iiis anticiis muscles. The deep fascia of the neck spans the 
space and splits anteriorly to enclose the sternomastoid muscle and posteriorly to 



Occipitalis major nerve 
Occipital artery 
Occipitalis minor nerve 

Splenius muscle 

Auricularis magnus nerve 

Superficial cervical nerve 

Levator scapulae muscle 

Spinal accessory nerve 

Trapezius 

Middle scalene muscle 

Posterior scalene muscle 
External jugular vein 

— ■— Omohyoid muscle 




Sternomastoid muscle 
Anterior scalene muscle 

Phrenic nerve. \ 
Internal jugular vein 
Omohyoid muscle 

Transverse cervical 

artery 

Brachial plexus 

Suprascapular artery 

Subclavian vein 

Subclavian artery 

Fig. 169. — Dissection of the posterior cervical triangle. 

enclose the trapezius. The space contains important arteries, veins, nerves, and 
lymphatics. 

External Jugular Vein. — Lying on the deep fascia and beneath the super- 
ficial fascia and platysma is the external jugular vein. This begins below the ear 
and posterior to the ramus of the jaw, being formed by the union of the temporo- 
maxillary and posterior auricular veins. It passes downward and slightly backward 
on the surface of the sternomastoid muscle to its posterior border, which it reaches at 
about the middle and follows down until about a centimetre above the clavicle; here 
it pierces the deep fascia and dips behind the clavicular origin of the sternomastoid 
muscle to empty into the subclavian. It has one pair of valves about 4 cm. above 
the clavicle, and another pair at its point of entrance into the subclavian. They do 
not entirely prevent a regurgitation of the blood. 

The external jugular vein receives the posterior external jugular vein, and the 
suprascapular and transverse cervical veins. The occipital may also enter into it. 
The veins of the neck are exceedingly irregular in their formation and may vary 
considerably. The external jugular is readily seen through the skin, it may be 
made more prominent by compressing it just above clavicle. In operations in this 



THE NECK. 139 

region of the neck in some cases it is necessary to divide this vein; in others one 
may be able to a\oid it, at all events it should be recognized before the incision is 
made. Behind the angle of the jaw there is usually a branch communicating with 
the facial, lingual, or internal jugular vein, and just above its lower extremity it is 
enlarged, forming the part called the sinus. For these reasons, if the vein is cut low 
down near the clavicle or high up near the angle of the jaw bleeding is liable to be 
free. The \-al\'es are not competent to prevent the reflux of blood and it therefore 
drains the large internal jugular abo\'e and the subcla\ian below. The attachment 
of the vein to the deep fascia, as it pierces it above the clavicle, tends to keep its 
lumen open when the vein is divided and favors the entrance of air into the circula- 
tion. The size of the veins in the posterior triangle varies according to those in the 
anterior. If the anterior and external jugulars are large the posterior and internal 
jugulars are apt to be small. 

Arteries. — The arteries in the posterior cervical triangle are the subclavian, the 
transverse cervical, and sometimes the S2ipr as capillar when it runs above the clavicle 
instead of behind it. The line of the subclavian is from the sternoclavicular joint to 
the middle of the clavicle. It rises about 1.25 cm. (^ in.) above the clavicle. The 
clavicular origin of the sternomastoid muscle covers the inner third of the clavicle so that 
the subclavian artery is only visible in the posterior cervical triangle from the outer 
edge of this muscle to the middle of the clavicle. Both the suprascapular and 
transverse cervical arteries are given off from the thyroid axis, which arises from the 
first portion of the subclavian just internal to the scalenus anticus muscle. Therefore 
at their origin they are both considerably above the level of the clavicle, but as they 
proceed outward they incline downward, and on leaving the outer edge of the sterno- 
mastoid muscle the suprascapular is usually behind the clavicle while the transverse 
cervical runs parallel to it and a short distance ( i cm. ) above it, where it can be 
felt pulsating. 

The posterior belly of the omohyoid muscle can be represented by a line drawn 
from the anterior edge of the sternomastoid muscle opposite the cricoid cartilage, 
obliquely down and out to the junction of the middle and outer thirds of the clavicle. 
It is superficial to the transverse cervical artery and at its inner end is above it. 
These arteries and their accompanying veins will be encountered in operating in 
these regions for the removal of lymphatic nodes. 

Nerves.— The nerves in the posterior cervical triangle are the spinal accessory, 
branches of the cervical plexus, and the brachial plexus. The position of the spinal 
accessory is important because it is frequently encountered in operations for the 
removal of enlarged lymphatic nodes. It enters the under surface of the sternomastoid 
muscle from 3 to 5 cm. below the tip of the mastoid process and emerges at the pos- 
terior edge about its middle or a little above. It is about at this point that the 
external jugular vein reaches the posterior border of the sternomastoid, and the cervical 
plexus, formed by the anterior divisions of the four upper cervical nerves, reaches 
the surface. From this point also the occipitalis minor runs upward along the posterior 
edge of the sternomastoid and the aiiricularis viag?ius runs upward over the sterno- 
mastoid direct to the external ear. The superficial cervical runs directly across the 
muscle towards the median line and the descending branches — the sternal, clavicular, 
and acromial — pass down beneath the deep cervical fascia to perforate it just above the 
clavicle and become cutaneous. Care should be taken not to mistake them for the 
spinal accessory. Still deeper are the cords of the brachial plexus. These cords, 
sometimes two, at others three in number, are beneath the deep fascia and lie above 
the subclavian artery. They can be felt and in a thin person, if the head is turned to 
the opposite side, the prominence which they form under the skin can even be seen. 

Lymphatics. — The lymphatics of the posterior cervical triangle are numerous 
and being often enlarged are frequently operated on. They lie along both the outer 
side of the internal jugular vein and under the posterior edge of the sternomastoid 
muscle, which they follow clear up to the base of the skull. They also follow the edge 
of the trapezius muscle and lie in the space between it and the sternomastoid; they 
extend downward under the clavicle and become continuous with the axillary 
lymphatics. The right and left lymphatic ducts empty into the venous system at 
the junction of the innominate and internal jugular veins. That on the left side is 



I40 



APPLIED ANATOMY 



called the thoracic duct ; it begins as the receptaculum chyli on the body of tne 
second lumbar vertebra and is about 45 cm. (18 in.) long. It drains all the left side 
of the body and the right as far up as and including the lower surface of the liver. 

The duct on the right side is called the right lymphatic djict ; it is only i or 2 
cm. in length and drains the right side of the head and neck, the right upper ex- 
tremity, and the right side of the chest as far down as and including the upper surface 
of the liver. 

TORTICOLLIS OR WRY-NECK. 

In this affection the head and the neck are so twisted that the face is turned 
toward the side opposite the contracted muscle and looks somewhat upward. It is 
usually caused by some affection of the sternomastoid muscle. It is not always the 
only muscle involved, as the trapezius and others may likewise be affected. It is 
congenital or acquired. In the congenital cases it is caused by an injury to the 




Fig. 170. — Torticollis or wry-neck. 

Sternomastoid muscle, occurring during childbirth; a swelling or tumor may be 
present in the course of the muscle. In the acquired form the distortion may be 
more or less permanent and may be due to caries or other disease of the spine. In 
such cases it is evident that treatment is to be directed to the diseased spine rather 
than to the sternomastoid muscle, which will be found to be relaxed. 

Inflammation of the lymph-nodes of the neck may cause the patient to hold the 
head and neck in a distorted position. The wry-neck in this case will disappear as 
the cause subsides. Rheumatic affections of the neck are a common cause, and the 
sternomastoid muscle may then become contracted and require division. In rare 
instances a nervous affection causes a spasmodic torticollis. The persistent move- 
ments render this a very distressing affection, and to relieve it not only has the 
sternomastoid but also the trapezius been divided, and even the spinal accessory and 
occipital nerves have been excised. 

Division of the sternomastoid muscle should be done by open and not by sub- 
cutaneous incision. The sternal origin of the sternomastoid muscle is a sharp, dis- 
tinct cord, but its clavicular origin is a broad, thin band extending outward a third of 
the length of the clavicle. An incision 2 or 3 cm. or more in length is made over 
the tendon and the bands are to be carefully isolated before being divided. The 
structure most important to avoid is the internal jugular vein. It lies close behind 
the sternal origin of the muscle and great care must be taken to avoid it. In one 
case in which it was accidentally wounded it was necessary to ligate it. As the 



THE NECK. 141 

deep fascia of the neck splits to enclose the sternomastoid muscle it is opened by 
the operation and infection has caused in such cases wide-spread phlegmonous 
inflammation. 

ARTERIES OF THE NECK.— LIGATION. 

Carotid and Subclavian Arteries and Branches. — Both these arteries are 
affected at times with aneurisms, necessitating their ligation. Ligation of the main 
trunks or their branches is also required in various operations on the head, as in re- 
moval of the Gasserian ganglion or maxilla, or excision of the tongue, thyroid gland, 
etc. The communication between the arteries on the two sides of the body is quite 
free, as also is that between the arteries above and those lower down. For this 
reason bleeding from the distal end of a cut artery will be almost as free as from its 
proximal end. The various branches of the external carotid anastomose across the 
median line of the body. The vertebrals communicate above through the basilar. 
The internal carotids communicate through the anterior cerebral and anterior com- 
municating and with the basilar through the posterior communicating and posterior 
cerebral. Between the parts above and those below we have the superior thyroid 
anastomosing with the inferior thyroid branch of the thyroid axis from the subclavian 
artery. The princeps cervicis, a branch of the occipital, anastomoses with the as- 
cending cervical branch of the inferior thyroid, the transverse cervical of the thyroid 
axis, and the profunda cervicis from the superior intercostal. These free communi- 
cations enable the surgeon to ligate to any extent without incurring the risk of gan- 
grene. The line of the carotid arteries is from a point midway between the mastoid 
process and the angle of the jaw to the sternoclavicular articulation. At the upper 
iDorder of the thyroid cartilage the common carotid divides into the internal and ex- 
ternal carotids; this is opposite the fifth cervical vertebra. 

Common Carotid Artery. — This lies on the longus colli muscle and a small 
portion of the rectus capitis anticus, which separate the artery from the transverse 
processes of the vertebrae. The artery can be compressed against the vertebrae and 
its pulsations stopped by pressing backward and slightly inward. It is superficial in 
the upper portion of its course but becomes deeper as it approaches the chest. The 
anterior tubercle of the transverse process of the sixth cervical vertebra is called 
Chassaignac' s tubercle. It is about opposite the cricoid cartilage. It is one of the 
guides to the artery. The omohyoid muscle crosses the artery opposite the cricoid 
cartilage and just above it is the site of election for ligation. 

Ligation of the Common Carotid Artery. — In making the incision, which should 
be 5 or 6 cm. long, it should be laid along the anterior edge of the sternomastoid 
muscle with its middle opposite to or a little above the level of the cricoid cartilage. 
This incision may be a little anterior to the direct line of the artery as given from 
midway between the angle of the jaw and mastoid process to the sternoclavicular 
articulation. This is because the muscle bulges forward and overlaps and hides the 
artery. The artery is beneath its edge. On cutting through the superficial fascia and 
platysma the deep fascia is reached, some small veins perhaps being divided in 
so doing. The deep fascia is divided along the edge of the sternomastoid muscle, 
which is then pulled outward. Beneath it and running obliquely across the lower 
portion of the wound is the omohyoid muscle. It is recognized by the direction of 
its fibres, they being more or less transverse or oblique. Sometimes a small artery, 
the sternomastoid branch of the superior thyroid, crosses the common carotid just 
above the omohyoid muscle. The artery is also crossed by veins. The lingual, 
superior, and middle thyroid veins all pass over it to enter the internal jugular. 
The middle thyroid vein may be above or just below the omohyoid muscle. 
These vessels all pass transversely across the artery and beneath the deep fascia. 
The artery lies in a separate sheath to the inner side of the jugular vein. In the 
living body it is to be recognized by its pulsations. The vein being filled with blood 
may overlap the artery. Veins are readily emptied of their blood by pressure on 
the parts during the operation; hence if the vein happens to be collapsed it may not 
be recognized and is liable to be wounded. Therefore in examining for the artery see 
that the pressure from the retractors or other sources does not obstruct the flow of 



142 APPLIED ANATOMY. 

blood through the jugular vein. Running down on the anterior surface of the 
artery is the descendens hypoglossi nerve. If seen it should be pushed aside. It 
supplies the sternohyoid, sternothyroid, and both bellies of the omohyoid muscles. 
The pneumogastric nerve lies posteriorly, between the artery and the vein. Care 
will be necessary to avoid including it in the ligature. The ligature is to be carried from 
the outer to the inner side, the needle being passed between the vein and the artery. 
Ligation of the Common Carotid Artery Below the Omohyoid Mnscle.—T\^^-3X\.^x:y 
below the omohyoid muscle becomes deeper and less accessible. The sternomastoid 
muscle overlaps it and is less easily displaced. The sternohyoid and sternothyroid 
muscles likewise tend to encroach on it and have to be drawn inward. The internal 
jugular vein and carotid artery diverge as they descend, so that at the level of the 
sternoclavicular joint they are separated 2.5 cm. In this interval the first portion 
of the subclavian artery shows itself. The anterior jugular vein will probably be 
encountered along the edge of the sternomastoid muscle, and near the omohyoid 




Sternomastoid artery 
Common carotid artery 
Descendens hypoglossi nerve 
~" Internal jugular vein 
Sternomastoid muscle 
Omohyoid muscle 

Fig. 171. — Ligation of the common carotid artery. 

muscle the artery will be crossed by the middle thyroid vein. Still lower it may be 
that the inferior thyroid will be encountered. Posterior to the carotid artery is the 
inferior thyroid artery, coming from the thyroid axis and going to the thyroid gland, 
and winding around from posteriorly to the inner side is the recurrent laryngeal 
nerve. The ligating needle is to be passed from without inward. 

Collateral Circulation After Ligation of the Commofi Carotid Aj'tery. — When 
the common carotid has been tied the blood reaches the parts beyond from the 
branches of the carotid of the opposite side and from the subclavian artery of the 
same side. The branches of the external carotid anastomose across the median line. 
This is particularly the case with the superior thyroid and facial. The internal 
carotids communicate by means of the circle of Willis. From the subclavian the 
vertebral artery communicates by means of the basilar with the circle of Willis. 
The thyroid axis by its inferior thyroid branch communicates with the thyroid 
arteries of the opposite side. An ascending branch of the inferior thyroid as well as 
one from the transverse cervical, also from the thyroid axis, anastomose with 
branches of the princeps cervicis, which is a descending branch of the occipital. 



THE NECK. 



143 



Finally the superior intercostal, which, like the vertebral and thyroid axis, is a 
branch of the first portion of the subclavian, through its profunda cervicis branch 
anastomoses with a deep descending- branch of the princeps cervicis (Fig. 172). 

The Internal Carotid Artery. — The internal carotid Hes posterior and to 
the outer side of the external. It gi\es off no branches in the neck. Entering the 
skull through the carotid canal, in the apex of the petrous portion of the temporal 
bone and directly below and to the inner side of the Gasserian ganglion, it passes 
through the inner side of the caver?ioHS sm/ts and at the anterior clinoid processes it 
bends up to divide into the anterior and middle cerebrals. Before its division it 
gives off the posterior comtminicating artery, the anterior choroid artery to supply 
the choroid plexus in the lateral ventricles, and the ophthalmic artery. The internal 



Temporal 

Posterior auricular 

Occipital 

Princeps cervicis 

Superficial branch 

Deep branch 

Internal carotid 



Transverse cervical 
Suprascapular 




Transverse facial 
Internal maxillary 

Ascending pharyngeal 
Facial 

Lingual 

External carotid 
Superior thyroid 



Inferior thyroid 

Common carotid 

Vertebral 
Thyroid axis 
Innominate 



Superior intercostal 



Subclavian 



Fig. 172. — Collateral circulation after ligation of the common carotid artery. 

carotid artery in the neck is normally straight, but sometimes, particularly in elderly 
persons, it is tortuous. This may then be mistaken for aneurism. It lies about 2 cm. 
posterior and a litde to the outer side of the tonsil. As the pharynx is the side of 
least resistance, when the vessel becomes tortuous it bulges into it, and on examina- 
tion through the mouth a pulsating swelling can be distinctly seen in the pharynx 
just posterior to the tonsil. The finger introduced can feel the pulsations, and 
pressure on the carotid in the neck below causes the pulsations to cease. Thus the 
character of the pulsating swelling can be recognized. This artery is rarely ligated, 
but if it is desired to do so it can readily be reached through an incision 6 or 7 cm. 
long behind the angle of the jaw. Aneurism or wounds may necessitate its ligation. 
At its commencement it is comparatively superficial, but as it ascends it gets quite 
deep, passing beneath the digastric and stylohyoid muscles. It should therefore be 
ligated below the angle of the jaw and not over 3 cm. from its origin at the upper 



144 



APPLIED ANATOMY. 



border of the thyroid cartilage. It will be necessary to push the sternomastoid 
muscle posteriorly, as its anterior margin ox'erlies the vessel. The internal jugular 
vein is to its outer side and between the two and posterior is the pneumogastric 
nerve. The sympathetic 7ierve lies behind it but is separated by a layer of fascia and 
is not liable to be caught up in passing the aneurism needle. The lingual, facial, 
and laryngeal veins may be encountered and are apt to cause trouble. They will 
have to be held aside or ligated and divided. The ascending pha?yngeal artery may 
lie close to the internal carotid and care should be taken not to include it in the 
ligature. The needle is to be passed from without inward. 

The External Carotid Artery. — Of recent years the external carotid artery 
has been ligated far more often than formerly, as it was customary to ligate the 
common carotid instead. The external carotid runs from the upper border of the 
thyroid cartilage to the neck of the mandible. It supplies the outside of the head, 
face, and neck. These parts are the seat of various operations for tumors, especially 
carcinoma of the mouth and tongue, diseased lymph-nodes, and other affections, and 



Facial artery 
Lingual artery, 

Greater comu of 
hyoid bone 
Superior laryn- 
geal nerve 
Ext. carotid artery 

Superior thyroid 
artery 




Stylohyoid muscle 

Digastric muscle 

Occipital artery 

Hypoglossal nerve 

Descendens hypoglossi 

nerve 

Internal carotid artery 



Internal jugular vein 
Superior thyroid vein 
Sternomastoid artery 
Common carotid artery 

"Fig. 173. — Ligation of external carotid artery and its branches. 

the external carotid and its branches are not infrequently ligated in order to cut off 
their blood supply. 

In extirpation of the Gasserian ganglion, hemorrhage has been such an annoying 
and dangerous factor that a preliminary ligation or compression (Crile) of the 
external carotid is frequently resorted to. This artery may also be ligated for 
wounds, resection of the upper jaw, hemorrhage from the tonsils, and angiomatous 
growths affecting the region which it supplies. 

Unlike some other arteries the external carotid sometimes seems to have no 
trunk, consisting almost entirely of branches. Therefore in ligating it one should 
not expect to find a big artery the size of the internal carotid, but often one only half 
as large. The branches of the external carotid artery are the superior thyroid, lin- 
gual, and facial, which proceed anteriorly toward the median line ; the occipital 
and posterior auricular, which supply the posterior parts ; the ascending phary^igeal, 
which comes off from its deep surface and ascends to the base of the skull ; and 
the temporal and internal inaxillajy arteries, which are terminal. It is ligated either 
near its commencement just above the superior thyroid artery or behind the angle 
of the jaw above the digastric muscle. 

Ligation of the External Carotid Aj'tery above the Superior Thyroid. — At its 
commencement at the upper border of the thyroid cartilage the artery is quite 



THE NECK 



MS 



superficial, being covered by the skin, superficial fascia, platysma, deep fascia, and 
overlying edge of the sternomastoid muscle. It is to be reached through an incision 
5 cm. in length along the anterior edge of the sternomastoid muscle in a line from 
the sternoclavicular joint to midway between the angle of the jaw and the mastoid 
process. The middle of the incision is to be opposite the thyrohyoid membrane. 
The bifurcation of the common carotid artery is an important landmark. 

The superior thyroid artery is given off at the very commencement and some- 
times even comes from the common carotid just below. The ascending pharyngeal 
is the next branch, about i cm. above the superior thyroid. It comes off from the 
deep surface of the artery ; almost opposite to it and in front is the lingual. It will 
thus be seen that the distance between the lingual and the superior thyroid, where 
the ligature is to be placed, is quite small. The superior thyroid is about opposite 
the upper border of the thyroid cartilage, while the lingual is opposite the hyoid 
bone. Beneath the artery is the superior laryngeal nerve, but it is not liable to be 
caught up by the needle in passing the ligature because it lies fiat on the constrictors 
of the pharynx and is apt to be a little above the site of ligation. 

The veins are the only structures liable to cause trouble. They are superficial 
to the arteries. On account of their irregularity more may be encountered than is 
expected. The superior thyroid and lingual veins both cross the artery to empty 
into the internal jugular. The facial vein is also liable to be met, as the facial artery 
frequently springs from a common trunk with the lingual. The communicating 
branch between the facial and external jugular vein is another one that should be 
anticipated. These veins, when it is possible, are to be hooked aside; otherwise 
they are to be ligated and cut. Great care should be taken not to mistake a vein 
for the artery. It might appear an easy matter to readily recognize the artery and 
distinguish between it and the veins, but this is not always the case in the living 
subject. The veins may have some pulsation transmitted to them from the adjacent 
arteries and the artery may temporarily ha\e its pulsations stopped by pressure from 
the retractors. The li\'ing artery touched by the finger seems soft and does not give 
the hard, resisting impression felt in palpating the radial in feeling the pulse. The 
difference in thickness of the coats is also sometimes not apparent at a first glance. 

The ligature is to be passed from without inward so as to guard against wounding 
the internal carotid. 

Ligatio7i of the Superior Thyroid Artery. — The superior thyroid is the first 
branch of the external carotid and is given off close down to the bifurcation or even 
from the common carotid itself just below. It lies quite superficial but of course 
beneath the deep fascia. At first it inclines upward and then makes a bend and goes 
downward to the thyroid gland. It gives off three comparatively small branches, 
the hyoid along the lower border of the hyoid bone, the sternomastoid to the muscle 
of that name, and the superior laryngeal to the interior of the larynx. The larger 
portion of the artery goes downward to supply the thyroid gland and muscles over 
it, therefore the artery is to be looked for at the upper edge of the thyroid cartilage, 
and not near the hyoid bone. The incision is the same as for ligating the external 
carotid low down, viz. , 5 cm. along the anterior edge of the sternomastoid muscle, its 
middle being opposite the upper edge of the thyroid cartilage. Veins from the thyroid 
gland — superior thyroid — will probably cover it. After the deep fascia has been 
opened, the external carotid is to be recognized at its origin from the common carotid 
and then the superior thyroid artery found and followed out from that point. The 
ligature is to be passed from above downward to avoid the superior laryngeal nerve. 
This nerve lies distinctly above the artery and is not liable to be injured if the thyroid 
artery is followed out from its origin at the external carotid. Treves suggests ligat- 
ing it between the sternomastoid and superior laryngeal branches, but it is more 
readily reached closer to the external carotid artery. 

Ligation of the Lingual Artery. — The lingual artery may be ligated for wounds, 
as a preliminary step to excision of the tongue, and to check the growth of or bleed- 
ing from malignant growths of the tongue, mouth, or lower jaw. 

The lingual artery springs from the external carotid opposite the hyoid bone 
about I cm. above the bifurcation of the common carotid. It is composed of three 
parts: the first, from its point of origin to the posterior edge of the hyoglossus 



146 



APPLIED ANATOMY. 



muscle; the second, the part beneath the hyoglossus muscle; and the third, the part 
beyond this muscle to the tip of the tongue. 

The artery is usually ligated beneath the hyoglossus muscle in the second part of 
its course, although it is sometimes desirable to ligate it in the first part of its course. 

The Jirst part inclines upward and forward, above the greater horn of the hyoid 
bone, to the hyoglossus muscle, beneath which it passes in a direction somewhat 
parallel to the upper edge of the hyoid bone. It lies on the middle constrictor of 
the pharynx and superior larnygeal nerve and is covered by the skin, platysma, and 
fascia. It lies immediately below the stylohyoid and digastric muscles and is crossed 
by the hypoglossal nerve and some veins. This portion frequently gives of? a hyoid 
branch which runs above the hyoid bone. It is often missing, in which case the 
parts are supplied by the hyoid branch of the superior thyroid. From either the end 
of the first part or the beginning of the second part, the dorsalis linguae branch arises. 

The second part of the lingual lies on the superior constrictor and geniohyoglos- 
sus muscles and is covered by the hyoglossus. It runs in a direction somewhat 
parallel to the upper edge of the hyoid bone and from 0.5 to i cm. above it. In this 




/ 



Mylohyoid muscle 

Submaxillary gland — 

Anterior belly of 
digastric muscle 



Lingual artery 

Tendon of 
digastric muscle 




Hypoglossal nerve 
vLingual vein 
vCut edge of the hyoglossus muscle 
Fig. 174. — Ligation of the lingual artery 

part of its course it is usually accompanied by one or two veins and the hypoglossal 
nerve is superficial to it, the hyoglossus muscle separating them. This is the part 
of the artery chosen for ligation. An incision is made, convex downward, running 
from below and to one side of the symphysis nearly down to the hyoid bone and 
then sloping upward and back, stopping short of the line of the facial artery, which 
can be determined by the groove on the mandible just in front of the masseter muscle. 
The skin, superficial fascia, and platysma having been raised, the submaxillary gland 
is seen covered with a comparatively thin deep fascia. Some veins coming from the 
submental region may then be encountered. They may be ligated and divided. 
The submaxillary gland is next to be lifted from its bed and turned upward against 
the mandible, carrying with it the facial artery, which is adherent to its under sur- 
face. The tendon of the digastric will now be seen with the anterior and posterior 
belHes of the muscle forming an angle with its point toward the hyoid bone. These 
with the hypoglossal nerve form what has been called the triangle of Lesser. It is 
in this space that the artery is ligated. The floor of the space posteriorly is formed 
by the hyoglossus muscle, while anteriorly is seen the edge of the mylohyoid muscle. 
Through the thin fascia overlying the hyoglossus muscle can be seen the hypoglossal 



THE NECK. 147 

nerve, and below it, sometimes a vein. The artery lies under the muscle, while the 
veins may be either on or under the muscle or both. 

The apex of the angle formed by the tendon of the digastric muscle is held 
down to the hyoid bone by a slip of fascia which is an expansion of the central 
tendon of the muscle and the tendon of the stylohyoid muscle. The distance at 
which the central tendon of the digastric is held away from the hyoid bone varies 
in different individuals and is an important fact to bear in mind in searching for 
the artery. If the tendon rests high above the hyoid bone the artery must be 
looked for low down, sometimes even under the tendon; if, on the contrary, the 
tendon is low down the artery may be o. 5 to i cm. higher up. The hypoglossal nerve 
lies on the muscle and nearer to the mandible than the artery. If there is a vein on 
the hyoglossus muscle it is apt to be below the nerve, that is, nearer the hyoid bone, 
and may lie directly o\er the artery. The vein and the nerve are to be displaced 
up towards the jaw and an incision a centimetre long made through the hyoglossus 
muscle a short distance above the digastric tendon and parallel with the hyoid bone. 
This incision should not be deep, as the muscle is only 2 or 3 mm. (^ in.) thick. 




Middle scalene muscle 

Posterior scalene muscle 



Stemomastoid muscle, ^ ^ ^ t , \ 

^^ y^ / \ \ \ ^"-Omohyoid muscle 

Phrenic nerve 

Anterior scalene muscle . 

Subclavian vein I l \ Suprascapular artery and vein 

Cords of brachial plexus / Transverse cervical artery and vein 

Subclavian artery 

Fig. 175. — Ligation of the subclavian artery 

The edges of the incision being raised and displaced upward and downward, the artery 
will probably be seen running at right angles to the fibres of the muscle and parallel to 
the hyoid bone. If not seen at once it should be looked for below the incision, 
nearer to the hyoid bone. Care must be taken not to mistake the vein for the artery. 
That this is not an unlikely thing is shown by its occurring in the hands of a distin- 
guished surgeon who had had exceptional experience in this same operation. The 
ligature needle may be passed from above downward to avoid including the hypo- 
glossal nerve. 

Subclavian Artery. — The right subclavian artery runs from the sternoclavicular 
articulation in a curved line to the middle of the clavicle. It rises 1.25 cm, (^ in,, 
Walsham) above the clavicle. The innominate bifurcates opposite the right sterno- 
clavicular joint. The left subclavian springs direcdy from the arch of the aorta, 
therefore it is longer than the right by 4 to 5 cm., this being the length of the in- 
nominate. As the subclavian artery passes outward it is crossed by the scalenus 
anticus muscle, which divides it into three parts : the first part, extending to the 
inner side of the muscle, gives off three branches, the vertebral, internal majnmary , 
and thyroid axis; the second part, behind the muscle, gives off the superior intercos- 
tal; the third part has no branches. 



148 APPLIED ANATOMY. 

1^\\Q first portion of the siibclavian lies very deep and operations on it have been 
so unsuccessful that they have been practically abandoned. As it is frequently 
involved in aneurisms its relations are worth studying. In approaching the artery 
from the surface it is seen to be covered by the sternomastoid, the sternohyoid, 
and the sternothyroid muscles. The outer edge of the sternomastoid muscle corre- 
sponds with the outer edge of the scalenus anticus. The three first-named muscles 
having been raised, the artery is seen to be crossed by the internal jugular, the 
vertebral, and perhaps the anterior jugular veins. The anterior jugular above the 
clavicle dips beneath the inner edge of the sternomastoid muscle to pass outward 
and empty into the external jugular or subclavian. The pneumogastric nerve crosses 
the artery just to the inner side of the internal jugular vein. Below, the artery rests 
on the pleura, and on the right side the recurrent laryngeal nerve winds around it. 
Behind the artery are the pleura and lung, which rise somewhat higher in the neck 
than does the artery. 

On the left side the phrenic nerve leaves the scalenus anticus muscle at the first 
rib, crosses the subclavian at its inner edge, and passes down on the pleura to cross 
the arch of the aorta. To the inner side of the artery runs the thoracic duct, which, 
as it reaches the upper portion of the artery, curves over it to cross the scalenus 
anticus muscle and empty into the junction of the internal jugular and subclavian 
veins. The trachea and oesophagus are likewise seen to the inner side of the artery. 
The thyroid axis comes of? its anterior surface, the vertebral from its posterior, and 
the internal mammary below. 

The second portion of the subclavian artery lies behind the anterior scalene 
muscle. In front of the anterior scalene is the subclavian vein. The phrenic nerve 
runs on the muscle and at the first rib leaves it to continue down between the right 
innominate vein and pleura. Behind and below, the artery rests on the pleura and 
the middle scalene muscle is to its outer side. Thus it is seen that the artery passes 
through a chink formed by the anterior scalene muscle in front and the middle 
scalene behind. They both insert into the first rib. The posterior scalene is farther 
back and inserts into the second rib. Above the artery are all the cords of the 
brachial plexus. One branch of the subclavian, the superior intercostal artery, is 
given off near the inner edge of the anterior scalene muscle. 

The third portio7i of the subclavian runs from the outer edge of the anterior scalene 
muscle to the lower border of the first rib. This part of the artery is the most super- 
ficial. The only muscle covering it above is the thin sheet of the platysma, lower 
down the subclavius muscle and clavicle overlie it; but the operations on the vessel 
are done above these structures, hence they do not interfere. There are apt to be a 
number of veins in front of the artery. The external jugular and transverse cervical 
veins are certain to be present and perhaps the suprascapular and cephalic, which 
may enter above instead of below the clavicle. These veins may form a regular net- 
work in the posterior cervical triangle above the clavicle and prove very troublesome. 
Above is the brachial plexus and transverse cervical artery and still higher is seen the 
omohyoid muscle. The suprascapular artery is lower down and usually concealed 
just below the upper edge of the clavicle. The lowest cord of the brachial plexus, 
formed by the first dorsal and last cervical nerves, may be posterior to the artery. 
The nerve to the subclavius muscle passes down in front of it. 

Ligation of the Third Portion of the Subclavian Artery. — The head is to be 
turned strongly to the opposite side and the shoulder depressed. This lowers the 
clavicle and raises the omohyoid muscle and therefore gives more room to work. 
The skin is to be drawn down and an incision 7.5 cm. long made on the clavicle. 
The drawing down of the skin is done to avoid wounding the external jugular vein. 
This vein is really fastened to the deep fascia, and the skin, platysma, and super- 
ficial fascia slide over it. On releasing the skin it slides up above the clavicle. The 
middle of the incision should be a little to the inside of the middle of the clavicle. 
The deep fascia is to be incised and the clavicular origin of the sternomastoid 
and trapezius muscles cut to the same extent as the superficial incision. The length 
of the adult male clavicle is about 15 cm (6 in.). 

The clavicular origin of the sternomastoid extends out on the clavicle one-third 
of its length. The trapezius inserts into the outer third. This leaves the middle 



THE NECK. 149 

third or 5 cm. of the cla\'icle on its upper surface JFree from muscles. As the 
incision is 7.5 cm. long this necessitates the division of 2.5 cm. (i in.) of muscle, 
and as the middle of the incision is a little to the inner side of the middle of the 
clavicle this will make it necessary to divide more of the clavicular origin of the 
sternomastoid than of the trapezius. After the division of the deep fascia, fat and 
veins are encountered. The scalenus anticus muscle has the subclavian vein in 
front of it and the artery behind, therefore the vein must be attended to before a 
search is made for the edge of the scalene muscle. The veins to be encountered are 
the external jugular vein, which empties into the subclavian in front of or to the 
outer side of the anterior scalene muscle, and its tributaries, the suprascapular and 
transverse cervical veins, as well as the anterior jugular and a communicating branch 
from the opposite side of the neck. The cephalic vein not infrequently sends a 
communicating branch over the clavicle to empty into the external jugular. The 
fat is to be picked away with forceps; the veins are to be held out of the way with a 
blunt hook or ligated and cut. The suprascapular artery may be seen close to or 
under the cla\icle. The transverse cervical artery may perhaps be above the level 
of the wound. The omohyoid muscle may or may not be seen, as its distance from 
the clavicle is quite variable. The transverse cervical and suprascapular arteries 
are not to be cut, as they are needed for the collateral circulation. As was 
mentioned in speaking of the ligation of the external carotid artery, so also here it 
is not always easy to distinguish between arteries and veins. The veins being 
disposed of, the anterior scalene muscle is to be sought at the internal portion of the 
wound. It runs somewhat like the lower portion of the sternomastoid, the posterior 
edges of the two muscles coinciding. The phrenic nerve runs down first on the 
anterior surface and then on the inner surface of the scalenus anticus. The edge of 
the muscle being recognized, by following it down the finger feels the first rib. The 
artery lies on the first rib immediately behind the muscle and the vein immediately in 
front of the muscle. The tubercle on the first rib may not be readily felt because the 
muscle is inserted into it. The prevertebral fascia coming down the scalenus anticus 
muscle passes from it to the subclavian artery, forming its sheath; hence, as pointed 
out by George A. Wright, of Manchester {^Annals of Surgery, 1888, p. 362), the 
edge of the muscle may not readily be distinguished and the brachial plexus is a 
better guide. This is above the artery and the lower cord of the plexus lies directly 
alongside of the artery. It is closer to the artery above and to its outer side than 
the subclavian vein is below and to its inner side. The greatest care should be 
exercised in passing the aneurism needle around the artery. The vein is not so 
much in jeopardy as are the pleura and lowest cord of the brachial plexus, hence the 
needle is passed from above down between the ner\-e and the artery and brought 
out between the artery and vein. 

Wounding of the pleura may cause collapse of the lung and later a septic 
pleurisy, while including the nerve will cause severe pain, etc. 

Collateral CircidaUon after Ligation of the Third Portion of the Subclavian Artery. 
— (1) Internal mammary with superior thoracic and long thoracic. (2) The poste- 
rior scapular branch of the suprascapular with the dorsalis branch of the subscap- 
ular. (3) Acromial branches of suprascapular with acromial branch of acromial 
thoracic. (4) A number of small vessels derived from branches of the subclavian 
above with axillary branches of the main axillary trunk below (Gray). 

Ligation of the Inferior Thyt'oid Artery. — The inferior thyroid artery, unlike 
the superior, lies deep from the surface, and it is a far more difificult vessel to reach. It 
is a branch of the thyroid axis, the other branches being the transverse cervical and 
suprascapular. The thyroid axis comes from the first part of the subclavian just a 
little to the inner side of the edge of the scalenus anticus muscle. The inferior 
thyroid artery ascends on the longus colli muscle, just to the inner side of the 
scalenus anticus and almost in front of the vertebral artery. When it reaches about 
the level of the sexenth cervical vertebra it bends inward and behind the carotid 
artery to reach the lower posterior edge of the thyroid gland. The transverse 
process of the sixth cervical vertebra, called the caj'otid tubercle of Chassaignac, is 
above it. As it bends to go inward it gives off the ascending cervical artery. In 
front of the artery are the internal jugular vein, common carotid artery, pneumo- 



15° 



APPLIED ANATOMY. 



gastric nerve, and the middle ganglion of the sympathetic. The recurrent laryngeal 
nerve usually passes upward behind the branches of the artery just before they enter 
the thyroid gland. The thoracic duct on the left side passes over the front of the 
artery low down. 

Operation. — An incision 7.5 cm. long is made along the anterior border of the 
sternomastoid muscle, extending upward from the clavicle. This will bring the upper 
extremity up to, or even above, the cricoid cartilage. The anterior jugular vein 
will have to be ligated and the muscle displaced outward. The common carotid 
artery should then be isolated and it, together with the pneumogastric nerve and 
internal jugular vein, drawn outward. The omohyoid muscle may appear at the 
upper edge of the incision. Feel for the carotid tubercle on the sixth transverse 
cervical process: the artery lies below the omohyoid muscle and cricoid cartilage and 
below the tubercle and beneath the sheath of the carotid. If the trunk of the sym- 
pathetic or its middle cervical ganglion, which lies on the artery, is encountered, it 



Profunda cervicis 
Transverse cervical 



Posterior scapular 



Acromial thoracic 



Subscapular 
Dorsalis scapulae 

Long thoracic 




Inferior thyroid 
Common carotid 
Vertebral 
Innominate 



Superior intercostal 
— Subclavian 
/ ~ -Superior thoracic 
— - Internal mammary 



Fig. 176. — Collateral circulation after ligation of the third portion of the subclavian artery. 

should be pushed to the inner side, the artery isolated outwardly and ligature applied. 
Do not go too far out or the scalenus anticus will be reached and the phrenic nerve 
may be injured, nor too far in, to avoid wounding the recurrent laryngeal. 

The thyroidea hna {inferior thyroid^ vei^is do not cross outward nor accompany 
the artery, but proceed downward on the trachea to empty into the innominate veins. 



THE CERVICAL FASCIAS. 

There are two fascias in the neck, the superficial and the deep. The super- 
ficial fascia has blended with it anteriorly the platysma muscle and the termination of 
the nerves, arteries, and veins. The main trunks of these structures lie for all 
practical purposes beneath the superficial fascia and adherent to the surface of the 
deep fascia. It is for this reason that in raising the superficial structures the larger 
trunks remain applied to the deep fascia and are thus less liable to be injured in the 
living and mutilated in the dead. In the superficial fascia and on the deep fascia are 
the superficial lymphatics. 



THE NECK. 



151 



The superticial lymphatic nodes frequently suppurate. When they do the 
abscess so formed is prevented by the deep fascia from reaching the parts beneath, so 
the pus works its way out through the skin. As the superficial fascia is loose, if 
the. abscess is slow in formation, it may extend for a considerable distance under the 
skin. 

Sebaceous cysts are common in the neck. As they are superficial to the deep 
fascia, which is not involved, they can be removed without fear of wounding any 
important structures. The veins do not overlie them; they are always superficial 
to the veins, therefore there is no danger of wounding the external jugular. 

The Deep Cervical Fascia. — The deep cervical fascia completely envelops 
the neck and sends its branches in between all its various structures. It is the 
fibrous tissue that both unites and separates all the different structures to and from 
each other. Where this fascia is abundant it forms a distinct layer, but where it is 
scant it is simply a small amount of connective tissue between two adjacent parts. 



Anterior jugular veins 



Larynx^ 
Superficial layer of deep cervical fascia, 
Pretracheal layer 
Cricoid cartilage 

Cricothyroid muscle 
Prevertebral layer 
LoDgus colli 



Sternohyoid muscle 
Sternothyroid 
Thyroid gland 
/ Omohyoid 



Carotid artery 
Sternomastoid 



Trachelomastoid 



Sixth vertebra 




Longus colli 

Internal jugular vein 
Trachelomastoid 



Scale 



> anticus and medius 



External jugular vein 
Scalenus posticus 

Levator scapuLc 
Splenius colli 
Splenius capitis 



Trapezius 

Com plexus 
Multifidus spinoe 
Semispinales cervices 
Fig. 177. — Transverse section of the neck through the sixth cervical vertebra. 

To follow all the processes of the deep fascia through the neck between its innumer- 
able structures is impossible — nor is it necessary. The main reason for studying the 
deep cervical fascia and its various parts is to understand the course pursued by 
abscesses and infections. This is best done by limiting oneself to the main super- 
ficial layer and some of the larger layers crossing from side to side. 

The principal layers of the deep cervical fascia are the stiperjicial layer, which 
completely encircles and envelops the neck, the prevertebral layer, which passes 
from side to side in front of the spinal column, and the pretracheal layer, which passes 
from side to side in front of the trachea. 

The Superficial Layer. — The superficial layer of the deep fascia envelops the 
whole of the neck, with the exception of the skin, platysma, and superficial fascia. 
It is attached above to the occipital protuberance, the superior curved line of the occi- 
put, the mastoid process, then blends with the capsule of the parotid gland, then passes 
to the angle of the jaw and along the body of the mandible to the symphysis, 
whence it proceeds around the opposite side in the same manner. Below it is 
attached to the sternum, upper edge of the clavicle, acromion process and spine of 
the scapula, thence across to the vertebral spines, to which and to the ligamentum 



APPLIED ANATOMY. 

nuchae it is attached up to the occipital protuberance. In the front"oF the neck it 
passes from the mandible down to be attached to the hyoid bone and thence down- 
ward to the sternum and clavicle. 

From the under side of this superficial layer processes of fascia come oE and 
envelop the various structures of the neck. Every separate structure of the neck 
is covered by it and therefore separated from the adjacent parts by a more or less dis- 
tinct layer of the fascia. In many places it is quite thin or almost imperceptible, 
amounting to but a few shreds of fibrous tissue, in other places it is more distinct, 
forming more or less marked capsules, as in the case of the thyroid and submaxillary 
glands, or fibrous layers, as in the case of those in front of the vertebrae and trachea. 
Posteriorly in the median line the superficial layer of the deep fascia sends a process 
which covers the under surface of the trapezius muscle. Anteriorly another process 
is given ofl to cover the under surface of the sternomastoid muscle. The super- 




Prevertebral fascia 
Pneumogastric nerve 
Common carotid artery 
Internal jugular vein 
Sheath of the vessels 

Superficial layer of deep fascia 

CEsophagus 

Trachea 

Thyroid gland 

Pretracheal fascia 



4 



Fig 178. — Deep cervical fascia. 



The pharynx and larynx have been cut away, exposing the prevertebral and 
pretracheal layers. 



ficial veins of the neck, the anterior, external, and posterior jugulars, lie on or in 
the deep fascia, being stuck to or blended with its upper surface. 

About 3 cm. ( I ^ in. ) above the sternum the deep fascia splits into two layers, 
one to be attached to the anterior and the other to the posterior edge of the sternum 
in front of the sternohyoid and sternothyroid muscles. Between these two layers is 
the space of Bums ; it contains the lower ends of the anterior jugular veins with 
the branch that joins them, some fatty tissue and lymphatic nodes, and the sternal 
origin of the sternomastoid muscle. Sometimes a vein comes up from the surface of 
the chest below to open into the anterior jugular vein. 

The prevertebral layer passes from side to side directly on the bodies of the 
vertebrae. It covers the muscles attached to the spine, as the scalene, longus colli, 
rectus capitis anticus, and also the nerves, as those of the brachial plexus, coming 
from the spine. On reaching the carotid artery and jugular vein it helps to form 
their sheath. Its upper edge is attached to the base of the skull at the jugular fora- 
men and carotid canal and thence across the basilar process to the opposite side. 
Inferiorly it passes down on the surface of the bodies of the vertebrae into the pos- 
terior mediastinum. 



THE NECK. 153 

From the sheath of the vessels outward, beyond the posterior edge of the sterno- 
mastoid muscle, the prevertebral fascia covers the scalene muscles, the brachial plexus 
of nerves, and the subclavian artery. On reaching the clavicle the fascia is attached 
to its upper surface, blending with the superficial layer; it is then continued down 
over the subclavian muscle, forming its sheath, and ends as the costocoracoid mem- 
brane. The part over the subclavian artery and vein is continued over them and 
the brachial plexus and follows them into the axilla. This fascia forms the floor of 
the posterior cervical triangle; the roof is formed by the superficial layer of the deep 
fascia. It is between these layers that the suprascapular artery and veins nm. The 
descending branches of the cervical plexus, the spinal accessory nerve, omohyoid 
muscle, and some fat and lymph-nodes are also found there. 

The pretracheal layer passes from side to side in front of the trachea. Laterally 
it too blends with the sheath of the vessels and is continued posteriorly behind the 
pharynx and oesophagus as the buccopharyngeal fascia. In front it blends in the 
median line with the superficial layer and is attached to the hyoid bone and cricoid 
cartilage. It splits to enclose and form a capsule for the thyroid gland, and below en- 
closes in its meshes the inferior thyroid veins, and thence passes to the arch of the 
aorta to be continuous with the pericardium. Laterally it passes under the sterno- 
hyoid, omohyoid, and sternothyroid muscles to blend with the sheath of the vessels 
and the layer on the posterior surface of the sternomastoid muscle. This is its 
lateral limit. Underneath the sternomastoid muscle a loop of fascia proceeds down- 
ward from the omohyoid muscle to the first rib. This is derived from the sheath 
of the vessels beneath and the layer on the under surface of the sternomastoid 
superficially. 

The sheath of the vessels envelops the carotid artery, jugular vein, and pneumo- 
gastric nerve. Thin layers of fascia pass between these structures, separating one 
from the other. The sheath is formed by the union of the outer edge of the pre- 
tracheal fascia and the prevertebral fascia, with the fascia lining the under surface of 
the sternomastoid muscle. This sheath follows the vessels down into the chest and 
out into the axilla. 

The capsule of the parotid gla^id is formed by the splitting of the superficial 
layer of the deep cer\ical fascia as it passes from the mastoid process to the angle of 
the jaw. Its superficial portion is attached to the zygomatic process. Its deep por- 
tion passes from the styloid process to the angle of the jaw and is known as the 
stylomandibular ligament. 

The capsule of the submaxillary gland \s formed by a splitting of the superficial 
layer at the hyoid bone. It forms the covering of the gland and from the hyoid 
bone sends a process upward which lies on the digastric and mylohyoid muscles 
and follows the latter up to be attached along the mylohyoid ridge of the mandible. 
It proceeds with the submaxillary gland around the posterior edge of the mylohyoid 
muscle to cover its upper surface. The stylomandibular ligament alluded to above 
separates the parotid from the submaxillary gland. 

The capsule of the thyroid gland is not very thick and the gland is readily 
separated from it, as is also the case w ith the submaxillary gland. It is continued 
downward in front of the trachea as the pretracheal layer and laterally it blends with 
the sheath of the vessels. It follows the vessels downward into the chest and is 
continuous with the pericardium. The veins of the gland, which are at times very 
large, run beneath the capsule and bleed freely if wounded. 

The Buccopharyngeal Fascia. — Between the pharynx in front and the ver- 
tebral column behind is the retropharyngeal space. The fascia forming the pos- 
terior wall of this space is the prevertebral fascia already described. Forming its 
anterior wall is a thin layer of connective tissue called the buccopharyngeal fascia. 
It invests the superior constrictor of the pharynx and is continued forward on the 
buccinator muscle. It is continued downward behind the pharynx and oesophagus 
into the posterior mediastinum: laterally it blends with the sheath of the vessels 
and is continuous with the pretracheal fascia around the larynx, trachea, and thyroid 
gland (Fig. 179). 

Abscesses of the Neck. — Abscesses of the neck usually arise in connection 
with the Ivmphatic nodes. They may also start from infected wounds, carious 



■54 



APPLIED ANATOMY. 



teeth, suppuration of the thyroid g-land, and other causes. They may have then^ 
course influenced by the various layers of the deep fascia. 

Pus in the Submaxillary RegioJi. — As the submaxillary space has the mylo- 
hyoid muscle as its floor, abscesses here show below the body of the mandible 
between it and the hyoid bone. Usually they point towards the skin. Infection of 
this space may occur from the teeth. Tillmans ("Surgery," vol. i, p. 434) saw a 
case in which in four days the pus caused death from infection of the mediastinum 
and pleura. This proceeded downward from a badly extracted tooth and thence 
under the deep fascia of the neck to the chest. 

The pus, filling the submaxillary space, as can also occur in Ludwig's angina, 
which is an infective inflammation of the submaxillary and sublingual regions, may 
follow the lingual and facial arteries to the sheath of the great vessels and down into 
the superior mediastinum. The infection in Ludwig's angina may pass around 
the posterior edge of the mylohyoid muscle and involve the structures around the 



Buccinator 



Masseter 



Internal pterygoid 



Buccopharyngeal 
fascia 

Retropharyngeal 
space 

Prevertebral fascia 




Posterior pilla* 
of fauces 

External carotid artery 
Parotid gland 



Internal jugular vein 



Rectus capitis 



Longus colli 



Vagus nerve 
Internal carotid artery 



Fig, 179 — Section through the upper portion of the third cervical vertebra, showing the buccopharyngeal and 
prevertebral fascias and retropharyngeal space. 

base of the tongue and pharynx, and produce oedema of the larynx and death (see 
page 200). 

Pus superficial to the deep fascia tends to perforate the skin and discharge 
externally. If it is slow in forming it may sink down and pass over the clavicle 
onto the upper portion of the chest. 

Pus in the suprasternal notch or space of Burns bulges anteriorly but may 
perforate posteriorly. The sternothyroid and sternohyoid muscles are attached to the 
posterior surface of the sternum ; but the layer of fascia on their anterior surface is 
very thin, so that pus may either pass between the muscles or perforate them and so 
pass down in front of the pretracheal fascia close to the under surface of the sternum. 
It would then tend to show itself in the upper intercostal spaces, close to the 
sternum. 

Pus between the pretracheal and S7iperficial layers, as may occur from abscesses 
of the thyroid gland, tends to work its way downward rather than laterally. The 
pretracheal fascia at the sides blends with the sheath of the vessels and the fascia 
covering the posterior surface of the sternomastoid muscles. In this space lie the 
sternohyoid, sternothyroid, and omohyoid muscles. The pretracheal fascia is beneath 
them and the superficial layer of the deep fascia above. Pus can follow the posterior 



THE NECK. 



155 



surface of these muscles down behind the sternum in front of the innominate veins 
and arch of the aorta. 

Pus between the pretracheal and prevertebral layers cannot go further to one 
side than the sheath of the \'essels. Therefore it follows the trachea and oesophagus 
down into the posterior mediastinum. This space, between these layers, is some- 
times called the visceral space because it contains the oesophagus, trachea, and 
thyroid gland. Pus in this space can also perforate into the trachea, pharynx, 
oesophagus, or even extend laterally and involve the great vessels. 

If the anterior portion of the thyroid gland suppurates, the pus may perforate the 




Prevertebral layer 
Cricoid cartilage 



Hyoid bone 



Thryoid cartilage 

Superior layer of deep 
cervical fascia 



Pretracheal layer 
Cricoid cartilage 

Thyroid gland 
Space of Bums 

Left innominate vein 

Aorta 

Pericardium 



Fig. i8o. — The superficial layer, pretracheal layer, and prevertebral layer of the deep cervical fascia. 



thin pretracheal fascia covering it and pass down behind the sternohyoid and sterno- 
thyroid muscles into the anterior part of the superior mediastinum. 

Pus posterior to the prevertebral fascia, as from caries of the vertebrae, if high 
up may bulge into the pharynx, forming a retropharyngeal abscess. It may follow 
the scaleni muscles and brachial plexus down around the axillary artery into the 
axilla. In the neck it shows itself posterior to the carotid arteries and to the older 
edge of the sternomastoid muscles. 

Pus i7i the sheath of the great vessels, when originating from lymphatic nodes, 
may first raise the sternomastoid muscle and show itself along its anterior border; 
it may perforate the lumen of the vessels; it may pass down with the vessels into the 
superior mediastinum; or it may bulge into the visceral space between the pre- 
vertebral and pretracheal layers and follow the trachea and oesophagus down into the 
chest. Should it tend outwardly it may break into the posterior cervical triangle 
between the prevertebral and superficial layers and show itself above the clavicle. 



156 APPLIED ANATOMY. 

Retropharyngeal Abscess. — Pus which tends to point into the pharynx may come 
from disease of the vertebrae, in which case it is posterior to the prevertebral fascia; 
or it may originate from the lymphatic nodes in the retropharyngeal space. 

When coming from caries of the vertebrae, it may point either in the pharynx 
or, pushing its way outward, pass behind the great vessels and show itself behind 
the outer edge of the sternomastoid muscle. I have seen it point in both these 
places in the same case. When originating in the retropharyngeal space it lies in 
front of the prevertebral fascia and behind the buccopharyngeal fascia. It either 
points forward into the pharynx or, going down, follows the posterior surface of the 
oesophagus into the posterior mediastinum. It may also perforate the oesophagus 
and enter its lumen. 

Pus in the Posterior Cervical Triangle. — If above the prevertebral layer this 
bulges directly forward and tends to open through the skin. Its progress downward 
is obstructed by the attachment of the superficial layer to the top of the clavicle as 
it blends with the prevertebral layer. If pus is beneath the prevertebral layer it may 
then follow the brachial plexus and subclavian artery down beneath the clavicle and 
appear in the axilla. The attachments of the costocoracoid membrane tend to direct 
the pus laterally under the pectoralis minor muscle into the axilla rather than to allow 
It to come forward on the anterior portion of the chest. 

LYMPHATICS OF THE NECK. 

The lymphatics of the neck are both superficial and deep. The superficial 
nodes communicate freely with and end in the deep ones. For the sake of conven- 
ience we may divide them into a transverse set, embracing the submental^ submaxillary, 
superficial upper cervical (behind the angle of the jaw), posterior auriciilar, and 
occipital nodes; and two longitudinal sets, one along the great vessels and another, a 
posterior set, in the posterior cervical triangle. 

The Transverse Lymphatics. — The stibmental nodes, also called the supra- 
hyoid, lie beneath the chin and drain the region of the lower lip and chin and anterior 
part of the floor of the mouth. These will be enlarged in children with ulcerative skin 
affections of these regions. They may also be involved in carcinoma of the lower lip, 
especially if near the median line. That the submental nodes drain the tissues of the 
anterior portion of the mouth and probably the tongue itself is shown by Henry T. 
Butlin ("Surgery of Malignant Disease," p. 153), who states that the submental 
nodes are frequently affected in carcinoma of the tongue when its tip is involved. 

The submaxillary nodes are beneath the body of the mandible in the sub- 
maxillary triangle. They drain the lips, nose, floor of the mouth, gums, anterior 
portion of the tongue and side of the face. These are the nodes most frequently 
affected in carcinomatous affections of the lips and anterior portion of the tongue. 
Henry T. Butlin ("Surgery of Malignant Disease," p. 153) calls attention to the 
fact that in malignant disease of one side of the anterior portion of the tongue the 
lymphatics of the opposite side may also be involved, thus showing that the lym- 
phatics of the two sides of the tongue freely anastomose. This is contrary to what 
exists as regards the arteries, which anastomose hardly at all across the median line. 
He also states that one or more of the lymphatic nodes is frequently imbedded in the 
substance of the submaxillary gland. Therefore the submaxillary gland is excised at 
the same time as the affected lymphatic nodes. 

The superficial tipper cervical {subparotid) nodes are just below the parotid 
lymphatics and behind the angle of the jaw. They drain tlie region embraced by 
the masseter muscle as far back as the ear. They may be enlarged in affections of 
the skin and scalp above. Therefore in children with enlargement of these nodes 
the source of infection should be sought in those regions. 

The poste7'ior auricular nodes are behind the ear on the mastoid process and 
insertion of the sternomastoid muscle. In practice they are encountered as small 
(i cm.), round swellings behind the ear, which are usually quite tender to the touch. 
This is probably due to their being placed on a hard, bony base. When enlarged 
they are often the subject of operations. 






THE NECK. 



157 



The superficial occipital yiodes are just below the superior curved Hue of the 
occiput oi" a little lower down in the hollow below the occiput between the posterior 
edge of the sternomastoid and anterior edge of the trapezius muscles, resting on the 
splenius. These are the nodes that are enlarged in syphilis and are to be searched 
for in endeavoring to establish a diagnosis. 

Superficial and Deep Abodes. — • The five sets of nodes just described, viz. , the 
submental, submaxillary, superficial upper cervical, posterior auricular, and superficial 
occipital, are all regarded as superficial nodes. As a matter of fact this division of the 
lymphatic nodes into superficial and deep is not of practical value. The communica- 
tion between the various nodes is quite free. Adjacent nodes communicate and the 
superficial nodes communicate with the deep ones below. 

On account of this an afTection is not always limited to a single node but often 
involves those to each side and those lying still deeper. In the submaxillary region 



Posterior 
auricular node 



Anterior 
auricular node 



Occipital node 




Superior deep 
cervical nodes 



Superficial 
cervical nodes 



Fig. i8i. — Superficial lymphatic vessels and nodes of head and neck; semidiaerammatic. (Piersol.) 

the nodes will almost certainly be found to lie under the fascia along with the sub- 
maxillary gland. When the occipital nodes are enlarged they may not only be 
found in the space already described but also on the adjacent trapezius and sterno- 
mastoid muscle and even beneath the outer edge of the trapezius below the deep 
fascia. 

The Longitudinal Lymphatics. — These are along the great vessels, — the 
anterior cervical lymphatics, — and in the posterior cervical triangle. 

The anterior cervical lymphatics is the name given to those which tend to show 
in the anterior cervical triangle either beneath or in front of the sternomastoid 
muscle, between it and the median line. There are some nodes in the median line 
but they are almost all deep down in the neck above the sternum. The other nodes 
may be either superficial or deep, mostly deep, along the edge of the sternomastoid 



T'^y ^^^^^ APPLIED ANATOMY. ^^^^^^^^^H 

muscle. They follow the sheath of the vessels. This is a very extensive chain of 
nodes. They may extend in all directions. As regards depth they may be on the 
deep fascia along the edge of the sternomastoid or following the external jugular 
vein. If deeper they follow the internal jugular vein and carotid artery directly 
up to the base of the skull, also behind and below the mastoid process and along- 
side of the transverse process of the atlas (first cervical vertebra). They extend 
under the sternomastoid posteriorly, deep in the suboccipital region. Should 
they be enlarged downward they will protrude behind the posterior edge of the 
sternomastoid into the posterior cervical triangle; if anteriorly they will follow it 
down into the space of Burns in front of the trachea and thence into the superior 
mediastinum. 

T\\& posterior cervical nodes show behind the posterior edge of the sternomastoid, 
along the edge of the trapezius, and also above tne clavicle. They not infrequently 
fill the posterior cervical triangle and extend beneath the muscles on each side. 

Below they may be continuous with enlarged nodes in the axilla and extend 
anteriorly under the sternomastoid into the pretracheal region and mediastinum. 
They are frequently excised for both tuberculosis and carcinoma. In so doing 
particular care is to be taken on account of the trans\'ersalis colli and suprascapular 
arteries and veins, with which they may lie in contact, as well as the terminal por- 
tion of the external jugular. 

Postpharyngeal Nodes. — In ihe retropharyngeal space, toward the sides, 
between the buccopharyngeal fascia in front and the prevertebral fascia behind are 
located one or two nodes (see buccopharyngeal fascia, page 153, and retropharyn- 
geal abscess, page 156). They seem to be the starting point, sometimes, of retro- 
pharyngeal abscess. They do not appear to get enlarged and project into the 
pharynx as tumors, as might be expected, so that they are not subjected to any 
surgical procedures. 

Operating for the Removal of Enlarged Cervical Nodes. — This opera- 
tion may be one of the most serious in surgery. Sir Frederick Treves says : " An 
operation of this kind should not be undertaken unless the surgeon has perfect con- 
fidence in his practical knowledge of the anatomy of the neck. Scarcely an instance 
can be cited in the range of operative surgery where a knowledge of the structure 
and of relations is more essential than in these excisions." The main difficulties 
encountered are in the avoidance of nerves and the control of hemorrhage. Air 
may enter the veins and cause death, and the thoracic duct may be wounded. The 
latter accident sometimes results fatally. The difficulty of the operation will de- 
pend on the size and number of the nodes, their location, and the character of the 
inflammation or other changes they have undergone. In an early stage the nodes 
may be lying loose in the tissues and can be readily turned out when once exposed. 
Later they may be matted to the surrounding structures by inflammatory deposits 
and then their separation is a matter of difficulty and danger. 

The skin incisions may be either longitudinal or more or less transverse. The 
longitudinal incisions are usually along either the anterior or posterior border of 
the sternomastoid muscle, or the anterior edge of the trapezius. The transverse 
incision may be either opposite the hyoid bone — when it may be prolonged around 
the angle of the jaw and up to the mastoid process and over the suboccipital glands, 
or above the clavicle. 

As the skin and superficial structures are cut and the deep fascia opened, 
the superficial veins will be cut, hence the first anatomical fact to be borne in mind 
is the probable location of the veins. The most important of these is the external 
jugular. The internal jugular below the hyoid bone lies under the sternomastoid 
muscle and therefore is protected until the deeper dissection is begun. The external 
jugular runs about in a line from the angle of the jaw to the middle of the posterior 
edge of the sternomastoid muscle and thence downward to about the middle of the 
clavicle. Therefore an incision along the posterior edge of the sternomastoid will 
divide it at about the middle of the muscle, and the surgeon should be prepared to 
guard against an undue loss of blood when it is cut. Opening into the external 
jugular posteriorly between the middle of the sternomastoid muscle and the clavicle 
below are the posterior jugular, the transverse cervical, and the suprascapular veins. 



THE NECK. 159 

These latter open into the external jugular i or 2 cm. above the clavicle and are 
almost certain to be cut in operations in the supraclavicular fossa. An incision 
along the anterior edge of the sternomastoid low down will cut the anterior jugular 
vein a short distance above the sternum as it winds beneath the sternomastoid to 
empty into the external jugular. An incision along the anterior border of the 
sternomastoid from its middle up is bound to cause free hemorrhage. The external 
jugular behind the angle of the jaw communicates with the facial, which empties into 
the internal jugular; hence division of the external jugular at this point also drains 
the blood almost directly from the internal jugular. A carelessly deep incision may 
wound the internal jugular itself in the region posterior to the hyoid bone. The 
internal jugular is more superficial at this point than it is lower down. The temporo- 
maxillary and posterior auricular veins will also be cut behind the ramus of the jaw. 

Not only are veins cut but also nerves. The middle of the posterior edge 
of the sternomastoid is the point of departure of several nerves. The superficial 
cervical runs directly transversely inward toward the thyroid cartilage. The auricu- 
laris magnus goes up to the lobe of the ear, and the occipitalis minor follows the 
posterior edge of the muscle up to the occiput. These three nerves are nerves of sen- 
sation and if they are divided only a certain amount of temporary anaesthesia will be 
produced over the parts they supply, hence their division is not a matter of much 
moment. The auricularis magnus is the largest of the three. The descending 
branches of the cervical plexus, which leave the posterior edge of the sternomastoid 
muscle immediately below the nerves just mentioned, proceed down under the deep 
fascia and will be seen only in a deeper dissection. The nerve which it is absolutely 
important to avoid is the spinal accessory. This enters the sternomastoid muscle 
on its under surface some little distance back of its anterior edge and 3 to 5 cm. 
below the mastoid process. It sends a branch to the muscle and leaves its posterior 
edge about its middle. It then passes downward and outward across the posterior 
cervical triangle under the deep fascia to enter the deep surface of the trapezius. If 
this nerve is divided, paralysis of the trapezius will certainly follow and as it is a 
motor nerve the shoulder of that side will drop considerably. This will be a perma- 
nent deformity because motor nerves do not seem to have their functions restored 
by time as so usually occurs when the nerves of sensation are divided. 

If the nodes to be removed are superficial ones there are no other structures to 
be feared and the operation will be an easy one. If they lie deeper, then the sheath 
of the sternomastoid muscle is to be divided and the muscle pulled outward. Just 
above the level of the cricoid cartilage a small artery, the sternomastoid branch of 
the superior thyroid, enters the muscle and it will be divided. As the sternomastoid 
is raised and pulled outward care must be taken to avoid wounding the spinal 
accessory nerve. As this nerve enters the muscle from 3 to 5 cm. below the mastoid 
process and some distance back from the edge of the muscle, if it is necessary to 
divide the muscle it is best done high up above the entrance of the nerve, or low 
down. By so doing the nerve supply (from the spinal accessory) and blood supply 
are not interfered with and the function of the muscle is not so much impaired as 
it would be if divided near the middle. The nodes not only possess their own 
capsule but also a covering from the connective tissue in which they lie. There- 
fore to remove them they must be detached and separated from it usually by blunt 
dissection. When these strands of fibrous tissue from the nodes to the surrounding 
parts are strong they have to be caught with forceps and cut. They are to be 
clamped, to avoid possible bleeding. When the angle of the jaw is reached the 
communicating branch between the facial and external jugular veins must be 
clamped and cut. The parotid gland is to be pulled upward and inward. The 
nodes may stick to the jugular vein and carotid artery. The vein is on the outside 
and is likely to be the first encountered. When distended it overlies the artery. 
If collapsed its presence may not be suspected. Feel for the pulsation of the carotid 
artery and avoid the structure just to its outer side. The jugular vein may be so 
involved in the mass as to necessitate its removal. In such a case remember that 
posteriorly between it and the carotid artery is the pneumogastric nerve. 

The sympathetic nerve lies deeper in the fascia toward its posterior surface and 
is not so likely to be wounded. Its superior cervical ganglion lies opposite the 



APPLIED ANATOMY. 

second and third vertebrae. Working still higher, the transverse process oi tf^ 
atlas or first cervical vertebra will be felt and seen below and to the inner side of the 
mastoid process. The connective tissue adherent to the nodes is attached to this 
transverse process and may have to be cut loose or scraped away. In doing so 
keep to the outer edge because the jugular vein and internal carotid artery lie on its 
anterior surface. 

Beneath the sternomastoid runs the anterior scalene muscle and on it, coming 
from the third, fourth, and fifth cervical nerves, is the phrenic nerve; so that it is 
not permitted to dig into and disturb the muscular mass to the outer side of the 
common carotid artery on which these nodes frequently lie. 

In operating in the submental regio7i there is nothing to fear. The space 
between the two anterior bellies of the digastric muscles on the sides, the hyoid 
bone below, and down to the anterior surface of the mylohyoid muscle beneath, can 
be cleared out with impunity. 




N. occipitalis major 
Art. occipitalis 

Complexus 

Sternomastoid 

Splenius 

Levato"- scapulae 



Trapezius 

Complexus 

Obliquus superior 

Splenius 

Trachelomastoid 

Art. occipitalis 

Transverse process, atlas 

Art. vertebralis 

Rectus capitis posticus major 

Rectus capitis posticus minor 

Obliquus inferior 

Levator scapulae 

Complexus 

Splenius 




Rhomboideus 
minor 



Rhomboideus 
major 



Fig. 182. — Superficial and deep structures of the back of the neck, showing the suboccipital triangle, 
formed by the rectus capitis posticus major, obliquus superior and obliquus inferior: the suboccipital nerve 
emerges from just beneath the art. vertebralis. 

In the submaxillary region remember that the fascia covering the submaxillary 
gland is thin, so that the gland will probably be exposed as soon as the superficial 
structures are raised. As the facial artery and vein cross the mandible just in front 
of the masseter muscle, the vein is posterior. The artery goes under the gland and 
is adherent to it, so that as the gland is raised the artery is brought up also. The 
facial and lingual veins usually empty into the internal jugular, but, as shown in Fig. 
168, they may receive a communicating branch from the external jugular and the 
anterior jugular and continue down as the anterior jugular to empty into the 
external jugular low down in the neck, beneath the sternomastoid muscle. The 
hypoglossal nerve will be seen lying on the hyoglossus muscle, but it is readily 
avoided. The lingual artery is beneath the hyoglossus muscle anteriorly but both it 
and the facial must be looked for as one nears the posterior belly of the digastric. 

In the lower cervical region, opposite the cricoid cartilage, the omohyoid muscle 
will be met. It will sometimes be necessary to divide it. The sternohyoid and sterno- 
thyroid muscles and the thyroid gland are to be drawn inward and the sternomastoid 
outward. One should always keep away from the thyroid gland, as the recurrent 



THE NECK. i6i 

laryngeal nerve runs behind it and on the oesophagus near the trachea. Cutting it 
will probably cause a permanent alteration in the voice. If the internal jugular vein 
has been removed, as it may be on one side, but not on both, beneath it one is 
liable to encounter the inferior thyroid artery below Chassaignac's tubercle on the 
sixth cervical vertebra, and further out the phrenic nerve on the scalenus anticus mus- 
cle, and lower down the transverse cervical and suprascapular arteries. The inferior 
thyroid veins usually run downward to empty into the innominate veins, but the 
lower portion of the anterior jugular vein and the middle thyroid veins will probably 
have to be ligated. The course of the various veins is quite irregular and large 
venous branches may be encountered at any place. 

In the posterior cervical triangle the spinal accessory nerve must be avoided as 
it runs down and back from the middle of the posterior edge of the sternomastoid 
muscle. The external jugular, posterior jugular, transverse cervical, and supra- 
scapular veins may all require ligation. Beneath the deep fascia (superficial layer) 
are the descending or supraclavicular branches of the cervical plexus from the third 
and fourth cervical nerves. Care should be taken not to mistake them for the 
spinal accessory nerve. If the nerve has been divided it should be sutured together 
again at the completion of the operation. It is hardly necessary to caution against 
wounding the subclavian vein; it is in front of the anterior scalene muscle. The 
artery is behind the muscle. Do not dig under it. It rests on the pleura, a wound or 
tear of which may mean a septic pleurisy and death. In the angle formed by the 
junction of the internal jugular vein and subclavian on the left side is the thoracic 
duct. If wounded death may ensue through persistent leakage of lymph, but not 
infrequently healing eventually occurs. Wounding of the corresponding lymphatic 
duct on the right side is not considered so serious, the chyle being carried by the left 
duct. The cords of the brachial plexus run down and across the posterior cervical 
triangle above the subclavian artery, but a little care will enable one to avoid them. 
This is one of the regions of the body in which exact surgery is essential. 

OPERATIONS ON THE AIR-PASSAGES. 

The pharynx may be opened just below the hyoid bone, — subhyoidean pharym- 
gotomy. The larynx may be opened in the median line, — thyrotomy. The crico- 
thyroid membrane may be opened, — laryngotomy. The trachea may be opened, — 
tracheotoyny. 

Subhyoidean pharyngotomy is the entering of the pharynx by means of an 
incision below the hyoid bone. This is an extremely rare operation. It may be 
performed for the removal of foreign bodies or tumors. The incision may be made 
just below the hyoid bone and parallel to its border. This will divide the com- 
mencement of the anterior jugular vein, perhaps near the median line, perhaps toward 
the side. A transverse vein usually runs from one anterior jugular vein to the other 
across the median line at this point. Attached to the hyoid bone nearest to the 
median line is the sternohyoid muscle, then farther out the omohyoid, and still farther 
out the thyrohyoid. A small artery, the thyrohyoid, a branch of the superior thyroid, 
or sometimes of the lingual, will be divided. 

The thyrohyoid membrane being incised, access is obtained to the fatty tissue 
at the base of the epiglottis. If the incision is carried directly backward the epiglottis 
will be cut through at its base. If, however, it is kept close to the hyoid bone and 
made upward, the pharynx will be entered in front of the epiglottis and at the 
root of the tongue. If the incision is carried too far toward the sides the superior 
thyroid artery and even the external carotid itself will be cut; if carried too low down 
on the thyrohyoid membrane, then the superior laryngeal artery and nerve may both 
be wounded. Attention has already been called to the thyrohyoid branch. 

Thyrotomy is the division of the thyroid cartilage in the median line. The 
sternohyoid muscles almost touch in the median line. The division should be 
exactly in the median line. This will avoid wounding the anterior jugular veins. If 
not in the median line the incision will wound one of the vocal cords. Impairment 
of the voice certainly follows this operation; it is only performed for the removal of 
foreign bodies or growths. 



l62 



APPLIED AN ATOM \^. 



Laryngotomy is the opening of the cricothyroid membrane. It is rarely 
done, but it is of service in cases of choking from obstruction of the larynx, foreign 
bodies, etc. 

There is not sufficient room between the cricoid and thyroid cartilages to do 
this operation properly until puberty has been reached and the larynx has enlarged. 
The cricoid cartilage is narrow in front but wide behind. Its upper edge rises rapidly 
as it passes backward, forming an upper crescentic border, the concavity being 
upward. The lower edge of the thyroid is concave downward. Thus the two edges 
make an oval opening in front which in children is too small to hold the tracheotomy 
tube. The nearness to the vocal cords is also a serious objection. Performing a 
laryngotomy is the easiest and quickest way to enter the air-passages. Both the 
thyroid and cricoid cartilages in the median line are practically subcutaneous. A lon- 
gitudinal incision of the skin is usually advised, after which a transverse incision is em- 
ployed for opening the cricothyroid membrane. The tube is to be shorter than the one 
ordinarily used for tracheotomy. The cricothyroid artery, running across the mem- 
brane, is usually too insignificant to cause any trouble ; it is nearer the thyroid cartilage, 
therefore the cut through the membrane should be close to the cricoid cartilage. 

Tracheotomy is the opening of the trachea. There are two varieties, the 
high and the low, according as the tube is inserted above or below the isthmus of 
the thyroid gland. When in the adult male the neck is in line with the axis of the 
body the lower border of the cricoid cartilage is about 4 cm. (ij4 in.) above the 
sternum. When the head is tilted far back the larynx is drawn upward and the 
lower border of the cricoid is 6 cm. (about 2}^ in.) above the sternum. Hence in 
doing a tracheotomy the head is to be tilted far back. The total length of the 
trachea is 10 to 12 cm. (Morris, Hensman), beginning opposite the sixth cervical 
vertebra, — upper border in the child and lower in adults, — and ending opposite the 
fifth dorsal. About half of it is above and half below the top of the sternum. It is 
composed of 14 to 20 rings. In the adult the isthmus of the thyroid gland covers 
the second, third, and fourth rings. There are about eight rings above the sternum. 

According to Symington and Guersant (Treves) the diameter of the trachea is 
about as follows: 



1)4 io 2 years 5 mm- 

2 to 4 years 6 mm. 

4 to 8 years 8 mm. 

8 to 12 years 10 mm. 

12 to 15 years 12 mm. 

Adults 12-15 mm. 

A knowledge of the size of the trachea is necessary in order to select a trache- 
otomy tube of a size suitable to the particular case. The liability is to select too 
large a tube for young children, particularly infants. If this is done it may be very 
difficult to introduce the tube, or the trachea may even be torn in the attempt. In 
operating, an incision 2. 5 to 3 cm. long is to be made in the median line. This 
may cut the anterior jugular vein. If carried near to the sternum it will certainly 
divide the communicating branch between the anterior jugulars at that point. The 
top of the incision in a child will be over the cricoid cartilage, and as soon as the skin 
has been divided the finger is to be inserted and the cricoid cartilage felt and recog- 
nized. This will show how deep the trachea lies. In very young children the 
isthmus of the thyroid gland is liable to come up to the cricoid cartilage and the dif- 
ficulty of displacing it far enough down to allow the tube to be inserted is such that 
it may be best to divide it. Therefore after the skin and deep fascia have been divided 
and the cricoid recognized by the finger the soft tissues covering the trachea imme- 
diately below the cricoid are grasped on each side with a haemostatic forceps and 
divided between them. These tissues may embrace the isthmus of the thyroid gland, 
the edges of the sternohyoid muscles, some veins, branches from the superior and 
inferior thyroids, and the fascia covering the gland and overlying the trachea. 

The trachea should be cleared before opening it. A sharp hook is inserted into 
the cricoid cartilage to steady it and an incision is made into the trachea from below 
upward. In making this incision the utmost care must be taken not to cut through 



THE NECK. 



163 



the trachea and wound the oesophagus behind. The trachea of a child is not the hard 
resisting structure of the adult. It is a soft tender tube easily compressed and readily 
torn by roughness, or punctured with a knife. Forceps do not readily hold in it and 
stitches through it are liable to tear out. Only the very tip of the point of the knife 
should be allowed to enter the tube. The utmost care must be taken to keep in the 
median line. This is to be accomplished by using the cricoid cartilage as a guide 
and by seeing that the position of the head is straight. Cutting to either side of the 
trachea will cause wounding of the common carotid arteries. Below the isthmus of the 
thyroid gland and running down on the trachea are the inferior thyroid veins. The 
superior and middle thyroid veins empty into the internal jugular vein, but the 
inferior thyroids go downward to empty into the innominate. These veins will be cut 
if a low tracheotomy is done. In the infant the innominate artery and sometimes, 
though rarely, the left carotid encroach on the suprasternal notch and may be wounded 
if the incision is carried too low. The left innominate vein as it crosses to the 



Lingual and facial veins 



Interna] jugular vein 



Middle thyroid veins 



Sternohyoid muscle 
Sternomastoid muscle 
Sternothyroid muscle 
Anterior jugular vein 
Inferior thyroid vein 




drawn back 



— Hyoid bone 

Thyroid cartilage 

Cricothyroid muscle 

Sternohyoid muscle 

Sternothyroid muscle 

Superior thyroid artery and vein 

Cricoid cartilage 
_ Thyroid gland 
^ Inferior thyroid artery 



Inferior thyroid vein 

Sternomastoid muscle 

Trachea 

Communicating branch between the 

anterior jugular veins 



Fig. 183. — Dissection showing the parts involved in operations on the thyroid gland and air-passages. 

right side is liable, especially in very young children, to show quite plainly above the 
sternum and would certainly be cut if the deep incision was carried as far down as 
the top of the sternum. An anomalous artery, the thyroidea ima, a branch of the 
innominate, sometimes passes upward on the trachea. On account of the presence 
of all these vessels it is not allowable to do any cutting of the deep parts just above 
the sternum; they are simply to be depressed by blunt dissection and kept out of 
the way with retractors while the trachea is being incised. The cricoid cartilage is 
never to be incised. It is far more firm and resistant than the trachea and it serves 
to keep the trachea from collapsing. The proximity of the tracheotomy tube to the 
vocal cords would result in interference with their function. 

The method of Bose consists in dividing the fascia OA^erlying the trachea near 
the cricoid cartilage and pushing it down, carrying the isthmus and veins with it, 
and introducing the tube into the space so cleared. This is so difficult that it is 
better to divide the isthmus, as already described. 



OPERATIONS ON THE THYROID GLAND. 

The operations which are done on the thyroid gland are ligation of its arterial 
supply and complete or partial removal. These necessitate a knowledge particularly 
of its blood supply and structure. 

The thyroid gland cov&v&Vs, of an isth?mis and two lateral lobes. The isthmus 



164 



APPLIED ANATOMY. 



crosses the second, third, and fourth tracheal rings in the adult. In children it may' 
approach nearer to the cricoid cartilage. 

The lateral lobes lie under the sternohyoid and the sternothyroid muscles. 
They rise as high as the oblique line on the sides of the thyroid cartilages which 
marks the insertion of the sternothyroid muscles. The lobes descend to the level 
of the sixth ring of the trachea, which is two rings below the isthmus, about two 
centimetres above the sternum. The inferior constrictor of the pharynx is beneath 
the gland. The thyroid gland is covered by the pretracheal fascia and possesses 
a capsule of its own besides. This fascia envelops the gland and its capsule, and 
from its posterior surface is prolonged down on the trachea and envelopes the 



Omohyoid muscle 
Sternothyroid muscle 

Sternohyoid muscle 



Sup. parathyroid 

Inf. parathyroid 
Trachea 
Sternothyroid muscle 




Stemomas- 
toid muscle 



CEsophagus 
Omohyoid muscle 

Inferior thyroid artery 

Recurrent laryngeal nerve 
Middle thyroid vein 
Inferior thyroid veins 

Sternohyoid muscle 



Fig. 184. — Excision of the thyroid gland. 



vessels coming to and leaving the gland. Therefore we might say that the inferior 
thyroid veins are in the pretracheal fascia. 

As the fascia leaves the gland at the sides one portion of it blends with and 
helps to form the sheath of the vessels. The other or deeper portion continues 
around the pharynx and oesophagus, forming the buccopharyngeal fascia. In freeing 
the gland and its capsule from the overlying pretracheal fascia care must be taken, 
as pointed out by James Berry (" Diseases of the Thyroid Gland," p. 269), not to 
be led by this fascia too far posteriorly and therefore wound, as has been done, the 
pharynx or trachea. 

The veins of the gland are more prominent and dangerous than the arteries. 
They ramify beneath the capsule and as long as the capsule is not torn the bleeding 
is slight. The arteries of the thyroid gland are the superior and inferior thyroids 
and sometimes the thyroidea ima. The superior thyroid comes off the external 



THE NECK. 165 

carotid just above the bifurcation. It rises almost to the greater horn of the hyoid 
bone and then descends to the thyroid gland, which reaches to the level of the oblique 
line on the thyroid cartilage; it supplies the upper portion of the gland, particularly 
the anterior portion, but also sends a branch down the posterior surface. The 
vessels crossing the median line, contrary to what is often the case in the arteries of 
the lip and even the scalp, are very small. The superior thyroid is superficial and 
presents no special difhculty in ligation. The vein runs beneath it on its course to 
the internal jugular. The inferior thyroid artery, a branch of the thyroid axis, 
crosses behind the common carotid artery about the level of the seventh cervical 
vertebra, about on a line with the lower edge of the isthmus. It enters the gland 
from the side and not from below and ramifies on its posterior surface often as a 
single large trunk beneath the capsule giving off branches to the parenchyma. 
Usually it is in front of the recurrent laryngeal nerve, but the middle cervical gan- 
glion of the sympathetic lies on it. Sometimes the artery breaks into branches before 
it enters the gland. In such cases the recurrent laryngeal nerve may run between 
these branches and so be injured in removing the gland. 

The thvroidca ima artery when present enters the gland from below, coming up 
on the trachea usually from the innominate, in which case the innominate is apt to 
come of? more to the left side and so bring the common carotid closer to the trachea 
than usual. It may also spring from the aorta or from the right carotid artery. 

The Veins. — There are three sets of veins, a superior, a middle, and an inferior 
thyroid, and, as Kocher has pointed out, an accessory thyroid between the middle 
and inferior ones. The veins ramify under the capsule and form a plexus, which 
in goitre is much enlarged and communicates freely across the median line at the 
upper and lower portions of the isthmus. The superior and middle thyroids pass 
outward to empty into the internal jugular. Still lower is the accessory inferior thy- 
roid, which may empty into the internal jugular, as do the two above it, or it may pass 
down, as does the inferior thyroid vein, and empty into the innominate. The inferior 
thyroid vein does not follow the artery of the same name but with its fellow of the 
opposite side passes directly downward in front of the trachea to empty into the 
innominate vein. Its importance in operations on the trachea has already been alluded 
to in speaking of tracheotomy. 

In removing the gland the superior thyroid artery is found at the upper outer 
angle, the ligature should be placed sufficiently far out to include the branch to the 
posterior surface of the gland. In ligating the inferior thyroid arteries they are to 
be sought at the lower portion of the sides of the gland and are to be ligated either 
close to the gland or isolated by pulling the carotid artery outward, and tied as they 
make the bend at the edge of the anterior scalene muscle. Between these two 
points lies the recurrent laryngeal nerve, usually behind the artery. Halsted advises 
that each separate branch be ligated as it enters the gland to avoid those supplying 
the parathyroids. The gland is covered by the omohyoid, sternohyoid, and sterno- 
thyroid muscles. If these cannot be drawn aside they should be divided near their 
upper ends in the same manner as already advised in the case of division of the 
sternomastoid in removing tuberculous nodes. The sternomastoid muscle will have 
to be drawn outward. 

The internal jugular vein often overlaps the common carotid artery, reaching 
sometimes even to its inner side, so that the position of the artery is not a sure guide 
to the location of this vein. 

When a goitre dips behind the sternum the presence of the left innominate 
vein should not be forgotten. 

THE PARATHYROID BODIES. 

The parathyroid bodies are usually four in number, but rarely there may be five 
or six. They are 6 to 7 mm. long, 3 to 4 mm. broad, and 1.5 to 2 mm. thick. The 
most constant site of the superior parathyroid is at the middle or junction of the upper 
and middle thirds of the posterior edge of the thyroid gland opposite the cricoid carti- 
lage. The lower parathyroid is near the lower pole, but may be below it. They are 
small brownish bodies in the meshes of the loose connective tissue forming the outer 
capsule of the gland. Often they are quite distinct from the gland, but sometimes 



i66 



APPLIED ANATOMY. 



they lie in a cleft in the gland and thereby escape recognition. They possess a separate" 
capsule. They are supplied by a separate artery, the parathyroid, a branch of the 
inferior thyroid. This latter usually gives off two parathyroid arteries, one to each 
body. Ginsburg {Univ. Pe?ma. Med. Bulletin, Jan., 1908) has demonstrated a free 
anastomosis with the vessels of the opposite side. In many cases it is practically 
impossible to avoid wounding or removing the parathyroids in operations — Halsted 
has suggested three means of avoiding their removal, viz. : ( r ) slice of? and leave the 
piece of thyroid gland supposed to contain the parathyroids; (2) ligate the superior 




Inferior constrictor 
Superior thyroid artery 

Cricothyroid muscle 
Superior parathyroid 
Inferior thyroid artery 

Thyroid gland 

Inferior parathyroid 

CEsophagus 

Recurrent laryngeal nerve 

Trachea 



Fig. 185. — Showing the parathyroid bodies. 

and inferior thyroids, and a week or two later perform a subcapsular enucleation of the 
thyroid; (3) search for each parathyroid by following out the ramifications of the 
inferior thyroid artery — this is the best method of finding them in post-mortem 
examinations. 

CESOPHAGUS— CERVICAL PORTION. 

The oesophagus runs from the level of the cricoid cartilage to the stomach. 
The cricoid is opposite the sixth cervical vertebra and the cardiac or oesophageal end 
of the stomach is opposite the lower border of the tenth thoracic vertebra. It is in the 
median line above, then curves slightly to the left until the root of the neck is 
reached, when it returns to the median line opposite the fifth thoracic vertebra. 

It is in front of the spine and the prevertebral fascia. The layer of fascia between 
its anterior surface and the trachea is extremely thin. On each side are the common 
carotid arteries and the sheath of the vessels. The right recurrent laryngeal nerve 
winds around the commencement of the first portion of the subclavian, and passes 



THE NECK. 



167 



inward and upward behind the common carotid artery to reach the groove between 
the trachea and oesophagus in which it ascends to the larynx. 

On the left side the recurrent laryngeal nerve winds around the arch of the aorta 
and ascends in the groove on the left side between the trachea and oesophagus. The 
left carotid artery is closer to the oesophagus than the right. The narrowest point of 
the lumen is at the cricoid cartilage. Its next narrow point is where it crosses the aorta 
and left bronchus. This is opposite the upper part of the second piece of the sternum 
or the upper border of the fifth thoracic vertebra. The third narrow portion is the 
cardiac opening into the stomach. Mouton (Tillaux, "Anat. Topograph.," p. 418) 
gives the diameter of the oesophagus at each of these three points as 14 mm. 

Foreign Bodies. — Foreign bodies if they pass the cricoid cartilage are most 
liable to stop at the aorta and the left bronchus. This is opposite the angle of Ludwig 



Left common 
carotid artery 

Vagus nerve 

Internal jugular 
vein' 

Inferior thyroid 
artery 

Vertebral artery 

Thoracic duct 

Phrenic nerve 
Recurrent laryn- 
geal nerve 
Subclavian 
artery ' 
Bronchial artery 

Pulmonary artery 

Left vagus nerve7 




Internal jugular 
vein 

Vagus nerve 
Common carotid 
artery 

Inf. thyroid artery 
■Vertebral artery 
Trachea 

Recurrent laryn- 
geal nerve 
CEsophagus 
Vagus nerve 
Phrenic nerve 
Vena azygos 
major 
■Right bronchus 

Right pulmonary 
artery 

Pulmonary vein 



Fig. 186. — Relations of the cervical portion of the oesophagus, viewed posteriorly. 

and the second rib, so that the foreign body is either at the root of the neck or just 
below the top of the sternum. If it passes the two upper constrictions it will prob- 
ably pass the third, because the cardiac constriction is caused by the diaphragm, which 
relaxes and allows the body to enter the stomach. 

CEsophagotomy. — In operating, an incision is made along the anterior border 
of the left sternomastoid muscle from the sternoclavicular joint upward. The anterior 
jugular vein will be cut. After opening the deep fascia the sternomastoid is to be 
pulled outward. The omohyoid is to be drawn up and out and also the lower por- 
tion of the sternohyoid and perhaps the sternothyroid. 

The middle thyroid and perhaps an accessory thyroid vein are divided and the 
thyroid gland and trachea drawn inward. The trachea is to be identified by the 
sense of touch. The inferior thyroid artery is behind the sheath of the vessels and is 
so high that it is not likely to be injured. The recurrent laryngeal nerve must be 
looked for between the oesophagus and trachea, and avoided. In going deep down 
care must be taken not to injure the innominate vein, which comes well up towards the 
top of the sternum. 



i68 



APPLIED ANATOMY. 



CUT THROAT. 

The most frequent site of the incision in cases of cut throat is between the hyoid ' 
bone and thyroid cartilage. If above the hyoid bone, the incision will divide the 
mylohyoid, geniohyoid, geniohyoglossus, and hyoglossus muscles, and perhaps the 
digastric and stylohyoid. If it goes far back it may wound the submaxillary gland 
or duct, the facial or lingual arteries and veins, and the hypoglossal nerve. The 
commencement of the anterior jugular will certainly be divided and the external 
jugular may also be wounded. The cut passes through the base of the tongue and the 
upper portion of the epiglottis. The tip of the epiglottis is sometimes entirely cut of?. 
If in the thyrohyoid space, the incision passes a short distance above the vocal cords. 
The sternohyoid, omohyoid, and thyrohyoid muscles are divided. If prolonged 
backward the pharynx will be opened and perhaps the arytenoid cartilages wounded. 
The superior thyroid artery is Hkely to be cut. This is the vessel most often divided 
in suicidal wounds. The carotid arteries and internal jugular veins are deep and far 
back, lying under the edge of the sternomastoid muscle, and are rarely wounded. 



Sternohyoid muscle 



Sternothyroid muscle 



Thyroid gland 



Recurrent laryn- 
geal nerve 




Omohyoid muscle 

, Inferior thyroid artery 
Common carotid artery 

Sternomastoid muscle 



(Esophagus 



Exposing the resophagus. 



If these are cut, death usually rapidly ensues from hemorrhage. The superior 
laryngeal nerve may be injured as it pierces the thyrohyoid membrane. This nerve 
is sensory and its division is followed by anaesthesia of that half of the larynx to 
which it is distributed. This favors the entrance of food and liquids into the larynx 
and so may cause a fatal septic pneumonia. If through the thyroid cartilage the 
incision may wound the vocal cords. They lie just beneath the most prominent 
part of the thyroid cartilage and just below its median notch. If through the trachea, 
the incision may wound the thyroid gland, which reaches from about the sixth ring 
of the trachea to the oblique line on the thyroid cartilage. 

Bleeding from the wounded thyroid, if the gland is normal in size, is not likely 
to be excessive. Below the cricoid cartilage the oesophagus may be wounded, above 
it the pharynx may be opened. The two large sternomastoid muscles being put on 
the stretch tend to protect the large vessels beneath. Suppuration not infrequently 
accompanies these wounds of the neck in which the air and food passages are in- 
volved and may give rise to collections of pus which may travel between the fascias, as 
previously described. In treatment it is customary to cleanse the wounds and approxi- 
mate the various injured tissues as carefully as possible, and feed by a stomach tube. 



THE NECK. 



169 



AFFECTIONS OF THE NECK. 

Cervical Cysts and Fistulae. — The neck is the seat of some very peculiar 
cystic tumors and fistulae which are connected with developmental defects. They 




first arch 



Fig. 188. — Foetus, 2Sth day (after His). Showing branchial (visceral) arches and clefts or furrows. 



are either lateral or median in location. The lateral originate from the visceral 
(branchial) clefts, while the median are connected with the thyroglossal duct. The 
visceral clefts are depressions between the visceral arches. These arches, five in 
number, spring forward from each side of the embryo to form the neck region. 
Sometimes these arches are called branchial arches from the fact of their going to 
form the branchiae or gills of fishes and 
some of the other lower orders of animals. 

The first visceral arch di\'ides into 
two parts, a maxillary part forming the 
upper jaw and a mandibular part form- 
ing the lower jaw. Defects in the max- 
illary arch producing harelip and cleft 
palate have already been described. 
Two of the ear bones, the incus and 
malleus, are also formed by the mandib- 
ular portion of the first visceral arch. 

The second visceral arch forms the 
stapes, the styloid process, the stylo- 
hyoid ligament, and the lesser horn of 
the hyoid bone. 

The third visceral arch becomes the 
body and greater horn of the hyoid bone. 

Thefotaih snid fifth visceral arches 
blend and form the soft structures of the 
side of the neck. 

The first visceral cleft, called the 
hyomandibular cleft from its being be- 
tween the hyoid bone and the mandible, 
forms the middle ear and Eustachian 

tubes from its inner portion and the external auditory meatus from its outer portion. 
The membrana tympani is the remains of the membrane which stretched across from 
one arch to the other. Cervical fistulae are formed by the persistence of a visceral 
cleft. As the first visceral cleft persists normally in the structures already named, it 




Fig. 189. — Points of opening of sinuses originating 
from the thyroglossal duct and branchial clefts. (Modi- 
fied from Sutton.) 



170 



APPLIED ANATOMY. 



in itself does not form pathological fistulae, but congenital fistulae are sometimes 
encountered in the external ear which are the remains of the clefts between the 
tubercles of which the ear is formed. 

Cervical fistulae or sinuses may extend either completely through, from the 
surface to the pharynx, or may open internally or externally, or be closed at both 
ends, in which last case the contents accumulate and form a cervical cyst. 

FistulcE arising from the second visceral cleft open externally opposite the thyro- 
hyoid space in front of the s'ternomastoid muscle. Internally they open into the 
recess holding the tonsil. 

Fistula arising from the third and fourth visceral clefts open externally lower 
down nearer the sternoclavicular articulation in front of the sternomastoid muscle and 

internally in the sinus pyriformis. The 
persistence of the third and fourth 
visceral clefts internally may produce 
pharyngeal diverticula, as already 
noted in discussing that region. 

In attempting the cure of cysts 
and fistulae due to persistence of the 




Thyroglossal duct 



Median cervical, 
pouch or cyst 





Fig. 190. — Median cervical pouch or cyst arising from the 
thyroglossal duct. — Marshall's case. 



Fig. 191. — Median cervical (thyroglossal) 
cyst. — Author's case. 



visceral clefts it is evident that as they are lined with a secreting epithelium this must 
be destroyed or removed, or a recurrence will take place. In attempting to dissect 
them out one must be prepared to follow them through the structures of the neck 
to the pharynx inside. It is needless to say this may be a serious procedure. 

Hueter (quoted by Sutton) followed one between the two carotid arteries into the 
pharynx. These cysts and fistulae may be noted at birth or may develop later in life. 

Hydrocele of the Neck. — There are other cystic tumors of the neck which 
are congenital, being noticed at birth, and which grow to a large size. They are 
often wide-spread, extending not only between the tissues of the neck below the 
deep fascia but even into the axilla. Their walls are thin, consisting sometimes only 
of a layer of lining epithelium and the surrounding tissues. On this account it is 
impossible to dissect them out. The use of injections and setons has been aban- 
doned as too dangerous. They rarely require treatment, as they tend to disappear 
spontaneously. Mr. J. Bland Sutton ascribes their origin first to congenitally dilated 
lymph-spaces; second 2iS> resembling the cervical air-sacs that exist in the howling 
monkeys; and third that possibly some of them may be related to a persistence of 
some portion of a branchial cleft. 

Median cervical fistulae and cysts originate in connection with the thyro- 
glossal duct. This, in the embryo, leads from the foramen caecum at the root of the 



THE THORAX. 171 

tongue through to the posterior surface of the hyoid bone and thence downward and 
forward to the isthmus of the thyroid gland. It begins to atrophy in the fifth week 
and is obHterated by the eighth. According to Sutton these cysts are never congen- 
ital but occur soon after birth or as late as the fourteenth year. They appear as 
rounded, cystic tumors just below the hyoid bone or over the thyroid cartilage. They 
either inflame and break of their own accord, discharging externally, or are opened by 
the surgeon and, contrary to what is the case in hydroceles of the neck, never tend to 
disappear, but a sinus remains. At times it almost heals, then the contents accumulate 
and a cyst forms, this again breaks and a sinus results as before. In attempting a cure 
by operation the sinus should be followed up behind the hyoid bone. In one case after 
two failures of attempted excision a cure was obtained by destroying the tract by 
introducing a small gahanocautery point. Unless every portion of the lining mem- 
brane be completely destroyed the cells will go on secreting and reproduce, in a 
short time, the original condition. Failure to cure these sinuses and cysts by excision 
often occurs, notwithstanding the exercise of the greatest care. 

The lower portion of the thyroglossal duct may persist in the form of the pyramid 
or third lobe of the thyroid gland, which arises from the isthmus or from the left side 
and ascends as far as the hyoid bone, to which it is attached. 

THE THORAX. 

The thorax or chest is that portion of the trunk which lies between the neck 
and the abdomen. It is composed of a bony framework reinforced by soft parts, 
and contains the main organs of circulation and respiration. The oesophagus, an 
organ of the digestive tract, simply passes through it to the regions below. The 
chest-walls as well as the parts contained within them are affected by wounds and 
disease, especially the heart and its associated great vessels, and the lungs and 
pleurae. These organs are essential to life, like the brain and spinal cord, and like 
them, are encased in a bony framework. It is an example of bones performing a 
protecting function in addition to a supporting one. 

The functions of the heart and lungs are influenced by constitutional diseases in 
addition to their own local affections, hence they serve as guides to the general bodily 
condition, and the condition of the respiration and circulation is continually being exam- 
ined for the purposes of diagnosis, prognosis, and treatment, even when the heart and 
lungs themselves are not involved. To make these examinations intelligently, neces- 
sitates a knowledge of the organs themselves and their relation to one another and the 
surrounding parts. This is essential for the physician even more than the surgeon. 

The chest- walls are composed of a bony framework joined and bound together 
and covered by soft parts. 

The bones of the chest consist of the stermim, ribs, and thoracic vertebrce. The 
clavicle and scapula compose the shoulder-girdle and belong to the upper extremity. 
The human skeleton is divided into an axial portion and an appendicular portion. The 
axial portion embraces the skull, the vertebral column, including the sacrum and 
coccyx, the hyoid bone, the sternum, and the ribs. The appendicular portion con- 
sists of the shoulder-girdles and upper extremities and the pelvic girdles and lower 
extremities. 

The bony chest is subject to disease and injury as well as to defects in develop- 
ment, and to deformities due to these causes. 

Shape of the Chest. — The chest is conical in shape, being small above and 
large below. In transverse section it is kidney-shaped, the hilus of the kidney being 
represented by the vertebrae. In the foetus the anteroposterior diameter is greater 
than the transverse, thus resembling the thorax in the lower animals. After "birth 
and in infancy the two diameters are nearly equal, hence we have the rounded chest 
of the child. As growth and development progress the transverse diameter increases 
more than the anteroposterior, so that at about the second year the chest has become 
oval and in adults the transverse diameter is one-fourth greater than is the antero- 
posterior. 

Variations in the shape of the chest are mainly the result of disease. In child- 
hood, rachitic disease (rickets) produces a lateral flattening and a projection of the 



172 



APPLIED ANATOMY. 



sternum. If the sternum projects markedly it constitutes what is known as pigeon 
breast, the chest in such a condition being- longer from before backward than from side 
to side. In this disease also there may be a depression on each side of the sternum, 



Clavicular articulation 
Manubrium 




Angulus stemi or 
angle of Ludwig 



Body or gladiolus 



•Xiphostemal articulation 

Xiphoid or ensiform 
cartilage 



\,% 



Fig. 192. — The bony thorax. 

the back is rounded owing to the bending of the vertebral column, and the points of 
junction of the ribs and cartilages are enlarged, this latter constituting what is known 

as beading of the ribs. These beads are 

felt as rounded enlargements at the sternal 

extremities of the ribs and form a line 

parallel to the sternum above and sloping 

outward below. This line of beads has 

been called the '' rachitic rosary.'' From 

the level of the ensiform cartilage a groove 

passes out toward the sides ; this has 

been called '' Harrison' s groove" (see 

Fig. 193). Sometimes the lower end of 

^j|L, •^ &-^^^"^^^^^^B ^^^^ sternum is pressed inward, forming a 

^BK^BT ^^^^K deep funnel-shaped depression constituting 

^^^If ^^^1 the deformity known as "" fimnel chest" 

or the '' Trichterbrust" of the Germans. 
This condition of the chest, with the 
exception of the beading, is also produced 
in children by obstruction to the breathing 
from enlargement of the tonsils, from the 
presence of adenoid growths in the pharynx, 
and from hypertrophy of the turbinate 
bones, all of which interfere particularly 
with nasal respiration. 

Diseases of the lungs and pleurae alter 
the shape of the chest. In emphysema and 
when distended by plural effusions, the 
thorax becomes more rounded in shape, 
forming what is called the ' ' barrel-shaped 
chest." In phthisis the wasting of the tissues and contraction of the lungs causes the 
chest to collapse. The ribs slope more sharply downward and the chest becomes 



xH 




Fig 



-Child showing Harrison's groove opposite 
the ensiform cartilage. 



THE THORAX. 



173 



longer and flatter, the anteroposterior diameter being diminished. The angle made 
by the lower ribs as they ascend to the sternum is called the costal angle ; this 
becomes decreased in phthisis. This form of chest is known as the ' 'phthisical chest. 





/ 




Fig. 195. — Flat chest of phthisis. 



Fig. 194. — Barrel chest of emphysema. 

When the flatness is marked it is sometimes called the ' ''flat chest. ' ' When the scapulae 
project like wings it is called ^'alar'' or ''pterygoid chest.' ^ 

In Pott's disease, or caries of the spine, as the kyphosis develops the chest falls for- 






PiG. 196. — Kyphosis from Pott's disease, or caries 
of the lower thoracic vertebrse. The curvature is an 
angular anteroposterior one. 



Fig. 197. — Scoliosis, or lateral curvature of the spine. 



ward and its anteroposterior diameter is increased. The abdominal contents are crowded 
up into the chest and push the sternum and lower ribs forward. Associated with this 
deformity is oftentimes a lateral deviation of the parts above the site of the disease. 



174 ^m^ APPLIED ANATOMY. ^SKKKB^I^m 

In scoliosis, or lateral curvature of the spine, the distortion is uneven, being a 
compression of the thorax from above downward and a twisting around a vertical 
axis. The deformity is frequently so severe as to cause the lower ribs to rest on the 
iliac crests. It is in order to detect these diseases in their early stages that a know- 
ledge of the shape of the normal chest is so essential. 

THE STERNUM. "I 

The sternum consists of three pieces: the niamibrium ox presternum, gladiolus 
or nicsosteruutn, and xiphoid cartilage or metaster^ium. It is developed in two 
lateral halves. Should these fail to unite an opening is left in the bone through which 
the pulsations of the heart have been seen and felt. The junction of the first and 
second pieces of the sternum is opposite the second rib. The se\enth is the last rib 
to articulate with the sternum directly. 

The first and second pieces of the sternum are connected by a joint which per- 
sists to advanced age. The projection caused by this joint is called the angulus sterni 
or angle of Ludwig. Fractures pass either through this joint, opposite the second 
rib, or through the bone just below it. They are produced by both direct and 
indirect force. Usually the upper fragment is beneath the lower one. It is however 
more true to state that the lower fragment is displaced anteriorly. Any marked pos- 
terior displacement of the upper fragment would tend to press on the trachea and in- 
terfere with breathing; the trachea bifurcates opposite the joint. As the pleurae and 
lungs of the two sides almost or quite touch behind the second piece of the sternum, 
they may be wounded and emphysema may occur. The heart also maybe wounded. 
Suppuration has followed these injuries, in which case it will be necessary to trephine 
the sternum to give exit to the pus. The necessity of avoiding wounding of the 
pleurae in such a procedure is evident, as it would be followed by collapse of the lung 
and empyema. 

THE RIBS AND COSTAL CARTILAGES. 

The ribs are frequently fractured, sometimes they become affected with caries, 
and in operating the chest is frequently opened between them or portions of them 
are excised. They are both elastic and movable, and difficult to break; hence frac- 
ture is almost always due to direct violence, and this violence may be so great as 
sometimes to cause death. Normally there are twelve ribs on each side, but some- 
times there is an extra cervical or lumbar rib. These are both rare, the latter the 
more so. 

The seven upper ribs are called true ribs because they articulate with the sternum. 
The remaining five are called y«/j'^ ribs, the eleventh and twelfth hitxw^ floating ribs. 
The eighth, ninth, and tenth ribs each articulate by their cartilages with the rib above. 
The tenth forms the lower margin of the thorax. The eleventh and twelfth ribs are 
attached only by their posterior extremities, their anterior portion being imbedded in 
the soft parts; hence they are called floating ribs. The ribs slope downward and 
forward. This obliquity increases until the ninth rib, after which it decreases. The 
first rib in front corresponds to the fourth behind, the second, third, fourth, fifth, 
sixth, and seventh in front correspond each to the fourth rib lower behind. The first 
rib is the nearest horizontal in regard to its surface and, being well protected by the 
clavicle, is rarely broken. The intercostal spaces are broader in front than behind 
and broader above than below. The third is the largest. 

The groove on the lower surface of the ribs holds the intercostal artery, but only 
as far back as the angle, from which point it occupies the middle of the space. 

The extent of the intercostal spaces is considerably influenced by position — flexion 
of the body brings the ribs together, extension and bending to the opposite side 
separates them. This point is of importance in reference to the operations of para- 
centesis and empyema. 

The first costal cartilage unites directly with the sternum, there being no joint 
present. The second and sometimes the third cartilage is joined to the sternum by 
a ligament with a synovial joint above and below it. The other costal cartilages are 



THE THORAX. 



175 



united by a joint with a single cavity. These joints may be the seat of metastatic 
abscesses in pyaemic infections. 

Cervical ribs spring from the body and transverse process of the seventh 
cervical vertebra. They may be long enough to reach to the sternum, but usually 
are much shorter. One case of this affection was seen by the writer in a man 
twenty-seven years of age. There was an abnormal fulness above the scapula 
posteriorly, and above the clavicle anteriorly, just to the inner side of the external 
jugular vein, a distinct bony process could be felt. This did not move with the 
scapula or clavicle but did move somewhat with respiration. A skiagraph showed 
it to be attached to the spine. The patient was seen again live years later, 




Fig. 198. — A cervical rib attached to the right side of the seventh cervical vertebra. 



when the same condition of affairs existed, with the exception that movement on 
respiration was not so marked. A knowledge of the possible presence of a cervical 
rib is important in diagnosis, otherwise it may be thought to be a bony or malignant 
new growth and treatment advised accordingly. The subclavian artery may pass 
over the cervical rib above and may have its circulation seriously interfered with. 

Fracture of the Ribs. — The ribs are almost always broken by direct violence; 
fractures from indirect force, as from coughing, sneezing, and other forms of muscular 
exertion, are rare. Fracture from compression of the chest is also rare. The site of 
the fracture is most frequentiy on the anterior portion of the chest and not the sides 




Fig. 199. — Fractured ribs; fusion of callus. 



or back. The fourth, fifth, sixth, and seventh ribs are most often broken. The first 
rib is well protected from direct blows by the clavicle. Lane, however, has shown 
that it can be broken by pressure of the clavicle when the shoulder is depressed. 
The eleventh and twelfth, being floating ribs, are rarely broken. The twelfth rib is 
the least frequently so. In one case we saw the eighth, ninth, tenth, eleventh, and 
twelfth all broken by the passage of a wheel. The soft parts attached to the frag- 
ments prevent much displacement, but there is always some, due to the respiratory 
movements. Hence callus is always present and it may be so abundant as to join 
adjacent ribs (see Fig. 199). As already stated, death frequently follows fracture of 
the ribs and is due to wounding of the chest contents. Rarely the intercostal arteries 
may be wounded and produce haemothorax. Wounding of the lung is frequent. 



176 T^S^B^ APPLIED ANATOMY. IMBJJffjiy: 'JJUfJ 

Emphysema of the surface of the body may ensue, but is not dangerous. Pneumo- 
thorax, which may be accompanied by infiltration of air into the lung tissue, is more 
dangerous, favoring collapse of the lung. The object of treatment is to keep the 
chest-walls from moving. This is accomplished by strapping the chest with adhesive 
plaster, which is usually laid on almost in the direction of the ribs ; but as the chest 
moves with respiration, the ribs rising, and as they slope downward and forward, I 
have preferred to lay the straps on from in front downward and backward, this tends 
to prevent the ribs from rising in inspiration. 

THE THORACIC VERTEBRA. m 

The thoracic or dorsal vertebrae are twelve in number and are so articulat^i 
with one another as to form a single, regular curve with its concavity forwards and 
convexity backward. Any sudden change in the direction of the curve is an evidence 
of disease; this is seen in the angular curvature of Pott's disease or caries of the 
spine. The ribs are connected with the vertebrae by the articulation of the head of 
the rib with the body of the vertebra, and the tubercle of the rib with the transverse 
process. The transverse process is connected with the body by the pedicle and with 
the spinous process by the lamina. The spinal cord is exposed in operations by 
removal of the spinous process and laminae, hence the name laminectomy. 

The spinous processes are the guides which indicate the position and condition 
of the vertebrae. Their tips are not covered by muscles but lie close beneath the 
skin and are readily felt and any abnormality detected. In the normal body the 
grooves on each side of the spinous processes are filled up with muscle, but in certain 
diseases, as in infantile paralysis and lateral curvature, they become atrophied and 
the spine becomes twisted, hence on the convex side of the abnormal lateral curve, 
to the outer side of the spines, the projection formed by the transverse processes and 
tubercles of the ribs can be both seen and felt. 

The external curve formed by the tips of the spinous processes of the thoracic 
region in the normal person is not so great as is the curve formed by the anterior 
portion of the bodies of the thoracic vertebrae. This is because the spinous 
processes at the upper and lower portions of the chest project out almost at right 
angles to the long axis of the body, while those of the middle portion slope down- 
ward. Hence the tips of the spinous processes of the seventh cervical, first dorsal, 
and twelfth dorsal vertebrae are opposite the bodies of the same vertebrae, while the 
others are opposite the bodies of the vertebrae next below. (The spine will be 
considered more at length in the section devoted to the Back. ) 

SOFT PARTS. 

The bony thorax is lined by the pleurae, the ribs are united to each other by 
the intercostal muscles, and over all are muscles, superficial fascia, and skin. In 
addition, in front are the mammary glands and behind are the scapulae. 

The Intercostal Muscles and Arteries. 

The intercostal spaces are occupied by the two intercostal muscles, with a fascia 
above them, one below, and one between them. 

The external intercostal muscles run downward and forward. They begin at 
the tubercles of the ribs posteriorly and end at the costal cartilages anteriorly. 
They are continued forward to the sternum by the anterior intercostal membrane, 
formed by the fusing of the outer and middle intercostal fascias. The internal 
intercostal muscles go downward and backward. They begin at the sternum and 
end at the angles of the ribs. They are continued to the spine by the posterior 
intercostal membrane, formed by the fusing of the middle and internal intercostal 
fascias. The intercostal arteries come from both anteriorly and posteriorly. The 
anterior intercostals come from the internal mammary for the upper five or six 
spaces and from the musculophrenic artery for the remainder. They arise either 
as a single trunk or as separate superior and inferior branches. At first they are 
between the pleura and internal intercostal muscle, but they soon perforate that 



THE THORAX. 



177 



muscle and run between it and the external intercostal, the superior branch running 
along the lower edge of the rib and the inferior branch running along the upper 
edge of the rib below. The aortic or posterior intercostal arises as a single trunk 
which passes between the external intercostal muscle and the pleura. Arriving op- 
posite the angle of the ribs it divides into superior and inferior branches which 
unite with those from the internal mammary {arteria inamviaria interna). 

From the vertebrae out to the angle of the ribs the intercostal artery lies about 
midway between the ribs, hence it is liable to be wounded in paracentesis if the 
puncture is made too far back. It is for this reason that operations for draining the 
pleurae are performed anterior to the costal angles. The superior intercostal 
branches are larger than the inferior ones. They run under the lower edge of the 
rib above the space and are therefore protected from injury, particularly stab-wounds. 

In opening the chest for empyema it is best to go about midway in the intercosal 
space and not too close to the lower edge of the rib on account of the liability of wound- 
ing the superior intercostal. The inferior branch is usually quite small and causes 
no serious hemorrhage. Intercostal bleeding may cause a hsemothorax if the wound is 



Anterior perfor- 
ating arteries 




Thoracic aorta 

Posterior intercostal arteries 



Anterior intercos- 
tal arteries 



Internal mammary arteries 

Fig. 200. — Course and distribution of the intercostal arteries. 

small. It may be controlled, if the vessel is cut in performing the operation of 
paracentesis for empyema, by clamping with haemostatic forceps. If these are 
allowed to remain on a few minutes the bleeding often does not recur on their 
removal. If desired a ligature can be applied. If it is undesirable to rely on the 
clamp or ligature then the wound may be hrmly packed with gauze or a piece of gauze 
may be depressed through the wound into the pleural cavity and then stuffed with 
more gauze, after which the tampon so formed is pulled firmly outward against the 
bleeding: tissues. 



MUSCLES. 

Covering the chest anteriorly are the pedoralis major and pedoralis minor 
Tnusclcs. The serrattis anterior {magnns) winds around its side and posteriorly, above 
is the trapezius and below the latissinuis dorsi. Beneath them are the erector spitice 
(^sacro spinalis) miisdes on each side of the spinous processes. 

The pectoralis major muscle arises from the sternal half of the clavicle, from 
the sternum and costal cartilages as low as the sixth or seventh rib, and from the 

\7 



178 



APPLIED ANATOMY. 



aponeurosis of the external oblique muscle and sheath of the rectus muscle. It 
inserts into the outer lip of the bicipital groove. It is to be noted in regard to this 
muscle that it is attached only to the inner half of the clavicle and that the clavicular 



Acromial branch 

Humeral branch \ 

Cephalic vein \ \ 

Coracoid process 

Deltoid 

Clavi pectoral fascia 




Costocoracold 
membrane 



Superior 
'thoracic vessels 
and nerves 



\ Thoracic branch 

Acromial thoracic artery 

Pectoralis major Pectoralis minor 

Fig. 20 1. — The clavipectoral fascia. 

and sternal parts are separated by a cleft. When removing it in excision of the 
breast for carcinoma one separates the muscle by passing through this cleft and 

detaching the part below. It forms the anterior 
/j fold of the axilla and by following this fold to the 

chest- wall it leads to the fifth rib, as it is at that 
rib that the muscle leaves the chest-wall. 

The pectoralis major is covered by the pec- 
toral fascia. When in removal of the 
female breast for nonma- 
lignant growths the breast 
is raised, the muscle be- 
neath is seen to be covered 
with a thin fascia continu- 
ous with the fascia of the 
axilla. Beneath the pec- 
toralis major is the clavi- 
pectoral fascia continuous 
with the costocoracold 
membrane above and the 
axillary fascia at the sides. 
The pectoralis 
minor passes from the 
third, fourth, and fifth ribs 
to the coracoid process. Its 
origin is well forward to- 
ward the anterior extremi- 
ties of the ribs and, as it is 
not attached so low on the 
chest as is the pectoralis 
major, it is hidden by the latter and does not aid in forming the anterior axillary fold. 
This muscle is frequently removed in operations for carcinoma of the mammary gland. 







*^, 




Fi 



202. — The serratus anterior muscle arising 
nine upper ribs. 



by ten digitations from the 



THE THORAX. 



179 



The serratus anterior (magnus) muscle (Fig. 202) passes from the side of 
the chest to the vertebral or posterior border of the scapula, arising by nine or ten 
digitations from the eight or nine upper ribs, the second having two. The slip arising 
from the sixth rib is the one most prominently seen on raising the arm away from 
the side, it passes the farthest forward. The slips into the fifth, seventh, and eighth 
ribs may also be seen. This muscle passes across the axilla from in front backward, 



Stemomastoid 

Splenius 

Levator (anguli) scapulae 

Scalenus medius 



Infraspinatii 




Latissimus dorsi 



External obliqui 



Internal oblique' 



Petit's triangl 



Fig. 203. — Muscles of the back. 



lying on the chest-wall, 
fifth, sixth, and seventh 
respiratory nerve of Bell. 



It is supplied by the posterior thoracic nerve from the 
cervicals. This nerve is also called the long external 
The interrial 'respiratory nerve is the phrenic, which comes 
from the third, fourth, and fifth cervical nerves. One of the main functions of this 
muscle is to keep the scapula applied to the chest and to aid in rotating it in elevation 



i8o APPLIED x\X ATOMY. 

of the arm. When it is paralyzed the arm cannot be raised beyond a right angle 
and the scapula projects, particularly at its lower angle and posterior edge. This 
condition is called ' ' winged scapula. ' ' 

The trapezius muscle (Fig. 203) has the shape of a triangle, its apex being out 
on the acromion process and its base in the median line. It arises posteriorly from 
the inner third of the superior curved line of the occiput, the occipital protuberance, 
ligamentum nuchse, and the spines of the se\'enth cervical and all the thoracic vertebrae. 

It inserts into the outer third of the clavicle and the acromion and spinous proc- 
esses of the scapula. It aids in rotating the scapula and elevating the shoulder; its 
paralysis is followed by marked dropping of the shoulder. It is supplied by the 
spiiial accessory nerve., which is sometimes injured in operations for tumors involving 
the posterior cerxical triangle. 

The latissimus dorsi muscle arises from the spinous processes of the lower six 
thoracic vertebrae, from the posterior layer of the lumbar fascia, the outer lip of the 
posterior third of the iliac crest and by digitations from the lower three or four ribs. 
Sometimes it is attached to the angle of the scapula. It unites with the tendon of the 
teres major muscle to be inserted into the bottom of the bicipital groove and extends 
somewhat higher than the tendon of the pectoralis major. A bursa, which may 
become inflamed, sometimes lies betw^een the muscle and the inferior angle of the 
scapula. The latissimus dorsi and teres major muscles form the posterior axillary fold. 

The erector spinae (sacrospinalis) muscle fills up the hollows on each side of 
the spinous processes. As the various muscular bundles are inserted into the vertebrae 
by innumerable small tendinous slips, in exposing the vertebrae in performing lamin- 
ectomy it is necessary to cut them w^ith a knife or scissors. One should not attempt 
to separate them by blunt dissection. These muscles become atrophied in cases in 
which the spine becomes distorted. 

SURFACE ANATOMY OF THE THORAX. 

On looking at the chest one should note whether or not it appears normal. It 
may show the rounded form of emphysema or the flat form of phthisis. One side 
may be larger than the other, suggesting pleural effusion. The intercostal spaces 
may be obliterated, indicating the same condition. This may be local instead of over 
the whole chest. Note whether Harrison's groove, funnel and pigeon breast, or 
beading of the ribs, already described, are present. Aneurism affecting the great 
vessels may cause a bulging in the upper anterior portion, and cardiac disease may 
produce marked changes in the apex beat. This may be displaced to the right side 
by pleural effusion. 

The clavicle belongs to the shoulder-girdle and hence will be described with the 
upper extremity. Both it and the sternum are subcutaneous and can readily be felt 
beneath the skin. The point of junction of the first and second pieces of the sternum 
is opposite the second costal cartilage. It forms a distinct prominence, which is 
readily felt and is a most valuable landmark. It is called the angulns sterni or angle 
of Louis. There is usually a palpable depression at the junction of the second 
piece of the sternum and xiphoid cartilage. 

The tip of the xiphoid or ensiform cartilage can be felt about 4 cm. below the 
joint between it and the second piece of the sternum. The top of the sternum is oppo- 
site the lower edge of the second thoracic vertebra. The angulus sterni is opposite 
the fifth vertebra, the lower end of the second piece of the sternum is opposite the 
tenth, and the tip of the ensiform cartilage is opposite the eleventh thoracic ver- 
tebra. There is usually comparatively little fat over the sternum, so that in fat and 
muscular people its level is below that of the chest on each side. Above its upper 
end is the suprasternal notch or depressio7i, below its lower end is the infrastertial 
depression or epigastric fossa., sometimes called the scrobicuhis cordis. 

With the upper end of the sternum articulate the clavicles. The sternoclavicular 
joint possesses an interarticular cartilage between the clavicle and the sternum. This 
separates them sufficiently to allow the formation of a distinct depression, which can 
readily be felt. From the sternum to the acromion process the clavicle is subcuta- 
neous. Below the inner end of the clavicle the first rib can be often seen and felt. At 



THE THORAX. 



i8i 



the middle of the cla\'icle it is so deep from the surface as not to be accessible and 
here the second rib is the one which shows just below the clavicle. In children the 
point of junction of the cartilages and ribs can often be distinguished; this is par- 
ticularly so in cases of rachitis. 

The line of junction between the body of the sternum and the ensiform cartilage 
can be distinguished, and to each side of it is felt the cartilage of the seventh rib, 
the last that articulates with the sternum. The tenth rib is the lowest which is 
attached anteriorly, the eleventh and twelfth being shorter and floating ribs. The 
intercostal spaces are wider anteriorly than posteriorly and the third is the widest. 

The nipple is usually in the fourth interspace or on the lower border of the fourth 
rib and on a line a little to the outer side of the middle of the clavicle. In women its 
position is variable, o .ving to the breasts being pendulous. The mammary gland 
reaches from the third to the seventh rib. As the pectoralis major muscle does not 
arise lower than the sixth rib it is seen that the mammary gland projects beyond it, an 
important fact to be remembered in operations for remox-al of the breast. 

Immediately to the outer side of the upper edge of the pectoralis major, beginning 
at the middle of the clavicle and below it, is a hollow. This is the interval between 
the pectoralis major and deltoid muscles. At its upper end it is equal in width to one- 



Suprastemal notch 
Sternal end of first 
Second rib 



Angle of sternum 
opposite second rib 



Xiphostemal 
articulation 



Serrations of serratus 
anterior muscle 

Tip of ensiform process 
Infrastemal depression 




Space between deltoid and pectoralis major 
Outer end of clavicle 
Coracoid process 

Acromioclavicular joint 
Acromion process 



Fig. 204. — Surface anatomy of the thorax. 



sixth the length of the clavicle, because the deltoid is attached only to the outer 
third of the clavicle. Immediately beneath the edge of the deltoid muscle and about 
2.5 cm. below the clavicle is the coracoid process. On abducting the arm the scapula 
is rotated and the serratus anterior muscle is put on the stretch; this makes its four 
lower serrations visible. The serration attached to the fifth rib is the highest, the 
sixth is the most prominent and extends farthest forward, while below are the last 
two attached to the seventh and eighth ribs. The operation of paracentesis, or tapping 
for pleural effusion, is most often done in the sixth interspace in the midaxillary line. 
This will be about on a level with the nipple. The apex beat of the heart is felt in 
the fifth interspace, about 2. 5 cm. ( i in. ) to the inner side of the line of the nipple. 

Running down behind the costal cartilages and crossing the intercostal spaces 
about a centimetre from the edge of the sternum is the internal mammary artery. 
When it reaches the sixth interspace it divides into the superior epigastric, which 
goes downward in the abdominal walls, and the musculophrenic, which passes to the 
attachment of the diaphragm along the edge of the chest. 

( The relations of the organs of the chest to the surface will be discussed later. 
The nervous supply to the surface of the chest is of interest mainly as indicating the 
probable location of the lesion in cases of fracture of the spine, and it will be described 
in the section devoted to the Back.) 



182 



APPLIED ANATOMY. 



THE MAMMA OR BREAST. 

The name mammary gland is often gi\'en to the breast, yet the latter is composed 
not only of glandular tissue but also of fibrous and fatty tissue, with the usual vessels, 
nerves, and lymphatics. In the male the glandular portion is undeveloped, the fat is 
relatively scanty, and the breast as a whole is insignificant and flat. In the virgin 
female adult it is more spheroidal. Above the nipple it is flattened and below it is 
rounded. Its general shape is circular and it covers the chest-wall from the upper 
border of the third rib to the sixth interspace. Laterally it reaches internally almost 
to the sternum and externally it overlaps the edge of the pectoralis major. It lies 
imbedded in the superficial fascia. In its development it is simply a modified seba- 
ceous gland. Beginning by a finger-like growth from the skin it burrows its way into 
the superficial fascia. It becomes compound and sends its branches in various direc- 
tions, especially does it extend deeper until finally it pushes away most of the fat and 




^i- 



Areola 



Areolar glands 




Nipple 



Lobule of gland-tissues 



Excretory duct 



Ampulla 
Lactiferous duct 
Fig. 205. — The secreting structure of the breast. (Piersol.) 

rests on the fascia covering the pectoralis major muscle. This is wh)- we find almost no 
adipose tissue beneath the gland but mostly between the glandular structure and the 
skin and around its edges. The shape of the virgin breast is due mainly to its adipose 
tissue and not to its glandular structure. In those who have borne children the breasts 
become enlarged, lax, and pendulous. After lactation is completed they again 
retract but rarely regain their former shape. During lactation the fatty portion of the 
breast may disappear and lea\'e it apparently in a shriveled condition, yet such a breast 
may be functionally quite active. Therefore the size of the breast is no criterion of its 
milk-producing powers. 

The secreting structure, racemose in character, is divided into ten to 
sixteen lobules each of which has its duct. These lactiferous ducts begin in the 
acini and end in the nipple. Beneath the nipple they are dilated, each forming a 
sinus or ampulla. While the shape of the breast is regular in its outline the 
glandular tissue is not so. It possesses three projections or cusps. One of these 
projects inward nearly or quite to the sternum, while the other two project toward 
the axilla and side, one being lower than the other. These are the most common 



THE MAMMA OR BREAST. 



183 



Suspensory band- 



Pectoral muscle 



directions in which the glandular tissue is prolonged, but it may extend farther 
than usual in any direction ; hence the wide incisions made in cases of carcinoma. 

According to H. J. Stiles {Ed. Med. Joicrn., 1892, p. 1099), the secreting 
structure may extend posteriorly into the retromammary tissue between the layers 
of the pectoral fascia. Anteriorly it is prolonged with the fibrous tissue (^ligaments 
of Cooper) almost to the skin. 

The nipple, located below and to the inner side of the centre of the gland, 
has connected with it some circular and longitudinal unstriped muscular fibres. 
The longitudinal ones are attached to the lactiferous ducts and serve to retract 
the nipple, the circular ones to erect it. Surrounding the nipple is the areola. 
It is pink in the virgin and about 2,5 cm. in diameter. After pregnancy its hue 
becomes brownish. The tubercles of AIontgo7nery are the numerous elevations 
found on the areola. They are more or less 
modified sebaceous glands and enlarge during 
pregnancy. As they secrete a milky fluid, they 
are often regarded as accessory milk ducts. 
There is no fat in the nipple or areola. 

The fibrous structure of the gland 
envelops the adipose and glandular tissue. 
It is simply a continuation of the fibrous septa 
of the superficial fascia. These septa are at- 
tached to the skin above, envelop and pass 
between the fatty and glandular lobules, and 
form a thin co\'ering for the under surface of 
the gland. The breast is sometimes spoken of 
as having a capsule, but that simply refers to 
the fibrous tissue just described. This fibrous 
tissue follows largely the ducts, hence when 
affected with carcinoma it contracts and draws 
the nipple in. This forms the retracted nipple 
of that disease. The fibres that go to the skin 
have been named the ligaments of Cooper. 
The fibrous tissue forms a net-work in the 
meshes of which are packed the glandular 
structure and fat-lobules. It is this which 
gives the firmness and shape to the virgin 
breast. In lactation, the fibrous tissue softens 
and stretches to accommodate the increase in 
the glandular structure and this, with the loss 
of fat, causes the breast to become lax and 
pendulous. In palpating a normal breast be- 
tween the fingers and the thumb, this firm- 
ness may feel like a foreign growth; hence 
this method of examination is not to be relied 
on. A better way is to have the patient re- 
cline, and lay the fingers flat on the breast, 
compressing it on the chest-wall beneath. 
This flattens the glandular structure and any mass can be more surely detected. 

The fibrous tissue between the glandular structure and the pectoralis beneath 
is quite thin and loose, with large spaces in it which have been called the sjtb- 
mammary bursa. Pus readily spreads in this loose submammary tissue, but in the 
gland itself only with dilticulty. 

Blood Supply. — The breast is supplied with blood from above by th& pectoral 
bra7ich of the acromial thoracic artery, which leaves the axillary artery at the inner 
border of the pectoralis minor muscle. The pectoral branch descends between the 
pectoralis major and minor and anastomoses with the intercostals and long thoracic. 
It sends branches through the pectoralis major muscle, and in carcinoma of the gland 
it may be seen much enlarged running downward on the chest-wall beneath the 
muscle. From the inner side come \\\q. perforating brayiches of the internal mammary 




Gland- 
tissue 



Fascial envelope 



Fig. 206. — Sagittal section of mamma of young 
woman who had never borne children; hardened 
in formalin. (Piersol.) 



i84 



APPLIED ANATOMY. 



artery from the second to the sixth rib; the second, third, and fourth are the largest 
and may bleed freely in detaching the pectoralis major. To the outer side and 
below is the lo7ig thoracic artery, also called the external mammary; it descends 
along the outer edge of the pectoralis minor, sending branches inward around the 
edge of the pectoralis major to the mammary gland. The intercostal arteries also 
contribute somewhat to the blood supply of the gland. 

Lrymphatics. — The breast is exceedingly well supplied with lymphatics. 
They are composed of a deep set around the lobules and ducts, and a superficial set 
which together with the deep lymphatics forms a plexus around the nipple called the 
subareolar plexus. They drain mainly toward the axilla into the lymph-nodes along 
the edge of the pectoralis major but also communicate with the nodes around the 
subclavian artery and those in the anterior mediastinum which accompany the inter- 
nal mammary artery. 

The axillary nodes are in three sets: one along the edge of the pectoralis 
major muscle {pectoral nodes), another further back along the anterior edge of the 
scapula (^scapular nodes), and a third following the course of the axillary artery 



Delto-pectoral node 



Brachial node 



Subscapular node 



Anterior pectoral node 

Vessel passing to anterior 

pectoral node 



Inferior pectoral node 




Subclavian node 



Vessel passing to 
subclavian node 



Intermediate node 



Subareolar plexus 
over mammary 
gland 



Fig. 207. — Lymphatics of the breast. (Poirier and Cun^o.) 

{humeral nodes). In addition to these there are some ififraclavicular or subclavian 
nodes between the deltoid and pectoralis major and at the inner edge of the pectoralis 
minor muscles; these are comparatively rarely involved primarily. The axillary 
nodes are continuous and communicate with the subclavian and supraclavicular nodes, 
and these latter are frequently enlarged subsequent to the axillary infection. The 
anastomosis of the lymphatics across the median line has been thought to account 
for the occurrence of the disease in the opposite breast or axilla. As shown by 
Sappey, some if not all of the lymphatics of even the sternal portion of the breast 
drain into the axilla and not into the anterior mediastinum, thus accounting for the 
axillary in\'olvement when the inner portion of the breast is affected. These five 
sets of nodes communicate with each other, and any one may be alone involved. 
The supraclavicular set do not become involved primarily because no vessels run 
directly from the breast to them; they are affected secondarily to involvement of the 
axillary or subclavian sets. 

The deep lymphatics of the breast, according to Sappey, follow the ducts to the 
areola, there anastomosing with the superficial lymphatics to form what he called the 
subareolar plexus, which drains by two trunks into the axilla. The lymphatics of the 



THE MAMMA OR BREAST 185 

breast anastomose with those of the surrounding structures; hence in certain cases the 
pectoralis muscles and even the pleura may be affected, and when the disease is widely 
disseminated by the lymph-channels on the chest-walls there is produced the thick- 
ened, brawny, infiltrated condition known as the cancer "'en cuirasse'' of Velpeau. 
Nerves. — The breast and the skin over it are supplied from the descending 
branches of the cervical plexus, by thoracic branches from the brachial plexus, and 
by the second, third, fourth, fifth, and sixth intercostals. These are not of so much 
practical importance as the lateral branches of the second and third intercostal 
nerves. That of the second is called the intercostobt'achialis (^humeral) nerve ; it 
crosses the axilla, anastomoses with the medial brachial {^lesser internal) cutaneous 
nerve, and supplies the skin of the inner and upper portion of the arm. The third 
intercostal anastomoses with the second and gives a branch to the arm and to the 
dorsum of the scapula. These nerves are certain to be seen in clearing out the axilla. 
Their division is accompanied by no paralysis, but disturbance of them accounts for 
some of the pain and discomfort following the operation. 

Abscess of the Breast. 

Suppuration in the mammary gland is usually due to infection which has 
entered the gland either through the lymphatics or the lactiferous ducts. The 
starting point of the infection is thought to be an ulcerated crack or fissure of the 
nipple. Infection travelling into the gland by way of the lymphatics would cause 
pus primarily in the pericanalicular tissue but it would soon involve the lactiferous 
ducts and then pus might exude from the nipple. Infection travelling up the ducts 
might reach the ultimate lobules and therefore give rise to widespread and multiple 
abscesses. Suppuration in this gland resembles that in the parotid gland, already 
described. When the body of the gland is involved it is apt to be so in more than 
one spot. The infection follows the branching of the ducts and usually there are 
several small abscesses instead of one large one. If there is a large collection of pus 
it is not contained in one cavity but more likely in several. This is so often the case 
that in treating these abscesses it is advised that they should not only be incised but 
the finger should then be introduced and the partitions separating the various abscess 
cavities broken through. 

In its incipiency a lymphatic infection may cause a single collection of pus, but 
this soon breaks through into the canaliculi and infects and involves the glandular 
structure. In an early stage of duct infection several inflammatory areas may start 
up about the same time. The pus soon breaks through the canaliculi and involves 
the periglandular tissue so that in each mode of infection the condition soon becomes 
the same. It is for this reason that it is difficult to say whether the infection origi- 
nated in the lymphatics or the ducts. 

When the ducts are inflamed the pus often finds a vent at the nipple. The fre- 
quency of this is the reason why direct infection of the ducts is regarded as the more 
common mode. In incising a mammary abscess the incisions should follow the course 
of the ducts, that is, they should be made in a direction radiating from the nipple towards 
the circumference and not transversely, otherwise healthy ducts will be divided. 

Submammary Abscess (for subpectoral abscess see page 264). — As has been 
pointed out some of the glandular tissue dips down to the pectoral fascia, hence 
when some of these deepest lying lobules are inflamed the pus instead of breaking 
laterally into the adjoining lobules or tissue breaks into the submammary tissue and 
bursa. Here it spreads rapidly beneath the gland and raises the gland above it. 
As the pus accumulates it sinks downward and works its way outward to the lower 
outer quadrant along the ^i}^^Q. of the anterior axillary fold. Here is where it should 
be opened. As the cavity is single one incision is sufficient to drain it. 

Tumors of the Mammary Gland. 

Benign Tumors. — There are two main kinds of benign mammary growths, 
cystic and adenomatous or fibro-adenomatous. 

Cystic growths due to retention of secretion of the ducts occur as small, rounded 
tumors, painful and tender to the touch, and are seen between the ages of 25 and 35 



1 86 APPLIED ANATOMY. 

years. They are not in any way dangerous. They are composed of a number of 
dilated acini. Another form is degenerati\'e in character, occurring in the decline of 
life, and consists of a large number of various sized, usually small, cysts located 
mostly toward the deep surface of the gland. They contain mucoid and degenerated 
material produced by the lining membrane of the acini. The whole breast is apt to 
be studded with small shot-like cysts and both breasts are visually involved. This 
affection in itself is not malignant, but it may become so by intracanalicular growths 
springing up from the walls of the cysts. 

Adenomatous growths are encapsulated, usually single, and are composed of 
three distinct elements. These are glandular tissue more or less normal in character, 
glandular tissue cystic in character, and fibrous tissue. The fibrous tissue forms the 
capsule as well as the stroma in the meshes of which latter glandular tissue, nearly 
normal, occurs. These are called fibro-adenoniata and if the glandular tissue is 
quite abundant they may be called adenomata. If the glandular acini are dilated 
so as to overshadow the fibrous portion, then it is called a cystic adenoma. These 
cystic growths may be quite large. 

Malignant Tumors. — The malignant growths of the breast are either sarco- 
mata or carcinomata. 

Sarcomata originate from the fibrous stroma of the breast surrounding the ducts 
and acini. As it increases in size it may irritate the glandular structure and obstruct 
the ducts, thus forming cysts which may be quite large. Such a growth has been 
called a cystic sarcoma. It also shows itself as a single tumor, which may be large 
but solid. The lymph- nodes are rarely affected. The disease when it wanders 
from the seat of the primary growth shows itself in some of the internal organs. It 
is disseminated by the blood and not by the lymphatics. 

Carciyiomata originate from the epithelium lining the ducts and acini. For our 
purposes we may divide them into two classes, those that grow into the ducts {intra- 
canalicular^ and those that break through the ducts and invade the surrounding 
tissues, of these scirrhus is the type. 

Intraca7ialicular growths have by many authors been considered nonmalignant on 
account of the rarity of their producing general infection. They grow at times rapidly 
and produce tumors of considerable size. On section they contain many cysts and 
into these cysts, which are derived from the dilated milk-ducts, protrude outgrowths 
from the walls. Sometimes the cavity of the cyst has its liquid contents replaced by 
the solid tumor which has grown into it. A discharge of bloody serum from the 
nipple is common in these growths. 

Scirrhus is the ordinary form of cancer of the breast. It starts in the epithelial 
structures of the gland, breaks through the basement membrane and in\olves the 
structures immediately adjacent to it, and is disseminated more widely by the lym- 
phatics. Paget s disease is a true carcinoma which begins as an eczema or ulceration 
around the nipple and later becomes disseminated. 

Carcinoma follows the gland structure, and readily involves the pectoral fascia 
covering the pectoralis major muscle. Anteriorly, the gland structure in places 
follows the ligaments of Cooper to the skin above, hence the frequency with which 
the skin is involved. 

The scirrhus variety does not involve the ducts in the same manner as does the 
intracanalicular variety, hence bloody discharges from the nipple are not so common 
as in that affection. The disease, when affecting the region of the nipple, has been 
considered more dangerous because of the greater development of the lymphatics, 
particularly the subareolar plexus of Sappey, at that point. 

Carcinomatous disease extends especially by way of the lymphatics. These 
follow the fibrous and canalicular structure, therefore on section the cancerous tissue 
can be seen extending like roots into the surrounding gland. This tissue shrinks, 
contracts, and becomes harder as the disease progresses, that is why retraction of the 
nipple and dimpling of the skin occurs. The most free lymphatic drainage occurs 
toward the axilla, not toward the mediastinal nodes. The first nodes to show infec- 
tion are those lying along the edge of the pectoralis major muscle about the level of 
the third rib. Later, the nodes at the anterior edge of the scapula accompanying the 
subscapular artery become involved, or those along the axillary vessels. Still later 



THE MEDIASTINUM. 187 

those along the subcla\'ian vessels may be enlarged and may be felt abo\e the clavicle 
and farther inward behind the sternomastoid muscle low down. 

In rare instances the disease may be carried superficially to the subclavian nodes 
in the infraclavicular triangle between the deltoid and pectoralis major muscles. 
Should the disease spread, it may be carried by the lymphatics to the opposite breast 
directly across the median line. If it involves the lymphatics of the chest-wall gen- 
erally there is produced the brawny condition of the skin called cancer ' V« C7d?-asse'' 
of Velpeau already alluded to. A cancerous nodule beyond the edge of the pectoralis 
major muscle is not necessarily an enlarged node, but may be due to the involvement 
of one of the cusps of the gland, which sometimes extend even into the axilla. 

Removal of the Cancerous Breast. — The origin of cancer is now believed 
to be local and not general and the more complete its removal the greater is the 
likelihood of cure. Therefore every effort is made to excise every possible infected 
tissue. This has led to the performance of very extensive operations. 

The incision is made so large as to include nearly or quite all of the skin 
covering the glandular tissue; this is because of the intimate connection of the 
two, as already pointed out. It is carried out to the arm; this is to facilitate 
clearing out the axilla and all its contents. The incision is kept close to the skin; 
this is to avoid any glandular structure which may possibly be beneath. The 
pectoral fascia covering the pectoral muscle is always removed. 

Often both the pectoralis major and minor muscles are removed. In excising 
them the slight interspace between the clavicular and sternal fibres of the pectoralis 
major muscle is entered and the muscle detached from the anterior extremities 
of the ribs and sternum. In so doing the anterior intercostal arteries, particularly 
those of the second, third, and fourth spaces, are liable to bleed freely. As the 
pectoralis major is detached and turned outward, the acromial thoracic artery is 
seen at the inner edge of the pectoralis minor muscle with its pectoral branch 
running down the surface of the chest. This may be ligated, the finger slipped 
beneath the pectoralis minor, and this muscle cut loose from the coracoid process 
above and the third, fourth, and fifth ribs below. At this stage some operators 
clear the subclavian and axillary vessels of all loose tissues and lymph-nodes. 

The vessels are followed out on the arm. When the insertion of the pecto- 
ralis major is reached it is detached and the whole mass turned outward and pared 
loose along the anterior edge of the scapula. Thus it is removed in one piece. 
The part of the chest-wall which has been cleared off embraces from the middle 
or edge of the sternum to the anterior edge of the scapula and from near the 
lower edge of the chest below to the clavicle above. The vessels ha\'e been 
cleared off from the insertion of the axillary folds on the arm to underneath the 
clavicle. Many operators make an additional incision above the clavicle and clear 
out the supraclavicular fossa even if no enlarged glands can there be detected. 
Sometimes the long thoracic artery and thoracicalis longus (long external thoracic) 
nerve may be wounded, but they need not be. (See note, page 191.) 

Two nerves will be seen crossing the axilla from the chest to the arm. They 
are the lateral branches of the second and third intercostal nerves. The second is 
called the intercostobrachialis (humeral) nerve. If they can conveniently be spared 
it is to be done, otherwise they are divided. In clearing the axillary vessels, small 
veins and even arteries may be divided close to the main trunks. These may 
be expected to bleed freely but are usually readily secured. Care should be taken 
not to wound unnecessarily the subscapular artery and particularly the vein as they 
wind around the anterior edge of the scapula 2 to 3 cm. below its neck. Some operators 
prefer to detach the breast from without in instead of from within out as described. 

THE MEDIASTINUM. 

The mediastinum is the middle space of the chest between the spine behind, the 
sternum in front, and the pleurae to each side. It is subdivided into a superior 
inediastin?i))i, which is the part above Ludwig's angle, between the first piece of the 
sternum in front and the vertebrcE from the first thoracic to the upper portion of the 
fifth behind. The part below is divided into the anterior mediastinum, the middle 
-mediastinutn, and ihe. posterior mediastinum. 



i88 



APPLIED ANATOMY. 



Superior Mediastinum. — The upper level of the superior mediastinum is 
oblique, as it runs from the upper edge of the sternum to the first thoracic vertebra. 
The lower level of the superior mediastinum runs from the junction of the first and 
second pieces of the sternum to the upper border of the fifth (or lower border of the 
fourth ) thoracic vertebra. Laterally it is bounded by the pleurae and apices of the lungs. 

The distance from the anterior surface of the spine to the posterior surface of the 
sternum is quite small, being only 5 to 6 cm. (2 to 2^ in.). Through this pass 
most important structures. The trachea and oesophagiis are in the median line as well as 
the remains of the thymus gland. To each side are the great vessels, the innomi7iate 
artery being on the right and the subclavian and carotid on the left. The left innomi- 
nate vein crosses transversely just below the top of the sternum to meet the innomiyiate 
vein of the right side and form the siiperior vena cava. Into the innominate veins 
empty the irferior thyroid^ vertebral, superior intercostal, iiiternal mammary, and 



CEsophagus — } 

Innominate arten,' 
Left innominate vein — /- -4' 
Arch of aorta 



Sternum 
Ascending aorta 

Right ventricle 
Right auricle. 

Diaphragm 




— Trachea 



'IV thoracic vertebra 



Right pulmonary 
artery 



.Left auricle 



—CEsophagus 



Inferior vena cava 



Liver 



Spigelian lobe 



Fig. 208. — The superior (red), anterior (blue), middle (yellow), and posterior (green), mediastina. 

(Modified from Piersol.) 

pericardial veins ; and into the descending vena cava empties the vejia azygos major. 
On the posterior surface of the oesophagus and afterwards to its left side passes the 
thoracic duct. The trachea bifurcates opposite the junction of the first and second 
pieces of the sternum, and the transverse portion of the arch of the aorta rises as high 
as the middle of the manubrium. The phrenic nerves lie against the pleura, the 
right having the vena cava to its inner side. 

The right vagus {p7ie7imogastric^ 7ierve comes down between the innominate 
artery and vein and passes downward on the posterior surface of the oesophagus. It 
gives its recurrent laryngeal branch off at about the right sternoclavicular joint. 
The left vagus nerve comes down to the outer side of the left carotid artery and 
goes over the arch of the aorta, giving ofT its recurrent laryngeal branch, and thence 
proceeds to the anterior surface of the oesophagus. The presence of the trachea in 



THE MEDIASTINUM. 



189 



the median line and the edges of the lungs which meet opposite the second rib give 
a resonant percussion note to the first piece of the sternum. With all these 
important structures crowded in the small space between the vertebrae and sternum 
it is easy to see why tumors in this region should cause serious symptoms. 

Aneurism involving the arch of the aorta and the great vessels is common. 
Tumors, such as sarcoma, carcinoma, and glandular, though rare, do occur. 
Abscess from high dorsal Pott' s disease has been known to cause serious effects. 

The symptoms of all these affections resemble one another to a considerable 
extent. Interference with the blood-current, usually in the veins, almost never in 
the arteries, is marked. Alteration in the voice is produced by pressure on the 
recurrent laryngeal nerves. Dyspnoea from the pressure on the trachea and diffi- 
culty in swallowing also occur, as well as interference with the circulation and the 



Descending 

vena cava 
Left pulmonary 

artery 

Left bronchus 

Left pulmonary 
veins 



Right atrium 
(auricle) 




Vagus nerve 

Internal jugular vein 

Common carotid artery 

Subclavian vein 

Left innominate 
vein 

Phrenic nerve 

Subclavian artery 

Vagus nerve 

Aorta 



Trachea 

Bronchial 

lymph-node 

Pulmonary 

artery 

Pulmonary 

veins 



Right ventricle 



Fig. 209. — Contents of the mediastina viewed from the front. 

action of the heart. The presence of growths in this region is indicated also by the 
presence of dulness o\'er the region of the manubrium. 

Anterior Mediastinum. — This is the space below the second costal cartilages, 
between the sternum in front, the pericardium behind, and the two pleurae on the 
sides. It is only a narrow slit in the median line above from the second to the 
fourth costal cartilage; from here the right pleura is prolonged obliquely down and 
outward to the seventh costal cartilage, which it follows. On the left side the pleura 
leaves the median line about the fourth cartilage and passes out about 2 cm. to the 
left of the sternum and then down to the seventh costal cartilage, which it follows. 
The triangularis sterni muscle arises from the under surface of the lower third of the 
sternum and from the xiphoid cartilage and passes upward and outward to insert 
into the costal cartilages of the second to the sixth ribs inclusive. The muscle lies 
in front of the anterior mediastinum and the internal mammary artery runs down 
between it and the bone about i cm. distant from the edge of the sternum. There 
are a few lymphatic nodes in the anterior mediastinum on the diaphragm below and 



I go 



APPLIED ANATOMY. 



in the superior mediastinum on the arch of the aorta and left innominate vein above. 
A chain of nodes also accompanies the internal mammary artery along the edge of 
the sternum between the pleura and chest wall. 

Abscess of the anterior inediastiriiim may result from infection due to injury or 
punctured wounds. It may break into the pleurae on the sides, into the pericar- 
dium posteriorly, work its way down toward the abdomen, or point in the intercostal 
spaces at the edge of the sternum. 

Paracentesis pericardii is performed in the sixth interspace close to the sternum; 
also, the fifth and sixth cartilages may be resected, the internal mammary artery 
ligated, and the pericardium opened and even drained. 

If one attempts to pass a trochar into the pericardium by a puncture through 
the fifth or sixth interspace sufficiently far out to avoid wounding the internal 
mammary artery the pleura is apt to be wounded, as it passes farther toward the 
median line than does the lung. 

The Middle Mediastinum. — The middle mediastinum is limited in front by 
the anterior wall of the pericardium and behind by the posterior wall of the pericar- 
dium and roots of the lungs. It contains the heart with the lower half of the desce?id- 
ing vena cava and the vena azygos major emptying into it, and the asce?iding aorta; 



Thoracic duct- 
Phrenic nerve 
Recurrent laryngeal nerve 
Common carotid artery. 

Bronchial artery. 
Pulmonary artery- 




""CEsophagus 
Vagus nerve 
Phrenic nerve 

Vena azygos major 
■Right bronchus 

•Right pulmonary artery 
Pulmonary vein 



Left vagus nervi 
Left bronchu: 

Pulmonary vein 
Aorta- 
Thoracic duct- 
Vena azygos major- 

FiG. 2IO. — Contents of the mediastina viewed from the rear. 

also the structures forming the roots of the lungs, viz., the right and left bronchi, 
and \.\\e pnhnonary arteries and veins."^ T\\g phrejiic nerves lie between the pericar- 
dium and pleurae anteriorly. 

The bronchial lymphatic nodes are numerous between the structures forming the 
roots of the lungs. It is these nodes that are so often enlarged in diseases of the 
lungs. They are affected in malignant disease as well as in tuberculosis, etc. Enlarge- 
ments of the heart pressing on the vessels, particularly the vena azygos major, are 
sometimes thought to cause pleural effusions, especially if one-sided. 

When the pericardium is distended with fluid it enlarges more in an up and down 
direction, but when the heart is enlarged its size increases mainly laterally — from side 
to side. 

Posterior Mediastinum. — The posterior mediastinum extends from the peri- 
cardium and roots of the lungs anteriorly to the vertebrae posteriorly. The pleurae 
are on each side. Behind the pericardium runs the oesophagjcs, lying in front of the 
aorta, which rests on the vertebrae. In the chink between the aorta and bodies of 
the vertebrae lies the thoracic duct and immediately to its right side is the vena azygos 

* The mediastina are arbitrary divisions, and it is a question as to whether the roots of the 
kings should not be included in the posterior instead of the middle mediastinum. 



THE MEDIASTINUM. 191 

major. The vena azygos minor is on the left side of the vertebrae and crosses the 
sixth to join the vena azygos major. The descending thoracic aorta is not infrequently 
the seat of aneurism. 

Mediastinal Tumors. — Cancer is the most frequent malignant new growth, then 
sarcoma and lymphoma. Great enlargement of the lymph-nodes occurs in Hodgkiii'' s 
disease and is probably a factor in causing a fatal issue. Enlargements also result 
from tuberculosis and other diseases. They give rise to pressure symptoms. Dyspnoea 
may be due to pressure on the trachea or heart and great vessels. The circulation 
may be so much impeded that the enlargement of the collateral veins, especially those 
of the surface, may be \ery marked. There may also be difficulty of swallowing due 
to pressure on the oesophagus. 

Pleural Effusions. — Serous effusions into the pleurae are also known to accom- 
pany heart disease and have been attributed in some instances to obstruction of the 
circulation. They are apt to be unilateral and are most often found affecting the 
right pleural cavity. Baccelli attributed the effusion to obstruction of the blood 
current through the vena azygos major ; the enlarged heart pulling the superior vena 
cava down drew the vena azygos major tightly over the right bronchus, as is well 
shown in Fig. 210. Steele ( Univ. Med. Mag., 1897 ; Jonrn. Am. Med. Asso.^ 1904) 
and Stengel ( Univ. Penna. Med. Bulletin, 1901 ) held that the dilated right heart by 
extension upward exerts pressure on the root of the right lung and indirectly pinches 
the azygos major vein as it curves over the right bronchus to enter the superior 
vena cava. Fetterolf and Landis (^Am. Journ. Med. Sciences, 1909) believe that 
the fluid comes from the visceral pleura and not from the parietal pleura, and that the 
outpouring, so far as the pressure factor is concerned, is caused by dilated portions 
of the heart pressing on and partly occluding the pulmonary veins. They point out 
that Miller {Am. Journ. of Anat., vii) has shown that the veins draining the visceral 
pleura empty into the pulmonary veins ; therefore, if these latter are obstructed, 
transudation may ensue ; this may occur on either side. They point out that if the 
right atrium (auricle) dilates, it expands upward and backward and compresses the 
left auricle and root of the right lung; and of the parts composing the root the 
pulmonary veins are the most anterior, and, therefore, the ones most liable to be 
compressed. Left-sided effusions are accounted for by compression of the left 
pulmonary vein by the dilated left atrium (which is the most posterior of the four 
chambers) and its appendix. The greater frequency of right-sided effusions is due 
to the more common occurrence of dilatation of the right side of the heart. 

[VV. S. Handley {Brit. Med. Jonrn., Oct. i, 1904) claims that the principal 
method of dissemination of carcinoma of the breast is not by the lymph stream or 
blood current but by spreading peripherally along the coarser meshes of the lym- 
phatic channels which exist in the deep pectoral fascia. These are continuous down- 
ward with the surface of the recti muscles. 

He therefore advises that the lower end of the usual skin incision be prolonged 
downward and inward so " that every particle of the origin of the great pectoral from 
the rectus sheath, and the surface of the latter, on both sides of the middle line, 
should be most carefully cleared" as far as two to three inches below the tip of the 
ensiform cartilage.] 



192 



APPLIED ANATOMY. 



THE CHEST CONTENTS. 

For the sakt of convenience in description and record, the chest has been 
divided into various regions and marked by certain longitudinal lines. 

The Longitudinal Lines. 

Seven longitudinal lines are used. They run parallel with the long axis of the body. 

1. The median line means the midline of the body. This runs down trie 
middle of the sternum anteriorly and the middle of the back posteriorly. 

2. The parasternal line runs parallel to the edge of the sternum and midway 
between it and the midclavicular line. 

3. The midclavicular line, also called the mammary line, is a longitudinal 




Fig. 211, — The longitudinal lines of the chest used in physical diagnosis. 

line passing through the middle of the clavicle. This usually passes i to 2 cm. 
internal to the nipple. 

4. The anterior axillary line passes through the anterior fold of the axilla. 

5. The midaxillary line passes through the middle of the axilla. 

6. The posterior axillary line passes through the posterior fold of the axilla. 

7. The scapular line passes longitudinally through the lower angle of the scapula. 

The Regions of the Chest. 

In the middle of the surface of the chest anteriorly there are three regions: 
I. The suprasternal region is the part above the sternum between the sterno- 
mastoid muscles. It is the suprasternal notch. 



THE CHEST CONTENTS. 



193 



2. The upper sternal region extends from the suprasternal notch to a line 
drawn opposite the third costal cartilages. 

3. The lower sternal region is behind the second piece of the sternum from 
the third costal cartilages down. 

Anteriorly on the chest there are four regions (Fig. 212) : 

1. The supraclavicular region, above the clavicle. This includes the supra- 
clavicular fossa. 

2. The infraclavicular region, below the clavicle down to the upper edge of 
the third rib. 

3. The mammary region, from the upper edge of the third to the upper 
margin of the sixth rib. This extends from the edge of the sternum to the anterior 
axillary fold and has the nipple nearly in its centre. 




-The 



4. The inframammary region extends from the upper margin of the sixth 
rib to the lower margin of the thorax. 

Laterally on the chest between the folds of the axilla there are two regions: 

1. The upper axillary region extends down to the upper border of the sixth rib. 

2. The lower axillary region extends from the upper border of the sixth rib 
to the lower edge of the thorax. 

Posteriorly there are four scapular regions (Fig. 213) : 

1. The suprascapular region is above the spine of the scapula. 

2. The scapular region is the part covered by the body of the scapula below 
its spine. 

3. The infrascapular region is the part of the chest below the scapula between 
its angle and the lower edge of the chest. 

4. The interscapular region is the part between the posterior edge of the 
scapula and the median line. 

13 



194 



APPLIED ANATOMY. 



THE PLEUR/E. 

The pleurae form closed sacs which line the thorax (parietal pleura) and cover 
the surface of the lungs (visceral pleura). As the lungs expand and contract, the 
pleurae are only completely in contact with the lungs when the latter are fully dis- 
tended. In ordinary breathing the lungs are not completely expanded, hence the 
edges of the pleurae fall together and so prevent the formation of a cavity. This 
collapsing of the pleurae takes place mainly along its anterior and lower edges. The 
apex of the pleura is prevented from collapsing by its attachment to the first rib, and 
also, as pointed out by Sibson, by the attachment to it of an expansion of the deep 
cervical fascia and some fibres of the scalenus anticus muscle. Posteriorly the chest 
wall is unyielding. Anteriorly when the lungs are collapsed they fill out the pleurae 
as low down as the fourth costal cartilage ; below that, in front of the heart. 








'SUP^^/.^ 




" /NFRA 
■^ SCAPULAR 
REGION 




a space or sinus is left unoccupied by lung. It is called the costomediastinal sinus. 
Likewise between the diaphragm and chest-walls is another space, in which the 
parietal or costal and visceral layers of the pleura are in contact,^ called the costo- 
phrenic simis or complemental space of Gerhardt. From these facts it follows that the 
outlines of the pleurae and lungs are identical posteriorly, superiorly, and anteriorly, 
as low as the fourth costal cartilage. Here they diverge, the pleurae descending 
lower than the lungs. 

The top of the pleura is about on a plane with the upper surface of the first 
rib. This makes its posterior portion at the head of the first rib 5 cm. higher 
than its anterior portion at the anterior end of the first rib. The upper border 
of the clavicle is level with a point midway between the anterior and posterior 
ends of the first rib. This, therefore, shows the pleura to extend 2.5 cm. (i in.) 
above the level of the upper surface of the clavicle. 



THE PLEURA. 



195 



The top of the pleura does not project into the neck in the form of a cone, but 
resembles a drum-head, being stretched in the form of a plane almost or quite 
level with the top of the first rib. Its upper surface is strengthened by fibres from 
the deep fascias of the neck and, according to Sibson, by some fibres from the 
scalene muscle. 

The pleura then slopes forward behind the sternoclavicular joint to meet the 
pleura of the opposite side at the level of the second costal cartilage, a little to the left 
of the median line. They then descend until opposite or a little below the fourth 
costal cartilage, when they each diverge toward the side, reaching the upper border 
of the seventh costal cartilage near its sternal junction. They then slope down and 
Out, reaching the lower border of the seventh rib in the mammary line, the ninth rib 




Fig. 214. — .interior surface relations of the lungs and pleurse. 



in the a.xillary line, and the twelfth rib posteriorly (Joessel and Waldeyer, page 51). 
The scajDular line intersects the lower edge of the pleura at about the eleventh rib. 

In operations involving the lumbar region, if the incision is carried high up 
posteriorly the pleura may be opened along the lower border of the posterior 
portion of the twelfth rib. It soon recedes from the costal margin and in the 
axillary line is about 6 cm. (2f in.) above it. 

A heavy body, as a bullet, gravitates to the lowest portion of the pleural cavity, 
hence it can be removed through an incision in the eleventh interspace posteriorly. 

(Paracentesis and empyema will be alluded to after the lungs have been 
described, see p. 200). 



196 



APPLIED ANATOMY. 



THE LUNGS 

The lungs entirely fill the pleural sacs when completely distended, but only 
partly so in quiet, ordinary respiration. They are encased in a bony cage that is 
open below, on account of which, when the lungs distend, they expand mostly 
downward. To a less extent they expand, in forced respiration, both laterally 
and anteroposteriorly, due to the elevation of the ribs owing to the traction of the 
muscles upon them. Ordinary breathing is performed mainly by the diaphragm. 
It acts like the piston of a cylinder and as it descends the air is drawn into the 
trachea and lungs. As the diaphragm falls a negative pressure is produced within 
the chest and were it not for its bony framework, it would collapse. The framework 
is sufficiently strong to retain its shape in spite of this pressure if the breathing is 




Fig. 215. — Posterior surface relations of the lungs and pleurae. 

normal and the chest-walls are healthy. When, however, obstruction of the air- 
passages is present, perhaps from enlarged pharyngeal or faucial tonsils or nasal 
hypertrophies, then the deformities known as funnel-breast, pigeon-breast, etc., 
already described, arise. They are also produced if there is no obstruction to the 
breathing but only a weakness in the bony thorax, as occurs in rickets. 

Two of the most common of the diseases of the lungs produce changes in the 
shape of the thorax ; they are emphysema and phthisis. Pneumonia, though a frequent 
enough disease, does not produce any changes, as it is too short in its duration. 

In emphysema the lungs are in a state of hyperdistention, hence they fill the 
chest to its greatest capacity and tend to make the soft parts bulge between the ribs. 
In phthisis the lungs are contracted, hence the intrathoracic pressure becomes a 
negative one and the soft parts sink in between their bony support. In emphysema 
the anteroposterior diameter increases and the chest assumes the barrel-form already 
described. In phthisis it becomes lessened in its anteroposterior diameter and we 



THE LUNGS. 



197 



have the flat chest. Enlargement of the chest posteriorly is impossible on account of 
the support of the ribs, vertebrae, and strong back muscles. Enlargement downward 
is allowed by a descent of the diaphragm ; hence the fulness of the abdomen in those 
affected with emphysema and conversely the flatness of the abdomen in those having 
phthisis. In the region of the apices the thorax is closed by the deep fascia, which 
spreads from the trachea, oesophagus, muscles, and great vessels and blends with the 
pleura to be attached to the first rib. In the normal condition this is level with the 
plane of the first rib and rises little if at all above it. Even in disease it is not 
materially altered. This is certainly so in phthisis and probably so in emphysema. 
The apparent fulness of the supraclavicular fossae and intercostal spaces in emphysema 
and the increased depth of these hollows in phthisis are not due so much to a bulging 
or to a retraction of the lungs at these points as to the atrophy of the fatty and 
muscular tissue in phthisis and to the muscular tension in emphysema. 

In coughing, the apex of the lung does not jump up into the neck above the 
clavicle as it appears to do, but remains nearly or quite below the plane of the top of 
the first rib. The appearance of bulging is caused by the movements of the trachea 
in the median line and the muscles laterally. This is noticeable particularly in the 

Sternothyroid muscle 

Carotid artery 

Sternohyoid muscle 

Subclavian artery 
Vagus nerve 



Carotid artery 



Vagus nerve 



avian vein 



First rib 

Scalenus anticus 

muscle 

Subclavian vein 

Subclavian artery 



Pleura 



First rib 



Pleura 




Fig. 216. — Upper end of the thorax, at the level of the first rib. 

case of the platysma and omohyoid muscles. In quiet breathing the posterior belly 
of the omohyoid lies about level with the clavicle, but in coughing it rises i or 2 cm. 
above it. The intercostal membranes and muscles are kept tense by the constant 
elevation of the ribs due to the muscular tension. 



OUTLINE OF THE LUNGS. 

Apex. — The apex of the lung has its highest point opposite the posterior 
extremity of the first rib. It then follows the plane of the top of the first rib down 
to the sternoclavicular joint, immediately above the junction of the cartilage of the 
first rib with the sternum. The anterior end of the first rib is 5 cm. lower than the 
posterior. The upper edge of the clavicle is 2. 5 cm. or one inch, above the anterior 
end of the first rib and 2.5 cm. below the head of the first rib, hence the apex of the 
lung rises 2.5 cm. (i in.) above the clavicle, and it lies behind its inner fourth. 
This distance will vary in different individuals with the obliquity of the ribs. The 
more oblique the ribs the greater will be the distance between the level of the top of 
the clavicle and that of the neck of the first rib. 

Anterior Border. — From the sternoclavicular joint the borders of the lungs 
pass downward and inward until they almost or quite touch in the median line at the 
angle of Ludwig opposite the second costal cartilage. They continue downward 



198 APPLIED ANATOMY. 

almost in a straight line until opposite the fourth costal cartilage, where they begin to 
diverge. The border of the right lung proceeds downward and begins to turn out- 
ward opposite the sixth cartilage. 

The left lung on reaching the level of the fourth costal cartilage curves outward 
and downward across the fourth interspace to a point about 2.5 cm. to the inner 
side of the nipple in the fourth interspace. From this point it goes downward and 
inward across the fifth rib and interspace to the top of the sixth rib about 3 cm. to 
the inner side of the nipple line. This isolated tip of lung just above the sixth rib 
over the apex beat of the heart is called the lingula. 

Lower Border. — The lower edge of the lung varies in different individuals 
and in the same individual according to the amount of inflation. In quiet respi- 
ration it is about opposite the sixth cartilage and rib from the sternum to the mam- 
mary line, opposite the eighth in the midaxillary line, the tenth in the scapular line, 
and the eleventh near the vertebrae. 

The Fissures and Lobes of the Lungs. — The left lung has one fissure and 
two lobes, an upper and a lower. 

The right lung has two fissures and three lobes, an upper, a middle, and a lower. 

The fissure of the left lung begins above and posteriorly opposite the root of the 
spine of the scapula; this is level with the fourth rib and third dorsal spine. It passes 
downward and forward, ending at the sixth rib in the parasternal line. It crosses the 
fourth in the midaxillary line. The lower lobe of the right lung is of the same size 
as that of the left side. The lung above it is divided into a middle and upper lobe. 
The main fissure of the right lung corresponds in its course almost'exactly with that 
of the left lung. It begins above and posteriorly at the root of the spine of the 
scapula and passing downward crosses the fourth rib in the midaxillary line and ends at 
the sixth rib in the mammary line (instead of the parasternal line as in the left). 

The subsidiary fissure of the right lung leaves the main fissure at the posterior 
axillary line opposite the fourth rib arid follows this rib in an almost horizontal direc- 
tion to its junction with the sternum. 

In order to recognize and appreciate the changes which occur in the lungs in 
lobar pyieimionia it is necessary to know the outlines and limits of the various lobes of 
the lungs. A knowledge of the exact course of the fissures of the lungs is not only 
necessary to outline the lobes, but it is of service in the diagnosis of pleural effusions. 
These effusions often are limited to certain localized areas instead of being general. 

Pleurisy may affect the lung bordering the fissures. When such is the case, the 
effusion, serous or purulent, may be in the fissure itself and embrace but little of the gen- 
eral pleural cavity. Dry taps from failure to hit the purulent or serous collection are 
not infrequent, and the possibility of its being interlobar should be borne in mind. 

GENERAL CONSIDERATIONS. 

From what has been said it follows that a knowledge of the extent and outlines 
of the lungs and of the location and course of the fissures is essential to the proper 
diagnosis and treatment of affections of both the lungs and pleurae. 

The extent of the lungs is determined in the living by percussion. The apex of 
the lungs forms an oblique plane running upward and backward from just below the 
lower edge of the inner extremity of the clavicle to the neck of the first rib above 
and posteriorly. The level of these two points will vary according to the inclination 
of the ribs, which in turn is influenced by the direction (vertical) of the spine. Ordi- 
narily the distance is 5 cm. (2 in.). It may be even as much as 7 or 8 cm. The 
top edge of the clavicle passes across the middle of this distance so that the top of 
the lung is about 2.5 cm. (i in.) above the clavicle. The highest point of the lung 
is not in the middle of the space enclosed by the first rib, but is at its posterior 
border, at the neck of the first rib. 

In percussing, one should not strike directly backward but both downward and 
backward. 

If the patient is standing erect the first rib will slope downward and forward at an 
angle of 65 degrees, or more, with a vertical line. The spine will slope downward and 
backward from the same vertical line in a normally straight back about 20 degrees. 



THE LUNGS. 



199 



In people with straight backs and flat chests (often seen in phthisis), the sloping 
downward of the ribs is marked; in those with rounded backs the chest is apt to be 
round, as in emphysema, and then the ribs are more horizontal. 

Another point to be noticed is the lateral extent of the apex of the lung in 
relation to the length of the clavicle. The lung does not extend farther out on the 
clavicle than one-fourth its length. The clavicular origin of the sternomastoid 
muscle extends out one-third of the length of the clavicle, so that the lung is behind 
the clavicular origin of the sternomastoid and care should be taken not to percuss 
too far out. If the finger is laid in the supraclavicular fossa in percussion it should 
be pressed downward and inward, not backward. 

Posteriorly the scapula rises to the second rib and its spine has its root opposite 
the fourth rib or spinous process of the third thoracic vertebra. Therefore a small 
portion of the lung is above the upper edge of the scapula and percussion in the 
supraspinous fossa gives a clear resonant note. 

Behind the middle of the first piece of the sternum passes the trachea, crossed 
by the left innominate vein. The trachea of course contains air; the lungs slope 




JJ. Normal lung 



Heart 



Fig. 217. — Formalin-hardened body, showing the right lung collapsed and compressed by a large 

pleural effusion. 

inward from the sternoclavicular joints to meet nearly or quite in the median line 
and so continue to the level of the fourth rib; hence it follows that the percussion 
note on the sternum nearly down to this point is resonant and if it be found to be 
dull one should look for an aneurismal or other tumor which is displacing or 
covering the lungs and trachea at this point and thereby subduing their resonance. 

Below the fourth rib the area of the absolute heart dulness becomes evident. 
(This will be alluded to in describing that organ later on. ) 

In performing abdominal operations, as those involving the gall-bladder and 
kidney, the surgeon may be tempted to prolong his incision upward into the lower 
edge of the chest-walls, and it is necessary to know how far he can proceed without 
opening the pleural cavity. This necessitates his knowing how far from the lower 
edge of the chest the pleura lies. It reaches to the seventh rib in the mammary line, 
the ninth in the axillary line, and the twelfth posteriorly, extending to its extreme 
lower edge. 

In the axillary line the pleura is about 6 cm. (2| in.) away from the edge of 
the thorax. This distance gets less as one proceeds forward to the sternum and 
backward toward the spine. 



200 APPLIED ANATOMY. 

In emphysema the lung, being distended, occupies more nearly the outlines of the 
pleura and its area of resonance is increased. In pleural effusion it is compressed and even 
sometimes collapsed. As it shrinks it recedes inward and backward and is pushed 
from the chest-wall by the layer of fluid (Fig. 217). The pressure of the fluid within 
causes the intercostal spaces to be obliterated and sometimes even to bulge instead of 
being depressed. As the expansion of the lung is prevented, the chest does not move 
on the affected side, or expand with the respiration, as it does on the healthy side. 
This can be demonstrated by measuring the two sides of the chest. At the end 
of expiration the affected side will be from i to 3 cm. greater in circumference than the 
healthy one. If the pleural effusion is on the right side it may push the heart to the 
left and raise its apex beat and cause it to pulsate beyond the nipple line and even in 
the axilla. If it is on the left side the costomediastinal sinus (page 196) becomes 
distended with fluid or plastic lymph and this obscures or conceals the heart's impulse. 
If the effusion is very large the heart is pushed over toward the right and its apex 
beat is seen in the third or fourth interspace on the right side even so far over as 
the mammary line. 

Should the effusion be purulent it may perforate the chest- wall, or open into the 
pericardium anteriorly, the oesophagus posteriorly, and into the stomach or peritoneal 
cavity below. If it perforates the chest-wall it usually does so anteriorly between the 
third and sixth interspaces, most often in the fifth. 

Paracentesis. — Where the pleural effusion is serous it is usually drawn off by 
an aspirating needle or trocar. 

For diagnostic purposes a hypodermic syringe needle is often used, as the chest- 
walls are usually thin enough to allow this to be done, particularly if a suitable spot 
is chosen and the patient is a cnild. Care should be exercised not to strike a rib. 
The spot chosen for puncture may be indicated by dulness on percussion. It may 
be anywhere, but when a choice is permissible the puncture should be made in the 
sixth interspace about in the middle or postaxillary line. Another preferred spot is 
in the eighth interspace, below the angle of the scapula. The sixth interspace may be 
determined in several ways, viz. : 

1. Begin at the angulus sterni (angle of Ludwig) and follow out the second rib 
to the parasternal or midclavicular line, thence count down to the sixth rib and 
follow it to the midaxillary line. 

2. The nipple is in the fourth interspace, follow it to the axillary line and count 
two spaces down. 

3. The apex beat of the heart is in the fifth interspace, follow it around to the 
axillary line and take the next space below. 

4. Find the last rib that articulates with the sternum — it is the seventh ; follow it 
around and take the space above. 

5. With the arm to the side the inferior angle of the scapula marks the seventh 
interspace; take the interspace next above. 

6. A horizontal line at the level of the nipple cuts the midaxillary line in about 
the sixth interspace. 

7. The lower edge of the pectoralis major touches the side of the chest at the 
fifth rib. Follow it to the axillary line and go two spaces lower. 

8. By raising the arm the serrations of the serratus anterior muscle attached to 
the fifth, sixth, seventh, and eighth ribs become visible; that attached to the sixth rib 
is the most prominent and is attached farthest forward. 

Empyema. — When the pleural effusion is purulent, tapping is not sufficient, 
and drainage is resorted to. It is not considered necessary to open the pleural 
cavity at its lowest part but the sites chosen are usually the sixth or seventh inter- 
space in the mid- or postaxillary line. The movements of the scapula are apt to 
interfere with drainage immediately below its angle, hence the opening is usually 
made farther forward. The surgeon may or may not resect a rib. 

The ribs may lie so close together as to compress the drainage-tube; in such 
case a resection is done if the patient's condition permits. 

hicision for Empye^na. — In certain cases the condition of the patient may 
demand that as little as possible be done, and that quickly. The point of operation 
is selected by one of the guides already given, perhaps the level of the nipple. 



THE PERICARDIUM. 201 

While the finger of one hand marks the interspace, an incision 4 cm. {i}^ in.) 
long is made along the upper edge of the rib, this is deepened by a couple of 
strokes which detach the intercostal muscles and carefully penetrate the pleura. 
As the pus makes its appearance the knife is withdrawn and the finger is laid on 
the opening. A drainage-tube held in a curved forceps is then slid along the finger 
into the chest. Sometimes a rubber tracheotomy tube is used for drainage purposes. 
Any bleeding will be from the small intercostal branches and can readily be stopped 
by gauze packing. 

The incision is made along the upper edge of the rib because the intercostal 
artery running along the lower edge of the rib is the larger. 

Resection of a Rib for Empyema. — For the removal of a part of a rib a more 
formal operation is necessary. The incision is made directly on the rib down to 
the bone and five or more centimetres in length. The skin being retracted, the 
periosteum is incised and detached from the rib with a periosteal elevator which is 
passed down its posterior surface, pushing the pleura away from the rib. When 
the elevator reaches the lower border of the rib an incision is made down on it 
through the intercostal muscles, keeping as close to the rib as possible to avoid 
wounding the intercostal artery, which lies close to its lower edge. The rib is 
then divided either with a cutting forceps like Estlander's, or a Gigli saw. The 
rib, having been divided at one end of the incision, is then lifted up, the pleura 
stripped off, and divided at the opposite end. 

Should the intercostal artery bleed, and it is often sufficiently large to spurt 
quite actively, it can be caught with a haemostatic forceps and secured with a 
ligature if necessary. This is safer than to trust to packing, on account of the 
lack of support due to the removal of the rib. After the incision is completed, 
the pleura is incised and the tube introduced. In ligating the intercostal artery, 
care should be taken not to include the nerve which lies close to but below it; that 
is, farther away from the rib. 

THE PERICARDIUM. 

The pericardium is composed of fibrous tissue lined with a serous membrane. 

When affected by inflammation the amount of fluid contained in it becomes 
increased and it becomes distended and may interfere with the functions of the heart 
and adjacent structures. 

If the efiusion is serous it is sometimes drawn off by puncture; if it is purulent 
drainage is instituted. 

The pericardium in shape is somewhat conical. Its base rests on the central 
tendon of the diaphragm and its apex envelops the great vessels, as they emerge 
from the base of the heart, for a distance of 4 to 5 cm. The attachment to the 
diaphragm is most firm at the opening of the inferior vena cava. As the fibrous 
layer of the pericardium proceeds upward it becomes lost in the fibrous tissue 
(sheath) covering the great vessels. This is continuous above with the deep cervical 
fascia, especially with its pretracheal layer. Anteriorly the pericardium is attached 
above and below to the sternum by the so-called sternopericardiac ligaments (Fig. 218). 

In front of it above are the remains of the thymus gland and triangularis sterni 
muscle of the left side from the third to the seventh costal cartilages. The internal 
mammaiy arteries, running down behind the costal cartilages about a centimetre 
from the edge of the sternum above and somewhat more below, are separated from 
the pericardium by the edges of the lungs and pleurae, these latter reaching nearly or 
quite to the median line. The triangularis sterni muscle also lies beneath the artery 
and farther from the surface. As the left pleura slopes more rapidly toward the side 
than does the right there is a small portion of the pericardium uncovered by the pleura 
at about the sixth intercostal space close to the sternum. The incisura of the left 
lung leaves a space where the pericardium is separated from the chest-walls only by 
the pleura. 

On each side the pleura and pericardium are in contact, with the phrenic nerves 
between them. Posteriorly the pericardium lies on the bronchi, the oesophagus, and 
the thoracic aorta. 



202 



APPLIED ANATOMY. 



Owing to the fibrous nature of the pericardium it will not expand suddenly. 
While only about a pint of liquid can be injected into the normal pericardia] cavity 
after death, if a chronic effusion exists in a living person as much as three pints may 
be present. 

Sudden effusion occurring in the living patient will cause obstruction of the cir- 
culation at the base of the heart; it may by pressure on the bronchi at the bifurcation 
produce suffocative symptoms and by pressure on the oesophagus difficulty in swallow- 
ing. The lungs are displaced laterally, and the stomach and liver downward. The 
largest effusions are slow in their formation. 

Pressure on the left recurrent laryngeal nerve as it winds around the aorta 
sometimes produces alteration or loss of the voice. 

In children, according to Osier, the praecordia bulges and the anterolateral region 
of the left chest becomes enlarged as does also the area of the cardiac dulness. 

Paracentesis of the Pericardium. — Tapping the pericardium by means of a 
trocar or aspirating needle must be carefully done, or the pleura may be punctured. 




Fig. 2i8. — View of the pericardium, slightly distended, and its relations to the bony thorax. 



The part of the pericardium in contact with the chest-wall which is never covered 
by pleura is small. It embraces the space between the two pleurae from the fourth 
to the seventh ribs. This may be defined by three lines, one in the midline, another 
from the middle of the sternum opposite the fourth rib to the costosternal junction 
of the seventh rib, and a third joining these two passing through the articulation of 
the xiphoid cartilage (Fig. 219). 

The left pleural sac may be i cm. distant from the left edge of the sternum. 
Thus it is seen that there is hardly a point where a needle can be introduced 
with the certainty of avoiding the pleura. The safest point is probably close to the 
left edge of the sternum in the sixth interspace. This interspace may not extend 
to the sternum, but even if the cartilages are in contact a needle could probably be 
introduced at this point. As the pericardium is distended it carries the lungs and to 
a less extent the pleura outwards and increases the area available for puncture both 



THE PERICARDIUM. 



203 



upward and downward as well as to the sides. When greatly distended the peri- 
cardium may reach to the first interspace above, 2.5 cm. (i in.) to the right of the 
sternum, to the seventh cartilage below, and to the left nipple line or even beyond. 
The arching of the diaphragm causes a sternophrenic sinus behind the sternum anal- 
ogous to the costophrenic sinus at the lower edge of the chest. This becomes dis- 
tended by pericardial effusions in the same manner as does the costophrenic sinus in 
pleural effusions. A puncture in the sixth space close to the left edge of the sternum 
enters this sinus. The increased area in cases of distention from pericardial effusions 
has led Osier to advise tapping in the fourth interspace, either at the left sternal 
margin or 2.5 cm. from it, or at the fifth interspace 4 cm. (i}4 in.) from the sternal 
margin ; or bv thrusting the needle upward and backward close to the costal margin 
in the left costoxiphoid angle. 

It is important to avoid wounding the internal mammary artery, which is usually 




Fig. 219. — Paracentesis of the pericardium. 



nearer to the sternum above (0.5 to i cm. to its outer side) and farther from it (2 to 
3 cm. ) below. 

The danger of wounding the pleura in aspirating with a needle has probably 
been overestimated, but when drainage is to be employed the danger is certain. 

Drainage of the Pericardium. — To drain the pericardium requires the 
removal usually of at least one of the costal cartilages. A drainage-tube can some- 
times be introduced by first making a short incision in the fifth or sixth interspace 
close to the left edge of the sternum, then puncturing the pericardium, dilating the 
puncture with forceps, and introducing the tube. The costal cartilages usually lie so 
close together as to interfere with the proper introduction of a tube, hence the neces- 
sity of resection. A flap may be made or a straight incision. The latter is some- 
times made over the fifth costal cartilage, which is then resected. If desired the 
sixth and seventh cartilages are also removed and even a piece of the left edge of the 
sternum. The intercostal muscles having been raised, the cartilages are removed. 



204 APPLIED ANATOMY. 

When the internal mammary artery is seen lying beneath, it is to be either ligated 
or drawn to one side. The triangularis sterni muscle is either incised or drawn to 
the outer side along with the edge of the left pleura. The pericardium can then be 
lifted with forceps and incised and the drainage-tube introduced. 

THE HEART. 

In size the heart is somewhat larger than the clenched fist. It measures 12.5 
cm. (5 in.) in length, 7.75 cm. (3>^ in.) in width, and 6.25 cm. (2>^ in.) in thick- 
ness. Its weight in the adult male is 250 to 300 Gm. (8 to 10 oz. ), in the female 
it is 60 Gm. (2 oz. ) less. 

It lies enclosed in its pericardium in the middle mediastinum between the 
sternum (from the upper edge of the third costal cartilage to the sternoxiphoid artic- 
ulation) in front, and the bodies of the fifth, sixth, seventh, and eighth thoracic ver- 
tebrae behind. Laterally it reaches from two centimetres to the right of the sternum 
nearly to the left nipple line. On each side of it are the lungs, from which it is 
separated by the pleurae and pericardium with the phrenic nerves between. Above 
are the great vessels and below it rests on the central tendon of the diaphragm. 

In shape the heart resembles an acorn, the atria {aiiricles), forming the upper 
right portion and the ventricles the lower left portion. It lies with its right side 
resting on the diaphragm and its apex pointing forward and to the left. 

For convenience one speaks of a base, an apex, a right border, a lower border, 
and a left border. 

OUTLINES OF THE HEART. 

The base of the heart is opposite the upper border of the third costal cartilage. 
It is here that the superior vena cava ends and the aorta begins. It extends from 
1.25 cm. {% in.) to the right of the sternum to 2.5 cm. (i in.) to the left of the 
sternum. 

The right border of the heart extends from 1.25 cm. (^ in.) to the right of the 
sternum at the upper border of the third costal cartilage in an outwardly curved line 
to the junction of the seventh rib and the sternum. In the fourth interspace it may 
reach 2.5 cm, (i in. ) beyond the right edge of the sternum. 

The lower border passes from the seventh right chondrosternal junction across 
the sternoxiphoid joint outward in the fifth interspace to the apex beat, which is 4 
to 5 cm. {i}4. in. to i ^ in. ) below and to the inner side of the nipple and about 
8.75 cm. {2>% in.) to the left of the median line. This marks the extreme left limit 
of the heart. In children the apex is higher — it is in the fourth interspace. In old 
people it is lower. 

The left border arches upward from the apex beat, as just given, in an inward 
and upward direction to 2.5 cm. (i in.) to the left of the sternum at the upper border 
of the third costal cartilage. 

The atrio- (auriculo-) ventricular groove or line of junction between the atria 
(auricles) and ventricles runs from the sixth right chondrosternal junction upward 
and to the left to the third left chondrosternal junction. The atria lie above and to 
the right of this line and the ventricles below and to the left. 

The right atrium (auricle) and right ventricle lie anteriorly and the left atrium 
and left ventricle lie posteriorly. In the right atrioventricular groove runs the right 
coronary artery. As it lies on the anterior portion of the heart it is liable to be injured 
in stab-wounds and give rise to fatal bleeding, as may also the interventricular 
branch of the left coronary artery as it passes down near the left border of the heart 
between the right and left ventricles. 

The Portio7t of the Heart Uncovered by Lung-tisstce. — When the lungs are 
distended the right lung covers the heart to the median line. The left lung leaves 
the median line at the level of the fourth costal cartilage and curves outward and 
downward to about the apex beat in the fifth interspace, 2.5 cm. to the inner side of 
the nipple line. At this point a small piece of the lung, the lingula, sometimes 
curves around in front of and below the extreme tip of the heart. As the air leaves 
the lungs they retract and their anterior borders hardly reach the edges of the sternum. 



THE HEART. 



205 



Area of Cardiac Dulness.— The area of cardiac dulness corresponds to the 
area uncovered by king and in contact with the chest-wall. This is the area of abso- 
lute dulness. It begins opposite the fourth costal cartilage and extends down the 
sternum, between the median line and left edge, to the liver dulness below opposite 
the sixth costal cartilage. Toward the left side it arches from the fourth left costo- 
sternal junction to the apex beat. The area of so-called relative dulness caused by 
overlapping of the lungs extends along the right edge of the sternum to opposite the 
upper border of the third rib above, and to the left follows parallel to the left border of 
the heart to the tip of its apex. Below it blends with the liver dulness (Fig. 221). 

The area of cardiac dulness may be increased not only by the enlargement of the 
heart itself but by pericardial effusions and disease such as aneurism of the great vessels. 

In an early stage of pericardial effusion and also in aneurism there may be an 




Fig. 220. — Relations of the heart, its valves, and the great blood-vessels to the surface of the chest. 

extension of the area of dulness upward. In a later stage of pericarditis the lateral 
area of dulness becomes increased. 

Cardiohepatic Angle (Ebstein).— This is the angle formed by the right 
border of the heart as it meets the liver. It is a more or less resonant area in the 
fifth right intercostal space. Below it is the liver dulness and above and towards 
the median line is the heart. 



VALVES OF THE HEART. 

There are two types of valves in the heart: the bicuspid {mitral^ and tricuspid 
between the atria (auricles) and ventricles, and the two sets of semilunar valves at 
the entrance of the pulmonary artery and aorta. (See Fig. 220.) 

The bicuspid valve is the most important and is the deepest seated. It lies 
at the edge of the left border of the sternum opposite the fourth costal cartilage. 
It separates the left atrium and ventricle and lies nearly transversely. 



2o6 APPLIED ANATOMY. 

The tricuspid valve lies in the middle of the sternum opposite the fourth 
intercostal space. It runs obliquely downward and to the right from the third left 
intercostal space to the fifth right costal cartilage. It separates the right atrium and 
ventricle. 

The pulmonary semilunar valve lies opposite the sternal end of the third left 
costal cartilage. It is the most superficial valve and the one highest up on the ster- 
num. It prevents regurgitation of the blood into the right ventricle from the lungs. 

The aortic semilunar valve lies under the left side of the sternum about level 
with the lower edge of the third costal cartilage. It is just below and to the right of 
the pulmonary valve, and above and to the left of the bicuspid valve. 

Location of Valvular Sounds. 

The sounds produced by the closure of the valves do not correspond with the 
position of the valves, but are as follows. 

The bicuspid sound is heard most distinctly at the apex of the heart as far 
inward as the parasternal line and as high as the third interspace. It is transmitted 
around the chest toward the axilla. 

The tricuspid sound is best heard at the left sternal border between the fifth 
and sixth costal cartilages (Tyson). 

The pulmonary sound is best heard in the second interspace to the left of the 
sternum; the cartilage above is called the pulmonary cartilage. 

The aortic sound is best heard in the second right intercostal space and the 
cartilage above is called the aortic cartilage. The aortic sounds are transmitted up 
the neck in the direction of the great blood-vessels. 

VARIATION IN SIZE AND POSITION OF THE HEART. 

The heart becomes enlarged both by being dilated and by being hypertrophied, 
usually both conditions are present; and its position is often changed by disease both 
of itself and of adjacent organs. It is apt to enlarge unequally. In emphysema and 
bicuspid regurgitation the right side becomes enlarged, the pulmonary circulation 
being impeded. In aortic disease, arteriosclerosis, muscular exertion, or any cause 
impeding the course of the blood through the arteries there is produced an enlarge- 
ment of the left side of the heart. 

The average weight of the healthy heart is in the male 280 Gm. (9 oz. ), and in 
the female 250 Gm. (8 oz. ). These may be doubled in cases of enlargement. 
When the heart is enlarged the apex beat changes its position; it may occupy the 
sixth, seventh, or eighth interspace instead of the fifth, and may be as far as 5 to 7.5 
cm. (2 to 3 in. ) to the left of the nipple line. 

When it enlarges upward, instead of the absolute dulness beginning opposite the 
fourth costal cartilage, it is opposite the third or even the second interspace. Toward 
the right side the absolute dulness may extend a couple of centimetres beyond the 
right edge of the sternum, instead of being near its left edge as is normal. 

The heart is readily displaced by pressure from the surrounding structures. If 
there is abdominal distention by gas or ascites, or if the liver or spleen is enlarged, 
the heart is pushed upward. Enlargement of the liver may likewise depress the 
heart, if the patient is in an upright position, by the weight of the liver dragging it 
down. Aneurisms of the arch of the aorta, tumors, or emphysema may also depress 
it. In the aged the apex beat may be normally in the sixth interspace. 

Lateral displacement occurs in cases of pleural effusion. Osier says (" Pract. of 
Med.," p. 594), this is not due to a twisting of the heart on its axis but to a positive 
lateral dislocation of the heart and pericardium. Pneumothorax or tumors on one side 
may also push the heart toward the opposite side. It may be pulled to one side by 
pleural adhesions and in those cases of fibroid phthisis in which the lung becomes 
markedly retracted. Abscess or tumors of the mediastinum also displace it. 

The position of the pulsation of the heart is not always an indication of the posi- 
tion of the apex. In pleural effusion the pulsation may be one, two, or three inter- 
spaces higher than normal, while the apex itself may not be elevated. 



THE HEART. 



207 



WOUNDS OF THE HEART. 

Wounds of the heart are usually immediately fatal, but sometimes they are not 
so. The pleurae are very liable to be wounded at the same time. The right ven- 
tricle, on account of Iving anteriorly, is the part most often involved. The atria lie 
more posteriorly and are most apt to be wounded in stabs through the back. Not 
only may the substance of the heart itself be injured but also its blood-vessels. The 
right coronary artery lying in the atrioventricular groove and the anterior interven- 
tricular branch of the left coronary running between the two ventricles anteriorly are 
the vessels most liable to injury. Owing to the heart being enclosed in the peri- 
cardium, — a closed sac, — if blood accumulates in it the action of the heart is inter- 




FiG. 221. — Percussion area of the liver and heart. The light shaded area represents the extent of deep or relative 
dulness and the dark snaded area that of superficial or absolute dulness. 

fered with. To avoid this occurrence, wounds bleeding externally should not be 
closed, or distention of the pericardium may ensue. 

Wounds of the heart have been sutured successfully. In order to reach the 
heart, a portion of the chest-wall would have to be resected and turned to one side 
as a flap. This will probably require the opening of the pleural cavity. The pleurae 
will in all likelihood already have been involved and found to be filled with blood, as 
has occurred in at least one case. 

A knowledge of the exact outlines of the heart as already given will often 
enable one to decide as to whether a wound involves the heart or not. 



2o8 APPLIED ANATOMY. 



THE AORTA. 

The aorta, as it leaves the left ventricle, begins under the left portion of the 
sternum opposite the lower border of the third left costal cartilage. This is the 
location of the aortic semilunar valves as already given. It passes upward toward 
the right for 5 cm. and then forms an arch, extending backward toward the left, to 
reach the spine on the left side of the body of the fourth thoracic vertebra. The 
arch is continued down in front of the spine as the thoracic aorta and pierces the 
diaphragm in the median line, between the two crura of the diaphragm, opposite the 
twelfth thoracic vertebra. 

The ascending aorta begins behind the left half of the sternum on a level 
with the lower border of the third costal cartilage. It proceeds upward toward the 
right until it reaches the level of the lower border of the right second costal cartilage, 
where the arch begins. 

Immediately above its commencement it has three enlargements, called the 
sinuses of the aorta (Valsalva), which correspond to the semilunar valves. Of 
the three semilunar valves two are anterior and one is posterior. From behind the 
two anterior valves come the right and left coronary arteries. 

Beyond the valves, in the upper right portion of the arch, the aorta is again 
dilated, forming the great sinus of the arch of the aorta. 

The right limit of the aorta is about even with the right edge of the sternum; 
sometimes it projects slightly beyond. When it does so it is liable to be wounded by 
a stab in the second interspace close to the edge of the sternum. On account of the 
proximity of the aorta to the second interspace, it is here that the stethoscope is placed 
to hear aortic murmurs. The aorta at this point is covered only by the thin border of 
the right lung and pleura and the slight remains of the thymus gland. Below, its com- 
mencement is overlapped on the right by the auricula dextra (right auricular appendix) 
of the atrium and on the left by the commencement of the pulmonary artery. 

The ascending aorta is liable to be the seat of aneurism. It may involve either 
the lower portion in the region of the sinuses or the region of the great sinus at its 
upper right anterior portion. 

If the aneurism enlarges anteriorly it will show itself first in the second or third 
interspace. It will bulge the ribs outward in this region. The right lung will be 
pushed outward and the two layers of the pleura pressed together. It may break 
externally through the surface or open into the pleural cavity. If it tends to the 
right it presses on the descending cava and right atrium, thus interfering with the 
return of the blood from the head and neck and both upper extremities. If it en- 
larges to the left or backward it may press on the right pulmonary artery and 
interfere with the free access of blood to the lungs. 

The first portion of the aorta is not united with the pericardium, but simply 
loosely covered by it, so that this portion of the arch is weaker than the other por- 
tions, and rupture, with extravasation of blood into the pericardial sac, is not uncom- 
mon. An aneurism may also rupture into the superior vena cava. 

The arch of the aorta passes anteroposteriorly from the upper border of the 
second right costal cartilage in front to the left side of the body of the fourth thoracic 
vertebra behind. It is about 5 cm. (2 in.) long. Its under surface is level with the 
angle of the sternum (angle of Ludwig), opposite the second costal cartilage. Its 
upper surface rises as high as the middle of the first piece of the sternum, which is 
opposite the middle of the first costal cartilage, about 2.5 cm. (i in.) below the top 
of the sternum. 

Relations. — In front of the arch the right lung and pleura cover it slightly, but 
the left more so; the remains of the thymus gland is between them. The left superior 
intercostal vein crosses its upper portion to empty into the left innominate vein. The 
left phrenic and vagus nerves also cross it, the phrenic being the farther forward and 
the vagus crossing almost in front of the point of origin of the left subclavian artery. 
Behind lie the trachea, oesophagus, and thoracic duct, also the left recurrent laryn- 
geal nerve. The bifurcation of the trachea is directly behind and below the lower 
portion of the arch and the left bronchus passes beneath it. The oesophagus lies 



THE AORTA. 



209 



compressed between the trachea and vertebroe with the thoracic duct immediately to 
the left. The left recurrent laryngeal leaves the pneumogastric on the front of the 
arch, then winds around it and ascends between the trachea and oesophagus to reach 
the larynx above. Above, from the upper surface of the aorta, are given ol? the 
innominate, left carotid, and left subclavian arteries. The left innominate vein crosses 
above its upper edge to unite with the right innominate to form the superior cava. 
Below is the left bronchus coming of? from the bifurcation of the trachea, and wind- 
ing around the arch is the left recurrent laryngeal nerve. Beneath the arch and 
in front of the bronchi are the right and left pulmonary arteries. From the latter the 
ductus arteriosus goes to the arch. The cardiac branches of the pneumogastric and 
sympathetic nerves lie on the anterior, inferior, and posterior sides of the arch 



Vagus nerve. 

Common carotid 

artery 

Internal jugular vein 

Subclavian vein 

Innominate artery 

Right recurrent 

laryngeal nerve 

Right innominate 

vein 

Phrenic nerve 



Descending vena 
cava 



Aorta 



Right auricle 
(atrium) 



Right coronary 
artery 




Vagus nerve 
■Common carotid artery 
Internal jugular vein 
Subclavian vein 

Left innominate vein 
Phrenic nerve 



eft recurrent 
laryngeal nerve 

Ductus arteriosus 
Pulmonary artery 
Left bronchus 
Pulmonary veins 



Left coronary artery 
Left ventricle 



Right ventricle 



Fig. 222. — Heart and great blood-vessels. 

The ductus arteriosus at birth is about i cm. long and runs from the pulmo- 
nary artery to the arch of the aorta below the left subclavian artery. It serves in the 
fcetus to carry the blood from the trunk of the pulmonary artery direct to the aorta 
instead of passing into the lungs. When, after birth, the lungs are used the ductus 
arteriosus becomes obliterated and is found later in life as a cord running to the 
under side of the arch of the aorta. Congenital defects in the heart are a frequent 
cause of death at birth and in infancy and childhood. They cause an undue mixture 
of the venous and arterial blood and give the surface a dusky, bluish hue, hence the 
term " blue baby " as applied to this condition. It is due to an absence of a part 
14 



2IO APPLIED ANATOMY. 

or the whole of the septa between the atria and ventricles; to a patulous condition of 
the foramen ovale of the right atrium ; and also to a jjersistent patulous condition of 
the ductus arteriosus. Children so affected, if they outlive infancy, usually die before 
reaching adult age. 

Aneurism. — This portion of the aorta is also a favorite seat of aneurism. The 
symptoms produced will depend of course on the direction which the tumor takes. 
If it tends anteriorly it would involve the lungs and pleurae and the phrenic and vagus 
nerves, also the sympathetic. The displacement of the left lung would be the more 
marked. Involvement of the recurrent laryngeal nerve might make a change in the 
voice, or there might be disturbances of the pupil of the eye due to implication of 
the sympathetic. 

Should the tumor enlarge posteriorly the pressure on the trachea would inter- 
fere with the breathing. If the tumor is large this pressure would involve the oesoph- 
agus and there might be difficulty in swallowing. Compression of the thoracic duct 
is said to have led to rapid wasting. 

If the aneurism bulges downward it impinges on the left bronchus, which may 
lead to its dilation and cause bronchorrhcca. A large tumor could also interfere with 
the flow of blood through the pulmonary arteries and so give rise to congestion and 
dyspnoea. 

An enlargement upward would involve the innominate and left carotid and 
subclavian arteries and also the left innominate vein. Interference with the arteries 
and veins of the neck and upper extremity frequently gives rise to changes in the 
pulse on the affected side and also to venous congestion or even oedema. Changes 
in the voice or even its loss also occur. The sac as it passes upward may show 
itself in the suprasternal notch. 

In all aneurisms of the arch cough is apt to be a prominent symptom. It is 
often paroxysmal. It is to be accounted for by pressure on the trachea or laryngeal 
nerves. Difficulty in breathing and swallowing may arise in deep-seated small tumors 
growing backward and downward. This may be somewhat relieved by sitting up or 
leaning forward, while reclining or lying on the back may be unendurable. 

The great amount of distress which these aneurisms of the arch of the aorta may 
give rise to is readily appreciated when one recalls that there is only a distance of 5 
or 6 cm. (2^^ in.) between the upper edge of the sternum and the anterior surface 
of the vertebral column, a space already filled with important structures. 

The Descending Aorta. — The remaining portion of the aorta, from the lower 
border of the fourth thoracic vertebra down, is called the desceyiding aorta. It is 
divided into the thoracic and abdominal portions. The thoracic aorta begins at the 
lower border of the fourth and ends at the lower border of the twelfth thoracic 
vertebra. At its beginning it lies on the left side of the vertebral column, but as it 
descends it comes somewhat forward but does not reach the middle line. It lies in 
the posterior mediastinum more toward the left side than toward the right. 

Relations. — In front above are the pericardium, the pulmonary artery, left bron- 
chus, left pulmonary veins, and oesophagus. Behind is the vertebral column. To 
the right are the oesophagus above, the vena azygos major, and the thoracic duct. 
To the left are the left lung and the pleura, which it grooves, and a quite small 
portion of oesophagus below. 

Aneurism., when involving the thoracic aorta, tends to cause absorption of the 
vertebrae and ribs, and to present posteriorly; as the space is not so restricted as is 
the case higher up the tumor has a freer opportunity to expand and the suffering is 
not so great nor are the symptoms so marked. It may rupture into the left pleura or 
oesophagus and may erode through the bodies of the vertebrae into the spinal canal. 

These aneurisms may exist many years and attain a large size. 



THE CESOPHAGUS. 



THE OESOPHAGUS. 

The oesophagus begins at the lower edge of the cricoid cartilage, opposite the 
lower border of the sixth cervical vertebra, and ends at the cardiac opening of the 
stomach, opposite the eleventh thoracic vertebra. 

It is 25 cm. (10 in.) long and begins 15 cm. (6 in.) distant from the teeth. In 
the neck it inclines to the left, hence oesophagotomy is performed on that side. It 
reaches the farthest point to the left at the level of the top of the sternum or oppo- 
site the second thoracic vertebra. It then inclines to the right, reaching the median 
line opposite the fifth thoracic vertebra. It then again inclines to the left, to pierce 
the diaphragm in front of the aortic opening and to the left of the median line opposite 
the tenth thoracic vertebra, and ends in the cardiac opening of the stomach entirely 
to the left of the median line and opposite the eleventh thoracic vertebra or tenth 
dorsal spine. In its passage through the diaphragm it is accompanied by the con- 
tinuation of the two vagi nerves. At its termination it grooves the posterior surface 
of the liver. 

Lumen. — The lumen of the oesophagus is narrowed at three points, (i) its com- 
mencement; (2) where it crosses the aorta and left bronchus; and (3) near its end 
as it passes through the diaphragm. 

The average diameter of the lumen is 2 cm., which at the upper and lower 
constrictions is reduced to 1.5 cm. The middle constriction is not quite so marked. 
The lower constriction is most marked at the point of the passage of the oesophagus 
through the diaphragm; it enlarges slightly as it enters the stomach. This part of 
the oesophagus is quite distensible. The next most distensible part is opposite the 
left bronchus. This is on a level with the middle of the first piece of the sternum and 
the third thoracic vertebra. The upper constriction at the cricoid cartilage is the 
least distensible part of the tube, so that a body passing it may pass entirely down. 

In both living and dead bodies the lumen of the oesophagus is sometimes open 
and sometimes closed. In the neck the pressure of the soft parts usually keeps it 
closed, but frozen sections of the dead body show it sometimes closed and sometimes 
open. Mikulicz in using the oesophagoscope has found the lumen open in the living 
patient and been able to see down the remainder of the tube when the instrument has 
only been passed beyond the second constriction. 

In passing an oesophageal bougie, one should not be used of a larger diameter 
than 18 mm. (^ in.). It will enter the oesophagus opposite the lower border of the 
cricoid cartilage about 15 cm. (6 in.) from the teeth. It will pass the second con- 
striction 7 cm. (2^ in.) farther on, opposite the middle of the first piece of the 
sternum or 2. 5 cm. ( i in. ) below its upper border, and meet the third constriction 
15 cm. (6 in.) lower down, or 37 cm. (14.4 in.) from the teeth, and enter the stomach 
3 cm. below, or 40 cm. (16 inches) from the teeth and opposite the eleventh dorsal 
vertebra. 

Relations. — In the neck the oesophagus rests on the longus colli muscle and 
vertebrae behind and has the trachea in front. On the left side it lies close to the 
carotid sheath, the lobe of the thyroid gland, and the thoracic duct. The left recurrent 
laryngeal nerve is in closer relation to it than the right on account of the latter 
coming over from the right subclavian artery. The left nerve lies on its anterior 
surface near the left edge. The right carotid artery lies farther from it than does 
the left. The left inferior thyroid artery is also in closer relation to it than the right 
on account of the inclination of the oesophagus to the left side. 

In the thorax it passes through the superior mediastinum between the trachea and 
its bifurcation in front and the aorta behind. 

In front it has the bifurcation of the trachea and encroaches more on the left 
than on the right bronchus. The arch of the aorta and the left carotid and subclavian 
arteries also pass in front of it and in the posterior mediastinum the pericardium and 
diaphragm are anterior to it. 

Posteriorly, above it rests on the spinal column, but below the bifurcation of 
the trachea the aorta intervenes. 



212 



APPLIED ANATOMY. 



Vi- 



Laterally it is in relation with the left pleura above and the right below and the 
vena azygos major runs along its right side posteriorly. The arch of the aorta winds 
around its left side at the root of the lung. The right vagus nerve runs down pos- 
teriorly and the left anteriorly, forming a plexus on its surface. 

Dilatation and Diverticula. — In certain rare cases the 

/ oesophagus becomes dilated ; this may involve the whole length 

/ of the tube or only its lower end. Obstruction low down may be 

( ! a cause. It has been known to accompany a largely dilated aorta 

which pressed the oesophagus against the diaphragmatic opening 

and so hindered the passage of food. Regurgitation of food is a 

prominent symptom and liquids may regurgitate from the stomach 

and even enter the mouth. 

Diverticula are usually acquired and are but seldom con- 
genital. The point of junction with the pharynx just behind the 
cricoid cartilage is the most frequent seat. A sac is formed which 
descends posteriorly behind the part of the tube below and as it 
increases in size it presses forward and may obstruct its lumen. 
Obstruction from foreign bodies, stricture, or disease of the cardiac 
end of the stomach may be a cause. Vomiting is a prominent 
symptom and the vomited material does not show any evidences of 
iM digestion or the presence of acid. The existence of a tumor which 

forms only on deglutition and which can be emptied by pressure 
is said to be pathognomonic of an oesophageal diverticulum. 

Diverticula have been treated by washing out with a stomach- 
tube, by excision, or if emaciation is rapid and marked by doing 
a gastrostomy. 

Carcinoma and Stricture. — Carcinoma is usually of a flat- 
celled epitheliomatous type and may surround the oesophagus like 
a ring. The walls are thickened, a tumor forms, and the internal 
surface may become ulcerated. Stricture of the affected part may 
lead to the formation of a dilation or diverticulum above, and ulcer- 
ation and abscess may perforate and enter surrounding organs. 

Dyspnoea may arise from pressure on the air-passages and pus 
may even penetrate them. Hemorrhage is also sometimes a symp- 
tom. It may come either from the inside or outside. In the latter 
case it may come from the large vessels in the neighborhood. 

Septic inflammation may also be set up in the adjacent pleurae 
and lungs. 

Foreign Bodies. — Foreign bodies may become impacted 
at any part of its course; this is particularly the case if they are 
hard and rough with irregular outlines. If they are smooth and 
soft and more or less rounded they are apt to lodge at the con- 
stricted parts of the tube. These points are, as already stated, at 
its commencement, where it crosses the aorta and left bronchus, 
and where it passes through the diaphragm. The upper con- 
striction is 1.5 cm. (or f in.) in diameter, and is least distensible. 
It will dilate to the width of 2 cm. , and thus will allow a body of 
about ^ inch diameter to pass. The two lower constrictions are 
more distensible and a body that passes the oesophagus can usually 
pass the ileocaecal valve, so that the upper end of the oesophagus 
acts as a gauge to prevent the entrance of substances too large for 
the rest of the alimentary tract. The bodies which become lodged 
are usually those which have been pushed down beyond the open- 
ing of the oesophagus by the contraction of the muscles of the 
pharynx, and then on account of their irregular form become 
caught by the contraction of the tube below. With the head mod- 
erately extended, the first constriction will be 15 cm. (6 in.) from 
the teeth. A foreign body at this point will be opposite the cricoid cartilage at the 
level of the sixth cervical vertebra. 



Fig. 223. — The oesopha- 
gus. From a plaster cast. 



THE CESOPHAGUS. 



213 



The second constriction is opposite the middle of the first piece of the sternum. 
This is 7 cm. (2^ in. ) below the cricoid cartilage. Therefore a foreign body lodged 
just above it would be just below the top of the sternum. 

It would be felt by the probe 22 cm. (8| in. ) from the upper teeth and if cesopha- 
gotomy was performed it could usually be reached from the wound in the neck. 

The third constriction is 15 cm. (6 in.) below the second, or 37 cm. (i4i in.) 
from the teeth, and is accessible from the stomach. This third constriction is more 



Left common 
carotid 

Vagus nerve 

Int. jugular vein 

Inf. thyroid artery 

Vertebral artery 

Thoracic duct 

Phrenic nerve 
Recurrent laryn- 
geal nerve 
Subclavian artery 

Bronchial artery 
Pulmonary 

artery / , 
Left vagus nerve 

Left bronchu 

Pulmonary vein 
Aorta 

Thoracic duct 

Vena azygos 
major 




Int. jugular vein 

Vagus nerve 

Common carotid artery 

Inf. thyroid artery 

Vertebral artery 

Trachea 

Recurrent laryngeal 

nerve 

CEsophagus 

Right vagus nerve 
Phrenic nerve 

Vena azygos 

major 

Right bronchus 

Right pulmonary 

artery 

Pulmonary vein 



Fig. 224. — Posterior view of the oesophagus, showing its relation to the surrounding structures. 



distensible than the two above it. Maurice H. Richardson was able, after introducing 
the hand into the stomach, to put two fingers into the cardiac opening from below, 
and so dislodge some impacted false teeth. 

Foreign bodies are dangerous on account of the ulceration into the various organs 
which they cause and also on account of pressure. Pressure on the left bronchus and 
trachea has caused suffocation. 



214 APPLIED ANATOMY. 

Ulceration may cause fatal hemorrhage by involving the carotid arteries, more 
likely the left, the inferior thyroids, the innominate, and even the aorta itself lower 
down. Low down in the chest the pericardium is in front of the oesophagus, and 
has been perforated. On the left side above and the right side below, the pleura 
have been perforated and the lungs involved. Abscesses may occur from the ulcer- 
ative process and they are particularly dangerous, as the distance between the upper 
portion of the sternum and anterior portion of the bodies of the vertebra is so small 
that compression of the air-passages and suffocation is readily produced. 

THE THORACIC DUCT. 

The thoracic duct carries not only lyjnph but also chyle which is emptied into the 
venous system and goes to nourish the body. Therefore a wound of the duct with 
the escape of its fluid may result fatally from inanition. The lymph coming from all 
parts of the body is collected into two ducts, the right lymphatic duct and the thoracic 
duct. Of these two the right lytnphatic dtid is the smaller. It collects the lymph 
coming from the right side of the head and neck, right upper extremity, right side of 
the thorax and the upper convex surface of the liver. The several lymphatic branches 
unite to form a duct, one to two centimetres long, which empties into the venous 
system at the junction of the right internal jugular and subclavian veins. At its point 
of entrance it is guarded by a pair of valves. As this duct contains no chyle, and 
lymph of only a portion of the body, wounds of it have not proved serious. 

The thoracic duct is much larger and more important. It begins on the 
bodies of the first and second lumbar vertebrae to the right of the aorta in the 
cisterna {receptaculurii) chyli. 

The cisterna or receptaculum is 5 to 7.5 cm. long and 7 mm. wide. It receives 
not only the lymph from the parts below but also the chyle from the intestines. It 
passes through the aortic opening in the diaphragm with the aorta to the left and the 
vena azygos major to the right. In the posterior mediastinum it lies on the bodies 
of the seven lower thoracic vertebrae, with the pericardium, the oesophagus, and the 
arch of the aorta in front. The thoracic aorta is to its left and the vena azygos major 
and right pleura to its right. Above the fifth thoracic vertebra it ascends between the 
oesophagus and left pleura, behind the first portion of the left subclavian artery. 
On reaching the level of the seventh cervical vertebra it curves downward over the 
left pleura, subclavian artery, scalenus anticus muscle, and vertebral vein to empty 
at the junction of the internal jugular and left subclavian veins. It passes behind 
left internal jugular vein and common carotid artery. At its termination it lies 
just external to the left sternoclavicular joint and just below the level of the upper 
border of the clavicle. A punctured wound at this point would injure the duct. 

Accompanying the veins of the neck are numerous lymph-nodes which not 
infrequently become enlarged and require removal. It is in operating on these nodes 
that wounds of the thoracic duct have been most often produced. When divided, its 
lumen has appeared to be of the size of a "knitting needle." In some instances the 
thin walls of the duct have been ligated. In other cases of injury either the oozing 
point has been clamped with a haemostatic forceps which has been left in position for 
a day, or else the wound has been packed with gauze. Recovery usually ensues. 



THE THORACIC DUCT. 



215 



Internal jugular vein 



Trachea 

Vertebral vein 

Right lymphatic duct 

Subclavian vein 
I. rib 

Right innominate vein 



CEsophagus 



Vena azygos 



Right lumbar lymph trunk 



Crest of ilium 



Thoracic duct 



Aorta 




Left common carotid artery 

Left innominate vein 

Thoracic duct 

Left subclavian vein 

Scalenus anticus 

Left subclavian artery 

Thyroid axis 

L rib 

Vertebral artery 



Intercostal arteries 



Receptaculum chyli 
Intestinal lymph trunk 



Left lumbar lymph trunk 



Crest of ilium 



Fig. 225. — Dissection of posterior body-wall, seen from in front, showing thoracic duct and right lymphatic duct; 
veins have been laterally displaced to expose the terminations of the thoracic duct. (Piersol.) 



2l6 



APPLIED ANATOMY. 



THE UPPER EXTREMITY. 

Morphology. — The human skeleton consists of two parts, called the axial 
skeleton and the appendicular skeleton. 

The axial skeleton embraces the bones of the head, the 
spine, the ribs, the hyoid bone, and the breast bone. In the 
spine are included not only the vertebrae of the cervical, 
thoracic, and lumbar regions, but likewise the sacrum and 
coccyx. 

The appendiciilar skeleton embraces the bones of the limbs, 
or extremities, including the shoulder-girdle, formed by the 

scapula and clavicle, and the pelvic 
girdle, formed by the innominate bone 
(Fig. 226). 

Function. — The upper extrem- 
ity in man is an organ of prehension. 
As such, mobility is its chief charac- 
teristic. To permit of this mobility 
the bones and joints are many, and 
the latter are comparatively loose; 
the muscles, also, are both numerous 
and complex. Hence it is that slight 
injuries are frequently followed by 
considerable disturbance of function. 
They are readily produced and with 
difficulty repaired, either by nature 
or by art. Orthopaedic surgery has 
done much for the disabilities and de- 
formities of the lower extremities, but 
comparatively little for those of the 
upper. An artificial leg in many cases 
satisfactorily substitutes the natural 
one, but an artificial arm is compara- 
tively useless. 

The hand is the essential part 
of the upper extremity, and the rest 
of the limb is subsidiary. If the forearm were lack- 
ing and the hand were attached to the end of the 
humerus it would still be a very useful appendage, 
far more so than the stump which is left after the hand 
has been amputated. 

The extremities proper are joined to the trunk by 
what are called girdles. The upper extremity is 
attached through the medium of the shoulder-girdle 
and the lower extremity by the pelvic girdle. The 
interposition of these girdles adds to the mobility of 
the extremities, and as the upper extremity is more 
mobile than tho lower we find the shoulder-girdle com- 
posed of two bones instead of one as in the pelvic 
girdle ; also, as the lower extremity bears the weight 
of the body it requires strength in addition to mobility, 
hence we find that it is joined to the trunk by a single 
big strong bone, the innominate, instead of by two 
comparatively slight, narrow bones like the clavicle 
and scapula which form the shoulder-girdle. 

The extremities are termed appendicular because 
.r./,'-^-V^-T^^'^^'^^^°\^'T}'T-^ they are simply appendages to the essential part, 

and trunk tormiiiK the axial skeleton , • 1 . 11 1 1 1- '..U 

and those of the upper and lower ex- which IS the head and trunk; z. persou can live witn- 

fremities constituting the appendicu- ^ . •, • 

lar skeleton. out extremities. 




THE SHOULDER-GIRDLE. 



217 



THE SHOULDER-GIRDLE. 

The upper extremity is joined to the trunk by the shoulder- girdle, which is 
composed of the clavicle and scapula. The main moxements are anteroposterior, 
as in swinging the arm, those of abduction and adduction, as in raising and lower- 
ing it sidewise, and rotation. 

The scapula is the more important bone; it is present in all mammals, and the 
humerus articulates with it. 

The scapula in the mole and many other animals may be a comparatively 
slender bone, but when, as in man^ it is necessary to rotate the arm, then the 



Acromion process 



Clavicle 



Spine 



Scapula 




Fig. 227. — Shoulder-girdle of man. 

scapula is large so as to form a strong support for the infraspinatus, supraspinatus, 
teres minor and major, and subscapularis muscles. 

The clavicle is developed mainly from membrane, partly probably from carti- 
lage, and is the first bone in the body to ossify. It keeps the shoulder out away 
from the body and increases the range 
of motion of the upper extremity. It 
owes its existence to the function of 
abduction. Without a clavicle abduc- 
tion is practically wanting and when in 
man the clavicle is broken, he is tem- 
porarily reduced to the condition of those 
animals which have no clavicles; he is 
able to move the arm backward and for- 
ward but not to elevate it properly, and 
this is an important diagnostic symptom 
of that injury. 

The clavicle is lacking in the ungu- 
lates or hoofed animals. These have an 
anteroposterior movement, but little abduction. A horse or cow mo\'es its fore-legs 
back and forward, but not out away from the body. Hence its helplessness when 
these movements are essential. It is also lacking in seals and whales. In the 
carnivora, as the Hon and the tiger, which possess rudimentary clavicles, sufificient 
adducting power is present to enable them to hold their food while tearing it apart. 
In man, apes, bats, rodents, and insectivora the clavicle exists as a well-formed bone; 




Fig. 228. — Shoulder-girdle of man, showing how 
the clavicle acts as a prop to keep the shoulder out away 
from the chest. 



2l8 



APPLIED ANATOMY. 



hence they can raise the arm well out from the body and even higher than the 
shoulder. In the rodents, as the squirrel, they are enabled to hold a nut firmly in 
the paws while eating it. When, as in some of the lower orders, the function of 
abduction is all important, we find not only the clavicles present and, as in the 
common fowl, joined, forming the "wish-bone," but in addition, in birds, there is a 
precoracoid bone formed by the coracoid process, which is enlarged and continued 
forward to articulate with the sternum; thus in flying animals there are practically 
two clavicles on each side. 

Affections of the Shoulder. — The point of the shoulder projects well out 
from the side of the thorax. Hence it is frequently injured. As the force is resisted 




Scapula 



Sternum 



Fig. 229. — Shoulder-girdle in birds. Skeleton of an eagle, from the Wistar Institute: the clavicle, precoracoid, 
and scapula form the shoulder-girdle; the two clavicles have fused in the median line, forming what is commonly 
called the " wish-bone." 



by the bones, these receive the principal injuries and they are often broken. Frac- 
tures of the clavicle dispute with those of the radius the distinction of being the 
most numerous. Contusions produce more or less complete paralysis of the muscles, 
not infrequently through lesions of the nerves. The laxity of the joint favors the 
dislocations to which it is so frequently subject. It likewise becomes the seat of 
tuberculous disease requiring resection. Crushes of the arm sometimes require its 
removal at the shoulder-joint, and occasionally as the result of injury or disease opera- 
tions may be required on the axillary lymph-nodes, nerves, or blood-vessels. 

In order to determine the character and extent of injuries to the shoulder, its 
surface anatomy must be thoroughly known. In order to treat them, a knowledge 
of the deeper structures and their relation to one another is essential. 



THE SHOULDER-GIRDLE. 



219 



The landmarks of the shoulder are formed by the bones and muscles; hence a 
brief re\ie\v of their important characters will serve as a basis for the surface anatomy 
which follows. 

THE BONES OF THE SHOULDER. 

The bones entering into the construction of, and forming the basis on which the 
shoulder is constructed are the clavicle and scapula, forming the shoulder-girdle, and 
the humerus. 

The clavicle is a comparatively long and slender bone that acts as a prop to 
keep the point of the shoulder out from the trunk. The inner extremity is large and 
rests with its flat surface on the upper outer edge of the sternum, with the inter- 
position of a disk of tibrocartilage. Its outer extremity is flattened ; it articulates by 



Trapezius 




Deltoid 



Pectoralis major 



Fig. 230. — Right clavicle, upper surface. 



means of a gliding joint with the acromion process of the scapula, and it is connected 
with the base of the coracoid process beneath by ligaments. It is double curved, the 
large curve having its convexity forward and embracing the inner two-thirds of the 
bone, and the small curve having its concavity forward, forming the outer third. 

At the deepest part of the concavity of the anterior edge, about at the junction 
of its outer and middle thirds, is a small rough eminence called the deltoid tubercle 
because of the attachment to it of the deltoid muscle. At a corresponding point on 
the posterior and under surface of the bone is a prominent projection called the conoid 
tubercle ; to this is attached the conoid ligament. Running forward and outward 
from this tubercle on the under surface is a rough line which serves as the point of 



Pectoralis major 




Subclavius 
Fig. 231. — Right clavicle, under surface. 



Sternohyoid 



attachment of the trapezoid ligatnent. Both these ligaments are of importance in 
relation to the fractures of this bone. 

The middle third of the bone is its weakest part. Attached to the clavicle on 
its anterior surface are the deltoid muscle on its outer third and the pectoralis major 
on its inner half. On its posterior and upper surfaces are the trapezius at its outer 
third, and the clavicular head of the sternomastoid on its inner third. The subclavius 
muscle is attached to its under surface. It will thus be seen that there is a space equal 
to one-sixth of the length of the bone inferiorly and one-third of the bone superiorly 
which is free from muscular attachments, and it is here that it is most frequently 
fractured. 

The Scapula. — The scapula is spoken of as having a body, neck, spine, and 
acromion, glenoid, and coracoid processes; an upper, an anterior, and a posterior border; 
and an upper and a lower angle. It is not often spoken of as possessing a head, the 
glenoid process or that portion being sometimes so called in which the gleyioid cavity 
or fossa for the articulation of the humerus is situated. 



220 



APPLIED ANATOMY. 



The constriction surrounding the head of the scapula is known as the anatomical 
neck, in contradistinction to the surgical neck, which name has been given to that 
portion indicated by a Hne drawn through the suprascapular notch and passing 
beneath the spine and to the inside of the attachment of the long head of the triceps 
muscle just belo.w the lower edge of the glenoid cavity. 

The angles and borders and spine are important landmarks in physical diagnosis 
and the coracoid and acromion processes in injuries. 

In the upper border of the bone at its junction with the base of the coracoid 
process is a deep notch called the suprascapular notch {iyicisura scapulce), the supra- 



Deltoid 



Trapezius 
Supraspinatus 



Omohyoid 



Short head of 
biceps and coraco- 
brachialis 



Levator scapula^ 



Rhomboideus minor 



Infraspinatus 



Rhomboideus major 




Teres major 



Latissimus dorsj 



Fig. 232. — Scapula, showing muscular attachments. 



scapular nerve passes through it. The artery passes over it. From the edge of the 
bone just behind the notch arises the omohyoid muscle, an important guide in opera- 
tions on the neck. 

The body of the scapula on its under surface is flat and rests on the thorax from 
the second to the seventh and nearly to the eighth rib. Its movements on the chest 
are free and follow those of the arm. It rises and falls, glides forward and backward, 
and also rotates on an anteroposterior axis. 

When using any portion of the scapula as a landmark it is customary to have 
the arm hanging by the side; if it is otherwise the position of the bone will be 
changed, and the relations of its projections to the surrounding parts are altered. 
The scapula is sometimes fractured directly across its body below the spine. One 
should endeavor to fix in mind especially the relation of the acromion and coracoid 
processes to the head, with its glenoid cavity, and the rest of the bone. 



THE SHOULDER-GIRDLE. 



231 



Greater tuberosity. 

Lesser tuberosity and 

facet for subscapu- 

laris muscle 

Bicipital groove 



Surgical neck 




Fig. 233. — Anterior surf ace of upper end of humerus. 



The head is comparatively small and cup-shaped, with the glenoid fossa on its 
surface for the head of the humerus. It is joined to the body of the bone by a narrow 
constriction called the neck. Fractures through this neck are rare. Above and pos- 
terior to the glenoid fossa is the acromion process and spine of the scapula, and above 
and anterior is the coracoid process. 

The spine of the scapula runs upward and forward across the upper and posterioi 
surface of the bone. Its commencement . . , , 

, . , r 1 1 • 11 1 Anatomical neck 

at the posterior edge of the bone is called 
its root; this is over the fourth rib and 
opposite the third thoracic spine. The 
posterior edge of the scapula opposite 
the root of the spine projects backward, 
but this is not the superior angle, which is 
still higher up. The spine of the scapula 
ends anteriorly in the acromion process. 
This projects far beyond the glenoid cav- 
ity, overhangs the head of the humerus, 
and forms the point of the shoulder. It, 
as well as the rest of the spine, is subcu- 
taneous and is a valuable landmark. 

The acromion process is not so often 
fractured as one would expect. It articu- 
lates with the clavicle and the bones are 
not infrequently luxated at this point. 

The coracoid process projects 
forward underneath the clavicle to the 
upper and inner side of the head of the 
humerus. It is about 2.5 cm. (i in.) 
below the clavicle and just to the outer 
side of the junction of its middle and outer thirds. It lies just underneath the inner edge 
of the deltoid muscle, hence it is not always easily felt. It is almost never fractured, 
but is especially valuable as a landmark in injuries and operations on the shoulder. 

The two great hollows above and below the spine are the supra- and infraspinous 
fossa for the supra- and infraspinatus muscles. The angles are at the two extremities 

of the posterior border. The 
superior angle receives the in- 
sertion of the levator scapulae 
muscle and is covered by the 
trapezius which inserts into the 
spine and thus obscures its out- 
line. The inferior angle is cross- 
ed by the upper edge of the 
lattssimus dor si muscle, from 
which it sometimes receives a 
few fibres. This angle is ren- 
dered prominent when the fore- 
arm is flexed on the arm and 
placed across the back. 

The Humerus . — The 
upper end of the humerus is 
composed of a head joined to 
the tuberosities through the 
medium of the anatomical neck. 
The head projects inwardly from 
the shaft at an angle of 1 20 degrees to it. The lesser tuberosity has inserted into it 
the subscapularis muscle; it presents forward. To its outer side and separating it 
from the greater tuberosity is the bicipital groove for the long tendon of the biceps 
muscle. To the outer side of the groo\'e is the greater tuberosity with its three facets 
for the supraspinatus, infraspinatus, and teres minor micscles. 



Anatomical neck 
Facet for infra- 
spinatus muscle 
Facet for teres 
minor muscle 

Surgical neck 




Facet for supra- 
spinatus muscle 
Bicipital groove 

Greater tuberosity 
Lesser tuberosity 



Fig. 234. — Outer surface of upper end of humerus. 



222 APPLIED ANATOMY. 

The greater tuberosity projects considerably beyond the acromion process and 
therefore forms the most prominent part of the shoulder. Immediately below the 
tuberosities is the surgical neck. It is described as being the portion between the 
tuberosities above and the insertions of the pectoralis major and latissimus dorsi 
muscles below. It is a connnon site for fractures. Half way down the shaft on its 
outer side is the rough deltoid eminence for the insertion of the deltoid muscle. 

Sternoclavicular Joint. — The ligaments uniting the inner end of the clavicle 
to the thorax at the upper end of the sternum are the interclaviciilar, which passes 
from one clavicle to the other across the top of the sternum, the anterior 2Lwdi posterior 
sternoclavicular, and the rhomboid or costoclavicular ligament which passes from the 
clavicle downward and forward to the first rib. This last one limits displacement in 
cases of luxation. There is a fibrocartilaginous disk between the clavicle and sternum, 
forming two distinct joint cavities. The line of the joint slopes downward and outward. 

Acromioclavicular Joint. — The outer end of the clavicle articulates with the 
acromion process by a joint whose surface inclines down and inward, thus favoring 
displacements of the clavicle upward. The ligaments joining them are called the 
superior and inferior acromioclavicular. In reality they are simply the thickened 
portions of the capsular ligament. This capsular ligament is ruptured in the not infre- 
quent cases of luxation which occur here. Running from the under surface of the 
clavicle, a short distance from its outer end, to the coracoid process below, is the 

Anterior sternoclavicular Costoclavicular or rhomboid ligament 

Interclavicular ligament / / Clavicle 

Interarticular fibrocartilage 



Tendon of 
subclavius muscle 



First rib 



First piece of sternum 
Fig. 23s. — Sternoclavicular joint and attachments of the inner end of the clavicle. 

coracoclavicular ligament. It is composed of two parts, an antero-external square 
ligament called the trapezoid, and a postero-internal conical one called the co7ioid. 

The bone may be fractured just external to these ligaments, giving rise to a peculiar 
deformity to which attention will be called in describing the fractures of the clavicle. 

From the coracoid process the coraco-acromial ligament runs outward and up- 
ward to the acromion process, the coracohumeral outward and downward to the neck 
of the humerus, and the costocoracoid ligament inward to the first rib at its cartilage. 

The Shoulder-joint. — The upper extremity being an organ of prehension and 
not of support, the shoulder-joint, which is the articulation which connects it with the 
trunk through the shoulder-girdle, is constructed with the idea in view of favoring 
and permitting motion, and not of supporting weight or resisting force. Hence we 
find it to be a ball-and-socket joint, the one which allows of the freest movements. 

The glenoid cavity is a shallow excavation, not a deep cup, as in the hip. The 
articulating surface of the head of the humerus is extensive but not so large as it 
would have been had the scapula not been made to move on the thorax. The 
clavicle keeps the joint well out from the side of the body; hence the neck of the 
humerus is short. The movements of the arm are so extensive and free that we do 
not have the tuberosities of the humerus so large and set so far away from the artic- 
ular surface as is the case with the femur and its trochanters. 

If the upper portion of the femur was like the upper end of the humerus, the 
lower extremity would be continually rolling in or out, making walking or running 
at least difficult if not impossible. Thus we see that the shape of the bones is 
dependent on the character of their functions.. 




THE SHOULDER-GIRDLE. 



223 



The ligaments of the joints are inelastic tissues; hence those that enter into the 
construction or a movable joint must be loose, and the more movable a joint is, the 
more does its security depend not on its ligaments, but on its muscles. 

The shoulder-joint, like other joints, has a capsular ligament which is attached 
to the adjacent bones and serves to keep the lubricating synovial fluid applied to the 
articulating surfaces. In certain positions this ligament may also ser\'e to a limited 
extent to keep the ends of the bones of the joint in contact. 

Besides this capsular ligament there are fibrous bands which strengthen it at 
certain places as they pass from adjacent processes of bone on one side of the joint 



Superior acromioclavicular ligament 



Tendon of supra 
spinatus muscle 



Acromion process 




Clavicle 



Conoid ligament 
Trapezoid ligament 

Coraco-acromial ligament 
Coracoid process 

Coracohumeral ligament 
Coracobrachialis muscle 
Short head of biceps 



Long head of biceps 



Pectoralis major muscle 



Fig. 236. — Acromioclavicular and shoulder joints. 



to those on the other. The muscles and their tendons pass across the capsule and 
sometimes blend with it, so that there is an intimate relation between the muscles and 
their tendons and the ligaments; finally, there is a third structure called the glenoid 
ligament, which is in reality a fibrocartilage that serves to deepen the glenoid cavity. 
The capsular ligamefit is attached on one side to the edge of the glenoid cavity, 
the anatomical neck of the scapula, and the rim of the glenoid ligament. On the 
other side it is attached above or externally to the anatomical neck of the humerus just 
at the edge of the articulating surface, but on the lower or inner surface it is attached 
some distance below the articular surface (approximately i cm. ) and then turns 
upward toward the edge of the articular cartilage. Thus a fracture through the ana- 
tomical neck might pass outside of the joint above, and inside of it below. The positions 
assumed by the capsule in abduction and adduction are sho'-i^n in Figs. 237 and 238. 



224 



APPLIED ANATOMY. 



Spine 




Acromion process 
Glenoid process 



Capsule 



Joint cavity 



Long head of 
triceps muscle 



Fig. 237. — Section of shoulder- joint, arm adducted, showing the position assumed by the capsule and the points 

of its attachment. 



Acromion process 



Capsule 




Capsule 
Glenoid process 
Long head of triceps muscle 



Fig. 238. — Section of shoulder-joint, arm abducted, showing the attachment of the capsule and the position u 

assumes when the arm is in this position. 



THE SHOULDER-GIRDLE 



225 



The capsular ligament, per se, has not much strength. There are two openings 
in it — one is for the long tendon of the biceps and the other is the opening of the 
bursa beneath the subscapularis muscle. Sometimes there is a synovial extension 
beneath the supraspinatus tendon and rarely, in old people, a communication with 
the subacromial bursa. It is evident that in case of suppuration within the joint the 
pus would tend to find vent first through these openings. 

The laxity of the capsule is such that after the muscles are removed the head 
can be drawn a considerable distance away from the glenoid cavity. When the mus- 

' Acromion process 
Clavicle 



Coracoclavicular ligaments 



Coraco-acromial ligament 




Coracoid process 



Spine 



Glenoid 
ligament 



Long head of biceps 

Glenoid cavity 



Long head of triceps 





Fig. 239. — View of the left scapula and outer end of the clavicle from in front, showing the ligaments pass- 
ing from the coracoid process to the clavicle and acromion process, the glenoid ligament, and attachments of the 
long heads of the biceps and triceps muscles. 

cles are paralyzed the weight of the arm causes the head to fall away and a depres- 
sion is seen beneath the acromion process. The capsule is strengthened by two 
definite and separate ligamentous bands called the coracohumeral and the gleno- 
humeral ligaments. 

The coracohumeral ligament passes from the root of the coracoid process to the 
anterior portion of the greater tuberosity. It is supposed by Sutton to be a regres- 
sion of the tendon of the pectoralis minor muscle. 

The glenoJmmeral liga7nent is a ribbon-like band seen lying alongside of the 

inner edge of the biceps tendon as it passes through the interior of the joint. It 

passes from the root of the coracoid process near the edge of the glenoid cavity to a 

dimple in the lesser tuberosity of the humerus. Sutton considers it a regression of 

15 



226 



APPLIED ANATOMY. 



the tendon of the subclavius muscle and homologous with the ligamentum teres in 
the hip. It is also called the superior glenohumeral ligament, in contradistinction 
to some bands on the lower anterior part of the capsule which are called by some 
anatomists the middle and inferior glenohumeral ligaments. Between the superior 
above and the middle and inferior below is the opening by which the bursa of the 
subscapularis muscle communicates with the joint. 

The glenoid ligament is the wedge- or cup-shaped ring of fibrocartilage which 
deepens the glenoid fossa. It is attached around its edge to the rim of the fossa 
and at its upper end receives the long tendon of the biceps, which divides and blends 
with it on each side. At its lower part when it is attached to the bone it blends with 
the anterior edge of the long tendon of the triceps. 

THE MUSCLES OF THE REGION OF THE SHOULDER. 

The shoulder embraces two sets of muscles: one connects the shoulder-girdle 
with the trunk and the other the humerus with the shoulder-girdle. 

The inner end of the clavicle articulates with the sternum and gives a bony 
support to the shoulder-girdle at this point. The rest of the shoulder-girdle, 



Supraspinatus 
Infraspinatus 



Teres minor 



Outer head 



Long head of triceps 




Levator scapulae 



Rhomboideus 
minor 



Rhomboideus 
major 



^„ _ jHH^B 

of triceps / ,f;i|M/||/|-f ' 



Latissimus dorsi 



Teres major 



Fig. 240. — Scapular muscles. 

comprising the remainder of the clavicle and all of the scapula and bearing the 
weight of the whole upper extremity, hangs from and is supported and moved by 
the muscles which pass from it to the vertebrae posteriorly and to the skull, hyoid 
bone, and ribs anteriorly. 

Anteriorly the clavicle has attached to its upper inner third the clavicular origin 
of the sternomastoid muscle; and on its under surface is the subclavius muscle, which 
arises from the cartilage and anterior end of the fir§t rib. These muscles aid in moving 
the clavicle. Running from the third, fourth, and fifth ribs to the coracoid process is 
the pedoralis minor rmiscle ; and on the side of the chest, passing to the posterior edge 
of the scapula, is the serratus anterior {magnus) muscle. It will be alluded to again. 



THE SHOULDER-GIRDLE. 227 

Posteriorly is the trapezius muscle superficially, and beneath are the omohyoid^ 
levator scapidce, and the two rhomboid muscles. 

The trapezius arises from the superior curved line of the occiput, the liga- 
mentum nuchae, and the spines of the seven cervical and all of the thoracic vertebrae. 
It inserts into the upper surface of the outer third of the clavicle, acromion process, 
and spine of the scapula to near its root. Its upper fibres directly aid in sustaining 
the weight of the upper extremity. It is not infrequently paralyzed, and then falling 
of the shoulder is marked. It also tends to pull the scapula backward toward the 
spine, and rotates it. 

The levator scapulae arises from the transverse processes of the upper four 
cervical vertebrae and passes downward to insert into the posterior edge of the 
scapula between its upper angle and the root of the spine of the scapula. 

The scapula is supported largely by this muscle; hence when the trapezius is 
paralyzed, as occurs in division of its motor nerve, the spinal accessory, this muscle 
is utilized in counteracting its loss. 

The rhomboid muscles arise from the lower part of the ligamentum nuchae 
and the spines of the seventh cervical and upper five thoracic vertebrae and insert 
into the posterior edge of the lower three-fourths of the scapula. 

The serratus anterior (magnus) muscle (Fig. 202), lies beneath the scapula 
and arises from nine slips from the outer surface of the upper eight or nine ribs; 
the second rib receives two slips. It passes backward and upward and inserts into 
the posterior edge of the scapula from its upper to its lower angle. 

The serration attached to the sixth rib is the one that reaches farthest forward 
on the side of the chest. 

The omohyoid muscle arises posteriorly from the upper border of the 
scapula, just behind the suprascapular notch, and then runs upward and forward to 
the under surface of the body of the hyoid bone. It is a digastric or two-bellied 
muscle and its middle tendon is attached by a pulley-like process of the deep cervical 
fascia to the first rib. 

MOVEMENTS OF THE SHOULDER-GIRDLE. 

While the muscles above enumerated comprise all those directly attached to the 
shoulder-girdle and trunk, they are of course assisted to some extent by the muscles 
forming the axillary folds, viz., the pectoralis major anteriorly and the latissimus 
dorsi and teres major posteriorly. 

The shoulder-girdle is elevated by the upper fibres of the trapezius, levator 
scapulae, rhomboidei, sternomastoid (clavicular origin), and omohyoid. It is depressed 
by the lower fibres of the trapezius, latissimus dorsi, lower fibres of the serratus ante- 
rior (magnus), pectoralis major, pectoralis minor, and subclavius. It is drawn forward 
by the pectoralis major, minor, subclavius, serratus anterior, omohyoid, and, if the 
arm is fixed, by the teres major muscles. It is drawn back by the trapezius, rhomboidei, 
and latissimus dorsi muscles. Circumduction is effected by a combined action of 
various parts of these muscles. 

SURFACE ANATOxMY. 

On observing the region of the shoulder it is noticed that it projects well out 

from the trunk, so that the arm hangs free. It has as its framework three bones 

the clavicle and scapula above, forming the shoulder-girdle, and the humerus below. 
They radiate from the region of the joint, the clavicle toward the front, the scapula 
toward the back, and the humerus downward, forming the basis of the shape of the 
shoulder, which is modified by the muscles, fat, and skin. 

The skin and fat bridge over and tend to obliterate the hollows and to a less 
extent obscure the prominences. This is more the case as applied to the muscles 
than the bones, hence the bones form the better landmarks or guides. 

Age and sex modify the surface appearances. In children the bones are but 
slightly developed and their prominences not marked. Fat is usually abundant and it' 
is often no easy task to recognize by the sense of touch the various anatomical parts 
and determine whether or not they have been injured. For this reason one should 



228 



APPLIED ANATOMY. 



endeavor to increase his skill by taking advantage of every opportunity that offers 
for examination. In the case of women the same thing usually exists, but to a less 
degree. In the somewhat emaciated adult male the structures can be recognized to 
best advantage. 

The clavicle is subcutaneous, and even in children and fat people can be felt 
throughout its entire length. Its large, knob-like inner extremity projects consider- 
ably above the upper edge of the sternum, which can be felt at the suprasternal notch. 
Take particular notice of its size and compare it with the one on the opposite side so 
as not to be misled as to its being diseased or luxated. Follow the bone to its outer 
extremity, which is higher than the inner, more so when lying down than when 
standing. A prominent ridge marks its outer extremity; if it is difficult to recognize, 



Infraclavicular triangl 
Outer end of clavicle 



Tip of acromion process 
Greater tuberosity 

Head of humerus 
Deltoid muscle 




Coracoid process 

Lesser tuberosity 
Pectoralis major 



Fig. 241. — Surface anatomy of the shoulder. 

as will often be the case, then continue directly outward to the point of the shoulder, 
which is formed by the tip of the acromion process. Having recognized this point, 
the end of the clavicle will be found about 2.5 to 3 cm. (i to i^in. ) directly inward 
from it. 

In the median line above the sternum is the suprasternal notch with the promi- 
nent sternal origins of the sternomastoid muscles on each side. Just to the outer edge 
of these tendons lie the sternoclavicular joints. The one on the right side marks the 
ending of the innominate artery and the commencement of the right common carotid 
and subclavian. That on the left marks the left carotid with the subclavian directly 
to its outer side and a little posteriorly. 

If the head is extended and turned to the opposite side the clavicular origin of 
the sternomastoid is made visible. It arises from the inner third of the bone. 



THE SHOULDER-GIRDLE, 229 

The inner two-thirds of the clavicle is convex for\vard. Above this portion is 
the subclavian triangle in the supraclavicular fossa. The older third of the clavicle 
is convex backward and from its upper surface the trapezius muscle can be felt pro- 
ceeding upward. This leaves the middle third of the bone free from muscle. 

Under the middle of the bone passes the subclavian artery. It curves upward 
about 2.5 cm. (i in.) above the clavicle to descend again to the sternoclavicular joint. 
The arch so formed indicates the apex of the lung because the subcla\'ian artery- 
rests on the pleura. The internal jugular vein passes down opposite the interval 
between the sternal and clavicular heads of the sternomastoid muscle. 

Just above the clavicle, a little internal to its middle, and behind the clavicular 
origin of the sternomastoid muscle is seen the external jugular vein. It terminates 
in the subclavian vein, which lies to the inner (anterior) side of the artery. To the 
outer side of the artery the cords of the brachial plexus pass upward and inward. 
They become prominent in emaciated subjects when the head is turned forcibly 
toward the opposite side. The posterior belly of the omohyoid muscle varies much 
in its position, sometimes it lies behind the clavicle, at others two or three centimetres 
above it. 

Immediately below the clavicle is the infraclavicular fossa. At its inner extremity 
can be felt the first rib. As it is exceedingly easy to mistake the ribs, it is best, in 
counting them, to locate the second rib by recognizing the angle of the sternum, 
(angle of Ludwig) to which it is opposite, on the surface of the sternum about 5 cm. 
(2 in. ) below its upper edge. Attached to the lower edge of the iiiner half of the 
clavicle is the pectoralis major muscle and to the oiiter third the deltoid muscle. 

This leaves one sixth of the lower edge of the clavicle free from muscular attach- 
ments. This forms the base of the subclavicular triangle and its two sides are formed 
by the adjacent edges of the pectoralis major and deltoid muscles. Beneath this 
triangle runs the first portion of the axillary artery with the vein to its inner side 
and the cords of the brachial plexus to its outer side. Deep pressure at this point 
can compress it against the second rib, but not so effectively as above the clavicle. 

Just to the outer side of the junction of the middle and outer thirds of the 
clavicle, in front of the deepest part of the concavity of the clavicle and about 2.5 cm. 
( I in. ) below it, is the coracoid process. It is better felt by pressing the fingers flat 
on the surface than by digging them in. It is somewhat obscured by the edge of 
the deltoid muscle, which covers it. Running from the coracoid to the acromion 
process is the sharp edge of the coraco-acromial ligament. An incision midway 
between the two processes would open the joint and strike the long biceps tendon 
as it winds over the head of the humerus to reach the upper edge of the glenoid 
cavity. 

Beneath the acromion process is felt the greater tuberosity of the humerus. If 
the arm is placed alongside of the body with the palm facing forward, a distinct groove 
can be felt to the inner side of the acromion process passing downward on a line with 
the middle of the arm. It is the bicipital groove for the long tendon of the biceps 
muscle. The bony process of the humerus to its outer side is the greater tuber- 
osity and that to its inner side, between it and the coracoid process, on a slightly 
lower level, is the lesser tuberosity. It will be noted that the greater tuberosity pro- 
jects beyond the acromion process and forms the prominence of the shoulder. On 
rotating the arm the tuberosities can be distinctly felt moving under the deltoid muscle. 

Following the acromion process around toward the back it turns abruptly where 
it joins the spine of the scapula, forming a distinct angle. This angle is quite prom- 
inent, can be readily seen and felt, and can be used as a landmark for measuring the 
length of the humerus. If the spine of the scapula is followed still farther it ends 
in its root at the posterior border of the bone opposite the upper edge of the fourth 
rib and third thoracic spine. This marks the upper extremity of the fissure of the 
lung; with the arm to the side, the lower angle of the scapula lies over the seventh 
interspace. 

Axilla. — On raising the arm directly out from the body the armpit and axillary 
folds become visible. The rounded edge of the anterior axillary fold is formed by 
the pectoralis major muscle. It follows the fifth rib and its upper end merges with 
the lower edge of the deltoid muscle. 



230 APPLIED ANATOMY. 

If firm pressure is made along the inner or lower edge of the outer extremity 
of the anterior axillary fold the upper end of the biceps muscle can be felt, and lying 
along with it, to its inner side, is the swell formed by the coracobrachialis muscle. 

Along the inner edge of the coracobrachialis muscle lies the axillary artery with 
its vein to the inner side. This is a little anterior to the middle of the axilla. The 
artery can be felt pulsating along the inner edge of the coracobrachialis and can be com- 
pressed by pressure made in an outward and backward direction against the humerus. 
The line of the axillary artery is from the middle of the clavicle down along the inner 
edge of the coracobrachialis muscle, which will be anterior to the middle of the axilla. 

The posterior fold of the axilla is formed by the latissimus dorsi and teres major 
muscles. By deep pressure in the axilla, posterior to the vessels, the arm being 
abducted, the rounded head of the humerus can be felt. 

When the arm is brought more to the side the tissues of the axilla relax and any 
enlarged lymph-nodes present may be recognized. When normal they cannot be felt. 

Winding around the surgical neck of the humerus from behind forward under 
the deltoid muscle about at the junction of its upper and middle thirds is the pos- 



Biceps 
Deltoid 



Pectoralis major 




— Coracobrachialis 

Groove for axillary 
vessels and nerves 



Long head of triceps muscle 

•Teres major and latissimus dorsi muscles 



Fig. 242. — Surface anatomy of the axilla. 

terior circumflex artery and circumflex nerve. Hence a blow at this point may injure 
the nerve and cause paralysis of the deltoid muscle. The line of fracture of the 
surgical neck of the humerus would also lie at this point. 

DISLOCATIONS OF THE CLAVICLE. 

Dislocation of the Sternal End of the Clavicle. — The sternal end of the 
clavicle is most commonly dislocated forward. Other dislocations, which may be 
upward or backward, are very rare. The range of movement of the clavicle approxi- 
mates 60 degrees. 

The bone is lowest when the elbow is brought forward across the front of the body 
and highest when the arm is raised and placed behind the neck. The luxation is pro- 
duced by the shoulder being violently depressed and pushed backward, as in falling 
on it; in some cases an inward thrust may be added. As the clavicle descends its under 
surface comes into contact with the first rib, which acts as a fulcrum, and the inner 
extremity is lifted upward and forward, rupturing the sternoclavicular ligaments. The 
rhomboid ligament remaining intact prevents a wider displacement of the bone. 



THE SHOULDER-GIRDLE. 



231 



As regards treatment, to reduce the luxation the shoulder should be elevated 
and drawn outward and backward. While pressure is made on the protruding bone 
the arm is used as a lever and the bone tilted into place. Usually reduction can be 
readily accomplished, but most people have found it difficult to retain the parts in 




Sternum 



Clavicle 



Subclavius muScle 



Costoclavicular or 
rhomboid ligament 



First rib 

Second rib , 

Fig. 243. — Dislocation of the sternal end of the clavicle upward and forward, showing how the first rib acts as a 

fulcrum and the clavicle as a lever. 

place. The only sure way of doing so is to keep the patient in bed on his back. 
Stimson, following Velpeau and Malgaigne, advises the application of an anterior 
figure eight bandage of plaster of Paris; Hamilton says deformity remains after any 
method of treatment, but that function 
will be but little impaired. 

In upward dislocations the case of 
R. W. Smith has shown that the end of 
the bone passes behind the sternal origin 
of the sternomastoid muscle. 

In backward dislocations pressure 
on the trachea and oesophagus have 
caused difficulty in breathing and swal- 
lowing; cyanosis due to pressure on the 
internal jugular vein has been observed 
in one case. When one recalls the 
function of the clavicle in keeping the 
shoulder out from the body, it is readily 
seen that when the security of its inner 
attachment has once been destroyed dis- 
placement is favored by the weight of 
the upper extremity as well as by the 
action of all the muscles which pass 
from the head, neck, and trunk to the 
shoulder-girdle and humerus. 

In these dislocations of the sternal 
end of the clavicle the fibrocartilaginous 
disk of the joint sometimes is carried out with the clavicle and sometimes remains 
attached to the sternum, more often it follows the clavicle. 

Dislocation of the Acromial End of the Clavicle. - 
the clavicle may be dislocated either upward or downward, 
tions are upward. 

The displacement is usually produced by direct violence 
back of the shoulder driving the acromion down and inward. 




Fig. 244. — Luxation of the outer end of the clavicle 
upward, showing the coracoid process acting as a fulcrum. 
As the outer end of the clavicle rises, the lower angle of the 
scapula is carried toward the median line and the acromion 
process is depressed and torn loose from the clavicle above. 



—The acromial end of 
Nearly all the disloca- 



a blow on the top or 
The clavicle not only 



232 APPLIED ANATOMY. 

rises but also goes backward, or the scapula comes forward, so that the end of the 
clavicle may rest on the acromion process. In this dislocation the base of the cora- 
coid process, on which the clavicle rests and to which it is bound by the conoid and 
trapezoid ligaments, acts as a fulcrum. The scapula rotates on an anteroposterior 
axis, passing through the base of the coracoid process, and as the inner portion of 
the bone rises, its outer portion, — that is, the acromion process, — descends and is torn 
from the outer end of the clavicle. 

The deformity produced by the upwardly projecting end of the clavicle is typical. 
The luxation may be complete or incomplete. When incomplete the injury is con- 
fined to the acromioclavicular joint; when complete the conoid and trapezoid ligaments 
are partially or wholly ruptured. 

The joint usually possesses a poorly developed fibrocartilage and inclines upward 
and outward so that the inclination favors the rise of the clavicle. When the conoid 
and trapezoid ligaments are not ruptured they serve as the axis on which the scapula 
rotates forward so that the outer end of the clavicle slips backward on the acromion 
process. This led Hamilton to describe these luxations as backward luxations. In 
rare instances the end of the clavicle seems to be displaced posteriorly without 
rising above its normal level. We reported one such case in the Annals of 
Surgery several years ago. Reduction of the displacement is easily effected, but 
the same difficulty in keeping the bone in place has been experienced in this disloca- 
tion as in dislocations of the inner extremity. Bandages going over the shoulder 
and down the arm and under the elbow are commonly employed. The only sure 
way of keeping the clavicle in its proper position is to operate and fasten it to the 
acromion with wire or chromicised catgut. When the patient is put in bed the bones 
are readily replaced. 

Downzvard dislocation though rare does seem to have sometimes occurred. 
From the fact of the under surface of the clavicle resting almost or quite on the 
coracoid process it is difficult to see how it is possible for this injury to take place. 
It must take place while the scapula is violently twisted on the clavicle. The 
displacement is readily reduced and shows but little tendency to recurrence. 

DISLOCATIONS OF THE SHOULDER. 

The dislocations of the shoulder are to be studied from the anatomical and not 
from the clinical standpoint. A knowledge of the anatomical construction of the 
various parts involved is to be applied to the explanation and elucidation of the 
methods of production, the signs and symptoms observed, and the procedures neces- 
sary for reduction. 

Classification. — For our purpose there are two forms of dislocations of the 
shoulder — anterior and posterior. These two forms are entirely different and must 
be studied separately. 

Anterior Dislocation. — An anterior luxation is one in which the head of the 
humerus is either on or anterior to the long head of the triceps muscle at the lower 
edge of the glenoid cavity. 

Posterior Dislocation. — A posterior luxation is one in which the head goes poste- 
rior to the glenoid cavity and usually rests beneath the spinous process of the scapula, 
hence this is called subspinous dislocation. 

When the head is luxated anteriorly it may pass so far inward as to rest between 
the coracoid process and the clavicle; hence this form is called subclavicular. 

When the head does not pass so far inward, but rests on the anterior edge of the 
glenoid cavity below the coracoid process, it is called a subcoracoid luxation. 

When it rests on the anterior and lower edge of the glenoid cavity, sometimes 
on the long head of the triceps muscle or just anterior to it, it is called a subglenoid 
luxation. 

ANTERIOR DISLOCATION OF THE SHOULDER. 

The head of the bone almost always comes out through the anterior portion of 
the capsule and slips beneath the coracoid process. From this point it may shift its 
position either a little farther inward, when it is called a subclavicular luxation, or a 
little farther downward and outward, when it receives the name of subglenoid. 



THE SHOULDER-GIRDLE. 



233 



As a matter of fact the head usually comes to rest beneath the coracoid process 
and permanent fixation of the bone either in the subclavicular or subglenoid positions 
is very rare. As the symptoms and methods of treatment are identical they will all 
be included under the one head of subcoracoid luxations. What are commonly 
regarded as subglenoid luxations are really subcoracoid. 

Method of Production of Anterior Luxations. — Anterior luxations are produced 
by the arm being hyperabducted, rotated outward, and the head of the bone pushed 
or pulled in toward the body. Rotation may not be essential, but it is largely 
responsible for the wide detachment of the capsule which is present in these injuries. 
When the arm is raised from the body much beyond a right angle the greater 
tuberosity strikes the acromion process. If the hyperabduction is continued the acro- 
mion process acts as a fulcrum and the head of the bone is lifted from its socket, 
tearing away the capsule of the joint in front of and below the glenoid cavity. 




Fig. 245. — Dislocation of the shoulder; action of the bones; by extreme abduction of the humerus over the 
acromion process as a fulcrum the head is levered out of the socket. 



If now the arm rotates, the capsule is still farther detached and if the force con- 
tinues to act, as in those cases in which a person is thrown forward and alights on 
the outstretched arm, or if the axillary muscles contract, the head is thrust from its 
socket. After once leaving the socket, subsequent movements may cause the head 
to assume various positions around the glenoid cavity; as a matter of fact it is almost 
always below the coracoid process. 

Parts Injured. — When the luxation occurs the arm is hyperabducted and, owing 
to the acromion process being somewhat posterior to the glenoid cavity, pointing 
backward, this places it up almost or quite alongside of the head. The force which 
thrusts the bone out acts downward toward the axilla and inward toward the body. 
The posterior border of the scapula is prevented from descending by the levator 
scapuke and rhomboid muscles, hence it is the joint which descends and tears loose 
the capsule already stretched tightly over the head of the humerus. 

This is the reason why the lower portion of the capsule is torn; it is the longi- 



234 



APPLIED ANATOMY. 



tudinally acting force that does it. When the transverse force acts it is expended on the 
anterior portion of the joint because the joint is at the anterior portion of the scapula. 
Posterior to the joint the scapula rests on the chest, so it is its anterior portion which 
is forced inward, thus rupturing the capsule at this point. The fulcrum, or acromion 
process, is also posterior to the midline of the joint. 

By a combination of these two forces (longitudinal and transverse) the capsule 
is ruptured at its lower and especially its anterior portion. Its tearing is favored by 
a twisting or external rotation of the humerus. The attachment of the capsule is 
torn from the rim of the glenoid cavity, not from the humerus, and a fragment of the 
bony rim frequently comes with it. The opening is large and embraces nearly or 



Prominent acromion 
process 



Coracoid procesi 



Tense fibres of 
the deltoid 

Prominence formed 

by the head of 

the humerus 




Fig. 246. — Surface view: subcoracoid dislocation of the humerus, showing the elevation of the shoulder, 
abduction of the arm, prominence of the displaced head below the coracoid process, flattening of the shoulder, 
and tense fibres of the deltoid muscle. 

quite half the circumference of the joint. It is limited above by the coracoid process. 
The coracohumeral and superior glenohumeral ligaments lying in front of the long 
tendon of the biceps also limit the tear upwards. If the tear does not extend so high 
it is because the subscapularis muscle, instead of being torn, is wedged in between 
the head and the coracoid process. Below, the tear is limited by the insertion of the 
long head of the triceps. As the head luxates it cannot pierce the triceps tendon, 
so it slips behind it in a posterior luxation and in front of it in an anterior luxation. 
The supraspinatus, infraspinatus, and teres minor muscles are all posterior; they 
blend more or less with the capsule and as the head luxates they are stretched with 
it over the glenoid cavity. 

The long tendon of the biceps, while it may sometimes be torn loose from the 
bicipital groove after rupture of the transverse ligament, is usually so loose that it 



THE SHOULDER-GIRDLE. 



235 



follows the head without being detached from its connections. The subscapularis 
muscle not infrequently has its lower edge torn. 

The brachial plexus and blood-vessels are pushed inward by the head, but when 
the arm is abducted they are stretched over it, running close to the coracoid process. 




Fig. 247. — Subcoracoid dislocation of the humerus, showing the position of the bones in relation to each other and 

to the soft parts. 

As the circumflex nerve winds around the surgical neck of the humerus, it may be 
ruptured or tightly stretched over the head of the bone. 

Hyperabduction stretches the vessels and nerves so forcibly over the head just 
prior to its leaving the socket as sometimes to produce serious injury to them. 



Signs and Symptoms. 

There is (i) at first elevation then lowering of the shoulder, (2) flattening of the 
deltoid muscle, (3) projection of the elbow away from the side. (4) The normal 
hollow below the outer third of the clavicle is filled up ; the head, covered by the deltoid, 
may sometimes even make a rounded prominence at this point which can frequently be 
felt. (5) If the elbow is raised and the hand placed on the opposite shoulder and held 
there the elbow cannot be brought flat on the chest (Dugas's sign), (6) with the 



236 APPLIED ANATOMY. 

arm to the side the distance from the acromion process to the external condyle is 
increased, with the arm abducted to a right-angle, the same distance is decreased as 
compared with the previous position as well as when compared with the arm of the 
opposite side (see Fig. 248). 

1. Lowering the shoulder obviates pain by relaxing the deltoid and preventing 
it from forcing the head upward in its displaced position. 

2. Flattening of the shoulder is due to the head and tuberosities being displaced 
inward, thus leaving the socket empty. A marked depression can be felt with the 
fingers below the prominent acromion process. 

3. Projection of the elbow from the side is due to tension of the deltoid muscle 
because the head is lower than normal. In its natural position the top of the head is 
about level with the coracoid process; when luxated it is below it. 

4. The normal hollow below the outer third of the clavicle is lost because here i.s 
where the head lies. It may form a distinct prominence and when the arm is rotated 




Fig. 248. — Subcoracoid dislocation of the shoulder. The head of the humerus has slipped off its pedestal or 
shoulder-girdle onto the side of the thorax. This shows how the arm is shortened and why it is necessary to- 
make traction in order to replace the humerus up again on the shoulder-girdle. 

if the surgeon lays his hand at this point the tuberosities can be felt to rotate beneath. 
If the arm is abducted the head can usually be felt in the axilla, where it may even 
form a prominence. 

5. In Dugas's test the elbow cannot be brought to the chest because the outer 
end of the humerus is held close to the chest-wall. On account of the thorax being 
rounded like a barrel it is necessary for the outer end of the bone to rise as the inner 
end falls. 

6. The reason for the difference in measurements when the shoulder is luxated 
is readily seen by the fact that the head is displaced downward and inward as shown 
in the accompanying figure. 

Treatment. 

Reduction of an anterior luxation of the shoulder can be accomplished in two 
ways, viz. , the direct, in which the head is pulled or pushed back into the socket, 
and the indirect, in which it is levered back. 

Direct Method. — This consists in first placing the arm in approximately the 
position it occupied when luxated (abduction) and then pulling or pushing the 
head toward and into the socket while the arm is rotated to relax the capsule and 
allow the head to enter. The usual obstacle to reduction of a recent luxation is 
muscular contraction. The main muscles acting are the deltoid, pectoralis major, 
latissimus dorsi, and teres major. To effect reduction the action of these muscles 
must either be held in abeyance or overcome by force. This may be accomplished 
in several ways, viz. , by the use of general anaesthesia, by such gentle manipulations 



THE SHOULDER-GIRDLE. 



237 



as will not incite the muscles to contraction, by a quick movement accomplishing the 
object before the muscles are able to contract, or, finally, by overcoming the muscular 
action bv steady continuous traction. General anaesthesia is the surest way of obvi- 
ating muscular contraction. 

The question of muscular contraction having been solved by one or more of these 
expedients the actual replacement is to be accomplished by dragging or pushing the 
head back over the route it took in coming out. The opening in the capsule is 
below and anterior, therefore the arm is to be strongly abducted, and traction made 
upward and backward. This drags the head upward and backward over the rim of 
the glenoid cavity into its socket. If it does not enter readily it is because of tension 



Coracoid process 



Acromion process 

Long head of biceps 
Supraspinatus 

Infraspinatus 
Teres minor 



Deltoid detached 
from the clavicle 
and turned back 

Long head 
of triceps 



Coracobrachialis 

and short head 

of biceps 



Pectoralis major 



Pectoralis minor 



Displaced head 
of humerus 




Subscapularis 



Fig. 249. — Subcoracoid dislocation of the shoulder. Dissection showing the relation of the muscles to the dis- 
placed humerus. 

of the untorn part of the capsule; this is to be remedied by gently rotating the arm, 
when the proper position will be revealed by the slipping of the head into place. Rota- 
tion in either direction beyond the proper point narrows the tear in the capsule and 
keeps the head from entering. Traction is necessary in order to replace the head of 
the humerus on its pedestal or shoulder-girdle from which it has fallen onto the side 
of the chest (see Figs. 248 and 250). 

If it is desired to tire the muscles out, the plan of Stimson is best. Place the 
patient in a canvas hammock and allow the arm to hang downward through a hole 
in the canvas. Fasten a ten-pound weight to the wrist and inside of six minutes the 



238 



APPLIED ANATOMY. 



weight will have dragged the head of the humerus into place. This same object can 
be carried out, but not so well, by having the patient lie on the floor and pulling the 
arm directly upward by means of a rope and pulley. Here the weight of the body 
acts as the counter force. 

Other means, such as the heel in the axilla, etc., may be found described in 
works on surgery, but it is to be remembered that the objects to be sought are (i) to 
overcome the action of the deltoid by abducting the arm, (2) to overcome the axillary 
muscles — pectoralis major, latissimus dorsi, and teres major — by traction, and (3) to 
loosen the capsule and open the tear to its widest extent by rotation while the head 
is pushed with the hand toward and over the lower and anterior edge of the socket. 




Fig. 250. — Diagram to show how rotation influences the size of the rent in the capsule. The square rep- 
resents the rent in the capsule and the circle the head of the humerus. If the humerus is rotated too much in 
the direction of the arrows, either to the right or left, the opening in the capsule is so narrowed as to obstruct 
the passage of the head. 

Indirect Method. — The indirect or lever method has been best systematized 
by Kocher of Berne, although Henry H. Smith, a former professor of surgery in the 
University of Pennsylvania, taught a similar method previously (see H. H. Smith's 
"Surgery," 11 vols., also Packard's " Minor Surgery," p. 204, and Ashhurst's "Sur- 
gery," 2d Ed., Phila. 1878, p. 284). Kocher's method is as follows: First Step. 
— Flex the forearm until it forms a right angle with the arm, then, with the elbow 
touching the side of the body, rotate the arm outward 90 degrees until the forearm 
points directly outward (Fig. 251). This causes the head of the bone to rotate out- 
ward and leave the side of the chest to take a position close to the glenoid cavity. 
Second Step. — The arm being held in this position, the elbow is raised forward until 










Fig. 251. — Kocher's method of reducing dislocation of the shoulder: First step — Flex the forearm at a right 
angle to the arm; bring the humerus alongside the chest, the elbow nearly touching the side, and rotate outward 
as far as the arm will go without undue force. 

it forms a right angle or a little more with the long axis of the body. This relaxes 
the coracobrachialis muscle, releases the lesser tuberosity, which may be caught against 
it, and allows the head to pass outward and ascend from its low position up into the 
glenoid cavity (Fig. 252). Third Step. — Carry the arm obliquely inward, place 
the hand on the opposite shoulder and bring the elbow down to the surface of the 
chest, the humerus pointing diagonally downward and inward as in the Velpeau 
position for fractured clavicle (Fig. 253). 

The mechanism, as readily demonstrated on the cadaver, is as follows: The 
head lies to the inner side of the glenoid cavity with the tense posterior portion of 
the capsule passing backward. When external rotation is made the capsule is wound 
around the head and upper portion of the neck and the head moves out. In some 
instances the head will not only move out but will likewise move up and be drawn at 



THE SHOULDER-GIRDLE^ 



239 



once into place. Bringing the arm forward and upward relaxes the coracobrachialis 
muscle, while bringing it across the chest in the last step assists the head over the 
rim of the glenoid ca\ity and restores the member to its normal position. Prof. 
H. H. Smith brought the elbow forward before making the external rotation instead 
of after, as did Kocher. This is probably the better way because persistence in rotat- 
ing outward when the lesser tuberosity is caught beneath the tense coracobrachialis 
muscle is one cause of the frequent fracture of the humerus in attempting to carry 




Fig. 252. — Kocher's method of reducing dislocation of the shoulder: Second step — Keeping the arm in external 
rotation, raise the elbow until the humerus reaches the vertical line or a little beyond. 

out Kocher's method ; another cause is the fixation due to strong muscular con- 
traction or to jamming of the head between the scapula and side of the chest. 

This method can be used without anaesthesia, but it is at times exceedingly pain- 
ful and savors of cruelty. It is particularly applicable for old and severe cases. It 
depends for its efficiency on the integrity of the posterior portion of the capsule, if this 
has been torn loose the method fails and the head simply rotates in situ. If this 
latter is the case, reduction can readily be effected by direct traction and manipulation. 




Fig. 253. — Kocher's method of reducing dislocation of the shoulder: Third (final) step — Rotate the arm inward 
and place the hand on the opposite shoulder bringing the elbow down on the anterior surface of the chest. 



POSTERIOR DISLOCATIONS OF THE SHOULDER. 

Posterior dislocations are always beneath some portion of the spine of the scapula, 
hence they have been called snbspiyioics. When the head lies anteriorly under the 
posterior portion of the acromion process they have been called subacromial. 

Posterior luxations are rare. They occur either when the arm is abducted with 
strong internal rotation or by direct violence, such as a blow on the anterior portion of 
the shoulder, which forces the head out of its socket backward. The posterior portion 
of the capsule is torn and the head lies posterior to the glenoid cavitv with its anatomi- 
cal neck res.ting on the rim and the lesser tuberosity in the glenoid fossa. The arm 
is inverted and abduction and rotation impaired. The capsule is ruptured by internal 
rotation while the arm is in a position of abduction, and then a push sends the head pos- 
teriorly. We have seen it as a congenital affection resulting from injury in childbirth. 



240 



APPLIED ANATOMY. 




Lesser tuberosity of the humerus 
Relaxed tendon of coracobrachialis 
and short head of biceps 



Fig. 254. — Raising the arm to a vertical line or a little more relaxes the tendon of the coracobrachialis 
and short head of the biceps muscle and allows the lesser tuberosity of the humerus to pass beneath it when the 
arm is rotated inward to place the hand on the opposite shoulder. 




Prominence formed by 
the head of the humerus' 



\ 




Fig. 255. — Posterior luxation of the shoulder. The head of the humerus makes a prominence beneath tne 
spine of the scapula and the arm is rotated inward. (From a photograph of author's patient by Dr. A. P. C. 
Ashhurst.) 



THE SHOULDER-GIRDLE. 241 

The infraspinatus, teres minor, and sometimes the subscapularis muscles are 
ruptured and frequently there are accompanying fractures of the tuberosities or some 
part of the scapula. The head makes a prominence posteriorly and the arm hangs to 
the side and in a position of inward rotation. Reduction, if the injury is recent, is 
likely to be easily effected by pushing the head directly forward into its socket. 

FRACTURES OF THE SHOULDER-GIRDLE AND UPPER END 

OF THE HUMERUS. 

FRACTURES OF THE CLAVICLE. 

Fractures of the clavicle divide with those of the radius the distinction of being 
the most frequent of any in the body. 

The clavicle is most often broken in its middle third, next in its outer, and, lastly, 
in its inner third. 

Fracture of the Inner Third of the Clavicle. — This is the rarest frac- 
ture of the clavicle and has its main anatomical interest in relation to the costoclavic- 
ular ligament. This ligament runs obliquely upward and outward from the upper 
surface of the cartilage of the first rib to the lower surface of the clavicle, a distance 
of 2 cm. (4 in.). 

Immediately in front of the outer portion of this ligament is the insertion of the 
tendon of the subclavius muscle. The line of the fracture may be either transverse 
or oblique ; if oblique it follows the same direction as do the fractures of the middle 
third of the bone, viz. , from above, downward and inward. The displacement of 
the inner fragment is upward and of the outer fragment downward. The displace- 




FiG. 256. — Fracture of the clavicle just outside of the middle, with the customary deformity. 

ment of the inner fragment upward is promoted by the attachment of the clavicular 
origin of the sternomastoid muscle: it is opposed by the costoclavicular (rhomboid) 
ligament and to a less extent by the subclavius muscle. 

Fracture of the Middle Third of the Clavicle. — The clavicle is most 
frequently broken in the outer half of its middle third. The bone at this part is most 
slender; it is here that the anterior curve passes into the posterior; and, finally, it has 
fewer muscular attachments at this situation. The upper surface has arising from its 
inner third the clavicular origin of the sternomastoid muscle. Its middle third has 
no muscular attachments, and on its outer third is the trapezius muscle. On the 
lower or anterior surface on its inner half is the clavicular origin of the pectoralis 
major and on its outer third is the deltoid. This leaves the outer half of the middle 
third free from muscular attachments, with the exception of the subclavius on its 
under surface. It is through this part of the bone that fractures occur. 

Sometimes in children the line of fracture is transverse, but most often it is 
oblique and always in the direction from above downward and inward. 

The displacement of the inner fragment is upward, and of the outer fragment 
downward and inward. This produces the deformity seen in Fig. 256. The inner 
fragment is pulled up by the clavicular origin of the sternomastoid muscle. The 
support of the clavicle being gone, the shoulder falls down and in. It is impelled in 
that direction, first, by the weight of the upper extremity, and, secondly, by the action 
of the axillary fold muscles, — pectoralis major and minor anteriorly and teres major 
and latissimus dorsi posteriorly, and by the subclavius to some extent. The anterior 
edge of the scapula rotates inward and its posterior edge tilts outward. 

In this manner overlapping is produced, and measurements of the injured and 
healthy sides taken from the sternoclavicular to the acromioclavicular joint will 
show some shortening on the injured side. As the continuity of the shoulder-girdle 
16 



242 



APPLIED ANATOMY. 



has been destroyed and its prop-like action lost, its function of abduction ceases, and 
the patient is unable properly to elevate the arm. Sometimes the brachial plexus or 
subclavian vessels are injured i)y the inner end of the outer fragment. The artery 
passes beneath the middle of the bone, the vein being to its inner side and the 



Trapezius 
Coracoid process 



Deltoi 




Clavicular fibres 
of sternomastoid 

— Brachial plexus 

Suliclavian vessels 



Pectoralis minor 



Pectoralis major 



Fig. 257. — Fracture of the clavicle just outside the middle. The outer fragment is displaced downward and 
inward and the inner fragment upward. The brachial plexus and subclavian vessels are behind the inner end of 
the outer fragment. 

brachial plexus to its outer side. We have operated on one such case of injury to 
the brachial plexus; and cases of haematoma arising from injury to the veins and 
aneurism from injury to the artery have been recorded. 

Treatmeyit. — When the line of fracture is oblique and in an adult, healing with a 
certain, often considerable, amount of deformity is almost constant, the only efficient 




Fig. 258. — Showing how the shoulder falls inward and the posterior edge of the scapula tilts outward when the 
prop-like action of the clavicle is destroyed by fracture. 

way of combating its occurrence is to place the patient in bed on his back. This is the 
best way of removing the weight of the arm, of quieting the muscles, and by pressure 
of the scapula close to the thorax of levering the shoulder out (see Fig. 258). 



THE SHOULDER-GIRDLE. 



243 



Fracture of the Outer Third of the Clavicle. — Attached to the outer third 
of the clavicle on its under surface, extending not quite to its end, are the coraco- 
clavicular (conoid and trapezoid) ligaments. The conoid inserts into the conoid 
tubercle near the posterior edge of the clavicle, while the trapezoid is broader and 
passes from the conoid tubercle outward and anteriorly not quite to the extremity 
of the bone (see Fig. 267). The bone may be fractured either through the part to 
which the conoid and trapezoid ligaments are attached, or between them and the end 
of the bone, a distance of about 2 cm. (i in.). The line of the fracture is either 
transverse or inclines backward and outward (see Fig. 259). 

The displacement of the outer fragment is downward and inward. If the fracture 
is through the ligaments the displacement is not marked. If beyond the ligaments, 
the shoulder drops, carrying down the outer fragment, and the inner fragment may 
be elevated slightly above the outer one, but the up-and-down displacement is not 



Pectoralis minor 




Pectoralis major 



Latissimus dorsi 



Teres major 

Fig. 259. — Fracture of the outer end of the clavicle. The outer fragment is drawn inward by the pectoralis major 

latissimus dorsi, and teres major muscles. 

conspicuous. In many cases the anteroposterior displacement is very marked and 
peculiar. The outer fragment is bent sharply inward at the site of fracture, producing 
a deformity which is pathognomonic. It is caused by the curved shape of the bone at 
this point, by the weight of the arm, and by the action of the muscles passing from 
the shoulder to the trunk, especially the pectoralis major (see Fig. 259). 

Treatment. — As the deformity is not very marked any of the usual bandages, 
such as those of Velpeau, Desault, or posterior figure eight are fairly satisfactory. 



FRACTURES OF THE SCAPULA. 

While fractures of the scapula are not common, there are a few anatomical facts 
in reference to the scapula and its muscles which are worth calling attention to. 

The scapula is liable to be fractured more or less transversely through the body 
below the spine; the acromion and coracoid processes have been broken; it has also 
been fractured through the surgical neck, and the glenoid process has been chipped off. 



244 APPLIED ANATOMY. 

Fracture Through the Body. — The scapula has attached to its under surface 
the subscapularis muscle, along its posterior border is the serratus anterior (magnus) 
and rhomboids, to its dorsum and edge below the spine are attached the infraspina- 
tus, teres minor, and teres major muscles. These are covered by a strong, tough 
fascia which dips between them to be attached to the bone. 

Bearing these facts in mind it is readily appreciated why in many of these 
fractures, which usually traverse the bone below its spine from the axillary to the 
vertebral border, the displacement is slight, and why healing occurs with some 
appreciable deformity but with little disability. 

If, however, the fracture is low down, breaking off the lower angle, then the teres 
major and lower portion of the serratus anterior (magnus) muscles displace the frag- 
ment toward the axilla, and this is to be borne in mind in treating the injury. 

Fracture of the acromion process is more rare than would be expected. 
It is the result of direct violence, and the displacement and disability resulting from 
the injury are slight. The acromion is covered by a dense fibrous expansion from 
the trapezius above and the deltoid below, and these prevent a wide separation of 
the fragments. 

Fracture of the coracoid process is also rare and may occur from muscular 
contraction or direct violence, as in luxation of the shoulder. It might be thought 
that owing to the action of the pectoralis minor, coracobrachialis, and short head of 
the biceps muscles, which are attached to it, it would be widely displaced, but this 
is not so, for the conoid and trapezoid ligaments still hold it in place. 

Fractures through the surgical neck are not common. They pass down 
through the suprascapular notch and across the glenoid process or head, in front of the 
base of the spine and behind and parallel with the glenoid fossa. The tendency of 
the outer fragment to be dragged down by the weight of the arm is resisted by the 
coraco-acromial and coracoclavicular (conoid and trapezoid) ligaments as well as by 
the inferior transverse ligament, which runs from one fragment to the other from 
the base of the spine, on the posterior surface, to the edge of the glenoid cavity. 
These ligaments all remain intact. 

Fracture through the glenoid process, chipping off a greater or less por- 
tion of the articular surface, is rarely diagnosed. It occurs sometimes in cases of 
luxation. The long head of the triceps muscle may be fastened to the detached frag- 
ment and is liable to pull it downward and therefore some interference with the func- 
tions of the joint would be apt to remain and prevent complete recovery. 

FRACTURES OF THE UPPER END OF THE HUMERUS. 

Fractures of the upper end of the humerus may occur through the anatomical 
neck, through the tuberosities, detaching one or both, and through the surgical neck 
just below the tuberosities. These fractures are frequently associated with luxation 
of the head of the bone. 

Fracture through the Anatomical Neck. — This occurs as the result of direct 
violence and most often, though not always, in old people. The line of fracture does 
not always follow exactly the line of the anatomical neck, but may embrace a portion 
of the tuberosities. The fracture may or may not be an entirely intracapsular one. 
The capsule in its upper or outer portion is thickened at its humeral end by more or 
less blending with the tendons of the muscles which pass over it. The capsule at this 
point is attached to the anatomical neck almost or quite up to the articular surface. 
On the under side to the contrary it passes about a centimetre below the articular 
surface and doubles back to be attached somewhat closer to it (see Fig. 266, page 253). 

In consequence of this arrangement, a fracture which follows the anatomical neck 
would be within the joint below and just outside of it above. As a matter of fact, 
some of these fractures are intra- and some partly extracapsular. This influences the 
amount and character of the displacement and the course of healing. If the fracture 
is entirely intracapsular, bony union may not occur, as no callus may be thrown out 
by the upper fragment and atrophy of the fragment may ensue. The fragment is 
apt to be much displaced, being tilted and lying to the inner side anteriorly. 
Sometimes it is entirely extruded from the joint. In one case we have seen it lodged 
in front under the anterior axillary fold. 




'i't 



« f 



THE SHOULDER-GIRDLE. 245 

The signs and symptoms will vary much, according to the position of the head, 
and a positive diagnosis may be impossible. A thorough knowledge of the surface 
anatomy is essential in these cases and a careful comparison should be made with the 
opposite healthy shoulder. Impaction sometimes occurs, and is said to be most 
often of the upper fragment into the lower, sometimes splitting it and detaching to a 
certain extent one of the tuberosities. Sometimes it is the lower fragment which is 
impacted into the upper. 

Fractures through the Tuberosities. — Like the former these are often 
accompanied by luxation, especially if one or both of the tuberosities is detached. 
These fractures are frequently blended with fracture through the anatomical neck. In 
this fracture, however, the influence of the muscles is to be remembered. The supra- 
spinatus, infraspinatus, and teres minor insert into the greater tuberosity, and the sub- 
scapularis into the lesser. The line of fracture may pass 
through their insertions and the displacement may be slight. 
The upper fragment is, however, liable to be tilted out- 
ward by the contraction of the supraspinatus muscle, which 
is attached to the upper portion of the upper fragment, while 
there is no muscle attached below to counteract it. In this 
case the shaft of the humerus is drawn up and out by the 
deltoid and is felt beneath the acromion process. There is 
but little rotatory displacement of the upper fragment because 
the subscapularis anteriorly is neutralized by the infraspinatus 
and teres minor posteriorly. 

In those instances in which there is not much displace- \ 

ment of the upper fragment, the lower one may be drawn 
inward and forward by the action of the muscles of the ax- 
illary folds. 

Fractures detaching the tuberosities are almost always 
accompanied by luxation. If the greater tuberosity alone is 
detached, it is drawn up beneath the acromion by the supra- 
spinatus. 

In all these fractures the subsequent disability is often Fig. 260.— Fracture through 
great and the prognosis is unfavorable. They are amongst ^eruf ^"""'"^^ """'' °^ ""' ^"^ 
the hardest in the body to correctly diagnose. They are 

treated sometimes with a shoulder-cap and sometimes with the arm in the abducted . 
position while the patient is kept in bed. Epiphyseal separation will be alluded to 
farther on. 

Fractures of the Surgical Neck. — These are the- most common fractures 
of the humerus. The surgical neck of the humerus is usually defined as the portion 
between the lower part of the tuberosities and the upper edge of the tendons of the 
pectoralis major and latissimus dorsi muscles. Often, however, the tendons of these 
two muscles continue almost or quite up to the tuberosities, hence there is little or 
no interval here and the line of fracture then passes through the upper part of these 
tendons. 

The fractures occur both from direct and indirect violence and the direction of 
the force has probably something to do with the displacement of the fragments. 

Displace7nent. — It can readily be seen that if a blow is received on the humerus 
below the tuberosities while the arm is in a somewhat abducted position the head will 
be supported by the glenoid process (head) of the scapula and the bone will be 
fractured through the surgical neck and driven in towards the body, and, as the 
scapula is supported posteriorly, the movable lower fragment is displaced anteriorly. 
After the fracture has occurred, and possibly in some cases aided by the peculiar 
direction of the fracturing force, the lower fragment is drawn upward by the muscles 
running from one side of the fracture to the other. These are the deltoid, biceps, 
coracobrachialis, and the long head of the triceps. The typical displacement is 
for the upper fragment to be abducted and some say rotated out — this latter is not 
without doubt. The lower fragment is certainly in front and to the inside of its 
normal position. 

The abduction of the upper fragment is due to the unresisted action of the supra- 
spinatus muscle. The subscapularis in front and the teres minor and infraspinatus 



246 



APPLIED ANATOMY. 



behind nearly or quite balance each other, thus causing little or no lateral displace- 
ment. The displacement inward and anteriorly of the lower fragment, is due to the 
action of the violence as already detailed and is aided by the action of the pectoralis 
major, the teres major, and latissimus dorsi muscles, all of which pass from the lower 
fragment just below the seat of fracture inward to the trunk. 

The longitudinal displacement is peculiar. As the lower fragment is drawn up 
its upper end may be felt through the deltoid muscle below and toward the inner side 
of the acromion. While the displacement in most cases is not marked, in some the 
lower fragment can readily be felt in the axilla (Fig. 261). 

Sometimes instead of the lower fragment being displaced inward it goes outward. 
In this case as it rises it pushes the head and tilts it inward while it passes farther 
outward. 

The diagnosis is to be made by a careful examination and comparison with the 
opposite healthy member. The head is recognized to be in the glenoid cavity, 

^ — ^ Acromion process 

Supraspinatus muscle 



Clavicle 



Subscapularis 
muscle 



Pectoralis minor 
muscle 




Deltoid muscle 



Long head 
' of biceps 



Pectoralis 
major 



Pectoralis major 



Latissimus dorsi 
and teres major 



Fig. 261. — Fracture of the surgical neck of the humerus. The upper fragment is held out by the supra- 
spinatus, while the lower fragment is drawn in by the pectoralis major, latissimus dorsi, and teres major 
muscles and the arm abducted by the deltoid. 



crepitus is felt, the upper end of the lower fragment can often be palpated, and on 
rotating the arm the head of the bone is found to lie stationary. 

Treahnent. — The ideal treatment is extension with the patient in bed and the 
arm abducted. As the upper fragment cannot be brought in, an eflort may be 
made to bring the lower one out. As these are usually treated as walking cases a 
common dressing employed is a shoulder-cap with the arm bound to the side; some- 
times an axillary pad is used to keep the arm away from the body. In cases of 
fracture associated with luxation of the head of the bone, replacement can sometimes 
be effected by traction in the abducted position and pressure on the head, general 
anaesthesia being used (see description of direct method of reduction under dis- 
location of the shoulder, page 236). 



THE SHOULDER-GIRDLE. 



247 



To aid in the reduction McBurney devised a hook which he inserts into the upper 
fragment, puUing it toward the glenoid cavity. 



Supraspinatus 
Muscle 



EPIPHYSEAL SEPARATIONS. 

The epiphyses that are hable to separation are those of the coracoid process, 
the acromion process, and the upper end of the humerus. 

Separation of the Coracoid Epiphysis. — The coracoid process has three 
separate centres of ossification which fuse with the body of the bone from the fifteenth 
to the twentieth year. Therefore displacements occurring before the latter age may 
be separations of the epiphysis and not true fractures, particularly if the line of sepa- 
ration runs through the base of the coracoid. 

Separation of the Acromion Epiphysis. — The acromion process is cartilag- 
inous up to the fifteenth year. Then two centres appear and the epiphysis unites 
with the rest of the spine of the scapula about the twentieth year or later. The epi- 
physeal line runs posterior to the acromioclavicular joint, just behind the angle of the 
spine of the scapula. It has been suggested that many cases diagnosed as sprains and 
contusions of the shoulder are really epiphyseal separations of the acromion process. 

Separation of the Epiphysis of the Upper End of the Humerus. — The 
upper end of the humerus has three centres of ossifica- 
tion, one for the head and one each for the greater and 
lesser tuberosities. These three centres are blended by 
the seventh year, and the whole epiphysis unites with the 
shaft at about the age of twenty-five years. 

The epiphyseal line follows the lower half of the 
anatomical neck and then passes outward to the insertion 
of the teres minor muscle. This brings the outer end of 
the epiphyseal line some distance away from the joint, 
while the inner portion of the line is within the joint. 
Disease of this region may therefore follow the epiphyseal 
cartilage into the joint. A separation of the epiphysis 
from injury will implicate the joint. 

The surgical neck of the humerus lies a short dis- 
tance below the epiphyseal line and farther away on the 
outer side than on the inner. The line of the epiphysis 
rises higher in the centre of the bone than on the sur- 
face, making a sort of cap for the end of the diaphysis. 
The symptoms of epiphyse&l separation are almost 
exactly the same as those of fracture of the surgical neck 
(see page 245). 

The supraspinatus is the main agent in tilting the 
upper fragment outward, while the muscles inserted into 
the bicipital ridges, — the pectoralis major into the outer 
ridge and the latissimus dorsi and teres major into the 
inner, — draw the lower fragment inward. The relative 
position of the fragments when the lower is displaced outward is seen in Fig. 262. 

AMPUTATIONS AND RESECTIONS OF THE SHOULDER. 
AMPUTATION AT THE SHOULDER-JOINT. 

The many different methods of amputating at the shoulder may for our purposes 
be divided into two classes, — the flap method and the racket method. 

The Flap Method. — One large flap may be made to the outer side and a 
short one to the inner side (Dupuytren) or they may be made anteroposteriorly 
(Lisfranc). The flap operations were done with long knives by transfixion, as they 
originated before the discovery of general anaesthesia and by them the member was 
removed with great rapidity (Fig. 263). 

In DupuytrerCs method the arm was raised to a right angle with the body and the 
deltoid muscle grasped with one hand while the knife was inserted beneath it, entering 




Fig. 262. — Detachment of the 
epiphysis of the upper end of the 
humerus. 



248 



APPLIED ANATOMY. 



just below the posterior portion of the acromion process (its angle) then passing 
under the acromion to emerge in front at the coracoid process. This flap was turned 
up, the capsule and muscles divided, the bone turned out, and while an assistant 
compressed the remaining tissues they were divided transversely. 

Lisfrand s method consisted in transfixing the posterior axillary fold from below 
upward, entering the knife in front of the tendons of the latissimus dorsi and teres 
major muscles and bringing it out a litde in front of the acromion. The joint 
was opened posteriorly, the bone luxated, and an anterior flap cut from within out- 
ward. Sir William Fergusson, probably the most skilful operator of his day, was 
partial to this operation. 

The Racket Method. — In this method the incision resembles in shape the 



Coraco- Long Acro- 

acromial head of mion 

ligament biceps process 



Deltoid 
muscle 



Supraspinatus 



Infraspinatus 



Teres minor 




Coracobrachialis and 
short head of biceps 

Musculocutaneous 
nerve 
Median nerve 

Internal cutaneous nerve 



Musculospiral 
(radial) nerve 



Posterior circumflex 
artery 

Subscapular artery 
Latissimus dorsi and 
teres major 
Ulnar nerve 



Fig. 263. — Amputation of the shoulder by anteroposterior flaps. The upper extremity of the incision passes 
between the coracoid and acromion processes. The posterior flap is the larger. 



ordinary racket, such as is used in tennis. The loop encircles the arm, while the 
handle begins above at the point of the shoulder. 

There are two operations by the racket method, which differ as to the position 
from which the upper portion of the incision starts. 

Larrey s Method. — The operation usually ascribed to Larrey consists in starting 
the incision at the anterior end of the acromion process and continuing it straight 
down the arm for three centimetres (i^^ in. ). It then parts, one branch sweeping 
gradually in a curved line to the anterior axillary fold and the other to the posterior 
axillary fold, an incision, through the skin only, passes across the inner surface of the 
arm joining the two branches. The flaps having been turned anteriorly and poste- 
riorly, the joint is opened by cutting on the head of the bone, first posteriorly, then 
above, and then anteriorly. Tilting the head outward the inferior portion of the 
capsule is divided and the bone loosened from the soft parts. These are com- 
pressed by the fingers of an assistant and cut. 



THE SHOULDER-GIRDLE. 249 

Spence' s Method. — A modification of Larrey's procedure, attributed to Spence 
by the British and to S. Fleury by the French, consists in commencing the incision 
just outside of the coracoid process in the interval between it and the acromion 
process. This modification is probably the best form of procedure for this locality 
and is the one which will be discussed here. It will be noticed, however, that it 
practically changes the operation of Larrey from one with anteroposterior flaps to one 
with a single external flap, as in the method of Dupuytren. (Fig. 263). 

The incision begins just below the coraco-acromial ligament and lies deep in the 
hollow formed by the anterior concave surface of the outer third of the clavicle. It 
divides the fibres of the deltoid muscle longitudinally a short distance from its anterior 
edge. It will be recalled that the deltoid muscle covers the coracoid process and 
extends just to its inner side to be attached to the outer third of the lower surface 
of the clavicle. Between it and the adjoining edge of the pectoralis major muscle 
runs the cephalic vein. This passes downward and outward along the inner edge 
of the deltoid until it reaches the outer edge of the biceps muscle alongside of which 
it passes down to the elbow. This vein will be cut as the inner branch of the 
incision is made. The bicipital groove, when the palm of the hand faces forward, 
lies almost directly below the coraco-acromial ligament. While the incision is being 
made the arm is kept rotated slightly outward. 

As the knife descends it runs along the inner side of the bicipital groove and 
divides the tendon of the pectoralis major muscle. As soon as this tendon is cut the 
incision is inclined laterally. The incision having been carried down to the bone, 
except on the inside of the arm, the deltoid flap is raised upward and backward. It 
carries with it the circumflex nerve and posterior circumflex artery. 

The disarticulation of the bone is apt to be bungled unless one knows the con- 
struction of the parts. It is to be borne in mind that the capsular ligament is to be 
divided together with the tendons of the muscles inserted into the tuberosities. The 
capsule does not pass across the anatomical neck to be inserted into the tuberosities 
beyond, and the mistake is often made of cutting on the anatomical neck and there- 
fore frequently the capsule still remains attached to the proximal side. The cut 
may be commenced posteriorly and should be made on the head of the bone just 
above the anatomical neck. The arm is to be adducted and rotated inward and the 
muscles inserting into the greater tuberosity cut in their order, first the teres minor, 
then the infraspinatus and supraspinatus with the joint capsule beneath them. Then 
comes the long head of the biceps, and the arm now being rotated outward, the 
tendon of the subscapularis is divided. In cutting the muscles and capsule across 
the top of the joint, the arm is to be kept close to the side of the body so as to tilt 
the upper portion of the capsule out beyond the acromion process. 

The head of the bone can now be drawn out sufficiently to allow the knife to be 
introduced behind it to divide the inferior portion of the capsule. This should be 
detached close to the bone so as to avoid wounding the axillary artery and especially 
the posterior circumflex artery and the circumflex nerve, which wind around the 
surgical neck immediately below and are to be pushed out of the way. 

The division is completed by cutting the remaining muscles passing from the 
trunk to the shaft of the bone. On the inner side may be an uncut portion of the 
pectoralis major, the coracobrachialis, and short head of the biceps ; below is the long 
head of the triceps and on the outer side are the teres major and latissimus dorsi. 

On examining the face of the stump, posteriorly is seen the bulk of the deltoid 
muscle with the triceps below, and then the latissimus dorsi and teres major tendons 
lying next to the artery. Anteriorly is the cut edge of the deltoid and pectoralis 
major with the coracobrachialis and short head of the biceps lying next to the artery. 

To the outer side of the artery lie the median and musculocutaneous nerves. 
To the inner side are the ulnar and lesser internal cutaneous nerv^es (cutaneus brachii 
medians') and the axillary vein. Posteriorly are the musculospiral and axillary 
(circumflex) nerves. 

Sometimes the median nerve lies in front instead of to the outer side. The axillary 
artery is divided below the origin of the anterior and posterior circumflex arteries. 
The bleeding in the first cut will be from the cephalic vein (which runs between 
the pectoralis major and deltoid), muscular branches of the posterior and anterior 



250 



APPLIED ANATOMY. 



circumflex, a small ascending branch of the anterior circumflex which runs in the 
bicipital groove, and the humeral branch of the acromial thoracic which accompanies 
the cephalic vein. 

A glaring and common mistake in the performance of shoulder amputations is 
the making of the flaps entirely too short, especially when a Larrey operation is 
attempted. 

The avoidance of serious hemorrhage is usually accomplished by clamping the 
small vessels as the operation proceeds, and before the final division of the axillary 
vessels slipping the fingers behind the bone and compressing them. 

Esmarch's tube has been used by encircling the shoulder as close to the trunk 
as possible, the tube being kept from slipping by a bandage passed beneath it and 
fastened to the opposite side. Wyeth's pins have been used for the same purpose. 
One is inserted through the lower edge of the anterior axillary fold a little internal 
to its middle and brought out above in front of the acromion process, the other is 
entered at a corresponding point of the posterior fold and brought out above just 
behind the angle of the spine of the scapula or acromion process. 

Interscapulothoracic Amputation. — For malignant growths of the axilla, 
shoulder, or scapula, and, rarely, for injury, the whole upper extremity with the 

Cords of brachial plexus 

Subclavian artery 

Superficial cervical artery 
Trapezius 

, Posterior scapular artery coming 
Omohyoid muscle— ^^[^^'^■Hi^^'^B^^y / from the subclavian 

" ^BP>^ ^^^/^^^^^^^^B^^^^M||^B^^^^^^ Costocoracoid ligament 
Scalenus anterior SBk^lk/ ^^H^^^^^^^^^^^^^WSIfev^ / Deltoid 

muscle 

Transverse cervical 
artery 

Internal jugular 

Phrenic nerve 

Suprascapular artery 

Thoracic duct 

Innominate \ 
vein 



Subclavius muscle 



Subclavian vein 

Acromial thoracic artery 

Fig. 264. — Structures exposed by excising the inner portion of the clavicle. 




scapula and part or whole of the clavicle have been removed. Anteroposterior 
flaps are made. 

The greatest danger is death from shock and hemorrhage. In order to obtain 
some idea of the topography and vessels involved, see Fig. 264. 

Excision of the Clavicle. — Excision of the clavicle in the living body, like 
tracheotomy, is much more difficult than when practiced on the dead body; this 
is due to the condition of the parts for which operation is undertaken. It has been 
often excised for malignant growths. On the upper anterior surface are attached the 
clavicular origin of the sternomastoid, the deep cervical fascia, and the trapezius 
muscle. Crossing the clavicle near its middle is the jugulocephalic vein which some- 
times connects the cephalic with the external jugular. It is likewise crossed by the 
superficial descending branches of the cervical plexus. The external jugular vein, 
about 2.5 cm. (i in.) above the middle of the clavicle, pierces the deep fascia and 
turns inward to empty into the internal jugular just behind the outer edge of the 
sternomastoid muscle; just below it empties the thoracic duct at the junction of the 
internal jugular and subclavian veins. The subclavian vein is directly behind the 
clavicle and the left innominate vein crosses behind the left sternoclavicular joint and 
passes across the posterior surface of the sternum just below or on a level with its 



THE SHOULDER-GIRDLE. 251 

superior border. The omohyoid muscle, if the shoulder is drawn outward and the 
head turned to the opposite side, is drawn upward above the clavicle. 

Behind the upper portion of the clavicle is the suprascapular artery and above 
it runs the transverse cervical artery, a branch of the thyroid axis. Both these 
vessels cross over the scalenus anterior muscle on which, toward its inner edge, is 
lying the phrenic nerve. In front of the scalenus anterior runs the subclavian vein 
and behind it is the subcla\'ian artery with the cords of the brachial plexus abo\'e 
and to its outer side. Below and in front are attached the pectoralis major and 
deltoid muscles; the space between them forms the subclavicular triangle and occu- 
pies the outer half of the middle third of the bone. The cephalic vein pierces the 
costocoracoid membrane at this point to enter the subclavian vein. 

On the under surface of the bone is the subclavius muscle, covered with a 
strong membrane. To the inner side of this muscle is the costoclavicular ligament. 
Beneath the clavicle, about its middle, passes the subclavian artery, separated from 
the vein in front by the scalenus anterior muscle. Below and beneath the subclavian 
artery, which rests directly on it, is the pleura. The internal mammary artery passes 
behind the inner extremity of the clavicle opposite the cartilage of the first rib. 

The clavicle is the first bone in the body to ossify, and it has one epiphysis at 
its sternal end which appears about the seventeenth year and joins the shaft from 
the twentieth to the twenty-fifth year. In removing the bone it is first loosened at 
its outer extremity by dividing the acromioclavicular and coracoclavicular (conoid 
and trapezoid) ligaments. 

Excision of the Scapula. — The removal of the scapula necessitates the 
division of a large number of muscles, for which see pages 226 and 227. The sub- 
scapular artery at the anterior border, about 2. 5 cm. ( i in. ) below the head or glenoid 
process, and the suprascapular at the suprascapular notch, are to be ligated before 
removing the bone. Skirting the posterior edge is the posterior scapular, the 
continuation of the transverse cervical artery; it is to be avoided when detaching 
the muscles. The acromial branches of the acromial thoracic artery ramify over the 
acromion process; they are not so large as those already mentioned. 

Mr. Jacobson suggests that if safety permits one should allow the acromion 
process to remain, as it preserves the point of the shoulder and to some extent, the 
functions of the trapezius muscle. 

Excision of the Head of the Humerus.— The incision for the removal 
of the head of the humerus should be commenced just outside of the coracoid 
process and be carried 10 cm. (4 in. ) downward in a direction toward the middle 
of the humerus, where the deltoid inserts. This incision may be made while the arm 
is somewhat abducted but it does not go in the groove between the deltoid and 
pectoralis major muscles. This groove contains the cephalic vein and the humeral 
branch of the acromial thoracic artery, and hence is to the inner side of the coracoid 
process and as the incision is to the outer side, it passes through the deltoid near 
its anterior edge (Fig. 265). 

The incision goes through the muscle and exposes the capsule of the joint. The 
sides of the wound are to be retracted and, if the long head of the biceps muscle is 
not recognized by sight, the finger is inserted and the arm rotated. The bicipital 
groove can be felt and the tendon identified. 

The capsule is to be incised along the outer edge of the long tendon of the 
biceps and as the arm is rotated inward the supraspinatus, infraspinatus, and teres 
minor muscles are to be detached from the greater (posterior) tuberosity. The 
biceps tendon is again brought into view by rotating the arm outward and its sheath 
(transverse ligament) slit up and the tendon luxated inward. 

The attachment of the capsule and subscapularis muscle to the lesser (anterior) 
tuberosity is then divided while the arm is rotated outward. The biceps tendon lies 
in the bicipital groove between the two tuberosities. When the arm is lying with the 
palm upward, in a supine position, the bicipital groove looks directly anteriorly in a 
longitudinal line passing midway between the two condyles of the lower end. The 
position of the head and groove can be told by observing the position of the condyles. 
The head is directly above the internal condyle and the groove is on rhe anterior sur- 
face above a point midway between the condyles. After the capsule has been opened 



252 APPLIED ANATOMY. 

and the attachments of the muscles to the greater and lesser tuberosities divided and 
the tendon of the biceps luxated inward, the head is thrust directly upward and out 
of the wound and sawed of^ as low as desired. 

Immediately below the lower edge of the tuberosities is the surgical neck. On 
it anteriorly winds the anterior circumflex artery, and posteriorly the circumflex (axil- 
lary) nerve and posterior circumflex artery. These should not be disturbed, for the 
artery will bleed and injury of the nerve will cause paralysis of the deltoid muscle. 

Posterior and transverse incisions have been suggested for this operation but 
they are not to be advised. The circumflex nerve and posterior circumflex artery 
are almost certain to be injured and the functions of the deltoid are liable to be 
seriously impaired or altogether lost. 

If more access is desired than can be obtained by a straight incision as directed, 
the deltoid can be detached from its origin along the outer end of the clavicle and 



Coracoid process 




Acromion process 

Subscapularis tendon and capsule 
/ ;,, - y' Lesser tuberosity 
Deltoid muscle 



Bicipital groove 



Ftg. 26s. — Resection of the shoulder- joint. The arm has been rotated outward so as to put the tendon of the 
subscapularis on the stretch. The long tendon of the biceps has been dislocated from the bicipital groove and is 
held to the inner side by a hook. 

acromion process and turned down. This does not interfere with its nerve supply. 
The circumflex nerve going to the muscle crosses the humerus at about the junction 
of the upper and middle thirds of the deltoid or a finger's breadth above its middle. 
After resection of the bone the deltoid can again be brought up and sewed to its pre- 
vious attachment. 

The character of the operation depends on the nature and extent of the disease. 
The operator should be familiar with the epiphyseal line, which runs from the inside 
upward and outward in the line of the anatomical neck as far as the middle of the 
bone, and then slopes slightly downward and outward to reach the surface almost on 
a level with the lower (inner) edge of the articular surface. As this is the site of 
most active growth of the humerus in young subjects this epiphyseal cartilage should 
be spared as much as possible. 

The disability arising from a free resection is so great, owing to the loss of 
movements resulting from the detachment of muscles and interference with the 
epiphyseal cartilage, that formal resections are rarely performed, but, instead, the 
diseased parts are simply gouged away and as much allowed to remain as possible. 



THE SHOULDER GIRDLE. 



253 



It is to be remembered that rotation inward is mostly performed by the sub- 
scapularis and outward rotation by the infraspinatus and teres minor. The supra- 
spinatus aids abduction. A too free excision is liable to be followed by a flail-joint, 
in which case the limb hangs helplessly by the side with the dorsum pointing forward. 

The axillary fold muscles insert on the anterior surface of the bone and hence 
turn the arm inward and draw it in toward the body, they do not compensate for 
the loss of the muscles attached to the tuberosities. 

The bleeding in the operation will be mainly from the acromial branches of the 
acromial thoracic artery and the bicipital branch of the anterior circumfiex artery, 
which runs in the bicipital groove. 

DISEASES OF THE JOINT AND BURS^. 

The shoulder-joint, like other joints, is subject to inflammatory and other diseases. 
These may be (i) traumatic and later septic; (2) rheumatic or gouty; (3) tuberculous, 
with suppuration. 

These affections result in an eflusion \yithin the joint-cavity which distends the 
capsule and finally tends to escape at the weakest points. The joint is not a 



Supraspinatus 



Acromion process 

Subacromial bursa space 



Capsule of joint 
Long head of biceps 




Capsule of joint 



Glenoid cavity 



Long head of triceps 



Fig. 266. — Transverse section of shoulder-joint, illustrating the laxity of the capsule of the joint. 



complicated one, like the knee, and its synovial membrane is neither so extensive 
nor so elaborate. 

Traumatism may give rise to a synovitis, an inflammation of the synovial mem- 
brane, or an arthritis involving the entire joint structures. Sprains and other injuries 
are not uncommon. A sprain will be caused by a force which acts to a greater 
extent than the normal movements of the joint will allow. 

Movements of the Joint. — In abduction the capsule becomes tense at its lower 
portion when the arm is at 90 degrees to the trunk, greater abduction is resisted by the 
greater tuberosity impinging on the acromion process and the scapula begins to revolve. 

Adduction is resisted both by the muscles and by the ligaments. When the 
ligaments only remain, the head can be separated for 2 cm. or more from the glenoid 
cavity (see Fig. 266). Marked adduction is usually limited by the arm coming in 
contact with the side of the body. 

If the humerus is brought diagonally across the chest the scapula begins to 
move and its posterior edge and lower angle turn forward. As the humerus is 
adducted the deltoid and supraspinatus are made tense and the head is drawn up in 
its socket. When the muscles are paralyzed the weight of the upper extremity 
allows the head to fall and a distinct depression can be seen beneath the acromion 
process. In paralysis of the deltoid this is particularly noticeable. 



254 



APPLIED ANATOMY. 



If traction is made on the arm, the muscles are the resisting agents. If the arm 
is in a position of adduction, those going from the humerus to the scapula, as the 
deltoid, supraspinatus, biceps, and triceps, act. If in abduction, then also those 
from the humerus to the trunk, like the pectoralis major and latissimus dorsi, are 
brought into play. The part played by the deltoid and trapezius should be noted. 
If the arm is down by the side and traction is made on it, the force is transmitted 
from the humerus in a direct line through the deltoid and the upper fibres of the 
trapezius to their attachment to the spine and superior curved line of the occiput. 
If, on the contrary, the traction is made while the arm is raised above the level of the 



Superior acromioclavicular ligament 



Tendon of supra 
spinatus muscle 



Acromion proces 




Clavicle 



Conoid ligament 
Trapezoid ligament ' 

Coraco- acromial ligament 
Coracoid process 

Coracohumeral ligament 
Coracobrachialis muscle 
Short head of biceps 



Long head of biceps 



Pectoralis major muscle 



Fig. 267. — Acromioclavicular and shoulder joints. 

shoulder, the force is transmitted through the axillary fold muscles as well as by the 
deltoid and continued through the lower fibres of the trapezius. In either case the 
muscles are the resisting agents and not the ligaments. Abduction to more than a 
right angle is resisted by the contact of the greater tuberosity with the under surface 
of the acromion process and coraco-acromial ligament and the under side of the cap- 
sular ligament is made tense. The raising of the arm to 90 degrees is performed 
by the supraspinatus and deltoid muscles of the scapula and beyond this by the 
serratus anterior and other muscles. 

Inward rotation is limited by the infraspinatus and teres minor muscles and by 
tension of the upper portion of the capsule. Outward rotation is limited by the sub- 
scapularis and upper portion of the capsule. The humerus rotates on its long axis 
97° (Macalister). 



THE SHOULDER-GIRDLE. 255 

Subacromial Bursa. — Separating the greater tuberosity from the deltoid 
muscle, the acromion process, and coraco-acromial ligament, is the large subacromial 
bursa. It does not communicate with the joint, except rarely in old people. Effu- 
sions into it cause an increased prominence of the deltoid muscle, and pus seeking 
an outlet is likely to show itself at the anterior edge of the muscle and less often at 
its posterior edge. These effusions, which are liable to be present from contusions, 
sprains, etc. , should not be mistaken for intra-articular accumulations. 

Biceps Tendon. — The long tendon of the biceps muscle enters the joint 
through the bicipital groove between the two tuberosities. With the arm hanging 
by the side it points directly forward; it passes over the head of the humerus and 
under the coraco-acromial ligament about midway between the coracoid and acro- 
mion processes to insert into the upper edge of the glenoid cavity. It is covered 
by a synovial sheath which passes with it through the opening in the capsule and a 
short distance along the bicipital groove. As this sheath does not communicate with 
the joint the tendon is in one sense extra-articular. It is held in the groove by a 




Injection following the 
long tendon of the biceps 



Prolongation under the tendon 
of the subscapularis muscle 



Fig. 26S. — Shoulder- joint distended with injection, showing the position assumed by the humerus. 



fibrous expansion, extending from the pectoralis major tendon below to the capsule 
above, called the tra7isverse fnwieral ligament. This ligament is so strong that luxa- 
tion of the tendon is uncommon; even when the humerus is luxated the tendon is 
rarely displaced. 

Subscapular Bursa. — Beneath the tendon of the subscapularis there is a bursa 
which frequently communicates with the joint. This opening tends to weaken the 
capsule and it is at this point and just below that the head bursts through in disloca- 
tions. 

Infraspinatus Bursa. — The capsule of the joint and the synovial membrane 
may be prolonged beyond the rim of the glenoid cavity under the tendon of the 
infraspinatus, or a bursa at this point may communicate with the joint. 

Other bursae may be present, but are unimportant. One is between the 
coracoid process and the capsule and another under the combined tendon of the 
coracobrachialis muscle and the short head of the biceps. 

Effusions in the Shoulder-joint. — Liquid accumulations occur both from 
injury and disease. The liability of confounding them with those in the subacromial 
bursa has been alluded to above. As a result of disease, most often osteo-arthritis or 
tuberculosis, considerable liquid may accumulate in the joint. As the tension in- 
creases the arm becomes abducted about 50 degrees and the effusion tends to escape 
through the openings in the capsule (Fig. 268). 



2 56 APPLIED ANATOMY. 

A distention of the joint will cause the "deltoid to be more prominent. If the 
affection is in an old person, as is liable to be the case in osteo-arthritis, there 
is apt to be a communication with the subacromial bursa and this will become dis- 
tended. If the liquid is purulent it has a tendency to work its way laterally under 
the deltoid and break through at its anterior or posterior borders and show itself at 
the folds of the axilla. 

In osteo-arthritis {arthritis deformafis^ the long tendon of the biceps as it passes 
through the joint may be dissolved and the belly of the muscle then contracts and forms 
a lump on the middle of the arm anteriorly. 

Pus frequently finds an exit along the bicipital groove and follows it downward 
and shows itself just at the edge of the anterior axillary fold near the middle of the arm. 

If the pus passes out by way of the subscapular bursa it passes below the 
subscapular tendon and into the axilla anteriorly. If it passes backward it may 
emerge through the bursa beneath the infraspinatus muscle, and then either work its 
way downward into the posterior portion of the axilla, or if it works upward may 
travel either above or below the spine of the scapula and show itself on the dorsum. 

THE AXILLA. 

The axilla is a wedge-shaped space with its apex upward, formed between the 
arm and chest at their junction. It serves as a passage-way for the arteries, veins, 
nerves, and lymphatics passing between the trunk and the upper extremity. It is 
frequently the site of growths and abscesses, requiring operations which necessitate a 
knowledge especially of its blood-vessels and lymphatics. 

Extent. — Its apex lies between the clavicle and scapula above and the first rib 
beneath. Its base is formed by the skin and fascia stretched between the anterior and 
posterior axillary folds. It is spoken of as having four walls: inner, outer, anterior, 
and posterior. 

The inner wall is formed by the first four ribs and interspaces and the corres- 
ponding serrations of the serratus anterior (magnus) muscle. 

The outer wall is nothing more than the chink formed by the union of the two 
axillary folds. Above is the lesser tuberosity of the humerus and subscapularis ten- 
don, lower down are the coracobrachial and biceps muscles. 

The anterior wall is formed by the pectoralis major and minor muscles with the 
fascia enveloping them. 

The posterior wall is formed by the subscapularis above and the teres major and 
latissimus dorsi muscles below. 

Axillary Fascia. — The name axillary fascia is given to the fascia which closes 
the axillary space and forms its base. It is stretched across from the lower edge of 
the pectoralis major in front to the lower edge of the teres major and latissimus dorsi 
behind. On the inner wall it is continuous with the fascia covering the serratus 
anterior (magnus) and side of the chest; when it reaches the vessels at the apex of 
the axilla it is reflected around them to form the sheath. 

On the outer wall it passes from the pectoralis major in front, over the coraco- 
brachialis muscle beneath, blends with the sheath of the vessels, and then passes to 
the posterior wall, covering the subscapularis above and the teres major and latissi- 
mus dorsi below. At the lower edge of this latter muscle, which is a little lower than 
the pectoralis major, it passes across the axilla (Fig. 269). 

Anteriorly the fascia covers the pectoralis major muscle; at its lower edge it 
splits to cover the pectoralis minor muscle and forms a sheath for it. As the axillary 
fascia approaches the apex of the axilla where the superficial vessels enter, it becomes 
cribriform in character, the fascia itself being wide-meshed and containing fat in the 
interstices. If the handle of the scalpel is inserted in the apex of the axilla and 
worked backward and forward two arches of fascia are readily formed, one convex 
toward the chest, and called the " Achselbogen," and the other convex toward the 
arm, called the "Armbogen" (Langer, Oester. med. IVoch., 1846, Nos. 15 and 16). 

The fascia on the superficial surface of the pectoralis minor is called the clavi- 
pedoral fascia. At the upper or inner border of the pectoralis minor it is continuous 



THE AXILLA. 257 

with the costocoracoid membrane which goes up to the clavicle, where it splits to 
enclose the subclavius muscle and to be attached to the anterior and posterior borders 
of the clavicle. The upper portion of this costocoracoid membrane is thickened and 
forms a firm band which runs from the coracoid process to the cartilage of the first 
rib, and is called the costocoracoid ligament. 

Between this ligament above and the upper edge of the pectoralis minor below, 
and piercing the costocoracoid membrane, are the acromiothoracic artery and vein, 
the cephalic vein, the superior thoracic artery, external anterior thoracic nerve, and a 
few lymphatics derived from the breast. The superior thoracic artery is often a 
branch of the acromiothoracic and passes behind the vein to supply the serratus 
anterior and intercostal muscles and side of the chest. 

The fascia on the under surface of the pectoralis minor unites with the layer on 
its upper surface, and passes upward to the coracoid process and is reflected onto the 



Pectoralis major 

\ 4P^'^", 

^ Axillary arch 



*'^, 



fl®**' 





Intercostohumeral nerve 



Teres major and latissimus dorsi 



Fig. 269. — Axillary fascia. At the apex of the axilla the fascia is almost lacking, forming a curved arch on 
the side toward the chest, called the axillary arch or " Achselbogen." The curved edge toward the arm, less dis- 
tinct than that toward the chest, is called the " Armbogen." 

vessels to aid in forming their sheath. It is continuous with the fascia on the under 
surface of the subclavius muscle and the deep fascia of the neck. 

This portion of the fascia is not sufficiently strong to form an absolute barrier 
between the neck and axilla, consequently abscesses forming in the neck will break 
through it and passing under the clavicle appear in the axilla, and abscesses starting 
in the axilla may burrow under the clavicle and up beneath the deep fascia of the neck. 

THE AXILLARY VESSELS. 

The axillary artery and vein are both important. The avoidance of hemorrhage 
in operations in this locality requires skill and knowledge, and venous bleeding is 
more apt to be troublesome than arterial. Wounds of the vessels, whether artery 
or vein, of those portions of the body like the axillae, groins, or base of the neck are 
particularly dangerous; the blood current is both large and rapid. 

The axillary vein drains the whole upper extremity and part of the chest, while 
the axillary artery carries all the blood going to those parts. The veins being so 
much weaker and thinner walled than the arteries is the reason of their being more 
frequently injured. Ligation of the artery, or vein, or both, may cause gangrene of 
the extremity and require amputation. 

The Axillary Artery. — The axillary artery begins at the lower border of the 
first rib and ends opposite the lower border of the folds of the axilla (teres major). 
If the arm is lying by the side of the body the artery describes a curve with its 
17 



258 



APPLIED ANATOMY. 



convexity outward. If the arm is placed straij^ht out away from the body, the artery 
is straight. If the arm is abducted above the level of the shoulder, the artery again 
becomes curved but with its convexity downward. 

The line of the artery is straight only when the arm is out from the body, when 
its course is represented by a line drawn from the middle of the clavicle to the 
anterior surface of the elbow, midway between the two condyles. It passes down 
along the inner side of tht coracoid process and the coracobrachialis muscle about at 
the junction of the anterior and middle thirds of the axilla. It is divided into three 
parts by the pectoralis minor muscle (Fig. 270). 

First Portion. — The first portion of the axillary is usually stated to be 2.5 cm. 
(i in.) in length, and for surgical purposes we may accept this as a working basis. 

A. H. Young has pointed out that, with the arm out from the body, the upper 
border of the pectoralis minor is nearly or quite level with the lower border of 
the first rib, but the muscle leaves the side of the chest to go to the coracoid 
process and that makes an interspace, more than 2. 5 cm. long, above its upper edge 

Pectoralis major 
Deltoid 



Biceps 




Coracobrachialis 
Groove for axillary vessels and nerves 
Long head of triceps muscle 

Teres major and latissimus dorsi muscles 



Fig. 270. — Line indicating the course of the axillary artery. 

and between it and the lower edge of the subclavius muscle, in which the artery can 
be ligated. In the first portion the axillary artery above the pectoralis minor lies too 
deep to be compressed, being on a lower level than the pectoralis major, therefore 
it is better to compress the subclavian above the clavicle. 

Branches. — The first portion of the axillary gives of? two branches, the superior 
thoracic and the acromiothoracic (thoraco-acromialis) (Fig. 271). 

The superior thoracic comes of? posteriorly and winds around behind the axillary 
vein to supply the under surface of the pectoralis minor, intercostal muscles, serratus 
anterior, and side of the chest. It is a small vessel. 

The acromiothoracic (thoraco-acro?nialis) is a short large trunk which comes of? 
anteriorly, winding around the edge of the pectoralis minor and piercing the costo- 
coracoid membrane to divide into four branches: an acromial, to the acromion 
process; a humeral, which follows the cephalic vein between the deltoid and pecto- 
ralis major; a pectoral, which supplies the under surface of the pectoralis major and 
gives branches to the mammary gland; and a clavicular, to supply the subclavius 
muscle. 

Relations. — Posteriorly^ the artery lies on the first intercostal space and 
muscle, the second and part of the third serrations of the serratus anterior, the pos- 
terior thoracic nerve (or external respiratory of Bell), and the internal anterior 
thoracic nerve to the pectoralis minor and major. 



THE AXILLA. 



259 



Internally. — ^To the inner side of the artery and somewhat anteriorly is the 
axillary vein; between the two runs the internal anterior thoracic nerve. As the 
artery and vein ascend they become separated, the artery to pass behind and the 
vein in front of the scalenus anterior muscle. 

Externally. — To the outer side and above the artery lie the cords of the 
brachial plexus. 

Anteriorly. — In front of the artery are the skin and superficial fascia, the edge 
of the pectoralis major muscle and fascia covering it, the costocoracoid membrane 
pierced by the acromiothoracic artery, cephalic vein, and external anterior thoracic 
nerve, which goes to supply the pectoralis major muscle. 

Ligation of the First Portion of the Axillary Artery. — The artery lies 
deep in the infraclavicular triangle, between the pectoralis major and deltoid muscles. 
It can be approached by either a transverse or a longitudinal incision. If the former 
is used it should be made through the skin only, immediately below the clavicle, 
reaching from just outside the sternoclavicular joint to the coracoid process. 

The pectoralis major is detached from the clavicle and pushed downward, it 
arises from its inner half. This exposes the costocoracoid membrane. At the outer 



Pectoralis minor 



Pectoralis major 



Biceps 




Pectnralis major muscle 
Superior thoracic 



Acromiothoracic 



- — Long thoracic 



•Alar thoracic 



Subscapular 

., , \ Posterior circumflex 

Anterior V . \ 

circumflex N^ Latissimus dorsi 
Triceps 
Fig. 271. — Diagrammatic view of axillary artery and its branches. 

angle of the wound the cephalic vein and acromiothoracic artery are to be found. 

The deltoid muscle is to be detached or pushed outward to expose the coracoid 
process, this being recognized, the costocoracoid membrane is to be opened to its 
inner side, between it and the cephalic vein. The acromiothoracic artery if isolated 
will lead to the artery, while the cephalic vein goes direct to the subclavian vein. 
The vein and costocoracoid membrane are closely united and great care is necessary 
to avoid wounding the former in opening the latter. The cords of the brachial 
plexus are to the outer side of the artery and care is to be exercised not to mistake 
one of them for the artery. As the vein is the most dangerous structure, it is to be 
displaced inward and the aneurism needle passed between it and the artery from 
within outward. 

As the external anterior thoracic nerve is a nerve of motion supplying the 
pectoralis major muscle, if it is seen it should be avoided and not injured. 

If it is desired to use a longitudinal instead of transverse incision, it should com- 
mence just outside the middle of the clavicle and follow the groove between the deltoid 
and pectoralis major muscles downward for 10 cm. (6 in. ). Great care is then neces- 
sary to avoid wounding the cephalic vein and acromiothoracic artery, which lie in this 
groove. 

If sufficient exposure is not given by a single straight incision it can be supple- 
mented by one detaching the pectoralis major from the clavicle. 



26o 



APPLIED ANATOMY. 



Second Portion. — The second portion of the axillary lies beneath the pecto- 
ralis minor muscle. It is 3 cm. ( 1 1^ in. ) long and while never ligated at this point it is 
nevertheless frequently exposed while clearing out the axilla for malignant growths of 
the breast. Owing to its being covered by the pectoralis minor and major muscles 
the artery cannot be compressed at this point in its course. 

Branches. — Its branches are the alar thoracic and long thoracic. The alar tho- 
racic are small branches of little importance supplying the fat and glands of the 
axilla. 

The long thoracic or external mammary is of considerable importance on account 
of its size and because it is encountered in operations on the breast and axilla. It 
passes down along the lower (outer) border of the pectoralis minor, giving branches 
to it and the pectoralis major; some branches go to the axilla and serratus anterior, 
and others, which may be of considerable size in the female, wind around the lower 
portion of the pectoralis major or pierce it to supply the mammary gland. Posterior 



Pectoralis major 



Superior thoracic artery 



Acromiothoracic arte: 

Coracoid process- 

Peclotalis minor muscle 

Axillary artery. 

Axillary vein 

Alar thoracic artery 

Long head of bicepi 

Coracobrachialis and short 

head of biceps 

Musculocutaneous nerve 

Long thoracic artery. 
Anterior circumflex artery 
Subscapular artery 
Posterior circumflex artery 
Pectoralis major muscle 
Median nerve 

Internal cutaneous nerve 

Ulnar ner\'e 

Lesser internal 

cutaneous nerve 




Pectoralis minor 



I^tissimus dorsi 
Teres major muscle 
Intercostohumeral nerve 



Fig. 272. — Dissection of the axilla. 



to it is the long or posterior thoracic nerve, or external respiratory nerve of Bell, 
going to supply the serratus anterior muscle (Fig. 272). 

Relations. — Anteriorly is the pectoralis minor muscle, superficial to which is the 
pectoralis major and skin. Posteriorly lie the posterior cord of the brachial plexus, 
the fat of the axilla, and the subscapularis muscle; intcj'nally is the axillary vein, with 
the inner cord of the brachial plexus separating the two. Externally is the outer 
cord of the plexus and farther out is the coracoid process. 

Third Portion. — This is about 7.5 cm. (3 in.) long and runs from the lower 
border of the pectoralis minor to the lower border of the teres major. Its upper 
portion is under the pectoralis major but its lower portion is subcutaneous because 
the teres major, forming the edge of the posterior fold of the axilla, extends lower 
than the anterior fold. It is here that the axillary artery is most easily reached and 
most often ligated. 

Branches. — It gives of? three branches, the subscapular, the anterior circumflex, 
and the posterior circumflex. 

The subscapular artery is of considerable practical importance; it is the largest 
branch of the axillary and is given off opposite the lower border of the subscapularis 
muscle. It follows the lower edge of this muscle down the axillary or outer border 



THE AXILLA. 



261 



of the scapula to its angle, where it anastomoses with the posterior scapular, one of 
the terminal branches of the transverse cervical from the thyroid axis. 

Four centimetres ( I y^ in. ) from its origin the subscapular gives off the dorsalis 
scapiil(S, which is as large or larger than the continuation of the artery downward. 
The position of this artery should be borne in mind in operating. It winds around 
the outer edge of the scapula between it and the teres minor muscle to supply the 
muscles posteriorly. The subscapular artery is accompanied by the long subscapular 
nerve to its inner side. (The first or short subscapular nerve supplies the subscapu- 
laris muscle, the second supplies the teres major and the third or long subscapular 
supplies the latissimus dorsi muscle. ) 

The posterior axillary chain of lymph-nodes accompanies the subscapular artery, 
hence it is involved in operations for their removal. The point at which the dorsalis 
scapulae winds aroimd the axillary border of the bone is at or just above the level of the 
middle of the deltoid muscle and below the level of the posterior circumflex artery. 

The anterior circiunflex artery is comparatively insignificant. It winds ante- 
riorly around the surgical neck of the humerus beneath the coracobrachialis muscle 
and both heads of the biceps and gives off an ascending bicipital branch which ascends 
in the bicipital groove and a small descending branch to the tendon of the pectoralis 



Coracobrachialis muscle 



Median nerve 




Axillary artery 
Ulnar nerve 
Internal cutaneous nerve 



Fig. 273. — Ligation of the third portion of the axillary artery. 



major. As pointed out by Walsham, the anterior circumflex artery on account of 
the closeness with which it hugs the bone may be difficult to secure if wounded in the 
operation of resection of the humerus. 

The posterior circumflex artery is much larger than the anterior. It runs around 
the surgical neck posteriorly, below the teres minor, above the teres major, and 
between the long head of the triceps and the humerus. It is accompanied by the 
circumflex (axillary) nerve and they run transversely around beneath the deltoid 
muscle on a level with the junction of its upper and middle thirds. It is to avoid 
wounding these two important structures that the operation of resection is done 
anteriorly instead of posteriorly. Being covered only by the skin of the axilla and the 
superficial and deep fascias, it can readily be compressed by pressure directed out- 
wardly against the humerus along the inner edge of the coracobrachialis muscle. 

Relations. — Posteriorly the third portion of the axillary artery lies on the sub- 
scapularis, the latissimus dorsi, and teres major muscles, with the musculospiral and 
circumflex (axillary) nerves between the muscles and the artery. 

Anteriorly it is covered by the skin and fascia, the pectoralis major above, and 
deep fascia of the arm below. The inner root of the median nerve crosses it and 
sometimes the outer vena comes. 



262 



APPLIED ANATOMY. 



Acromiothoracic 



Posterior circumflex 
Anterior circumflex 
Subscapular 

Alar thoracic 



Externally is the coracobrachial muscle (which partly overlaps it and forms its 

guide), the main trunk and outer head of the median, and the musculocutaneous nerves. 

Inteffially is the axillary vein with the ulnar ner\'e between it and the artery. 

The internal and lesser internal cutaneous nerves also lie to its inner side with the 

former the more anterior. 

Ligation of the Third Portion of the Axillary Artery. — The arm being 
placed out from the body, palm upward, the incision for ligating the axillary artery in 
the third portion of its course is laid along the inner border of the coracobrachial 
muscle, at about the junction of the anterior and middle thirds of the axilla and on a 
line joining the middle of the clavicle and a point at the bend of the elbow midway 
between the two condyles of the humerus. 

The middle of the incision should be just above the lower edge of the folds of 
the axilla. The deep fascia having been opened, the coracobrachial muscle with the 

musculocutaneous nerve piercing it is 
pulled outward. Lying on the artery 
to its outer side is the median nerve; 
it is to be drawn outward. To the 
inner side lies the axillary vein with 
the ulnar nerve beneath it and the 
internal cutaneous nerve (cutaneus 
antebrachii medialis) in front of it 
close to the artery. 

The needle is passed from within 
outward. The artery at this point may 
be crossed by some muscular fibres 
coming from the latissimus dorsi and 
crossing the axilla. The axillary vein 
is the continuation of the basilic from 
the lower border of the teres major 
upward. 

Of the two venae comites of the 
brachial artery the inner one blends 
with the basilic at the lower border 
of the teres major; the outer one 
crosses the artery to empty into the 
axillary vein on the opposite side. 

The axillary vein receives the 
subscapular, circumflex, long thoracic, 
acromiothoracic, alar, and cephalic, 
and contains a pair of valves opposite the lower border of the subscapularis muscle. 
Collateral Circulation after Ligature of the Axillary Artery. — If the 
first portion of the axillary is tied, the acromiothoracic artery comes off so low down 
(under the edge of the pectoralis minor muscle almost) that the ligature is placed 
above it, in which case the collateral circulation is similar to that of the subclavian 
(see page 149). The second portion of the axillary, lying beneath the pectoralis 
minor, is not subject to ligation. In the third portion the subscapular and anterior 
and posterior circumflex arteries come off so close together that the ligature will be 
placed either just below or just above them (Fig. 274). 

If below, then the collateral circulation will be between them above and the 
superior profunda below. If above the subscapular, then the anastomosis would be 
as follows: 

Proximal Vessels. Distal Vessels. 

Acromiothoracic, acromial branch with anterior and posterior circumflex 

Acromiothoracic, humeral branch with anterior and posterior circumflex 

Acromiothoracic, pectoral branch with subscapular 

Long thoracic branch with subscapular 

Alar thoracic branch with subscapular 

Posterior scapular (branch of trans, cervical) with subscapular and dorsalis scapulae 

Suprascapular with dorsalis scapulae and posterior 

circumflex 




Superior profunda (arteria 
profunda brachii) 



Brachial artery 



Fig. 



-Collateral circulation after ligation of the third 
portion of the axillary artery. 



THE AXILLA. 



263 



Lymphatics of the Axilla. — There are two sets of lymphatic nodes in the 
axillary region, the axillary nodes proper and the subclavian nodes. 

The number of the nodes varies from about ten or twelve to twenty or more. 
When enlarged they are readily seen, but after the surgeon has carefully dissected 
away all the nodes he can possibly find disease may subsequently reveal the exist- 
ence of others. Hence it is impossible ever to be absolutely sure that all nodes have 
been removed. 

The subclavian nodes, about two or three in number, lie in the infraclavicular 
triangle between the pectoraUs major and deltoid muscles and on the front of the 
subclavian vein above the pectoralis minor muscle. They receive radicles from the 
mammary gland as well as from the axillary groups. 

The axillary nodes proper are composed of three sets, humeral or external, 
thoracic or anterior, and scapular or posterior, accompanying the three vessels, 
axillary, long thoracic, and subscapular. 

The humeral set, perhaps eight or nine, accompany the axillary artery and 
vein and lie along them and in the axillary fat. They receive mainly the lymphatics 



Deltopectoral node 



Brachial node 




Subscapular node 



Anterior pectoral node y- 

Vessel passing to anterior 

pectoral node 



Inferior pectoral node 



Subclavian node 



Vessel passing to 
subclavian node 



Intermediate node 



Subareolar plexus 
over mammary 
gland 



Fig. 275. — Lymphatics of mammary gland, and axillary nodes. (Poirier and Cun^o.) 

from the arm. They can often be pared off the vessels with ease, but sometimes 
are so firmly attached that the vessels are injured in their removal. 

The anterior or thoracic set accompany the long thoracic artery along the lower 
border of the pectoral muscles. They are not so numerous as the humeral set, 
perhaps four or five in number, and drain the anterior upper half of the chest above 
the umbilicus, including the mammary gland (Fig. 275). 

The posterior or scapular set accompany the subscapular artery along the pos- 
terior portion of the axilla. They are about as numerous as the anterior set and 
drain the upper posterior portion of the chest, the scapula and lower portion of the neck. 

The lymphatics of the middle and lower portion of the back as low down as the 
umbilicus (3 to 4 cm. above the iliac crest) also drain into the axilla. 

These lymphatic nodes communicate with one another, so that it does not of 
necessity follow that if the part ordinarily drained by a certain set is affected the 
nearest nodes will be involved. It usually is so, but not always. The infection may 
pass by or through one set of nodes and involve a neighboring communicating set. 
It happens in carcinoma of the breast that sometimes the posterior or scapular set are 



264 



APPLIED ANATOMY. 



involved and the anterior or thoracic set escape. This has already been alluded to 
in the section on the mammary gland (see page 184). These three sets drain into 
the subclavian nodes and then empty into the subclavian vein near its junction with 
the jugular. 

Abscess of the Axilla. — Pus forms in the axillary region from ordinary pyo- 
genic organisms which may or may not be associated with specific organisms like 
the tubercle bacillus. Abscesses may be either superficial or deep. 

The skm of the axilla is thin, loose, and abundantly supplied with sebaceous 
glands connected with the hair-follicles and sweat-glands. These glands are in the 
deeper layer of the skin and are superficial to the axillary fascia, hence abscesses 
originating from them tend to break externally; usually they do not become large 
nor extend deep into the axilla. 

Abscesses originating from the lymphatics, on the contrary, may be either deep in 
the axilla along the axillary, pectoral, or subscapular vessels, or they may be in the 
axillary fat and tend to point toward the skin. If the lymphatics along the axillary 
vessels are the point of origin, the abscess may follow them down under the deep 
fascia to the elbow. If the nodes high up are involved, the abscess may work up 
under the clavicle into the neck. If, however, the nodes near the apex of the axilla 




Fig. 276. — Subpectoral abscess. 

form the starting-point then the abscess bulges through the cribriform portion of the 
axillary fascia (between the " Armbogen " and " Achselbogen " ) into the axilla 
and tends to discharge through the skin. Abscesses originating in the pectoral 
group of lymphatics point at the lower margin of the anterior axillary fold. The 
attachment of the serratus anterior to the side of the chest prevents them from work- 
ing towards the back. 

Abscesses involving the subclavian nodes may cause a siibpedoi'al abscess (Fig. 
276). The pus collects superficial to the costocoracoid membrane and clavipectoral 
fascia and pushes the pectoralis major muscle outward, forming a large rounded 
prominence below the inner half of the clavicle. The pus cannot extend upward or 
toward the median line on account of the attachment of the pectoralis major muscle. 
It can burrow through the intercostal spaces and involve the pleural cavity, or break 
through the fibres of the pectoralis major anteriorly or between the pectoralis major 
and deltoid, or, as is most commonly the case, work its way under the pectoralis 
major muscle, over the pectoralis minor, until it reaches the border of the pectoralis 
major at the anterior fold of the axilla. 

In emptying these abscesses an incision is to be made along the anterior axillary 
fold and a tube introduced beneath the pectoralis major. 

Incision for Axillary Abscess. — In opening an axillary abscess one should bear in 
mind that the important veins and nerves accompany the arteries and that the arteries 
lie in three places, viz. , externally along the humerus, anteriorly along the edge of the 
pectoral muscles, and posteriorly along the edge of the scapula ; therefore these three 
localities are to be avoided and an incision made in the middle of the axilla and short 
enough not to endanger the brachial vessels on the outside or the long thoracic or 
subscapular on the inside near the chest-wall. 

The incision may divide the skin and if desired the deeper structures can be 
parted by introducing a closed haemostatic forceps and separating its jaws. 



THE AXILLA. 265 

Axillary abscesses, if of slow formation and unopened, tend to burrow and follow 
the vessels upward beneath the clavicle and appear in the supraclavicular space beneath 
the deep cervical fascia, and they may even enter the superior mediastinum. They 
may also descend the arm under the fascia covering the coracobrachialis muscle. 

Axillary Tumors. — Tumors of the axilla are almost always due to involvement 
of the lymph-nodes. They may be either benign and inflammatory in character, form- 
ing the ordinary axillary adenitis, or tuberculous, or they may be malignant. As 
they are due to disease of the lymph-nodes, the parts which the glands drain should 
be searched for the starting-point of the affection. Aneurism or abscess may be 
mistaken for a new growth and an inflamed aneurism may readily be thought to be 
an abscess. 

The excision of axillary tumors is difficult. If the tumor is of an inflammatory 
origin it may be closely adherent to the veins or arteries or nerves, and the same con- 
dition may exist in malignant cases. 

The blood supply of the axilla is so free that nothing is to be gained by saving 
small vessels, therefore in paring a tumor off the axillary vessels the various small 
branches are ligated and divided and the main vessels left bare. This applies to the 
veins as well as the arteries. 

The subscapular artery is so large that it is often allowed to remain. When 
working in the posterior portion of the axilla it is to be remembered that the pos- 
terior circumflex artery is opposite the surgical neck of the humerus, above the 
tendon of the latissimus dorsi muscle, and that the subscapular artery is on the 
opposite side of the axillary artery a little higher up. The large subscapular vein 
will bleed profusely if wounded and it should be looked for at the axillary border of 
the scapula below the subscapularis muscle. 

Wounds of the axillary vein are particularly dangerous on account of the admis- 
sion of air. The attachment of the vein to the under side of the pectoralis minor and 
costocoracoid membrane keeps it from collapsing; hence the danger. 

Nerves of the Axilla. — The brachial plexus is above the first portion of the 
axillary artery. In the second portion one cord is to the inner side, one to the 
outer, and one behind. In the third portion the median nerve is anterior and a little 
to the outer side of the artery, being formed by two roots, one from the inner and 
the other from the outer cord of the brachial plexus. 

The musculocutaneous nerve is to the outer side of the artery, leaving the outer 
cord to enter the coracobrachialis muscle. The ulnar, internal cutayieous {cutaneus 
antebrachii medialis), and lesser internal cutaneous {czitaneus brachii medialis) come 
from the inner cord and lie to the inner side of the artery. From the posterior cord 
come the axillary {circumflex^ and radial (^musculo spiral^ nerves. On the inner wall 
of the axilla behind the long thoracic artery is the N. thoracalis longus (long thoracic, 
or external respiratory nerve of Bell); it is a motor nerve and supplies the serratus 
anterior (magnus) muscle, hence it is not to be injured in clearing out the axilla. 

Still farther posteriorly, accompanying the subscapular artery, is the thoraco- 
dorsalis or long subscapular nerve. It also is a motor nerve supplying the latissimus 
dorsi muscle; therefore it is to be spared. 

Crossing the axilla from the second intercostal space to anastomose with the 
cutaneus brachii medialis nerve is the intercostobrachial {humeral^ nerve. It is a 
nerve of sensation and need not be spared. Sometimes another branch from the 
third intercostal nerve also crosses the axilla; it is also sensory and can be cut away. 

As the axillary {circumflex) nerve normally winds around the surgical neck 
of the humerus, when luxation occurs it is stretched over the head and paralysis of 
the deltoid may ensue. 

The various nerves of the brachial plexus are often injured by pressure resulting 
from the use of crutches ("crutch palsy"). It is liable to affect any or several of 
the nerves, the radial (musculospiral) probably the most frequently. Neuritis is 
common and, as in injuries, the nerves affected are recognized by the motor or 
sensory symptoms produced. 



266 



APPLIED ANATOMY. 



THE ARM. 

The arm — or upper arm — is formed by a single bone surrounded by muscles, 
which, with the exception of the biceps, are attached to it. The main vessels and 
most of the important nerves run down its inner side. It receives from the trunk the 
insertions of the muscles which move it, and gives origin to the muscles which move 



Anatomical nee 



Supraspinatus. 

Greater tuberosity. 
Lesser tuberosity 

Bicipital groove 

Surgical neck 



Pectoralis major, 



Brachioradialis 



Extensor carpi 
radialis longior 



Radial fossa 



Teres major 




— \— Rubscapularis 



Anatomical 
Latissi- neck 

mus dorsi 



Capitellu 



Trochlea 




Olecranon 
Pronator fossa 

radii teres 
Common flexor 
tendons 

Flexor carpi 

ulnaris and 

other flexors 



Supraspinatus 
Infraspinatus 

Greater tuberosity 
Teres minor 



Deltoid 



Brachialis anticus 
Musculospiral 
(radial) groove 



Anconeus 



Trochlea 



Fig. 277. — Anterior surface of humerus, showing 
attachment of muscles. 



Fig. 278. — Posterior surface of humerus, showing 
attachment of muscles. 



the forearm. It is more subject to injury than to disease; infection, caries, and 
rickets may attack the bone and rarely new growths may occur, but its common 
affections are wounds involving the muscles, blood-vessels, or nerves, and fractures 
of the bone. Severe injuries occasionally necessitate amputation. 



THE ARM. 267 

THE HUMERUS. 

The humerus is a long bone with a large medullary cavity. Its shaft is com- 
posed of compact tissue and its ends of cancellous tissue. In shape it is like the 
letter /, that is, convex anteriorly above and concave anteriorly below. At the mid- 
dle of the bone on its external surface is the rough deltoid eminence for the insertion 
of the deltoid muscle. 

Anterior Surface. — Separating the tuberosities above and running down the 
anterior surface is the bicipital groove. Its external lip receives the insertion of the 
pectoralis major muscle, its inner lip and floor those of the latissimus dorsi above and 
the teres major below. On its inner side at and a little below its middle, is the 
insertion of the coracobrachialis muscle. On the anterior surface from the deltoid 



Coracoid process 



Pectoralis major 




Pectoralis minor 

Subscapularis 

Ti .. y^ / "^^^^^^^^^^^^^K*^ ^.-^ — Teres major 

Pectoralis major/ ^^^^^^^^^^H^^--^'^ — 

Long head of biceps,^,--' [J^ 

^ . ^ ^ . , ^^^ ^___ Latissimus dorsi 

Short head of biceps 

Coracobrachialis, 



Inner head of triceps 



Fig. 279. — Muscles of the anterior and internal aspects of the region of the shoulder. 

eminence to the elbow-joint is the origin of the brachialis anticus; it has two heads, 
which embrace the insertion of the deltoid, one being in front and the other behind 
it (Fig. 277). 

Posterior Surface. — On the posterior surface, running obliquely across the 
bone downward and outward, below the insertion of the deltoid, is a shallow groove, 
called the inusculospiral groove {stdciis radialis). It holds the musculospiral 
{radial) nerve and the superior profunda artery. Above the groove and to its 
outer side is the origin of the outer head of the triceps extensor muscle and the 
insertion of the deltoid. To its inner side, below, is the origin of the inner head 
of the triceps. Therefore the groove separates the inner head of the triceps muscle 
from the outer (Fig. 278). 

MUSCLES OF THE ARM. 

In order to operate intelligently it is necessary to know the muscles and inter- 
spaces, for the latter carry important structures. The arm possesses four sets of 
muscles. One, an external set, abducts it, the deltoid ; another, or internal set, ad- 
ducts it (and rotates it inward), the pectoraliz major , teres tnajor, latissimus dorsi, 
and coracobrachialis ; another, anterior set, flexes the forearm, the biceps, and the 
brachialis anticus; and the last, or posterior set, extends the forearm, the triceps, with, 
sometimes, the subajiconeus beneath it. 



268 



APPLIED ANATOMY. 



The External, or Abductor Set. 

This comprises only one muscle, the deltoid; the supraspinatus belongs to the 
shoulder region. 

The deltoid forms the large rounded prominence of the shoulder. At its 
insertion the bone is nearest the surface and can be most readily felt. The posterior 
edge can be plainly seen when contracted running upward and inward and crossing 



Acromion process 

Coracoid process 

Deltoid 

Long head of biceps 

Short head of biceps 
Pectoralis major 

Biceps (cut edge) 



Brachialis anticus. 



Outer condyle 
Capitellum 



Insertion of 
biceps tendon 



Radius 




Subscapularis 



Teres major 
Latissimus dorsi 



Coronoid process of ulna 



Fig. 280. — Anterior view of muscles of the arm. 

the posterior fold of the axilla at right angles. Its anterior edge blends more or 
less completely with the pectoralis major (Fig. 279). 

The Internal Set. 
The internal set includes the coracobrachialis, with the short head of the biceps, 
and the pectoralis major, teres major, and latissimus dorsi. 



THE ARM. 269 

The coracobrachialis arises from the coracoid process and tendon of the short 
head of the biceps and inserts on the inner surface of the humerus for a distance 5 to 
7.5 cm. (2 to 3 in.) opposite the insertion of the deltoid, but extending a htde lower. 
In its course from the coracoid process, in its lower part, it is subcutaneous and pro- 
duces a distinct muscular prominence along the anterior border of the axilla. It 
occupies about one-third of the width of the axilla and is a guide to the brachial 
artery. Below the edge of the anterior axillary fold it dips down to insert into the 
bone' and is covered by the biceps muscle. The inner edge of the coracobrachialis 
is continuous with the inner edge of the biceps. When it contracts it adducts the 
humerus and brings it forward. 

The pectoralis major, forming the anterior axillary fold, inserts into the 
external lip of the bicipital groove from the greater tuberosity above to the insertion 
of the deltoid below. The tendon is twisted on itself so that the lowest fibres at its 
origin are inserted the highest, and the highest in origin are the lowest at their 
insertion. 

The latissimus dorsi and teres major form the posterior axillary fold and 
their manner of insertion resembles that of the pectoralis major. The tendon of the 




Fig. 28 1 . — Rupture of the tendon of the long head of the biceps muscle, producing a swelling 
comparatively low down. 

latissimus dorsi inserts into the bottom of the bicipital groove higher up than the 
teres major. Hence near the humerus the lower edge of the posterior axillary fold 
is formed by the teres major and its lower border marks the lower limit of the axillary 
and the beginning of the brachial artery. 

As the pectoralis major, latissimus dorsi, and teres minor muscles insert on the 
anterior surface of the humerus, they tend to rotate it inward as well as to adduct it. 

The Anterior Set. 

The biceps and brachialis anticus form the muscular mass on the anterior surface 
of the arm. 

The biceps has no attachment to the humerus. It spans the bone and is 
attached to the scapula above and to the radius and deep fascia of the forearm below. 
In the lower half of the arm it lies on the brachialis anticus. The long head runs 
up in the bicipital groove, and is covered by the tendon of the pectoralis major up to 
the tuberosities, above that by the transverse humeral ligament up to the capsule, 
which it perforates, and, crossing over the head of the humerus, is attached to the 
upper edge of the rim of the glenoid cavity (Fig. 280). 

The bicipital branch of the anterior circumflex artery accompanies the tendon 
in the bicipital groove. This tendon is comparatively rarely luxated, because it is 



270 



APPLIED ANATOMY. 



firmly held in place by the transverse humeral ligament. Pus, in finding- an exit 
from, the joint, follows the long tendon of the biceps and passes under the transverse 
humeral ligament, then beneath the tendon of the pectoralis major to appear on the 
anterior aspect of the arm at its lower border. Luxation of the tendon outwardly 
would be opposed by the insertion of the pectoralis major, therefore it is only dis- 
placed inwardly. Rupture of the long tendon may occur from violent muscular con- 
traction; or, in rheumatoid arthritis of the shoulder, the tendon may become partly 
dissolved and break. When this occurs the belly of the muscle contracts and forms 
a large protuberance on the front of the arm (Fig. 281). 

The short head of the biceps fuses with the coracobrachialis muscle, to be 
attached with it to the coracoid process on its outer portion. The pectoralis minor is 

the third muscle attached to this process. 
The biceps forms the large muscular 
swell on the front of the arm between 
the anterior fold of the axilla and elbow. 
At its lower end the biceps inserts by a 
strong tendon into the posterior border 
of the bicipital tubercle of the radius. 
An example of its rupture is shown in 
Fig. 282. Between it and the bone is 
a bursa, which does not communicate 
with the elbow-joint. The bicipital fas- 
cia is given of? from the tendon and 
passes downward and inward to blend 
with the deep fascia covering the flexor 
group of muscles. The biceps not only 
flexes the radius on the arm but also acts 
as a powerful supinator. 

The brachialis anticus covers 
the lower three-fifths of the humerus 
and begins with two slips, one on each 
side of the insertion of the deltoid ten- 
don. It inserts into the inner and lower 
part of the anterior surface of the coro- 
noid process of the ulna. As the articu- 
lation of the ulna and trochlear surface 
of the humerus is a pure hinge-joint the 
muscle acts solely as a flexor. 

The Posterior or Extensor Set. 
The posterior or extensor set in- 

PiG. 282. — Rupture of the lower tendon of the biceps. i j ...i ... • j i.i. u „ 

Contraction of the muscle produces a swelling abnormally CludCS the triCCpS and the SubanCOneOUS, 

high up on the arm. (From a photograph.) when present as a distinct muscle. 

The Triceps Muscle. — The mus- 
cular mass on the posterior surface of the arm is formed solely by the triceps muscle. 
It arises by three heads and inserts by a single tendon into the olecranon process of 
the ulna. Its three heads are the long, external, and internal. The long head arises 
from the lower edge of the glenoid cavity and the scapular border below it for 2.5 
cm. (i in.). It blends with the capsule of the joint and tends to strengthen it at 
this point. When the arm is abducted, this tendon is closely applied to the capsule 
and head of the humerus, and when the head escapes in luxation, it slips out anterior 
to the tendon. The external head arises from the humerus above the musculospiral 
groove and from the external intermuscular septum; the internal head arises from 
the humerus below the musculospiral groove and from the internal and the lower 
part of the external intermuscular septum (Fig. 283). 

At its lower end the triceps inserts into the olecranon process, the upper third 
of the ulna, and the deep fascia of the back of the forearm. The expansion of fascia 
from the olecranon on the inner side is thin and insignificant, but that on the outer 
side, on the contrary, is thick and strong, and when fracture of the bone occurs is an 
important factor in preventing separation of the fragments. 




THE ARM. 



271 



Outer head 
of triceps 



THE INTERMUSCULAR SEPTA. 

The deep fascia of the arm completely encircles it, like a tube. It is continuous 
above with the fascia co\'ering the deltoid, pectoralis major and teres major muscles, 
and axillary fascia. Below, it is continuous with the fascia of the forearm and is 
attached to the olecranon and internal and external condyles. 

On each side of the lower half of the humerus, extending from the condyles and 
the bone above outward to the deep fascia, are two fibrous partitions. They are 
the internal and external internniscular 
septa. The space in front of them is filled 
by the flexors, the biceps, and brachialis 
anticus, and the space behind contains 
the triceps extensor. The external sep- 
tum begins at the external condyle and 
extends above to the tendon of the del- 
toid, with which it blends. The internal 
septum begins below at the internal con- 
dyle and extends above to the coraco- 
brachialis. The radial (musculospiral) 
nerve and anterior terminal branch of 
the (superior) profunda artery, as they 
wind around the humerus below the in- 
sertion of the deltoid, pierce the external 
septum. The internal septum is pierced 
high up by the ulnar nerve and superior 
ulnar collateral (inferior profunda) artery 
as they emerge at about the level of the 
lower portion of the insertion of the 
coracobrachialis to pass down behind 
the internal condyle. 

These intermuscular septa are of 
importance in operative procedures be- 
cause they indicate the limits of the mus- 
cles and position of nerves and vessels. 

SURFACE ANATOMY. 

Inasmuch as the movements of the 
elbow-joint are anteroposterior only and 
not lateral, the muscles are principally 

on the front and back and not on the "X WSi^km Anconeus 

sides. Hence on looking at an arm 
a rounded mass is seen anteriorly and 
posteriorly, and separating them on the 
sides can be seen in a spare, muscular 
individual, distinct furrows called the 
internal and external bicipital furrows. 
If these furrows are obscured by fat, 
one can still feel that the bone is nearer 
the surface at these points than else- 
where. The anterior muscle mass is 
formed by the biceps and brachialis 

anticus muscles, the posterior mass by the triceps. The bone is most readily 
felt at the insertion of the deltoid at the middle of the outer side of the arm. 
From this point directly down to the external condyle passes the external inter- 
muscular septum and external bicipital furrow. Winding around from the poste- 
rior edge of the insertion of the deltoid is the radial {iniisculospirai) 7ierve and 
{supej'ior) profunda artery. They pierce the external intermuscular septum and 
pass downward in the groove formed by the brachioradialis (supinator longus) and 
extensor muscles on the outside and the brachialis anticus on the inside. On the 
inner side of the arm the bicipital furrow, between the biceps in front and the triceps 




Inner head 
of triceps' 



Fig. 283. — Triceps and anconeus muscles. 



272 



APPLIED ANATOMY. 



behind, is quite evident and marks the internal intermuscular septum, which extends 
to the medial (internal) condyle. In front of it lie the brachial artery and veins, 
and median and ?nedial antebrachial {internal) cutaneous nerve. At the upper 
portion of the inside of the arm can be seen the swell formed by the coracobrachialis 
muscle. The inner or posterior border of the coracobrachialis is continuous with 
the inner border of the biceps, and the brachial artery follows them. The coraco- 
brachialis muscle ends just below the level of the insertion of the deltoid, and, of 
course, can neither be seen nor felt below that point. It is here that the ulnar nerve 
leaves the artery to pierce the internal intermuscular septum in company with the 
superior 2ilnar collateral {inferior profunda) artery to reach the groove behind the 
internal condyle. The brachial artery is covered only by the skin and superficial and 
deep fascia, and can be felt pulsating along the inner edge of the biceps muscle and 
tendon; it can be compressed against the bone by pressure directed outwardly 
above and inclining more posteriorly as the artery progresses down toward the bend 
of the elbow. It is on the inner side of the arm in the upper two-thirds, and is more 
anterior in the lower one- third (Fig. 284). 

The cephalic vein runs up the external bicipital furrow and the basilic up the 
internal. At the junction of the middle and lower thirds of the arm the basilic 
pierces the deep fascia and from that point runs up beneath it and joins with the 
internal vena conies opposite the lower border of the teres major or subscapularis. 

THE BRACHIAL ARTERY. 

The arm being abducted, the course of the brachial artery is indicated by a 
line drawn from the inner edge of the coracobrachialis muscle, at the junction of 
the anterior and middle thirds of the axilla, above, to a point just inside the tendon 
of the biceps at the bend of the elbow, below, midway between the two condyles 
of the humerus. This lies in the internal bicipital furrow along the inner edge of 
the biceps muscle. The artery is superficial in its entire course. It is accom- 
panied by two small venae comites, which closely embrace it. The basilic vein 
runs along its inner side. The median nerve lies on the artery to its outer side 
above, then directly on it and a little to its inner side at the middle, and passes 
to its inner side at the bend of the elbow. The medial antebrachial (internal) 
cutaneous nerve, much smaller than the median, passes down along the inner side 
of the artery between it and the basilic vein to pierce the fascia about the middle of 
the arm (Fig. 285). 

The ulnar 7ierve lies to the inner side of the artery above and is posterior to the 
basilic vein. About opposite the insertion of the coracobrachialis it diverges from 
the artery to pierce the internal intermuscular septum. 



Older Side 
Median nerve, above 
Coracobrachialis 
Biceps 
Vena comes 



Relations of the Brachial Artery 

In Front. 
Skin and fascia 

Overlapped by coracobrachialis and biceps 
Median basilic vein 
Bicipital fascia 
Median nerve 

Intter Side 
Medial antebrachial (int.) 
Brachial cutaneous and 

Artery ulnar nerves 

Median nerve below 
Basilic vein 
Vena comes 
Behind 
Triceps (long and inner heads) 
Radial (musculospiral) nerve 
(Sup.) profunda artery 
Coracobrachialis muscle 
Brachialis anticus muscle 



THE ARM. 



273 



Branches of the Brachial Artery, — The branches of the brachial artery are 
the profunda (superior), the superior ulnar collateral (inferior profunda), the nutrient, 
muscular, and inferior ulnar collateral (anastomotica magna). 



Deltoid 



Supinators and extensors 




Pronators and flexors 

Internal bicipital furrow 

Triceps, long and inner heads 

Brachial artery 

Coracobrachialis muscle 
Fig. 284. — Surface anatomy of the arm. 

Not infrequently the brachial artery instead of dividing into the radial and ulnar 
opposite the neck of the radius divides higher up. This is called a high division and 
is seen most often in the upper third of the arm. The two vessels may follow the 



Musculocutaneous nerve 

Brachial artery 
Coracobrachialis -' 
Median nerve 

Biceps 




Latissimus dorsi 



Brachialis anticus 



Superior profunda artery 
Musculospiral nerve 
Inner head of triceps 
Ulnar nerve 

Inferior profunda artery 



Anastomotica magna arterj' 

Basilic vein 

Fig. 285. — Dissection of the arm, viewed from the inner side. 



usual course in the arm, or the radial may run under the biceps tendon, instead of 
over it, and the ulnar may accompany the median nerve in front of the medial con- 
dyle or the ulnar nerve behind it. 



274 



APPLIED ANATOMY. 



The prof mida is given off just below the lower edge of the posterior fold of the 
axilla (teres major). It accompanies the radial (musculospiral) nerve around the 
arm to its outer side; it sends one branch, the radial collateral, to the front of the 



Median nerve 
Biceps muscle / 




Ulnar nerve 



Brachial artery 



. Superior profunda (A. profunda 
brachii) 

• Brachial artery 

. Inferior profunda (coUateralis 
ulnaris superior) 



Anastomotica magna (collate- 
"ralis ulnaris inferior) 



Fig. 286. — Ligation of the brachial artery in the middle of the arm showing the median nerve lying on the artery 

and the ulnar nerve to its inner side. 

elbow and the middle collateral behind it. The superior ulnar coIlate7-al artery 
(inferior profunda) comes off about opposite the insertion of the coracobrachialis 

muscle. It is much smaller than the pro- 
funda and with the ulnar nerve pierces the 
internal intermuscular septum. The nutri- 
ent artery comes off close to the origin of 
the superior ulnar collateral (inferior pro- 
funda) or is a branch of it. It passes down- 
ward in the bone in a direction toward the 
elbow-joint. The inferior ulnar collateral 
(anastomotica magna) is given off 5 cm. 
(2 in.) above the elbow and passes inward 
over the brachialis anticus to divide into 
two branches, one going down in front and 
the other behind the elbow. 

Ligation of the Brachial Artery. 
— In ligating the brachial artery. Heath 
strongly advises that the arm be held by an 
assistant in an abducted position with the 
hand supine,and not allowed to rest on any- 
thing. The object of this is to avoid hav- 
ing the artery overlapped by the triceps be- 
ing pushed up and thus becoming obscured. 
The incision is to be made in the line 
from the inner edge of the coracobrachialis 
to a point midway between the tips of the 
condyles. The deep fascia is to be opened 
and the inner edge of the biceps muscle 
is to be sought for, recognized, and held 
outward. The pulsation of the artery may 
indicate its position in the living; if not, it 
is to be sought for to the inner side of the 
edge of the biceps. The median nerve is 
not to be mistaken for it. It will lie either 
over its middle or to its inner side if low down and to its outer side if high up (Fig. 286). 
The ulnar nerve lies on the inner side of the artery as far as the middle of the 



-Radial recurrent 
-Ulnar recurrent 



-Interosseous recurrent 
- Posterior interosseous 



— Anterior interosseous 
"Radial artery 
-Ulnar artery 



'A 



Fig. 287. — Collateral circulation after ligation of the 
brachial artery at the bend of the elbow. 



THE ARM. 275 

arm, it then leaves the artery. Below the middle, if the search is made too far 
posteriorly, the ulnar nerve and basilic vein will be encountered. The ulnar nerve 
should not be seen, the basilic vein and median nerve — and above the middle of the 
arm the medial antebrachial (internal) cutaneous nerve — are to be displaced to the 
inner side. 

The needle is to be passed from within outward. Care must be taken not to 
mistake a large superior or inferior profunda for the main trunk. A high division 
of the brachial may give two vessels of approximately equal size. Of course, in such 
a case both must be ligated. 

Collateral Circulation. — If the ligature is placed above the profunda (superior) 
branch, the anterior and posterior circumflex will anastomose with the profunda 
(superior) and superior ulnar collateral (inferior profunda) below. If the ligature is 
placed between the profunda and superior ulnar collateral arteries, the profunda 
(superior) will anastomose below with the radial recurrent and posterior interosseous 
recurrent on the outer side and will also communicate with the inferior ulnar 
collateral (anastomotica magna) and superior ulnar collateral (inferior profunda) 
on the inside (Fig. 287). If below the superior ulnar collateral (inferior profunda) 
then the profunda (superior) would anastomose with the radial and posterior inter- 
osseous recurrents on the outside, and the superior ulnar collateral (inferior profunda) 
with the inferior ulnar collateral (anastomotica magna) and the anterior and posterior 
ulnar recurrents. 

AMPUTATION OF THE ARM. 

In amputation one has to deal with a part of the body that is approximately 
cylindrical in shape and that contains only a single bone entirely surrounded by 
soft parts. The circular method is more applicable to amputation of the arm below 
the insertion of the deltoid than to any other part of the body, but nevertheless in 
some cases, particularly in muscular arms, difficulty may be experienced in turning 
back the cuff. In such cases the cuf5 is slit by the surgeon and the operation 
becomes one of square skin flaps. For this reason flap amputations are usually to 
be preferred. 

The arm may be amputated at any place, high up or low down. Artificial 
appliances for the upper extremity are comparatively useless; hence the height of 
division of the bone is determined by the injury. 

As it is desirable to retain the head of the bone and tuberosities, if pos- 
sible, in order to preserve the shape of the shoulder and retain the attachment 
of the muscles, amputation may be done through the surgical neck. This is just 
below the epiphyseal line. In performing a flap amputation the soft parts should 
cover or cap the bone like a hemisphere: therefore the total length of the flaps should 
be equal to one-half the circumference of a sphere whose diameter is the diameter of 
the limb at the point of section of the bone. If the diameter of the limb is 4 inches, 
then the total length of the flaps should be approximately 6 inches. If the flaps 
were of equal length then each would be 3 inches long. If there was only one flap, 
it would be 6 inches long. 

It is an axiom in surgery that in flap amputations the artery should be contained 
in the shorter flap. The operator should accurately know the course of the artery 
and avoid making his flaps in such a manner as to bring the vessel in the angle of the 
wound. Otherwise the artery is liable to be split. In a high amputation the 
external flap may be long and the internal short. In the middle of the arm antero- 
posterior flaps are preferred and the artery is included in the posterior flap. If the 
amputation is in the lower third and the flaps are anteroposterior, then the artery of 
necessity is in the anterior flap. 

Above the middle of the arm the deltoid, coracobrachialis, and biceps muscles 
are free and therefore retract markedly when cut. In the middle the biceps only is 
free and the same is the case in the lower third. The triceps and brachialis anticus 
are attached to the bone and therefore retract but little when cut. Surgeons have 
called attention to the necessity of being careful to see that the radial (musculospiral) 
nerve is properly divided, otherwise it may be torn by the saw. The groove in which 



276 



APPLIED ANATOMY. 



it lies may be unusually deep and necessitate a special effort to divide it. On the face 
of the stump the artery is to be looked for to the inner side of the bone in the upper 
two-thirds of the arm and anteriorly in the lower third. Lying on it will be the 
median nerve and to its inner side the ulnar nerve. At the level of the insertion of 
the deltoid the radial (musculospiral) nerve, accompanied by the (superior) profunda 
artery, will be posterior or toward the outer side. The superior ulnar collateral (in- 
ferior profunda) artery is given off at the level of the insertion of the coracobrachialis 
muscle, which is about opposite the insertion of the deltoid. It accompanies the ulnar 
nerve. A nerve may be seen lying between the biceps and brachialis anticus. It is the 
musculocutaneous which becomes superficial just above the bend of the elbow (Fig. 288) . 



Median nerve 

Brachial artery 
Internal cutaneous nerve ^ 



Ulnar nerve and inferior 
profunda artery 



Coraco-brachialis 

Musculospiral nerve and 
superior profunda artery 




Biceps 
Musculocutaneous nerve 



Brachialis anticus 



Deltoid 



Triceps 



Triceps 



Fig. 288. — Amputation just above the middle of the arm. 

Five cm. (2in. ) above the elbow the inferior ulnar collateral (anastomotica 
magna) artery may be expected to be encountered passing down and in over the 
brachialis anticus muscle. 



FRACTURES OF THE HUMERUS. 



Fractures of the Shaft of the Humerus. — There seems to be but little doubt 
that in many cases the character of displacement of the fragments in fracture of the 
shaft of the humerus is due to the mode of injury and not to muscular action. This 
being so accounts for there being less uniformity in these fractures than in those 
higher up, which have already been considered. There are some cases, however, in 
which muscular action does play a part and the possible influence of the muscles 
should be understood. 

The line of fracture is usually more or less oblique, in rare cases nearly trans- 
verse, but the displacement is often not marked. Notwithstanding this latter fact, 
non-union of fracture of the shaft of the humerus is one of the most frequent of any 
in the body. 

Muscular action shows its influence most markedly in producing displacements 
in three directions, viz. , in towards the body, out away from the body, and directly 
anteriorly. 



THE ARM. 



277 



There are two main points where fracture occurs; immediately above the inser- 
tion of the deltoid and below it. 

Frachire above the Insertion of the Deltoid. — The bone may be fractured imme- 
diately above the deltoid insertion. In this case the powerful axillary fold muscles, 
pectoralis major, teres major, and latissimus dorsi, being attached to the upper frag- 
ment, tend to draw it toward the body, while the deltoid tends to draw the lower 
fragment out. The influence of the other muscles, biceps, coracobrachialis, and triceps, 
would be to increase the overlapping (Fig. 289). 

Fracture belozv the Deltoid Insertion. — This is the more common site of fracture. 
The line of fracture is most apt to be from above downward and outward. The 
upper fragment is displaced anteriorly by the coracobrachialis and anterior portion 



Pectoralis major 



Latissimus dorsi 



Deltoid 




Teres major 



Fig. 289. — Fracture of the shaft of the humerus just above the insertion of the deltoid and below the inser- 
tion of the axillary fold mviscles. The lower fragment is seen to be drawn outward by the deltoid; the upper frag- 
ment is seen to be drawn inward by the pectoralis major, latissimus dorsi, and teres major. 



of the deltoid and is drawn outward by the deltoid aided by the supraspinatus. To 
relax the deltoid the arm is sometimes dressed in an abducted position (Fig. 290). 

Non-Union. — The humerus has muscles attached to it almost throughout its 
entire length, and w^hen the sharp ends of the fragments are displaced they probably 
become fixed in the surrounding muscle, and proper apposition of the fragments is 
prevented, hence non-union. Hamilton believed that lack of proper fixation was also 
a prominent cause. 

The Radial (Musculospiral) Nerve. — In fracture of the shaft of the 
humerus, paralysis of the extensors due to injury of the radial nerve is compara- 
tively common. It also occurs from pressure due to the use of crutches, to sleep- 
ing on the arm, etc. The other nerves are too far removed from the bone to 



278 



APPLIED ANATOMY. 



be injured, but the radial (musculospiral) lies on the bone in the radial (musculo- 
spiral) groove in approximately the middle third of the bone. It comes into contact 
with the bone posteriorly above the insertion of the deltoid and leaves the bone on 
its outer anterior surface to pass between the brachialis anticus and brachioradialis 
(supinator longus) muscles. Paralysis may be caused (i) by direct injury to the 
nerve at the time the fracture is received. (2) By subsequent changes in the nerve 
due to its being stretched over the sharp edge of a fragment. (3) By being included in 
callus. The last is probably much more rarely the case than the two former (Fig. 291). 
Paralysis should be examined for early in the course of treatment. Too often it 
is detected only after the splints have been removed, and then it is apt to be ascribed 
to improper treatment or to misapplied pressure. The symptoms of involvement of 



Deltoid 




Infraspinatus 



Teres minor 



Site of fracture 



Teres major 



Latissimus dorsi 



Long head of triceps 



External head of triceps 




Fig. 290. — Posterior view of a fracture of the shaft of the humerus just below the insertion of the deltoid, 
showing the influence of that muscle in producing abduction of the upper fragment. 

the musculospiral nerve are wrist-drop and diminution of the power of supination, 
also some sensory changes in the dorsum of the hand and forearm. 

This nerve is frequently paralyzed from pressure in cases in which there is no 
fracture, as from sleeping on the arm, the use of crutches, and also in certain sys- 
temic affections, such as lead poisoning. It suppHes the triceps, part of the brachialis 
anticus, brachioradialis (supinator- longus), and extensor carpi radialis longior 
muscles in the arm, and then proceeds to the forearm. The branch to the triceps is 
given off before the nerve enters the musculospiral groove, hence is not often injured, 
and loss of extension of the forearm is not often present; even paralysis of the other 
muscles mentioned is not common, the forearm muscles being mostly affected. The 
branch to the inner head of the triceps also supplies the anconeus. 



THE ARM. 



279 



OPERATIONS ON THE ARM. 

Caries or necrosis of the humerus may necessitate operative interference at almost 
any part of the arm. The same may be said of wounds. In operative procedures 
it is sometimes desirable to avoid important structures and at others to find them. 



Deltoid 



Brachialis anticus 




Long head of triceps 



Outer head of triceps 
Radial (musculospiral) nerve 

Superior profunda artery 

Brachioradialis 

Extensor carpi radialis longior 

Extensor muscles of forearm 
External condyle 



Fig. 291. — The radial (muscolospiral) nerve and outer side of arm. 

The important structures run lengthwise, hence transxerse incisions are not to be 
used. Most of the large vessels and nerves pass down the inner side of the arm, 
hence this region is usually avoided. The bone can readily be reached by an incision 
downward from the insertion of the deltoid, but no operation is to be done in this 
region without a thorough familiarity with the course of the musculospiral nerve. 



28o APPLIED ANATOMY. 

A line drawn on the posterior surface of the arm from behind and above the insertion 
of the deltoid to the groove on the anterior surface between the brachialis anticus and 
brachioradialis (supinator longus) just above and to the inner side of the external 
condyle will indicate its course. If exposed during an operation bleeding from the 
accompanying (superior) profunda artery may be expected. The median and ulnar 
nerves give off no branches in the upper arm. The median can be readily located 
by its relation to the artery. It lies to the outer and anterior side of the brachial 
artery above, then in front, and then to its inner side below. The ulnar nerve lies 
to the inner side of the artery and between it and the vein posteriorly. In the middle 
of the arm, it leaves it to pierce and pass beneath the internal intermuscular septum 
and thence behind the medial (internal) condyle. Operations involving it would 
be accompanied by bleeding from its companion the superior ulnar collateral artery 
(inferior profunda). 

In operations on the lower portion of the bone the position of the inferior ulnar 
collateral (anastomotica magna), 5 cm. (2 in.) above the elbow, should be borne in 
mind. It runs on the brachialis anticus muscle and towards the inner and not the 
outer side. Incisions on the outer side will encounter the cephalic vein in the external 
bicipital furrow. Incisions on the inner side will encounter the basilic vein ; at the 
junction of the lower and middle thirds of the arm it pierces the deep fascia. 

REGION OF THE ELBOW. 

The elbow is so named because at this point the arm is usually bent. A joint is 
here inserted which permits of flexion and extension ; when the arm is fully extended 
the "elbow" might be said to have disappeared. The lower end of the humerus 
forms the proximal portion of the joint and the upper ends of the ulna and radius form 
its distal portion. Ligaments join these bones together to form the joint, and the 
blood-vessels and nerves change in .character in this region as they pass from the arm 
to the forearm. ' l' * 

The bones are frequently subject to fractures which are of an exceedingly puz- 
zling and disabling character. The joint becomes luxated and the vessels and nerves 
are not infrequently injured. A thorough knowledge of the anatomy of the region 
is absolutely essential to the proper treatment of these affections. 

BONES OF THE ELBOW. 

Humerus. — The lower end of the humerus broadens laterally and is slightly 
concave on its anterior surface ; this causes the articular surfaces to look downward 
and forward and not backward. It carries two articular surfaces: one, the trochlea, for 
the ulna, and the other, the capitellum, for the radius. The trochlea, descending 
lower than thecapitellum, causes the line of the joint to incline downward and inward 
instead of being directly transverse, thus producing the " carrying angle" (Fig. 294). 
Extending from the edges of the articular surfaces outward, one on each side, are the 
condyles, medial {internal^ and lateral {extertial) . 

Chaussier gave the name epico?tdyle to the condyles. He called the medial 
condyle the epitrochlea and the lateral (external) condyle the epicondyle. Henle 
called the internal condyle the epicondylus medialis and the external condyle the 
epicondylus lateralis. The name epicondyle is now quite generally employed by both 
surgical and anatomical writers to designate the projecting extra-articular portion of 
the condyles, so that the terms are practically synonymous (Fig. 293). 

From the condyles two ridges run upward. The lateral {exteryial) supracon- 
dylar ridge is the more marked of the two and gives origin to the brachioradialis 
(supinator longus) and the extensor carpi radialis longior muscles, and passes 
posterior to the deltoid eminence to be continuous with the posterior lip of the 
radial (musculospiral) groove. The medial {internal^ supracondylar ridge is much 
less prominent than the lateral and soon blends with the shaft of the bone. Above 
the trochlea and capitellum anteriorly are two fossae, the coronoid and the radial, 
to receive the coronoid process and head of the radius when the arm is in complete 



REGION OF THE ELBOW. 



281 



flexion. On the posterior surface there is another depression, the olecranon fossa, to 
receive the olecranon process in extreme extension. The projecting- hook-Uke shape 
of the median condyle causes it to be more frequently fractured than the less promi- 
nent lateral condyle. The two condyles are readily felt directly beneath the skin and 
are the only points of the humerus that are really subcutaneous. 

Ulna. — The upper extremity of the ulna articulates above with the trochlea of 
the humerus and on its outer side with the radius. Its upper end is the olecranon 
process. The posterior portion of this process is called the tip of the olecranon and 
is continuous with the posterior surface of the ulna, which is subcutaneous. Immedi- 




FiG. 292. — .\nterior view of bones of right elbow. 



Fig. 293. — Posterior view of bones of elbow. 



ately in front of the olecranon is a large hollow, which receives the trochlea. It is 
called the greater sigmoid cavity. The anterior margin of the cavity is called the 
coro7ioid process. On the outer side of the coronoid process is a hollow called the 
lesser sigmoid cavity, which receives the head of the radius. Fracture of the bone 
frequently occurs through the narrow portion of the olecranon process into the greater 
sigmoid cavity. 

Radius. — The radius ends above in a fiat rounded head. The upper surface 
of this head articulates with the capitellum. The lateral surface articulates internally 
with the lesser sigmoid cavity of the ulna. The remainder of the circumference of 
the head is embraced by the orbicular ligament. Immediately below the head is the 
constricted neck and bicipital tuberosity. To the posterior half of this latter the 
tendon of the biceps is attached, but its anterior portion is smooth and provided with 
a bursa. The head of the radius is subcutaneous posteriorly, but the rest is too much 
covered by muscles to be readily palpated. 



2S2 



APPLIED ANATOMY. 



ELBOW-JOINT. 

By the term elbow-joint is meant the articulation between the humerus above 
and the ulna and upper surface of the radius below. The articulation between the 
upper end of the radius and the ulna forms the superior radio-ulnar articulation and 
does not belong to the elbow-joint proper. As has already been pointed out, the 
ulna articulates with the trochlea and the radius with the capitellum. 

The elbow-joint is a pure hinge-joint. The articulation between the trochlea 
and ulna is so .shaped as to allow no lateral motion, but only an anteroposterior one. 
The articulation between the capitellum and upper surface of the head of the radius 

is, on the contrary, a ball-and-socket joint. The 
socket, it is true, is shallow, but it is perfectly 
spherical, made so by the rotary movement of the 
radius in pronation and supination. Hence it fol- 
lows that the shape and continuity of the upper ex- 
tremity depends upon the articulation of the ulna 
with the humerus: it further follows that if the 
radius be removed from the elbow-joint the forearm 
would still be held in its proper relation to the arm, 
but if the ulna be removed the stability of the joint 
would be lost and the forearm would move in any 
direction, laterally as well as anteroposteriorly. It 
is for this reason that injuries involving the medial 
condyle and trochlea are more liable to be followed 
by serious disability than are those of the lateral 
condyle and capitellum. 

The movement of the joint takes place around 
a transverse axis, which passes from side to side 
below and in front of the condyles. The forearm 
can be extended to an angle of i8o degrees, or a 
straight line, with the arm. It can be flexed to an 
angle of 30 to 40 degrees. Sometimes it cannot be 
flexed so much, so that if after an injury to the 
joint the patient can flex the elbow to half a right 
angle, or 45 degrees, he may be regarded as hav- 
ing regained a normal amount of motion. 

Carrying Angle. — The axis of motion of the 
joint is not exactly transverse, but slopes slightly 
from the outside downward and inward. The 
effect of this is to give a slight obliquity to the 
motions of flexion and extension. This obliquity 
is not noticeable except in extreme extension and 
flexion. When the forearm is completely extended 
it is seen to lie not in the axis of the arm but to 
bend outward from the elbow at an angle of 170 
degrees. This angle is called the ' ' carrying angle, ' ' 
because by resting the elbow against the side, any article which is carried in the ex- 
tended hand is kept away from the body. Sometimes the line of the forearm is almost 
straight with that of the arm, at others the deflection may amount to 15 degrees. It 
may vary on the two sides and 10 degrees may be considered an average; Woolsey 
gives 6 degrees as the average. This carrying angle becomes lost in certain cases of 
fracture of the elbow, as will be pointed out later. As the elbow is flexed the carrying 
angle disappears (see Fig. 294). 

When flexion is complete the ulna instead of coming up toward the head of the 
humerus inclines inward at an angle of 10 degrees. Morris states that the hand has 
a tendency to point to the middle of the clavicle, which would make an angle of 20 
degrees. This we believe to be too great. 




Fig. 294. — The carrying angle; formed 
by the deviation outward of the axis of the 
forearm from the axis of the arm. 



REGION OF THE ELBOW. 



283 



LIGAMENTS OF THE ELBOW. 

The ligaments of the elbow-joint are four in number — anterior, posterior, internal 
lateral, and external lateral. 

In all joints there are two kinds of ligaments. One kind serves to retain the 
synovial fluid; it is a capsular ligament and is usually thin; the other kind is thick, 
firm, and strong, and is intended to bind the bones together and prevent their dis- 
placement and to limit movemenl:. These two kinds of ligaments often blend 
together so that it is impossible to say where one begins and the other ends; at other 
places they are quite distinct. If an elbow-joint is distended with effusion (or wax) 
the distinction is readily seen. The capsule becomes distended in front and behind, 
while at the sides the ligaments remain closely applied to the bones; hence we learn 
that the anterior and posterior ligaments are capsular in their function while the 
lateral ligaments are retentive. These will be considered more in detail later. 

Superior Radio-nhiar Articulation. — While the superior radio-ulnar articula- 
tion is not considered a part of the elbow-joint proper, it is nevertheless so closely 




Fig. 295. — The external lateral ligament of the elbow- joint, showing its A shape. Its upper end is attached 
to the external condyle of the humerus: its lower ends are attached to the ulna. The circular fibres surrounding 
the head of the radius are called the orbicular ligament. 

associated with it that it cannot be ignored. The head of the radius, in addition to 
its movements of flexion and extension on the humerus, possesses a motion of rotation. 
In order that it may rotate properly the ligaments are arranged in a peculiar manner. 
Its motion in respect to the ulna is a purely rotary one, so that it is bound to the 
ulna by a ligament which encircles its head, called the orbicular ligament. The 
bulk of the ligament encircles three-fourths of the head of the radius and is attached 
at its ends to the anterior and posterior edges of the lesser sigmoid cavity of the ulna. 
Its lower fibres are continuous below the lesser sigmoid cavity, forming a complete 
circle. The upper edge of this orbicular ligament blends with the anterior ligament 
in front, the posterior behind, and the external lateral at the side. We thus see that 
as the anterior and posterior ligaments are capsular in their function the radius is 
kept in place by the external lateral ligament, which branches below in the form of 
the letter Y to blend with the orbicular ligament. When we consider that these 
fibres are hardly inserted at all into the radius, but pass over it to the ulna, it is 
evident that this part of the joint is comparatively weak and not an excessive amount 
of force would be required to pull the head of the radius from beneath the orbicular 



284 



APPLIED ANATOMY 



ligament and so luxate it. The supinator {brevis) arises partly from the orbicular 
ligament and strengthens the joint somewhat. 

The external lateral ligament is a strong band which is attached above to 
the lower portion of the lateral (external) condyle, blends with the orbicular liga- 
ment and is attached below to the ulna along the anterior and posterior edges of the 
lesser sigmoid cavity (Fig. 295). 

The internal lateral ligament is a strong band attached above to the lower 
and anterior portion of the medial (internal) condyle, the groove beneath, and 
descends in the shape of a fan to insert into the inner edge of the coronoid process 
and olecranon (Fig. 296). 

The anterior ligament is capsular in its nature and function, and is a broad, 
comparatively thin membrane which stretches between the lateral ligaments on the 




Fig. 296. — The internal lateral ligament of the elbow- joint, showing its fan-like shape. 

sides and is attached above to the upper edge of the coronoid fossa and below to the 
coronoid process and orbicular ligament. It sometimes possesses a few coarse fibres 
passing downward and outward, but it is mostly very thin, in places barely covering 
the lining membrane. 

The posterior ligament resembles the anterior. It blends on each side with 
the lateral ligaments and is attached above across the upper portion of the olecranon 
fossa and below to the olecranon and posterior portion of the orbicular ligament. It 
also has some cross fibres; but, especially at its upper attachment, it is very weak. 



MUSCLES OF THE ELBOW. 

The elbow-joint is interposed between the long bones of the forearm below and 
the long humerus above. The arm muscles come down and pass over the joint to 
insert close to it in the bones of the forearm. The muscles of the forearm in a similar 
manner cross the joint and are attached comparatively near it to the humerus above. 
Thus we see the joint strengthened by the crossing of the various muscular insertions. 
The elbow having only an anteroposterior motion, the muscles must of necessity be in 
two main groups, one in front and the other behind the joint. 

Lateral Muscles. — It is true that there are lateral muscles but they have little 
or no influence on the movements of the elbow-joint. The medial (internal) condyle 
gives origin to the flexor muscles of the forearm and the pronator radii teres, and 
the lateral (external) condyle gives origin to the extensor muscles; but the bony 



REGION OF THE ELBOW 



285 



attachment of both these sets of muscles coincides too closely with the axis of motion 
to allow of their aiding to any marked extent either flexion or extension of the 
elbow. Their function as far as the elbow is concerned is to aid and strengthen the 
lateral ligaments of their special sides. 

The Anterior or Flexor Muscles. — These comprise the biceps, brachialis 
antiais, brachioradialis, and extensor carpi radialis longior. It will be observed 
that the first two muscles come from above and cross the joint, while the last two 
arise just above the joint to pass down the forearm (Fig. 297). 

The brachialis anticiis arises from the humerus by two heads, one on each 
side of the insertion of the deltoid, and from the anterior surface to just above the 



Inner head of triceps 



Flexor carpi ulnaris 




Biceps 



Brachialis anticus 



Brachioradialis 



Supinator 



Pronator radii teres 



Flexor carpi radialis 



Palmaris longus 



Fig. 297. — View of the antecubital fossa and muscles at the bend of the elbow. 

elbow-joint. It passes over the joint and inserts into the base or lower and inner 
part of the coronoid process. It does not insert into the tip, but some distance 
below. Its function is purely flexion. 

The biceps arises from the upper rim of the glenoid cavity by its long head and 
from the coracoid process by its short head. It inserts into the posterior edge of the 
bicipital tubercle of the radius. Between it and the tubercle is a bursa. About 4 cm. 
( I ^ in. ) above its insertion its tendon gives off a fibrous expansion which passes 
inward to blend with the deep fascia covering the flexor group of muscles. This is 
called the bicipital or semilunar fascia. The biceps tendon passes almost in the 
middle between the two condyles. Along its inner side is the brachial artery, which 
is covered by the bicipital fascia; over this fascia passes the median basilic vein, 
sometimes used for transfusion. The insertion of the biceps is into the radius, which 
is the movable bone, and not into the ulna, which is less so. As a consequence, in 
addition to its function of flexion it acts also as a powerful supinator of the radius. 



286 



APPLIED ANATOMY. 



The extensor carpi radialis longwr arises from the lateral condyle and lower third 
of the supracondyloid ridge and inserts into the base of the second metacarpal bone. 

The brachioradialis or supinator longus arises from the upper two-thirds of the 
lateral (external) supracondyloid ridge above the preceding muscle and as high as the 
insertion of the deltoid. It inserts into the base of the styloid process of the radius. 

These two muscles, owing to their high attachment, so much above the axis of 
motion of the joint, both act as flexors. The brachioradialis also supinates the hand. 

The Posterior or Extensor Muscles. — These comprise the triceps and 
anconeus niiiscles (Fig. 298). 

The triceps arises by its long head from the lower part of the rim of the glenoid 
cavity and adjoining border of the scapula; by its external or lateral head from the 




Triceps 



Olecranon process 

Brachioradialis 

Extensor carpi radialis longior 

External condyle 

Fascial continuation of the triceps 
inserting into the shaft of the ulna 



Anconeus muscle under the fascia 



Fio. 298. — Extensor muscles of the back of the elbow. 



upper outer portion of the humerus from the greater tuberosity above to the radial 
(musculospiral) groove below; by its internal or medial head from the posterior 
surface of the humerus below the radial groove. It inserts into the posterior part of 
the upper surface of the olecranon. Just above its insertion it is separated from the 
bone by a bursa. It is continuous from the outer edge of the olecranon as a firm fascia 
which passes down over the anconeus to be attached to the upper fourth of the ulna 
and the deep fascia. This is an important structure in fractures of the olecranon. 

The anconeus passes downward and backward from the lateral (external) condyle 
to insert into the side of the olecranon and upper fourth of the ulna. Its fibres are 
practically continuous with the lower fibres of the triceps and it may be considered 
as a fourth head of that muscle. It covers the posterior portion of the head of the 
radius and overlaps somewhat the supinator (brevis) muscle. 



REGION OF THE ELBOW. 



287 



SURFACE ANATOMY. 

Having become acquainted with the bones and muscles, one will be better able 
to appreciate the surface markings and understand their significance (Fig. 299). 

When the elbow is fully extended the bony projections are obscured by the soft 
tissues, hence in examining an elbow it should be flexed at approximately a right 
angle. The first object to strike the eye is the prominent olecranon process. It is 
subcutaneous and the bony ulna beneath can be felt and followed down the back of 
the forearm. From the tip upward for a couple of centimetres can be felt the upper 
surface of the olecranon into which the triceps inserts. To feel this distinctly the 
forearm should be slightly extended to relax the triceps; the outline of the upper 
portion of the olecranon then becomes perfectly distinct. 

Projecting on each side of the elbow are the two condyles of the humerus. 
These bony projections do not belong to the forearm. The two condyles are nearly 
on the same level. The medial (internal) is much more prominent and has the 
appearance of being a trifle higher and slightly anterior. A line joining them 



Tendon of triceps — 



Internal condyle 
Olecranon process 



Flexor carpi ulnaris 




Brachioradialis and extensor carpi 
■ radialis longior 



-External condyle 

Depression, head of radius 
-Anconeus 

_ Extensor communis digitorum 
— Extensor carpi ulnaris 
— Subcutaneous surface of ulna 



Fig. 299. — Surface anatomy of the back of the elbow. 

crosses the long axis of the humerus at an angle of 90 degrees, but makes an angle 
of only 80 degrees with the forearm. By deep pressure the lateral (external) supra- 
condylar ridge can readily be felt running up the arm somewhat posteriorly from 
the lateral (external) condyle. The medial (internal) supracondylar ridge is much 
less easily felt though the intermuscular septum is more evident on this side. When 
the elbow is flexed at a right angle a line drawn parallel with the humerus and pro- 
longed through the two condvles will cut the tip of the olecranon. If the forearm is 
extended the olecranon passes slightly posterior to this line; if the forearm is flexed, 
the olecranon passes somewhat in front of it. Hence in examining the elbow for 
injury it is desirable to determine the relation of these points when the elbow is bent 
at a right angle. The coronoid process lies anteriorly, deep in the flexure of the 
elbow, and cannot be distinctly felt. 

If, now, the elbow is extended, the tip of the olecranon can still be felt with the 
medial (inner) condyle to its inner side. Between the two is a deep groove in which 
lies the ulnar nerve. To the outer side of the olecranon is a deep pit or short groove; 
the bone marking its outer edge is the lateral (external) condyle. In the bottom of 
this pit at its lower portion, about 2.5 cm. (i in.) below the tip of the olecranon, can 
be felt the head of the radius. If the thumb is placed on it and the hand rotated, the 



288 \MIWHK» APPLIED ANATOMY. "^^^^^OI^M 

head of the radius can be felt turning beneath. Immediately above the head of the 
radius, lying to the outer side of the olecranon, if the elbow be again flexed to a right 
angle, can be seen and felt the bony projection of the capitellum covered by the 
strong expansion from the triceps. By careful palpation a groove can be felt between 
the lower edge of the capitellum and the head of the radius which marks the limits 
and point of articulation of the two bones. 

On the posterior aspect of the joint the ulnar nerve is the most important struc- 
ture; there is, however, a bursa between the upper or posterior surface of the olec- 
ranon and the skin and also another on its inferior surface, extending downward, 
which from its exposed position is frequently injured and enlarged. Such an 
enlargement occurs from chronic irritation in certain occupations, hence the name 
' ' miners' elbow. ' ' 

With the elbow flexed at a right angle there is seen on its anterior surface a 
crease which runs from one condyle across to the other. If a knife were held parallel 
with the forearm and entered at this crease, it would strike the humerus above the 
level of the joint line, that is, the line of contact of the bones. This joint line runs 
from 1.25 cm. (^ in.) below the lateral (external) condyle to 2.5 cm. (i in.) below 
the medial (internal) condyle. 

Anteriorly the muscular masses form prominent landmarks. In the middle of 
the crease can be felt the tendon of the biceps muscle. The muscular swell above 
the crease is formed by the biceps muscle with the brachialis anticus beneath. The 
sharp upper edge of the bicipital fascia can be distinctly felt when the muscle con- 
tracts. The limits of the biceps can be felt as two lines, radiating like the letter V 
from the biceps tendon upward. These are the commencing bicipital furrows or 
grooves. 

The outer branch marks the depression between the outer edge of the biceps and 
the swell forming the supinator group of muscles. The inner branch marks the inner 
edge of the biceps, and between it and the medial condyle can be felt a muscular 
mass which is formed by the inner portion of the brachialis anticus. In the middle 
of the flexure of the elbow below the crease is a depression called the anteczibital fossa. 
To its outer side is the muscular prominence of the extensors and supinator. To its 
inner side is the muscular prominence of the flexors and pronator. The inner mus- 
cular swell ends at the medial (internal) condyle, but the external one passes well up 
on the arm. The muscles so prolonged upward are the extensor carpi radialis longior 
for about 5 cm, (2 in.) above the lateral (external) condyle, and the brachioradialis 
(supinator longus) for 10 cm. (4 in.) higher. The outer limit of the antecubital fossa 
is formed by the inner edge of the brachioradialis. The inner side is formed by the 
pronator radii teres muscle. 

To the inner side of the biceps tendon lies the brachial artery, which bifurcates 
opposite the neck of the radius, approximately 2 cm. or a finger's breadth below the 
crease of the elbow. Still farther to the inner side lies the median nerve. In the 
groove between the biceps and brachialis anticus on the inner side and brachio- 
radialis (supinator longus) and extensor carpi radialis longior on the outer side lies 
the radial (musculospiral) nerve; it divides above or opposite the lateral (external) 
condyle into the superficial branch and posterior interosseous nerve 

THE VEINS OF THE ELBOW. 

The flexure of the elbow is occupied by a number of veins which are of impor- 
tance from the fact that they are frequently used for purposes of saline infusion, 
sometimes for blood-letting, and not infrequently they are wounded and give rise to 
troublesome hemorrhage. 

They are made more prominent by allowing the arm to hang and by tying a 
bandage firmly above the elbow. The larger part of the blood from the parts below 
is carried by the superficial veins; hence the largest veins lie directly beneath the skin 
and can be seen through it. 

Their arrangement is not always regular but they follow a more or less general 
plan. The blood from the radial side of the wrist and forearm is carried by the radial 
vein. The median vein brings the blood from the anterior surface of the wrist and 



REGION OF THE ELBOW. 



289 



parts abo\'e. There are two veins on the ulnar side, an anterior and a posterior. The 
anterior carries the blood from the anterior ulnar aspect and the posterior ulnar from 
the posterior ulnar aspect of the wrist and forearm. All these veins contain valves 
at intervals of a few inches. The median vein passes up the middle of the anterior 
surface of the forearm, and just below the lower edge of the bicipital fascia communi- 
cates with the deep veins accompanying the radial and ulnar arteries. This commu- 
nication is large, distinct, and always present (Fig. 300). 

The median vein then divides into the median basilic, which passes upward in 
the internal bicipital furrow, and the median cephalic, which follows the edge of the 



Median nerve 



Basilic vein 

Ulnar nerve 

Triceps muscle 



Internal cutaneous 
(antibrachii medialis) nerve 



Brachialis anticus muscle 



Posterior ulnar vein * 



Anterior ulnar vein 



Bicipital fascia 




Brachial artery- 



Biceps muscle 



Median basilic vein 



Median cephalic vein 



Musculocutaneous 
nerve (antibrachii 
lateralis) 

Communication 
between the deep and 
superficial veins 

Radial vein 



Median vein 



Fig. 300. — Veins at the bend ot the elbow. 



biceps to the external bicipital furrow. Three or four centimetres above the bifurca- 
tion of the median, the median cephalic vein is joined by the radial, and from that 
point up it is called the cephalic vein. 

The two ulnar veins just below the medial (internal) condyle or sometimes 

just above it empty into the median basilic vein, which from this point is called 

the basilic vein. Sometimes the two ulnar veins, anterior and posterior, unite and 

empty into the median basilic by a common trunk. The median basilic vein passes 

19 



290 



APPLIED ANATOMY. 



over the bicipital fascia, which separates it from the brachial artery which lies directly 
beneath. The median basilic \ein (or cephalic when more prominent) is usually 
chosen for purposes of saline infusion. It lies to the inner side of the biceps tendon 
and no important structures are liable to be wounded. The terminal filaments of 
the musculocutaneous nerve pass under the median cephalic vein and are not liable 
to be wounded. If the median basilic is chosen for infusion or venesection care must 
be taken not to cut through the bicipital fascia, otherwise a wound of the brachial 
artery may be produced which may result in the formation of a varicose aneurism or 
aneurismal varix. 

When these veins are wounded the bleeding may be very free. Not only are 
the superficial parts drained but likewise the deep parts through the communication 
with the median. We saw one case in which death nearly resulted from such a 
wound made by a piece of tin. When saline infusion is practised the vein selected 
is made visible by compressing it above. It is then cut directly down upon and 
isolated, and the cannula inserted. 

BRACHIAL ARTERY. 



At the bend of the elbow the artery lies to the inner side of the biceps tendon. 



It is beneath the bicipital or semilunar fascia, 
felt opposite the crease. In the lower third 
of the arm the median nerve lies close 
to the artery, but as the bend of the elbow 
is reached it diverges and becomes sepa- 
rated from it by the coronoid head of the 
pronator radii teres muscle. Superficial to 
the deep fascia is the median basilic vein, 
crossed at its upper portion by the cuta- 
neous antebrachii medial is (internal cuta- 



The upper edge of this fascia can be 



m 



Superior profunda (A. profunda 
brachii) 

■ Brachial artery 

Inferior profunda (coUateralis 
ulnaris superior) 



Internal condyle 

Median nerve 

Venae comites 

Brachial artery 

Biceps tendon 




;^ 



Anastomotica magna (collate- 
"ralis ulnaris inferior) 



-Radial recurrent 
-Ulnar recurrent 



Jnterosseous recurrent 
-Posterior interosseous 
"Anterior interosseous 

Radial artery 
-Ulnar artery 



I 



Fig. 301. — Ligation of the brachial artery at the bend 
of the (left) elbow. 



Fig. 302. — Collateral circulation after ligation of the 
brachial artery at the bend of the elbow. 



neous) nerve. The bifurcation of the brachial artery occurs opposite the neck of the 
radius, which is approximately a finger's breadth, or about 2 cm., below the crease of 
the elbow. 

Ligation of the Brachial Artery at the Bend of the Elbow. — The inci- 
sion is laid along the inner edge of the biceps tendon. The median basilic vein is 
usually more prominent than the median cephalic and can be seen obliquely crossing 



REGION OF THE ELBOW. 291 

the artery to reach its inner side. This vein is encountered as soon as the skin is 
divided, hence care is necessary to avoid wounding it. It should be displaced to the 
inner side along with a filament of the cutaneous nerve if this is present. The inci- 
sion is then deepened through the upper portion of the bicipital fascia and the artery 
found beneath, lying in loose fatty tissue and accompanied by two venae comites. 
The median nerve lies to the inner side but may be sufficiently removed not to be 
exposed. The needle is passed from the inner towards the outer side (Fig. 301). 

Collateral Circulation. — On the outer side the profunda (superior) anastomoses 
with the interosseous recurrent (a branch of the posterior interosseous) and radial 
recurrent. On the inner side the superior ulnar collateral (inferior profunda) and 
inferior ulnar collateral (anastomotica magna) anastomose with the anterior and 
posterior ulnar recurrent arteries (Fig. 302). 

DISLOCATIONS OF THE ELBOW. 

In dislocation of the elbow the bones of the forearm are most commonly displaced 
backward. More rarely they may be partially displaced either inwardly or outwardly 
and with or without an accompanying backward displacement. The lateral ligaments 



External condyle 
of humerus 



Head of radius 




Olecranon 
Fig. 303. — Posterior luxation of the elbow; surface view of the outer side. 

are strong, the anterior and posterior weak. The formation of the bones permits 
anteroposterior movement and resists lateral movement; hence the frequency of 
anteroposterior and the rarity of lateral luxations. To understand and recognize these 
dislocations and distinguish between them and fractures requires a knowledge of the 
shape of the bones, the position of the articulations, and especially of the relations 
and significance of the various bony prominences, in other words, surface anatomy. 
In doubtful cases compare the normal with the injured elbow. 

Backward Dislocation of the Elbow. — In backward dislocation the radius 
and ulna are pushed backward and the lower end of the humerus comes forward. It 
is most commonly caused by falls on the outstretched hand and not by direct injury 
to the elbow. 

On the cadaver hyperextension with or even without a slight twisting readily 
produces the displacement. 

The internal and external lateral ligaments are torn loose from their respective 
condyles and the anterior ligament is ruptured. The posterior ligament is stretched 



ag2 



APPLIED ANATOMY 



from the olecranon process to the humerus, and with the periosteum may be hfted 
up but not ruptured. This is especially the case with the periosteum above the 
external condyle, as shown by Stimson. 

The amount of tearing of the muscles depends on the amount of displacement. 
The flexor muscles may be partly torn from the internal condyle or the extensors 
from the external. The brachialis anticus probably will be somewhat torn near its 
insertion in front of the coronoid process. The biceps is not torn but may in some 
cases be caught behind the external condyle. The orbicular ligament remains intact 
and holds the radius in its proper relation to the ulna. 

Signs. — The position assumed by the bones is usually one of slight flexion, 
approximately 120 degrees (Hamilton). 

Viewing the elbow from the side, the anterior portion of the arm above the crease 
is fuller than is normally the case. Posteriorly the olecranon is seen projecting, and 
above it is a distinct hollow. On the outer side of the joint immediately in front of 
the olecranon is seen a prominent projection caused by the head of the radius. It is 




Internal condyle of humerus 



Prominence formed by the trochlea of the 
lower end of the humerus 



Olecranon 
Fig. 304. — Posterior luxation of the elbow; surface view of the inner side. 

to be recognized by placing the thumb on it and rotating the hand. Almost directly 
above it may be felt, — though it is not at all distinct, — the external condyle (Figs. 303 
and 305 ) . On the inner side are seen two rounded bony eminences. The posterior and 
upper of these is the larger; it is the internal condyle. Below and anterior to this is 
another; it is the inner edge of the trochlear articulating surface (Figs. 304 and 306). 

Measurements from the condyle to the acromion process show that they are the 
same on the injured and the healthy sides. Measurements from the condyle to the 
styloid process of the ulna show shortening on the injured side. As the lateral liga- 
ments are torn there is abnormal lateral mobility. If the forearm is placed at right 
angles to the arm, it is seen that the tip of the olecranon no longer lies on a plane 
drawn through the long axis of the arm and the two condyles, but is considerably 
posterior to it. 

The diagnosis as pointed out by Stimson should be based on the positive recog- 
nition of the position of the olecranon, the two condyles, and the head of the radius. 

Treatment. — The lower end of the humerus rests in front of the coronoid process 
(rarely fractured). When the forearm is flexed the triceps becomes tense and holds 



REGION OF THE ELBOW. 



'■93 



the bones locked in their displaced position. The coronoid process prevents the 
humerus from going back into place. To reduce the dislocation, the triceps is to be 




Fig. 305. — Posterior luxation of the elbow, showing the 
position of the bones as viewed from the outer side. 



Fig. 306. — Posterior luxation of the elbow, showing the 
position of the bones as viewed from the inner side. 



relaxed by extending the forearm to an angle of about 120 degrees, thus lowering 
the coronoid process, and extension is to be made on the forearm and counterexten- 
sion on the arm. Usually an anaesthetic is not required (Fig. 307). 

Inward Dislocation of the Elbow. — In inward dislocation the ulna and 



Median nerve^ 



Brachialis anticus 




Tendon of triceps 
Ulnar nerve 

"Olecranon process 



Coronoid process 
Pig. 307. — Dissected preparation of posterior luxation of the elbow, viewed from the inner side, 

radius are pushed toward the inner side. The head of the radius leaves the capi- 
tellum to rest on the adjacent portion of the trochlea. The olecranon slides from the 



294 



APPLIED ANATOMY. 



outer to the inner surface of the trochlea. The outer condyle then becomes promi- 
nent while the inner becomes confused with the olecranon. The identity of the con- 
dyles is always to be established by tracing them up the humerus. This dislocation 
is always incomplete. 

Treatment. — Extension and counterextension with the arm slightly flexed to 




Fig. 308. — Anterior dislocation of the head of the radius. (From author's sketch.) 



release the coronoid process aided by direct pressure on the humerus inward and the 
ulna outward. 

Outward Dislocation of the Elbow. — In outward dislocation the concave 
surface of the olecranon rests on the capitellum and in the groove between it and the 
trochlea. The head of the radius projects far to the outer side of the external condyle. 
The inner condyle and trochlea become quite prominent and can be readily recognized. 

Treatme7it. — Slight flexure of the fore- 
arm. Traction and pressure on the radius 
inward and on the internal condyle and 
lower end of the humerus outward. 

Dislocation of the Head of the 
Radius. — The ulna alone is rarely luxated 
(when displaced it would practically be 
a backward and inward luxation of the 
elbow) but the head of the radius is not 
infrequently pulled out of place (Fig. 308). 
The accident occurs in children, par- 
ticularly young ones who, in walking with 
their elders, are frequently lifted or helped 
along by a pull on the hand. The pull, 
accompanied by hyperextension of the el- 
bow and some adduction of the hand, draws 
the head of the radius from beneath the 
orbicular ligament and then the tension of 
the biceps drags it forward. The displace- 
ment may be either marked or slight. A 
marked displacement in the well-developed 
arm of an adult is readily recognized, but 
in the fat, chubby, undeveloped arm of an 
infant it is easily overlooked. 

Diagnosis. — Pain attracts attention to 
the part. There is apt to be inability to 
flex the arm beyond a right angle, due to 
the radius impinging on the lower end of 
the humerus. Careful palpation reveals a 
hollow below the lateral (external) condyle which should be normally occupied by 
the head of the radius. The outer side of the forearm at the bend of the elbow may 
be abnormally full and pressure here may detect the head of the radius displaced 
forward (Figs. 309 and 310). 

Treatment. — The forearm is to be extended almost to a straight line. Pressure 
is to be made with the thumb to force the head of the radius back into place. While 
this is done the forearm is to be flexed on the arm and if the head is replaced the 




Fig. 309. — Anterior dislocation of the head of the 
radius. Position of bones when viewed from in front. 



REGION OF THE ELBOW. 295 

elbow can be bent to its normal acute angle. On extension being made the radius 
frequently again jumps forward, hence the injury is to be subsequently treated with 
the arm in a flexed position. 



Brachialis anticus 
Biceps tendon 




External condyle 

External lateral liga- 
ment 

Orbicular ligament 



Ulna 
Fig. 310. — Anterior luxation of the head of the radius. 

FRACTURES IN THE REGION OF THE ELBOW. 

The elbow is frequently the seat of fractures, especially in children. Their 
diagnosis and treatment are both difficult and the result sometimes unsatisfactory. 

The bony processes are less distinct in children than in adults and fractures 
sometimes pass unrecognized, being considered sprains, until the persistent disability 
or marked deformity betrays their presence. Luxations and fractures are at times 
mistaken for one another. For these reasons a working knowledge of the anatomy of 
the region is indispensable. 

The fractures that occur in this region are transverse fractures above the con- 
dyles and oblique fractures through the condyles, which may either involve the condyles 
proper (epicondyles so called) and be extra-articular, or involve the articular surface 
of the trochlea or capitellum. Both condyles may be detached by a T- or Y-shaped 
fracture: the olecranon may be fractured and also the head or neck of the radius. 

Transverse Fracture of the Humerus above the Condyles (Supra- 
condylar). — This is the most frequent fracture of the lower end of the humerus. 
The mechanism of its production is not settled. There is little doubt but that it can 
be produced by hyperextension, as the bone fractures at this point when luxation 
does not occur. Hamilton regarded a blow on the elbow as the cause. The line of 
fracture runs transversely across the bone just above the condyles and obliquely 
from behind downward and forward (Fig. 311, page 296). 

Displacemeiit. — The lower fragment is drawn upward and backward and some- 
times there is an angular lateral deformity with obliteration of the carrying angle 
(see page 282). 

Signs. — The overriding of the fragment produces shortening of the humerus as 
measured from the acromion to the lateral (external) condyle. The olecranon projects 
backward, causing a hollow above which resembles that produced in backward lux- 
ation. The flexure of the elbow is fuller than normal. The relation of the condyles 
to the tip of the olecranon is not altered. The condyles may, however, lie posterior 
to a line drawn down the middle of the humerus in its long axis. The sharp edge of 
the lower fragment can sometimes be felt posteriorly. 

Extension of the forearm causes the fragment to be pushed still farther upward. 

Treatment. — There is no single treatment that is applicable to all cases. If the 
arm is too much extended, the biceps and brachialis anticus are made tense, and 



296 



APPLIED ANATOMY. 



tension of either the anterior or posterior muscles tends to favor overlapping and to 
prevent replacement. Full flexion renders the triceps tense. To relax both sets of 
muscles a position at about right angles is probably best. 

Stimson has shown that gunstock (angular) deformity frequently follows this 
injury, hence especial care should be taken to guard against it. It is caused by a 
tilting of the lower fragment. Instead of a line joining the condyles being at right 
angles to the long axis of the humerus, it may be oblique, owing to one condyle 
being higher than the other. Practically it is not possible to recognize this displace- 
ment when the arm is bent at a right angle. The splints will fit the part and every- 
thing appears satisfactory, but on removal of the splints and extension of the forearm 
it may be found that the carrying angle has been destroyed and that a gunstock 
deformity is present. This accident is to be avoided by extending the arm during 
the earlier periods of treatment before the fragment becomes fixed by callus, and 




Triceps muscle 
Ulnar nerve 

Internal condyle 
Olecranon 



Fig. 311. — Transverse fracture of the lower end of the humerus above the condyles. The upper fragment 
is seen to be displaced forward and the lower fragment with the olecranon is displaced backward. This posterior 
displacement is increased by tension of the triceps muscle. 

seeing that, on extension, the forearm makes the same angle with the arm as does 
that of the healthy side. 

The common mode of treatment of supracondylar fractures is the use of antero- 
posterior splints with the elbow bent at a right angle or sometimes acutely flexed. 

Fractures Involving the Condyles. — The condyles (page 280) have been 
described as the lateral bony projections of the lower end of the humerus which are 
extra-articular. Therefore the trochlea and capitellum are not parts of the condyles, 
and the epicondyles are simply the tips of the condyles. 

Bearing this in mind it is evident that fractures involving the condyles may be 
confined to them and not implicate the articular surfaces. They are then extra-artic- 
ular fractures of the condyles, or they can with some reason be called fractures of the 
epicondyles. Other fractures may not only implicate the condyles, but pass through 
them into the articular surfaces. These will be called intra-articular fractures of the 
condyles. The internal epicondyle (epicondylus medialis) is sometimes called the 
epitrochlea. 

Extra-artiailar Fractures of the Condyles or Fractures of the Epicondyles. — The 
medial (internal) condyle projects far beyond the body of the bone as a distinct bony 



REGION OF THE ELBOW. 297 

process, while the lateral (external) condyle is low, flat, and not prominent. For 
these reasons fractures of the medial condyle not involving the joint are more common 
than those of the lateral condyle. In fact e.xtra-articular fractures of the lateral con- 
dyle (detachment of the epicondyle) are almost unknown, but they have been proven 
to exist. 

In extra-articular fractures of the medial condyle, the fragment has been dis- 
placed downward by the flexor muscles which arise from it. To counteract this 
tendency the arm is treated in a flexed position. As the ulnar nerve runs in the 
groove on the posterior surface of the condyle it has also been injured, and vesicles 
and impairment of sensation in the course of the nerv^e have been observed. As 
the articular surfaces are not involved, no serious deformity or disability need be 
expected. 

Intra-articular Fractures of the Condyles. — The line of fracture in these injuries 
usually starts above the epicondyle and passes toward the middle of the bone, 
chipping off a portion of the trochlear surface or the capitellum. Fractures invoh'ing 
the lateral are probably more frequent than those involving the medial condyle. 

Intra-articidar Fracture of the Medial Condyle. — The line of fracture passes 
obliquely through the condyle, entering just above its tip and emerging on the artic- 
ular surface of the trochlea either in the groove sepa- 
rating the two portions of the trochlea or the groove 
between the trochlea and capitellum. As already ex- 
plained (page 282), the integrity of the joint and the 
line of the arm depend on the trochlea and not on 
the capitellum, therefore the farther over toward the 
capitellum the line of fracture goes the more likely is 
there to be lateral mobility (Fig. 312). 

The fragment may be pushed up; this carries the 
ulna up with it while the radius is prevented from 
following by the capitellum. Therefore the forearm 
bends inward, making a lateral deformity. The carry- 
ing angle (page 282) becomes obliterated and what is 

known as gunstock deformity or cubittis varus is pro- 

duced. It is mainly to the researches of Dr. O. H. pio. 312.— Fracture of internal 

Allis that we are indebted for our knowledge of the condyle and trochlea causing gun- 

. , . , . . _,, , "^ , stock detormitv (cubitus varus). 

mechanism of this deformity. 1 he attachment of the From a photograph of a preparation 

n 1 J ^1 it. r i. r • • in the Mutter Museum of the Col- 

flexor muscles does not keep the fragment from rising. lege of Physicians. 
The deformity is difficult to detect when the elbow is 

flexed. The condyles and olecranon and shaft of the humerus may all be in the 
same straight line and still the medial (internal) condyle be higher than normal. If 
the injury is treated with a right-angled splint the radius and ulna remain in their 
proper positions but the ulna and medial condyle may both be higher than normal. 
If this is the case, then, when the forearm is extended, instead of it making an angle 
of 10 degrees outwardly with the line of the humerus, it may incline 10 degrees or 
even 20 degrees inwardly: thus it may deviate as much as 30 degrees from the normal 
direction. To guard against this deformity Allis advised treating the injury with the 
arm in full extension. Any tendency to lateral deformity will then be at once evident 
and can be corrected by additional lateral support. Certain it is that no serious 
fracture of the elbow ought to be treated without frequent examinations of the arm 
in full or almost complete extension being made from time to time, so as to be sure 
this deformity is not becoming established. 

The treatment of fractures involving the joint by placing the elbow in a position 
of complete flexion has been strongly advocated and as a rule is best, although it has 
not entirely superseded other methods in all cases. 

Intra-articnlar Fracture of the Lateral {Fxternal) Condyle. — This is also a fairly 
common injury. The line of the fracture passes from above the tip of the lateral 
condyle down into the joint through the capitellum or between it and the trochlea. 
As is to be expected, this does not show the same tendency to lateral deformity 
as does fracture of the trochlea. When lateral deformity does occur it is be- 
cause the fracture is so extensive as to also involve the trochlea. This, like the 




APPLIED ANATOMY 



other fractures of this region, is to be diagnosed by grasping the fractured part and 
detecting crepitus and excessive mobihty. The medial (internal) condyle is felt 
firmly attached to the humerus and the olecranon to the ulna, but the lateral (ex- 
ternal) condyle is felt to move independently of the others. It is efficiently treated 
by an anterior (not internal) angular splint. 

Intercondylar or T Fracture. — When both condyles are detached there is 
produced what is known as a T fracture. In this injury both condyles are detached 
from each other and from the shaft of the humerus. The line of fracture may vary. 
Sometimes there is a transverse fracture above the condyles with a second line 
passing longitudinally into the joint like the letter T. In other cases the lines may 
be like the letter V or Y (Fig. 313). 

In all these cases the mobility is very marked and the limb can be bent at the 
elbow in any direction. The diagnosis is to be made by grasping the shaft of the 
humerus with one hand and moving each condyle separately with the other. Having' 
determined that each is detached from the humerus, then 
one condyle is grasped in each hand and they are moved 
on one" another, thus establishing the fact of a fracture 
between them. 

In treatment the same care must be exercised to detect 
the occurrence of gunstock deformity as has already been 
advised in fractures of the medial condyle. In these frac- 
tures the fragments are frequently rotated on one another, 
and disability and deformity so often result that in some 
cases it is advisable to fix the fragments in place by some 
operative means. 

Fracture of the Olecranon Process. — The olecra- 
non process may be fractured either close to its extremity 
near the insertion of the triceps tendon, through approxi- 
mately the middle of the greater sigmoid cavity, or toward 
the coronoid process. 

The second is the more common. The fracture which 
occurs nearer the insertion of the triceps is liable to occur 
from muscular action, the triceps contracting and tearing off 
the piece of bone into which it is inserted. The shape of 
the process should be noted. In the bottom of the greater 
sigmoid cavity near where the process joins the shaft it is 
constricted and weakened by a groove which sometimes 
passes nearly or quite across its surface. This is the 
weakest point and is most often the site of fracture. 

The triceps muscle inserts not only into the upper sur- 
face of the olecranon but also along its sides. In addition 
it sends of? a fibrous expansion to each side ; the one to the 
medial condyle is thin, but the one to the lateral condyle 
forms a broad, tough, fibrous band which stretches from 
the olecranon to the lateral condyle and passes down over the anconeus to be 
attached to the outer edge of the upper fourth of the ulna (Fig. 314). In cases of 
fracture the fragment is only slightly displaced upward by the contraction of the 
triceps. The reason is that the fibrous expansion of the triceps usually is not suffi- 
ciently torn to allow of the retraction of the fragment. The amount of separation of 
the fragments is directly proportional to the amount of tearing of the lateral fibrous 
expansion of the triceps tendon. By extending the forearm the triceps is relaxed and 
by pushing the fragment down crepitus can often be elicited. 

Treatment. — Fracture of the olecranon process is usually treated with the elbow 
slightly flexed. Complete extension is not commonly employed. The slight flexion 
allows for the effusion into the joint and leaves the arm sufficiently extended to relax 
the triceps. 

An adhesive strip placed across the back of the elbow above the fragment and 
brought down and crossed on the front of the forearm usually suffices to keep the 
fragment in position. . 




Fig. 313. — Intercondylar 
or T fracture of the lower 
end of the humerus. Mutter 
Museum, College of Physicians. 



REGION OF THE ELBOW. 



299 



The bond of union between the fragments is usually so short that it appears to 
be bony and function is perfect. If the fibrous band is long extension will be incom- 
plete and weak. 

Fracture of the Coronoid Process and Upper End of the Radius. — 
Fracture of the coronoid process does occur but it is exceedingly rare. The brachi- 
alis anticus does not insert into its tip, but at the lower part of its anterior surface. 
The fracture is most liable to occur in cases of luxation, the process being knocked 
of? as the humerus comes forward. 

Fractures of the Head and Neck of the Radius. — The head and neck of the 
radius are rarely fractured. When broken, the line of fracture through the head is 



Ulnar nerve 



Internal condyle ~7^ 



Site of fracture of olecranon 



Posterior surface of the 
upper end of the ulna 




Triceps extensor muscle 



Portion of tendon of triceps which 
inserts into the olecranon process 



External condyle of humerus 



Portion of the tendon of the triceps 
which inserts into the posterior 
surface of the upper fourth of the 
ulna 



Fig. 314. — Fracture of the olecranon process, showing the insertion of the triceps muscle into the olecranon and 

upper fourth of the ulna. 

usually longitudinal and a portion of the head is chipped off. The fragment is liable 
to become displaced, and either creates inflammation and suppuration or becomes 
fixed and greatly interferes with motion. For these reasons the fractured head has 
been frequently excised. A similar displacement may occur when the neck of the 
radius is fractured. 

In this latter injury an anterior angular deformity is said to have been produced 
by the action of the biceps pulling the lower fragment, to which it is attached, 
forwards. 

The classical specimen in the Mutter Museum of the College of Physicians of 
Philadelphia is usually instanced as an example of this action. The possibility of its 
occurrence suggests the treatment of the injury with the elbow flexed to relax the 
biceps muscle. 

Epiphyses of the Bones of the Elbow. — Traumatic epiphyseal separations 
are possible, but so rare as to be seldom detected. Supracondylar fractures in 



300 



APPLIED ANATOMY. 




children, though not infrequently described as separations of the epiphysis are 

probably more often true bony fractures. 

Hufucrus. — The lower end of the humerus ossifies by four centres. Three of 

them, those for the lateral (external) condyle, capitellum and outer portion of the 

trochlea, and inner portion of the trochlea, appear at the twelfth, third, and twelfth 

years and fuse and unite with the shaft at about the six- 
teenth year. The fourth, for the internal condyle, appears 
at the fifth and unites about the seventeenth or eighteenth 
year. The epiphyseal line runs close to the edge of the 
articular surface and is below the level of a transverse line 
joining the upper edges of the two condyles (Fig. 315). 
A true epiphyseal separation would thus be intra-articular 
and would involve comparatively only a thin shell of the 
articular surface. As already stated most of the cases 
regarded as epiphyseal separations are probably true 
supracondylar fractures. 

Destruction or removal of the epiphyseal cartilage 
is, of course, if possible, to be avoided in operations in 
young children, as otherwise interference with the growth 
of the bone will occur. 

U/na. — Most of the olecranon process is a direct 
outgrowth from the shaft of the ulna. At about the 
tenth year a thin shell forms at its extremity which 
unites at the sixteenth year. Therefore fractures which 
pass through the bottom of the greater sigmoid caxity 
are not separations of the epiphysis but true fractures. 

Radius. — The upper articular surface of the radius 
has a centre of ossification which appears from the fifth 
to the seventh year, and unites at the eighteenth to 
twentieth year. 
There is also a centre for the tubercle. Surgical writers as a rule do not speak 

of epiphyseal separations of the upper ends of the radius and ulna. 

DISEASE OF THE OLECRANON BURSA. 

Between the skin covering the olecranon process and the bone is a bursa, 
which, from its exposed position, is not infrequently diseased. It lies in the subcu- 
taneous tissue and resembles in all respects the bursa in front of the patella. In those 
whose occupation causes them to rest frequently on the elbow, this bursa becomes 
enlarged, hence the name ' ' miner's elbow. ' ' The bursa lies on the posterior surface 
of the bone and extends from the tip of the olecranon downward in the direction of 
the forearm. Excision is the most efficient treatment. There are no dangerous 
structures to be encountered in the operation because the bursa does not communi- 
cate with the joint. The position of the ulnar nerve should be borne in mind. It 
can readily be avoided and usually is not seen. There is sometimes another bursa 
on the upper surface of the olecranon just below the insertion of the triceps. It is 
rarely affected. 

DISEASE OF THE ELBOW-JOINT. 

The elbow-joint, like others, is affected with rheumatoid and tuberculous dis- 
ease. The former frequently causes ankylosis, while the latter frequently causes 
suppuration. The joint becomes distended and enlarged. The bony prominences 
of the elbow, while they may not be visible, nevertheless can usually be recog- 
nized by palpation. The lateral ligaments are stronger than the anterior and pos- 
terior, hence the swelling is most marked in front and behind. As the internal lateral 
ligament is stronger than the external lateral, swelling will be more marked on the 
outer side and the medial (internal) condyle will be more easily recognized than the 
lateral (external). 






Fig. 315. — Epiphysis of the 
lower end of the humerus; unites 
with the shaft at about the seven- 
teenth or eighteenth year. 



REGION OF THE ELBOW. 



301 



Pus first works its way posteriorly up behind the tendon of the triceps and then 
sideways and along the intermuscular septa. As the external supracondylar ridge is 
nearer the surface than the internal, pus will show itself sooner above the lateral 
(external) condyle. It may form a protrusion on each side of the triceps tendon and 
olecranon process. 

Later it may show itself anteriorly ; when it does so it appears more to the outer 
than to the inner side, being deflected outwardly through the antecubital space by 
the attachment of the brachialis anticus to the coronoid process, by the tendon of the 
biceps and by the bicipital fascia which passes from the tendon over the muscles 
attached to the medial (internal) condyle. 

RESECTION OF THE ELBOW. 

A straight incision is made over the point of the olecranon a little internal to its 
middle. The upper portion of this incision splits the triceps. Its lower part is 




Ole 



Head of radius 



Capitellum 
-Trochlea 

Internal condvle 



Cut edge of capsule 

Ulnar nerve 

Cut edge of triceps tendon 



Fig. 316. — Resection of the elbow- joint; the ends of the bones are exposed ready to be removed. 

carried down to the bone on the posterior surface of the ulna. The attachment of 
the triceps to the inner side is then dissected off and the ulnar nerve raised from its 
groove without injuring it. The medial (internal) condyle is then to be cleared of 
the muscles attached to it. The parts external to the incision are now to be raised. 
By means of periosteal elevators aided by the knife the external part of the triceps is 
detached from the bone as closely as possible, following exactly the edge of the ulna. 
The anconeus is raised with the triceps and the broad fibrous expansion passing from 
the olecranon to the lateral (external) condyle and thence over the anconeus to be 
continuous with the deep fascia is preserved intact. On the care with which this is 
done depends the amount of subsequent muscular control. As the triceps is turned 
aside the muscles attached to the lateral condyle are raised in the same manner. The 
soft parts being drawn to each side the bones are protruded and the remaining soft 
parts anteriorly can be detached. A flat spatula is then passed beneath the bones 
and the humerus sawed through opposite the upper edge of the medial (internal) 
condyle above and the radius and ulna opposite the lower edge of the head of the 
radius below. The insertions of the biceps and brachialis anticus are not disturbed. 



APPLIED ANATOMY. 

In raising the supinator (brevis) from the upper portion or the radius care 
should be exercised not to wound the posterior interosseous nerve. It runs between 
two planes of muscular fibres in the substance of the supinator (brevis). It is a 
nerve of motion supplying all the extensor muscles with the exception of the anco- 
neus, brachioradialis (supinator longus), and extensor carpi radialis longior; hence 
its injury will be followed by serious paralysis. Almost no vessels require ligation 
(Fig. 316). 

AMPUTATION AT THE ELBOW-JOINT. 

Amputation at this joint is peculiar from the fact of the width of the lower end of 
the humerus. The skin is loose and shows a marked tendency to retract, especially on 
the anterior surface. This, combined with the large, expanded end of the humerus, 



Tendon of biceps. 



Radial (musculospiral) 

nerve, superficial and 

deep branches 



Stump of extensor and 
supinator muscles 




Radial artery 

Internal (antibrachil 
medialis) cutaneous 
nerve 

Median nerve 
Ulnar artery 

Ulnar nerve 

Stump of flexor muscles 



Fig. 317. — Amputation at the elbow- joint. 

requires ample flaps to be made or difficulty will be encountered in properly covering 
the end of the humerus. The irregularity of the line of the joint makes disarticula- 
tion somewhat difficult (Fig. 317). • 

A long anterior flap with or without a short posterior one is usually advised. 
On account of the tendency to retraction the ends of the incision are not carried up 
to the condyles but are kept at least 2.5 cm. (i in.) below them. 

If the flap is cut by transfixion the line of the articulation must be borne in mind. 
Inasmuch as the trochlear surface projects farther down than the capitellum it is 
customary to incline the knife downward and inward. Also, as the trochlear portion 
is thicker, wider, and projects farther than the capitellum, the inner side of the flap is 
made longer than the outer. 

The skin on the anterior surface is loose and retracts freely as soon as cut ; hence 
the muscles are often cut by transfixion. The skin on the posterior surface is not so 
loose and does not exhibit the same tendency to retraction. After the anterior 
muscles have been raised and the short posterior skin flap turned back the joint is to 



THE FOREARM. 303 

be opened. The line of the joint runs from i. 25 cm. below the lateral (ext. ) condyle to 
2.5 cm. below the medial (int.) condyle and is most readily recognized on the outer 
side, hence the division of the ligaments is to be made from the outer toward the 
inner side. The point at which to enter the knife is to be found by first feeling the 
head of the radius in the pit below the lateral (external) condyle posteriorly and then 
by pressure just above the head recognizing the groove between the upper edge of 
the head and capitellum. The knife passes directly traversely along between the 
head of the radius and capitellum, then across the inner portion of the trochlea and is 
then directed downward and inward around the projecting inner portion of the 
trochlea. Division of the internal lateral ligament allows the forearm to be bent back 
and the triceps attachment becomes exposed and can be di\'ided from the front. The 
appearance of the stump will depend on the manner in which the flaps have been cut. 

On each side will be the muscular masses from the internal and external con- 
dyles. Between them will be the tendons of the biceps and brachialis anticus. The 
median and ulnar nerves are to be found, the former to the inner side of the biceps 
tendon and the latter behind the medial (internal) condyle. They are to be short- 
ened. The radial (musculospiral) has already divided into its superficial (radial) and 
deep (posterior interosseous) branches. 

The ulnar and radial arteries will probably be found divided well anterior on the 
face of the stump. Some bleeding may be present from the terminal branches of the 
profunda in front of the lateral condyle, from the superior ulnar collateral (inferior 
profunda) behind the medial condyle, or from the interosseous or recurrent branches. 
It is usually not necessary to apply ligatures to the larger superficial veins. 

THE FOREARM. 

The forearm is intimately associated with the functions' of the hand. It serves 
as a sort of pedestal or support, enabling the hand to be carried away from the body, 
and, by possessing certain movements of its own, — those of pronation and supination, 
— it increases greatly the range and character of the movements which the hand 
is capable of executing. The hand is the essential part of the upper extremity and 
the forearm is subsidiary. Hence we find that, like the neck, the forearm possesses 
nerves and blood-\-essels much larger than its own proper functions would require and 
which are destined for the more important parts beyond. It is composed of two 
bones, the radius and the ulna, which act as the bony support of the part, of a few 
muscles which move these bones and many more which move the hand and fingers 
beyond, and of certain nerves and blood-vessels that not only supply it but also the 
parts beyond. 

BONES OF THE FOREARM. 

The forearm contains two bones, instead of one as in the arm. One of these 
bones, the ulna, is directly continuous with the humerus; the other, the radius, is 
continuous with the hand. In other words, the ulna is associated with the move- 
ments of the arm, and the radius with those of the hand. The large end of the ulna 
articulates with the humerus and its small end is at the wrist, while the large end of 
the radius is articulated with the hand and its small end with the humerus. 

The ulna is the bone which acts mainly as a support. It articulates with the 
humerus by a pure hinge-joint; hence its only motion is one of extension and flexion. 
It is the fixed bone and does not take part in the movements of pronation and supi- 
nation, but serves as an anchoring part for the attachment of the muscles which move 
the radius as well as the hand. At its upper extremity it has attached to it the 
brachialis antiais, triceps, and anco?ieus mzcscles, which flex and extend it. 

At its upper extremity on its outer side is the lesser sigmoid cavity for the articu- 
lation of the radius. Its lower extremity ends in a head tipped with a styloid process. 
The ulna gradually decreases in size from above downward until its lower fourth is 
reached, when it is slightly enlarged to end in the head. At its lower end, the lateral 
aspect of the head of the ulna rests in a cavity in the radius to allow of the movements 
of pronation and supination (Fig. 318). 



304 



APPLIED ANATOMY. 



The radius is small above and gradually increases in size until its lower extremity 
is reached, where it is largest. Its upper portion is composed mainly of compact 
bone with a medullary cavity; lower down as the bone becomes larger it becomes 
more cancellous. Hence it does not follow that it is strongest where it is largest; on 
the contrary it is most often fractured at its lower extremity. About two centimetres 
below the head of the radius is a tubercle. The biceps tendon is inserted into its 
posterior portion and a bursa covers its anterior part, over which the tendon of the 
biceps plays. The radius is the movable bone and to it is attached the hand. 

Stretched across from one bone to the other is the interosseous membrane. Most 
of its fibres run from the ulna upward and outward, so that the shocks received on the 



Flexor carpi ulnaris 

Flexor sublimis digitorum 
Pronator radii teres 



Brachialis anticus 
Supinator (brevis) 

Flexor sublimis digitorum 



Flexor profundus digitorum 



Pronator quadratus 




Biceps 
Supinator (brevis) 



Pronator radii teres 
Flexor sublimis digitorum 

Flexor longus pollicis 



Pronator quadratus 
Rrachioradialis 



Fig. 318. — Anterior view of radius and ulna with areas ot muscular attachments. 



hand are transmitted somewhat to the ulna. On its anterior surface run the anterior 
interosseous arteiy and nerve. About 2.5 cm. (i in.) above its lower end the artery 
pierces the membrane to go to the back of the wrist. 



I 



MOVEMENTS OF PRONATION AND SUPINATION. 

The radius revolves on the ulna about an axis which passes through the centre 
of the head of the radius above and the styloid process of the ulna below, which line 
if prolonged would pass through the ring finger (Fig. 319). In pronation, the hand 
lies with the palm down and the radius is crossed diagonally over the ulna; the bones 
are close together (Fig. 320). In supination the hand lies with the palm up, the 



THE FOREARM. 



305 



bones lie parallel to one another and widely separated (Fig. 321). In the midposi- 
tion the radius lies above the ulna and the space between them is at its maximum. 
The difference in this respect between midpronation and complete supination is 
slight. The head of the radius rotates in the orbicular ligament, the lower end of 
the radius revolves around the head of the ulna and rests on the interarticular trian- 
gular fibrocartilage. The range of movement is from 140 degrees to 160 degrees. 
The radius is pronated by the pronator teres and pronator quadratus muscles. It 
is supinated by the brachioradialis, supinator (brevis), and biceps muscles. Some 
of the other muscles also aid slightly in these movements, especially the flexor carpi 
radialis in pronation. In fractures the preservation of the interosseous space is 
essential for the proper performance of pronation and supination; hence anything 




/ ^ 



Fig. 319. — The axis of rotation 
in pronation and supination. 



Fig. 320. — Position of the bones 
of the forearm when the hand is in 
the position of pronation. 



Fig. 321. — Position of the 
bones of the forearm when the hand 
is in the position of supination. 



which tends to encroach on it, as displacement of the fragments or their position as 
influenced by the position of the hand, is to be guarded against. 

The muscles of supination are much stronger than those of pronation; for this rea- 
son instruments intended to be used in a rotary manner turn from the inside toward 
the outside; that is, in the direction of supination. The screw-driver is an example. 



MUSCLES OF THE FOREARM. 

The movements of the hand and fingers are so intricate and complex as to 
necessitate a large number of muscles for their performance. It is probably easiest 
in order to understand the construction of the forearm to study these muscles in 
reference to their functions. 

The muscles which occupy the forearm form three groups, which have separate 
functions: (i) to flex and extend the fingers; (2) to flex and extend the wrist; (3) 
to pronate and supinate the hand. 



3o( 



APPLIED ANATOMY. 



I. THE FLEXORS AND EXTENSORS OF THE FINGERS. 

The fingers are moved by two sets of muscles, a long set arising from the fore- 
arm and a short set which is confined to the hand. At present we are concerned 
only with the long extensors and flexors which are found in the forearm. 



Brachialis anticus 
Biceps 



Brachioradialis (supinator ]ongus) 



Flexor longus poUicis 



Pronator quadratus. 




Pronator radii teres 

-Flexor carpi radialis 
-Palmaris longus 

Flexor sublimis diRitorum 
Flexor carpi ulnaris 




Fig. 322. — Superficial view of the anterior muscles of the forearm. 

The Flexors of the Fingers. 

The flexors of the fingers consist of three separate groups of muscles: (i) the 
Jlexor profundus digitoriim and flexor longus pollicis, which insert into the distal 
phalanges; (2) the flexor sublimis digitorum ; (3) the palmaris longus which, 
spreading out into the palmar fascia, is attached to the heads of the metacarpal 



THE FOREARM. 



307 



bones and blends with the capsules of the metacarpophalangeal joints. It is an 
additional perforated flexor muscle_(Fig-. 322). 

I. The flexor profundus digitorum is composed of four slips, one for each 
finger, and the flexor longus pollicis (Fig. 323) is a fifth slip that supplies the 



Brachioradialis 

Extensor carpi radialis longioj 
Extensor carpi radialis brevior 



Pronator radii teres 

Flexor carpi radialis 
Palmaris longus 
Flexor carpi ulnaris 



Flexor longus pollicis 

Pronator quadratus 

Stump of flexor carpi radialis 

Flexor sublimis digitorum 




Flexor sublimis digitorum 



Flexor profundus digitorum 



Flexor carpi ulnaris 



Palmaris longus and palm 
"ascia turned down 



Pig. 323. — Dissection showing the muscles of the forearm, especially the long flexor muscles of the fingers. 

thumb. The flexor profundus arises from the anterior surface of the ulna and inter- 
osseous membrane while the flexor longus pollicis arises from the anterior surface of 
the radius and interosseous membrane. Their tendons pass through slits in the 
flexor sublimis digitorum opposite the proximal phalanges to insert into the bases of 
the distal phalanges. 



3o8 ^^^^^^ APPLIED ANATOMY. S 

2. The flexor sublimis digitorum arises from the medial (internal) condyle of 
the humerus, the coronoid process, the intermuscular septa, and the oblique line of 
the radius and divides into four tendons which split in front of the proximal pha- 
langes to allow the profundus to pass through and then unite again and insert into 
the sides of the middle phalanges. There are only four instead of five slips, because 
the thumb has no middle phalanx but only proximal and distal ones (Fig. 323). 

3. The palmaris longus arises from the medial (internal) condyle of the 
humerus and intermuscular septa and inserts into the palmar fascia, which is attached 
to the base of the proximal phalanges, to the heads of the metacarpal bones, and 
blends with the capsules of the metacarpophalangeal joints. It is thus seen to be a 
perforated muscle exactly like the flexor sublimis, which it also resembles in func- 
tion; its attachment is not so far forward. Traction on it tends to flex the proximal 
phalanx. 

The Extensors of the Fingers. 

The extensors of the thumb and fingers arise from the lateral (external) condyle 
and posterior surface of the ulna, radius, interosseous membrane, and intermuscular 
septa. 

Three separate slips forming the extensor longus pollicis, extensor brevis 
pollicis, and extensor ossis metacarpi pollicis go to the thumb. The longus 
inserts into the distal phalanx, the brevis into the proximal, and the ossis into the 
metacarpal bone of the thumb. 

The extensor communis digitorum divides into four slips, one for each 
finger. The slip to the index is reinforced by an additional one called the exten- 
sor indicis proprius muscle. The slip to the little finger is reinforced by the 
extensor minimi digiti (ext. digiti quinti proprius) muscle. They divide 
on the dorsum of the proximal phlanges into three parts, the middle one inserts into 
the base of the middle phalanx, while the two lateral slips insert into the base of the 
distal phalanx. 

2. THE FLEXORS AND EXTENSORS OF THE WRIST. 

The muscles which flex and extend the fingers of course also move the hand 
as a whole, but in addition to these muscles there are five others, — two flexor 
muscles and three extensor muscles, — which are inserted into the bones of the meta- 
carpus and not into the phalanges. When these muscles contract they tend to 
move the whole hand and not the fingers alone. They are the flexor carpi radialis, 
flexor carpi ubiaris, extensor carpi radialis longior, extensor carpi radialis brevior, 
and extensor carpi ulnaris. The palmaris longus has already been described as a 
flexor of the fingers. 

Flexors of the Wrist. 

Flexor Carpi Radialis. — The two flexors of the wrist, the flexor carpi 
radialis and the flexor carpi ulnaris, are both superficial muscles lying directly 
beneath the skin. The flexor carpi radialis arises from the medial (internal) 
condyle of the humerus and intermuscular septa and lies between the pronator 
radii teres externally and the palmaris longus internally. It runs obliquely across 
the forearm, striking the wrist at about the junction of the middle and outer thirds. 
It lies next to and to the outer side of the palmaris longus tendon and to the ulnar 
side of the radial artery and inserts into the front of the base of the second meta- 
carpal bone (Fig. 324). 

Flexor Carpi Ulnaris. — The flexor carpi ulnaris arises by two heads, one 
from the common tendon of the medial (internal) condyle and the other from 
the olecranon process and upper two-thirds of the ulna. The two heads are 
separated by the ulnar nerve, which passes down in the groove between the medial 
condyle and olecranon process. The muscle passes straight down the anterior 
and inner surface of the ulna to insert first into the pisiform bone and unciform 
process and then to continue over to the base of the fifth metacarpal bone. The 
pisiform bone is a sesamoid bone in the tendon of the flexor carpi ulnaris muscle. 



THE FOREARM. 



309 



Both die flexor carpi radialis and the flexor carpi ulnaris flex the hand at the 
wrist. When the ulnaris alone acts it tends to tilt the hand inward; when the 
radialis acts alone it tends to incline the hand outward. Being superficial, these 
muscles are both important landmarks and guides to the arteries. 




Pisiform bone 



Fio. 324. — The flexor muscles of the wrist. Fig. 325. — The extensor muscles of the wrist. 

Extensors of the Wrist. 

Extensor Carpi Radialis Longior. — The extensor carpi radialis longior 
arises from the lower third of the external supracondylar ridge and the lateral 
(external) condyle and inserts into the back of the base of the second metacarpal 
bone. When it contracts it tends to tilt the hand toward the radial side as well 



3IO APPLIED ANATOMY. ^^^^^^^^^H 

as to extend it, and, being attached to the humerus above the line of the elbow- 
joint, it also aids in flexing the elbow. 

Extensor Carpi Radialis Brevior. — The extensor carpi radiaHs brevior 
arises from the common tendon of the lateral condyle and fascia, and, running 
down parallel to the longior muscle, inserts into the base of the third metacarpal 
bone. It is covered by the extensor carpi radialis longior muscle and lies on the 
supinator (brevis). It acts as a pure extensor of the wrist (Fig. 325). 

Extensor Carpi Ulnaris. — The extensor carpi ulnaris arises by two heads, 
one from the lateral ( external j condyle and the other from the posterior surface of 
the ulna through the fascia common to it, to the flexor carpi ulnaris, and to the flexor 
profundus digitorum. It inserts into the base of the fifth metacarpal bone. It extends 
the wrist and tilts the hand toward the ulnar side. 

3. PRONATORS AND SUPINATORS OF THE HAND. 

The movements of pronation and supination have already been described 
(page 304). They are performed by five muscles, two pronators and three supin- 
ators. The pronators are the pronator radii teres and the pronator quadratus. 
The supinators are the brachioradialis (^supinator longus), the supinator {brevis), 
and the biceps. 

Pronators of the Hand. 

Pronator Radii Teres {Round Pronator). — The pronator radii teres arises 
by two heads, one from the medial (internal) condyle and the other, much smaller, 
from the inner surface of the coronoid process. The median nerve passes between 
these two heads. The muscle crosses the forearm obliquely and inserts by a flat 
tendon into the middle of the outer surface of the radius. It rotates the radius 
inward and tends to draw it toward the ulna and flex it on the humerus. The 
influence of this muscle is marked in displacing the radius when fractured. 

Pronator Quadratus {Square Pronator). — The pronator quadratus arises 
from the volar (palmar) surface of the lower fourth of the ulna and inserts into the 
lateral and anterior surface of the radius. By its contraction it rotates the radius 
toward the ulna and in cases of fracture tends to draw the bones together and thus 
endanger the integrity of the interosseous space (Fig. 326). 

Supinators of the Hand. 

Brachioradialis {Supinator Longus) . — The brachioradialis arises from the 
upper two-thirds of the lateral (external) supracondylar ridge of the humerus and 
inserts into the base of the styloid process of the radius. When the hand is in a state 
of pronation contraction of the brachioradialis will tend to supinate it. It also acts 
as a flexor of the elbow, as has already been pointed out. It is superticiai and is an 
important guide both to the radial (musculospiral) nerve and to the radial artery. 

Supinator {Brevis). — The supinator arises from the lateral condyle, the 
external lateral and orbicular ligaments, and the triangular surface of the ulna 
below the lesser sigmoid cavity. It winds around the posterior and external sur- 
faces of the radius and inserts into the upper and outer portion, covering its head, 
neck, and shaft as low down as the insertion of the pronator radii teres muscle. 
It lies deep down beneath the mass of extensor muscles and supinates the radius. 
It is pierced by the deep branch of the radial (posterior interosseous) nerve which 
bears the same relation to it as does the external popliteal nerve to the peroneus 
longus muscle in the leg. 

Biceps Muscle. — The biceps muscle has already been described. Arising 
by its long head from the upper edge of the glenoid cavity and by its short head 
from the coracoid process it inserts into the posterior portion of the tubercle of 
the radius. While its main function is that of flexion of the elbow, still, from the 
manner in which it winds around the tubercle of the radius, it acts as a powerful 
supinator when the hand is prone and it is a disturbing factor in the displacements 
which occur in fractures of the bones of the forearm. 



THE FOREARM. 



3" 



Pronator radii teres 




— Biceps 



Brachioradialis 
(supinator longus) 



Supinator (brevis) 



Pronator quadratus ■ 




^^^ 



Fig. 326. — The pronator and supinator muscles of the left forearm. 



312 



APPLIED ANATOMY. 



SURFACE ANATOMY OF THE FOREARM. 

The forearm has the shape of a somewhat flattened cone, being large above and 
small below. This is because the bellies of the muscles lie above and their tendons 
below. Most of the muscles of the forearm go to the hand and fingers. The 
prehensile functions of the hand require a strong grasp; hence it is that we find 
the flexor muscles on the anterior surface of the forearm much larger and more 
powerful than the extensors posteriorly, and the bones of the forearm, the radius and 
ulna, nearer the surface posteriorly. 

Anterior Surface. — Anteriorly nothing is to be felt except muscles and 
tendons. The extent to which these can be outlined depends on the absence of 



Supinators and extensors 



Tendon of flexor carpi radialis 




Pronator and flexors 



Tendon of palmaris longus 
Transverse furrows 



Fio. 327. — Surface anatomy of the forearm. 



subcutaneous fat and the degree of development and contraction of the individual 
muscles. The skin of the forearm is loose and thin. Through it can be seen 
anteriorly, the median vein going up the middle and the radial vein winding around 
the back of the wrist and crossing the outer edge of the radius about its middle. 
On the inner side near the elbow the anterior and posterior ulnar veins are visible 
passing posteriorly. 

Sometimes there is a slight depression on the inner side below the medial 
(internal) condyle which is caused by the bicipital fascia Ijolding the muscle down. 
The biceps tendon can be felt at the bend of the elbow, and immediately below 
it for the distance of 5 cm. (2 in. ) can be felt a hollow, the antecubital fossa. The 
mass of muscles between it and the ulna on the inside and posteriorly are the 



I 



THE FOREARM. 



313 



flexors and pronator radii teres; the mass of muscles on the outer side between it 
and the radius posteriorly are the extensors, supinator (brevis), and brachioradialis. 
The inner edge of the brachioradialis is indicated by a line drawn from the outer 
side of the biceps tendon to the outer surface of the styloid process of the radius. 
A line from the medial (internal) condyle running obliquely across the forearm to 
the middle of the radius indicates the pronator radii teres muscle. A line from the 
medial condyle to the middle of the wrist indicates the palmaris longus muscle; 
it is sometimes absent. Another line from the same point above to a centimetre 
to the radial side of the palmaris longus tendon at the wrist indicates the flexor 



Triceps tendon 



Internal condyle 
Olecranon process 



Ulna 



Extensor carpi ulnaris 



Styloid process of ulna 




Brachialis anticus 
External bicipital furrow 

Depression, head of radius 

External condyle 

Brachioradialis and extensor 
carpi radialis longior 
Anconeus 



Extensor communis digitorum 



Extensors of the thumb 

Styloid process of radius 
Extensor longus poUicis 



Fig. 328. — Surf ace anatomy of the back of the forearm. 

carpi radialis muscle. The tendons of both these muscles can readily be seen. A 
hne drawn from the medial (internal) condyle to the pisiform bone at the wrist 
indicates the anterior edge of the flexor carpi ulnaris muscle. 

Having located the superficial muscles the arteries and nerves can be traced. 
The brachial artery bifurcates about a finger's breadth below the bend of the elbow. 
A line drawn from the inner edge of the biceps tendon, or a point midway between 
the two condyles, to the anterior surface of the styloid process of the radius indi- 
cates the course of the radial artery. In the upper half of the forearm it is over- 
lapped by the edge of the brachioradialis. In the lower half it is uncovered by 
muscle and lies in the groove formed by the brachioradialis on the outer side and the 
flexor carpi radialis on the inner. The ulnar artery describes a marked curve toward 
the ulnar side until it reaches the middle of the forearm, when it passes down in a 
straight line from the medial (internal) condyle to the radial side of the pisiform bone. 



^^™^^^^^^^ APPLIED ANATOMY. -^^^^^^^m 

The median nerve runs down the middle of the forearm, lying beneath the 
groove separating the palmaris longus and flexor carpi radialis tendons. The ulnar 
nerve runs from the groove between the medial (internal) condyle and olecranon 
process above to the radial or outer side of the pisiform bone below. It lies to the 
ulnar side of the ulnar artery in the lower half of the forearm. The rounded mus- 
cular mass between the edge of the flexor carpi ulnaris and the palmaris longus is 
formed by the flexor sublimis digitorum muscle (Fig. 327). 

Posterior Surface. — The posterior surface differs from the anterior in the 
bones being more conspicuous — they are subcutaneous. Of the two the ulna is the 
more evident. At the elbow the olecranon and the capitellum to its outer side are 
well marked and some distance inwardly is the medial (internal) condyle. By pal- 
pation the ulna can be traced down the forearm almost subcutaneous, running from 
the olecranon process, in a gentle curve toward the median line, down to its styloid 
process at the back of the wrist. It is covered only by the skin and superficial and 
deep fascias. About 3 cm. (i}( in.) to the outer side of the olecranon can be felt 
the lateral (external) condyle and capitellum. If the elbow is extended a dimple 
is seen just below the capitellum ; it marks the position of the head of the radius, 
and by pressure the groove separating the head from the capitellum can be felt. 

By placing the thumb of one hand in the dimple on the head of the radius, and 
rotating the hand of the patient with the other, one can feel the bone rotate and thus 
be assured that the radius is intact. Whenever fracture of the radius is suspected 
this is the procedure resorted to in order to determine whether or not it is broken. 

The radius can be followed only for an inch or so below the dimple, when it 
disappears beneath the muscles to again become subcutaneous on the outer side of 
the forearm, about its middle, from thence it can be followed more or less distinctly 
down to the styloid process on the outer side of the wrist. 

The ulna being subcutaneous, fracture can be determined by palpating it from 
the olecranon down the back of the forearm to the styloid process. 

The line of the ulna is usually marked by the presence of a groove. To the 
ulnar side of the groove lie the flexor carpi ulnaris and the other flexors; to the 
radial side He the extensor carpi ulnaris and the other extensors (Fig. 328). 

From the dimple marking the head of the radius a groove in the muscles can be 
felt which runs to the middle of the outer surface of the radius. Anterior or to the 
palmar side of this groove lie the brachioradialis and extensor carpi radialis longior 
with the supinator (brevis) beneath. The muscles posterior or between the groove 
and the ulna are the extensor carpi radialis brevior, extensor communis digitorum, 
and extensor carpi ulnaris. Passing over the lower third of the outer side of the 
radius are the tendons of the extensor ossis metacarpi poUicis and extensor brevis 
poUicis muscles. As they are here subcutaneous, this is the point at which creaking 
can be felt when they are affected with tenosynovitis. 

ARTERIES OF THE FOREARM. 

A knowledge of the arteries of the forearm is necessary on account of the trouble- 
some hemorrhage which they cause when wounded. 

At the bend of the elbow, a finger's breadth below the crease and opposite the 
neck of the radius, the brachial artery divides into the radial and iihiar arteries. 
These are continued through the forearm to enter the hand, the ulnar anteriorly over 
the annular ligament and the radial posteriorly through the " anatomical snuff-box." 

The ulnar artery is larger than the radial and in its upper half it describes a 
curve with its convexity toward the ulnar side passing beneath the pronator radii 
teres and superficial flexor muscles arising from the medial (internal) condyle. It is 
accompanied by venae comites but not by any nerve in this portion of its course. 
Just above the middle of the forearm the ulnar nerve joins the artery, lying to its 
ulnar side, and accompanies it down into the hand. In the lower half of its course 
the ulnar artery lies to the radial side of the flexor carpi ulnaris muscle, being slightly 
overlapped by it. The flexor sublimis on the radial side also tends to overlap it. 
The covering of the artery, partially at least, by these muscles, together with the 
thickness of the deep fascia and the lack of a proper bony support beneath, cause the 



THE FOREARM. 



315 



pulse from the ulnar artery to be less distinctly felt than that from the radial. When 
the artery passes beneath the pronator radii teres muscle it is crossed by the median 
nerve, which lies superficial to the artery, and is separated from it by the deep head 
of the muscle. The branches of the ulnar artery in the forearm are the anterior and 
posterior ulnar recurrents, the common interosseous, muscular, nutrient, and anterior 
and posterior ulnar carpal branches (Fig. 329). 

The anterior ulnar recurrent runs upward between the edges of the pronator 
radii teres and brachialis anticus. 



Radial recurrent 



Radial artery 
Interosseous recurrent 
Posterior interosseous 



Brachioradialis muscle 



Flexor carpi radialis muscle 



Median nerve 
Superficial volar 




Brachial arterv 



Anterior ulnar recurrent 
Posterior ulnar recurrent 
Ulnar artery 
Common interosseous 

.\nterior interosseous 



Flexor carpi ulnaris muscle 



Ulnar nerve 

Palmaris longus tendon 

Anterior carpal branch of the ulnar 



Fig. 329. — Arteries of the forearm. 

The posterior ulnar rectirrent passes upward with the ulnar nerve behind the 
medial (internal) condyle. 

The common interosseozis artery comes off from the ulnar about 2 to 3 cm. from its 
origin and divides into the volar (anterior) and dorsal (posterior) interosseous arteries. 
The anterior gives a branch to the median nerve — the comes nervi median! — a nutrient 
branch to the radius, and, on reaching the upper edge of the pronator quadratus, sends 
a posterior terminal branch through the membrane and an anterior terminal branch into 
the muscle. The posterior interosseous passes beneath the oblique ligament to the back 
of the forearm and gives of? the interosseous recurrent, which runs up between the lateral 
(external) condyle and the olecranon and then gives branches to the various muscles. 



3i6 ^^^^^ APPLIED ANATOMY. ^^^^^^^^ 

The radial artery, though smaller than the ulnar, seems to be a direct con- 
tinuation of the brachial because it proceeds in the same general direction while the 
ulnar branches off to one side. It is divided into three parts according to the 
region it traverses, viz., the forearm, the wrist, and the hand. It describes a slightly 
outward curved line from a finger's breadth below the middle of the crease of the 
elbow to a point on the front of the radius at the wrist, i cm. (|- in.) inside of its 
styloid process. It is superficial in nearly its entire extent, being overlapped only 
by the edge of the brachioradialis (supinator longus) in its upper third. This 
muscle lies to its outer side all the way down to the styloid process. In the middle 
third the cutaneous branch of the radial nerve lies close to the outer side of the 
artery, but in the lower third the nerve leaves it to become subcutaneous, passing 
more toward the dorsum. 

To the inner side of the artery is the pronator radii teres muscle in its upper 
third and the flexor carpi radialis for the rest of its course. At the wrist it rests on 
the anterior surface of the radius, a centimetre to the inner side of its styloid process. 
By compressing the vessel against the bone its pulsations can be readily felt, and here 
is where the finger is applied in taking the pulse. 

The branches of the radial artery are the recurrent, muscular, anterior radial 
carpal and superficial volar. 

The radial recurrent arises from the radial soon after its origin and follows the 
radial nerve, in the groove between the brachialis anticus and brachioradialis. 

The anterior carpal is a small branch which joins with the corresponding branch 
of the ulnar and anterior terminal branch of the anterior interosseous to form a so- 
called anterior carpal arch which anastomoses with branches of the deep palmar arch 
to supply the bones and joints of the carpus. 

The superficial volar leaves the radial artery just before it crosses the external 
lateral ligament. It pierces the muscles of the thumb to anastomose with a superficial 
branch of the superficial palmar arch. Sometimes this artery is so large that it can be 
seen pulsating as it passes over the thenar eminence from the wrist downward. 

Ligation of the Ulnar Artery in the Forearm. — The ulnar artery between 
the elbow and wrist is so large that when wounded it may require ligation in any 
part of its course. On account of the artery being deep beneath the flexor muscles 
in the upper part of the forearm, the middle and lower portions are to be preferred 
for ligation (Fig. 330). 

Ligation in the Upper Third. — This is done only for wounds. The superficial 
incision may be made in a line from the medial (internal) condyle to the middle 
of the outer border of the radius. The fibres of the pronator radii teres are to 
be parted, not cut, and the artery searched for crossing the wound almost at right 
angles, on a line from the bifurcation of the brachial artery to the middle of the 
inner border of the ulna. The artery is to be found lying between the superficial 
flexor muscles arising from the medial condyle and the deep muscles arising 
from the two bones and the interosseous membrane. It lies beneath the ulnar 
head of the pronator radii teres, which separates it from the median nerve, which 
is superficial to it and nearer the median line. 

Ligation in the Middle Third. — The ulnar artery reaches the inner edge of 
the ulna at its middle and from thence downward runs in a straight line from the . 
medial (internal) condyle to the radial side of the pisiform bone. It lies directly 
under the deep fascia and along the radial or outer edge of the flexor carpi ulnaris 
muscle, which can be made tense by extending and abducting the hand. 

In the upper part of its middle third the artery lies under the edge of the flexor 
sublimis digitorum and the ulnar nerve lies a short distance to its ulnar side. In the 
lower part of the middle third the artery and nerve lie close together, the nerve 
being next to the tendon of the flexor carpi ulnaris. The tendon to the radial side 
of the artery is one of the slips of the flexor sublimis digitorum. 

If difficulty is found in recognizing the edge of the flexor carpi ulnaris after the 
skin incision has been made the hand should be extended and abducted: this may 
make the muscle tense. Sometimes the intermuscular space is marked by a white 
or yellow (fatty) line or by some small blood-vessels coming to the surface at this 
point. The edge of the flexor carpi ulnaris is more likely to be to the radial than to 



THE FOREARM. 



317 



the ulnar side of the skin incision. The needle is to be passed between the nerve 
and artery from the ulnar toward the radial side. 

Ligation hi the Lower Third. — The relations of the artery are practically the 
same as in the lower part of the middle third. In the superficial fascia one of the 
branches of the anterior ulnar vein may be encountered. It should not be mistaken 
for the artery. The artery lies beneath the deep fascia ; the edge of the flexor carpi 
ulnaris muscle should be clearly recognized. The deep fascia is apt to have two 
layers, one passing from the edge of the flexor carpi ulnaris over the flexor sublimis 
while the other, more superficial, goes more to the anterior surface of the annular 



Radial nerve 

Radial artery 

Brachioradialis muscle 



Radial artery 




Flexor carpi ulnaris muscle 
Ulnar nerve 
Ulnar artery 



Flexor carpi ulnaris tendon 
Ulnar nerve 
Ulnar artery 



Fig. 330. — Ligation of the radial and ulnar arteries. 

ligament. Care is to be taken not to work laterally between these layers but to 
isolate and recognize the edge of the flexor carpi ulnaris muscle. 

The ner\e lies between the tendon and artery, which latter has venae comites. 
The needle is to be passed from the ulnar toward the radial side. 



NERVES OF THE FOREARM. 

Injuries of the large nerves of the forearm are followed by much disability. 
When the.se nerves are divided in wounds it is desirable to unite the ends imme- 
diately. The reunion of nerve-trunks which have been divided some time previously 
is also occasionally necessary. 



3i8 



APPLIED ANATOMY. 



These operations demand on the part of the surgeon an accurate knowledge 
of the topography of the part. For our purpose we may consider the nerves of the 
forearm as being of two kinds — trunks and branches. There are two main trunks — 
the median and the ulnar; the superficial (radial), and deep (interosseous) branches 
of the radial (musculospiral), and forearm branches of the median and ulnar form 
the second class. The main trunks simply traverse the forearm to be distributed 
in the hand, therefore injury to them shows itself by disabilities of the hand. The 
branches supplying the forearm, if of sensation, rarely give rise to any serious effects 
requiring surgical interference. The motor branches enter the muscles of the fore- 






N. cutaneus antibrachii lateralis 
(external or musculocutaneous) 

N. radialis, ramus profundus 
(posterior interosseous) 

N. radialis, ramus superficialis 
(radial nerve) 



Brachioradialis muscle 



Median nerve 




N. cutaneus antibrachii 
medialis (internal cutaneous) 



Pronator radii teres muscle 



Ulnar nerve 

Flexor carpi radialis muscle 
Palmaris longus muscle 
Flexor carpi ulnaris muscle 



i si form bone 



Fig. 331. — The nerves of the forearm. 

arm so high up that paralysis usually is seen only when the nerves are injured in 
the region of the elbow or above. The high entrance is caused by the bellies of the 
muscles being above and the part below being tendinous (Fig. 331). 

The Median Nerve. — The median nerve at the elbow-joint lies internal to 
the brachial artery, which lies next and internal to the biceps tendon. It lies on the 
brachialis anticus muscle and under the bicipital fascia. It crosses the ulnar artery 
obliquely a short distance below its origin. The artery curves toward the ulnar side 
while the nerve has a slight curve toward the radial side ; between the two passes the 
ulnar head of the pronator radii teres muscle. The nerve then proceeds downward 



THE FOREARM. 319 

between the superficial and deep layers of muscles. It lies on the flexor profundus 
digitorum and is covered by the flexor sublimis; about 5 cm. above the annular liga- 
ment it becomes more superficial and lies in the interval between the palmaris longus 
and flexor carpi radialis tendons and touching them. It then passes under the annu- 
lar ligament to enter the palm of the hand. A branch of the anterior interosseous 
artery called the comes nervi viediani accompanies the nerve in the forearm. 

Branches. — The median nerve gives ofT muscular, volar (anterior) interosseous, 
an<i palmar cutaneous branches, besides those in the hand. 

The superficial flexor muscles, with the exception of the flexor carpi ulnaris, 
are supplied by branches directly from the main trunk near the elbow ; the one 
to the pronator radii teres usually comes off above the elbow. The deep flexor 
muscles, with the exception of the inner half of the flexor profundus digitorum, are 
supplied by the volar Canterior) interosseous branch. 

The volar {a?iterior) interosseous nerve leaves the main trunk of the median 
just below the elbow and accompanies the volar (anterior) interosseous artery, 
lying on the interosseous membrane between the flexor longus pollicis and the 
flexor profundus digitorum. It supplies the flexor longus pollicis and radial half 
of the flexor profundus muscles as well as the pronator quadratus. 

The palmar cntaneous branch is given off just above the annular ligament and 
comes to the surface between the palmaris longus and flexor carpi radialis tendons. 
It passes over the annular ligament to be distributed to the thenar eminence and 
palm of the hand. 

Wounds of the Median Nerve. — The median nerve may be wounded in 
any part of its course in the forearm, but it is superficial only in its lower portion for 
about 5 cm. above the wrist. From this point up it is covered by the flexor sublimis, 
the flexor carpi radialis and the pronator radii teres. 

While these muscles tend to protect it from injury, if the traumatism is exten- 
sive enough to divide it they render it all the more difficult to treat. Accompanying 
the nerve, especially in the middle third of the forearm, is the comes nervi mediani 
artery, which may cause annoying bleeding. Careless attempts to secure the artery 
may injure the nerve. Should the nerve be divided, paralysis ensues of all the 
superficial flexor muscles except the flexor carpi ulnaris, and of the deep muscles, 
except the inner half of the flexor profundus. This includes the pronator radii teres 
and pronator quadratus, so that the power of pronating the forearm is impaired 
as well as the ability to flex the hand. The flexor carpi ulnaris and outer half (that 
going to the ring and little fingers) of the flexor profundus digitorum are the only 
flexor muscles not paralyzed. 

The paralyzed flexor muscles atrophy and the size of the forearm is much 
reduced. There will also be impairment of the functions of sensation and motion in 
the hand, which will be alluded to later. 

Operations. — ^To find the nerve in the upper third of the forearm an incision 
may be made at the inner side of the biceps tendon and brachial artery. The 
median nerve will be found to the inner side of the artery and may be followed 
down. When the pronator radii teres is reached it must either be drawn to the 
ulnar side or divided. 

The fascial expansion cov^ering the flexor sublimis is next reached; it must be 
slit up and the muscular fibres parted to reach the nerve lying between it and the 
flexor profundus, with the volar (anterior) interosseous nerve alongside. 

To reach the nerve in the middle third of the forearm the guide should be the 
palmaris longus tendon. The nerve lies in a line joining the outer edge of the palma- 
ris longus tendon at the wrist and the brachial artery at the inner side of the biceps 
tendon at the elbow. If an incision is made in the middle of the forearm one comes 
down on the belly of the flexor carpi radialis muscle and it is necessary to part its 
fibres as well as those of the flexor sublimis beneath. If one goes a little lower down 
and places the incision between the palmaris longus and flexor carpi radialis the latter 
may be drawn outward, but the fascia covering the flexor sublimis will still have to 
be incised. The comes nervi mediani artery will be found accompanying the nerve. 

To reach the nerve in its lower third is the easiest because it becomes super- 
ficial about 5 centimetres (2 in. J above the wrist. Here it lies either beneath the 



^i^^^^^^^^"^ APPLIED ANATOMY. ^^^^^^^B 

tendon of the palmaris longus or between it and the flexor carpi radialis. The 
incision should be made between the muscles. A layer of deep fascia will be found 
beneath them, which must be incised. From this point the nerve can be followed up 
beneath the flexor sublimis or downward beneath the annular ligament. Care is to be 
taken not to disturb the tendons of the flexor sublimis at the wrist. 

The Ulnar Nerve. — The ulnar nerve passes downward in the groove on 
the back of the medial (internal) condyle and between the condyle and olecranon 
process. It passes between the two heads of the flexor carpi ulnaris muscle and is 
covered by it, lying on the flexor profundus digitorum ; when half way down the 
forearm it becomes superficial and lies under or at the edge of the flexor carpi 
ulnaris muscle with the ulnar artery and flexor sublimis muscle to its outer or radial 
side. The ulnar artery joins the nerve just above the middle of the forearm. Just 
below the elbow the artery gives off the posterior ulnar recurrent branch, which 
passes up with the nerve behind the medial condyle. From the middle of the 
forearm to the wrist the ulnar nerve lies behind and to the ulnar side of the artery. 

Branches. — It gives muscular branches in the upper third of the forearm to 
the flexor carpi ulnaris and ulnar half of the flexor profundus digitorum muscles. 
It gives small articular branches to both the elbow-joint and wrist-joint. 

It also gives off anterior and posterior cutaneous branches. The anterior, one 
or two, come off about the middle of the forearm ; one supplies the anterior surface 
of the ulnar side of the forearm, while another, called the palmar aitaneous, runs 
down the front of the artery to be distributed to the palm. 

The dorsal or posterior cutaneous branch is given off about 5 cm. (2 in.) above 
the wrist and passes downward and backward beneath the tendon of the flexor carpi 
ulnaris, across the interval between the pisiform bone and styloid process of the ulna, 
over the tendon of the extensor carpi ulnaris, and thence to the fingers. 

Wounds. — This nerve in the forearm is not infrequently wounded. It is 
especially liable to injury in resecting the elbow-joint. From what has been said of 
its course and branches it will be seen that in order for paralysis of any of the 
muscles of the forearm to be produced it must be injured high up in its upper third. 
Then the flexor carpi ulnaris and inner half of the flexor profundus digitorum will 
be paralyzed. If injured lower down the only muscular paralysis which will ensue 
is that of the short muscles of the hand which it supplies. 

If the nerve is divided above the middle of the forearm the anterior cutaneous 
nerves will be involved. If divided between that point and 5 cm. above the wrist 
the anterior cutaneous escapes but the dorsal cutaneous branch is paralyzed. Below 
this latter point the dorsal cutaneous branch escapes and the muscular and sensory 
disturbances produced are on the palmar surface (except the dorsal interossei muscles). 

Operations. — In all operations on the nerve it should be remembered that its 
course is a straight line from the medial condyle to the radial edge of the pisiform 
bone. In the lower half of its course it lies along the outer (radial) edge of the 
flexor carpi ulnaris and this tendon will serve as a guide to it. It is here covered 
only by skin and superficial and deep fasciae, though it may be overlapped by either 
the artery or the edge of the tendon. If it is desired to reach the nerve in its 
upper half it can be followed either from above downward or from below upward, 
the fibres of the flexor carpi ulnaris muscle which cover it being split to the extent 
necessary for proper exposure. Below the middle of the forearm the ulnar artery 
lies to its radial side. Near the elbow the posterior ulnar recurrent artery accom- 
panies it upward, but the nerve is far removed from the ulnar artery in this part of 
its course. 

The Volar Interosseous Nerve and the Superficial and Deep Branches 
of the Radial (Musculospiral). — In addition to the large nerve-trunks of the 
median and ulnar the forearm contains the volar (anterior) interosseous, and the 
deep and superficial branches of the radial (musculospiral) nerve. 

The volar {anterior^ interosseous nerve leaves the median opposite to or below 
the bicipital tubercle of the radius ; it lies on the interosseous membrane to the ulnar 
side of the accompanying volar interosseous artery. It supplies the outer half of the 
flexor profundus digitorum and the flexor longus poUicis muscles, between which it 
lies, and the pronator quadratus muscle. It is rarely wounded alone. 



THE FOREARM. 321 

The deep and superficial branches are the continuation of the radial (musculo- 
spiral) which divides in the groove between the brachioradialis (supinator longus) 
and brachialis anticus muscles just above the elbow. 

The deep branch {posterior interosseous^ is the larger and is a muscular nerve ; 
the superficial branch (radial) is smaller and is solely sensory. The deep branch 
passes down under the brachioradialis and extensor carpi radialis longior and brevior 
muscles and then enters the substance of the supinator (brevis) through which it 
passes to supply the extensor muscles on the back of the forearm and terminates in a 
gangliform enlargement on the back of the wrist. It supplies all the muscles on the 
back of the forearm except the anconeus, brachioradialis, and extensor carpi radialis 
longior, which are supplied directly from the radial (musculospiral) nerve. In 
removing the head of the radius, in resection of the elbow, the supinator (brevis) is to 
be carefully raised from the bone so as to carry the nerve with it and a\'oid injuring it. 
Injury to this nerve causes paralysis of the extensors, and wrist-drop follows. 

The superficial branch {radial^ is purely a nerve of sensation. It passes down 
almost in a straight line and lies to the outer side of the radial «&rtery at the junction 
of its upper and middle thirds. It lies alongside of the artery to its outer side in its 
middle third and then, about 7 or 8 cm. (3 in.) above the wrist, quits the artery, 
passes beneath the tendon of the brachioradialis, and divides into two branches which 
supply sensation to the dorsal (radial) side of the hand and fingers (Fig. 374, p. 361). 

In operating on the radial artery in the middle third of the forearm care should 
be exercised not to include the nerve in the ligature with the artery. 

FRACTURES OF THE FOREARM. 

Fractures of the forearm may involve either the radius or ulna, or both. The 
radius is the bone most often broken. The preservation of the interosseous space 
and functions of pronation and supination are prominent points in treatment. 

Fractures of Both Bones. — These fractures occur either from a direct blow 
on the part or are due to violence in falling on the outstretched hand. They usually 
occur in the middle or lower third. The character of the displacement depends 
more on the manner in which the injury is produced than on the action of the 
muscles, though in some cases they also have some influence. 

The main function of the forearm in addition to that of serving as a pedestal or 
support for the hand is to perform the movements of pronation and supination. It 
is these movements that are most apt to be impaired in cases of fracture. When 
both bones are fractured the interosseous membrane still remains, running transversely 
from one bone to that of the opposite side. Therefore, while it is common enough to 
find the fractured ends displaced toward one another, thus narrowing or obliterating 
the space between them, one never sees a displacement of the fragments produc- 
ing a widening of the interosseous space. In fracture of both bones four types of 
deformity or combinations of these types are found. 

1. The fractured ends of the distal or proximal fragments may preserve approx- 
imately their normal position to one another but be displaced either anteriorly or 
posteriorly or else to one side. When this is the case the displacement is one simply 
of overlapping. If the fragments are displaced laterally from one another then the 
tension of the muscles draws the fragments together and causes them to o\ erlap. 
There is no special direction which this displacement may take. The lower frag- 
ments may be either in front or behind or to either side of the upper ones. The 
position of the fragments varies according to the direction of the fracturing force. 

This displacement is to be remedied by traction on the hand to overcome the 
muscles and bring the broken ends opposite one another, and then by direct pressure 
pushing them as completely as possible back into their normal position. 

The shafts of both bones have muscles arising from them on both their anterior 
and posterior surfaces dnd the sharp fractured ends of the bones not infrequently get 
stuck in the muscular fibres and so prevent proper approximation; non-union may 
be produced by this cause. 

2. The fractured ends of the distal or proximal fragments may be displaced 
toward one another, thus lessening or even obliterating the interosseous space. When 



322 APPLIED ANATOMY. 

the bones are intact they rest on one another at their ends, leaving a space between 
across which stretches the interosseous membrane. The action of this membrane in 
preventing a separation of the fragments has aheady been pointed out, and the 
influence on the fragments of pronation and supination will be discussed further on. 
The two bones, — radius and ulna, — traverse the forearm from the elbow to the 
wrist like two bridges, when they are broken they naturally fall inward toward one 
another. This approximation of the fragments is aided by the muscles, particularly 
the pronators and the brachioradialis. 

The pronator quadratus and teres both pass from the ulna to the radius, the 
one at the lower and the other at the upper portion of the forearm. When they 
contract they naturally tend to draw the bones toward one another. The brachio- 
radialis, arising from the lateral (external) supracondylar ridge of the humerus 
and inserting into the base of the styloid process of the radius, by its contraction 
tends to tilt the upper end of the lower fragment toward the ulnar side. 

Pressure on the bones by bandages wound around the part likewise causes them to 
encroach on the interosseous space, hence the desirability of splints which are wider 
than the forearm so that lateral pressure on the bones by the bandages is prevented. 

3. The fragments may be rotated on one another in the direction of pronation 
or supination and, becoming united in this misplaced position, render the normal 
movements of rotation either much restricted or altogether impossible. 

This axial rotary displacement is due either to the lower fragments being 
dressed in a position of pronation or to muscular action. As has already been 
pointed out (see movements of pronation and supination, page 314), in performing 
the movements of pronation and supination the ulna is the fixed bone and the radius 
is the movable one. When the hand is pronated the radius crosses the ulna 
obliquely and lies almost or quite in contact with it, thus obliterating the inter- 
osseous space. When the hand is in a position of middle or full supination the bones 
are widely separated. When fractures are treated in the prone position it is recog- 
nized that the callus may bind the bones together in their approximated condition 
and a loss of motion will result. 

This is one reason why it is always required to treat these fractures with the 
hand midway between supination and pronation or in complete supination, in which 
position the bones are widely separated. The influence of the supinator muscles, as 
was pointed out by Lonsdale, is also important. As has already been stated, the 
supinators are stronger than the pronators. When the fracture occurs above the in- 
sertion of the pronator radii teres the upper fragment is rotated outward by the 
biceps and supinator (brevis). There are no muscles to oppose them. On this 
account it is necessary to dress the fracture with the hand supinated. When the bones 
are broken below the middle of the forearm the pronator radii teres remains attached 
to the upper fragment and tends to oppose the supinating action of the biceps and 
supinator (brevis). Therefore the fracture is treated with the hand midway 
between pronation and supination. A diminution or loss of the power of pronation 
and supination is a common sequel of fractures of the forearm and is due either to 
an interference with the movement of the bones by callus or displaced fragments or 
by supination of the upper fragment. It is favored by treating the arm in an 
unfavorable position. 

4. The fragments may be inclined toward one another, producing an angular 
deformity. Simple bending at the site of injury produces this displacement. It is 
liable to occur if a narrow band or sling is used to support the injured member. If 
the hand is supported by the sling the arm sags at the seat of fracture. If the fore- 
arm is supported at the site of fracture the hand falls and an angular deformity 
again occurs. Treatment of the fracture with the hand in a supine position on a 
splint with a long sling reaching and supporting the entire length of the forearm will 
obviate and prevent the deformity. 

Fractures of the Shaft of the Radius. — Fractures of the shaft of the radius 
are not common. They are produced by both direct and indirect injury. The hand 
is attached to and articulates mainly with the radius, so that in falls on the hand the 
force is transmitted to the radius, and the shaft of the bone is not infrequently 
fractured in this manner. 



THE FOREARM. 



323 



These fractures are of interest from an anatomical point mainly on account of 
the influence of rotation and muscular action in displacing the fragments. The fore- 
arm possesses the movement of rotation; the radius is the movable bone and rotates 
around the ulna, hence when it is broken 
its fractured ends are readily displaced. 
Fractures of this bone are to be treated 
with the hand in half or full supination 
because in these positions the interosse- 
ous space is preserved. In pronation 
the radius crosses the ulna obliquely and 
lies close upon it and is then most liable 
to be bound to it by callus. A cer- 
tain amount of callus or deformity may 
occur without interfering with the ulna 
opposite. 

It should also not be forgotten that 
most muscles have more than one ac- 
tion. The biceps is both a flexor and 
supinator. The brachioradialis flexes, 
supinates, and exerts a directly upward 
traction on the outer surface of the lower 
end of the radius. 

The fractures of the shaft of the 
radius may be divided into those above 
and those below the insertion of the pro- 
nator radii teres. This muscle inserts 
by a comparatively small tendon into 
the outer and posterior surface of the 
middle of the radius. 

Fractures above the Insertion of the 
Pronator Radii Teres. — ^When the bone 
is fractured above the pronator radii 
teres insertion, and below the tubercle, 
the upper fragment is drawn forward 
and rotated outward by the biceps. If 
the fracture is down close to the upper 
edge of the insertion of the pronator 
radii teres the supinator (brevis) will 
assist in the supination. The lower frag- 
ment will be pronated by the pronator 
radii teres and quadratus. It will be 
drawn toward the ulna by the teres, 
quadratus, and also by the action of the 
brachioradialis. The pronator radii teres 
will also tend to draw the lower frag- 
ment anteriorly. The injury is to be 
treated with the elbow flexed to relax 
the biceps and in a fully supinated posi- 
tion (Fig. 332). 

Fractures below the Insertion of the 
Pronator Radii Teres. — When the frac- 
ture is below the insertion of the pro- 
nator radii teres and above the pronator 
quadratus we have the lower fragment 

drawn toward the ulna by the pronator quadratus and the brachioradialis 
quadratus also tends to pronate the hand (Fig. 333). 

The upper fragment is displaced anteriorly by the flexing action of both the biceps 
and pronator radii teres. The supinator (brevis) and biceps both tend to supinate 
it and the pronator radii teres to pronate it. This tends to place the upper fragment 



-Biceps 



-Supinator (brevis) 

_Brachioradialis (supi- 
"nator longus) 



"Pronator radii teres 



-Upper fragment 



■ Lower fragment 



Deep flexor muscles 



Pronator quadratus 



Fio. 332. — Fracture of the shaft of the radius above 
the insertion of the pronator radii teres muscle. The 
upper fragment is rotated outward by the biceps and 
supinator muscles. 



The 



324 



APPLIED ANATOMY. 



midway between pronation and supination. All fractures of the radius are to be treated 
with the elbow flexed to relax the biceps muscle. It is to be marked that the 
position of the lower fragment follows the position of the hand in pronation and 
supination. Also that by bending the hand toward the ulnar side the lower fragment 
tends to be tilted away from the ulna and thus the interosseous space is increased. 



Biceps- 



Brachxoradialis 



Pronator 
radii teres" 



Site of fracture ■ 
Brachioradialis- 



Pronator 
quadratus - 




Pronator 
quadratus 



FiG- 333- — Fracture of the radius just below the 
insertion of the pronator radii teres muscle. The 
upper fragment is displaced directly forward in a 
position midway between pronation and supination. 



Fig. 334. — -Fracture below the middle of the shaft of 
the ulna, the lower fragment drawn toward the radius 
by the pronator quadratus muscle. 



Pressure with the thumb and fingers between the bones tends to increase the inter- 
osseous space and to some extent to counteract the action of the brachioradialis. 

On account of the upper fragment assuming a middle position the fracture is 
dressed in this position with the thumb upward — an internal angular splint is used. 
Some surgeons prefer using the position of full supination. 

The difference in the width of the interosseous space when the hand is in full 
supination and when it is in semisupination, though it may be slightly in favor of the 
latter position, is too little to give it any preference on that account. 



THE FOREARM. 325 

Fractures of the Shaft of the Ulna. — The shaft of the ulna is more often 
broken by direct violence than is the shaft of the radius. When the arm is raised to 
ward off a threatened blow the thumb is toward the body and it is the ulna which is 
presented externally to receive the impact of the blow, hence its more frequent 
injury. There are two main sites of injury, one just below its middle and the other 
a short distance below the elbow-joint, about at the junction of its middle and upper 
thirds. The former results from the fact that the bone below the middle is smaller 
and weaker than it is above and is not so well covered by muscles. 

Fractures just Below the Middle of the Shaft of the Ulna. — The bones of the 
forearm act as props to separate the hand and elbow. The hand is attached to the 
radius and the radius rests on the capitellum of the humerus, therefore even when the 
ulna is fractured as long as the radius and attachments of the hand are intact there is 
usually but little overlapping of the fragments. 

The lower fragment is most often displaced to the radial side. This is due to 
the action of the pronator quadratus muscle (Fig. 334). 

The upper fragment articulating with the humerus by a pure hinge-joint cannot 
be displaced laterally, but the radius and hand can move bodily toward the ulna, 
being favored in so doing by the pronator radii teres. Thus it is seen that both 



External condyle- 




Tendon of triceps 

Lower fragment Upper fragment Anconeus covered by expansion 

of ulna of ulna of the tendon of the triceps 

Fig. 335. — Fracture through the upper third of the ulna viewed from the outer side. 

Upper and lower fragments have a tendency to incline toward the radius and so 
obliterate the interosseous space and interfere with rotation. 

As to whether the lower or upper fragment will be nearer to the radius will 
depend upon the direction of the line of fracture. If this is from within downward 
and outward, as is the more usual, then the lower fragment will be to the radial side 
of the upper one. 

The treatment of fractures in this locality should be with the hand placed in the 
position of full supination. Hamilton ("Fractures and Dislocations," page 319) 
stated that he had three times seen supination lessened in this injury but never pro- 
nation. The ulna is to be pushed away from the radius by pressure made between 
them with the thumb and fingers and the hand bent toward the radial side. 

Fracture at the Upper Third. — The radius articulates with the upper end 
of the ulna in the lesser sigmoid cavity. Immediately below this is a depression in 
the ulna called the bicipital hollow, intended to accommodate the bicipital tubercle 
when the forearm is pronated. At this point the bone is slightly narrowed and 
then widens ag^ain toward the middle. This constricted part is 7 or 8 cm. (3 in.) 
below the tip of the olecranon process and the spot where fracture is likely to occur. 
When fracture does occur here, if displacement is marked, it produces characteristic 
lesions. The upper fragment may be displaced either posteriorly or anteriorly. 



326 



APPLIED ANATOMY. 



The carrying angle (page 282) formed by the line of the arm with the line of 
the forearm, depends on the integrity of the humerus and ulna and their proper 
articulation. If the ulna is broken high up the forearm is deprived of its support on 
the inner side and it sags inward, thus approximating the bones, obliterating the 
interosseous space, and diminishing the carrying angle. In treatment care should 
be taken that the forearm be not allowed to incline toward the inner side. 

Displacejnent Posterior. — When the displacement is posterior the lower end of 
the upper fragment is tilted backward by the contraction of the triceps muscle. This 
causes a marked projection on the back of the forearm below the elbow (Fig. 335). 

In treating this injury the forearm 
should be placed in at least partial ex- 
tension (complete extension is usually 
not necessary) so as to relax, the triceps 
muscle. 

Displacement Anterior. — When a 
person receives a blow in the region of 
the junction of the upper and middle 
thirds of the ulna on its posterior sur- 
face the fragments are pushed forward 
and an angular deformity is produced, 
the apex of the angle pointing toward 
the anterior surface. The force of the 
blow is not expended entirely on the 
ulna but, having broken it, continues 
and pushes or dislocates the radius for- 
ward (Fig. 336). _ 

In these injuries the fracture of the 
ulna is readily recognized, but the dis- 
location of the head of the radius is often 
overlooked. If the dislocation is not 
reduced subsequent flexion of the elbow 
will not be possible much if any beyond 
a right angle. The contraction of the 
biceps not only favors this luxation by 
pulling the radius forward but tends to 
cause it to recur after replacement. 

Reduction is to be attempted by 
supinating and flexing the foi'earm to 
relax the biceps and making direct 
pressure anteroposteriorly on the radius 
to force the head back into place. The radius may be kept in place by dressing 
the arm with the elbow in a position of complete flexion. 




Fig. 336. — Fracture of the upper third of the ulna, 
with anterior angular displacement of the fragments and 
anterior dislocation of the head of the radius. 



AMPUTATION OF THE FOREARM. 

The lower half of the forearm is so largely tendinous that musculocutaneous 
flaps are unsuitable ; by the time the tendons are cut short there is little tissue left 
but skin, superficial and deep fascia, and a few muscular fibres. 

Amoutation should be performed as low down as one can so as to save as much 
as possible. Artificial appliances, so useful in the lower extremity, are, practically, 
of little value in the upper. The preservation of the power of pronation and supi- 
nation is to be accomplished when the condition permits. The pronator radii teres 
has its insertion in the middle of the radius and if the division of the bone is below 
that point rotary movements will be preserved. 

The surgeon should be acquainted with the position of the main arteries and 
nerves. Four arteries will require ligation : the radial, ulnar, volar (anterior), and 
dorsal (posterior) interosseous. Their position as well as that of the nerves will 
vary accordingly to the site of the amputation. The median and ulnar are the only 
nerves that require shortening. 



THE FOREARM. 



327 



Amputation Through the Upper Third. — The radial artery is to be looked 
for near the surface under the deep fascia, just beneath the edge of the brachioradialis 
muscle. 

The ulnar artery lies between the superficial and deep fiexor muscles somewhat 
toward the ulnar side of the median line. 

The volar interosseous artery lies in front of the interosseous membrane. 

The dorsal interosseous lies between the superficial and deep muscles on the back 
of the forearm more toward the ulnar side. 

The median nerve is to be sought in the middle line of the forearm below the 
superficial flexor muscles. 

The ulnar nerve lies to the ulnar side of the ulnar artery on a level with it and 
beneath the flexor carpi ulnaris muscle. 

Amputation Through the Middle Third. — The radial artery lies beneath 
the deep fascia in front of the radius along the inner edge of the brachioradialis. 



Superficial layer 
of flexor muscles 

Ulnar artery 

Ulnar nerve 

Deep layer of 

flexor muscles' 

Anterior (volar) interosseous. 

artery and nerve 



Ulna, 




Flexor carpi radialis 
Radial artery 

Median nerve 

Brachioradialis (supinator longus) 

Radial nerve 

Pronator radii teres 
Extensor carpi radialis longior 

Radius 

Extensor carpi radialis brevior 



Extensor muscles of fingers 
Fig. 337. — Amputation about the middle of the forearm. 

The ulnar artery here becomes more superficial and lies beneath the radial edge 
of the flexor carpi ulnaris muscle. 

The volar interosseous is found lying on the anterior surface of the interosseous 
membrane or the thin edge of the flexor profundus. 

The dorsal interosseous lies posterior to the membrane between the superficial 
and deep extensor muscles. 

The median nerve is directly in the midline beneath the flexor sublimis and 
above the flexor profundus digitorum. 

The ulnar nerve lies to the radial side of the ulna, to the ulnar side of the ulnar 
artery, and under the flexor carpi ulnaris muscle (F"ig. 337). 

Amputation Through the Lower Third. — The radial artery lies beneath 
the deep fascia between the flexor carpi radialis and brachioradialis. 

The ulnar artery lies to the ulnar side under the deep fascia and at the edge of 
the flexor carpi ulnaris muscle. 

The volar and dorsal interosseous arteries are too small to require ligation. 

The median nerve lies beneath the palmaris longus muscle. At the wrist it lies 
beneath the interval between it and the flexor carpi radialis. 

The ulnar nerve is superficial along the edge of the flexor carpi ulnaris and 
accompanies the ulnar artery along its medial (ulnar) side. 



328 ^^^ APPLIED ANATOMY. 

OPERATIONS ON THE BONES AND OTHER STRUCTURES OF THE 

FOREARM. 

The forearm may require to be operated on for disease or injuries of the bones, 
tumors, foreign bodies, wounds, etc. In operating on this region of the body it is to 
be constantly borne in mind that it contains a multitude of structures each of which 
is essential to the proper performance of some special function. Injury to these 
structures is followed by a corresponding functional disability. Attempts at brilliant 
operating are out of place and the surgeon should be exact, careful, and even tender 
in his handling of the various structures. 

The forearm is mainly nourished by the volar and dorsal interosseous arteries; the 
radial and ulnar pass through it to nourish the hand. These latter are to be avoided. 

The nerves that supply the forearm are given of? high up near the elbow, hence 
they are not usually in danger of injury. The median, ulnar, and superficial branch 
of the radial nerve pass to the hand and they, if possible, are to be avoided. 

It is therefore evident that as far as the arteries and nerves are concerned oper- 
ations in the lower part of the forearm are less dangerous than those in the upper. 
With the muscles it is just the opposite. In the lower half the muscles become ten- 
dinous and soon form groups or masses of tendons. These tendons are separated by 
thin connective-tissue sheaths or synovial membrane which allow them to move freely 
as the muscles contract. Any interference with these sheaths or their contents 
causes an outpouring of inflammatory material that binds them together and fetters 
their action. As healing takes place contraction sets in and the patient is left with a 
useless claw-like hand. For these reasons large incisions and displacements and 
interference with tendons are to be avoided whenever possible. 

As the muscles mostly run longitudinally the incisions should also be longitu- 
dinal. Division of the superficial veins is not liable to cause trouble, but the large 
radial, median, or ulnar veins on the anterior surface may be plainly visible and then 
the incision should be made so as to avoid wounding them. 

The only superficial nerve to be so avoided is the superficial branch of the 
radial. It is alongside of the radial artery in its middle third, but about 7 or 8 cm. 
(3 in. ) above the wrist it leaves the artery and winds under the brachioradialis to go 
down the outer and posterior surface of the radius. It is here to be looked for and 
avoided, as it furnishes sensation to the thumb, index, middle, and half of the ring 
fingers. 

If it is desired to penetrate the muscles their direction is to be remembered. 
The superficial flexor muscles arise from the internal condyle, hence the incision 
should point upward toward it. The direction of the pronator radii teres is from 
the internal condyle to the middle of the radius. The deep fiexors are parallel with 
the bones. 

Posteriorly the extensor group of muscles tends toward the external condyle. 
A third group on the radial side comprises the brachioradialis and the extensor carpi 
radialis longior and brevior. The tendon of the first lies on the outer surface of the 
radius with the other two immediately posterior to it. Crossing the posterior and 
outer surface of the radius in its lower third are the extensor ossis metacarpi pollicis 
and extensor brevis pollicis tendons. 

If it is desired to reach the bones the ulna can be exposed posteriorly where it 
is subcutaneous in its entire length by an incision between the flexor carpi ulnaris 
and extensor carpi ulnaris. The deep fascia is attached to the bone at this point. 

If it is desired to expose the radius, H. Morris {C/m. Soc. Trans., vol. x, p. 138) 
has advised going in between the brachioradialis and the extensor carpi radialis 
longior. He used the superficial branch of the radial nerve as a guide to the desired 
interspace. 

If an incision were made upward from the outer surface of the styloid process of 
the radius one would first encounter the tendons of the extensor brevis pollicis and 
extensor ossis metacarpi pollicis muscles. These being displaced posteriorly would 
reveal the brachioradialis tendon crossing from beneath the posterior border of the 
radius; 5 to 7 cm. (2 to 3 in.) above the styloid process would be the superficial 



THE FOREARM. 329 

branch of the radial nerve. Following the nerve and edge of the brachioradialis 
tendon would lead to the interspace between it and the extensor carpi radialis 
muscle posteriorly. When the middle of the forearm was reached the insertion of 
the pronator teres would be encountered, and from that point up the bone would 
be covered by the supinator (brevis). 

Operations on the median nerve (page 319) and the ulnar nerve (page 320) 
have already been alluded to. 

In operations involving the upper third of the radius the deep branch of the 
radial (posterior interosseous) nerve is liable to be wounded as it passes through the 
supinator (brevis) muscle. It is best avoided by elevating the muscle from the 
bone and raising the nerve along with it, for it does not rest immediately on the 
bone but has some muscular fibres intervening. 

The arteries have already been sufficiently described. 

PUS BENEATH THE DEEP FASCIA. 

The deep fascia of the forearm is continuous with that of the arm. It forms a , 
complete covering for the muscles and sends septa between them. It is especially 
strong posteriorly. It is attached to the medial and lateral condyles of the humerus, 
the sides of the olecranon process and the whole length of the ulna posteriorly. 
Below the medial condyle anteriorly it is strengthened by the bicipital fascia. In 
the antecubital fossa it is pierced by a large communicating vein which connects the 
superficial and deep veins. Toward its lower end posteriorly, it is strengthened 
by transverse fibres and becomes attached to the longitudinal ridges on the radius 
and blends with the posterior annular ligament. 

Below anteriorly it is thin and forms a covering for the tendons of the palmaris 
longus and flexor carpi radialis muscles and at the wrist blends with the annu- 
lar ligament beneath. This latter, as pointed out by Davies CoUey ("Morris's 
Anatomy," page 311), is a continuation of the layer of fascia covering the flexor 
sublimis digitorum. 

When infection in\olves the deep tissues of the forearm the pus, being hindered 
from going externally by the fibrous septa between the various layers of muscles as 
well as the deep fascia itself, tends to burrow up and down the arm. If in the upper 
portion of the forearm, it tends to point in the antecubital fossa. If lower down, it tends 
to come to the surface on the radial side between the flexor carpi radialis and brachio- 
radialis or toward the ulnar side between the palmaris longus and flexor carpi ulnaris. 

The three structures, — the tendons of the palmaris longus and flexor carpi radialis 
and the median nerve, — form a solid barrier anteriorly which inclines the pus to one 
side. Above posteriorly it may work its way upward behind the internal condyle, 
following the ulnar nerve. 

The fibrous septa of the various muscles hinder the progress of pus laterally, and 
the attachment of the deep fascia to the ulna prevents its passing around the arm at 
that point. The many pockets formed by the pus in its burrowing between the 
muscles render these abscesses difficult to drain and tedious in healing. 

Should infection from the thumb travel up the flexor longus poUicis tendon, 
when it reaches above the wrist it is directly beneath the tendon of the flexor carpi 
radialis. In such a case an incision should be made along the radial (outer) edge of 
the tendon, taking care not to wound the radial artery still farther out. If pus infects 
the forearm by following up the flexor tendons of the fingers beneath the anterior 
annular ligament, it shows itself above the wrist between the palmaris longus and 
flexor carpi ulnaris tendons and can here be incised. If it is desired to introduce a drain 
beneath the flexor muscles, an incision may be made along the side of the ulna and a 
forceps passed under the flexor tendons and made to project under the skin of the 
radial side where a counter opening can be made and the drain inserted. (For a dis- 
cussion of the treatment of purulent affections of the hand and forearm see A. B. 
Kavanel : " Surgery, Gynecology, and Obstetrics," 1909, p. 125, vol. viii. No. 3.) 
Suppuration around these tendons is very serious, as the effusion binds together the 
tendons and irritates the nerves and produces disabling contractures which are exceed- 
ingly difficult to remedy. 



APPLIED ANATOMY. 



REGION OF THE WRIST. 



By the wrist is meant the constricted portion of the upper extremity by which 
the hand is joined to the forearm. We will include in its consideration the lower 
portion of the forearm for about 4 cm. ( i ^ in. ) above the radiocarpal joint, and the 




Fig. 338. — Sawn section through the lower end of the radius to show its cancellous structure. 

joint itself. The wrist is so constructed as to permit of the movements of pronation 
and supination of the bones of the forearm, to serve as a support for the hand, and 
to allow movements of the hand in various directions. 



Radius 



Styloid process 

Scaphoid 
Tuberosity of scaphoid 

Trapezium 

Ridge on trapezium 

Trapezoid 




Styloid process 

Semilunar 

Cuneiform 

Pisiform 

■Os magnum 

•Unciform 

•Unciform process 



Fig. 339. — Anterior view of the lower ends of the radius and ulna and the carpal bones. 

BONES OF THE WRIST. 

We may include among the bones of the wrist the lower ends of the radius and 
ulna and the first row of bones of the carpus, — the scaphoid, lunate (semilunar), 
cuneiform, and pisiform. 



REGION OF THE WRIST. 331 

Of the bones of the forearm — the radius and ulna — we have seen that at the 
elbow the ulna is the larger of the two. This is because the main function of the 
ulna is to act as a support to the parts beyond. The radius is intended mainly as a 
means of enabling the hand to perform the functions of pronation and supination. 
At the wrist we find the radius supporting the hand and consequently its lower 
end is large and well dcAeloped. The ulna, on the contrary, contributes but little to 
the support of the hand and does not even enter directly into the wrist-joint, as does 
the radius at the elbow-joint, but ser\'es as a fixed point around which the radius 
rotates. The functional value of the ulna at the wrist is so much less than that of 
the radius as amply to account for its diminished size. 



Radius- 
Posterior radial or thecal tubercle 

Styloid process of radius 

Scaphoid 

Trapezium 

Trapezoid 
Metacarpal bone of the thumb 




Ulna 



Head of ulna 



Styloid process of ulna 
■Semilunar 

Cuneiform 



Os magnum 
Unciform 



Fig. 340. — Posterior view of the lower end of the radius and ulna and the carpal bones. 



Lower end of the Radius. — The lower end of the radius is large and spongy. 
The compact tissue forms a quite thin superficial layer (Fig. 338). Its anterior 
surface is hollowed out to receive the pronator quadratus muscle, with a prominent 
articular edge to which is attached the anterior ligament (Fig. 339). 

The posterior surface is convex and marked with a number of ridges with 
grooves between them which lodge the extensor tendons (Fig. 340). In its middle 
is a prommence, the dorsal radial tubercle, which marks the position of the extensor 
longus pollicis muscle. On its inner side is a concave articular facet, the ulnar notch 
{sigrnoid cavity), for articulation with the ulna; it is plane from above downward, 
thus showing that it permits movement in one direction only, like a hinge. 

Between the lower edge of the ulnar notch and the articular surface is a rough 
ridge that gives attachment to the triangular interarticular fibrocartilage. 



332 



APPLIED ANATOMY. 



The lower or radiocarpal articular surface slopes downward and outward to end 
in the styloid process, which is thereby placed lower than the styloid process of the 
ulna. The articular surface is divided into two facets: the outer is the smaller, 
is triangular in shape, and articulates with the navicular (^scaphoid) bone; the 
inner or larger is quadrilateral and articulates with the lunate {semilunar) bone. 
The styloid process at its base or upper outer portion has inserted into it the tendon 
of the brachioradialis muscle. To its tip is attached the external lateral ligament. 

The Ulna. — The lower extremity of the ulna is rounded in shape, forming its 
head, with the styloid j^rocess projecting downward on its inner and posterior aspect 
To its tip is attached the internal lateral ligament. On its outer side is a rounded 
smooth surface for articulation with the ulnar notch of the radius. The inferior 
or articular surface is flat and rests on the flat interarticular fibrocartilage. 

The navicular (scaphoid), lunate (semilunar), cuneiform, and pisi- 
form bones form the first row of the carpal bones. The pisiform rests on the 
anterior surface of the cuneiform and does not enter into the articulations between 
the hand and bones of the forearm. 

The navicular and lunate articulate directly with the lower end of the radius, 
but the cuneiform articulates with the under surface of the triangular interarticular 
fibrocartilage. 



THE INFERIOR RADIO-ULNAR ARTICULATION. 

The joint between the lower ends of the radius and ulna embraces not only the 
portion between these two bones but also that between the lower end of the ulna and 



Radius- 



Radiocarpal (wrist) joint 

Scaphoid — ,, 

External lateral ligament 




Ulna 



Pronator quadratus 

Inferior radio-ulnar joint 

Triangular fibrocartilage 

Semilunar 

Internal lateral ligament 

Cuneiform 
*L Flexor carpi ulnaris tendon 

Pisiform 



Fig. 341. — ^The wrist-joint and inferior radio-ulnar articulation. 

the upper surface of the triangular fibrocartilage. This latter is attached by its apex 
to a depression on the outer side of the root of the styloid process of the ulna, and 
by its base to the rough line on the radius separating the radio-ulnar from the radio- 
carpal articulation (Fig. 341). 

The Interarticular Triangular Fibrocartilage. — This serves as the main 
bond of union between the lower ends of the radius and ulna. It is strong and 
blends with the internal lateral ligament. Thus the hand has an attachment to the 
inner side of the radius by means of the internal lateral ligament and triangular 
cartilage. 



REGION OF THE WRIST. 



333 



The Capsular Ligament. — The capsular ligament serves to retain the syno- 
vial fluid in the joint. It is thin and filmy and possesses no strength, and therefore 
is useless in limiting movements. 

Anterior and Posterior Radio-ulnar Ligaments. — These ligaments are 
simply a few bands which pass across from the radius to the ulna. They are not 
strong enough to be efficient in limiting mov'ements of the bones. 

Movements. — As has already been pointed out (page 304) 
the movements of pronation and supination have as their axis a 
line drawn through the middle of the head of the radius, the styloid 
process of the ulna, and the ring finger. They embrace in ordinary 
use a range of about 140 degrees which can be increased by forced 
effort to 160 degrees (Fig. 342). 

These movements are limited by various factors, the most 
prominent being in pronation the contact of the soft parts and 
bones, as the radius obliquely overlies the ulna, and in supination 
by the biceps (the most powerful of the supinators) having reached 
the dead centre. 

There is no communication between the radio-ulnar joint 
above and the radiocarpal joint below, except when, as occasion- 
ally happens, the triangular cartilage has a perforation. 

During pronation and supination the lower end of the radius 
moves with the hand, but the lower end of the ulna remains at rest: 
hence it is that the styloid process of the radius always retains the 
same position in relation to the hand. When it is desired to iden- 
tify the styloid process of the radius, one needs only to follow the 
metacarpal bone of the thumb up to the snufl-box at the upper 
edge of which the styloid process can always be felt. Also, to 
identify the styloid process of the ulna, one must not use the hand 
as a guide because the hand changes its position in relation to the 
ulna; but, as the ulna remains quiet, its styloid process can be 
found by following the posterior surface down to its extremity. 

As the interarticular triangular cartilage is fastened by its 
base to the ulnar edge of the radius and by its apex to the base 
of the styloid process of the ulna, it travels with the hand in the movements of 
pronation and supination. 




Fig. 3 42. — Axis of rota- 
tion. 



THE RADIOCARPAL OR WRIST-JOINT. 

The wrist-joint is formed by the radius and triangular cartilage above and the 
navicular (scaphoid), lunate (semilunar), and cuneiform bones below. These are 
joined by the anterior, posterior, internal and external lateral, and capsular liga- 
ments. The two lateral ligaments are strong, well-defined bands, the anterior and 
posterior ligaments are weaker and are fused with the capsular ligament. 

The internal lateral ligament is attached above to the tip of the styloid 
process of the ulna and the tip of the triangular cartilage ; below it is attached to the 
border of the cuneiform bone and is continued on to the pisiform bone. 

The external lateral ligament is attached above to the tip of the styloid 
process of the radius and below to the base of the tubercle of the navicular bone. 

The capsular ligament of the wrist-joint is composed of an anterior and a 
posterior portion strengthened by the two lateral ligaments just described. The 
anterior ligament has the bulk of its fibres running downward and inward from the 
edge of the radius to the palmar surface of the navicular, lunate, and cuneiform 
bones. It is stronger than the posterior. The posterior ligament likewise has 
its fibres running downward and inward to be attached to the first row of carpal 
bones. 

Movements. — The wrist is classed as a biaxial diarthrosis or condyloid joint. 
This means that it is a double hinge-joint having movements around two axes, 
one anteroposterior and the other transverse. A combination of these movements 
results in circumduction, but it has at least no voluntary movement of rotation. 



334 



APPLIED ANATOMY. 



When rotation of the hand occurs it is accompHshed by pronating or supinating- 
the forearm. If the wrist-joint posssssed this latter movement it would be a ball- 
and-socket or enarthrodial joint. The hand can be flexed and extended through an 
arc of approximately 140 degrees and adducted and abducted about half as much. 
The position assumed by the bones in flexion and extension is shown in Figs. 343 
and 344. 

. Adduction or bending toward the ulnar side is much greater than is possible 
toward the radial side. The fact of the ulna not coming so low as the radius 




Scaphoid / / / 

Trapezium / Second metacarpal 

Trapezoid 

Fig. 343. — Position assumed by the carpal bones in flexion of the wrist. 

accounts, at least in part, for this. The lateral ligaments check the movements of 
abduction and adduction, and in addition the contact of the styloid process of the 
radius with the trapezium prevents further outward movement. 

The extent of the movements of the wrist of course varies much in different 
individuals. The laxness of the joints in children, women, and those not accustomed 
to hard manual labor is well known. 

The movements of the wrist are performed by two different sets of muscles. 




Trapezoid 



Trapezium 



Second metacarpal 
Fig. 344. — Position assumed by the carpal bones in extension of the wrist. 

One set comprises the flexors and extensors of the carpus and the other the flexors 
and extensors of the thumb and fingers. 

The first set is composed of the flexor carpi radialis and flexor carpi ichiaris, 
with, which we may perhaps include the palmaris longus, — although it properly 
belongs with the finger muscles, — and of the extensor carpi tibiaris, exteyisor carpi 
radialis h?igior, and extensor carpi radialis brevior. If the fingers are clinched 
and the extensors of the fingers contract they aid the three carpal extensors to bend 
the hand backward. If the fingers are held extended and the flexors of the fingers 
contract they aid the carpal flexors to bend the hand forward. Contraction of the 



REGION OF THE WRIST. 335 

flexor and extensor carpi ulnaris adducts the hand and contraction of the flexor carpi 
radiahs and extensor carpi radiahs longior and brevdor, aided by the short extensor 
of the thumb and extensor ossis metacarpi poUicis, abducts the hand. 

In the affection known as wrist-drop all the extensor muscles are paralyzed. It is 
due to injury, usually from pressure on the radial (musculospiral) nerve, either in the 
groove of the humerus or in the axilla. Although there are a number of synovial 
bursse around the joint in connection with the tendons none communicate with it. 

Muscles. — The flexor tendons cover the wrist anteriorly and the extensors 
posteriorly. With the flexor group we may consider the pronator quadratus. A 
third or radial group comprises the extensor carpi radialis longior and brevior and 
the brachioradialis. 

Anteriorly. — The tendons on the front of the wrist occupy four different planes 
or levels. The most superficial layer embraces the flexor carpi radialis, the palmaris 
longus, and the flexor carpi ulnaris. Of these three the palmaris longus is the 
nearest to the skin as it inserts in the palmar fascia in front of the annular ligament. 
The flexor carpi radialis slips under the upper portion of the annular ligament to 
insert into the base of the second metacarpal bone. The flexor carpi ulnaris inserts 

Flexor carpi ulnaris tendon 
Deep layer of the deep fascia 

Superficial layer of the deep fascia / / ulnar artery 
Anterior annular ligament / / / / Ulnar nerve 



_^.*»Qk,S^'**'' 




Median nerve 
Flexor sublimis tendons 



Tendon of palmaris longus / / / Radial artery 

Superficial layer of deep fascia / Styloid process of radius 

Flexor carpi radialis 

Fig. 345. — Dissection showing the fascias of the anterior portion of the wrist. The superficial layer is 
continuous with the palmaris longus muscle and palmar fascia; the deep layer is continuous with the anterior 
annular ligament. 

into the pisiform bone and continues onward to the base of the fifth metacarpal bone 
and the unciform process of the unciform bone. 

The second layer of tendons is composed of the four tendons of the flexor sub- 
limis digitorum. They fill the space between the palmaris longus and the flexor 
carpi ulnaris. 

The third layer is composed of the four tendons of the flexor profundus digito- 
rum toward the ulnar side and the flexor longus poUicis toward the radial side. 

The fourth and last layer is formed by the pronator quadratus. This lies directly 
on the bones and covers their lower fourth. 

It is sometimes necessary to divide these tendons in cases of contraction of the 
wrist, hence the desirability of being able to recognize and locate them. 

The Deep Fascia and Anterior Annular Ligament. — The deep fascia cov- 
ering the anterior muscles of the forearm is comparatively thin. As it approaches the 
wrist it divides into two layers. The superficial layer is thin and runs over the 
tendons of the palmaris longus and flexor carpi radialis muscles and the ulnar artery 
and nerve. It is continuous below with the palmar fascia. To the ulnar side it 
passes over the flexor carpi ulnaris muscle to be continuous with the posterior annular 
ligament. It is not attached to the ulna, but slides over it as it follows the move* 
ments of the hand in pronation and supination (Fig. 345). 



33^ 



APPLIED ANATOMY. 



-Extensor carpi radialis brevior 
-Extensor carpi radialis longior 



The deep layer of the deep fascia covers the flexor sublimis digitorum and 
passes downward beneath the flexor carpi radialis and brachioradialis muscles. It is 
continuous below with the anterior annular ligament. 

The deep layer blends with the superficial layer to the radial side of the flexor 
carpi radialis, and then merges with the posterior annular ligament to form the sheath 
of two of the extensor muscles of the thumb. 

On the ulnar side the deep layer passes over the ulnar artery and vein and under 
the flexor and extensor carpi ulnaris muscles, forming the posterior portion of their 

sheaths, and then merges with the pos- 
terior annular ligament. 

The anterior a^inular ligament is 
attached on the ulnar side to the pisi- 
form bone and unciform process of the 
unciform bone and on the radial side 
to the trapezium and tuberosity of the 
navicular (scaphoid). 

Over the anterior annular liga- 
ment pass the ulnar artery and nerve, 
-Brachioradialis (supinator longus) the superficial volar artery, and the 

palmar cutaneous branch of the median 
nerve. 

Beneath the annular ligament pass 
the median nerve, the flexor sublimis, 
flexor profundus, and flexor longus pol- 
licis tendons. These tendons are em- 
braced in two sheaths, one for the 
flexor longus pollicis and the other for 
the flexors of the other four fingers, 
the sheath for the little finger extend- 
ing to the insertion of the profundus 
tendon into the distal phalanx. The 
tendinous sheaths accompany the ten- 
dons for a distance of 2.5 to 5 cm. ( i 
to 2 in.) above the annular ligament. 
Posteriorly. — On the posterior 
surface of the wrist the tendons may 
be divided into two groups, an exten- 
sor group and a radial group. The 
extensor group is divided into a super- 
ficial and deep set. The superficial set 
is composed of the extensor communis 
digitorum, the extensor minimi digiti 
and the extensor carpi ulnaris. The 
deep set is composed of the extensor 
ossis metacarpi pollicis, extensor brevis 
pollicis, extensor longus pollicis, and extensor indicis. The radial gro7cp, on the 
posterior and outer surface of the radius, is composed of the extensor carpi radialis 
longior, the extensor carpi radialis brevior, and the brachioradialis (Fig. 346). The 
first two lie beneath the deep extensor muscles, thus practically forming a third layer. 
All the tendons of the posterior and radial group of muscles, with the exception of 
the brachioradialis, pass beneath the posterior annular ligament into the hand. The 
brachioradialis inserts into the base of the styloid process of the radius. 

Posterior Annular Ligament. — As the tendons pass down over the posterior 
surface of the radius and ulna they are bound down by processes of the deep fascia 
which form canals in which they run. The deep fascia of the posterior surface of 
the forearm in the neighborhood of the wrist is strong, and forms the posterior 
annular ligament. Its lower border is about level with the upper border of the 
anterior annular ligament. It is attached externally to the posterior and outer edge 
of the styloid process of the radius and internally to the posterior surface of the 



-Extensor ossis metacarpi pollicis 
-Extensor brevis pollicis 
"Styloid process of radius 

• Extensor carpi radialis longior 

- Extensor carpi radialis brevior 

- Extensor longus pollicis 



-I 



S 



Fig. 346. — Muscles of the radial side of the wrist. 



REGION OF THE WRIST. 



337 



styloid process of the ulna, the internal lateral ligament, the pisiform, and adjacent 
carpal bones. Beneath this posterior annular ligament are six compartments. From 
the radial toward the ulnar side they are : (i) One on the outer side of the styloid 
process of the radius for the extensor ossis metacarpi poUicis and extensor brevis 
poUicis; (2) for the extensor carpi radialis longior and brevior, then comes the 
posterior radial tubercle in the middle of the radius, and passing close along its ulnar 
side is (3) the extensor longus pollicis. To the ulnar side of this tendon is a com- 
paratively broad sheath for (4) the extensor communis digitorum and the extensor 



Extensor ossis metacarpi pollicis 
and extensor brevis pollicis 

Extensor carpi radialis longior 
and extensor carpi radialis brevior 



Extensor longus pollicis. 




Extensor carpi ulnaris 



Extensor minimi digit! 



Extensor communis digitorum 
and extensor indicis 



Fig. 347. — The sheaths of the extensor tendons on the back of the wrist distended with wax to show their extent. 



indicis muscles. In the interval between the radius and ulna lies (5) the tendon of 
the extensor minimi digiti, and on the posterior side of the styloid process of the ulna 
is (6) the tendon of the extensor carpi ulnaris (Fig. 347). 

Each of these six compartments is lined with a separate sheath which extends 
under the annular ligament from a centimetre or two above the joint to about the 
bases of the metacarpal bones on the dorsal surface of the hand. 

The Anatomical SnufF-Box (la tabatiere anatomique, of Cloquet). — 
On the outer dorsal aspect of the wrist, just below the radius, is a depression particu- 
larly noticeable when the thumb is abducted (Fig. 351, page 341). It is triangular in 



338 



APPLIED ANATOMY. 



shape with its base upward. The styloid process of the radius forms its base ; 
the extensor brevis polUcis with the extensor ossis metacarpi polHcis forms its radial 
or outer side, and the tendon of the extensor longus poUicis forms its ulnar or inner 
side. Its floor is formed by the navicular (scaphoid) and trapezium bones. 
Through it, lying on these bones and the external lateral ligament, passes the radial 
artery on its way to the first interosseous space. Superficial to the artery lies a 
vein and some fine branches of the radial nerve. In ligating the artery at this point, 



Radial vein 
Posterior radial tubercle 

\ JIS / / / 1/ 

Posterior ulnar vein 



Extensor ossis metacarpi pollicis 
and extensor brevis pollicis 

Extensor carpi radialis longior 

Extensor carpi radialis brevior 

Radial artery in snuff-box" 

Extensor longus pollicis 

Abductor indicis. 




Posterior annular ligament 



\0 \^ 



Fig. 348. — View of the anatomical snuff-box and the radial artery passing through it. 

care should be taken not to mistake the vein for it ; the vein is near the skin, the 
artery lies deep on the lateral ligament and bones (Fig. 348). 



SURFACE ANATOMY OF THE WRIST. 

The bellies of many of the muscles, mainly the superficial ones, cease as they 
become tendinous about the middle of the forearm. Hence the rapid decrease 
in size as one descends. When the wrist is reached there is a swelling on each side 
caused by the expanded lower end of the radius on the outer side and the head of 
the ulna on the inner. The medial (inner) prominence is rendered more marked by 
abducting the hand, the lateral (outer) prominence by adducting it. Just beyond 
these there is a constriction as the wrist passes into the hand. 



REGION OF THE WRIST. 339 

Above the wrist on the anterior and outer part can be felt the radius. Its lower 
2 or 2. 5 cm. (i in.) is sharp and prominent — this is the anterior border of the styloid 
process. On the outer side at its base is the point of insertion of the brachioradialis 
tendon. Following the bone down on its outer side, at the upper margin of the 
anatomical snuff-box, one feels the tip of the styloid process, a most important 
landmark. 

On the outer surface of the radius beginning below between the tip of the styloid 
process and its sharp anterior border are the extensor ossis metacarpi pollicis and 
extensor brexis pollicis tendons. They can readily be seen and felt when the thumb 
is extended as they cross obliquely over the lower end of the radius. The sheaths 
of these tendons frequently become inflamed from injuries, causing what is termed 
tenosynovitis. If the hand is laid on the lower portion of the radius of a patient so 
affected, and he is told to move the thumb, a characteristic creaking can be felt as 
the tendons move in their inflamed sheaths. 

The edge of the articular surface of the radius can be indistinctly felt from the 
tip of the styloid process to the edge of the flexor carpi radialis internally and across 
the back of the wrist in an upwardly curved line toward the ulna. 

On the inner side of the wrist can be felt and seen the prominence made by the 
head of the ulna. The ulna is subcutaneous and can be followed up the forearm 
posteriorly its entire length. It is not covered by muscles on its inner border, but 
on its anterior surface is the flexor carpi ulnaris tendon beneath which is the flexor 
profundus digitorum, this latter being separated from the bone by the origin of the pro- 
nator quadratus. If the posterior surface of the ulna is followed downward the styloid 
process forming its extremity can be distinctly felt, especially if the hand is placed 
in the supine position and slightly flexed. Overlying the head of the ulna posteriorly 
is the tendon of the extensor carpi ulnaris muscle going to the base of the fifth meta- 
carpal bone. This tendon follows the movements of the hand in pronation and 
supination, but the styloid process of the ulna remains stationary. When the hand is 
pronated the tendon lies to the anterior side of the styloid process, but when the hand 
is supinated it lies toward its posterior side. This tendon cannot be readily recognized. 

The inner and posterior surface of the cuneiform bone can be felt immediately 
below the head of the ulna. Some difficulty may be experienced in distinguishing 
one from the other; if, however, the hand is abducted and adducted the cuneiform 
bone can be felt to move while the ulna remains stationary. On the palmar surface 
of the wrist, immediately below the ulna, can be felt the distinct bony prominence 
formed by the pisiform bone. The flexor carpi ulnaris inserts into it. 

About 2 to 2. 5 cm. ( I in. ) below and to the radial side of the pisiform bone is 
the unciform process of the unciform bone. It is best detected by laying the ball of 
the thumb over the spot and making deep pressure with a rolling motion. On the 
radial side of the anterior surface, directly in line with the tendon of the flexor carpi 
radialis, is the prominent tubercle of the navicular (scaphoid) bone; a centimetre 
farther on, in line with the thumb, is the ridge of the trapezium. The anterior annular 
ligament is attached to its outer surface about 2.5 cm. (i in. ) below the styloid proc- 
ess of the radius ; a bony prominence formed by the trapezium marks its junction 
with the metacarpal bone of the thumb in front. 

The ability to locate the carpometacarpal joint of the thumb is of importance 
in reference to the diagnosis of fractures and other injuries. On comparing the two 
styloid processes it will be seen that the styloid process of the radius extends i cm. 
(fin.) lower than that of the ulna. This is best observed with the hand in a prone 
position. Across the front of the wrist there are two transverse lines. The proxi- 
mal or upper one corresponds with the radiocarpal joint or wrist-joint. The distal or 
lower one corresponds with the joint between the two rows of carpal bones and 
marks the upper edge of the anterior annular ligament. 

On the posterior surface of the wrist, one-third of the width of the wrist across 
from the edge of the radius, can be felt a bony prominence. It is the posterior radial 
tubercle. If the thumb is extended the tendon of the extensor longus polhcis leads 
directly to the tubercle and lies along its ulnar border. This tubercle marks the middle 
of the posterior surface of the radius. The radius passes two-thirds across the wrist 
and the ulna the other third ; by firm pressure the interval between them can be felt. 



340 



APPLIED ANATOMY. 



If the hand is firmly clenched and flexed on the forearm the tendons on the 
anterior surface of the wrist become prominent. The most evident is the palmaris 
longus which, though sometimes absent, usually stands out clear and sharp. Lying 



Line indicating the joint 

between the first and second 

row of carpal bones 

Pisiform bone 

Line indicating the 
radiocarpal joint 



Flexor carpi ulnaris muscle 
Ulnar artery and nerve 




Styloid process of radius 

Groove for radial artery 

Swelling formed by the 
extensors of the thumb 

Flexor carpi radialis 

Palmaris longus 

Median nerve 



Fig. 349. — Surface anatomy of anterior surface of wrist. 




Tuberosity of 
the scaphoid 



Flexor carpi radialis 

Styloid process of radius 

Palmaris longus 



Pisiform bone 
Prominence formed 
by the flexor sublimis 
digitorum 
Flexor carpi 
ulnaris muscle 



Fig. 350. — Surface anatomy of the anterior portion of the wrist. 

along its radial border is the tendon of the flexor carpi radialis; between the two on 
a lower level lies the median nerve. In front of the ulna, and going directly down- 
ward to the pisiform bone, is the tendon of flexor carpi ulnaris (Fig. 349). 



REGION OF THE WRIST. 



341 



If the hand is extended the tendon of the flexor carpi ulnaris stands out clearly. 
In the hollow to its lateral (outer) side lie the ulnar nerve and artery. A rounded 
muscular swell fills the space between the ulnar artery and the tendon of the palmaris 
longus, — it is caused by the flexor sublimis digitorum (see Fig. 350). It is here 
that abscesses show when they travel up from the hand. 

Between the outer edge of the flexor carpi radialis tendon and the anterior outer 
edge of the radius is a groove in which runs the radial artery. The position of the 
extensor ossis metacarpi poUicis and extensor brevis pollicis which run together over 
the outer surface of the radius can best be determined by abducting the thumb and 
so making these tendons prominent (Fig 351). 




Extensor longus pollicis 

Extensor brevis pollicis 

and extensor ossis metacarpi 

pollicis 

Anatomical snuff-box 

Tip of styloid process of 
radius 



Fig. 351. — Surface anatomy of the outer dorsal portion of the wrist, showing the anatomical snuff-box. 



In the same manner the extensor longus pollicis tendon can be made prominent 
and followed to the posterior radial tubercle. By firm pressure the upper limits of 
the first and second interosseous spaces can be felt. They mark the bases of the 
metacarpal bones. The extensor carpi radialis longior passes across the snuff-box to 
insert into the radial side of the base of the second metacarpal bone. The radial 
artery as it dips down between the first and second metacarpal bones lies just to 
its outer side. Crossing under the tendon of the extensor longus pollicis is the 
extensor carpi radialis brevior, which proceeds to the top of the second interosseous 
space to insert into the adjoining sides of the second and third metacarpal bones. 

In the chink between the radius and ulna lies the tendon of the extensor 
minimi digiti. Between this tendon and the radial tubercle are the four tendons of the 



342 



APPLIED ANATOMY. 



extensor communis digitorum and extensor indicis muscles. Passing over the head 
of the ulna to insert into the base of the fifth metacarpal bone is the tendon of the 
extensor carpi ulnaris. It is best felt just beyond the extremity of the ulna when the 
hand is drawn toward the ulnar side. It inserts into the base of the fifth metacarpal 
bone. 

Compound Ganglion. — Large effusions into the sheath of the fiexor tendons 
of the wrist, usually purulent or tuberculous in character, sometimes cause two swell- 



.'^ 




Fig. 352. — Compound ganglion showing swellings above and below the anterior annular ligament. (From author's 

sketch of a tuberculous case.) 

ings, one in the palm of the hand and the other above the wrist. These commu- 
nicate beneath the anterior annular ligament and form what is called a compound 
ganglion (Fig. 352). 

FRACTURES OF THE LOWER END OF THE RADIUS AND ULNA. 

The lower end of the ulna is rarely fractured, but that of the radius vies with 
fracture of the clavicle in being the most frequent of all fractures. 




I 



Fig. 3 S3. — Colles's fracture of the lower end of the radius, showing the " silver fork deformity" and displacement 

of the fragments. 

Colles's Fracture. 

Fractures of the radius which occur at the wrist possess certain distinct charac- 
teristics and were for a long time confounded with dislocations of the wrist. These 
fractures are generally grouped by modern surgeons under the name of Colics' s 
fracture. This fracture was first correctly described, according to both Hamilton 
and Stimson, by Pouteau ("CEuvres Posthumes," t. 11, p. 251, 1783; also Nelaton, 
" Chirurgie Path.," t. i, p. 739). Mr. Colles, a Dublin surgeon, described the 
injury most carefully in the Edinburgh Medical and Surgical Jouryial, April, 18 14, 
but it is largely due to Robt. W. Smith's "Treatise on Fractures in the Vicinity 



REGION OF THE WRIST. 343 

of Joints," Dublin, 1847, that the name CoUes's fracture has become generally 
accepted. Mr. CoUes placed the injury i]4 inches (about 4 cm.) above the joint. 
Mr. Smith placed it from }^ in. to i in. (6 to 25 mm.) above the joint. Most recent 
waiters include all fractures within 4 cm. ( I ^ in. ) of the lower edge of the radius 
under this name, though some few go still higher. When the line of fracture lies 
more than 4 cm. above the joint it loses the characteristics of a Colics' s fracture and 
partakes of those of fractures of the shaft ; hence we will not go beyond that limit. 

The line of fracture is most commonly found, as stated by Robt. W. Smith, 
from 6 to 25 mm. (^ to i in.) above the joint. It passes almost transversely 
across the bone or inclines slightly downward to the ulnar side. It also lies nearer 
the joint on the anterior surface and inclines backward and upward toward the elbow. 
Hence the direction is from above downward and forward (Fig. 353). 

It is produced while the hand is extended (dorsally flexed) either by direct 
transmission of the force from the palmar surface of the wrist or by tension of the 
anterior radiocarpal ligament. 

The lower fragment is displaced upward and backward on the shaft of the 
radius. This causes it to be tilted backward so that the articular surface is rotated 
on a transverse axis more in the direction of the dorsum than normal and the hand is 
also carried toward the radial side. The dorsal displacement is due to the direction 
of the violence and not to muscular action. The radial side of the fragment is 
displaced upward more than the ulnar because the triangular fibrocartilage retains its 



cy^ 




Fig. 354. — Colles's fracture of the radius, showing inclination of hand toward the radial side and prominence of 
the styloid process of the ulna. (From author's sketch.) 

radio-ulnar attachments. This prevents the ulnar side from rising, while the radial 
side is pulled up by the radial flexor and extensor muscles. If the fracture is not 
extremely close to the joint the brachioradialis will pull the lower fragment toward 
the radial side and up toward the elbow. 

As the hand is attached to the radius it follows the lower fragment ; the extensor 
muscles of the thumb, the flexor carpi radialis, and the two extensor carpi radialis 
muscles all tend to aid the brachioradialis in producing the displacement toward 
the radial side (Fig. 354). 

The lower fragment is displaced toward the dorsum and the upper fragment 
toward the palmar surface. This produces the ' ' silver fork deformity' ' of 
Velpeau. This dorsal projection is sometimes increased by the presence of the 
"carpal tumor," a swelling due to effusion almost directly above the joint. The 
projection of the upper fragment toward the palmar surface and the effusion in the 
sheaths of the flexor tendons cause a protrusion on the anterior surface of the wrist 
and a marked increase in the lower anterior radiocarpal crease. 

To reduce the deformity the upper fragment is firmly grasped with one hand 
while with the other the hand of the patient is forcibly adducted (toward the ulnar 
side) and then sharply flexed. This drags the distal fragment down and forward off 
of the proximal one. To retain the fragments in position some surgeons use a pistol- 
shaped splint to hold the hand turned toward the ulnar side and place a graduated 
compress on the palmar surface with its base opposite the line of fracture and its 
apex upward and another pad on the dorsal surface with its apex downward over the 
hand. Other surgeons place the hand in a flexed position, allowing it to hang. 



344 



APPLIED ANATOMY. 



Separation of the Lower Epiphysis of the Radius, 

The lower radial epiphysis fuses with the shaft at about the twentieth year ; 
therefore epiphyseal separation can occur up to that time. The epiphyseal line 

passes across the bone from the base of the styloid process 
to the upper edge of the radio-ulnar joint (Fig. 355). 

The displacement, symptoms and treatment are the same 
as in CoUes's fracture and it is quite possible that many cases 
diagnosed as Colles's fracture may be epiphyseal separations. 

Fracture of the Lower End of the Radius with 
Displacement Forward. 

This fracture, though rare, occasionally occurs, and if 
union has taken place the deformity is marked and the 
injury is liable to be diagnosed as a luxation. It has been 
particularly described by Dr. John B. Roberts ("A Clinical, 
Pathological, and Experimental Study of Fracture of the 
Lower End of the Radius with Displacement of the Carpal 
Fragment toward the Flexor or Anterior Surface of the 
Wrist, ' ' Phila. , 1 897 ) . On account of the difificulties in diag- 
nosis it is well to examine its anatomical peculiarities. 

Displacement. — The lower fragment is tilted forward 
toward the palmar surface of the wrist, carrying the radial 
side of the hand with it (Fig. 356). 

Signs. — The line of the radius can be followed and 
felt to curve at its lower portion toward the palmar surface. 
The hand descending with the displaced fragment causes a 
groove to appear across the dorsum from one styloid process to the other. The 
dorsal surface of the lower part of the forearm is on a higher plane than that of the 
carpus. As the hand is lower than normal this causes the lower end of the ulna to 




Fig. 355. — Epiphyses of the 
lower ends of the radius and 
ulna; union occurs with the 
shaft of the bones at about the 
20th year. 




Fig . 3 s 6 . — Fracture of the lower end of the radius with displacement of the lower fragment toward the palmar 
surface. (Sketch, by the author, of a specimen in the Mutter Museum of the Philadelphia College of Physicians.) 

project much higher than it should. On account of the tension of the extensor carpi 
radialis longior and brevior the hand is held level with the forearm and does not 
droop as in Colles's fracture. Displacement to the radial side may or may not be 
marked. 

Fracture of the Lower end of the Ulna. 

Previous to the use of the X-rays for diagnostic purposes, fracture of the lower 
end of the ulna was considered extremely rare. Fractures of the ulna above the 
head resemble practically those of the shaft. 

Fracture of the styloid process was observed by D. H. Agnew in one case which 
was followed by deformity. Inasmuch as the deep fascia slides over the ulna it 
is readily seen that if it is perforated one or other of the fragments may be caught in 
the rent. This is probably the explanation of the deformity which occurred in 
Agnew' s case. He advised treatment with the hand bent toward the ulnar side to 
relax the extensor carpi ulnaris tendon. Fracture of the styloid process of the ulna 
has been shown by the X-rays to be a more frequent accompaniment of Colles's 
fracture than was formerly thought to be the case, — it tends to favor displacement 
of the hand toward the radial side. 



RECxION OF THE WRIST. 



345 



DISLOCATIONS AT THE WRIST. 

The dislocations at the wrist may be due to traumatism or may occur spontane- 
ously. There may be either a displacement of the carpus at the radiocarpal joint 
or of the ulna at the inferior radio-ulnar articulation. These luxations are very rare. 



DISLOCATIONS AT THE RADIOCARPAL JOINT. 

It is to Dupuytren that we owe the recognition of the fact that what were 
previously regarded as luxations of the wrist were really cases of fracture, usually 
of the radius. True luxations are exceedingly rare ; they may be either backward 
or forward an