MEMCAL SCHOOL

Gift of
Mrs. E.M. Lartigau

MANUAL OF SURGICAL ANATOMY

A MANUAL

OF

SURGICAL ANATOMY

BY

LEWIS BEESLY, F.R.C.S., EDIN.

ASSISTANT SURGEON, CHALMERS* HOSPITAL, EDINBURGH 5 LECTURER ON
SURGERY AND OPERATIVE SURGERY, EDINBURGH SCHOOL OF MEDICINE FOR
WOMEN J LECTURER ON SURGICAL APPLIED ANATOMY, EDINBURGH POST-
GRADUATE COURSES 5 EXAMINER IN ANATOMY, ROYAL COLLEGE OF SURGEONS,
EDINBURGH; LATELY DEMONSTRATOR OF ANATOMY, EDINBURGH UNIVERSITY

AND

T. B. JOHNSTON, M.B., Ch.B.

LECTURER AND DEMONSTRATOR OF ANATOMY, UNIVERSITY COLLEGE, LONDON ;

LATELY LECTURER AND DEMONSTRATOR OF ANATOMY, EDINBURGH UNIVERSITY,

AND LECTURER ON MEDICAL APPLIED ANATOMY, EDINBURGH POST-GRADUATE

COURSES

NEW YORK

WILLIAM WOOD AND COMPANY
1916

Printed in Great Britain by R. S: R. CLARK, LIMITED, Edinburgh.

PREFACE.

THE production of a new book on Surgical Anatomy calls for
a word of explanation. For some years past, while acting as
Demonstrators of Anatomy in the University of Edinburgh, we
have been struck by the fact that senior students and graduates,
when working in the dissecting room, seldom make use of any
of the numerous excellent works on Surgical Anatomy. They
seem to prefer standard books on Regional Anatomy ; and
while they assimilate the anatomical facts, they frequently
fail to appreciate their surgical application. Recognising that,
when possible, Surgical Anatomy should be studied from dis-
sections, we have endeavoured to present the subject in a form
suitable for use in the dissecting room. The general framework
of this book is founded on a series of lectures on Surgical Anatomy
delivered by one of the authors in connection with the Edinburgh
Post-Graduate Course.

While it has been found impossible to avoid encroaching
on the subject of Operative Surgery, an endeavour has been
made to bring into prominence the anatomy of the operations,
excluding as far as possible the details of surgical technique.
In order to keep the size of the volume within bounds, it has
been found necessary to omit, almost entirely, the descriptions
of amputations of the limbs.

On account of the frequency with which tuberculous disease
of bones and joints starts in, and spreads from, the ends of the
diaphyses (metaphyses), special attention has been given to
the anatomical relations which these regions and the adjacent
epiphyses bear to the capsules and synovial reflections of the
corresponding joints ; and in order to emphasise the importance
of these relations, we have included a number of figures in which
they are illustrated.

R2333

The published works of numerous authors have been con-
sulted from time to time, and we would specially acknowledge
our indebtedness to the writings of Mackenzie and Sherren, to
whom reference is frequently made in the different sections.

To Mr. Harold Stiles, whose teaching has formed the in-
spiration of this book, we desire to express our sincere thanks
for the valuable advice and suggestions with which he has so
frequently helped us. As one of the authors has had the
privilege of being associated with Mr. Stiles for some years, our
debt to him is even greater than is indicated by the frequent
recurrence of his name in the text.

We also desire to offer our warmest thanks to Professor
Robinson, who, in addition to having placed much of his material
at our disposal for the purposes of illustration, has frequently
given us the benefit of his criticism and advice. We are also
indebted to Dr. E. B. Jamieson, whose counsel on the subject
of nomenclature and on points of anatomical detail was often
sought ; and to Mr. R. J. M. Home, who gave us much help
while the volume was passing through the press.

The radiograms, except when otherwise acknowledged,
are the work of Dr. Edmund Price, whose kindness we highly
appreciate. We also desire to thank our publishers for allowing
us to reproduce many of the excellent illustrations in Cunning-
ham's Textbook of Anatomy and in Cunningham's Manual of
Practical Anatomy. The numerous new illustrations and
diagrams have been drawn for us by Mr. J. T. Murray, to whom
we are greatly indebted for the skill and care which he has
expended upon them.

L. B.
T. B. J.

EDINBURGH, 1915.'

CONTENTS.

SECTION I.— THE SUPERIOR EXTREMITY.

PAGE

THE SHOULDER REGION ... i

THE BREAST AND AXILLA . . 24

THE REGION OF THE (UPPER) ARM ... 38
THE REGION OF THE ELBOW . . .44

THE FOREARM AND WRIST . . 65

THE HAND ....... 80

THE BRACHIAL PLEXUS AND ITS BRANCHES . . 95

SECTION II.— THE HEAD AND NECK.

THE NECK . . . . . . . 107

THE FACE, MOUTH, AND PHARYNX . . .170

THE NOSE AND AIR SINUSES .... 194

THE EYE ..... .203

THE AUDITORY APPARATUS .... 209

THE HEAD . . . . . . . 218

THE BRAIN AND ITS MENINGES . . . 223

SECTION III.— THE ABDOMEN AND PELVIS.

THE ABDOMINAL WALLS . . . . .237

THE ABDOMINAL CAVITY ..... 276

THE PELVIS ....... 355

vii

PAGE

THE PERINEUM ...... 373

THE FEMALE PELVIS ..... 387

SECTION IV.— THE INFERIOR EXTREMITY.

THE FRONT OF THE THIGH .... 398

THE GLUTEAL REGION . . . . .413

THE HIP JOINT .... . 419

THE REGION OF THE KNEE . . . .441

THE LEG ....... 468

THE REGION OF THE ANKLE AND FOOT . . 477

THE NERVES OF THE LOWER LIMB . . . 499

SECTION V.— THE THORAX AND VERTEBRAL
COLUMN.

THE THORACIC WALL ..... 502
THE THORACIC CONTENTS ..... 505
THE POSTERIOR THORACIC WALL . . .513

THE VERTEBRAL COLUMN . . . . .516

THE SPINAL MEDULLA . . . . .524

INDEX . . . . . -539

LIST OF ILLUSTRATIONS.

FIG. PAGE

1. Surface landmarks of the shoulder region . . 3

2. The nerve-supply of the skin on the ventral aspect

of the trunk ..... 5

3. The nerve-supply of the skin on the dorsal aspect

of the trunk ..... 7

4. The sterno-clavicular joints .... 8

5. Shoulder of child, aged six. (Radiogram) . 16

6. Frontal section through the right shoulder-joint . 17

7. Sub-coracoid dislocation of shoulder- j oint. (Radio-

gram) ...... 21

8. The connections of the pectoral lymphatic plexus 27

9. Diagram of a section through the anterior wall of

the axilla ...... 30

10. The axilla and its lymph glands ... 36

11. The back of the arm ..... 40

12. The superficial nerves and veins on the front of the

upper limb ... . . . .46

13. The superficial nerves on the dorsal aspect of the

upper limb ...... 47

14. Schematic representation of the distribution of the

spinal nerves to the skin on the anterior aspect

of the upper limb ..... 48

15. Schematic representation of the distribution of the

spinal nerves to the skin on the dorsal aspect of

the upper limb ..... 49

1 6. Normal elbow of an adult female. (Radiogram) . 52

17. Frontal section through the elbow and proximal

radio-ulnar joints . . . . -53

1 8. Sagittal section through the elbow- joint . . 54

19. Elbow of child, aged four. (Radiogram) . . 55

20. Elbow-joint of boy, aged fourteen. (Radiogram) 56

21. Elbow-joint of child, aged five. (Radiogram) . 57

ix

C .Lib! U.P

FIG. PAGE

22. Elbow-joint of child, aged five. (Radiogram) . 59

23. Elbow-joint of adult, showing fracture of olecranon

(Radiogram) ..... 64

24. Surface landmarks on the dorsal aspect of the

superior extremity . . . . .67

25. The anterior aspect of the forearm . . 70

26. The muscles on the dorsal aspect of the forearm . 74

27. Section through the carpus, to show the various

joint cavities ..... 76

28. Carpus of an adolescent, aged sixteen. (Radio-

gram) ...... 78

29. Longitudinal section through the third finger . 83

30. The positions of the vessels and nerves relative to

the bones of the hand and wrist . . 85

31. Diagram of a transverse section through the

carpus, to show the arrangement of the synovial
sheaths . ..... 87

32. The synovial sheaths of the wrist and hand . 89

33. The hand of a child, aged three, showing tuber-

culous dactylitis. (Radiogram) ... 94

34. Diagram of the brachial plexus ... 96

35. Superficial nerves and veins of the neck . .109

36. Transverse section through neck, at level of seventh

cervical vertebra . . . . .112

37. Transverse section through neck, at level of third

cervical vertebra . . . . .113

38. The veins and lymph glands of the neck . . 118

39. The side of the neck . . . . .123

40. Diagram of the sympathetic trunk in the neck . 124

41. Bilateral cervical ribs. (Radiogram) . .128

42. The veins and lymph glands of the neck . . 133

43. Exposure of the posterior rami of the upper cervical

nerves ...... 137

44. The deep triangle of the neck . . .140

45. Frontal section through the mouth . .146

46. Scheme showing the branchial pouches, clefts and

arches and some of their derivatives . . 150

47. Surgical approach for the removal of advanced

malignant disease of the tongue . . . 153

48. Upper aperture of the larynx . . .156

49. The larynx as seen in the living subject by means

of the laryngoscope . . . .158

50. Median section through head and neck . .160

51. The anterior median line of the neck . .165

52. The nerves of the face . . . .173

ur

FIG. PAGE

53. Section through the mandibular joint . .179

54. Varieties of alveolar abscess . . .185

55. The development of the face . . . 191

56. Frontal section through the face of a human

embryo at the seventh week . . .192

57. Radiogram of skull, showing normal maxillary and

frontal sinuses . . . . .196

58. Empyaema of maxillary sinus. (Radiogram) . 197

59. Empyaema of left frontal sinus. (Radiogram) . 201

60. Lateral radiogram of skull . . . .202

61. Diagram of a sagittal section through the eye . 203

62. Diagram of the naso-lacrimal duct and its con-

nections ...... 205

63. Frontal section through the orbit . . . 207

64. Left tympanic membrane (as viewed from the

external acoustic meatus) . . . .212

65. Section of a left temporal bone along the line of the

tegmen tympani . . . . .213

66. Dissection of the tympanic antrum from the

lateral side . . . . . .217

67. Frontal section through the scalp, cranium,

meninges, and cortex cerebri . . . 220

68. Oblique section through the posterior part of the

skull, showing the relationship of the dura mater

to the cerebral sinuses . . . .224

69. Median section through the brain . . . 226

70. Cranio-cerebral topography . . . .228

71. Surface landmarks of the anterior abdominal wall 238

72. The nerve-supply of the skin on the ventral aspect

of the trunk ..... 241

73. Diagram to illustrate the viscero - sensory and

viscero-motor reflexes .... 243

74. The muscles on the dorsal aspect of the trunk . 245

75. Diagram to illustrate the method of closing wounds

in the supra-umbilical part of the linea alba . 247

76. The lines of some of the common incisions in the

abdominal wall ..... 249

77. Sections in the long axis of the inguinal canal . 256

78. Diagrams to illustrate the different conditions of

the processus vaginalis .... 258

79. Diagram of interparietal interstitial inguinal hernia 260

80. Diagram of extraparietal interstitial inguinal

hernia ...... 261

81. Diagram of a transverse section through the

scrotum and testes 266

FIG.

82. Transverse section through the abdomen, showing

the spread of a perinephric abscess . .270

83. Transverse section through the abdomen below the

kidneys ...... 272

84. The position and posterior relations of the kidney 274

85. Sagittal section of abdomen, showing the arrange-

ment of the peritoneum . . . .278

86. Transverse section of abdomen, at the level of the

epiploic foramen (of Winslow) . . .280

87. Transverse section of abdomen, immediately below

the epiploic foramen . . . .281

88. The posterior wall of the infra-colic compartment 284

89. Schema of sagittal section of embryo after the

formation of the head and tail folds . . 287

90. Schema of a sagittal section through a human

embryo, after the rotation of the intestinal loop 288

91. Normal hypertonic stomach. (Radiogram) . 291

92. High position of the pylorus. (Radiogram) . 292

93. Radiogram of stomach, showing typical J outline 293

94. Stomach of a child. (Radiogram) . . . 295

95. The arteries and lymph glands of the stomach . 297

96. Exposure of the terminal part of the bile-duct . 305

97. Surface relations of the liver and stomach . 308

98. Diagrams to show the varying modes of termina-

tion of the bile-duct and the pancreatic duct . 316

99. Dissection to expose the spleen . . .320

100. A coil from the upper part of the jejunum . 323

101. A coil from the lower part of the ileum . . 324

102. Partial prolapse of the caecum. (Radiogram) . 326

103. Persistence of the vitello-intestinal duct . . 328

104. Diagrams illustrating the different peritoneal

relationships of the caecum and vermiform
process ...... 332

105. " Double-barrelled " colon. (Radiogram) . . 335

1 06. The arteries and lymph glands of the large in-

testine ...... 337

107. The posterior wall of the infra-colic compartment 342

1 08. Small calculus impacted in right ureter. (Radio-

gram) . -347

109. Calcareous mesenteric lymph gland. (Radiogram) 348
no. Calculus in the renal pelvis. (Radiogram) . 352
in. Basal aspect of the bladder .... 358

112. Vesical calculus. (Radiogram) . . . 360

113. Radiogram showing the lower abdominal and the

pelvic portions of the ureters . . .363

114. Diagram of the pelvic fascia . . .374

115. Median section through the male pelvis . -375

1 1 6. The segmental supply of the skin in the perineum 377

117. Median section through the female pelvis . . 388

1 1 8. The superficial nerves and veins on the anterior

aspect of the lower limb .... 399

119. The subinguinal lymph glands and the fossa ovalis 401

120. Sagittal section through the femoral canal . 403

121. The femoral trigone ..... 407

122. Transverse section through the thigh . . 412

123. The gluteal region . . . . .417

124. The cutaneous nerves on the posterior aspect of the

lower limb ...... 419

125. Oblique section through the right hip-joint . 422

126. Congenital dislocation of the hip-joint. (Radio-

gram) .... 429

127. Surface landmarks in the region of the knee . 442

128. The medial side of the knee . . . 444

129. Normal knee-joint of a child, aged four. Antero-

posterior view. (Radiogram) . . .450

130. Knee-joint of child, aged thirteen. Lateral view.

(Radiogram) . . . . .451

131. Sagittal section through the knee-joint . -453

132. Oblique section through the right knee-joint . 454

133. The menisci and their attachments . . 456

134. Diagrams to illustrate injuries of the medial

meniscus . . . . . -457

135. Complete exposure of the knee-joint . . 461

136. Genu valgum. (Radiogram) . . . 464

137. Diagram to illustrate how a fractured patella may

be wired, without interfering with the articular
surface ...... 467

138. The front of the leg and dorsum of foot . . 470

139. The lateral aspect of the ankle and foot . . 473

140. The bony landmarks on the lateral aspect of the

ankle and foot . . . . .478

141. The surface landmarks on the medial side of the

ankle and foot . . . . .479

142. Normal ankle-joint of a child, aged fourteen.

(Radiogram) ..... 480

143. Frontal section through the ankle-joint . . 482

144. Sagittal section of foot, showing some of the

articulations ..... 483

145. Normal ankle-joint. Lateral view. (Radiogram) 489

146. Avulsion fracture of the calcaneus. (Radiogram) 490

FIG. PAGE

147. Transverse section through the foot . 493

148. Diagram of the sacral plexus . . . 500

149. Diagram of a transverse section through the thorax 506

150. Surface relations of the lungs, heart, and pleural

sacs ....... 507

151. Surface relations of the right lung and pleural sac.

Lateral view . . . . .508

152. Transverse section through the thorax, fourth

thoracic vertebra . . . . .512

153. Transverse section through a typical costo-

vertebral joint . . . • . .513

154. Transverse section through the upper part of the

posterior mediastinum . . . .514

155. Transverse section through the superior media-

stinum . . . . . .515

156. Ossification of a vertebra . . . .516

157. Kyphosis, produced by tuberculous disease of

thoracic vertebrae. (Radiogram) . . 517

158. Pott's disease in thoracic region of a child. (Radio-

gram) ...... 518

159. Scheme of the distribution of a typical spinal nerve 521

1 60. The spinal medulla in situ . . . 525

161. Diagram of a transverse section through the spinal

medulla ...... 526

162. Unilateral rotatory dislocation of the fourth

cervical vertebra . . . . .528

163. Diagrammatic representation of the chief motor

and sensory tracts in the central nervous system 531

164. Diagram illustrating some of the congenital

anomalies of the vertebral column and spinal
medulla . 535

MANUAL

OF

SURGICAL ANATOMY.

THE SUPERIOR EXTREMITY.

THE SHOULDER REGION.

Surface Landmarks. — The Clavicle is the most important
surgical landmark in this region. Its axis is directed downwards,,
forwards., and medially in well - developed subjects, but in
poorly - developed individuals the bone assumes a horizontal
position. The skin, superficial fascia, and platysma are all
freely movable over its subcutaneous surface, and therefore
compound fracture is a rare injury.

The large sternal end of the clavicle forms a rounded
prominence immediately to the lateral side of the jugular
(supra-sternal) notch and the sternal head of the sterno-mastoid.
In its medial two-thirds the shaft is convex forwards and
laterally, and this convexity is often greatly exaggerated in
children with rickets. The lateral third is concave forwards,
and on its anterior border there is a tubercle, of varying size,
which is produced by the deltoid. The middle third forms
the upper boundary of the superficial infra-clavicular triangle,
which is not always a well-marked depression. Its distinctness
depends on the proximity and development of the other borders,
namely, the anterior margin of the deltoid and the upper margin
of the clavicular head of the pectoralis major. On deep pressure
in this triangle just below the clavicle, the pulsations of the
first part of the axillary artery may be felt, and the vessel can

1

2 THE SUPERIOR EXTREMITY

be compressed downwards, backwards, and medially against
the second rib.

The lateral border of the acromial end of the clavicle is
marked by a weak ridge directed from before backwards, i£
inches medial to the lateral border of the acromion. When
the acromio-clavicular ligaments are lax, it is possible to insinuate
the finger-nail between the articular surfaces of the joint. An
adventitious subcutaneous bursa is occasionally met with over
this region in those accustomed to carrying heavy weights
upon the shoulder.

The coracoid process of the scapula is not situated in the
superficial infra-clavicular triangle, but lies under cover of the
anterior border of the deltoid. It can be felt on direct backward
pressure one inch below the clavicle lateral to the junction of
its middle and lateral thirds.

The apex of the acromion is placed one quarter to half an inch
in front of the acromio-clavicular joint. Its lateral border
can be traced backwards for about two inches, till it joins the
inferior border of the scapular spine, which meets it at the
sharp acromial angle. When the upper arm is measured in
suspected fracture of the humerus, the acromial angle is utilised
instead of the acromion apex, the latter being more obscured
by the deltoid. The subcutaneous upper surface of the acromion
can be readily examined when the arm is supported in the
abducted position, although the medial border is overlapped
by the trapezius and the lateral by the deltoid.

The spine of the scapula can be traced medially and downwards
to its flattened root opposite the third thoracic spine.

The superior border and the medial (superior) angle of the
scapula are on a level with the second rib, but cannot be palpated
easily, since they are under cover of the trapezius and the
supra-spinatus. They can be examined if the upper fibres of
the trapezius are relaxed by carrying the patient's arm as far
as possible over the opposite shoulder.

The lower three-fourths of the vertebral border, the inferior
angle, which lies over the seventh rib or seventh intercostal
space, and the lower part of the axillary border, can all be
palpated, if the patient's forearm is carried behind his back so as
to relax the trapezius, the rhomboids, and the latissimus dorsi.

The anterior fold of the axilla is formed by the lower border
of the pectoralis major, which, at its medial attachment, follows
the line of the fifth rib. A line, drawn from the lower margin

THE SHOULDER REGION

of the sternal end of the. clavicle to the lower limit of the insertion
of this muscle, outlines the lower border of its clavicular head
and indicates the plane of separation usually adopted in removal
of the muscle in complete excision of the breast (Stiles).

Coracoid process
Acromio-clavicular joint

Acromion

Greater tubercle

FIG. i. — Surface Landmarks of the Shoulder Region.

The Deltoid, with its wide V-shaped origin from the anterior
border of the lateral part of the clavicle, the lateral border of
the acromion, and the lower border of the scapular spine and
its pointed insertion half-way down the lateral side of the
humerus, is a conspicuous landmark. It overlies the greater
tubercle (tuberosity), which is the most lateral bony point in
the body, and so gives the shoulder its smooth convex contour.

Direct injuries around the greater tubercle of the humerus

4 THE SUPERIOR EXTREMITY

are often very difficult to diagnose, owing to the depth of the
bone from the surface and to the bruising and effusion which
supervene. An increase in the antero-posterior diameter of
the greater tubercle can be determined by grasping that land-
mark between the fingers and thumb and comparing it with
the greater tubercle of the opposite side. It is very suggestive
of fracture in this part of the bone, but accurate diagnosis is
possible only by means of the X-rays.

The lesser tubercle (small tuberosity) of the humerus points
directly forwards and lies one inch lateral to the coracoid process
and on a slightly lower plane. It also lies under cover of the
deltoid. On deep pressure over them, the tubercles can be
felt to slip from under the finger, if the humerus is rotated
alternately medially and laterally. Immediately to the lateral
side of the lesser tubercle lies the intertubercular sulcus (bicipital
groove) containing the long tendon of the biceps. This groove
corresponds to the lower two-thirds of a line three inches long,
drawn from the tip of the acromion down the arm in the axis
of the humerus.

When the arm is by the side, the inferior margin of the
head of the humerus is easily palpated through the floor of the
axilla. As the arm is abducted, more of the head becomes
exposed to the examining finger, but it is less distinctly felt
owing to the tightening of the axillary fascia.

Superficial Nerves. — The skin of the shoulder region is
supplied in front by the descending branches of the cervical plexus
(C. 3 and 4).

The anterior and middle supra-clavicular branches (supra-
sternal and supra-clavicular) extend down on to the chest wall
as far as the second intercostal space, where they are overlapped
by branches from the second intercostal nerve. This fact
explains the constant level of the anterior line of anesthesia in
fracture dislocations occurring between the fifth cervical and
second thoracic vertebrae, and also the referred pain sometimes
felt over the clavicle in Pott's disease of the third, fourth, and
fifth cervical vertebrae. Occasionally the supra-clavicular nerves
are involved in callus following fracture of the clavicle and cause
persistent neuralgia, which may radiate over the same side of
the head and neck. The posterior supra-clavicular (supra-
acromial) branches extend down for a short distance over the
deltoid, overlapping the cutaneous branches of the axillary
(circumflex) nerve (Fig. 2).

FIG. 2. — The Nerve Supply of the Skin on the Ventral Aspect of the Trunk.
The whole of the area shown in the diagram is supplied by branches
from the anterior rami (primary divisions) of the spinal nerves.

G.A, Great auricular nerve; S.C, N. cutaneus colli ; S.CL, Supra-clavicular nerves;
ACK, Posterior ; ST, Middle ; CL, anterior ; T.2-I2, Lateral and anterior branches
of thoracic nerves; I.H, Ilio-hypogastric nerve; I.I, IHo-inguinal nerve; CIRC,
Cutaneous branch of axillary nerve ; L.I.C, Medial cutaneous nerve of the arm (O.T.
lesser internal cutaneous nerve); I.H, Intercosto-brachial ; I.C, Medial cutaneous
nerve of the forearm (O.T. internal cutaneous); M.S, Cutaneous branch of radial
nerve ; E.C, Lateral cutaneous nerves ; G.C, Lumbo-inguinal nerve ; M.C1 2, Inter-
mediate cutaneous nerves ; I.C1, Branch of medial cutaneous nerve ; P, Branches of
pudendal nerve ; S.Sc, Branches of posterior cutaneous nerve of the thigh.

On the other side a schematic representation is given of the areas supplied by the above
nerves, the numerals indicating the spinal origin of the branches of distribution to
each area.

6 THE SUPERIOR EXTREMITY

Referred pain occurs in the shoulder region in diaphragm-
atic pleurisy and, on the right side, in tropical abscess of
the liver and, more rarely, in pathological conditions of the
gall-bladder. The stimuli reach the fourth cervical segment
via the phrenic nerve (p. 242).

Anteriorly, as already mentioned, the skin is supplied entirely
by C. 3 and C. 4, but the skin of the corresponding area on the
dorsal aspect is supplied by the fourth to the sixth cervical and
the upper three thoracic nerves (Fig. 3). From this it will
be seen why, in fracture dislocations below the fourth cervical
vertebra, the line of anaesthesia is higher on the posterior than
on the anterior aspect of the body.

Below the shoulder, i.e. over the floor of the axilla, the skin
is supplied by the lateral cutaneous branches of the second
(intercosto-brachial, p. 32) and third intercostal nerves.

Superficial Veins. — The cephalic vein runs upwards in the
groove between the deltoid and the pectoralis major, and passes
backwards through the superficial infra-clavicular triangle to
join the axillary vein. It frequently communicates with the
external jugular by means of a small vein which crosses in
front of the clavicle (Fig. 35). This vessel becomes considerably
enlarged in those cases of excision of the breast in which a
portion of the axillary vein has been excised, as it offers an
efficient channel for the return of venous blood from the
upper limb.

Trapezius. — The origin of this muscle extends from the
occipital bone above to the lowest thoracic spine. The upper
fibres are attached to the posterior border of the clavicle in its
lateral half. They support the clavicle, and, through it, part
of the weight of the upper limb, and are supplied by the (spinal)
accessory nerve. When the nerve is injured, the shoulder on
the affected side falls to a lower level, as it has lost its muscular
support. The lower part of the muscle is inserted into the
medial border of the acromion and the upper border of the spine
of the scapula ; and it is supplied by the cervical plexus (C. 3
and 4). A bursa is situated between the muscle and the flattened
root of the scapular spine. When the whole muscle contracts,
the point of the shoulder is elevated — particularly by the upper
fibres — and it is owing to this movement that abduction of the
arm is possible beyond an angle of 90°.

Sterno-Clavicular Joint.— The line of the joint passes
from above downwards and laterally. The articular surface of

FIG. 3. The Nerve-Supply of the Skin on the Dorsal Aspect of the Trunk.

The dotted line indicates the limits of the area supplied by the posterior
ranii (primary divisions) on the left side of the body.

G.O. Greater occipital nerve.

ACK. Posterior supra-clavicular nerves.

CIRC. Cutaneous branches of axillary

E.G. Lateral cutaneous nerve of

thigh.
S.Sc. Posterior cutaneous nerve of

thigh.

THE SUPERIOR EXTREMITY

the clavicle, the more mobile bone, is larger than the sternal
facet, and, below, it comes into contact with the first costal
cartilage. A somewhat loose capsule, lined with synovial
membrane, is attached to the margins of the articular surfaces.
It is thickened in front and behind by the anterior and posterior
sterno-clavicular ligaments. Anteriorly, the sterno-clavicular
joint is covered by the sternal head of the sterno-mastoid, and,
posteriorly, it is in relation to the sterno-hyoid and the sterno-
thyreoid muscles.

Joint capsule
Joint cavity

Interarticular
ligament

Joint cavity

Anterior chondro-
sternal ligament

FIG. 4. — Sterno-Clavicular and Costo-Sternal Joints.

The joint is divided into a medial or inferior and a lateral
or superior compartment by a disc-shaped meniscus, which is
attached to the clavicle above, the first costal cartilage below,
and to the capsule in front and behind. When the arm is
hanging by the side the upper compartment is V-shaped, but
when the arm is raised the upper part of the disc is thrust
medially by the clavicle, and both compartments become slit-
like. The disc acts as a buffer between the clavicle and the
sternum and serves to diminish the results of indirect violence.

Two accessory ligaments strengthen the joint : (i) The

THE SHOULDER REGION 9

inter-clavicular ligament, which stretches from clavicle to clavicle
across the upper surface of the capsule and dips down in the
centre to become attached to the jugular (supra-sternal) notch ;
(2) The costo-davicular (rhomboid) ligament, which connects the
under surface of the sternal extremity of the clavicle to the
upper surface of the first costal cartilage.

Movements. — The sterno-clavicular joint acts as a hinge
for the clavicle, so that when the acromial end of the bone is
elevated or depressed, carried forwards or backwards, the
sternal end passes in the opposite direction. In elevation or
depression of the point of the shoulder the sternal end of the
clavicle moves over the surface of the articular disc, but when
the shoulder is thrust forwards or backwards the disc moves
with the clavicle over the clavicular facet on the sternum.
Excessive upward movement of the shoulder is checked by the
tension of the costo - clavicular ligament, and the opposite
movement by the tension of the articular disc and the inter-
clavicular ligament.

The anterior supra-clavicular (supra- sternal) nerves (C. 3 and 4)
supply the joint, and branches from the internal mammary and
the clavicular branch of the thoraco-acromial (thoracic axis) artery
anastomose around it.

In Dislocations of the Joint the sternal end of the clavicle
usually passes forwards, tearing the anterior sterno-clavicular
ligament. The direction taken by the bone is said to be due
to the weakness of this ligament, but it is more probable that it
depends on the application of the force along the axis of the
clavicle. Though this dislocation is easy to reduce by pulling
the two shoulders backwards, it is difficult to retain the bones
in apposition owing to the normal obliquity of their articular
surfaces.

Backward dislocation is rare, and is caused either by indirect force thrusting
the shoulder forwards, or by direct violence from in front at the sternal
end of the clavicle. In this injury the posterior sterno-clavicular ligament
is torn, and the clavicle passes backwards, downwards, and medially, and
may compress the innominate vein, the trachea, or on the left side, the
oesophagus.

Dislocation upwards is especially resisted by the articular disc and the
inter-clavicular ligaments. When these ligaments are torn, the sternal
end of the clavicle passes into the jugular (supra-sternal) notch between the
sterno-mastoid anteriorly (p. 8) and the sterno-hyoid and sterno-thyreoid
posteriorly.

The sterno-clavicular joint is not infrequently the seat of suppuration
in pyaemia. One or both compartments may be involved and the pus usually
perforates the anterior ligament. Should it perforate the posterior ligament,

io THE SUPERIOR EXTREMITY

it will find its way down between the two pleural sacs into the superior
mediastinum, following the course of the innominate vein.

On the right side, the joint may be involved in aneurism of the innominate
artery, which lies immediately behind it.

Acromio- Clavicular Joint.— The articular surfaces of
the two bones are oblique and the plane of the joint passes
downwards and medially. A weak capsule,, thickened above
and below, is attached to the articular margins. A wedge-
shaped disc protrudes into the joint cavity from the upper
part of the capsule ; the disc is covered and the capsule is lined
with synovial membrane. The joint is strengthened by the
accessory conoid and trapezoid bands, which together form the
coraco - clavicular ligament and bind the upper surface of
the coracoid process to the under surface of the clavicle near its
acrornial end. Part of the weight of the upper limb is conveyed
to the clavicle along this ligament.

The posterior supra-clavicular (supra-acromial) nerves (C. 3
and 4) and the acromial branch of the thoraco-acromial artery
(p. 30) supply the joint.

A gliding antero-posterior movement occurs at the acromio-
clavicular articulation, so that, when the shoulder is thrust
forwards, the angle between the clavicle and the upper border
of the spine of the scapula becomes smaller.

The obliquity of the articular surfaces serves to explain the
common injury of upward dislocation of the clavicle. Any force
directed medially or downwards on to the acromion will thrust
it beneath the clavicle, tearing the superior ligament of the
joint. The reverse dislocation is extremely rare. A much
exaggerated displacement in either dislocation indicates rupture
of the coraco-clavicular ligament.

The Clavicle fulfils the functions of a prop and keeps the
acromion, and, through it, the shoulder-joint at a constant
distance from the trunk, to which it transmits the weight of the
upper limb. The trapezius supports its acromial end and
counteracts the downward pull of the weight of the arm. The
clavicle is exposed more often to violence than any other bone
in the body and, for that reason, is very commonly injured.
These injuries may take the form of fractures, dislocations, or
separation of the epiphysis.

Ossification. — The clavicle is the first bone in the body to ossify (fifth
week), and the primary centre forms the shaft and the acromial end. A
secondary centre appears at the sternal end at about the twentieth year
and fuses with the shaft about the twenty-fifth. Congenital absence of both

THE SHOULDER REGION n

clavicles is rare, but from accounts of the recorded cases, the functional

disability is slight.

Excision of the Clavicle. — Removal of the Middle Third
of the clavicle is commonly carried out as a preliminary step
in interscapulo-thoracic amputation, as it facilitates ligature of
the third part of the subclavian artery. The Whole Bone
may be excised most easily from acromial to sternal end.

Examination of the Clavicle. — In suspected injury of the
clavicle or of the acromion, the surgeon stands behind the patient
and compares the contours of the two shoulders. He next
places a hand on each side of the neck in such a way that the
tips of the fingers palpate the jugular (supra-sternal) notch
and the thumbs rest behind on the vertebral spines. The hands
are separated from one another so that the fingers pass over the
subcutaneous surfaces of the two clavicles. When the acromio-
clavicular joint is reached the fingers are carried forwards around
the anterior extremity of the acromion, and its subcutaneous
surface and lateral border may be palpated.

Fractures of the Clavicle. — Fracture of the sternal end of
the clavicle, medial to the costo-clavicular (rhomboid) ligament,,
is rare, and the displacement is not great unless the costo-
clavicular ligament is torn. When this occurs, the medial
end of the lateral fragment is drawn upwards by the sterno-
mastoid and the acromial end of the clavicle sinks downwards
owing to the weight of the arm.

The common site of fracture is the point of union of the middle
and lateral thirds, where the bone is weak owing to the junction
of its two curves. It is the commonest of all fractures. One
third of the cases are of the greenstick variety and occur in
infancy. It is generally due to indirect violence from falls on
the hand, elbow, or shoulder, and the force is transmitted to
the clavicle through the glenoid cavity and the coraco-clavicular
ligament, or through the acromion. The direction of the
fracture is most constant — it is downwards, medially, and
forwards. The displacement of the lateral fragment is in the
same direction, and the limb collapses medially and forwards
on to the trunk, consequent on the snapping of its prop. The
medial fragment is drawn upwards by the sterno-mastoid. It
is rare to find any injury to the subclavian vessels or to the
nerves of the brachial plexus, which all lie behind and below
the clavicle, because they are protected by the subclavius
muscle, which acts as a cushion between them and the broken

12 THE SUPERIOR EXTREMITY

bone. Occasionally, the lateral fragment is displaced backwards
by direct violence from in front. In this case the transverse
scapular (supra-scapular) and transverse cervical (transversalis
colli) veins (p. 131) may be injured.

Fracture of the acromial end of the shaft may occur between
the attachments of the two parts of the coraco-clavicular
ligament from direct violence, in which case there is little
displacement,, or it may occur lateral to the ligament, in which
case the lateral fragment tends to turn medially and forwards.
The point of the shoulder is rotated medially and sinks slightly.

In children, fractures of the clavicle are usually of the
greenstick variety, as the bone is soft and its enveloping
periosteum is exceedingly strong.

The Vertebro-Scapular Muscles. — The Trapezius is described on
p. 6.

The Levalor Scapulce is attached to the medial (superior) angle of the
scapula, by elevating which it helps to depress the point of the shoulder.
It is supplied by C. 3 and 4 (p. 130).

The Rhomboid Minor and Major arise from the upper thoracic spines
and are inserted into the vertebral border of the scapula. They draw the
scapula medially, backwards and upwards. The dorsalis scapulae nerve
(nerve to the rhomboids) (C. 5) runs down along the vertebral border of the
scapula under cover of the three above-mentioned muscles. (The results of
injury to this nerve are described on p. 97.) It is accompanied by the
descending (posterior scapular) branch of the transverse cervical artery,
which anastomoses on the scapula with the subscapular (p. 34) and the
transverse scapular (supra-scapular) arteries (p. 143).

The Scapula. — Ossification begins in the fcetal scapula
during the second month. The most important secondary
centre forms the greater part of the coracoid process. It
appears during the first year and joins the body about the
eighteenth year. Cases of ununited coracoid epiphyses have
been recorded, but the condition is very rare.

Two secondary centres appear about the tenth year to form
the acromion,, and join the spine of the scapula about twenty-five.
This epiphysis fails to fuse in 10 per cent of subjects, and the
condition is usually bilateral. The line of non-union is transverse
and is at right angles to the axis of the acromio-clavicular joint.
The acromion is generally attached to the spine by fibrous
tissue, but occasionally a complete joint is present. The presence
of a movable acromion, together with a history of injury to
the shoulder region, is apt to suggest a fracture. The
symmetrical character of ununited acromial epiphysis is of
great value in the differential diagnosis.

THE SHOULDER REGION 13

A sub-coracoid centre,, which forms part of the base of the
coracoid and the upper part of the glenoid cavity, appears at
ten and fuses at seventeen. The margin of the glenoid cavity
inferiorly is formed by a secondary centre which appears at
seventeen and fuses soon after. The other secondary centres
have little surgical importance.

Fractures of the Scapula are uncommon because the bone
is well protected by muscles. The commonest variety is
fracture of the body, generally through the infra-spinous fossa.
The spine and coracoid process, which belong to the upper
fragment, may be gripped with one hand, and the inferior
angle, which belongs to the lower fragment, with the other.
Preternatural mobility and crepitus may be determined by
moving the hands in opposite directions.

If the surgical neck, which extends from the scapular notch
to a point on the axillary border just below the glenoid cavity,
is fractured, the surgeon can grasp the spine and acromion with
one hand and the head of the humerus with the other. Crepitus
may sometimes be elicited, through the medium of the capsule
of the shoulder-joint, by moving the head of the humerus
backwards and forwards.

Fracture of the Coracoid is rare, and up to seventeen may
l)e of the nature of a separation of the epiphysis. There is little
displacement, unless the coraco -clavicular ligament, which
holds it up, is torn. Laterally, the coracoid is steadied by the
coraco-acromial ligament, and medially, by the pectoralis minor.
It is drawn downwards by the weight of the arm and by the
coraco-brachialis and the short head of the biceps, which are
attached to its tip.

In complete excision of the scapula for malignant disease, a
preliminary ligature of the subscapular vessels and myotomy
of the muscles attached to the coracoid process may be performed
through an incision along the medial border of the coraco-
brachialis.

The Coraco-Acromial Ligament passes from the lateral
border of the coracoid process to the acromion just in front of
the acromio-clavicular joint. It forms a strong arch above
the shoulder-joint, and helps to prevent upward dislocation of
the head of the humerus.

The Sub-acromial Bursa lies between the deltoid, the
acromion and the coraco-acromial ligament above, and the
capsule of the shoulder-joint and the muscles attached to it

14 THE SUPERIOR EXTREMITY

below. It very rarely communicates with the joint, but owing
to its position, pathological conditions of the bursa may be
mistaken for articular affections. The sub-acromial bursa
serves as a soft pad between the humerus and the acromion,
but when it is distended with fluid or when the walls are
thickened by chronic inflammation (Codman's bursitis),
movements of the humerus become painful, especially the
movement of abduction, which crushes up the bursa against
the acromion. Pus from an abscess of this bursa gravitates
either to the anterior or to the posterior border of the deltoid.

The Deltoid (p. 3) continues and maintains the movement
of abduction of the humerus, after it has been initiated by the
supra-spinatus. In complete abduction the humerus can be
raised to an angle of nearly 180°, but the deltoid is responsible
for only half of that amount. The rest is effected by rotation
of the scapula under the action of the trapezius and the serratus
anterior (p. 31). The clavicular fibres are flexors and medial
rotators of the humerus ; the posterior fibres have the opposite
actions. The muscle overlies the shoulder- joint and the tendons
in relation to it, and is supplied by the axillary (circumflex)
nerve (C. 5 and 6), which enters its deep surface.

The Deep Fascia on the Dorsal Scapular Muscles. — The
deep fascia is strong and dense over the supra-spinatus and
infra-spinatus muscles, and is attached to the borders of the
scapular fossae. It is weakened above the superior transverse
scapular (supra-scapular) ligament, where the transverse scapular
vessels enter the fossa, and also at a point half-way down the
axillary border, where the circumflex scapular (dorsalis scapulae)
vessels pass on to the dorsum.

Pus originating in the infra-spinous fossa is prevented from
passing backwards by the strong fascia. It follows the circumflex
scapular (dorsalis scapulae) vessels and gravitates down to
point at the lower part of the posterior fold of the axilla. In
the supra-spinous fossa it generally passes through or over the
scapular (supra-scapular) notch and points, near the coracoid
process, under the anterior border of the deltoid ; or, it may
gravitate into the infra-spinous fossa : or, very rarely, it may
make its way through the supra-spinous fascia and the trapezius
and point in the angle between the clavicle and the spine of the
scapula.

The Supra-spinatus arises from the supra-spinous fossa, and is inserted
into the upper surface of the greater tubercle of the humerus. It passes

THE SHOULDER REGION 15

immediately above the shoulder-joint and is partly inserted into the capsule.
It initiates the movement of abduction and assists the deltoid.

The Infra-spinatus arises from the infra-spinous fossa, and is inserted
into the postero-superior surface of the greater tubercle. It passes over the
posterior surface of the shoulder-joint and partially blends with the capsule ;
it is the chief lateral rotator of the humerus.

Both these muscles are supplied by the supra-scapular nerve (C. 5 and 6),
which passes through the scapular notch below the ligament. (The results
of injury to this nerve are described on p. 98.)

The Teres minor lies in relation to the posterior aspect of the capsule
of the shoulder-joint, and its action is the same as that of the infra-spinatus.
It is supplied by the axillary (circumflex) nerve (C. 5 and 6).

Ossification of the Proximal Extremity of the Humerus.—

At birth the proximal extremity of the humerus is entirely
cartilaginous. During the first year a secondary centre appears
for the articular head of the bone ; at the second year, one
appears for the greater tubercle ; at the end of the third year,
one appears for the lesser tubercle. These three centres unite
to form the proximal epipbysis of the humerus during the
seventh year. It fits like a cap over the proximal end of the
diaphysis, which is somewhat pointed (Fig. 5), and it fuses
with the diaphysis between eighteen and twenty-five. The
epiphyseal line passes distal to the tubercles, but on the medial
side it coincides with the margin of the articular head of the bone.

Ossification of glenoid cavity (p. 13).

The Shoulder-Joint.— The articular surface of the glenoid
cavity is slightly concave and is small in comparison with the
head of the humerus, which forms a large convex surface,
directed upwards, medially, and slightly backwards. The
glenoid cavity is enlarged and deepened by the labrum glenoidale
(glenoid ligament), which is attached to its margins.

The Capsule, which is very large and remarkably loose,
obtains a wide range of movement for the joint. Proximally,
it is attached to the labrum glenoidale, and above, to the bone
immediately beyond the origin of the long head of the biceps.
On the humerus it is attached to the anatomical neck, laterally,
but to the surgical neck, on the medial side. The line of
attachment of the capsule crosses the epiphyseal line, so that
the lateral portion of the epiphysis (the tuber osities) is extra-capsutar ,
while the medial part of the proximal end of the diaphysis is
intra-capsular.

The capsule is strengthened anteriorly by the three gleno-
humeral ligaments, and above by the coraco-humeral ligament.
These accessory bands blend with the capsule so closely that

i6

THE SUPERIOR EXTREMITY

it is impossible to separate them from it. Additional support
is received from the subscapularis in front, the supra-spinatus
above, and the infra-spinatus, and to a lesser degree the teres

FIG. 5. — Shoulder of a Child, aged six. Antero-posterior view. The centre
of ossification for the greater tubercle has not yet fused with the centre
for the head of the humerus. The radiogram shows a fracture through
the surgical neck of the bone. Compare the position of the head of the
humerus with that shown in Fig. 7.

minor, behind. Inferiorly, the capsule pouches downwards
when the arm is by the side, an arrangement which permits of
free abduction. It is here intimately related to the quadrilateral

THE SHOULDER REGION

space (p. 39), and the structures passing through it (Fig. 6).
Stiffness of the shoulder, following reduction of dislocations,
may be due to the formation of adhesions between the contiguous
synovial surfaces of this part of the capsule. Early massage
and passive movement will prevent such a complication.

Capsule

Epiphyseal line

Sub-acromial bursa
Acromion
i Clavich

Tendon of bicep

Joint cavity

Synovial

sheath of

biceps

tendon

Proximal epi-
physis of
humerus
Labrum
glenoidale

_*f^^^ Epiphyseal line
(sub-coracoid)

Epiphyseal line
(glenoid)

Dependent part
of capsule
Axillary nerve

FIG. 6. — Frontal Section through the Right Shoulder-Joint. The parietal
and visceral layers of the synovial sheath of the biceps tendon have been
partially left in place.

Light blue = articular cartilage. Green — periosteum.

Dark blue = ligaments. Red — synovial membrane.

The Synovial Membrane lines the capsule and is attached
to the articular margins of the two bones. It covers, but is
not adherent to, the periosteum over the intra-capsular part,
of the neck of the humerus (intra-capsular part of diaphysis
and epiphyseal cartilage, in the young). Between the superior

2

1 8 THE SUPERIOR EXTREMITY

and middle gleno-humeral ligaments, there is an opening in the
capsule. The synovial membrane of the joint herniates through
this opening to form a bursa, which is situated between the
subscapularis in front and the neck of the scapula and the
capsule behind. A similar bursa, communicating with the
joint, may occasionally be found between the capsule and the
tendon of the infra-spinatus.

The long head of the biceps arises from the highest point on
the glenoid margin and traverses the joint. But although it
is intra-capsular, it remains extra-synovial as it receives a tubular
sheath from the synovial membrane (Fig. 6), which invests
the tendon for a varying distance after it has left the capsule.
This synovial sheath and the tendon are retained in the inter-
tubercular sulcus by the transverse ligament — a special slip
of the capsule, which bridges the groove and is attached to
both tubercles. This ligament is occasionally torn by violent
muscular efforts,, and when that occurs the tendon of the biceps
becomes displaced to the medial side of the lesser tubercle.
Until the tendon is replaced by the movement of abduction,,
the forearm cannot be completely extended (Thomson and
Miles).

The nerve-supply of the joint comes from the supra-scapular
and axillary (circumflex) nerves (C. 5 and 6).

Around the surgical neck of the humerus an arterial ring
is formed by the anterior and posterior circumflex arteries, which
send branches proximally to supply the joint. These anastomose
with twigs from the transverse scapular (supra-scapular), which
descend from above, and with an ascending branch from the
(superior) profunda (p. 43).

The presence of fluid within the joint may be appreciated
in the neighbourhood of the long head of the biceps, because
it gravitates down the synovial sheath which surrounds the
tendon. When the subscapularis bursa is involved, the swelling
may be felt high up on the posterior wall of the axilla. The
joint is best aspirated by pushing the needle backwards through
the deltoid and the subscapularis at a point a quarter of an inch
medial to the lesser tubercle, which serves as a convenient bony
landmark. In this way the great vessels and nerves and the
sub-acromial bursa are all avoided.

Spread ot Tuberculous Disease in the Shoulder Region.—
When tuberculous disease originates in the head or neck of the
scapula, it readily spreads to the joint through the articular

THE SHOULDER REGION 19

cartilage, because the epiphyseal cartilages of the secondary
centres for the glenoid cavity only exist near its margin (p. 13).

If the disease begins in the proximal end of the diaphysis of
the humerus and spreads either forwards, backwards, or laterally,
it will in time perforate the periosteum and infect the overlying
soft parts. Should it spread medially, it will perforate the
periosteum covering the intra-capsular part of the diaphysis
(Fig. 6). The infection will then be intra-capsular but extra-
synovial. The synovial membrane rapidly becomes involved
and the joint infected. If the disease spreads upwards, it must
involve the epiphyseal cartilage and epiphysis before it can
break through the articular cartilage into the joint. Lastly,
it may travel distally and infect the medullary cavity.

Surgical Approach to the Shoulder- Joint. — In Empycema
of the joint, good access is obtained by a vertical incision,
made midway between the coracoid process and the acromion.
The anterior fibres of the deltoid are divided and the dis-
tended capsule, which is then exposed, can be incised. A
pair of dressing forceps may be passed through the joint and
made to project posteriorly below the tendon of the teres
minor. The instrument may then be cut down upon from
behind and a drainage tube drawn through.

In Tuberculous Disease, the joint may be approached either
from the anterior or from the posterior aspect. The latter
route, though more difficult, gives the better access (Kocher).
In the anterior method the approach is direct, and little damage
is done either to the deltoid or to its nerve of supply. By
rotating the humerus first medially and then laterally, it is
possible to elevate the muscles from the greater and lesser
tubercles, either sub-periosteally or sub-cortically, depending
on the age of the patient. The head of the humerus may be
removed through a comparatively small incision, but if the
glenoid cavity and neck of the scapula require to be excised,
some difficulty will be found in removing them by the anterior
method of approach.

The posterior method of approach affords a much more
extensive view of the articulation. This is obtained by freeing
the trapezius and the deltoid from the spine of the scapula, by
sawing through the spine obliquely into the great scapular
notch, and by rotating forwards the acromion and the deltoid.
The capsule is opened above, where, according to Kocher, the
subsequent weakness matters least.

20 THE SUPERIOR EXTREMITY

Dislocation of the Shoulder.— In the child, the capsule
is stronger than the bond of union between the diaphysis and
epiphysis, and consequently the common injury is a separation
of the proximal epiphysis. In the adult, the shoulder-joint is
ligamentously and osseously weak, and is strong only by virtue
of its muscular support. Stability is sacrificed to the necessity
for mobility, and, as a result, dislocation of the joint is exceedingly
common.

The violence which causes the dislocation is unexpected,
and the supporting muscles are consequently relaxed at the
time of the accident. The humerus is generally in the abducted
position and forms the long arm of a lever, whose short arm is
formed by the head of the bone. The acromion acts as a fulcrum,
and when the long arm of the lever is thrust upwards, the head
is tilted downwards upon the inferior part of the capsule, which
is the only area unsupported by muscular insertions. This
gives way, and the head of the bone passes through the tear
and lies below the glenoid cavity.

The head may remain in this position — the sub-glenoid
dislocation. The lower margin of the glenoid rests in the groove
of the anatomical neck, and the head lies between the long head
of the triceps behind and the subscapularis in front.

Though all dislocations are, in the first instance, sub-glenoid,
the flexors and adductors of the shoulder usually draw the head
of the humerus upwards, forwards, and medially. This is the
anterior displacement, and the head of the bone may occupy
any of the following positions :

1. The Sub-coracoid. — This is the commonest dislocation.
The posterior part of the anatomical neck rests against the
anterior margin of the glenoid cavity, and the head lies behind
the subscapularis. The articular surface is directed somewhat
forwards, and the humerus is laterally rotated owing to the
stretching of the infra-spinatus and the teres minor. The
posterior part of the capsule is stretched across the articular
surface of the glenoid cavity.

2. The Intra-coracoid. — In this dislocation the anatomical
neck rests on the anterior surface of the neck of the scapula.
The lateral rotators are over-stretched, and if they do not rup-
ture, a part or the whole of the greater tubercle is torn away,
and the subscapularis, being unopposed, rotates the humerus
medially.

3. The Sub-clavicular. — The head of the humerus rests

THE SHOULDER REGION

21

on the subscapular fossa, and it can reach this position only
after extensive laceration of the capsule and the muscles.

FIG. 7. — Sub-coracoid dislocation of Shoulder- Joint in an Adult Female.
Owing to the displacement the acromion projects beyond the greater
tubercle, while the shadows thrown by the glenoid fossa and the upper
part of the axillary border of the scapula are partially obscured by the
head of the humerus, above which the foreshortened coracoid process
can be recognised.

In the Posterior Displacements the head of the humerus

22 THE SUPERIOR EXTREMITY

rests on the posterior margin of the glenoid cavity, or on the
neck of the scapula, or in the infra-spinous fossa. The
infra-spinatus is usually stripped up by the head of the bone,
and the nature of the rotation of the humerus depends on
whether the subscapularis is ruptured or remains intact.

In all dislocations of the shoulder the normal rounded contour
is lost, as the greater tubercle is drawn medially. For the
same reason the lateral border of the acromion, now the most
lateral bony point in the region, becomes more prominent, and a
straight edge can be made to touch both the acromion and the
lateral epicondyle of the humerus. In the anterior displacements
the head of the humerus produces a rounded elevation, which
may occlude the superficial infra-clavicular triangle. This
deformity is more pronounced in the sub-clavicular variety.

Miller's Method of Reduction. — The initial steps, which
consist of abduction and traction on the arm, draw the head
of the humerus free from the scapula, relax the deltoid and
supra-spinatus, and stretch the lower part of the capsule and
the subscapularis. If the tear involves the anterior part of
the ligament, reduction may occur without further manipulation,
as in Kocher's method (vide infra). If the tear is confined to
the inferior aspect of the capsule, the articular head of the
humerus is brought into contact with it by the next step —
medial rotation. Owing to the continued traction the tendon
of the subscapularis is tightly stretched over the head, which it
presses through the gap when the traction is lessened. In this
method an assistant steadies the patient's chest and scapula
throughout, thus exerting counter-extension.

Kocher's Method of Reduction. — In the first instance the
patient's elbow is pressed firmly against his side in order to
fix the distal end of the humerus, as only by this means can
subsequent manipulations exert their full action on the head
of the bone. Grasping the patient's wrist with his free hand,
the surgeon uses the forearm as a lever to produce lateral
rotation of the humerus. This is effected by carrying the fore-
arm away from the body till it is nearly in the frontal (coronal)
plane, and the movement is performed slowly and steadily in
order to overcome the muscular spasm. In this way the
anatomical neck is disengaged from the glenoid margin, and
the posterior aspect of the greater tubercle comes into contact
with the articular surface of the glenoid cavity, from which it is
separated by a part of the capsule.

THE SHOULDER REGION 23

The articular head now looks directly forwards, and if the
tear has spread to the anterior aspect of the capsule, the tendon
of the subscapularis, rendered tense by the excessive lateral
rotation, may press the bone back into place.

If reduction does not occur at this stage, the elbow is carried
forwards and medially, lateral rotation of the humerus being
maintained through the position of the forearm. This move-
ment of flexion and adduction stretches the capsule by tilting
the greater tubercle backwards, and at this stage the head
often passes back into place. Should it not do so, the patient's
forearm is rapidly swung over towards the opposite shoulder
to produce medial rotation of the humerus. If the elbow is
elevated slightly during this movement, the head of the humerus
descends, as it rotates medially, and passes through the torn
inferior part of the capsule.

In testing passive movements or the limitations of movements
following injury in the region of the right shoulder- joint, the
surgeon stands behind the patient and holds the semi-flexed
elbow of the affected side in his own right palm. This enables
him to move the humerus at the shoulder- joint in any way he
desires, while the left hand examines the injured region. The
left shoulder is examined with the positiont>f the hands reversed.

Complications. — Dislocation of the shoulder may be
complicated by the tearing off of a part of the greater tubercle.
If the fragment includes the insertion of the supra-spinatus, it
is drawn upwards and subsequently limits abduction by becoming
jammed beneath the acromion.

Fracture through the anatomical or surgical neck is a rare
but important complication. The head of the humerus can be
palpated through the superficial infra-clavicular triangle or
beneath the coracoid process ; but the diagnosis of the fracture
will be determined if movement of the humeral shaft produces
no effect on the head. Owing to the small size of the proximal
fragment manipulative methods of reduction rarely succeed,
and operative measures usually have to be adopted, the joint
being approached from in front (p. 19).

Injuries to the brachial nerves following dislocation of the
shoulder are described on pp. 98-101.

Attempts to reduce old-standing dislocations of the shoulder
may cause rupture of the axillary artery and stretching or
laceration of the brachial plexus, owing to the presence of
adhesions between the head of the humerus and the axillary

24 THE SUPERIOR EXTREMITY

sheath. In these cases the lateral rotation carried out in
Kocher's method of reduction exerts a powerful twisting or
spiral strain upon the bone and; if the adhesions are strong,
the humerus may be fractured spirally at the surgical neck.
In the old-fashioned method of reduction by means of the heel
in the axilla, the extending force is exerted along the long axis
of the shaft of the humerus, and there is therefore no danger of
spiral fracture. On the other hand, the upper ribs may be
fractured, unless the pressure of the heel is directed towards
the coracoid process and not against the chest wall.

Congenital Elevation of the Shoulder. — At an early period of
development, the scapula and clavicle occupy positions much nearer the head
end of the embryo than they do at birth, and as the scapula grows in size
it migrates caudally. Incomplete caudal migration of the scapula accounts
for the condition of congenital elevation of the shoulder described by Eulen-
burgh and Sprengel. It may be due to the presence of a bridge of bone
joining the vertebral border of the scapula to the lower cervical spines.
This bridge of bone, which may possess a false joint at either end, is homo-
logous with the cartilaginous supra-scapula found in some lower mammals.

The upper border and medial (superior) angle of the scapula lie consider-
ably above the head of the first rib, and may be mistaken for an exostosis.
The muscles which elevate the scapula are all definitely shortened, and the
skin is drawn up into a fold, which extends from the mastoid process to the
acromion. The condition may be bilateral and is associated with cervical
ribs, or with faulty ossification of the cervical vertebrae, which may be fused
together leading to restriction of movement.

THE BREAST AND AXILLA

Development of the Mammary Gland.— The connective
tissue of the mamma is mesodermal in origin, while the
glandular tissue which infiltrates it is derived from the ectoderm.
During the second month of embryonic life a distinct thickening
of the ectoderm forms the mammary ridge, which extends from
the axilla to the groin. Normally the thickening is limited
to that part of the ridge which subsequently overlies the thorax,
but occasionally it is not so limited, and then supernumerary
nipples or breasts may appear.

During the third month the ectodermal nodule becomes
depressed or invaginated into the underlying connective tissue
so that a small pit is formed. In the fifth month solid ectodermal
buds, from fifteen to twenty in number, grow inwards, and
their stalks subsequently give rise to the epithelial lining of the

THE BREAST. AND AXILLA 25

lactiferous ducts. Extensive changes occur during the seventh
and the ninth months. The lobes derived from the ectodermal
buds subdivide to form lobules, which, at their growing ends,
invade the surrounding connective tissue and fat, thus breaking
up the mesodermal stroma into the interlobular septa and
fibrous framework of the corpus mammae. At the same time
the whole ectodermal mass becomes canaliculised and gives
rise to a system of ducts and alveoli, while the depressed area
becomes evaginated on the surface to form the nipple. During
the latter part of fcetal life the ampullae develop in the lactiferous
ducts, which open on the apex of the nipple.

At puberty, the size of the gland increases, owing to an
increase in the parenchyma ; during pregnancy, the glandular
tissue proliferates, and the mamma reaches its full development ;
at the menopause, involution occurs in the more recently
developed portions.

The Mammary Gland possesses no capsule ; it consists of
a central portion and of peripheral branching processes which
radiate into the surrounding paramammary fat (Stiles). The
superficial fascia, which covers it, sends down fibrous processes,
called the ligaments of 'Cooper, to join the connective tissue septa
which ramify throughout the gland. Prolongations of the
parenchyma of the gland are found in the ligaments of Cooper,
in the loose retro-mammary tissue, and sometimes even in the
intervals between the fasciculi of the pectoralis major. When
the ligaments of Cooper are invaded by malignant disease,
they become shorter and cause dimpling of the skin, which, on
this account, is no longer freely movable over the breast.

The breast rests upon the pectoral fascia and extends from
the second rib above to the sixth costal cartilage below. At
the level of the fourth rib it extends horizontally from the
lateral border of the sternum to the fifth rib in the mid-axillary
line (Stiles). Its medial half rests, above, upon the pectoralis
major, and, below, on the aponeurosis of the external oblique
where it covers the upper part of the rectus abdominis. Its
lateral half lies upon the pectoralis major above, and on the
serratus anterior (s. magnus) and the external oblique (digitations
of origin) below. Spence's axillary tail is a narrow portion of
the gland, which reaches up under cover of the pectoralis major
as far as the third rib.

The arterial supply of the mammary gland is derived from
the lateral (long) thoracic (p. 31) and the anterior perforating

26 THE SUPERIOR EXTREMITY

branches — especially the second and third — which arise from
the internal mammary in the intercostal spaces and pass
forwards through the pectoralis major near the margin of the
sternum. I

The Lymph Vessels of the breast may be divided into two
sets — (i) the cutaneous,, (2) the glandular.

i. The cutaneous lymph vessels form a plexus beneath the
areola, and from it the vessels extend; in the fibrous septa of the
subcutaneous fat, towards the periphery of the breast, where
they join the extensive lymphatic plexus in the fascia enveloping
the pectoralis major — the pectoral plexus. (2) The glandular
lymph vessels, which surround the alveoli, lie in the intra-lobular
connective tissue and communicate in front with the cutaneous
plexus and behind with the pectoral plexus.

It is necessary to detail the various connections of the
pectoral plexus in order that the spread of malignant disease,
both by centrifugal permeation and by embolic processes, may
be understood. They can be conveniently tabulated.

Connections of Pectoral Plexus.

1. With subscapular lymph glands (p. 35), which drain the lateral part

of the plexus.

2. With pectoral lymph glands (p. 35), which drain the upper and lateral

part of the plexus.

3. With infra- clavicular lymph glands (p. 30), which drain the upper part

of the plexus.

4. With the lymph glands which lie along the internal mammary vessels

in the upper intercostal spaces, and through them, with the anterior
mediastinal lymph glands, which thus drain the medial part of the
plexus.

5. With the pectoral and cutaneous plexus of the opposite side, across the

front of the sternum.

6. With the sub-peritoneal plexus on the under surface of the diaphragm,

by communications which cross the costal margin, draining the
lower part of the plexus.

Mammary Abscess. — Superficial abscess formation (pre-
mammary abscess) is caused by organismal infection of the
cutaneous lymph vessels or of the glands which form
Montgomery's tubercles.

If the glandular lymph vessels become involved by a spreading
infection, the abscess forms in the substance of the breast
(intra-mammary abscess). In this case the abscess ramifies
throughout the mamma, giving rise to loculi, which may be
traversed by fibrous septa.

THE BREAST AND AXILLA

27

When the infection passes to the pectoral plexus, it gives
rise to an abscess behind the breast (retro-mammary abscess).
This variety more commonly arises from a deeper cause, such

Connections with pectoral plexus of opposite side

Internal mammary glands
Deep cervical glands, postero-inferior group [

Pectoralis major, clavicular part I
Pectoralis major, costo-sternal part
Apical glands i
Superficial infra-clavicular glands ;

Central axillary glands

Latissimus dorsi

Serratus anterior -
External oblique

Connections with sub-peritoneal lymph plexus

FIG. 8. — The Connections of the Pectoral Lymphatic Plexus. The lymph
vessels and glands which lie deep to the muscles are indicated by the
clotted lines and circles.

as empysema, tuberculous disease of a rib, etc., and it tends to
push the breast and the pectoralis major forwards ; after
perforating the latter, the abscess may point in the areola or
gravitate towards the infra-mammary groove.

Incisions for the pre- and intra-mammary abscesses radiate

28 THE SUPERIOR EXTREMITY

from the nipple, in order to avoid injuring the lactiferous ducts.
If the retro-mammary abscess is caused by a forward spread
from deeper structures, the breast may be turned upwards
by a long curved incision in the infra-mammary groove. In
this way good access is obtained and no important structures
are injured. The same approach serves for removal of the
breast in chronic mastitis and other simple conditions.

THE AXILLA. — The axilla is the space between the upper
part of the chest wall and the proximal part of the upper limb.
In shape it resembles a pyramid with a blunted apex, through
which the great vessels and nerves pass from the root of the
neck to the axilla. The apex is bounded, in front, by the
middle third of the clavicle, behind, by the upper border of the
scapula, and medially, by the outer border of the first rib.

Axillary Fascia. — The hollo wed-out base of the pyramid,
i.e. the floor of the axilla, is formed by the axillary fascia, which
is an extremely strong sheet. It is continuous in front with
the fascial envelope of the pectoralis major, and behind with
that of the latissimus dorsi. Below, and medially, it blends
with the fascia covering the serratus anterior (magnus), and
it is continuous laterally with the deep fascia of the arm. Owing
to the great strength of the axillary fascia, abscesses rarely
rupture through it spontaneously.

The Anterior Wall of the Axilla consists of two
strata. The Pectoralis major and its fascia form the superficial,
and the Pectoralis minor and the clavi-pectoral fascia form
the deep layer.

The Pectoral Fascia closely envelops the pectoralis major.
Above, it is attached to the clavicle, and, in its lateral part,
it forms the roof of the superficial infra-clavicular triangle.
Medially, it is attached to the sternum, and below it is continuous
with the fascial covering of the external oblique and the serratus
anterior. Laterally, it blends with the axillary fascia below
and with the fascia of the arm above.

The pectoral fascia contains the efferent mammary lymph
vessels, and hence the necessity for its exposure and removal in
cancer of the breast. The best access to the fascia is obtained
by an incision extending from the insertion of the pectoralis
major to the tip of the eighth costal cartilage of the opposite
side (Stiles). This incision divides so as to enclose the tumour
and an equally wide area of skin and cutaneous lymph vessels
all round it.

THE BREAST AND AXILLA

29

To expose the fascia completely, the skin above the incision
is dissected upwards and medially until the clavicle and the
opposite margin of the sternum are visible ; the skin below the
incision is undercut backwards until the level of the posterior
wall of the axilla is reached, and downwards until the sheath
of the rectus abdominis and the upper digitations of the external
oblique are well exposed.

The Pectoralis Major arises by a Clavicular Head from the
front of the medial third or more of the clavicle and by a Costo-
sternal Head from the front of the sternum, from the aponeurosis
of the external oblique, and from the upper five or six costal
cartilages. These two heads of origin remain quite distinct
from one another almost to the insertion into the lateral lip of
the inter-tubercular sulcus (bicipital groove). The pectoralis
major is a powerful adductor, and it helps in flexion and medial
rotation of the humerus. It is supplied by the lateral and
medial anterior thoracic nerves (C. 5, 6, and 7, C. 8 and T. i).

If the clavicular head is preserved in the operation of complete
excision of the breast, no movements are lost, although the
arm is weakened by the removal of the costo-sternal portion.

The deep stratum of the anterior wall of the axilla is formed
by the clavi-pectoral fascia, the pectoralis minor, and the
subclavius.

The Pectoralis Minor arises from the bony sternal extremities
of the third, fourth, and fifth ribs, under cover of the pectoralis
major, and runs upwards and laterally to be inserted into the
medial border of the coracoid process. It is supplied by the
medial anterior thoracic nerve (C. 8 and T. i), from the medial
cord of the brachial plexus. The nerve pierces the muscle
about i£ inches from its insertion and enters the pectoralis
major. The pectoralis minor helps in forward and downward
movements of the shoulder girdle ; and, when the scapula is
fixed, it acts as an elevator of the ribs.

The Subclavius, which lies between the clavicle and the
first rib, is supplied by a small nerve which is formed by twigs
from C. 5 and C. 6. It helps to steady the clavicle in movements
of the shoulder, by pulling it medially towards the sternum.

The Clavi-Pectoral Fascia extends from the clavicle above
to the axillary fascia below. It forms the fascial sheath of the
subclavius, and is attached to the edges of the groove for that
muscle on the clavicle. The layers enclosing the subclavius
fuse at its lower border to form the costo-coracoid membrane,

3°

THE SUPERIOR EXTREMITY

INNER

CORD

which fills in the gap in the deep stratum of the anterior axillary
wall between the subclavius above and the pectoralis minor
below (Fig. 9).

The Costo-Coracoid Membrane is attached medially to
the first costal cartilage, laterally to the coracoid process, while,
below, it splits to enclose the pectoralis minor. At its medial

end, it lies behind the clavi-
cular head of the pectoralis
major ; at its lateral end, it
constitutes the floor of the
superficial infra-clavicular
triangle. The infra-clavicular
lymph glands lie on its an-
terior surface.and it is pierced
by the cephalic vein (p. 50),
the thoraco-acromial (thor-
acic axis) artery and vein,
and the lateral anterior thor-
acic nerve. The axillary
sheath lies behind the mem-
brane, separated from it by
the loose fat and the apical
lymph glands of the axilla.
It is here that the surgeon
ligatures the first part of the

FIG. 9.— Diagram of a Section through axiHarv arterv taking the
the Anterior Wall nfthP Avilla aXUJOTy drtery, taKing

thoraco-acromial artery as
his guide.

At the lower border of the
costo-coracoid membrane the
clavi-pectoral fascia splits to
enclose the pectoralis minor,
and the layer on the anterior surface of the muscle is intimately
connected to the fascia on the deep surface of the pectoralis
major. Below the pectoralis minor the two layers of the clavi-
pectoral fascia fuse to form a single sheet, which passes down
to join the axillary fascia and is termed the suspensory ligament
of the axilla. This layer of fascia is attached laterally to the
deep fascia of the arm, in front of the great vessels and nerves.
The Thoraco-Acromial (Thoracic Axis) Artery arises from
the second part of the axillary artery, pierces the medial
part of the costo-coracoid membrane, close to the upper border

the Anterior Wall of the Axilla.

T A -r T .

L.A. f. Lateral anterior thoracic nerve.

I.A.T. Medial anterior thoracic nerve.

ART. Axillary artery, second part.

P. MA. Pectoralis major muscle.

P. Mi. Pectoralis minor muscle, connected

by costo-coracoid membrane with
SCL. Subclavius muscle.
CL. Clavicle.

THE BREAST AND AXILLA 31

of the pectoralis minor and breaks up into deltoid (p. 35),
acromial (p. 10), clavicular (p. 9), and pectoral branches. The
pectoral branches pass downwards in the interval between
the two pectoral muscles, accompanied by branches of the
lateral anterior thoracic nerve. In excision of the breast,
haemorrhage may be reduced by securing these branches prior
to removal of the sternal portion of the pectoralis major. They
may be hooked up on the forefinger through the interval between
the clavicular and sternal portions of the pectoralis major
(p. 3), as they wind round the upper border of the pectoralis
minor (Stiles).

The Lateral (Long) Thoracic Artery passes from the
second part of the axillary artery downwards and medially,
along the lower border of the pectoralis minor, to the fifth
intercostal space. Its External Mammary branch reaches the
mamma by passing medially over the pectoralis major.

The pectoral and infra-clavicular lymph glands, with their
efferent lymph vessels from the upper and lateral parts of
the pectoral plexus, are so intimately connected with the
pectoral fascia of the anterior axillary wall that this wall is
usually removed in malignant disease of the breast. The costo-
sternal portion of the pectoralis major is divided near its insertion
and is then reflected from its origin. As the cut muscle is
drawn forwards and laterally, the fascia covering the serratus
anterior and the external oblique is rendered tense, and may
be removed as a wide sheet as far back as the subscapularis.
It is at this stage of the operation that the long thoracic nerve
(of Bell) is in danger, as it runs down the medial wall of the
axilla between the serratus anterior and its covering fascia.

The Medial Wall of the Axilla is formed by the upper
five ribs and external intercostal muscles, partially covered by
the upper digitations of the serratus anterior.

The Serratus Anterior (S. magnus) arises from the lateral
surfaces of the upper eight ribs, a short distance in front of the
mid-axillary line. Its fibres pass backwards, closely applied
to the chest wall, and are inserted into the ventral aspect of the
vertebral border of the scapula. It receives its nerve-supply
from the long thoracic nerve (of Bell) (C. 5, 6, 7) (pp. 97, 131).
The serratus anterior pulls the scapula forwards, and, when
opposed by the rhomboids, it steadies the scapula in the
movements of forward pushing. In addition, by rotating the
scapula it helps to produce flexion of the upper arm beyond a

32 THE SUPERIOR EXTREMITY

right angle (p. 14), and, when the scapula is fixed by the
trapezius and the rhomboids, it acts as an elevator of the ribs.

The lateral cutaneous branches of the second and third intercostal
nerves pierce the medial wall and run laterally across the axilla.
They supply the skin over the floor of the axilla and the medial
aspect of the arm ; the uppermost is termed the intercosto-
brachial (intercosto-humeral) nerve, and it communicates with
the medial cutaneous nerve of the arm (lesser internal cutaneous).
In malignant disease of the breast intermittent pain may be
referred to the medial side of the arm, in the area supplied by
these two nerves. It is suggested that this is due to pressure
on the intercosto-brachial nerve by enlarged axillary lymph
glands ; but the pain is very frequently referred from the
irritated sympathetic branches supplying the mammary gland
itself.

The Lateral Wall of the Axilla, to which the
important vessels and nerves are closely related, is narrow and
is formed by the biceps, the coraco-brachialis, and the proximal
part of the humeral shaft.

The Axillary Sheath is a prolongation of the prevertebral
fascia (p. 112) from the neck. It encloses the vessels and
nerves (and some of the apical lymph glands), and gradually
becomes lost upon them as they pass through the axilla. In
malignant disease of the breast, the apical lymph glands are
removed, and they may be exposed by resecting a part of the
sheath and separating the artery from the vein.

AXILLARY ARTERY. — The course of the axillary artery may
be mapped out on the surface by drawing a line from the middle
of the clavicle to the medial side of the elevation formed by the
coraco-brachialis (p. 38), the limb being abducted to a right
angle. The vessel is about six inches long and extends from
the outer border of the first rib to the lower border of the
teres major. It is conveniently divided into three parts by
the pectoralis minor. The First Part lies above the muscle ;
the Second, behind the muscle ; the Third, below the muscle.

The First Part of the axillary artery lies behind the
costo-coracoid membrane and the clavicular head of the pectoralis
major, and it is crossed by the cephalic and thoraco-acromial
veins. Posteriorly, the artery rests on the first intercostal space
and the first digitation of the serratus anterior, but it is separated
from them by the long thoracic nerve (of Bell), and, usually,
the medial cord of the brachial plexus. To the lateral side are

THE BREAST AND AXILLA 33

the lateral and posterior cords of the brachial plexus ; to the
medial side, and overlapping the artery anteriorly, is the axillary
vein.

Ligature of this part of the artery has been referred to
already (p. 30). The collateral circulation is carried on by the
scapular anastomosis, where the transverse scapular (supra-
scapular) (p. 14) and the descending branch of the transverse
cervical, from the subclavian (p. 12), meet the subscapular and
circumflex scapular (dorsalis scapulae) branches from the
axillary. Further, branches from the intercostals anastomose
on the chest wall with the lateral (long) thoracic and subscapular
arteries and with the pectoral branches of the thoraco-acromial.

The superior thoracic is the only branch of the first part of
the axillary artery. It crosses the apex of the axilla to supply
the lymph glands and other structures in the first intercostal
space.

The Second Part of the axillary artery has the lateral
cord of the brachial plexus to its lateral side, the posterior
cord behind it, and the medial cord and the medial anterior
thoracic nerve, which separate the artery from the axillary vein,
to its medial side. Behind the artery and the posterior cord
there is a pad of fat, which intervenes between them and the
subscapularis muscle.

The branches of this part of the artery are the thoraco-
acromial (p. 30) and the lateral thoracic (p. 31).

The Third Part of the axillary artery lies under cover
of the pectoralis major above, but it is subcutaneous below.
There are two nerves on each side of the artery. Laterally, lie
the lateral head of the median and the musculo-cutaneous nerve,
which deviates laterally to pierce the coraco-brachialis (Fig. 10).
Anteriorly, lie the medial head of the median and the medial
cutaneous nerve of the forearm (internal cutaneous nerve).
Medially, the ulnar nerve separates the artery from the axillary
vein, and the medial cutaneous nerve of the arm (lesser internal
cutaneous nerve) is closely applied to the medial side of the
vein. Posteriorly are the radial (musculo-spiral) and axillary
(circumflex) nerves, but the latter leaves the artery at the
lower border of the subscapularis by passing backwards into
the quadrilateral space.

The Third Part of the axillary artery is superficial, and is
the site of election for Ligation. The vessel may be tied
immediately above the origin of the subscapular or between

3

34 THE SUPERIOR EXTREMITY

this vessel and the posterior circumflex. In the former case,
the circulation is carried on by the anastomosis between the
intercostals, lateral thoracic, descending branch of transverse
cervical, transverse scapular (supra-scapular), and thoraco-
acromial arteries, on the proximal side of the ligature, and the
subscapular and humeral circumflex arteries, on the distal side
of the ligature.

Collateral Circulation. — The circumflex arteries anastomose with
the acromial branch of the thoraco-acromial and the transverse scapular
(p. 1 8). The subscapular anastomoses with the descending branch of the
transverse cervical and the transverse scapular arteries in the scapular
anastomosis, and with the intercostals, the lateral thoracic and pectoral
branches of the thoraco-acromial in the serratus anterior, near the inferior
angle of the scapula.

When the axillary artery is tied between the subscapular and circumflex
vessels, the anastomosis just referred to between the circumflex, the acromial
branch of the thoraco-acromial and the transverse scapular arteries re-
establishes the circulation.

When the subscapular and circumflex vessels arise by a common trunk
and a ligature is applied distal to this vessel, the collateral anastomosis follows
the same course as in ligature of the brachial artery proximal to the origin
of the (superior) profunda (p. 43).

Branches of the Third Part of the Axillary Artery.— (i) The
subscapular is the largest branch of the axillary artery. It arises near the
lower border of the subscapularis, along which it descends accompanied
by its companion vein and the thoraco-dorsal (long subscapular) nerve.
A short distance from its origin it gives off the circumflex scapular (dorsalis
scapulce) artery, which winds round the axillary border of the scapula close,
to the bone to reach its dorsal surface (p. 33). (2) The posterior circumflex
(p. 18). (3) The anterior circumflex (p. 18).

These three arteries occasionally arise by a common trunk, which leaves
the third part of the axillary artery near its commencement.

Aneurism of the first part of the axillary artery pushes forwards the costo-
coracoid membrane and tends to project below the clavicle in the superficial
infra-clavicular triangle. Aneurism of the third part projects into the axilla
and gives rise to a swelling or convexity of the floor of the axilla. Both
varieties may press upon the axillary vein and obstruct the venous return,
thus causing swelling and redema of the upper limb.

The Axillary Vein is formed at the lower border of the
teres major by the basilic vein, and is soon joined by the venae
comites of the brachial artery. It ends at the outer border
of the first rib, where it becomes continuous with the subclavian
vein. As it passes through the axilla it lies to the medial side
of the artery, but is separated from it by the ulnar nerve, below,
and by the medial cord of the plexus, above. When the arm is
abducted, the vein lies in front of the artery and hides it from
view. Its principal tributaries are the cephalic and the
subscapular veins. The latter possesses a wide anastomosis
with the veins of the thoracic wall near the inferior angle of

THE BREAST AND AXILLA 35

the scapula. The subscapular vein and the branches of the
anastomosis are associated with the posterior group of lymph
glands, and all these structures are removed, as a routine measure,
in excision of the breast. After the thoraco-dorsal (long
subscapular) nerve has been isolated, the subscapular vessels
are tied close to the axillary artery and then stripped downwards.
In the process the lower (middle) subscapular nerve is exposed,
as it runs laterally, in front of the subscapularis and behind the
vessels, to reach the teres major.

The LYMPH GLANDS of the axilla are arranged in four groups :

1. The Pectoral lymph glands lie in the medial part of
the interval between the suspensory ligament of the axilla
(p. 30) and the posterior surface of the pectoralis major. They
drain not only the breast, but also the superficial layers of the
anterior abdominal wall above the umbilicus.

An abscess arising from these glands cannot extend upwards
into the neck as the two layers of fascia between which it lies
are both attached to the clavicle (Fig. 9). This abscess tends
to point either at the upper or lower border of the pectoralis
major. Incisions should be made parallel to these borders to
avoid injuring the deltoid branch of the thoraco-acromial artery
(p. 30) in the one case; and the lateral thoracic artery (p. 31)
in the other.

2. The Central lymph glands (Leaf) accompany the
axillary vein and lie on the lateral wall of the axilla. They
receive the efferents from the upper limb and are involved early
in lymphangitis of the fingers and forearm.

An abscess arising from these glands lies in the axilla behind
the clavi-pectoral fascia and produces a bulging of the axillary
fascia. The pus cannot pass far backwards owing to the
attachment of the serratus anterior to the scapula, but it may
burrow through the intercostal spaces and infect the pleura, or
it may pass upwards behind the axillary sheath (p. 32) and
appear in the root of the neck. Rarely, the pus burrows through
the subscapularis and infects the shoulder-joint.

This abscess should be opened through the axillary fascia
by cutting in the direction of the medial wall and parallel to the
long thoracic nerve (of Bell). In this way the lateral thoracic
artery on the anterior wall, the subscapular vessels and thoraco-
dorsal nerve on the posterior wall, and the great vessels and
nerves on the lateral wall, are all avoided.

3. The Subscapular group of lymph glands lies on the

3 a

THE SUPERIOR EXTREMITY

subscapularis at the inferior angle of the scapula and is closely
associated with the subscapular vessels and the thoraco-dorsal
nerve. They receive efferents from the pectoral plexus and
afferents from the superficial layers of the back corresponding
to the thoracic part of the vertebral column.

Pectoralis major, clavicular part

Cephalic vein
Clavicle

Pectoral branches of thoraco-

acromial artery

Pectoralis minor, partially

reflected

Infra -clavicular lymph glands

Apical lymph glands _MS^.

Central lymph
glands

Thoraco-dorsal
|3C. r • nerve
f i 7" Subscapular vein

~3'i^S^~Tf-4 .Long thoracic nerve

~~^T - Subscapular lymph glani
-gpJ Latissimus dorsi
Serratus anterior

Pectoralis
major, pars
abdominalis

External oblique

FIG. 10. — The Axilla and its Lymph Glands. A small part of the anterior
wall of the rectus sheath has been removed, and the pectoralis minor
has been partially divided.

Abscesses arising in connection with this group may spread
in the same directions as in (2). They should be opened by an
incision parallel to the axillary border of the scapula, so as
to avoid injury to the subscapular vessels and nerve.

4. The Apical lymph glands are situated at the apex of
the axilla and lie behind the costo-coracoid membrane. Some

THE BREAST AND AXILLA 37

lie on the first intercostal space ; others along the axillary
sheath ; while others are situated within the sheath in contact
with the vein. They receive the efferents of the subscapular,
pectoral, and central groups, and are connected, through the
costo-coracoid membrane, with the infra -clavicular lymph
glands in the superficial infra-clavicular triangle. The apical
lymph glands may become adherent to the axillary vein in
malignant disease and necessitate the excision of a part of that
vessel ; they may also press upon the cephalic vein, as it pierces
the costo-coracoid membrane in such a way as to render it
prominent throughout its course, in the arm. Efferents from
this group open into the lymph glands at the root of the neck,
and Halstead considers that these should be removed in the
routine operation for scirrhus mammae.

The Posterior Wall of the Axilla is formed by the subscapularis,
teres major, and the tendon of the latissimus dorsi.

The Subscapularis arises from the venter of the scapula and passes upwards
and laterally in front of the shoulder -joint to be inserted into the lesser
tubercle of the humerus and the capsule of the joint. It helps in adduction
and medial rotation of the arm and receives its nerve-supply from the upper
(short) and lower (middle) subscapular nerves (C. 5 and 6).

The Latissimus dorsi (p. 269) is inserted into the floor of the intertubercular
sulcus of the humerus. It helps in extension, adduction, and medial rotation
of the arm and is supplied by the thoraco-dorsal (long subscapular) nerve
(C. 6, 7, and 8).

The Teres major arises from the dorsal aspect of the inferior angle of the
scapula and runs upwards and laterally to be inserted into the medial lip
of the intertubercular sulcus. Its course corresponds to that of the latissimus
dorsi and its actions are therefore similar. It is supplied by the lower (middle)
subscapular nerve (C. 5 and 6).

The great vessels and nerves of the axilla lie on the upper part of this
wall, and the subscapular vessels (p. 34) and the three subscapular nerves,
which all arise from the posterior cord, are closely related to it.

The BRACHIAL PLEXUS and its important branches will be
considered in detail in a subsequent chapter (p. 95), but the
nerves must be identified as they surround the third part of the
axillary artery. The Median is recognised by its two heads
of origin and by its great size. The Musculo - Cutaneous is
recognised by its lateral position and by its deviation to reach
and pierce the coraco-brachialis. It is smaller than the median,
but occasionally it includes a large part of the lateral head of
the median, and the two nerves then tend to resemble one
another and can be distinguished only by their relative positions.
This part of the lateral head subsequently joins the median
nerve in the arm.

Some difficulty may be experienced in distinguishing the

36

38 THE SUPERIOR EXTREMITY

Ulnar from the Medial Cutaneous Nerve of the Forearm
(Internal Cutaneous). They both arise from the medial cord
and are hidden at their origin by the axillary vein. The medial
cutaneous is the more anterior and the smaller of the two.

The Radial (Musculo-spiral) is the direct continuation of
the posterior cord and consequently lies behind the artery.
It can be distinguished from the ulnar by its greater size and
by its position.

REGION OF'(UPPER) ARM.

Muscular Landmarks. — The elevation produced by the
biceps on the front of the arm is limited by the lateral and
medial bicipital furrows. In its proximal part the medial furrow
is obscured by the coraco-brachialis } which is seen best when
resistance is offered to adduction of the abducted arm.

When the elbow is forcibly extended against resistance, the
lateral head of the triceps gives rise to a distinct prominence,
which lies below and parallel to the posterior border of the
deltoid. The long head of the triceps can be seen, as it emerges
from under cover of the proximal part of the posterior border
of the deltoid, when the abducted arm is viewed from behind.
The muscular mass on the medial aspect of the back of the
arm is produced by the large medial head of the triceps.

The Deep Fascia of the Arm receives attachments to the
humeral epicondyles and the subcutaneous border of the
olecranon in the elbow region. The Medial and Lateral
Intermuscular Septa are processes of fascia which extend from
the ensheathing layer to the epicondylic ridges and shaft of the
humerus. The medial septum extends from the medial
epicondyle to the insertion of the coraco-brachialis, the lateral
from the lateral epicondyle to the insertion of the deltoid. These
septa, together with the humerus, divide the arm into an anterior
and a posterior compartment, and, to a certain extent, limit
the course of pus or hsemorrhagic extravasation.

The Triceps Brachii occupies the whole of the posterior
compartment of the arm, and is inserted into the proximal
surface of the olecranon. It is a powerful extensor of the elbow,
and it is supplied by the radial (musculo - spiral) nerve (C. 7
and 8).

REGION OF (UPPER) ARM 39

The Axillary (Circumflex) Nerve (p. 33) winds horizontally
round the surgical neck of the humerus in the quadrilateral
space, where it is in close relation to the dependent part of the
capsule of the shoulder- joint (p. 16). In this region it may be
injured by the pressure of a crutch, by the head of the humerus
in sub-glenoid dislocations, and by the fragments in fracture of
the surgical neck. The nerve supplies the teres minor and the
deltoid. It can be mapped out on the surface by a horizontal
line, which intersects the line drawn from the lateral border of
the acromion to the insertion of the deltoid, at the junction of
its proximal and middle thirds. The results of injury to the
axillary nerve are described on page 101.

Surgical Approach to the Proximal Part of the
Humerus. — In disease or injury of the Proximal Part of the
Shaft (or diaphysis) of the humerus, the best approach is
obtained by a long incision, parallel to the posterior border of
the deltoid (Stiles). When the muscle is undermined and
retracted, the quadrilateral space is exposed, and the large
cutaneous branch of the axillary nerve is seen passing forwards
round the edge of the deltoid. The quadrilateral space is bounded
above by the teres minor, below by the teres major, laterally
by the surgical neck of the humerus, and medially by the long
head of the triceps. Through it the axillary nerve and the
posterior circumflex vessels pass backwards in close relation to
the surgical neck of the humerus and the dependent part of the
capsule of the shoulder -joint. Anterior to the origin of the
lateral head of the triceps and above the insertion of the deltoid,
the humerus is uncovered by muscles and offers good access to
the surgeon.

The proximal part of the diaphysis of the humerus may
be resected subperiosteally for tuberculous osteomyelitis. After
the periosteum has been elevated, the diaphysis need only be
divided distal to the disease, as the part to be resected may
then be wrenched out from its periosteal sheath. In this way
the epiphyseal cartilage is left attached to the epiphysis and
the joint cavity is not opened (Fig. 6).

Below the teres major the Radial (musculo - spiral) nerve
lies on the long head of the triceps, and after supplying this
muscle, it enters the radial groove in company with the (superior)
profunda branch of the brachial artery. In the groove it supplies
the medial and lateral heads of the triceps between which it
lies, and it passes distally and laterally across the back of the

3c

40 THE SUPERIOR EXTREMITY

arm. At the distal end of the groove it pierces the lateral
intermuscular septum and enters the anterior compartment
of the arm. The point at which it pierces the septum may be
indicated on the surface at the union of the proximal and middle

Spine of scapula N. suprascapularis

j A M. dehoid.us

M. infraspinatus
A. circumflex, scap.

(O.T. dorsalis I. -^

scap.)
M. teres minor J

M. subscapularisJ

M. teres major

Triang. space .
Quadrangular space

M. triceps cap. long
N. radialis (O.T. musculo-spiral)

Bursa subacromialis

M. infraspinatus
_ Capsula artic. Articulat.
humeri ;
N. to m. teres minor

M. deltoideus

N. axillaris (O.T.
circumflex) ram. sup.
N. axillaris,
ram. inf.

N. cutan. brach.
~ lat.

- M. triceps, cap. lat.

A. brachialis
M. triceps, cap. lat.

N. to m. triceps, cap. nied.

M. triceps, cap. med.

N. ulnaris

Epicond. med

N. flex. carp. uln.

Olecranon— --.

N. radialis (O.T.
musculo-spiral)

A. prof, brachii ram. ant.

A. prof brachii ram. post.
N. cut. antib. dorsalis
M. brachialis

Epicond. lat.

A. inteross. recurr.

M. anconaeus
Mm. ext. dig.
comm. et dig. quint.
M. ext. carp, ulnaris

FIG. ii. — The Back of the Arm.

thirds of the line joining the lateral epicondyle to the insertion
of the deltoid. A line drawn across the back of the arm from
the termination of the axillary artery to this point maps out
the nerve as it lies in the radial groove.

In the anterior compartment the radial (musculo-spiral)

REGION OF (UPPER) ARM 41

nerve lies on the lateral border of the brachialis (b. anticus),
and is covered in front by the brachio-radialis (supinator longus)
proximally and the extensor carpi radialis longus distally. It
ends in front of the lateral epicondyle of the humerus by dividing
into superficial (radial) and deep (posterior interosseous) branches.
Callus following a fracture of the shaft of the humerus
sometimes implicates the radial (musculo - spiral) nerve,
necessitating operative interference. The nerve can be
conveniently found as it pierces the lateral intermuscular
septum, and it can then be traced upwards by cutting through
the musculo - tendinous roof of the radial groove, until the
damaged portion is found. In the usual procedure the nerve
is sought for in the anterior compartment by separating the
brachio-radialis from the brachialis (b. anticus). Owing to the
absence of a well-marked septum, the groove between these
muscles, which are closely applied to one another, is not easy
to determine. The interval between the brachialis and the
biceps may inadvertently be opened, in which case the musculo-
cutaneous nerve is exposed (vide infra). Injury to the radial
(musculo-spiral) nerve is dealt with on p. 101.

Muscles of the anterior compartment. — The coraco - brachialis
is inserted into the middle of the shaft of the humerus on the medial side,
and helps in flexion and adduction of the arm. Its nerve -supply from
the musculo-cutaneous nerve is derived entirely from C. 7.

The biceps brachii arises by a long head (p. 18) and by a short head from
the tip of the coracoid process. It is inserted into the posterior part of the
tuberosity of the radius and is separated from the anterior part by a bursa.
Primarily, it is a flexor and supinator of the forearm ; secondarily, it helps
to produce flexion and adduction at the shoulder. The musculo-cutaneous
nerve (C. 5 and 6) supplies both heads.

The biceps occupies the greater part of the anterior compartment of the
arm, and its medial border is the surgical guide to the brachial artery. The
belly or either head of the muscle may be ruptured during violent movements,
and, as a result, flexion of the elbow and forcible supination are much
weakened.

The brachialis (b. anticus) covers the distal half of the anterior surface
of the humerus and passes in front of the anterior ligament of the elbow to
be inserted into the front of the coronoid process of the ulna. It is a powerful
flexor of the elbow, and it derives its nerve-supply from the musculo-cutaneous
(C. 5 and 6) and the radial (musculo-spiral) nerves (C. 5 and 6).

In fracture of the distal part of the shaft of the humerus a portion of
the brachialis may become interposed between the two fragments causing
non-union.

The shaft of the humerus should be examined along the
lines of the intermuscular septa (p. 38), as the anterior and
posterior surfaces of the bone are obscured by muscles. At
its distal end, however, it may be examined by deep pressure

42 THE SUPERIOR EXTREMITY

through the brachialis in front and the triceps behind, provided
that the muscles are relaxed by supporting the elbow.

Fractures of the Humerus.— Some reference must be
made to the common sites of fracture of the humeral shaft on
account of the displacement of the fragments. Although the
displacements may be due primarily to the direction of the
force causing the fracture, ultimately they are due to the action
of the muscles attached to the fragments.

Fractures may occur :

1. Through the Anatomical Neck (p. 23).

2. Through the Surgical Neck. — The proximal fragment
is slightly abducted by the supra-spinatus, but is not rotated,
as the lateral rotators attached to the greater tubercle are
opposed by the subscapularis on the lesser tubercle. The
distal fragment is drawn proximally by the triceps, the biceps,
and the deltoid, and medially by the muscles inserted into the
intertubercular sulcus (bicipital groove).

3. Immediately Proximal to the Insertion of the Deltoid.
—The proximal fragment is adducted by the latissimus
dorsi, the pectoralis major, and the teres major. The distal
fragment is drawn proximally by the deltoid, the triceps, and
the biceps.

4. Distal to the Insertion of the Deltoid. — The proximal
fragment tends to be abducted by the deltoid. The distal
fragment is drawn proximally and somewhat medially by the
biceps and the triceps, which act through the elbow-joint.

5. Proximal to the Epicondyles (p. 63). — The distal
fragment is usually drawn proximally behind the proximal
fragment by the biceps and the triceps. The distal end of the
proximal fragment may perforate the brachialis and injure the
brachial artery.

The Musculo-cutaneous nerve, on leaving the axillary
artery (p. 33), supplies the coraco-brachialis and then pierces it.
It runs distally between the biceps in front and the brachialis
behind, supplying both muscles, and emerges at the elbow at
the lateral side of the tendon of the biceps (p. 47). The results
of injury to this nerve are detailed on p. 102.

The Brachial Artery is the direct continuation of the
axillary. It begins at the lower border of the teres major and
ends in the cubital fossa (p. 45), half an inch distal to the
mid -point of the line joining the two epicondyles, where it
divides into the radial and ulnar arteries.

REGION OF (UPPER) ARM 43

In its proximal third the artery lies to the medial side of
the humerus and can be compressed laterally against the bone.
In ligature of this part the artery is found immediately under
the deep fascia, but it is overlapped laterally by the coraco-
brachialis, from which it is partially separated by the median
nerve. Both the medial cutaneous nerve of the forearm (internal
cutaneous) and the ulnar nerve (p. 38) lie to its medial side
and separate it from the basilic vein. Behind the artery lie
the long head of the triceps and the radial (musculo-spiral) nerve.

The middle third of the brachial artery can be compressed
backwards and laterally against the bone. In ligation of
this part the artery is found to be overlapped by the medial
border of the biceps, and to be covered by the median
nerve, which crosses it very obliquely about the middle of the
arm. The ulnar nerve lies to its medial side, but is diverging
from the artery to reach the medial intermuscular septum.
Posteriorly, it lies on the insertion of the coraco-brachialis and
on the brachialis. The medial cutaneous nerve of the forearm
(internal cutaneous) and the basilic vein are both separated
from the vessel by the deep fascia, which they pierce at the
middle of the arm.

The distal third of the artery lies in front of the distal
part of the humerus and can be compressed backwards against
it. In ligature of this part, the artery is found to be overlapped
by the medial border of the biceps, but near its termination it
lies to the medial side of the tendon of that muscle and is crossed
anteriorly by the lacertus fibrosus (bicipital fascia) (p. 45).
The median nerve lies to its medial side.

Branches. — (i) The (Superior) Pro/undo, arises near the commencement
of the brachial artery and runs with the radial (musculo-spiral) nerve.

(2) The Superior Ulnar Collateral (Inferior Profunda) usually arises near
the middle of the arm (p. 44).

(3) The Inferior Ulnar Collateral (Anastomolica Magnd) (p. 44).

(4) The Nutrient artery usually arises from a muscular branch to the
brachialis ; it may be injured in fractures of the humerus, and, in these cases,
it is said that delayed union results.

Collateral Anastomosis — (a) Ligature Proximal to the Origin of the
Profunda Artery. — The circulation is re-established through an anastomosis
which occurs between a descending branch from the posterior circumflex
(p. 1 8) and an ascending branch from the profunda.

(V) Ligature between the Origins of the Profunda and the Superior Ulnar
Collateral (Inferior Profunda). — The profunda artery divides into anterior
and posterior branches at the distal end of the radial (musculo-spiral) groove.
The anterior branch accompanies the radial (musculo-spiral) nerve into the
groove between the brachio-radialis and the brachialis to anastomose with
the radial recurrent, which enters the same groove at its distal end. The

44 THE SUPERIOR EXTREMITY

posterior branch runs distally behind the lateral intermuscular septum and
anastomoses behind the lateral epicondyle with the dorsal interosseous
recurrent (p. 71), which ascends under cover of the anconseus, upon the
supinator (s. brevis) and the annular (orbicular) ligament. It is also joined
by a transverse branch from the inferior ulnar collateral (anastomotic) artery.

(c) Ligature between the Origins of the Superior and Inferior Ulnar Collateral
Arteries (Inferior Profunda and Anastomotic). — The Superior Ulnar Collateral
accompanies the ulnar nerve (p. 43). The Inferior Ulnar Collateral arises
two inches proximal to the bend of the elbow and runs medially upon the
brachialis, passing behind the median nerve. It gives off an anterior branch,
which runs distally in the groove between the brachialis and the pronator
teres to anastomose with the anterior ulnar recurrent. The artery then
pierces the medial intermuscular septum and joins the superior ulnar collateral
to anastomose, behind the medial epicondyle, with the posterior ulnar re-
current.

The anastomosis detailed in (b) will also help to re-establish the circulation.

(d) Ligature just above the Termination of the Brachial Artery. — The
collateral circulation is the same as that described in (c).

The Medial Supracondylar Triangle is bounded laterally
by the brachial artery and medially by the medial intermuscular
septum. Its base is formed by the medial part of the inter-
condylar line. The triangle contains the median nerve and
the epitrochlear lymph gland, the former behind the deep fascia,,
and the latter superficial to it. This gland is very often the
seat of lymphadenitis and abscess formation,, secondary to
septic infection of the fingers or forearm. In excision of the
gland the volar branch of the medial cutaneous nerve of the
forearm (internal cutaneous nerve) may be injured (p. 48).

THE REGION OF THE ELBOW.

Bony Landmarks. — Both Epicondyles of the Humerns are
subcutaneous and are easily recognised ; the medial is the
more prominent, while the lateral can readily be traced upwards
into the lateral epicondylic ridge. The medial epicondyle is
the more posterior, since, when the arm is at rest by the side,
the humerus is medially rotated. The line joining the two
epicondyles is horizontal, and, in complete extension of the
elbow, it passes through the proximal border of the Olecranon,
which also is subcutaneous As the elbow is flexed, the olecranon
descends, till in full flexion it lies at least an inch distal to the
epicondyles. Between the dorsal surface of the olecranon and
the overlying skin there is a bursa, which is frequently infected,

THE REGION OF THE ELBOW 45

through abrasions of the skin, after falls on the elbow. This
may cause cellulitis in the forearm from direct spread. Chronic
inflammation of this bursa is not uncommon in miners.

The Head of the Radius can be felt on the posterior aspect
of the limb. When the forearm is flexed, it lies nearly an inch
in front of the lateral epicondyle, the interval between the two
being occupied by the capitulum (capitellum) of the humerus.
When the forearm is fully extended, the tip of the finger may
be inserted into a distinct hollow immediately proximal to the
head and behind the radial collateral (external) ligament. This
hollow corresponds to the lateral and posterior part of the
radio - humeral joint, and immediately proximal to it the
subcutaneous posterior aspect of the lateral epicondyle can be
made out. If the elbow is grasped by the hand so that the
olecranon fits into the palm, while the thumb rests over the
head of the radius, the latter will be felt to rotate when the
forearm is alternately pronated and supinated.

Muscular Landmarks. — The flexor muscles on the medial
side, and the extensor and supinator muscles on the lateral side,
bound the cubital fossa, a triangular depression in front of the
elbow, distal to the intercondylar line. Entering the fossa is
the strong tendon of the biceps, and the examining finger can
readily slip into the depression between this tendon and the
brachio-radialis. From the medial border of the tendon the
lacertus fibrosus (bicipital fascia) passes distally and medially
to blend with the fascia covering the flexor muscles. It hinders
the examination of the depression between the biceps tendon
and the flexor muscles, but if the finger is inserted behind its
prominent proximal border, the pulsations of the brachial artery
can readily be felt.

Superficial Nerves of the Arm, Elbow Eegion, and
Forearm. — The proximal part of the lateral aspect of the arm
is supplied by the Axillary (Circumflex) Nerve (C. 5 and 6). Be-
tween this area and the lateral epicondyle the skin is supplied
by the proximal division of the Dorsal Cutaneous Nerve of the
Forearm (Upper External Cutaneous Branch of Musculo-SpiraJ)
(C. 5 and 6), which arises just before the radial (musculo-spiral)
nerve penetrates the lateral intermuscular septum. It at once
pierces the deep fascia and associates itself with the cephalic
vein. The Distal Division of the Dorsal Cutaneous Nerve of the
Forearm (Lower External Cutaneous Branch of Musculo-SpiraT)
(C. 6 and 7), arises just distal to the last-named, runs distally

46

THE SUPERIOR EXTREMITY

behind the lateral epicondyle and supplies the skin on the back
of the forearm as far as the wrist (Fig. 13).

Posterior supraclavicular nerve*

Lateral cutaneous nerve of the arm

Posterior cutaneous nerve of the arm

Intercosto-brachiat nerve -

Branch of medial cutaneous nerve of

forearm

Medial cutaneous nerve of the arm

Dorsal cutaneous nerve of forearm, \
proximal and distal branches /

Medial cutaneous nerve of forearm

Cephalic vein

Basilic vein

Median basilic vein

Median cephalic vein

Lateral cutaneous nerve of forearm

Profunda vein
Cephalic vein

Basilic veins -j
Median vein

Palmar cutaneous branch of median nerve
Palmar cutaneous branch of ulnar nerve

Palmar cutaneous branch of superficial
branch of radial nerve

FIG. 12. — The Superficial Nerves and Veins on the Front of the Upper Limb.

The lateral aspect of the forearm is supplied by the Lateral
Cutaneous Nerve, which is the terminal part of the Musculo-

THE REGION OF THE ELBOW 47

Cutaneous Nerve (C. 5 and 6). After it pierces the deep fascia

Posterior supraclavicular nerves

Lateral cutaneous nerve of arm

( Posterior cutaneous nerve of

\ arm

/ Dorsal cutaneous nerve of

\forearm, proximal branch

Intercosto-brachial nerve

Medial cutaneous nerve of arm
Dorsal cutaneous nerve of fore-
arm, distal branch

Medial cutaneous nerve of forearm,

ulnar branch

Lateral cutaneous nerve of forearm,
dorsal branch

—Superficial division of radial
Dorsal branch of ulnar nerve

FIG. 13. — The Superficial Nerves on the Dorsal Aspect of the Upper Limb.

(p. 42), it crosses the median cephalic vein and divides into
volar (anterior) and dorsal branches.

The former supplies the front of the forearm as far as the

THE SUPERIOR EXTREMITY

thenar eminence ; the latter winds over the brachio-radialis to

supply the posterior surface
of the forearm as far as the
wrist. It lies lateral to the
dorsal cutaneous nerve of the
forearm (lower external cut-
aneous branch of musculo-
spiral).

The medial aspect of the
arm is supplied above by the
Inter co sto-brachial Nerve (T.2),
(p. 32), and, more posteriorly,,
by the Dorsal Cutaneous Nerve
of the Arm (C. 8) (Internal
Cutaneous Branch of Musculo-
spiral), which arises before the
radial nerve enters its groove
on the back of the humerus.

Distal to this area the skin
is supplied by the Medial
Cutaneous Nerve of the Arm
(Lesser Internal Cutaneous
Nerve) (T. i and 2), as far as
the medial epicondyle. The
skin covering the biceps is
supplied by the Medial Cut-
aneous Nerve of the Forearm
(Internal Cutaneous Nerve) (C.
8 and T. i), which pierces the
deep fascia at the insertion of
the coraco-brachialis and ac-
companies the basilic vein.
Just proximal to the medial
epicondyle it divides into volar
(anterior) and ulnar (posterior)
FIG. 14.— Schematic Representation of branches which Supply the
the Distribution of the Spinal Nerves medial half of the forearm as
to the Skin on the Anterior Aspect , ^, • ,

of the Upper Limb. far as the WTlst'

It will be observed that

V.A.L, Ventral axial line.

the skin on the lateral aspect

of the limb is supplied by the upper nerves of the brachial
plexus, and that on the medial side by the lower. The innerva-

THE REGION OF THE ELBOW

49

tion of the limb at an early stage of development provides a
useful explanation.
At the fourth week
of embryonic life
the upper limb pro-
jects from the side
of the neck region
as a small bud,
which possesses a
ventral and a dor-
sal surface, a ceph-
alic (pre-axial) and
a caudal (post-
axial) border. The
anterior rami (ant-
erior primary divi-
sions) of the lower
four cervical and
the first thoracic
nerves grow out
into the bud ; C. 5
supplies the pre-
axial border, and
T. i the post-axial.
As the limb length-
ens, C. 6 and C. 8
reach the respec-
tive borders of the
bud, but C. 7 be-
comes situated
deeply in its sub-
stance and reaches
the surface only at
the distal part of
the limb.

When wounds
or incisions on the
lateral aspect of
the forearm heal,
they may include twigs from the musculo-cutaneous nerve
in the cicatrix. The irritation of the nerve reflexly stimulates
the segments of the spinal medulla (C. 5 and 6) from which the

FIG. 15. — Schematic Representation of the Distribu-
tion of the Spinal Nerves to the Skin on the
Dorsal Aspect of the Upper Limb.
D.A.L. Dorsal axial line.

50 THE SUPERIOR EXTREMITY

nerve arises, with the result that muscles supplied by these
segments — the biceps and the brachialis (b. anticus) — may be
thrown into spasm. In this way the condition of " Bent Arm "
arises ; and it can be cured only by excision of the cicatrix.

Superficial Veins of Elbow and Forearm. — The superficial veins
of the forearm arise from the plexuses of the digits and hand, and, although
liable to variation, their arrangement at the elbow is fairly constant. The
Median Vein begins near the dorsal radial tubercle (p. 46), and winds round
the radial border of the forearm. It ends at the apex of the cubital fossa by
dividing into the Median Basilic and Median Cephalic veins, soon after it
has received its chief tributary, the profunda, from the deeper structures of
the forearm (Fig. 12).

The Median Basilic passes proximally and medially, superficial to the
lacertus fibrosus (bicipital fascia), and in front of the medial epicondyle it
joins the Basilic vein, which ascends from the ulnar side of the hand. There-
after the basilic vein ascends in the medial bicipital furrow as far as the
insertion of the coraco-brachialis, where it pierces the deep fascia (p. 34).
The Cephalic vein, which arises on the radial side of the hand, is joined by the
median cephalic in front of the lateral epicondyle. It passes proximally
on the deep fascia over the lateral aspect of the biceps brachii and enters the
groove between the deltoid and the pectoralis major, which conducts it to
the superficial infra-clavicular triangle.

It is important to recognise that most of the venous return from the hand
and forearm passes by the profunda to the median and then to the basilic
and cephalic veins, which are superficially placed, whereas only a small pro-
portion returns by the vense comites of the brachial artery.

On this account the venous return is easily controlled, and the arm is
therefore suitable for the purpose of Bier's congestive treatment in acute
infective conditions.

Bandages, too tightly applied, very easily produce such oedema and
pressure that Volkmann's ischaemic contracture or even gangrene of the
limb may follow.

Volkmann's Ischsemic Contracture produces a deformity in which
the fingers and wrist gradually assume a flexed attitude, owing to an inter-
stitial fibrosis of the flexor muscles of the forearm. When the wrist is
passively extended, the flexion of the fingers is increased, as the fibrosed
flexor muscles cannot stretch. The extensor muscles become stretched
and weakened by the constant flexion of the fingers, and they appear to be
paralysed. On flexion of the wrist, which loosens the flexors and over-
stretches the extensors, it will be found that the extensors of the fingers are
able to produce a weak movement, a feature which serves to differentiate
the condition from radial (musculo-spiral) paralysis (p. 102).

The median basilic and median cephalic are the veins
commonly used for transfusion of saline or for intravenous
injection of drugs. They may be rendered prominent by allowing
the arm to hang downwards for a few minutes or by applying
a bandage round the arm tight enough to constrict the veins
without affecting the artery.

The Lymph Vessels of the digits and hand are closely
associated with the superficial veins, and the main trunks
accompany the bigger veins in the forearm. Those of the ulnar

THE REGION OF THE ELBOW 51

side open into the epitrochlear lymph gland (p. 44), while the
median and radial lymph trunks open into lymph glands which
lie in the cubital fossa., or, in the absence of these, into the
epitrochlear lymph gland. The efferents from these glands
follow the course of the basilic vein and terminate in the
central group of the axillary lymph glands (p. 35). Some-
times the lymph vessels from the lateral three digits pass
directly along the radial side of the arm and end in the
infra -clavicular (p. 30) or even in the pectoral lymph
glands (p. 35).

The Elbow and Proximal Radio-Ulnar Joints.— At
the elbow-joint the Trochlea and Capitulum of the humerus
articulate with the Semilunar Notch (Greater Sigmoid Cavity)
of the ulna and the proximal surface of the head of the radius,
respectively. At the proximal radio-ulnar joint the medial
side of the head of the radius articulates with the Radial Notch
(Lesser Sigmoid Cavity) of the ulna, and the cartilage covering
these areas is directly continuous with that which covers the
adjoining articular surfaces of the humero-radial and humero-
ulnar joints.

The transverse axis of the trochlea slants distally and
medially, and is therefore not at right angles to the long axis of
the humerus. The semilunar notch (greater sigmoid cavity)
is formed by the anterior surface of the olecranon and by the
proximal surface of the coronoid process. The transverse axis
of the latter forms an angle of less than 90° with the shaft of the
ulna, and so the long axis of the humerus and ulna meet at an
angle of less than 180° when the forearm is extended and supine.
This lateral angulation (Fig. 16) is termed the " Carrying
Angle," and it allows the supinated forearm to swing freely past
the pelvis. It is masked in flexion of the supinated forearm
and in pronation. The angles which the long axes of the
humerus and ulna make with the transverse axis of the elbow
are equal to one another. As a result, when the supinated
forearm is fully flexed, the anterior surfaces of the arm and
forearm are accurately applied to one another. But, when
the supinated forearm is fully flexed (the arm being by the side),
the palm of the hand lies over the medial half of the clavicle
and not over the point of the shoulder, owing to the existing
medial rotation of the humerus (p. 44). To obtain the correct
alignment of the arm and to reproduce accurately the carrying
angle following fractures into the joint, the limb is adjusted

52 THE SUPERIOR EXTREMITY

with the arm by the side, the forearm fully flexed but not
quite fully supinated, and the palm in front of the medial half
of the clavicle.

The Capsule is attached on the anterior aspect of the
humerus to the proximal borders of the coronoid and radial

FIG. 1 6. — Normal Elbow of an Adult Female. Antero-posterior View. The
carrying angle is well shown. The increased density of the shadow in
the region of the trochlea is caused by the olecranon.

fossae and to the bases of the epicondyles. Posteriorly, it is
attached to the floor of the olecranon fossa, and to its sides
as far as the bases of the epicondyles. On the ulna it is attached
to the margins of the semilunar notch, except at the radial
notch. On the lateral aspect of the joint it blends with the
annular ligament.

THE REGION OF THE ELBOW

53

The Annular (Orbicular) Ligament surrounds the head of
the radius and is attached to the anterior and posterior
extremities of the radial notch. Its proximal border blends
with the capsule of the elbow, but its distal margin is not attached
to bone, and therefore the distal part of the capsule of the elbow
and proximal radio-ulnar joints is incomplete. Through the
gap left between the neck of the radius and the distal border
of the annular ligament the synovial membrane pouches distally
for a varying distance (Fig. 17).

The Anterior and Posterior Ligaments of the elbow are

paM:
m®£- •'•^^:'

Medial epicondyle-jf-'fif' - •
Epiphyseal lines

Distal epiphysis

of humerus

Ulnar col lateral -

ligament

Radial collateral
ligament

Annular ligament
Head of radius
Epiphyseal line

Protrusion of
ynovial membrane

FIG. 17. — Frontal Section through the Elbow and Proximal
Radio-Ulnar Joints.

Light blue = articular cartilage.
Striped blue = ligaments.

Green = periosteum.

Red = synovial membrane.

simply thickenings of the capsule in front and behind. They
do not possess great strength, but they are supported by the
tendons of the brachialis and the triceps respectively.

The Radial Collateral (External Lateral) Ligament is
narrow at its attachment to the lateral epicondyle but is wider
distally, where it blends with the annular ligament.

The Ulnar Collateral (Internal Lateral) Ligament is
attached to the distal aspect of the medial epicondyle. Its
anterior fibres pass to the medial border of the coronoid process
and its posterior fibres to the medial border of the olecranon,
while the intermediate fibres are attached to a strong transverse
band which bridges the interval between the two processes.

4a

54

THE SUPERIOR EXTREMITY

The Synovial Membrane is attached to the margins of the
articular cartilages of the humerus, ulna, and radius. It then
covers the adjacent bone as far as the attachment of the fibrous
capsule, on to which it is reflected. At the distal border of the
annular ligament of the radius the membrane pouches down-
wards for a short distance around the neck of the bone. Little
pads of fat fill up the olecranon, coronoid, and radial fossae,,

Posterior ligament
Pad of fat

Anterior ligament

Epiphyseal line

Pad of fat

Trochlea of
humerus

Triceps tend
Bursa under triceps

Olecranon V"Y"
Epiphyseal line X—

Olecranon bursa

FIG. 1 8.— Sagittal Section through the Elbow Joint. The synovial mem-
brane lining the joint is shown in red, the articular cartilage in light
blue, and the periosteum in green. The pads of fat, though intra-
capsular, are extra-synovial.

but although they are intra-capsular they are covered by the
synovial membrane and therefore remain extra-synovial (Fig.
1 8). When these fatty pads hypertrophy (lipoma arborescens),
portions of them may project into the joint , but they are still
covered by a layer of synovial membrane.

The Nerve Supply of the joint is derived from branches of
the Ulnar, Median, Radial (Musculo-spiral), and Musculo-
cutaneous nerves.

The presence of fluid in the joint is apparent first on either
side of the tendon of the triceps, owing to the weakness of the

THE REGION OF THE ELBOW 55

posterior part of the capsule, and, subsequently, the dimple
proximal to the head of the radius becomes obliterated. The
deep fascia on the front of the elbow and the lacertus fibrosus
(bicipital fascia) are exceptionally strong, and therefore, if

FIG. 19. — Elbow of Child, aged four. Lateral View. The centre of ossifica-
tion for the capitulum is the only secondary centre present. It lies on a
plane anterior to the long axis of the humerus. A tuberculous focus is
seen in the proximal part of the shaft of the ulna.

sinuses develop in connection with the joint, they will usually
be found on one or other side of the triceps tendon.

The elbow-joint may be aspirated by inserting a trochar
from the lateral side, at right angles to the limb, immediately
proximal to the head of the radius.

Ossification of the Distal Extremity of the Humerus.—
In the infant the whole of the distal extremity of the humerus

56 THE SUPERIOR EXTREMITY

is cartilaginous. During the second or third year a secondary
centre appears for the Capitulum and lateral part of the Trochlea,
and this is followed, about the fifth year, by the centre for the
Medial Epicondyle. At this period the distal and medial part

FIG. 20. — Elbow Joint of Boy, aged fourteen. The centres of ossification
in the distal extremity of the humerus are well shown.

of the diaphysis grows distally, separating the Medial Epicondyle
from the rest of the Epiphysis (Fig. 17). During the eleventh
and twelfth years centres appear for the Lateral Epicondyle
and the remainder of the Trochlea. The true epiphysis consists
of the three lateral centres of ossification, which fuse with one
another at thirteen or fourteen, and it joins the shaft between

THE REGION OF THE ELBOW

57

the sixteenth and seventeenth years. The actual line of union
corresponds to the proximal margin of the articular cartilage
and laterally from the point at which the cartilage ceases, to a

FIG. 21. — Elbow of Child, aged five. The centres of ossification for the
capitulum and for the head of the radius can be recognised, but the
medial epicondyle has not yet begun to ossify.

point immediately proximal to the lateral epicondyle ; on the
medial side it coincides with the margin of the trochlea (Fig. 18).
The medial epicondylar epiphysis joins the diaphysis about one
year later.

58 THE SUPERIOR EXTREMITY

Ossification of the Proximal Extremity of the Ulna.—
The formation of the olecranon is due chiefly to the growth of
the diaphysis which occurs during childhood. A secondary
centre appears in the cartilaginous extremity about the eighth
or ninth year. It forms the proximal portion of the olecranon
(Fig. 1 8), but, as a rule, it takes no part in the formation of the
articular surface of the semilunar notch (greater sigmoid cavity).
It joins the shaft about the seventeenth year.

Dislocation of the elbow is common in childhood; because
the bony prominences, which in adults produce an osseously
strong joint, are only developing at that period.

Ossification of the Proximal Extremity of the Radius.—
In the cartilaginous proximal extremity of the radius a secondary
centre appears between four and five, and forms a disc-shaped
epiphysis, which joins the shaft between eighteen and twenty.
Until this centre begins to enlarge, there is relatively little
difference between the circumferences of the head and the neck
of the bone. This fact explains the frequency of subluxation
of the radius (p. 62) in little children.

The various epiphyses of the elbow have been described in
some detail, as a thorough knowledge of them is necessary for
the correct interpretation of radiograms of this region. It is not
uncommon for the clear area of epiphyseal cartilage to be mis-
taken for the line of a fracture, if there is any history of injury ;
and the olecranon has been cut down upon owing to this error.

Separation of the Epiphysis at the distal end of the
humerus is the commonest of the more severe injuries of the
elbow region which occur during childhood and adolescence.
It may be complicated by fracture across the distal and medial
portion of the diaphysis. The displacement of the distal
fragment is usually backwards, and, owing to the exceedingly
strong attachment of periosteum to epiphyseal cartilage, the
periosteum is stripped up from the posterior aspect of the distal
part of the diaphysis for a varying distance. Unless the
replacement is accurate, the stripped periosteum forms a new
shaft to the humerus posterior to the existing one, which remains
as a prominent exostosis (Fig. 22), and subsequently interferes
with flexion by impinging on the coronoid process. As the
cartilaginous extremity is translucent to the X-rays, there may
be great difficulty in diagnosing this condition in children of less
than three years of age, i.e. before the secondary ossific centres
are present.

THE REGION OF THE ELBOW

59

Spread of Tuberculous Osteo - Myelitis in the Elbow
Region. — A focus of tubercle situated in the growing region of
the diaphysis of the distal extremity of the humerus is intra-
capsular. It may spread (i) towards the medullary cavity ;

FIG. 22. — Elbow of Child, aged five. Lateral View. The condition shown
is subsequent to separation of the distal humeral epiphysis, in which the
periosteum had been stripped up from the posterior surface of the
diaphysis. Owing to malposition of the fragments, a new shaft has been
formed on a posterior plane.

(2) distally, through the epiphyseal cartilage, into the epiphysis,
to erupt subsequently through the articular cartilage into the
joint ; or (3) if the focus increases in all directions, it will, in
spite of the reaction of the periosteum, perforate that membrane
where it lines one of the humeral fossae. The disease is then
intra-capsular but extra-synovial, and is in direct relation to

6o THE SUPERIOR EXTREMITY

the extra -sy no vial pads of fat (p. 54). It rapidly involves
the sy no vial membrane and attacks the joint. The last-
mentioned is the usual direction of spread (Stiles). When a
focus is recognised before it has penetrated the periosteum, the
distal part of the diaphysis may be resected subperiosteally,
without the joint being opened.

Surgical Approach to the Distal Part of the Humerus. —
In subperiosteal resection of the distal part of the shaft of the
humerus for tuberculous disease, the bone is approached on the
postero-lateral aspect of the arm. The incision extends from
just below the radial (musculo-spiral) groove to the lateral
epicondyle. The medial head of the triceps is split and the
bone is exposed. After the periosteum has been separated,
the humerus is cut through at a level proximal to the disease,
and the distal part of the diaphysis is wrenched out. The bone
tears away from the epiphyseal cartilage, which is left attached
to the epiphysis. Although the capsule is attached to the
periosteum beyond the epiphyseal line, the elbow-joint is not
opened because the periosteum is firmly attached to the
epiphyseal cartilage.

When a tuberculous focus occurs in the Proximal Extremity
of the Radial Diaphysis, it is intra-capsular . Any extension
of the disease through the periosteum of the neck will certainly
infect the synovial membrane of the elbow-joint, on account
of the relations which these structures bear to one another
(Fig. 17). Extension in a distal direction will involve the shaft.
(See p. 75 for resection of proximal part of radius.)

A tuberculous focus in the Proximal End of the Ulna is
extra-capsular. It may spread (i) forwards through the articular
cartilage into the joint ; (2) distally into the shaft, or (3) it may
perforate the periosteum on the lateral or medial side of the
bone and infect the soft parts. The last mentioned is the
commonest direction of spread.

The proximal end of the ulna is unsuitable for complete sub-
periosteal resection as, by removal of the shaft and semilunar
notch (greater sigmoid cavity), the elbow-joint is widely opened.

Dislocation Of the Elbow.— (a) Posterior.— This injury
results from a fall on the hand, the arm being abducted at the
shoulder and extended at the elbow. The line of force passes
upwards behind the transverse axis of the elbow-joint, and, as
a result, the forearm is hyper-extended. All the ligaments
give way, except the annular (orbicular), and the distal extremity

THE REGION OF THE ELBOW 61

of the humerus slips forwards out of the semilunar notch. The
coronoid process comes to rest in the olecranon fossa ; the head
of the radius lies behind the lateral epicondyle ; and the distal
end of the humerus sinks into the cubital fossa. The arm and
forearm meet at an angle of about 120°,, but in old-standing
cases the angle becomes less pronounced owing to the constant
traction of the triceps. The relations of the epicondyles to one
another are unchanged, but their relations to the other bony
points undergo considerable alteration.

(b) Anterior. — This rare dislocation results from violence,
applied to the olecranon from behind when the elbow is flexed.
The triceps is ruptured and the radius and ulna pass forwards,
the forearm being flexed by the brachialis and the biceps. All
the ligaments except the annular (orbicular) are torn, and the
muscles arising from the epicondyles may be injured. Compared
with the sound limb, there is an increase in the distance between
the lateral epicondyle of the humerus and the styloid process
of the radius.

An incomplete variety of this dislocation occurs when the
injury is complicated by fracture of the olecranon. The small
fragment remains in contact with the trochlea, but the remainder
of the ulna and the radius pass forwards in front of the distal
end of the humerus.

(c) Lateral and (d) Medial dislocations occur from falls
upon the pronated, outstretched hand. The direction of the
displacement depends on whether the line of force is lateral or
medial to the mid-point of the transverse axis of the elbow.

The lateral dislocation may be complete, and, if so, all the
ligaments, except the annular, are ruptured. More commonly
the semilunar notch does not entirely leave the trochlea, and
the dislocation is consequently incomplete.

The medial dislocation is always incomplete, as the head of
the radius remains partially in contact with the capitulum,
though at a different angle, as the long axis of the bone is now
directed distally and medially.

Divergent dislocations can occur only after rupture of the
annular (orbicular) ligament. They may be either antero-
posterior, the radius passing forwards and the ulna backwards,
or they may be horizontal, the radius being displaced laterally
and the ulna medially.

Reduction of the posterior dislocation may be performed
by traction on the forearm and counter-extension of the arm.

62 THE SUPERIOR EXTREMITY

As soon as the coronoid process is drawn past the distal surface
of the trochlea, the forearm is flexed, as the displacement will
not recur with the elbow in this position. If the coronoid
process hitches in the olecranon fossa, the forearm may be
hyper-extended,, and, by using the tip of the olecranon as a
fulcrum against the distal end of the humerus, the coronoid is
lifted out of the olecranon fossa. It can then be drawn distally
by traction.

In children, reduction is easily obtained (p. 58) if the surgeon
grasps the arm just proximal to the epicondyles in such a way
that he can exert the pressure of both thumbs to push the
olecranon downwards.

The spasm of the brachialis assists in the replacement, as
soon as the tension of the triceps is overcome.

Complications. — The Ulnar Nerve may be stretched or
bruised at the time of dislocation, especially if the medial
epicondyle is broken off (p. 63).

Fracture of the Coronoid Process may complicate the
posterior dislocation. Reduction is easy, but the displacement
readily recurs. The injury may be mistaken for a supracondylar
fracture of the humerus, unless the relations of the bony points
are' carefully studied.

Fracture of the Epicondyles (p. 63).

Myositis ossificans in the tendon of the brachialis is a
complication which not uncommonly follows dislocation of the
elbow. The osseous deposit interferes with complete flexion
and may or may not remain permanently.

Subluxation of the Radius (p. 58) is produced by sudden
traction on the hand or wrist. It is probable that only a part
of the head of the radius slips out of the annular (orbicular)
ligament ; otherwise reduction would be difficult to obtain.
When the accident occurs, the forearm is in the position of
pronation and the greatest strain is thrown, through the radius,
on to the lateral part of the annular ligament. This oblique
strain drags the postero-lateral part of the head of the radius
through the ligament, leaving the medial half of the head within
the joint. Complete downward subluxation is prevented by
the interosseous membrane and the ligaments of the distal
radio-ulnar joint, and can occur only when these ligaments are
injured. The forcible supination, carried out by the surgeon,
screws the half-dislocated head back into place again.

Fractures around the Elbow-Joint.— The distal end

THE REGION OF THE ELBOW 63

of the humerus is weakened by the grooving of the trochlea and
by the olecranon and coronoid fossae. It has to withstand the
force transmitted through the forearm from falls upon the hand,
and in consequence fractures in this situation are very common.

In children, the injury may take the form of a Separation
of the Distal Epiphysis of the Humerus. In adults, the
supracondylar fracture of the shaft frequently radiates through
one of the fossae into the joint, giving rise to the so-called T- or
Y-shaped fracture.

The medial epicondyle may be fractured without other
injuries. It is displaced distally and forwards by the attached
flexor and pronator muscles. Sometimes the line of this fracture
is oblique and includes a portion of the trochlea in addition,
consequently involving the joint. Through faulty apposition
the medial epicondyle may be displaced proximally, changing
the transverse axis of the trochlea (p. 51), and subsequently
leading to the condition of cubitus varus.

This injury may involve the ulnar nerve, causing neuritis
and progressive paresis of the muscles which it supplies (p. 104).
Occasionally the symptoms do not appear till many years later,
and evidence of injury, of which there is often no history, is
obtained only by the X-rays.

Injury to the lateral epicondyle may lead in the same way
to the condition of cubitus valgus (see Carrying Angle, p. 51).

Fracture of the Olecranon Process. — The small, proximal
fragment usually includes the proximal half of the semilunar
notch, and, consequently, the joint cavity of the elbow is
involved (Fig. 18). The swelling, which is partly due to the
violence, is increased by haemorrhagic extravasation into the
joint, and it may press upon the superficial veins, producing
cedema of the forearm and hand. There may be little or no
separation of the fragments, in which case they are kept in
position by the periosteum, the ulnar collateral (internal lateral)
ligament of the elbow, the anconaeus, and the common ulnar
aponeurosis. When wide separation occurs, the proximal
fragment is drawn proximally and backwards by the triceps,
and difficulty is experienced in keeping the ends in good
apposition. On this account the surgeon frequently has recourse
to the operation of wiring. The fragments can be brought
together by two wires — one vertical, the other transverse —
without interfering with the articular surface (Fig. 23).

Fracture of the Neck of the Radius is a rare accident,

64 THE SUPERIOR EXTREMITY

and it is difficult to treat owing to the lack of fixation of the
head (p. 53); which may become a loose body in the elbow-joint.
On pronation and supination, the head of the radius does not
rotate in the annular ligament,, and the muscles are thrown into
spasm. Owing to non-union or to faulty union, movements of
the elbow may be so restricted that excision of the head of the

FIG. 23. — Elbow of an Adult Male, showing a Fracture of the Olecranon,
wired in Two Planes. Note that the wires do not invade the joint cavity.

bone is rendered necessary. It may be approached by a
longitudinal incision over the interval between the anconaeus
and the extensor carpi ulnaris (Fig. 26).

Many of the fractures in this region are both intra- and
extra-capsular, and the haemorrhage and effusion into the joint
render their diagnosis difficult, even with the assistance of the
X-rays.

Surgical Approach to the Elbow- Joint. — Kocher's lateral

THE FOREARM AND WRIST 65

J -shaped incision is probably the best, since it is planned so as
to do least damage and yet gives good preliminary exposure.
Proximally, the incision lies immediately behind the lateral
intermuscular septum and the radial collateral (external lateral)
ligament, and, below, it follows the distal border of the anconseus
to the ulna. The annular ligament is cut through on its lateral
aspect and the joint is opened.

If the subperiosteal method of resection is adopted, large
portions of the removed shafts will be reproduced. Some
shortening of the limb may follow, but growth is most active
and most prolonged at the shoulder and wrist, and consequently,
the results of removal of the epiphyses at the elbow are not so
serious as might be expected. The flap, which consists of the
skin, fascia, triceps, and anconseus, is elevated subperiosteally
from the humerus and the ulna until the ulnar collateral liga-
ment is freed. After the radial collateral ligament has been
dealt with similarly, the olecranon is removed. In this way
the joint is widely exposed. In dealing with the neck of the
radius, care must be taken lest the deep branch of the radial
nerve (posterior interosseous nerve) should be injured in its
passage through the supinator (s. brevis), and the dependent
pouch of the synovial membrane in this situation (Fig. 17)
must be totally extirpated. The synovial membrane covering
the fatty pads (p. 54 ) which fill up the humeral fossae is also
completely removed. In this operation the ulnar nerve is not
exposed, if the subperiosteal excision is employed.

THE FOREARM AND WRIST.

Bony Landmarks.— The proximal part of the shaft of the
Radius is surrounded by muscles, but the distal part of its
lateral surface and most of its distal extremity can be
readily examined. The anterior border of its distal end
can be made out as a distinct ridge on the front of the forearm
about an inch from the thenar eminence. In the hollow
immediately proximal to this ridge the radial artery can be
felt pulsating, and it may be compressed backwards against
the bone. The radial ridge can be traced laterally till it joins
the sharp volar (anterior) margin of the bone. When the

5

66 THE SUPERIOR EXTREMITY

thumb is extended, the tendons of the abductor pollicis longus
(ext. oss. metacarp.) and the extensor pollicis brevis can be felt
on the radial side of the wrist, and when the tendons are relaxed,
the apex of the Styloid Process of the radius is found under
cover of them, half an inch distal to the radial ridge. A tubercle
(of Lister) is situated on the dorsal aspect of the distal end of
the radius, in the line of the cleft between the index and middle
fingers.

The Dorsal Border of the Ulna is subcutaneous throughout
its whole extent, and, in muscular subjects, its position is
indicated by a furrow. The Styloid Process of the Ulna can
be found by tracing the dorsal border distally. It is placed on
the postero-medial aspect of the head and lies from a quarter
to half an inch proximal to the styloid process of the radius.
It corresponds to the level of the wrist -joint. When the hand
is flexed, the rounded Head of the Ulna can be felt just proximal
to the level of the radial ridge by displacing the tendon of the
flexor carpi ulnaris either to the ulnar or to the radial side.
When the hand is prone, the lateral surface of the head stands
out prominently on the ulnar side of the back of the wrist.

The Tubercle of the Navicular (Scaphoid) is felt about
three-quarters of an inch distal to the radial ridge at the proximal
border of the thenar eminence. If the most distal skin crease
at the wrist is followed, it will be found to cross the tubercle
of the navicular, on the radial side, and the Pisiform Bone, on
the ulnar side. This latter bone is most easily identified by
allowing the hand to hang in a passively flexed position to
relax the flexor carpi ulnaris, as it may then be pinched between
the examining finger and thumb and made to glide on the os
triquetrum (cuneiform). The Hook of the Hamate (Unciform)
lies one finger's breadth distal to the pisiform and on a line with
the ulnar border of the ring finger. On deep palpation the
superficial division of the ulnar nerve may be rolled to and fro
over the prominence. The Ridge on the Os Multangulum
Majus (Trapezium) is placed immediately distal to the navicular
tubercle.

Muscular Landmarks. — The muscular mass inthe proximal
and lateral part of the forearm consists of the Brachio-Radialis
and the Extensor Carpi Radialis Longus and Brevis, which
arise from the lateral epicondylic ridge and the lateral epicondyle.
The medial margin of this group is indicated by a line drawn
from the tendon of the biceps to the styloid process of the

THE FOREARM AND WRIST

67

radius. When resistance is offered to flexion of the elbow,
the brachio-radialis stands out prominently on the lateral
aspect of the forearm.

The individual Flexor and Pronator muscles cannot be
clearly distinguished proximally, as they are closely bound
together by the deep fascia. Nearer the wrist, however, certain
of the tendons provide important surgical landmarks. The
largest and most prominent tendon is that of the Flexor Carpi
Radialis, which lies just medial to the navicular tubercle. In
flexion of the wrist the Palmaris Longus tendon, absent in
10 per cent, stands out on the ulnar side of the flexor carpi
radialis. It is the guide to the median nerve, which lies
immediately behind it, or to its radial side, in the distal part of
the forearm. The tendon of the Flexor Carpi Ulnaris can be
gripped between the fingers and thumb by inserting the fingers
on the medial border of the forearm opposite the distal end of
the ulna. It may then be traced to its insertion into the pisiform
bone.

A line drawn from the lateral epicondyle to the dorsal radial
tubercle demarcates the Radial Extensors of the Wrist from

Insertion
of deltoid

Head of radius Extensor carpi radialis longus

Lateral | | Dorsal interosse-
epicondyle . ! ous nerve Abductor

; ; : I Extensor carpi pollicis

radialis brevis longus

Radial nerve
Triceps, lateral head

Tendon of triceps

Olecrano

Head of ulna
: Extensor carpi ulnaris
; Dorsal border of ulna
! Flexor carpi ulnaris and
] flexor digitorum profundus
Anconoeus

FIG. 24. — Surface Landmarks on the Dorsal Aspect of the
Superior Extremity.

the Extensor Digitorum Communis. One inch from its
proximal extremity, it crosses the head of the radius, and at a
point two inches lower down, the dorsal interosseous nerve
emerges from the substance of the supinator (brevis). In its
distal third, the line is crossed obliquely by the muscular bellies
of the Abductor Pollicis Longus (Ext. Oss. Metacarp.) and
the Extensor Pollicis Brevis. These muscles lie superficial
to the radial extensor tendons of the wrist and are thrown into
relief on dorsi-flexion of the hand.

68 THE SUPERIOR EXTREMITY

On the lateral aspect of the wrist, a triangular depression is
visible when the thumb is extended. It is bounded antero-
laterally by the tendons of the Abductor Pollicis Longus and
the Extensor Pollicis Brevis and dorso-medially by the
Extensor Pollicis Longus. The floor of this fossa is crossed
obliquely by the second part of the radial artery (p. 92).

On the back of the wrist the tendons of the Extensor Carpi
Radialis Longus and Brevis can be seen when the fist is tightly
clenched, and they can be traced to their insertions into the
bases of the second and third metacarpal bones respectively.

Muscles of the Forearm and their Relations to
Fractures. — The superficial group of flexors and pronators
arises mainly from the medial epicondyle of the humerus. They
pass with varying degrees of obliquity down the forearm and
are all, with the exception of the flexor carpi ulnaris, supplied
by branches given off from the trunk of the Median Nerve
(C. 6), just distal to the elbow-joint.

The Pronator Teres, which has in addition a deep head of
origin from the coronoid process, is the most lateral and most
obliquely directed of this group. It is inserted into the middle
of the lateral surface of the radius and is thus a powerful pronator
of the forearm, while it is also a flexor of the elbow. In tennis-
players this muscle is frequently overstretched or strained.

Fractures of the Bones of the Forearm.— Fractures
from indirect violence may affect both bones or the radius alone.
They occur from falls on the hand, and only a small part of the
shock is directly transmitted to the ulna. The greater part is
communicated to the expanded distal end of the radius and
passes upwards to the humerus. Only a small degree of the
shock is transmitted from the radius to the ulna by the
interosseous membrane, the fibres of which are mainly directed
distally and medially. Fracture of the shaft of the ulna alone
is always due to direct violence and tends to be compound, as
the dorsal border of the bone is subcutaneous in its whole
extent.

In Fractures between the Radial (Bicipital) Tuberosity
and the Insertion of the Pronator Teres, the small proximal
fragment is flexed and supinated by the biceps. The distal
fragment is pronated by the pronator muscles and its proximal
end is tilted towards the ulna by the brachio-radialis and the
pronator teres. The proximal fragment is difficult to control
owing to its small size, and it is necessary to bring the distal

THE FOREARM AND WRIST 69

fragment into line with it by flexing the elbow and supinating
the hand.

In Fractures immediately Distal to the Insertion of the
Pronator Teres, the proximal fragment is pronated and slightly
flexed. The supinating action of the biceps is counteracted
by the pronator teres, which acts at a greater mechanical
advantage. The distal fragment is pronated by the pronator
quadratus, and its proximal end is tilted towards the ulna as
in the previous fracture. In this case the proximal fragment
is long enough to be controlled,, and the forearm is put up in the
mid-prone position, since the distance between the ulna and
radius is normally greatest in this position. Dinar flexion of
the hand helps to tilt the proximal end of the distal fragment
away from the ulna.

The Superficial Muscles of the Forearm.— The Flexor carpiradialis and
Palmaris longus both become tendinous about the middle of the forearm.
The palmaris longus tendon is rather longer and considerably narrower
than that of the flexor carpi radialis. Both muscles, when acting with
their groups, are powerful flexors of the wrist and weak flexors of the
elbow. When the flexor carpi radialis acts alone, it produces flexion and
radial deviation at the wrist ; when it acts along with the radial extensors,
radial deviation alone takes place.

The Flexor digitorum sublimis (p. 84) lies deep to the preceding tendons
and partly to their ulnar side. The individual tendons arise in the distal
third of the forearm, and pass behind the transverse carpal (anterior annular)
ligament. It is primarily a flexor of the proximal inter-phalangeal joints,
and secondarily a flexor of the metacarpo-phalangeal, wrist, and elbow-
joints.

The Flexor carpi ulnaris (p. 67) is the most medially placed muscle of this
group, and is supplied by the ulnar nerve (C. 8 and T. i). When acting
with its group, it helps to flex the wrist and elbow joints, but, when acting
with the extensor carpi ulnaris, it produces ulnar deviation of the hand.

Ulnar Nerve.— The course of the Ulnar Nerve may be
indicated by drawing a line from the medial epicondyle to
the lateral margin of the pisiform. In the proximal part of the
forearm the nerve is almost subcutaneous and may be rolled
to and fro against the ulna. It can be exposed by a vertical
incision through the skin and fascia behind the medial epicondyle,
and is found in contact with the medial side of the elbow-joint.

As the result of sudden violent flexion of the elbow, the deep
fascia over it is sometimes torn and the ulnar nerve slips forwards
round the medial epicondyle. This dislocation of the nerve
may require operative interference.

After supplying the joint, the ulnar nerve passes between
the two heads of the flexor carpi ulnaris and almost immediately
gives off branches to supply that muscle and the medial part of

THE SUPERIOR EXTREMITY

Triceps, medial head

Median nerve
Brachialis

Brachial artery
Ulnar artery -i

Pronator teres
Flexor carpi radialis

Palmaris longus
Flexor carpi ulnaris

Ulnar artery and nerve -
Transverse carpal ligament

Biceps

Lacertus fibr

Brachio-radialis
Radial artery

Supinator

Course of superficial
division of radial nerve

Flexor digitorum sublimis

Flexor pollicis longus
Radial artery

Extensor pollicis brevis
Abductor pollicis longus

FIG. 25. — The Anterior Aspect of the Forearm, after the removal of all the
Structures down to and including the Deep Fascia. The courses taken
by the nerves and arteries are indicated by the interrupted lines.

THE FOREARM AND WRIST 71

the flexor digitorum profundus. It runs downwards in front
of the latter and it is covered by the flexor carpi ulnaris in the
proximal two-thirds of the forearm. Distally it again becomes
superficial, lying between the most medial tendon of the flexor
digitorum sublimis, on the radial side, and the tendon of the
flexor carpi ulnaris, on the ulnar side. At the junction of the
proximal and middle thirds of the forearm, it becomes associated
with the ulnar artery, which lies close to its lateral side through-
out the remainder of their course in this region.

About three inches from the pisiform, the ulnar nerve gives
off palmar (p. 82) and dorsal cutaneous branches. The latter
passes backwards below the styloid process of the ulna, crosses
the medial surface of the os triquetrum (cuneiform) and gains
the dorsum of the hand, where it supplies the little finger and
the ulnar side of the ring finger (p. 72). This nerve runs some
risk of being cut in the ulnar incision for excision of the wrist.

Ulnar Artery. — In ligature of the ulnar artery in its
distal two-thirds, the incision should be made in the line of the
ulnar nerve. In the middle third, the flexor carpi ulnaris,
which overlies it, must be retracted to the medial side. The
course of the proximal third is indicated by a line drawn from
the termination of the brachial artery (p. 42) to the point
where the ulnar artery becomes associated with the ulnar nerve.
As it lies deeply under cover of the superficial group of muscles
and is crossed close to its origin by the median nerve, the artery
is rarely tied in this part of its course.

Branches. — The volar and dorsal ulnar recurrent (p. 44)
branches arise near the origin of the ulnar artery.

The Common Interosseous arises more distally and at once
divides into Volar (Anterior) and Dorsal branches. The former
runs distally in front of the interosseous membrane and
communicates with the volar carpal arch. It pierces the
membrane at the proximal border of the pronator quadratus
and anastomoses with the dorsal carpal arch and the dorsal
interosseous artery. The latter passes backwards proximal to
the membrane to supply the extensor muscles, and becomes
associated with the dorsal interosseous nerve.

The Superficial (Radial) Branch of the Radial (Musculo-
Spiral) Nerve arises in front of the lateral epicondyle under
cover of the brachio-radialis. It approaches the radial artery
and lies close to its lateral side in the middle third of the forearm.
About 3 1 inches from the styloid process of the radius the

56

72 THE SUPERIOR EXTREMITY

nerve leaves the artery to gain the dorsum of the wrist by
passing under cover of the brachio-radialis. Here it is joined
by communicating twigs from the dorsal branch of the musculo-
cutaneous and from the dorsal cutaneous nerve of the forearm
(lower external cutaneous branch of the musculo-spiral nerve).
It is a purely sensory nerve and terminates on the back of the
hand by supplying the skin on the dorsal aspects of the thumb,
index, and middle fingers, and the radial side of the ring finger.
Injuries to this nerve are discussed on p. 102.

The dorsal digital nerves do not reach the tips of the fingers
but end over the second phalanges ; the remainder of the dorsal
surface is supplied by the digital nerves of the palm.

Radial Artery. — The course of the radial artery may be
indicated by a line drawn from the termination of the brachial
artery (p. 42) to the navicular tubercle. In the proximal
two-thirds of its course it will be found under cover of the
brachio-radialis. In the proximal third it lies on the supinator,
and the superficial (radial) branch of the radial (musculo-spiral)
nerve approaches it from the lateral side. In the middle third it
lies on the pronator teres and the radial head of the flexor
digitorum sublimis while the nerve is close to its lateral side.
The distal third of the artery is subcutaneous and lies upon the
flexor pollicis longus and the radius (Fig. 25).

It gives off the radial recurrent (p. 43) near its origin, and
the superficial volar in the distal part of the forearm. The
latter runs through or over the short muscles of the thumb to
join the ulnar artery and complete the superficial palmar arch

(Fig. 30).

If the radial or ulnar artery is severed in more than one
place, all the cut ends must be tied, as the muscular branches
of the radial, ulnar, and volar (anterior) interosseous arteries
anastomose very freely throughout the forearm. When the
radial artery is wounded at the wrist, both ends must be ligatured,
owing to the free anastomosis in the hand (p. 86).

The Median Nerve, which enters the forearm between the
superficial and deep heads of the pronator teres (p. 68), can
be indicated by a line, drawn from a point midway between
the medial epicondyle and the biceps tendon to a point at the
wrist, slightly to the medial side of the tendon of the flexor
carpi radialis. It lies between the superficial and deep groups
of muscles, and is bound down to the deep surface of the flexor
digitorum sublimis. It supplies the superficial group (p. 69),

THE FOREARM AND WRIST 73

with the exception of the flexor carpi ulnaris, and by means of
its volar interosseous branch it supplies the deep muscles of the
front of the forearm. Injuries of the nerve are discussed on
p. 104.

The Deep Group of Muscles (Flexor pollicis longus, Flexor digitorum
profundus, and Pronator quadratus) is supplied by the volar interosseous branch
of the median nerve (C. 7, 8,. and T. i), with the exception of that portion
of the flexor digitorum profundus destined for the ring and little fingers,
which is supplied by the ulnar nerve (C. 8 and T. i).

The Extensor and Supinator Muscles. — The Brachio - radialis,
which is inserted into the distal part of the lateral surface of the radius, and
the Extensor carpi radialis longus are both supplied by the radial (musculo-
spiral) nerve (C. 5 and 6, C. 6 and 7, respectively). The former is a flexor
of the forearm ; in the movement of supination it assists until the mid-prone
position is reached, and it also assists pronation from the supine to the mid-
prone position.

The Supinator (S. brevis) winds round the posterior aspect of the proximal
part of the radius and is thus a powerful supinator. It is supplied by the
deep branch (posterior interosseous) of the radial (musculo-spiral) nerve (C. 6).

The Ancon&us covers the posterior aspect of the humero-radial joint,
and is supplied by a branch from the radial (musculo-spiral) nerve (C. 7 and 8).

The Superficial Group of Extensors arises from the distal part of the
anterior aspect of the lateral epicondyle of the humerus, and they are supplied
by the dorsal interosseous nerve (C. 6, 7, and 8).

This group comprises the Extensor carpi radialis brevis (p. 68), the Extensor
digitorum communis (p. 92), the Extensor digiti quinti proprius (p. 92), and
the Extensor carpi ulnaris (pp. 69, 81).

The Deep Group of Extensors arises from the dorsal surfaces of the
radius and ulna. They are all supplied by the dorsal interosseous nerve
(C. 6, 7, and 8).

The Abductor Pollicis Longus (extensor ossis metacarpi pollicis) (pp. 67, 75)
is inserted into the base of the metacarpal bone of the thumb. It extends
the thumb at the carpo-metacarpal joint.

The Extensor Pollicis Brevis and Longus (pp. 68, 75) are inserted into
the bases -of the first and second phalanges respectively. Primarily they
are extensors, but they also aid in abduction of the thumb.

The Extensor Indicis Proprius (p. 92).

The Dorsal Interosseous Nerve reaches the back of the
forearm by winding round the neck of the radius, in the substance
of the supinator (s. brevis), its course being at right angles to
the direction of the muscle fibres. On leaving the muscle
(p. 67) the nerve breaks up into branches which are distributed
to the remaining muscles on the back of the forearm.

Surgical Approach to the Bones of the Forearm.—
The Ulna may be exposed readily in any part of its extent by
incisions along its subcutaneous dorsal border.

The Radius may be exposed by incisions along the line
which separates the radial extensors of the wrist from the
extensor digitorum communis (p. 67).

Brachiulis

Brachio-radial

Extensor carpi radial
long

Extensor carpi radialis
brevis

Dorsal interosseous artery
and nerve

Extensor digitorum communi

Abductor pollicis longus
and extensor pollicis brevis "

Extensor pollicis longus J
Radius '

Dorsal carpal ligament

Extensor carpi radialis brevis

j
Radial artery /

First dorsal interosseou

Triceps

Head of radius
Anconaeus

Supinator

Dorsal border of ulna

Aponeurosis covering flexor
digitorum profunclus

Extensor carpi ulnaris

Extensor indicis proprius

Tendons of extensor dig. com.

Extensor digiti quinti
proprius

FIG. 26. — The Muscles on the Dorsal Aspect of the Forearm. The course
of the dorsal interosseous nerve, where it is not exposed to view, is
indicated by the interrupted line. The extensor digitorum communis,
digiti quinti proprius, and carpi ulnaris, have been divided and their
proximal parts elevated.

74

THE FOREARM AND WRIST 75

(a) Distal Third. — At its proximal end the incision exposes
the extensor pollicis brevis and the abductor pollicis longus
as they cross the tendons of the radial extensors of the wrist.
The extensor digitorum communis is exposed on the ulnar side
of the incision and is retracted medially. When the other
muscles and tendons mentioned above are retracted laterally,,
the distal part of the radius is exposed where it is devoid of
muscular attachments. In tuberculous osteo-myelitis the distal
part of the diaphysis may then be excised by dividing it proximal
to the level of the disease — the periosteum having been stripped
off — and by wrenching it away from the epiphyseal cartilage,
which remains attached to the epiphysis. The capsule of the
wrist joint is uninjured (Fig. 27).

(b) Middle Third. — The extensor pollicis brevis and the
abductor pollicis longus are exposed at the distal end of the
wound and are retracted distally and to the ulnar side. The
radial extensors of the wrist are retracted laterally, and the
bone is exposed between the origin of the abductor longus and
the insertion of the pronator teres.

(c) Head and Proximal Third. — When the extensor digitorum
communis is separated from the radial extensors of the wrist at
this level the supinator is exposed and must be divided below
and parallel to the dorsal interosseous nerve (p. 73). In
subperiosteal resection of this part of the radius for tuberculous
osteo-myelitis, the bone is cut through distal to the level of
the disease and the proximal part is wrenched away. The
cartilaginous head of the radius, with the epiphysis if it has
developed, is wrenched away with the shaft, as it is attached
only to the synovial membrane of the elbow-joint and possesses
no special ligamentous connections (Fig. 17). In this resection,
therefore, the cavity of the elbow-joint is widely opened.

The Distal Radio-Ulnar Joint.— The ulna is excluded
from the wrist-joint by a triangular fibro-cartilage — the articular
disc — which is attached by its apex to the base of the styloid
process of the ulna and by its base to the medial margin of the
distal end of the radius. The capsule is weak and loose, to permit
of pronation and supination, and the synovial membrane bulges
proximally between the two bones beyond the level of the distal
epiphyseal lines. Occasionally the articular disc is perforated,
and the synovial membrane becomes continuous with that of
the wrist-joint.

The Radio-Carpal Joint or Wrist- Joint.— The proximal

76 THE SUPERIOR EXTREMITY

surface of the proximal row of carpal bones forms a surface
which is convex from side to side and fits into a correspondingly
concave surface provided by the carpal aspect of the radius
and the articular disc. In this way radial and ulnar deviation
of the hand are rendered possible. The capsule is strengthened
by:

(i) .The Volar and (2) Dorsal Radio -Carpal Ligaments,
which are attached to the margins of the articular surfaces ;
they are weak bands., but they receive additional support from
the flexor and extensor tendons.

FIG. 27. — Section through the Carpus, to show the various Joint Cavities.

Light blue = articular cartilage. Green = periosteum.

Striped blue = ligaments. Red = synovial membrane.

(3) The Radial Collateral (External Lateral) Ligament
passes from the tip of the radial styloid to the lateral surface of
the navicular and is crossed by the second part of the radial
artery.

(4) The Ulnar Collateral (Internal) Ligament is attached
to the tip of the ulnar styloid and to the medial side of the
triquetrate (cuneiform) bone. It is on these collateral ligaments
that the strength of the joint depends.

The Synovial Membrane lines the interior of the capsule
closely ; it requires no special description.

Aspiration of the joint may be carried out immediately

THE FOREARM AND WRIST 77

distal to the tip of the styloid process of the ulna between the
extensor and flexor carpi ulnaris tendons.

Colles' Fracture occurs from a fall on the outstretched
hand. According to Chiene, the forearm is at an angle of less
than 60° to the horizontal when the palm of the hand strikes the
ground. The line of force cuts through the distal end of the
radius instead of passing along the bone, as it does if the forearm
is at an angle of more than 60° to the ground when the injury
occurs. Impaction of the proximal fragment into the distal
is not uncommon, as the fracture is transverse and occurs
through the spongy tissue of the distal end of the bone. The
line of force drives the distal fragment backwards and tends
to thrust it proximally, but the medial edge of the distal end
of the radius is attached to the ulna by the triangular articular
disc (p. 75), which slips backwards over the head of the latter
bone. The styloid process of the radius swings round the arc
of a circle whose radius is the length of the triangular articular
disc, together with the width of the lower end of the radius.
In this way the hand is deviated to the radial side, and the
displacement becomes three-fold. When the styloid processes
are compared (p. 66), they are found to be on the same level or
the radial is the more proximal.

If the ulnar styloid also is fractured, then the displacement
is backwards and upwards, but the upward displacement is
proportionately greater than in the typical Colles' fracture.
Smith's Fracture (reversed Colles') occurs from a fall on the
back of the hand, the wrist being flexed. The line of force cuts
through the anterior surface of the distal end of the radius and
the distal fragment is thrust forwards and proximally. The
hand is deviated to the radial side as in Colles' fracture and
for the same reason.

Ossification of the Distal Ends of the Radius and Ulna. —
Secondary centres for the distal ends of the Radius and Ulna
appear about the third and sixth years, respectively. The
distal epiphyses of both bones include the styloid processes
and the articular areas. Growth continues longer in the wrist
region than it does at the elbow, and the distal epiphyses do
not unite till between twenty and twenty-four.

Separation of the distal epiphyses of the radius and ulna
may occur between the ages of seven and twenty. Owing to
the line of attachment of the capsule of the wrist (p. 76), this
injury does not open into the joint.

y8 THE SUPERIOR EXTREMITY

Owing to trauma or disease, growth may cease prematurely
in one bone, but not in the other. As the healthy bone increases

FIG. 28. — Carpus of an Adolescent, aged sixteen. The centres of ossification
for all the carpal bones are present, but those for the os multangulum minus
and the pisiform are obscured by the os multangulum majus and the os
triquetrum, respectively. Observe the epiphysis of the first metacarpal bone.

in length, the hand gradually becomes deviated to the affected
side.

Carpal Joints. — With the exception of the carpo-metacarpal

THE FOREARM AND WRIST 79

joint of the thumb (p. 84) and the joint between the pisiform
and the os triquetrum cuneiform), all the inter-carpal, carpo-
metacarpal, and inter-metacarpal joints have a common joint
cavity lined with a single synovial membrane. Their volar
(palmar) and dorsal ligaments are continuous with the corre-
sponding ligaments of the radio-carpal joint (p. 76).

Ossification of the Carpus. — At the end of the first year
centres appear for the capitate (os magnum) and hamate
(unciform) bones. These are followed by centres for the
triquetrate (cuneiform), third year ; the lunate (semilunar),
fifth year ; the greater multangular (trapezium), sixth year ;
the navicular (scaphoid), sixth year ; the lesser multangular
(trapezoid), seventh year ; and the pisiform about the tenth
year.

Spread of Tuberculous Disease in the Wrist Region.—
The capsules of the distal radio-ulnar and the radio-carpal
joints do not encroach on the diaphyses, and, consequently,
tuberculous disease in the distal ends of the diaphyses of the
radius and ulna is extra- cap sular . When it breaks out under
the periosteum, it does not commonly spread distally to the
joints, unless it erupts in the region where the synovial membrane
of the distal radio-ulnar joint pouches proximally between the
two bones (p. 75).

The carpal bones are really within the capsule of the wrist-
joint, and tuberculous disease arising in them is intra-capsular
and readily reaches the joint by penetrating the articular
cartilage. If the disease spreads forwards or backwards,
perforating the ligaments, the synovial sheaths of the tendons
become affected ; but a sympathetic effusion may occur into the
sheaths while the disease is still confined to the joint, and it
may set up adhesions, which limit the movements of the muscles
concerned.

Surgical Approach to the Wrist - Joint.— Pyogenic
infections of the wrist- joint tend to point on the dorsal aspect,
to the radial or ulnar side of the tendon of the extensor quinti
digiti proprius. An incision immediately to the ulnar side of
the tendon of the extensor carpi ulnaris affords the best drainage
when the forearm is subsequently placed in the mid -prone
position.

In extensive tuberculous disease the Dorso-Ulnar Incision
(Kocher) offers the best approach, and little damage is done to
the tendons if the subperiosteal or the subcortical method is

8o THE SUPERIOR EXTREMITY

adopted in elevating the dorsal ligaments of the wrist and
carpus. Through the space obtained by first excising the
triquetrate (cuneiform) bone, the surgeon is able to divide the
hook of the hamate. This process and the pisiform are left
behind whenever possible, as they provide attachments for
the muscles of the hypothenar eminence and for the transverse
carpal (anterior annular) ligament. The remainder of the
carpus may then be removed piecemeal, but, if practicable, the
greater multangular bone (trapezium), which gives attachment
to the transverse carpal ligament, is left behind. Further, the
separate carpo-metacarpal joint of the thumb, which is not neces-
sarily affected by the disease, is opened into when the greater
multangular bone is removed, and the subsequent movements
of the thumb (p. 84) are seriously restricted. After removal
of the carpus, the extremities of the radius, ulna, and metacarpals
may be dislocated into the wound and resected, if necessary.
The wrist is subsequently dorsi-flexed, lest the powerful flexors
should overstretch the weaker extensor muscles.

In Dislocation of the Capitate Bone (Os Magnum) the head of the
bone projects dorsally, opposite the base of the third metacarpal, and the
deformity is increased on flexion of the hand.

The Lunate (Semilunar) Bone may be dislocated forwards by
forcible extension of the hand. In this case the ulnar nerve may be injured.

The Navicular Bone may be fractured at its narrowest part when it
is driven against the distal end of the radius by the rounded head of the os
capitatum (os magnum). Forward displacement of the greater and lesser
multangular bones (trapezium and trapezoid) sometimes accompanies this
injury.

THE HAND.

Bony Landmarks.— The base of the First Metacarpal is
readily felt in the angle between the tendons of the extensor
pollicis brevis and longus, and the dorsal surface of its shaft
can also be felt, though it is somewhat obscured by the extensor
tendons.

In Bennetfs Fracture, which passes obliquely through the
base of the first metacarpal, the large, distal fragment is drawn
proximally and slightly backwards by the combined action of
the flexors and extensors of the thumb. The small, proximal
fragment, which generally includes a part of the ulnar side of
the shaft, suffers little displacement. Abnormal movement

THE HAND 81

and crepitus are difficult to obtain, as it is not easy to fix the
proximal fragment, owing to its small size. This fracture was
difficult to recognise before the introduction of X-rays and was
frequently mistaken for a sprain of the carpo-metacarpal joint.

The whole of the radial border and most of the dorsal surface
of the Second Metacarpal can be readily examined ; its enlarged
base forms a prominence on the back of the hand.

The dorsal surfaces of the Third, Fourth, and Fifth
Metacarpals are obscured by the extensor tendons, but the
Styloid Process on the base of the third can be felt about two
fingers' breadths directly distal to the dorsal radial tubercle
(p. 66) ; the tendon of the extensor carpi radialis brevis is
attached to it. On the ulnar border of the hand, the tendon
of the extensor carpi ulnaris can be traced to its insertion into
the base of the fifth metacarpal.

Fractures of the metacarpal bones, when produced by direct
violence, are transverse and show little displacement. When
they follow indirect violence, they tend to be oblique, and the
distal fragment is generally displaced proximally and backwards,
causing a slight shortening of the corresponding finger.

The prominences of the knuckles are produced by the heads
of the metacarpal bones. The dorsal groove corresponding to
each metacarpo-phalangeal joint lies one-third of an inch distal
to the head of each metacarpal. On the palmar aspect the
joint corresponds to the lower skin crease of the palm and lies
three-quarters of an inch from the edge of the web of the fingers.

The dorsal line of each proximal inter-phalangeal joint lies
one-sixth of an inch distal to the prominence of the head of the
first phalanx, and corresponds, on the palmar aspect, to the
most proximal skin crease at the joint. The dorsal line of
each distal inter-phalangeal joint lies one-twelfth of an inch
distal to the prominence formed by the head of the second
phalanx and corresponds, on the palmar surface, to the most
distal skin crease at the joint.

The Superficial Fascia of the palm is rendered extremely
tough by the presence of numerous fibrous septa, which connect
the deep surface of the skin to the palmar aponeurosis (deep
palmar fascia). On this account pus does not accumulate in
any quantity in this situation, but makes its way through the
cutis vera and collects under the epidermis as a purulent blister.
Over the terminal phalanges the superficial fascia forms fatty
pads, which are connected to the periosteum by fibrous septa.

82 THE SUPERIOR EXTREMITY

Superficial septic infection in this region, unless freely incised
at an early stage, is apt to spread along the septa and cause
suppurative periostitis. Ultimately, necrosis of the phalanx
occurs although sometimes the base of the bone, with the
attachment of the flexor profundus tendon, is left behind.

On the dor sum of the hand the superficial fascia is thin and
membranous. It contains most of the lymph vessels of the
fingers and an irregular venous network, which gives rise to the
basilic, median, and cephalic veins.

Superficial Vessels and Nerves. — The skin of the palm is
supplied, as far as the heads of the metacarpals, by palmar
cutaneous branches from the ulnar, median, and radial nerves.
The digital vessels (p. 86) and the digital nerves (p. 86), which
lie anterior to them, are situated in the superficial fascia on the
sides of the fingers, nearer the palmar than the dorsal surface.

The skin on the dorsum is supplied by the terminal part of
the superficial (radial) branch of the radial (musculo-spiral) nerve
(p. 71) and by the dorsal cutaneous branch of the ulnar (p. 71).

Lymph Vessels. — All the superficial lymph vessels of the
fingers and palm, save those of the proximal part which run up
the front of the forearm, pass to the dorsum of the hand, and
become associated with the superficial veins. They are joined
by the deep lymph vessels of the palm, which reach the dorsum
by passing across the distal border of the transverse head of
the adductor pollicis. This arrangement explains the frequency
with which oedema or even metastatic abscesses may occur on the
dorsum of the hand, following septic infection of the fingers or
palm.

Deep Fascia. — The deep fascia of the forearm fuses below
with the palmar surface of the Transverse Carpal (Anterior
Annular) Ligament, which is a strong fibrous band, situated
in the proximal part of the hand. It provides a retentive
apparatus for the flexor tendons, and is attached to the pisiform,
and the hook of the hamate (unciform) on the ulnar side, and
to the navicular tubercle and the ridge of the greater multangular
bone (trapezium) on the radial side. A short band of fibres
passes from the pisiform to fuse with the palmar surface of the
ligament and, under cover of it, the ulnar nerve and artery are
continued into the palm.

The deep fascia of the palm, which is termed the palmar
aponeurosis, consists of a strong central portion, and two weak
expansions which cover the muscles of the thenar and hypothenar

THE HAND

eminences respectively. The central portion is exceedingly
dense, and prevents the forward spread of pus or blood.
Proximally, it blends with the transverse carpal ligament ;
distally, it widens out and breaks up into four slips, which become
continuous with the fibrous digital sheaths.

On the palmar aspect of the fingers,, the deep fascia is
attached to the borders of the phalanges and to the inter-
phalangeal ligaments. On the terminal phalanx it is attached
to the palmar surface of the bone immediately beyond the
insertion of the tendon of the flexor digitorum profundus. In
this way it forms a fibrous sheath for the flexor tendons, which
lie in an osteo-fascial canal on the front of the fingers. The

Vinculum breve

Vinculum longum !

Insertion of flexor digitorum sublimis tendon |

Fibrous sheath |

Flexor digitorum sublimis tendon |

Flexor digitorum profundus tendon

FIG. 29. — Longitudinal Section through the Third Finger, to show the
arrangement of the Fibrous and Synovial Sheaths.

Light blue = articular cartilage. Green = periosteum.

Dark blue = ligaments. Red = synovial membrane.

sheath is thinner and weaker opposite the inter-phalangeal
joints, to allow of free flexion (Fig. 29).

In the early stages of Dupuytren's Contraction the
metacarpo-phalangeal joints, generally of the ring and little
finger, become flexed, owing to an interstitial fibrosis of the
medial part of the central portion of the palmar aponeurosis.
Later, the inter-phalangeal joints also become flexed, as the
fibrosis attacks the weak areas which are present in the fibrous
digital sheaths opposite the joints.

In Congenital Contraction of the Fingers, which also
affects the ring and little fingers, the metacarpo-phalangeal
joints are hyperextended and the inter-phalangeal joints are
flexed. This contraction, therefore, is not caused by the action
of the aponeurosis, but is suggestive of some functional in-
capacity of the lumbricals supplied by the ulnar nerve (p. 84).

Qa

84 THE SUPERIOR EXTREMITY

The Hypothenar Eminence is produced by the abductor, the opponens
and the flexor brevis digiti quinti. These muscles are all supplied by the deep
branch of the ulnar nerve (C. 8 and T. i), and their actions are sufficiently
described by their names. When pus forms in the hypothenar eminence, it
is localised to that area, as it is shut off from the central portion of the palm
by & fibrous septum, which passes backwards from the ulnar side of the central
portion of the palmar aponeurosis. In these cases the incision is made over
the ulnar side of the fifth metacarpal bone, dorsal to the pisiform. The
nerves of supply, which enter the muscles close to the pisiform, are not inter-
fered with by this incision, and no damage is done to the first digital branches
of the superficial volar arch and ulnar nerve, which run distally, in front of
the flexor digiti quinti brevis, to supply the ulnar side of the little finger.

The Thenar Eminence is formed by the abductor pollicis, the flexor
pollicis brevis, and the opponens pollicis, which lies deep to the preceding
two muscles. These three muscles lie to the radial side of the tendon of the
flexor pollicis longus, and are all supplied by the median nerve (C. 8 and T. i).
They are shut off from the central space of the palm by a fibrous septum,
which passes backwards from the radial border of the central portion of the
palmar aponeurosis. When pus forms amongst these muscles, it is very
definitely localised, and shows no tendency to spread backwards or medially.
The incision lies over the distal part of the first metacarpal and on the radial
side of the eminence, thus avoiding the nerves of supply, which enter the
muscles at their carpal ends, and the digital nerve to the radial side of the
thumb (Fig. 30).

Movements of the Thumb. — Flexion and extension are the only move-
ments which occur at the metacarpo-phalangeal and inter-phalangeal joints
of the thumb. The additional movements of abduction, adduction, and
opposition all take place at the carpo-metacarpal joint, where the os mult-
angulum majus (trapezium) articulates with the first metacarpal bone.
This joint possesses a special synovial membrane, distinct from the synovial
membrane of the neighbouring joints. Abduction and adduction occur in
an antero-posterior plane, and the former movement must not be confused
with true extension, which occurs in a medio-lateral plane.

The Central Portion of the Palm.— The tendons of
the flexor digitorum sublimis and profundus lie behind the
central portion of the palmar aponeurosis before they enter
the fibrous digital sheaths. Opposite the first phalanx each
sublimis tendon splits, to allow the corresponding profundus
tendon to pass on to be inserted into the base of the distal
phalanx. Under cover of the profundus tendon the two slips
of the sublimis tendon receive attachment to the borders of the
second phalanx.

The four Lumbrical Muscles arise from the tendons of the
flexor digitorum profundus in the palm, and are inserted into
the radial side of the dorsal extensor expansion (p. 92) and
the adjoining part of the first phalanx of the medial four digits.
They flex the fingers at the metacarpo-phalangeal joints, but
extend them at the inter-phalangeal joints, through the medium
of the extensor expansion. The lumbricals of the little and
ring fingers are supplied by the deep branch of the ulnar nerve

THE HAND 85

(C. 8 and T. i) ; those of the middle and index fingers, by the
median nerve (C. 8 and T. i).

The Ulnar Nerve divides into superficial and deep branches
opposite the hook of the hamate bone. The former supplies
digital branches to the little finger and to the ulnar side of the

Volar radial a. of index '-,,
Digital branch of median n.

A. princeps pollicis
Branch to muscles of thuml

4; — Digital arteries

Superficial volar
- arch

' Deep volar arch
" and deep branch

of ulnar nerve

Ulnar artery
Ulnar nerve

A. superficialis \O\BS

Os multangulum majus -^

Radial artery ~^|j
Median ne

FIG. 30. — The Positions of the Vessels and Nerves Relative to the Bones
of the Hand and Wrist.

ring finger. The latter supplies the muscles of the hypothenar
eminence and runs transversely across the palm to end in the
oblique head of the adductor pollicis. In its course it accom-
panies the deep volar arch (p. 92), and lies behind the
flexor tendons and in front of the interossei and the proximal
ends of the middle three metacarpals. In addition to the
muscles already mentioned, it supplies all the interossei, the

6ft

86 THE SUPERIOR EXTREMITY

transverse head of the adductor pollicis, and the medial two
lumbricals.

The Median Nerve enters the palm behind the transverse
carpal (anterior annular) ligament. At the lower border of
the ligament it breaks up into lateral and medial divisions.
The lateral division at once supplies the thenar muscles
(p. 84) and gives off digital branches to supply both sides of
the thumb and the radial side of the index ringer. The medial
division gives off two branches, which run to the second and
third clefts to supply the adjacent sides of the index, middle, and
ring fingers, and twigs to their dorsal apects (p. 72). The
digital branches of the radial side of the index finger and the
second cleft supply the first and second lumbricals respectively.

The Superficial Volar (Palmar) Arch is the continuation of
the ulnar artery into the palm. It runs obliquely, distally, and
laterally across the hook of the hamate to reach the mid-point
between the base of the middle finger and the distal skin crease
at the wrist. The mode of termination of the arch is very
variable, but it is always joined by a branch from the radial
artery (superficialis volse, princeps pollicis or radialis indicis),
and the anastomosis is so free that in wounds of the arch both
the cut ends require to be tied. The artery lies immediately
under cover of the central part of the palmar aponeurosis, and
it crosses in front of the flexor tendons and their sheaths and
the digital branches of the median nerve.

It gives off four Digital Branches. The first supplies the
ulnar side of the little finger (p. 84) ; the second passes to the
fourth cleft, and lies to the ulnar side of the fourth metacarpal
bone ; the third passes to the third cleft and lies to the radial
side of the same bone ; the fourth crosses the third metacarpal
bone to gain the second cleft. An incision can therefore be made
over the distal part of the fourth metacarpal bone, without injuring
the superficial volar arch or any of its digital branches (Fig. 30).

Synovial Sheaths of the Flexor Tendons. — As the flexor
tendons pass into the palm, they are invested with synovial
sheaths, which are arranged in a somewhat complicated manner.

The tendon of the flexor pollicis longus has a separate sheath,
which extends distally as far as its insertion and proximally for
an inch or more beyond the transverse carpal ligament. It
consists of a " visceral " layer, closely applied to the tendon,
and a parietal layer, which lines the walls of the space occupied
by the tendon. At both extremities of the sheath the parietal

THE HAND 87

layer is reflected on to the tendon to become continuous with
the " visceral " layer,, so that the two enclose an elongated
bursal space.

In the fcetus the tendon is invaginated into the synovial
bursa from behind, and at first possesses a " mesentery "
throughout its whole extent in the sheath. This complete
" mesentery " breaks down in places, but it persists as the liga-
mentum breve, a triangular fold attaching the terminal part of
the tendon to the floor of its canal, and as the ligamenta longa,
which connect it to the floor in two or three places at a more
proximal level (Fig. 29).

The tendons of the flexor digitorum sublimis and profundus

Transverse carpal ligament Tendons of flexor digitorum sublimis

Median nerve
Tendon of flexor {

pollicis longi

Tendon of flexor
carpi radial

Tendons of flexor digitorum profundus

FIG. 31.— Diagram of a Transverse Section through the Carpus, to show the
arrangement of the Synovial Sheaths.

are provided with a single large sheath (the common palmar
sheath), which extends proximally as far as that of the flexor
pollicis longus. Its distal limit is oblique, reaching a more
distal level on the ulnar than on the radial side. The most
medial part of the sheath is carried distally on the tendons of
the little finger to their insertions (Fig. 32).

Figure 31 represents a transverse section through the wrist
at the level of the transverse carpal ligament. From this it
will be seen that the tendons have been invaginated into the
common palmar sheath on its radial side, and have formed three
pouches — one in front of the sublimis, pre-tendinous pouch ; one
between the two groups of tendons, inter -tendinous pouch ; and
a third, between the profundus and the floor of the carpal tunnel,

6c

88 THE SUPERIOR EXTREMITY

retro-tendinous pouch. The open space at the ulnar side of the
sheath, with which all three pouches communicate freely, is
termed the ulnar bursa.

The median nerve is situated between the sheath of the
flexor pollicis longus and the common palmar sheath.

Digital Synovial Sheaths invest the flexor tendons as they
lie in their osteo-fascial canals on the front of the fingers. They
extend distally as far as the insertion of the profundus tendons,
and proximally for half an inch beyond the metacarpo-phalangeal
joints. Ligamenta longa and brevia are present as in the case
of the flexor pollicis longus (Fig. 29). The digital synovial
sheath of the little finger is directly continuous with the common
palmar sheath, but the others are definitely closed at their
proximal ends.

The following variations are described by Poirier.

1. The index tendon of the profundus possesses a separate palmar sheath,
80 per cent.

2. The flexor pollicis longus sheath communicates freely at its proximal
part with the common sheath, 50 per cent.

3. The digital sheath of the little finger fails to communicate with the
common sheath, 35 per cent.

4. The flexor pollicis longus sheath is in two separate parts, a digital and
a carpal, 5 per cent.

Pus in the Common Palmar Sheath. — The common
palmar sheath may be infected primarily by punctured wounds
of the palm or it may be involved secondarily, following a septic
infection either of the digital synovial sheath of the little finger
(Fig. 32) or of the middle palmar space (p. 90). Incisions into
the -proximal part of the sheath are made in the line of the ring
finger, and are limited distally by the distal skin crease at the
wrist. In this way no damage is done to the median nerve
which lies to the radial side of the incision or to the ulnar nerve
and artery, which lie to its medial side. Incisions into the distal
part of the sheath are made in the same line, but are limited
proximally by the distal border of the transverse carpal ligament
and distally by the superficial palmar arch. If the pus ruptures
the common palmar sheath and extends into the forearm, it
may be evacuated by incisions along the same line (Fig. 32).

Compound Palmar Ganglion. — This condition is a tuber-
culous synovitis affecting the common palmar sheath. It gives
rise to a dumb-bell-shaped swelling, which extends from the
distal part of the forearm into the palm, the constriction being
due to the transverse carpal ligament. Should a cold abscess

THE HAND 89

arise, the common palmar sheath may require to be excised,

Digital synovial sheath

Synovial sheath of
flex. poll. long.

Ridge on os multangulum majus •

Transverse carpal ligament ,

Tuberosity of naviculai

Common
" palmar sheath

Pisiform

FIG. 32. — The Synovial Sheaths of the Wrist and Hand. The positions of
various incisions for the evacuation of pus are also shown.

i and 2. Incisions into the common palmar sheath, placed between the median and
ulnar nerves.

3. Incision uniting i and 2.

4. Incision into the proximal part of the sheath of flexor pollicis longus. It is placed
between the radial artery and the median nerve.

5. Incision into the distal part of the sheath of flexor pollicis longus.

6. Incision into the thenar space.

7. Incision over terminal phalanx.

8. 9 and 10. Incisions into the digital sheaths. They lie opposite the shafts of the
phalanges.

though the operation usually results in some damage to the
median and ulnar nerves.

Deep Muscles of the Palm. — The adductor pollicis possesses a transverse

9o THE SUPERIOR EXTREMITY

and an oblique head, which are both supplied by the deep branch of the ulnar
nerve (C. 8). It forms a triangular sheet of muscle, with its base attached to the
third metacarpal bone and its apex to the base of the first phalanx of the thumb.
In the interval between the two heads the radial artery enters the palm.

The three volar {palmar) interossei, which arise from the metacarpal bones
of the fingers on which they act, adduct the little, ring, and index fingers to the
middle line of the hand. The four dorsal interossei abduct the ring, middle, and
index fingers from the same line. Both groups are supplied by the deep branch
of the ulnar nerve (C. 8 and T. i), and, in addition to the above actions, they
help to flex the fingers at the metacarpo-phalangeal joints and to extend them
at the inter-phalangeal joints, the latter by virtue of their partial insertion
into the dorsal extensor expansion.

Fascial Spaces of the Palm. — Behind the flexor tendons and the
lumbrical muscles, there exists a large fascial space, which is subdivided into
a Middle Palmar and a Thenar Space by a septum of fibrous tissue attached
to the third metacarpal bone (Kanavel). This septum is weakened at its
proximal end, but it is usually strong enough to prevent the spread of pus
from the one space to the other.

The Middle Palmar Space lies to the radial side of the hypothenar
eminence, from which it is completely separated by a fascial septum (p. 84).
It is bounded behind by the strong fascia which covers the interosseous
muscles in the third and fourth spaces, and in front by the tendons of the
middle, ring, and little fingers with their lumbrical muscles. This fascial
space may be primarily infected by punctured wounds or by compound
fractures of the third, fourth, and fifth metacarpals. It can be involved
secondarily to superficial infections of the same fingers, the spread occurring
along the sheath of the lumbrical muscle ; or it may be involved by direct
spread from the digital synovial sheaths of the third and fourth fingers,
the pus rupturing through the closed proximal end of the sheath. If not
evacuated, pus in the middle palmar space may spread distally to point at
the web of the fingers ; or it may spread proximally behind the tendons
into the forearm ; or, in neglected cases, it may pass backwards between
the metacarpal bones and infect the dorsal subaponeurotic space (p. 91).
Incisions into the space are made over the distal half of the fourth metacarpal
bone (p. 86), and the tendons of the ring finger are exposed at a point where
they have no synovial sheath. In this way the middle palmar space can be
reached without opening into the common palmar sheath, which is not
necessarily infected.

The Thenar space lies between the middle palmar space and the tendon
of the flexor pollicis longus. It is bounded behind by the adductor of the
thumb and in front by the tendons of the index finger and the first lumbrical
muscle. Primary infections of this space may occur through punctured
wounds, and, very rarely, through compound fracture of the second meta-
carpal, which is separated from it by the adductor muscle of the thumb.
Septic infections of the index finger may involve the space secondarily,
following the same routes as have been described above in connection with
the middle palmar space. Pus in the thenar space may spread backwards
between the two heads of the adductor muscle, or over the distal border of
the transverse head to point on the dorsal surface of the web of the thumb.
It may also pass proximally into the forearm or distally to the interval be-
tween the index and middle fingers. Incisions into the thenar space are made
over the distal half of the second metacarpal (Fig. 32), and " through and
through " drainage may be obtained in the space between the first and
second metacarpal bones.

The Dorsal Carpal (Posterior Annular) Ligament is a

THE HAND 91

thickened portion of the deep fascia on the back of the wrist.
It is attached to the volar (anterior) border and styloid process
of the radius, and it passes obliquely across the dorsum of the
wrist, to be attached to the styloid process of the ulna and the
medial border of the carpus. Septa unite its deep surface to
the dorsal aspect of the radius, and form complete osteo-fascial
tunnels for the extensor tendons.

Synovial Sheaths of Extensor Tendons.— Synovial sheaths
invest the extensor tendons as they lie under cover of the dorsal
carpal ligament. They extend for a short distance proximal
to the ligament and distally for an inch or more beyond it. Six
sheaths are present at the back of the wrist, and they surround
the tendons of : —

1. Abductor pollicis longus (Ext. oss. metacarp) and Ext. pollicis brevis.

2. Ext. carpi radialis longus and brevis.

3. Ext. pollicis longus. At the point where this tendon crosses the radial
extensors of the wrist, the two synovial sheaths communicate freely.

4. Ext. digitorum communis and indicis proprius.

5. Ext. digiti quinti proprius.

6. Ext. carpi ulnaris.

The characteristic " new leather creaking " of teno-synovitis
in this region is due to friction between the inflamed " visceral "
and parietal layers of the tendon sheaths. The tendons of the
radial extensors are most commonly affected.

Carpal Ganglion, which usually occurs in relation to the
tendons of the radial extensors of the wrist, may or may not be
continuous with their sheaths. According to some authorities
it may arise from a degeneration of the ligaments in this region
or from the bursae which are situated immediately beneath the
insertions of these tendons.

The Dorsal Subaponeurotic Space. — On the dorsum of the
hand the extensor tendons of the ringers are united to one
another by oblique bands in such a way as to form with the deep
fascia an aponeurotic sheet, which is attached, on each side,
to the borders of the second and fifth metacarpals. The dorsal
subaponeurotic space (Kanavel) lies between this sheet and the
dorsal surfaces of the medial four metacarpals and interosseous
muscles. Septic infection of the space is generally primary,
following wounds on the dorsum. It may be involved secondarily
to infections of the middle palmar space (p. 90), but it is never
infected from the thenar space (p. 90). When pus collects in
this situation it is limited distally at the metacarpo-phalangeal

92 THE SUPERIOR EXTREMITY

joints and proximally, at the bases of the metacarpal bones, by
fibrous partitions. On each side it is limited opposite the
borders of the second and fifth metacarpal bones. Incisions
through the aponeurosis are made between the tendons distally
and run transversely, so that they may be kept open by
the traction of the extensor tendons, thus ensuring good
drainage.

In infections of the middle palmar space, " through and
through " drainage is obtained through the fourth interosseous
space and the dorsal aponeurosis.

Insertion of the Digital Extensor Tendons. — The tendons
of the extensor digitorum communis form a strong expansion
on the dorsum of the knuckles and first phalanx, which fuses
with the dorsal surface of the capsule of the metacarpo-phalangeal
joint. Into this expansion are inserted the tendons of the
lumbricals and interossei. On the index and the little fingers
the expansion is strengthened by the tendons of the extensor
indicis and quinti digiti proprius, which blend with it. The
central portion of the expansion is inserted into the base of the
second phalanx, while the collateral portions pass to the terminal
phalanx.

When pus collects under the dorsal expansion it cannot
spread on to the dorsum of the hand until it has infected the
metacarpo-phalangeal joint.

Radial Artery. — On leaving the forearm the radial artery
winds round the radial side of the wrist lying on the radial
collateral ligament. It crosses the dorsal surface of the navicular
and the os multangulum majus (trapezium), and then passes
forwards into the palm at the proximal end of the first inter-
osseous space to form the deep volar arch (Fig. 30).

The radial artery appears in the palm between the transverse
and the oblique heads of the adductor pollicis, and forms the
deep volar arch by joining the deep branch of the ulnar artery.
The arch lies deep to the flexor tendons and their synovial sheaths,
and, if haemorrhage from it cannot be controlled by pressure,
etc., recourse is usually had to ligature of the ulnar and radial
arteries. In this case the circulation is gradually re-established
through the volar and dorsal interosseous arteries (p. 71).

The deep arch, which lies one finger's-breadth proximal to
the superficial arch, sends branches proximally to join the volar
carpal arch, and distally to join the digital arteries.

Incisions on the Fingers. — Incisions on the palmar aspect

THE HAND 93

of the fingers are made in the middle line to avoid injuring the
digital vessels and nerves.

Incisions on the dorsal aspect of the first phalanx should be
confined, if possible, to the ulnar side to avoid injuring the
attachment of the lumbrical muscle (p. 84). In the case of
the second phalanx, dorsal incisions may be made to either side
of the extensor tendon. Septic infection on the dorsal surface
of the terminal phalanx is usually of the nature of an onychia
and involves the nail bed. It may spread to the bone unless
full exit is given to the pus by removal of the nail.

Ossification of the Metacarpals and Phalanges. — The
shafts and distal extremities of the phalanges ossify from primary
centres ; the proximal extremities from separate epiphyses,
which ossify during the third year and unite with the shafts at
twenty. The metacarpal bone of the thumb ossifies in the same
way as a phalanx, but in the other metacarpal bones the bases
and shafts are derived from the same primary centres, while
the heads are formed by separate epiphyses, ossifying at three
and uniting with the diaphyses at twenty.

Tuberculous Dactylitis usually attacks the centres of the
shafts of the metacarpals and phalanges instead of their ex-
tremities, probably because the nutrient artery on entering the
bone at once breaks up into small branches, whereas in the other
long bones it divides into large ascending and descending
branches. Owing to their mode of ossification, the diaphyses
of these bones cannot be completely resected subperiosteally
without opening one of the joints. On this account, after the
periosteum has been elevated, the bone is divided close to
the extremity which has no epiphysis. The diaphysis can
then be lifted and broken away from the epiphyseal cartilage
at the opposite extremity.

The Metacarpo-Phalangeal Joints possess volar and collateral
ligaments, but the dorsal ligament is replaced by the extensor
expansion. The volar accessory (glenoid) ligament is a plate
of fibrocartilage, which is firmly attached to the proximal
phalanx but only feebly connected with the metacarpal bone.

Dorsal Dislocation of the Thumb, at its metacarpo-
phalangeal joint (Hey's dislocation), is produced by extreme
dorsi-flexion of the thumb. The volar accessory ligament gives
way at its weak proximal attachment, and the phalanx passes
backwards, carrying the ligament with it. The distal phalanx
is flexed by the flexor pollicis longus. Hyper-extension at the

94 THE SUPERIOR EXTREMITY

metacarpo-phalangeal joint is primarily due to the causative

FJG. 33. — The Hand of a Child of three, showing Tuberculous Dactylitis.
The first metacarpal and the proximal phalanx of the index finger are
affected by the disease. Note the stage of ossification of the carpus and
metacarpus.

force, and is maintained by the abductor pollicis brevis, whose

THE HAND 95

" line of pull " falls behind the point of contact of the phalanx
with the head of the metacarpal. As soon as manipulations
have succeeded in bringing the line of pull in front of the point
of contact, hyper-extension is replaced by a slight degree of
flexion.

Difficulty in reduction may be caused (i) by the head of the
metacarpal being caught between the flexor pollicis brevis and
the adductor pollicis, (2) by the tendon of the flexor pollicis
longus slipping over to the ulnar side of the metacarpal, or (3)
by the interposition of the volar accessory ligament between the
two bones. Reduction is brought about by traction and hyper-
extension in order to allow the torn end of the volar ligament
to pass over the head of the metacarpal before the thumb is
flexed to the palm.

Development of Fingers. — During the sixth week of foetal life, four linear
furrows appear on the distal part of the upper limb. These deepen and
finally become clefts, which separate the digits from one another. The
furrows may be incomplete, giving rise to webbing of the ringers (syn-
dactylisni) ; or extra furrows may develop and produce supernumerary digits
(polydactylism). In the former case the furrow may be so shallow that the
bones of contiguous digits are fused together.

THE BRACHIAL PLEXUS AND ITS
BRANCHES.

The brachial plexus is formed by the anterior rami (anterior
primary divisions) of the lower four cervical and the first thoracic
nerves, assisted by small twigs from the fourth cervical and
the second thoracic nerves. The twig from the fourth cervical
joins the fifth, which then unites with the sixth, constituting the
Upper Trunk of the Plexus. The seventh cervical alone forms
the Middle Trunk. The eighth cervical and the first thoracic
unite to form the Lower Trunk. Each of these trunks divides
into an anterior and a posterior branch, and the three posterior
branches join to form the Posterior Cord of the Plexus. The
anterior branches of the upper and middle trunks join to form
the Lateral Cord, while the anterior branch of the lower trunk
forms the Medial Cord (Fig. 34).

96

THE SUPERIOR EXTREMITY

Supra- clavicular Branches.

Long Thoracic Nerve (of Bell), C. 5, 6, and 7.
Dorsalis Scapulae (Nerve to Rhomboids), C. 5.
Nerve to Subclavius, C. 5 and 6.
Supra-scapular, C. 5 and 6.

Infra- clavicular Branches.

( Lateral Anterior Thoracic (C. 5, 6, and 7).
Lateral Cord -! Lateral Head of Median (C. 5, 6, and 7).
{ Musculo-Cutaneous (C. 5, 6, and 7).

Scalenus anterior and longus colli
Scalenus medius and posterior

Phrenic nerve

Seal, anterior and longus colli

Seal, medius and posterior

Seal, anterior and longus colli
Seal, medius and posterior

Scalenus anterior and longus colli
Scalenus medius and posterior

FIG. 34. — Diagram of Brachial Plexus. (After Paterson.)

{Medial Anterior Thoracic (C. 8 and T. i).
Medial Cutaneous of Arm (Lesser Internal Cutaneous) (T. i).
Medial Cutaneous of Forearm (Internal Cutaneous) (C. 8
and T. i).
Medial Head of Median (C. 8 and T. i).
Ulnar (C. 8 and T. T).

Posterioi

THE BRACHIAL PLEXUS 97

f

(Upper (Short) Subscapular (C. 5 and 6).
Lower (Middle) Subscapular (C. 5 and 6).
Thoraco-dorsal (Long Subscapular) (C. 6, 7, and 8).
Radial (Musculo-Spiral) (C. 5, 6, 7, and 8).
Axillary (Circumflex) (C. 5 and 6).

Lesions of the plexus or of its constituent parts are followed
by alterations in the motor and sensory functions in the area
supplied. It must be remembered that the areas supplied by
cutaneous nerves overlap one another to a considerable extent,
and that section of a single cutaneous nerve will produce an area
of altered sensibility which is much smaller than the area of
anatomical supply of the nerve involved.

Note. — Three varieties of sensibility are described by Head and Sherren.
(i) Deep Sensibility. This form of sensation is conveyed by fibres which
run with the motor nerves and associate themselves with muscles, tendons,
periosteum, and ligaments. By these fibres coarse tactile stimuli are recog-
nised even after division of cutaneous nerves. Deep sensibility disappears
when a nerve is cut proximal to the origin of its motor branches, or when the
tendons, which convey the nerve fibres, are severed. (2) Protopathic
Sensibility. Painful cutaneous stimuli and extremes of temperature are
recognised by this form of sensibility, which is conveyed by the cutaneous
nerves. The areas of protopathic supply by different nerves overlap one
another to a considerable extent. (3) Epicritic Sensibility. This form
of sensation, which is also conveyed by the cutaneous nerves, responds to
light touch, localises accurately all painful and tactile stimuli, and recognises
intermediate degrees of temperature.

For a full and complete discussion of the various forms of sensation
the reader is referred to the works of the authors referred to above.

Lesions of the Supra-clavicular Branches.— The Long
Thoracic Nerve (of Bell) (C. 5, 6, and 7) and the Dorsalis
Scapulae Nerve (to the Rhomboids) (C. 5) both arise so close
to the inter vertebral foramina that they are rarely injured in
tears of the plexus. The latter nerve may be injured in removal
of lymph glands from behind the posterior belly of the omo-
hyoid,, unless the pervertebral fascia on the floor of the posterior
triangle of the neck is left intact (p. 135). In paralysis of the
rhomboid muscles the scapula on the injured side lies slightly
lower than it should; and the inferior angle is at a greater distance
from the median plane than it is on the sound side.

The Long Thoracic Nerve (of Bell) (p. 131) may be injured
in operations involving the axilla (p. 35) or by the pressure of
weights carried on the shoulder. In the latter case the dorsalis
scapulae nerve (to the rhomboids) and the branches of C. 3 and
C. 4 — both motor and sensory — which cross the posterior triangle
of the neck (p. 126), may also be injured. Owing to this com-

7

98 THE SUPERIOR EXTREMITY

plication, paralysis of the serratus anterior (s. magnus) is
frequently accompanied by paralysis of the lower part of the
trapezius and by pain, which radiates over the distribution of
C. 3 and C. 4. When the serratus anterior is paralysed alone,
the patient is unable to flex the humerus above the level of
the shoulder. If his arm is passively flexed above that level,
forward pushing movements cannot be performed, and attempts
to produce them cause marked winging of the scapula. All the
other movements, including forward pushing below the shoulder,
are intact, and, although the latter is weaker, it does not produce
winging of the scapula (Sherren). When in addition the lower
fibres of the trapezius (C. 3 and 4) are affected, no forward
pushing movement can be performed, and marked winging of
the scapula results on its being attempted.

The Supra-scapular Nerve (p. 127) arises from the upper
trunk of the plexus (C. 5 and 6) and supplies the supra- and
the infra-spinatus. When it is injured alone — a rare occurrence —
the resulting disability is slight, as lateral rotation of the humerus,
though definitely weakened, can still be performed by the
teres minor and the posterior fibres of the deltoid. In Erb-
Duchenne paralysis (p. 99) the lesion usually occurs proximal
to the origin of the supra-scapular nerve, which is therefore
involved.

Lesions of the Brachial Plexus. — As the brachial
plexus passes towards the axilla its constituent parts converge
on one another at the outer border of the first rib, the upper
having a downward and the lower an upward inclination. On
this account violence applied to the shoulder in a downward
direction will cause a stretching or tearing of the upper trunk
(Erb-Duchenne type, p. 99), and violence applied in the opposite
direction will affect the lower trunk in a similar manner (Klumpke
type, p. 100).

Supra-clavicular lesions of the plexus are generally brought
about as the result of trauma (e.g. in complicated labour, in
artificial respiration, when a person falling from a height grasps
something to save himself, or when the arm of an unconscious
patient hangs unsupported over the edge of an operating table),
but they may also occur from the pressure of a cervical rib.

Haemorrhagic extravasation or effusion into a nerve trunk is
quite sufficient to produce a temporary paralysis of the muscles
supplied. Rapid and complete recovery differentiates this
condition from an actual rupture of nerve fibres.

THE BRACHIAL PLEXUS 99

The whole plexus may be injured, but unless the nerves
are torn close to the intervertebral foramina, the rhomboids
and the serratus anterior escape. Sometimes all the trunks
of the plexus are torn, and when this occurs distal to the origin
of the supra-scapular nerve, the supra- and the infra-spinatus
escape paralysis. The examination of these muscles and of the
condition of the pupil (pp. 98, 125) helps to determine the site
of all such extensive lesions.

In these injuries, epicritic and protopathic sensibility are lost
over the whole arm, except in the areas supplied by the descend-
ing branches of the cervical plexus (C. 3 and 4) on the lateral side
of the arm, and by the intercosto-brachial nerve on the medial
side of the arm (Fig. 13). The full area of supply of these
nerves is demonstrated as the overlapping nerves are all
paralysed.

It is important to remember that limited haemorrhage into
the spinal medulla, from disease or accident, or the onset of
acute anterior poliomyelitis may give rise to clinical signs similar
to those produced by injuries of the plexus. It is necessary,
therefore, to examine the lower limbs for signs of motor and
sensory disturbance in order to determine whether the plexus
or the spinal medulla is the site of the lesion.

Erb-Duchenne or Upper Arm Type of Paralysis. — This
condition results usually from downward traction of the shoulder
during complicated labour. The upper trunk is torn proximal
to the origin of the supra-scapular nerve, but distal to the origins
of the long thoracic nerve (of Bell) and the dorsalis scapulce nerve
(to the rhomboids). The serratus anterior and the rhomboids
consequently escape, but all the other muscles innervated by
C. 5 and C. 6 are paralysed (p. 106). The deltoid, teres minor,
and infra-spinatus are all affected, and the arm is rotated medially
by the latissimus dorsi (C. 6, 7, and 8) and the sternal head of the
pectoralis major, the latter owing to its supply from the medial
anterior thoracic nerve (C. 8 and T. i). The biceps and the
brachio-radialis are paralysed and the brachialis (C. 5, 6, and 7)
is greatly weakened. The elbow is generally extended owing
to the action of the triceps (C. 7 and 8), which usually escapes.
The supinators are all paralysed and the forearm is pronated
by the pronator quadratus (C. 7, 8, and T. i) alone, the pronator
teres being supplied by C. 6. The radial extensors of the wrist
being affected, the hand is deviated to the ulnar side, but all the
other movements of the wrist and fingers are unchanged.

7a

ioo THE SUPERIOR EXTREMITY

As the arm is fully pronated, the extensor digitorum com-
munis and carpi ulnaris (C. 6, 7, and 8) may subsequently be
able to produce a small degree of flexion at the elbow.

When the lesion is confined to the anterior ramus (primary
division) of C. 5, no sensory changes can be discovered; as it is
not responsible for the exclusive supply of any definite area of
skin. If C. 6 also is involved, there is usually some loss of
epicritic sensibility on the lateral aspects of the arm and forearm.

In the treatment of this and other similar conditions, it must
be remembered that unless the paralysed muscles are relaxed
they will become overstretched by the unopposed action of the
unparalysed antagonistic muscles.

Surgical approach to the plexus is described on p. 127.

Klumpke's Paralysis : Lower Arm Type. — This condition
results from upward traction on the shoulder, e.g. when a man
falling from a height seizes something to save himself, or in a
breech presentation when the arms are carried up above the
head. The lesion usually affects the first thoracic nerve, but it
may involve the whole of the lower trunk (C. 8 and T. i). The
intrinsic muscles of the hand are paralysed and a characteristic
claw-hand develops. (The fingers are hyper-extended at the
metacarpo-phalangeal joints and flexed at the inter-phalangeal
joints.) If the whole of the lower trunk is affected the flexors
and extensors of the fingers are paralysed in addition (Sherren).

Diminution of sensibility occurs over the medial side of the
arm, forearm, and hand, the area of protopathic loss being
greater than the area of epicritic loss. When the first thoracic
nerve is injured proximal to the point at which it sends off the
white ramus communicans to the first thoracic ganglion of the
sympathetic, the cilio-spinal reflex (p. 125) is abolished.

A Cervical Rib (p. 128) may produce a supra-clavicular
lesion of the brachial plexus. In these cases the symptoms
appear usually on the right side and indicate involvement of
the lower trunk. No pupillary changes are present, as T. i
is affected beyond the origin of its white ramus communicans.
Neuralgic pain radiates down the ulnar side of the upper limb
in the areas supplied by the nerves involved (Fig. 14), and
there may be some epicritic loss in the same situation. Wasting
and progressive paresis occur in the intrinsic muscles of the
hand. Recent observations have shown that the same symptoms
may be produced by the pressure of the first rib.

Injuries to the Cords of the Plexus.— The Medial

THE BRACHIAL PLEXUS 101

Cord may be torn or stretched in subcoracoid dislocation of
the humerus or by the " heel in axilla " method of reduction.
Sensory changes are found in the areas supplied by the ulnar,
and the medial cutaneous nerves of the arm and forearm (Fig.
12). All the muscles supplied by the medial cord are paralysed,
i.e. the intrinsic muscles of the hand, supplied by the ulnar and
medial head of the median, and the flexor carpi ulnaris and the
ulnar part of the flexor digitorum profundus, both supplied by
the ulnar nerve.

The Lateral Cord may be injured in the same way. All
the muscles supplied by the musculo-cutaneous nerve (biceps,
coraco-brachialis, and brachialis, partly) and by the lateral head
of the median (superficial and deep muscles of front of forearm)
(p. 72) are paralysed. Partial epicritic insensibility exists in
the areas supplied by the musculo-cutaneous and median nerves
(Fig. 12).

Injury of the Posterior Cord produces all the signs of
combined radial (musculo-spiral) and axillary (circumflex)
paralyses.

Lesions of the Infra-clavicular Branches of the
Plexus. Axillary (Circumflex) Nerve. — When this nerve is
paralysed (p. 39) the deltoid atrophies and the bony land-
marks become prominent — a condition which must be differ-
entiated from wasting of the muscle following disease of the
shoulder-joint. Lateral rotation is not greatly affected by the
paralysis of the teres minor, but abduction can only be produced
by the supra-spinatus. A marked loss of epicritic and proto-
pathic sensibilities over the distal part of the deltoid always
accompanies injury to the axillary (circumflex) nerve.

The Radial (Musculo-Spiral) Nerve may be pressed on in
the axilla, e.g. " crutch " and " Saturday-night " paralysis.
It is damaged in 8 per cent of fractures of the distal two-
thirds of the shaft of the humerus, either at the time of the
accident or in the subsequent formation of callus, and it has
occasionally been injured in wiring ununited fractures of the
humerus.

The Dorsal Interosseous Nerve is sometimes injured in
fractures of the neck of the radius and in dislocations of that
bone. It may be cut in operations which involve incisions
into the supinator (s. brevis) (p. 65). The Superficial Branch
of the Radial Nerve (Radial Branch of Musculo-Spiral) may be
injured in wounds about the lateral and dorsal aspects of the

7b

102 THE SUPERIOR EXTREMITY

wrist, but if no other nerves are involved, no sensory change is
apparent (vide infra).

Injury to the Radial (Musculo-Spiral) nerve occurs most
commonly in its distal third beyond the origin of its cutaneous
branches and of the nerve-supply of the triceps and the anconseus.
All the remaining muscles supplied directly by the radial
(musculo-spiral) nerve (p. 73) and indirectly by its deep branch
(posterior interosseous nerve) are paralysed, and the characteristic
deformity of " Drop Wrist " develops. The patient is unable
to extend his wrist or fingers, but, if the first phalanges are
supported when he attempts to do so, the lumbricals and interossei,
which act in harmony with the extensor apparatus, will extend
the fingers at the inter -phalangeal joints (p. 84).

No sensory changes accompany injury to the radial (musculo-
spiral) nerve in its distal third. Its superficial branch (radial
nerve) is paralysed, but on account of the communications
which it establishes with other nerves, no change of sensibility
can be determined.

Note. — The dorsal branch of the lateral cutaneous (from the musculo-
cutaneous nerve), the superficial (radial) branch of the radial (musculo-
spiral) nerve, and the dorsal cutaneous nerve of the forearm (lower external
cutaneous branch of the musculo-spiral) communicate with one another
and overlap to such an extent that no sensory symptoms are produced by
section oj any one of the nerves by itself. If any two are injured there is some
loss of epicritic and protopathic sensibility, extending from the bases of the
lateral three digits to the dorsum of the wrist, but complete epicritic and
protopathic loss in this area occurs only after division of all three (Sherren).

When the dorsal interosseous nerve is injured, the motor
symptoms are the same as those described above, except that
the brachio-radialis and extensor carpi radialis longus escape.
As a result, the patient is able to extend the wrist, but the
movement is weak.

The " Drop Wrist " of lead poisoning can be differentiated
from both the above varieties, as the brachio-radialis is not
affected while the extensor carpi radialis longus is paralysed.

Musculo-Cutaneous Nerve. — The main trunk of this nerve
is rarely injured by itself, but the cutaneous portion or one of
its branches may be cut in incisions and wounds of the forearm.

In injury of the main trunk, the biceps and the coraco-
brachialis are paralysed and the brachialis is weakened (p. 41).
Flexion of the forearm is still possible, and is performed by the
krachialis and the superficial flexors of the forearm when the
hand is supine, but, when the forearm is in the prone or mid-

THE BRACHIAL PLEXUS 103

prone position, the brachio-radialis and the extensor carpi
radialis longus assist in its production.

Epicritic and protopathic insensibility occurs over the
radial half of the forearm. In front, the boundary line is very
constant and runs from the line of the ring finger at the wrist
to the tendon of the biceps. Dorsally the boundary line is not
so definite and the insensitive area varies inversely with the
size of the dorsal cutaneous nerve of the forearm (lower external
cutaneous branch of the musculo-spiral nerve).

Section of the cutaneous portion of the musculo-cutaneous
nerve produces the same sensory symptoms as those which
result from injury of the main trunk. Section of its volar or
of its dorsal branch produces no change in sensibility owing to
the overlapping by adjoining nerves.

Medial Cutaneous Nerve of the Forearm (Internal
Cutaneous Nerve). — When the main trunk of this nerve is cut,
epicritic and protopathic sensibility are lost over the ulnar side
of the forearm, but if one of the terminal branches is injured,
epicritic sensibility alone is lost over the area involved.

Ulnar Nerve. — The ulnar nerve is liable to injury at the
wrist, where it is exposed to cuts and stabs, and at the elbow,
where it may be involved in fractures, dislocations, or operations
on the joint.

i. At the Wrist. — The injury may occur either proximal or
distal to the origin of the dorsal cutaneous branch, and, though
the motor symptoms are exactly similar, the sensory changes
are slightly different in the two cases.

All the intrinsic muscles of the hand, save those supplied
by the median nerve (p. 86), are paralysed, and a characteristic
deformity (partial main en griff e) is produced. In cases seen
immediately after the accident, the injury to the nerve may be
overlooked when no tendons are cut, as the patient appears, on
superficial examination, to be able to perform most of the
movements of the fingers. It is always essential in these cases
to ask the patient to separate the fingers, and, if he is unable to
do so, paralysis of the dorsal interossei and of the abductor
digiti quinti is at once discovered and a more thorough examina-
tion should then be made.

In old-standing cases, the paralysed muscles atrophy and
the fingers are extended at the metacarpo-phalangeal joints, as
the balance between the flexors and extensors is lost, owing
to paralysis of the interossei. In the little and ring fingers the

io4 THE SUPERIOR EXTREMITY

balance is further upset by paralysis of the lumbrical muscles
(p. 84), and as the action of these muscles on the dorsal extensor
expansion (p. 92) is lost, hyper- extension at the metacarpo-
phalangeal joints and flexion at the inter-phalangeal joints
result. The thumb is abducted owing to paralysis of the
adductor, and consequently the grasping power of the hand is
greatly diminished.

When the ulnar nerve is cut distal to the origin of its dorsal
cutaneous branch, epicritic sensibility is lost over the ulnar side
of the palm, the palmar aspects of the little ringer and ulnar side
of the ring ringer, and the dorsal aspects of the second and third
phalanges of the same fingers. Protopathic loss varies, and
deep sensibility is always present in these cases unless many
tendons are cut. When the injury occurs proximal to the origin
of the dorsal cutaneous branch, all the previous sensory symptoms
are present, and, in addition, epicritic sensibility is lost over the
ulnar side of the dorsum of the hand and over the dorsal aspects
of the proximal phalanges of the little finger and ulnar side of
the ring finger.

2. At the Elbow. — In injury of the ulnar nerve at this site,
the additional muscular paralysis produces a slight change in
the deformity of the hand. The portion of the flexor digitorum
profundus destined for the ring and little fingers is paralysed,
and therefore the terminal phalanges of these fingers are not
flexed, as in (i), but are hyper-extended by the unopposed
action of the extensor expansion. Radial deviation of the
hand occurs on flexion of the wrist owing to paralysis of the
flexor carpi ulnaris.

The sensory changes are exactly similar to those which occur
in section of the nerve at the wrist above the origin of the dorsal
cutaneous branch. In addition, there is some loss of deep
sensibility on the ulnar side of the palm.

Median Nerve. — The median nerve is most commonly injured
as it lies between the tendons of the palmaris longus and the
flexor carpi radialis at the proximal border of the transverse
carpal ligament (p. 67). It is here cut by stab-wounds, the
neighbouring tendons usually escaping injury.

Motor Symptoms. — The abductor and the flexor pollicis
brevis, the opponens pollicis, and the first and second lumbricals
are the only muscles affected. The thumb cannot be abducted
(p. 84), but the movement of opposition may be imitated by
the flexor pollicis longus. When the patient is told to close the

THE BRACHIAL PLEXUS 105

hand slowly, the index and middle fingers lag behind the other
two, as the balance between the extensors and flexors is disturbed
by the lumbrical paralysis (see Ulnar Nerve, p. 103). Hyper-
extension of the index and middle fingers at the metacarpo-
phalangeal joints and adduction of the thumb are the
characteristic features of the condition when the hand is at rest.

Sensory Symptoms. — Epicritic sensibility is lost over the
palm of the hand and over the area supplied by the digital
branches. On the dorsal aspect, epicritic sensibility is lost over
the second and third phalanges of the same fingers, but there is
no sensory change on the dorsum of the thumb. The radial
side of the thenar eminence is not affected. If many tendons
are cut, as well as the nerve, deep sensibility is interfered with,
and there is additional muscular paralysis.

When the median nerve is injured proximal to the bend of
the elbow, the sensory symptoms are the same as those described
above, but, in addition, deep sensibility is diminished over the
palmar aspect of the hand and fingers. The amount of muscular
paralysis is greatly increased, as the nerve is injured proximal
to the origin of the branches supplying the muscles on the front
of the forearm (p. 72). True pronation is lost, but the brachio-
radialis carries the forearm from the supine into the mid-prone
position and then, if the arm is abducted, the weight of the
hand can complete the action. Flexion of the wrist with ulnar
deviation is performed by the flexor carpi ulnaris and the ulnar
half of the flexor digitorum profundus. The thumb is still
adducted, but the terminal phalanx is kept extended owing to
paralysis of the flexor pollicis longus. The index and middle
fingers are practically useless, as no flexion is possible at the
inter-phalangeal joints, and the interossei — which are the only
flexor muscles unaffected — are but feeble flexors of the metacarpo-
phalangeal joints when they have to initiate the movement.
On the other hand, the ring and' little fingers are weakened only
by the loss of the flexor digitorum sublimis tendons.

Segmental Inner vation of the Muscles of the Superior
Extremity. — The statements made in the foregoing pages
regarding the segmental innervation of the individual muscles
are substantially in agreement with the descriptions given in
modern anatomical text-books, but they differ, in many instances,
from the descriptions given by Kocher, whose views are based
on clinical data. His conclusions are embodied in the following
table :

io6

THE SUPERIOR EXTREMITY

Nerve.

Muscles.

C. V.

C. VI.

C. VII.
C. VIII.
T. I.

Rhomboids, supra- and infra-spinatus, deltoid, teres
minor, coraco-brachialis, biceps, brachialis, brachio-
radialis, and supinator. (Abductors and lateral
rotators of the shoulder ; flexors and supinators of
forearm.)

Pectoralis major and minor, subscapularis, latissimus
dorsi, teres major, serratus anterior, triceps, pronator
teres, and pronator quadratus. (Adductors and
medial rotators of shoulder ; extensors and pronators
of forearm.)

Extensors and flexors of the wrist.
Long flexors and extensors of the fingers.
Small muscles of the hand.

THE NECK 107

THE HEAD AND NECK.

THE NECK.

Surface Landmarks. — The sterno-mastoid muscle, which is
the most important landmark in the neck, forms an elevation,
i£ inches wide, between the anterior and posterior triangles.
If its anterior border is traced upwards, the mastoid process
can be felt lying under cover of the lobule of the ear, rather more
than one inch above and behind the angle of the mandible.
On deep pressure, midway between these two bony points,
pain is elicited owing to the compression of the skin and parotid
gland against the subjacent transverse process of the atlas vertebra.

In the anterior median line of the neck the laryngeal promin-
ence, due to the forward projection of the thyreoid cartilage,
forms a conspicuous landmark, which is more prominent in
men than in women. The greater cornu of the hyoid bone is situ-
ated midway between the mastoid process and the laryngeal
prominence, but, owing to its mobility, it cannot be made out
unless the bone is steadied by placing a finger at the same level
on the opposite side of the neck. When the greater cornu is
traced forwards, the body of the hyoid bone can be examined.
It lies about an inch above the laryngeal prominence and on
a level with the lower part of the third cervical vertebra. The
arch of the cricoid cartilage, which lies i| inches below the
laryngeal prominence, is placed opposite the sixth cervical
vertebra. If the finger is thrust backwards and laterally under
cover of the anterior border of the sterno-mastoid at this
level, the common carotid artery may be compressed against
the anterior tubercle of the transverse process of the sixth
cervical vertebra — the carotid tubercle.

The anterior border of the trapezius may be traced from its
origin on the occipital bone downwards, round the side of the
neck, to its insertion into the clavicle.

The spine of the seventh cervical vertebra can be identified as it
lies at the lower end of the nuchal furrow ; the upper six cervical

io8 THE HEAD AND NECK

spines lie at the bottom of the nuchal furrow, and are obscured
by the ligamentum nuchae.

The Platysma. — This muscular sheet lies in the superficial
fascia of the neck. Its anterior border runs obliquely upwards
and medially. For a short distance below the chin it meets
and decussates with the corresponding muscle of the opposite
side, but the two muscles separate from one another below
(Fig. 51). It is supplied on its deep surface by the cervical
branch of the facial nerve. The platysma aids the facial muscles
which drag downwards the lower lip and the angle of the mouth.
Incisions which approach too near to the angle of the mandible
(p. 134) may cut the nerve to the platysma (and depressor labii
inf.) and cause paralysis of the movements indicated.

Superficial Nerves. — The skin of the front and side of the
neck is supplied by branches from C. 2, C. 3, and C. 4. The
nerves appear from under cover of the sterno-mastoid, near
the middle of its posterior border, and radiate in various direc-
tions. Like the superficial veins, they lie deep to the platysma.

The descending, supra-clavicular, branches (C. 3 and C. 4)
are described on p. 4.

The ascending branches are the lesser occipital (C. 2), which
runs upwards along the posterior border of the sterno-mastoid
to the scalp, and the great auricular (C. 2 and 3), which ascends
across the muscle superficially, and supplies the skin over the
angle of the jaw and the postero-inferior part of the auricle.
The great auricular nerve usually accompanies the upper half
of the external jugular vein (Fig. 35).

These nerves are commonly divided in operations for the
removal of tuberculous lymph glands, and occasionally their
cut ends become adherent to the scar. Neuralgia, arising
from this cause, radiates over the area supplied by the other
nerves which arise from the same segment of the spinal medulla
as the nerve involved. The surgeon may resect the superficial
nerves of the neck as soon as they are exposed as a prophylactic
measure, and, although some loss of sensation may result, the
condition gradually improves.

Posteriorly, the skin is supplied by the posterior rami (primary
divisions) of the second to the sixth cervical nerves.

The line of anaesthesia in fracture dislocations below the
fourth cervical vertebra is described on p. 530.

The External Jugular Vein is formed at the lower border of
the parotid gland by the union of the posterior auricular and a

THE NECK

109

branch (the posterior division of the temporo-maxillary) from
the posterior facial vein (Fig. 35). It is visible as it descends
vertically across the sterno-mastoid to the angle between its
posterior border and the clavicle, where it enters the subclavian

Auriculo-temporal
nerve

Cervical brand
of facial nerve
Nervus cutaneus coll

External jugiil

Greater occipital nerve
Posterior auricular vein

Third occipital nerve

imencement of external jugular vein
Lesser occipital nerve
Great auricular nerve
Nerve to levator scapula;
Accessory nerve

Branches to trapezius from C. 3 and 4
Supra-clavicular nerves

sverse cervical vein

Oino-hyoid, post, belly
Transverse scapular vein

Connecting branch

Cephalic veil

FIG. 35. — Superficial Nerves and Veins of the Neck.

vein after piercing the deep fascia. About its mid-point the
external jugular vein receives a tributary, which drains the
superficial tissues of the posterior aspects of the scalp and th^
neck. After piercing the deep fascia, it is joined on its lateral
side by the transverse cervical and transverse scapular (supra-
scapular) veins, and, on its medial side, by the anterior jugular.

no THE HEAD AND NECK

The vein wall is very adherent to the margins of the opening
in the deep fascia through which it passes, and at this point,
therefore,, the vein cannot collapse. If the vessel is cut in this
region there is danger lest air be drawn in by the suction of the
chest in inspiration, and on this account the finger should
immediately be applied over such a wound. In its upper half
the external jugular vein is commonly accompanied by the great
auricular nerve, and throughout its whole course it is closely
related to the superficial cervical lymph glands.

Owing to its superficial position, the external jugular vein
may be opened to relieve the venous congestion which sometimes
occurs during the administration of an anaesthetic from disten-
tion of the right side of the heart.

The Anterior Jugular Vein arises just below the chin and
runs downwards near the anterior median line of the neck (p. 164).
It turns laterally deep to the sterno-mastoid, just above the
clavicle, and joins the external jugular vein close to its termina-
tion. Occasionally the anterior jugular is joined by the common
facial vein. The two anterior jugular veins are connected by a
transverse branch (Fig. 51) which lies in the suprasternal space
(of Burns) (p. in).

The superficial veins of the neck vary considerably in size,
and the increase of one is balanced by the decrease of another.

The Superficial Cervical Lymph Glands lie in the superficial
fascia of the neck. They consist of three groups, (A) Occipital,
(B) Mastoid, and (C) a chain of glands accompanying the external
jugular vein.

A. The Occipital lymph glands lie at the apex of the posterior
triangle. They receive afferents from the posterior part of the
scalp, and are commonly enlarged in pediculosis or impetigo
of the area which they drain. Their efferents pass partly to
group (C), and partly to the upper posterior group of the deep
cervical lymph glands (p. 132).

B. The Mastoid lymph glands lie on the upper part of the
sterno-mastoid. They drain the adjoining area of the scalp
and the deep surface of the pinna, and their efferents take the
same course as the efferents of the occipital glands.

C. This group receives afferents from the Occipital and
Mastoid lymph glands, which are the usual sources of infection.
They are not liable to tuberculous disease, and therefore, when
they become enlarged, there is very little periadenitis, so that
they can easily be felt to slip about beneath the platysma.

THE NECK in

Deep Cervical Fascia. — The deep fascia of the neck con-
sists of an investing layer and of several subsidiary processes.

(a) The Investing Layer forms the roof of the anterior
triangle, and is firmly bound down to the hyoid bone. Traced
laterally, it encloses the sterno-mastoid, forms the roof of the
posterior triangle, and then invests the trapezius (Fig. 36). It
is attached above to the lower border of the mandible, but, in
the neighbourhood of the angle, it is carried upwards, enclosing
the parotid gland, to the zygomatic arch and the antero-inferior
border of the external acoustic (auditory) meatus. It is attached
to the mastoid process, the superior nuchal line of the occipital
bone, and the external occipital protuberance, i.e. it corresponds
to the attachments of the sterno-mastoid and the trapezius.

Between the angle of the mandible and the greater cornu
of the hyoid bone, the investing layer blends with the fascial
sheath of the posterior belly of the digastric ; between the chin
and the greater cornu a similar connection is formed with the
fascial sheath of the anterior belly of the digastric. In this
way the submaxillary and submental regions are shut off from
one another and from the rest of the neck (p. 145).

Just above the jugular (suprasternal) notch the investing
layer splits into two lamellae, which are attached to the front
and back of the manubrium sterni. The space between them —
the suprasternal space (of Burns} — contains one or two lymph
glands and a communication between the two anterior jugular
veins (Fig. 51). Traced laterally, these two layers enclose the
sterno-mastoid, and pass down to the clavicle. In the lower
part of the posterior triangle the same two layers can again be
recognised, and, for about an inch above the clavicle, they are
separated by some loose fat. The deeper layer encloses the
posterior belly of the omo-hyoid, and holds it down in place ; the
superficial layer, which is very thin and ill-defined, is continuous
with the fascia covering the trapezius.

The investing layer is much stronger over the triangles than
it is over the trapezius and the sterno-mastoid. So firmly does
it bind the structures together that, in operations on the neck,
good exposure can be obtained only after it has been divided
freely. In flap operations the flap should consist of all the tissues
down to and including the deep cervical fascia.

(b) The Prevertebral Fascia covers the muscles which are
closely applied to the anterior aspects of the cervical vertebrae.
It is attached above to the basi-occiput, and it passes down as

112

THE HEAD AND NECK

a thick sheet into the thorax, where it blends with the anterior
longitudinal (common) ligament. Traced laterally, the pre-
vertebral fascia gradually becomes thinner. It passes behind
the great vessels of the neck and covers the muscles on which
they lie, viz. the longus colli, the longus capitis (rectus capitis
anticus major), and the scalenus anterior. It is then continued
on to the surfaces of the adjacent muscles, viz. the splenius

Sterno-hyoid Anterior jugular vein, transverse anastomosis
Anterior jugular vein | | Trachea

Recurrent nerve I Suprasternal space

Parathyreoid gland I i Sheath of thyreoid gland

Investing layer | | | | | (Ksophagus

Sterno-thyreoid v^A-rt3^4-=^ — i^^Zr-/-^ Thyreoid gland

Sheath of thyreoid gland >^^<SJfiSlE3E83s2RSifc5*^, Capsule of thyreoid gland
Sterno-mastoid >^2«Sgi ^g^l^v C!t7ugU[ar «?*"*

arotid sheath

t-ertebral fascia

xt. jugular vein
Onio-hyoid

Investing

layer of deep

cervical

fascia

Sympathetic trunk '
Inferior thyreoid artery

-ong- thoracic nerve (of Bel
Vertebral vessels

FIG. 36. — Transverse Section through Neck, at level of Seventh Cervical
Vertebra, showing the arrangement of the Deep Cervical Fascia. On
the left side, a tuberculous abscess is shown, originating in the body of
a vertebra and spreading laterally behind the pre vertebral fascia. After
eroding the muscles, it has penetrated the prevertebral fascia and made
its way into the posterior triangle of the neck.

capitis, the levator scapulae, the scalenus medius and posterior,
i.e. it forms the fascial floor of the posterior triangle. As the
anterior rami (primary divisions) of the cervical nerves lie on
the upper surfaces of the transverse processes of the vertebrae,
they are situated behind the prevertebral fascia. The superficial
branches of the cervical plexus soon pierce it, but the phrenic
nerve lies deep to the fascia as it runs down in front of the scalenus
anterior. When the roots of the brachial plexus and the sub-
clavian artery emerge from under cover of the scalenus anterior,
they carry the prevertebral fascia with them downwards and

THE NECK 113

laterally towards the apex of the axilla, and so form the axillary
sheath. It will be seen from Fig. 36 that the prevertebral
fascia, after covering the floor of the posterior triangle, blends
with the fascia on the deep surface of the trapezius and reaches
the ligamentum nuchse. In this way it forms a complete layer

Genio-hyoid

Sublingual gland

-Genio-glossus
jJ^S

3\ fT-xV Mylo-hyoid

Epiglottis

Investing layer

Lingual artery
Submaxillary gland
Hyo-glossus
Palatine tonsil

Greater cornu of
hyoid bone

Sterno-mastoid

Carotid sheath

Bucco- pharyngeal
fascia

Sympathetic trunk

Retro-pharyngeal
lymph gland

SSM*J«. ^fSf^^ Vertebral vesse,s

Retro-pharyngeal
abscess

Prevertebral fascia Trapezius

FIG. 37. — Transverse Section through the Neck of a Child, at the level of the
Third Cervical Vertebra, showing the arrangement of the Deep Cervical
and Bucco-pharyngeal fasciae. An abscess is shown in the retro-
pharyngeal space, originating in one of the lymph glands in that situation.
Its relation to the prevertebral fascia should be carefully noted. Cf.
Fig. 50.

around the neck, but it lies on a deeper plane than the investing
layer.

Pus arising from tuberculous disease of the upper cervical
vertebrae lies behind the prevertebral fascia (Fig. 36). It forms
a swelling on the posterior wall of the pharynx which causes
difficulty in swallowing and respiration. Owing to the strength

8

ii4 THE HEAD AND NECK

of the fascia in the median plane, the pus travels downwards
and laterally behind the carotid sheath and reaches the posterior
triangle. In this situation the fascia is much weaker, and the
abscess points behind the sterno-mastoid. It is best approached
by an incision along the posterior border of the muscle (Chiene),
which is then retracted forwards together with the carotid sheath.
A search is made for the transverse processes of the cervical
vertebrae,, which provide the deep landmarks to the site of the
abscess (p. 520). Rarely, the pus travels downwards behind
the prevertebral fascia and enters the mediastinal space. This
variety of abscess must be distinguished from an abscess originat-
ing in the lymph glands which occupy the interval between
the prevertebral fascia and the bucco-pharyngeal fascia on the
outer surface of the constrictor muscles (Fig. 37). They drain
the naso-pharynx, and their efferents pass laterally to open
into the upper group of the deep cervical lymph glands. An
abscess arising in connection with the retro -pharyngeal lymph
glands causes a swelling on the posterior wall of the pharynx,
usually to one or other side of the median plane. Should it
rupture into the pharynx during sleep, it may lead to suffocation.
Abscesses in front of the prevertebral fascia should be opened
from the mouth with the patient's head inverted (Rose's posi-
tion), but this route is avoided in dealing with pus behind the
prevertebral fascia — which is tuberculous in origin — on account
of the danger of mixed infection.

(c) The Pretracheal Fascia is a much thinner sheet than
the prevertebral. It lies in front of the trachea and the lower
part of the larynx, and forms a fascial sheath for the thyreoid
gland (p. 167). It is separated from the prevertebral fascia
by the oesophagus and trachea, and from the investing layer by
the depressor muscles of the hyoid bone (Fig. 36). The pre-
tracheal fascia covers the crico-thyreoid muscle and is firmly
adherent to the cricoid and thyreoid cartilages. It does not
extend upwards beyond the thyreoid cartilage but, inferiorly,
it descends into the superior mediastinum and blends with the
outer coat of the arch of the aorta. Laterally, the pretracheal
fascia blends with the anterior wall of the carotid sheath.

(d) The Carotid Sheath. — The common and internal carotid
arteries, the internal jugular vein, and the vagus nerve, are
surrounded by a tubular investment of the deep cervical fascia.
The sheath is best seen in relationship to the upper half of the
common carotid artery : above and below that area it gradually

THE NECK 115

becomes indefinite. The posterior wall of the sheath is con-
nected to the prevertebral fascia by some loose connective tissue,
which, however, does not prevent pus from spreading laterally
between them ; its anterior wall fuses with the pretracheal
fascia.

Relations of the Carotid Sheath. — The carotid sheath is so
frequently exposed in operations on the neck that its relations
require careful consideration. At its lower end it is covered
by the sterno-hyoid and the sterno-thyreoid muscles and, more
superficially, by the sternal head of the sterno-mastoid. Between
these two muscular layers the anterior jugular vein runs laterally,
just above the clavicle, and hence it runs the risk of injury when
these muscles are separated. Opposite the cricoid cartilage,
the sheath is crossed obliquely by the anterior belly of the
omo-hyoid (Fig. 38). (The intermediate tendon of the muscle
exactly overlies the internal jugular vein.) Above that level,
the carotid sheath is overlapped by the anterior border of the
sterno-mastoid, but, just below the mandible, it appears partially
from under cover of the muscle. Above the level of the hyoid
bone the great vessels pass deep to the stylo-hyoid and the
posterior belly of the digastric. Numerous tributaries of the
internal jugular vein (p. 118) cross the medial part of the sheath
to reach their destination. Opposite the hyoid bone the sheath
is crossed transversely by the hypoglossal nerve (p. 124) and,
at the upper border of the omo-hyoid, by the branch from the
superior thyreoid artery to the sterno-mastoid.

Posteriorly, the sheath rests on the longus colli in its lower
part, and it forms the roof of the deep triangle of the neck (p. 138).
Superiorly, it lies on the transverse processes of the cervical
vertebrse and on the muscles which arise from them, viz. the
scalenus anterior and the longus capitis (rectus cap. antic, major).
The sheath extends laterally so as to overlap the phrenic nerve
as it lies on the scalenus anterior.

On its medial side the carotid sheath is closely applied to the
trachea, the oesophagus, and the recurrent (laryngeal) nerve ;
the posterior border of the lateral lobe of the thyreoid gland is
an intimate relation and may overlap the sheath, while, at a
higher level, the inferior and middle constrictors of the pharynx
and the thyreo-hyoid membrane lie to its medial side.

Laterally, the sheath is related to the deep surface of the
sterno-mastoid, save where the depressors of the hyoid bone
intervene.

Sa

n6 THE HEAD AND NECK

Within the carotid sheath lie the common carotid and the
commencement of the internal carotid artery, the internal jugular
vein, the vagus nerve, and some lymph glands. The artery
is situated medially and on a plane somewhat anterior to the
internal jugular vein, but it is overlapped by the vein, which is
considerably the larger of the two vessels. The vagus nerve
lies between and behind the artery and the vein. The ramus
descendens hypoglossi (p. 154) is embedded in the anterior aspect
of the sheath.

(e) The Stylo-mandibular Ligament connects the styloid
process to the deep surface of the angle of the mandible. It
forms a part of the sheath of the parotid gland, and it separates
the parotid from the submaxillary region.

The Sterno-mastoid Muscle arises by a sternal and a
clavicular head, separated from one another by a triangular
interval, in the floor of which lies the lower end of the carotid
sheath. The fibres of the muscle pass upwards and backwards
to the mastoid process and the superior nuchal line of the
occipital bone. The muscle is firmly held in place by the deep
fascia, and its anterior border shows a forward convexity
which disappears when the fascia is incised along it, permitting
the carotid sheath to come into view. The nerve-supply of the
sterno-mastoid is derived from the accessory (spinal accessory)
nerve and the anterior ramus (primary division) of C. 2. When
the accessory nerve is cut, the muscle of the opposite side, being
unopposed, draws the head down to its own side, and at the same
time rotates and tilts the head so that the chin is directed up-
wards and towards the affected side. In these cases, therefore,
the torti-collis is found on the other side of the neck from the
causative lesion. Congenital torti-collis is due to shortening of
the muscle of the same side, either from mal-development or
from cicatricial fibrosis following rupture during parturition.

Acquired torti-collis may be due to astigmatism, or to the
irritation of the second cervical nerve by Potts' disease, or it may
be caused by the pressure of inflamed lymph glands on the
accessory nerve. This variety can always be distinguished from
the true form by the absence of facial asymmetry.

In the treatment of congenital torti-collis, subcutaneous
tenotomy of the sterno-mastoid near its origin has fallen into
disuse on account of the danger of wounding the anterior or the
external jugular vein (p. 108). In addition, the deep cervical
fascia, which is also contracted, must be divided in order to

THE NECK 117

ensure a successful result, and this proceeding cannot be carried
out by the subcutaneous method. At the present time an open
operation is performed through an oblique incision across the
lower part of the muscle. The deep fascia is freely incised, and
the muscle is divided along with the fascia on its deep surface.
It may even be necessary to open the carotid sheath to obtain
sufficient relaxation.

The Internal Jugular Vein is a direct downward con-
tinuation of the transverse (lateral) sinus, and it emerges from the
skull at the posterior part of the jugular foramen. In its upper-
most part it is rarely seen by the surgeon, since it lies deeply,
under cover of the styloid process and the parotid gland. It
descends in the carotid sheath, the relations of which are
described on p. 115, and it is covered by the sterno-mastoid
muscle. In the sheath the vein lies on the lateral side of the
common carotid artery and its terminal branches, but it overlaps
them anteriorly. When an opening is made in the carotid
sheath, the vein bulges through and it is easily recognised by
its blue-grey colour. If the venous return to the heart is ob-
structed in any way, the internal jugular vein shares in the general
engorgement and becomes greatly distended. In the lower part
of the neck the vein crosses in front of the first part of the
subclavian artery, and it terminates behind the sternal end of
the clavicle by uniting with the subclavian to form the in-
nominate vein.

Malignant and tuberculous lymph glands frequently become
adherent to the internal jugular vein, and it is not uncommon
for the surgeon to resect a portion of the vessel in order to facilitate
their removal. The vein is first isolated inferiorly, and it is
then divided between ligatures as low down as necessary. The
vein is then dissected upwards — a procedure which is easier
than the reverse method, because numerous tributaries join the
vein in its upper part and render its isolation extremely difficult.
The portion most commonly resected receives the common facial
vein, which must also be ligatured and divided. The rise in
pressure in the internal jugular vein during vomiting is so great
that lateral ligatures may be forced off. Consequently, if the
vein is wounded during an operation, it is much safer to divide
it completely and ligature both the cut ends.

The Common Facial Vein is the most important tributary
of the internal jugular, and it serves as a useful landmark in
removal of the tonsillar and the upper anterior group of the

n8

THE HEAD AND NECK

deep cervical lymph glands (p. 132). It is formed at the lower
border of the submaxillary gland by the union of the anterior
and posterior facial veins (facial and anterior division of temporo-
maxillary vein) ; the former drains the muscles and tissues of

Anterior
auricular glands

Occipital glands

Anterior group of upper^
deep cervical glands "
Posterior group of upper
deep cervical glands

Lower deep cervic
glands, posterior group'

Lower deep
cervical glands,
anterior gr

onsillar gland
Submaxillary salivary
gland
^Common facial vein

""Superior thyreoid vein

hyoid
"~ Internal jugular vein

FIG. 38. — The Veins and Lymph Glands of the Neck. The upper part of
the external jugular vein has been resected. The sterno-mastoid has
been cut across below the point at which it is pierced by the accessory
nerve, and the two cut ends have been turned upwards and downwards,
respectively.

the face, while the latter emerges from the substance of the
parotid gland. The common facial vein passes backwards and
downwards, superficial to the carotid sheath, which it pierces
opposite the greater cornu of the hyoid bone. Its direction is
often altered by enlarged lymph glands. Sometimes it runs

THE NECK 119

horizontally backwards, and sometimes almost vertically down-
wards ; in the latter case it may be mistaken for the internal
jugular vein. It usually receives the superior thyreoid, lingual,
and tonsillitic veins. The last two are found under cover of
the posterior belly of the digastric, and often open directly into
the internal jugular vein. Not infrequently the common facial
ends by joining the anterior jugular vein, which is considerably
increased in size in these cases.

The Superior Thyreoid Vein generally ascends to enter the
common facial, but it may join the internal jugular directly by
crossing the common carotid artery.

The Middle Thyreoid Vein, which appears from under cover
of the anterior belly of the omo-hyoid, enters the internal jugular
vein after piercing the anterior aspect of the carotid sheath
(p. 120).

The Common Carotid Artery.— On the right side, the
common carotid artery arises from the innominate artery behind
the sterno-clavicular joint ; on the left side, it arises from the
arch of the aorta and lies in the superior mediastinum for
ij inches. The course of the artery in the neck can be mapped
out by a line drawn from the sterno-clavicular joint to a point
midway between the angle of the mandible and the mastoid
process. Opposite the upper border of the thyreoid cartilage,
which lies at the level of the fourth cervical vertebra, the common
carotid ends by dividing into the internal and external carotid
arteries. As it lies in front of the carotid tubercle (p. 107),
the artery is crossed by the anterior belly of the omo-hyoid,
which is running upwards, forwards, and medially.

Ligature of the common carotid artery above the omo-hyoid is
performed for congenital hydrocephalus (Stiles), or for aneurism
of the innominate artery. Temporary occlusion of the vessel by
Crile's method may be carried out in this part of its course as a
preliminary step to extensive operations on the mouth or throat.
This proceeding is dangerous in elderly people, since it may
induce cerebral softening (p. 120), and in these patients the
external carotid should be selected. The incision may be made
along or obliquely across the anterior border of the sterno-
mastoid. The skin, superficial fascia, and the platysma are
divided, and the investing layer of the deep cervical fascia is
cut through at the anterior border of the sterno-mastoid, thus
allowing the muscle to be retracted to the lateral side. The
omo-hyoid, which is now exposed, is an important landmark,

8c

120 THE HEAD AND NECK

as it indicates the proximity of the vessel. It is drawn down-
wards and medially, bringing the middle thyreoid veins into view,
and the carotid sheath is opened on its medial side to avoid
injuring the internal jugular vein.

Ligature below the omo-hyoid is performed for aneurism of the
distal part of the artery. This operation is more difficult than
the preceding one, because the vessel lies more deeply and is
placed under cover of the sterno-hyoid and sterno-thyreoid
muscles. The incision extends somewhat lower, and after
retracting the sterno-mastoid laterally, the surgeon draws the
omo-hyoid upwards and laterally, and the sterno-hyoid and
sterno-thyreoid downwards and medially.

In both these operations care must be taken not to include
the vagus or the sympathetic trunk in the ligature. If the
sympathetic is injured, unilateral sweating of the head and neck,
contraction of the pupil, and retrogression of the eyeball will
occur on the affected side.

After ligature of the common carotid the collateral circulation
is carried out by (i) the occipital anastomosis ; (2) the thyreoid
anastomosis ; (3) the anastomosis which is established by the
branches of the external carotid arteries, lingual, external
maxillary (facial), etc. across the median plane.

1. In the occipital anastomosis, the ascending branch of the
transverse cervical (p. 126), the profunda cervicis (p. 137), and
the ascending cervical (p. 143), which are all derived from the
subclavian artery, anastomose with the descending and muscular
branches of the occipital artery. This anastomosis takes place
on the superficial and deep surfaces of the semispinalis capitis
(complexus).

2. The thyreoid anastomosis occurs between the superior
and inferior thyreoid arteries in and around the thyreoid gland.
This anastomosis also establishes a connection between the
external carotid and the subclavian arteries.

When the common carotid artery is ligatured, the brain
receives a sufficient, though diminished, blood-supply, owing to
the free anastomosis established by the arterial circle (of Willis).
In infants suffering from hydrocephalus, one common carotid
having been ligatured, the other may be tied after a short
interval without any deleterious effects on the nutrition of the
brain (Stiles), but in adults the ligature of one common carotid
alone may produce cerebral softening.

The External Carotid Artery begins opposite the upper

THE NECK 121

border of the thyreoid cartilage and ends in the parotid gland,
behind the neck of the mandible,, by dividing into the internal
maxillary and superficial temporal arteries. The course of the
artery corresponds to a line drawn from a little below the tip
of the greater cornu of the hyoid bone to the lobule of the
auricle.

In ligature of this part of the vessel the incision may be made
in the natural folds of the neck, either along the anterior border
of the sterno-mastoid or crossing the muscle obliquely. The
superficial coverings are divided, and, in the oblique incision,
the external jugular vein and the great auricular nerve (p. 108)
will be exposed in the upper part of the wound. The deep
fascia is cut along the anterior border of the sterno-mastoid, and
the muscle, which overlaps the artery, is retracted to the lateral
side. Numerous veins (pharyngeal, lingual, and common facial)
cross the external carotid artery to reach the internal jugular
vein. They must be secured before the upward continuation
of the carotid sheath is opened. Care must be taken not to open
the sheath too much to the medial side lest the superior thyreoid
artery be injured as it descends medial to the sheath. The
vessel is ligated between the superior thyreoid and lingual
branches, i.e. a short distance below the greater cornu of the
hyoid bone. In this operation there is little danger of including
the vagus nerve in the ligature, since it is a more intimate
relation of the internal carotid artery, which lies on a deeper
plane.

The upper part of the external carotid artery disappears
by passing under cover of the stylo-hyoid and the posterior
belly of the digastric, but before it does so it is crossed from
behind forwards by the hypoglossal nerve (Fig. 39). Throughout
the rest of its course the artery lies deeply, under cover of the
parotid gland, and is rarely exposed by the surgeon.

The Superior Thyreoid Artery arises from the external
carotid just above the upper border of the thyreoid cartilage,
and runs downwards and forwards, disappearing under cover
of the omo-hyoid and the sterno-thyreoid to supply the thyreoid
gland (p. 167). It may be ligated near its origin by an incision
similar to that employed for ligature of the external carotid.
The superior cornu of the thyreoid cartilage is the deep surgical
guide to the vessel. The branches are (i) the Superior Laryngeal
Artery, which pierces the thyreo-hyoid membrane at the posterior
border of the thyreo-hyoid muscle, in company with the internal

122 THE HEAD AND NECK

laryngeal nerve (p. 159) ; (2) the Crico-thyreoid Artery (p. 162) ;
and (3) a branch of supply to the sterno-mastoid (p. 115).

The Lingual Artery (p. 145) arises from the external carotid
opposite the greater cornu of the hyoid bone. It makes an
upward loop, and then passes deep to the posterior border of
the hyo-glossus muscle, and gains the submaxillary region.
This loop permits the hyoid bone to be elevated without
putting an undue strain on the vessel. In ligature of the lingual
artery, preparatory to removal of the tongue, the first part of
the vessel is usually selected, as it is then secured before its
important branches to the tongue and the palatine tonsil are
given off. The incision is practically the same as for ligature
of the external carotid (p. 121). The greater cornu of the hyoid
bone is the superficial guide to the vessel, and the posterior
belly of the digastric is a convenient guide to the depth which
has been reached. Immediately below the muscle the hypo-
glossal nerve (p. 124) crosses the arterial loop, and tributaries of
the internal jugular vein often obscure both the nerve and the
artery.

The External Maxillary (Facial) Artery arises from the
external carotid immediately above the lingual or occasionally
by a common trunk with it. Immediately after its origin it
passes upwards under cover of the stylo-hyoid and the posterior
belly of the digastric and enters the submaxillary region (p. 147).
The procedure already described for ligature of the lingual
artery may be followed in ligating this vessel.

The Occipital Artery arises from the posterior aspect of the
external carotid artery at the same level as the external maxillary
(facial). It runs upwards and backwards along the lower border
of the posterior belly of the digastric, and disappears under
cover of the mastoid process and the muscles attached to it.
In the first part of its course it crosses superficial to the internal
jugular vein and the accessory nerve. As it crosses the latter
it gives off a branch of supply to the sterno-mastoid, and this,
when cut, may serve to indicate the proximity of the nerve.
Close to its origin the occipital artery is crossed by the hypo-
glossal nerve, which descends along the lateral side of the in-
ternal carotid and bends sharply forwards at this point (Fig. 39).

The Accessory (Spinal Accessory) Nerve leaves the skull
through the middle compartment of the jugular foramen. At
first it lies between the internal carotid and the internal jugular
vein. Opposite the transverse process of the atlas the nerve,

THE NECK

123

crosses the vein and runs downwards and laterally. It is
crossed by the occipital artery, and i| inches below the tip of
the mastoid process it pierces the sheath of the sterno-mastoid.

External maxillary artery
External carotid artery | Ascending palatine artery

Facial nerve
Posterior auricular

Internal carotid
artery

Accessory nerve
Occipital artery

Hypoglossal nerve

Internal jugular vein

Vagus nerve

Common facial vein, cut

•fer. descendens hypoglossi

Rainus communicans

cervicalis

Great auricular nerve
Common carotid artery

Sterno-mastoid artery -
External jugular vein --

Sterno-mastoid,
clavicular head

External maxillary
artery

f Nerve to mylo-hyol
Mylo-hyoid fe,an(
Submaxillary salivary
Stylo-hyoid

Anterior belly of digastric
o-glossus

Common tendon of digastric
ngual artery
Hyoid bone
Nerve to thyreo-hyoid
Internal laryngeal nerve
Superior thyreoid artery
Thyreo-hyoid muscle
Thyreo-hyoid membrane
Laryngeal prominence

External laryngeal nerve
Omo-hyoid
Sterno-hyoid

Anterior jugular vein

FIG. 39. — The Side of the Neck. The anterior border of the sterno-mastoid
has been retracted in order to expose the underlying vessels and nerves.

Accompanied by a branch from the occipital artery, it enters
the muscle, which it supplies. Its subsequent course is de-
scribed on p. 125.

The Hypoglossal Nerve lies deeply, under cover of the

124

THE HEAD AND NECK

parotid gland, in the upper part of its course, and it descends
between the internal jugular vein and the internal carotid
artery. It appears at the lower border of the posterior belly

of the digastric, and
bends forwards almost
at right angles, hooking
round the occipital artery.
It crosses superficial to
the internal and external
carotid arteries and to
the loop formed by the
lingual, and it is itself
crossed by the lingual
veins. It runs forwards,
a little above the level
of the hyoid bone, and
disappears under cover
of the posterior belly of
the digastric (Fig. 39).
It reappears above the
common tendon of the
digastric, lying on the
hyo-glossus. On reach-
ing the posterior border
of the mylo-hyoid, the
nerve enters the inter-
muscular space between
this muscle and the hyo-

FlG. 40. — Diagram to illustrate the Path of gloSSUS (p. 154), and SO

the Efferent Fibres from the Central reacheS the muscles of

Nervous System to the Sympathetic ^ , . , .

Ganglia. The cervical and the upper the tongue, which it SUP-

portion of the thoracic part of the sym- plies. In the Superficial

pathetic trunk are shown. In the cervical par£ Of fts course it gives

region, grey rami communicantes alone _. , ,. , *

are present, but in the thoracic region ot± a descending branch

white rami communicantes are present in (p. 154) and the nerve

addition. The posterior rami (primary Qf supply to the thyreo-

divisions) of the spinal nerves are not , . ,

shown in the diagram.

hyoid.

The Sympathetic
Trunk in the neck is embedded in the posterior wall of the
carotid sheath, and lies posterior to the common and internal
carotid arteries and medial to the vagus nerve. It possesses
three ganglia, and these send afferent fibres to the spinal

THE NECK 125

medulla and efferent fibres to the blood-vessels, sweat-glands,
etc., of the head, neck, and upper limb.

The anterior ramus (primary division) of each spinal nerve
receives from the sympathetic a grey ramus communicant, in
which afferent fibres are conveyed to the central nervous system.
Efferent fibres from the spinal medulla to the sympathetic are
contained in white rami communicantes , which are only present
in certain regions ; they connect the anterior rami of T. i or
T. 2 — L. i or L. 2, and those of S. 2 and 3 or S. 3 and 4 to the
corresponding sympathetic ganglia. As the cervical ganglia
of the sympathetic trunk receive no white rami communicantes,
the efferent fibres which they distribute leave the spinal medulla
in the highest white ramus communicans, and then ascend
through the sympathetic trunk into the cervical region (Fig. 40).
They are, therefore, involved in complete transverse lesions of
the spinal medulla, above the level of the first thoracic segment.
Such lesions are accompanied by paralysis of the dilatator
pupillae muscle, which is supplied by fibres which leave the
superior cervical ganglion of the sympathetic trunk and enter
the skull with the internal carotid artery. As a result of this
paralysis, the pupil on the affected side is small and does not
react to light.

The Posterior Triangle of the Neck.— The upper part
of the posterior triangle of the neck is exposed during the re-
moval of the postero-superior group of the deep cervical lymph
glands ; its lower part is exposed (i) in operations on the postero-
inferior group of lymph glands, (2) in operations on the brachial
plexus, (3) in ligature of the third part of the subclavian artery,
and (4) in the removal of a cervical rib. The base of the triangle
is formed by the middle third of the clavicle, and its anterior
and posterior boundaries by the posterior border of the sterno-
mastoid and the anterior border of the trapezius respectively.
The layers of fascia which form the roof and cover the floor of
the triangle are described on pp. in, 112. Between them a
varying amount of loose fat is found, in which lie the accessory
nerve, the descending branches of the cervical plexus, and the
termination of the external jugular vein.

The Accessory Nerve emerges from the sterno-mastoid
at the junction of the upper and middle thirds of its posterior
border, and runs obliquely downwards and laterally across the
posterior triangle. About two inches above the clavicle, or on
a level with the seventh cervical spine, it disappears under cover

126 THE HEAD AND NECK

of the anterior border of the trapezius, in which it terminates.
Below, and parallel to the accessory nerve, the branches to the
trapezius from C. 3 and C. 4 cross the triangle. In operations
in this region they may be mistaken for the accessory nerve,
and, as it is important that the latter should be preserved, the
surgeon may require to nip the nerve with dissecting forceps to
make certain of its identity. In the case of the accessory, the
upper fibres of the trapezius will contract and the shoulder will
be elevated (p. 6) ; in the other case, the lower fibres of the
trapezius will respond, but the result cannot be appreciated
from in front. Both these motor nerves pass to the deep surface
of the trapezius, and in this way they can be distinguished from
the posterior supra -clavicular (supra -acromial) nerves, which
run superficial to the muscle (Fig. 35).

In its lower part the space is crossed by the posterior belly
of the omo-hyoid, which runs medially and slightly upwards.
Laterally, the muscle is completely hidden by the clavicle, but as
it approaches the sterno-mastoid it rises to a higher level. When
operating in this region the surgeon often finds it convenient
to cut through the fascial sheath of the omo-hyoid (p. in) so
that the muscle may be retracted upwards. If necessary, it may
be cut away, without any subsequent disability.

The Transverse Cervical Artery arises from the thyreo-
cervical trunk (thyreoid axis, p. 143), and runs laterally, deep to
the sterno-mastoid, but in front of the prevertebral fascia and
the scalenus anterior. It then crosses the floor of the posterior
triangle under cover of the posterior belly of the omo-hyoid.
In enlargement of the lymph glands in this region the transverse
cervical artery is increased in size, and the haemorrhage which
occurs during their removal is due to the division of its branches.

The Transverse Scapular (Suprascapular) Artery has a
similar origin and course, but it lies at a lower level. It is placed
behind the clavicle, and crosses in front of the subclavian
artery and the brachial plexus. The veins which accompany
these arteries join the external jugular as it lies in front of the
third part of the subclavian artery (p. 131).

Exposure of the lower part of the Posterior Triangle. — A
curvilinear incision, extending downwards along the sterno-
mastoid and laterally along the clavicle, gives the best view of
the lower part of the posterior triangle. When the flap is turned
backwards the external jugular vein is exposed, near the apex
of the wound, as it pierces the deep fascia (p. 109).

THE NECK 127

In order that the important nerves may not be injured, the
loose fat which lies on the floor of the triangle is best removed
by the finger, covered with gauze.

In exposing the brachial plexus after injuries by gunshot
wounds, or in obstetrical paralysis, etc., the sterno-mastoid is
drawn forwards and the scalenus anterior is then brought into
view. If there is little scar tissue the nerves may be looked
for at the lateral border of the scalenus anterior, from behind
which they emerge. The prevertebral fascia must be incised,
and C. 5 is found about an inch above the posterior belly of the
omo-hyoid. But if much scar tissue is present it is easier and
safer to look for the supra-scapular nerve first. It will be found
by blunt dissection in the angle between the clavicle and the
anterior border of the trapezius, and it can then be traced medi-
ally to its origin from the upper trunk of the plexus, formed
by the union of C. 5 and C. 6.

These nerves can be followed to the point where they emerge
from under cover of the scalenus anterior, and the lower nerves
of the plexus can then be identified. C. 8 and T. i unite to form
the lower trunk behind the scalenus anterior. This nerve trunk
generally lies just below the omo-hyoid and above the subclavian
artery, but sometimes it is found behind the artery, occupying
the posterior part of the subclavian groove on the upper surface
of the first rib.

An oblique incision, running from the junction of the middle
and lower thirds of the posterior border of the sterno-mastoid
to the angle between the trapezius and the clavicle, may also
be used in the exposure of the brachial plexus. If necessary,
it may be prolonged across the clavicle, and the bone may be
divided temporarily. The external jugular vein is exposed and
ligatured, and the omo-hyoid is freed and retracted upwards or
downwards.

If end to end union is found to be impossible after excision
of the scar tissue in a torn cervical nerve, the proximal end of
the injured nerve may be implanted directly into the next nerve
of the series.

Bilateral Ulnar Paresis and Analgesia sometimes supervene if a person,
who usually sleeps on one or other side, falls asleep lying on his back. The
explanation is to be found in the close relationship between the first thoracic
nerve (or the lower trunk) and the first rib, for the weight of the shoulders
falling backwards is sufficient to cause pressure on the nerve. For a similar
reason, symptoms resembling those produced by a cervical rib (p. 100) may
occur in patients who are restricted to a dorsal decubitus after abdominal

128 THE HEAD AND NECK

operations, or if the arms have been allowed to hang down unsupported from
the operating table. Further, recent observations have shown that symptoms
ascribed to the presence of a cervical rib may in reality be due to the first
(thoracic) rib. Moreover, the first rib has been partially removed in some
cases, with complete disappearance of the symptoms.

Cervical Rib. — The ventral portion of the transverse process

FJG. 41. Bilateral Cervical Ribs. Viewed from behind. The cervical

ribs are considerably foreshortened.

of a cervical vertebra is homologous with a thoracic rib, and is
termed the costal element. In the case of the sixth and seventh
cervical vertebrae the costal elements frequently develop from
independent secondary centres of ossification, and occasionally
they undergo abnormal development so as to form cervical ribs.
The condition may be unilateral or bilateral, and varies from a

THE NECK 129

simple exostosis of the costal element to a fully formed rib,
articulating, by complete joints, with the transverse process and
body of the seventh cervical vertebra. The ventral extremity of
the rib may reach the sternum, or it may articulate or fuse with
the first thoracic rib ; when small, it may be attached to the first
thoracic rib by a fibrous band, or it may present a free extremity.
Radiograms, taken in an antero-posterior plane, frequently fail
to show a cervical rib when one is present, owing to foreshorten-
ing consequent on its downward and forward direction.

When the rib is well developed, both the subclavian artery
and the lower trunk of the brachial plexus groove its upper and
anterior surface. In these cases the artery occupies a higher
position than normal, and its pulsations are readily felt. The
diagnosis of aneurism may suggest itself, especially as the radial
pulse on the affected side is weakened, but this sign disappears
when the limb is elevated. Very often the rib is too short to sup-
port the artery, and is crossed by the nerve trunk only. Even
in these cases the artery lies at a higher level than normal.

Muscular attachments are determined by the size of the rib.
When it is complete, or nearly so, it receives the insertions of
the scalenus anterior and the scalenus medius, and intercostal
muscles occupy the space between it and the first thoracic rib.

A cervical rib may be present without causing any symptoms.
Frequently, however, the pressure on the lower trunk of the
brachial plexus is such that the removal of the rib must be under-
taken. The nervous symptoms are described on p. 100.

Removal of a Cervical Rib. — In this operation it is important
that the whole area should be widely exposed. This can be
effected by a curvi-linear incision passing down the posterior
border of the sterno-mastoid and turning laterally along the
clavicle. The external jugular vein is secured as it pierces the
deep fascia, and the posterior belly of the omo-hyoid is removed.
The fat and lymph glands which lie on the floor of the posterior
triangle are dissected away, and the prevertebral fascia is
exposed. At this stage the dorsalis scapulae nerve (to the
rhomboids) and the long thoracic nerve (of Bell) (p. 131) are
secured and traced up to their point of exit from the scalenus
medius. They are then retracted to one or other side, and the
lateral or posterior border of the scalenus medius is defined. The
rest of the operation is carried out behind the muscle, and in
this way the brachial plexus and the subclavian artery, which
are displaced forwards, need not be exposed. The scalenus

130 THE HEAD AND NECK

medius is next separated from the upper surface of the rib in a
forward direction, and the bone is divided as close to its proximal
extremity as possible. The distal portion is drawn laterally,
and separated from the intercostal muscles. It is then traced
forwards as far as possible and again divided.

The same method may be adopted in the removal of a first
thoracic rib, if it is producing pressure symptoms, but great care
must be exercised to avoid injuring the pleura.

The Muscular Floor of the Posterior Triangle is formed in
its upper part by the splenius capitis, the fibres of which pass
forwards and upwards from the vertebral spines and ascend
under cover of the upper part of the sterno-mastoid to reach
the mastoid process. Below and parallel to the splenius capitis,
the levator scapula (Fig. 42) runs downwards and laterally from
the transverse processes of the upper cervical vertebrae to reach
the medial (superior) angle of the scapula. At a lower level
the scalenus medius and posterior form the floor of the triangle.
They are usually more or less blended with one another, and
their fibres have a more downward inclination, as they are in-
serted into the posterior portions of the first and second ribs re-
spectively. In their lower part they are crossed by the trunks
of the brachial plexus and the subclavian artery.

The Scalenus Anterior is usually completely under cover
of the posterior border of the sterno-mastoid, but it is exposed
when that muscle is retracted medially. It arises from the
anterior tubercles of the transverse processes of the intermediate
cervical vertebrae, and runs downwards and slightly laterally,
to be inserted into the scalene tubercle on the inner margin of
the first rib. Like the muscles in the floor of the posterior
triangle, it lies behind the prevertebral fascia, by which it is
separated from the posterior belly of the omo-hyoid.

The Phrenic Nerve arises mainly from C. 4, but it usually
receives additional fibres from C. 3 and €.5. It runs vertically
downwards in front of the scalenus anterior but behind the
prevertebral fascia, and it is overlapped by the internal jugular
vein. Owing to the obliquity of the muscle, the phrenic nerve
crosses the scalenus anterior from its lateral to its medial border

(Fig- 44).

The nerves of supply to the levator scapulae and the scalene
muscles all lie deep to the prevertebral fascia (p. 112).

The Dorsalis Scapulae Nerve (N. to the Rhomboids) arises
from C. 5, as it lies between the scalenus anterior and medius,

THE NECK 131

and passes backwards through the scalenus medius, emerging
on its lateral surface, under cover of the posterior belly of the
omo-hyoid. It disappears by passing between the levator
scapulae and the scalenus posterior.

The Long Thoracic Nerve (of Bell) arises by three roots,
from C. 5, 6, and 7. The first root arises in common with the
dorsalis scapulae nerve, but separates from it in the scalenus
medius and appears on the surface of the muscle at a slightly
lower level. The second root also pierces the scalenus medius,
and unites with the first to form a common trunk, which runs
downwards to the axilla behind the main part of the plexus.
The root from C. 7 arises near the lateral border of the scalenus
medius, and enters the axilla before uniting with the rest of the
nerve.

Both the dorsalis scapula and the long thoracic nerves lie behind
the prevertebral fascia, and, in removal of the poster o-inferior group
of the deep cervical lymph glands, they are in no danger so long as
the fascia is not disturbed. In operations in which the pre-
vertebral fascia requires to be opened, e.g. repair of brachial
plexus, these two nerves should be found and isolated as soon
as the fascia is incised.

The Third Part of the Subclavian Artery commences
at the lateral border of the scalenus anterior, and extends down-
wards and laterally to the outer border of the first rib. Near
its termination, the artery lies completely behind the clavicle.
If pressure is exerted in a downward, medial, and backward
direction in the angle between the posterior border of the sterno-
mastoid and the clavicle, the subclavian artery can be compressed
against the first rib.

In making the incision for the purpose of ligaturing this part
of the subclavian artery, the surgeon draws the skin down over
the clavicle and incises it along the bone. When the skin is
allowed to retract upwards, the deep fascia, which cannot be
drawn down with it, is found exposed but not incised, and
therefore there is no risk of injury to the underlying veins in
making the incision. After division of the deep fascia, the
external jugular vein is found as it crosses the artery to
join the subclavian vein. It receives the transverse cervical
and transverse scapular (supra-scapular) veins from the lateral
side, and these vessels, though often very large, must not be
mistaken for the subclavian vein, which lies at a lower level
and is under cover of the clavicle. The posterior belly of the

132 THE HEAD AND NECK

omo-hyoid is freed and retracted upwards, and the veins., re-
ferred to above, are ligatured. In this process the transverse
scapular (supra-scapular) artery (p. 126) is exposed and pulled
aside. The brachial plexus lies above and to the lateral side of
the subclavian artery, and especial care must be taken to avoid
injuring the lower trunk, which frequently lies behind the vessel.
By retracting the sterno-mastoid medially, the lateral border
of the scalenus anterior, which forms an important landmark,
is brought into view. If the finger is carried downwards along
this border till the tip rests on the scalene tubercle, the pulp of
the finger can feel the pulsations of the artery. As the ligature
is applied close to the lateral border of the scalenus anterior,
great care must be taken lest the pleura, which lies behind the
second part of the artery, be damaged.

In Interscapulo-Thoracic Amputation the clavicle is divided,
or its middle third is resected and the subclavius muscle is
removed. This enables the surgeon to ligate the subclavian
artery and vein and to cocainise the trunks of the brachial plexus.

The Deep Cervical Lymph Glands lie mainly under cover
of the sterno-mastoid, but they project partly into the anterior
and partly into the posterior triangle. They can be subdivided
into four groups, upper and lower posterior and upper and lower
anterior (Stiles).

1. The Upper Posterior Group lies on the roots of the
cervical plexus and extends into the posterior triangle. They
receive afferents from the pharynx, the occipital, and the mastoid
lymph glands, and from the upper anterior group. When these
glands are enlarged, the accessory nerve may be found embedded
in their midst, or lying immediately under the investing layer
of the deep cervical fascia, on the surface of the glandular mass.

2. The Lower Posterior Group lies in relation to the posterior
belly of the omo-hyoid and superficial to the prevertebral fascia.
They may be involved alone in ascending infection from the
axillary glands, as in malignant disease, or they may be attacked
by a descending infection from the upper groups, or by a lateral
spread from the lower anterior group.

3. The Upper Anterior Group is situated around the upper
part of the carotid sheath, but a few of the glands lie within the
sheath in close contact with the internal jugular vein. They
receive afferents from the interior of the cranium, the pharynx,
mouth, nose, upper part of larynx, etc., either directly, or in-
directly from the submental and submaxillary lymph glands.

THE NECK

133

The tonsillar lymph gland is placed in the angle between the
common facial and the internal jugular veins. It is very con-
stant in position, and is very early involved in tuberculous

Anterior^
auricular gland

Occipital gland

Anterior group of uppe
deep cervical gland
Posterior group of uppe _
deep cervical glands'

Lower deep cervical
glands, posterior gr

Lower deep
cervical glands,
anterior gr

isillar gland

ubmaxillary salivary
gland
vCommon facial vein

•Superior thyreoid vein
•Omo-hyoid

'* Internal jugular vein
Sterno-hyoid

FIG. 42. — The Veins and Lymph Glands of the Neck. The upper part of
the external jugular vein has been resected. The sterno-mastoid has
been cut across below the point at which it is pierced by the accessory
nerve, and the two cut ends have been turned upwards and downwards,
respectively.

disease (p. 189). It receives afferents directly from the palatine
tonsil.

4. The Lower Anterior Group lies in relation to the lower
part of the carotid sheath and the scalenus anterior. Some of
the members of this group are placed within the sheath ; others
lie between the scalenus anterior and the cervical pleura ; and

9a

134 THE HEAD AND NECK

the remainder are in contact with the anterior surface of the
muscle. They may be infected secondarily to the upper anterior
and lower posterior groups, or they may be alone involved
following ascending infection from the mediastinal lymph
glands.

Surgical Approach to the Deep Cervical Lymph
Glands. — If, when the upper group is involved, the enlarged
lymph glands do not- extend into the posterior triangle, an
oblique incision running downwards and forwards in the skin
creases of the neck, towards the laryngeal prominence,, may
be utilised. It should not approach nearer than one finger's
breadth to the angle of the mandible, lest the cervical branch
of the facial nerve be cut, with subsequent paralysis of the
muscles of the lower lip (p. 108).

If the enlarged glands extend far into the posterior triangle
an inverted ^-shaped incision (Stiles) gives the best access.
Starting near the greater cornu of the hyoid, it passes obliquely
upwards towards the mastoid process and is then carried down-
wards along the anterior border of the trapezius. The latter
part of the incision may be carried as far as the clavicle, if
necessary, and, as it passes through the investing layer of the
deep cervical fascia, care must be taken to avoid injuring the
accessory nerve (p. 125).

In both cases the external jugular vein is liable to injury. It
is exposed when the margins of the oblique incision are undercut,
or when the curved flap, which includes the platysma, is turned
downwards. It is advisable to secure the vein at once, as high
up and as low down as possible. The intervening portion can
then be removed, usually together with the great auricular nerve
(p. 108). Excessive bleeding at this stage is suggestive of
glandular pressure on the internal jugular vein, with consequent
engorgement of the collateral channels of venous return. In the
subsequent stages of the operation the structures most liable
to injury are the internal jugular vein and the accessory nerve.
They are therefore identified as soon as the skin flaps, along
with the investing layer of the deep fascia, have been under-
mined and retracted. In tuberculous lymph-adenitis the caseous
glands are commonly adherent to the carotid sheath, and this
structure should be opened below the diseased area. The
internal jugular vein can then be dissected free without injury,
while the caseous glands and the adherent sheath can be re-
moved. In malignant disease, however, the vein and sometimes

THE NECK 135

the artery have to be sacrificed. When ligatures are being
applied, prior to resection, care must be taken not to include
the vagus nerve. Should the common facial vein be wounded
near its termination, the haemorrhage may be so great, owing
to its proximity to the internal jugular, as to suggest injury of
the larger vessel. In ligation of the common facial, the ligatures
must be placed so as to control its numerous tributaries (superior
thyreoid, etc., p. 119).

The accessory nerve is found in the upper part of its
course by dissecting the deep fascia off the anterior border
of the sterno - mastoid, i J inches below the tip of the
mastoid process. It pierces this fascia to reach the muscle.
The branch from the occipital artery to the sterno-mastoid
(p. 122) serves as a convenient guide, and, after the nerve has
been found in this situation, it is traced upwards and forwards
through the glands till it disappears under cover of the posterior
belly of the digastric (p. 122). Improved access to the highest
group of lymph glands, which lie under cover of the parotid
gland and the mastoid process, may be obtained by dividing
the anterior part of the insertion of the sterno-mastoid trans-
versely. These lymph glands lie superficial to, and slightly
lower than, the occipital artery.

The position of the accessory nerve in the posterior triangle
of the neck is described on p. 125. When the lymph glands of
the posterior triangle are involved, the nerve must be exposed
before they are attacked, as it is the most important structure
in the region. If a little dissection amongst the enlarged glands
at the middle of the posterior border of the sterno-mastoid
fails to expose the nerve, it must be sought for at the point where
it disappears under cover of the trapezius (p. 125), and then
traced upwards through the mass. The enlarged glands are apt
to alter the course of the nerve, and it runs grave risk of injury
if a prolonged search for it is made amongst them.

When the lower groups are involved, good exposure is obtained
by a long oblique incision extending from the junction of the
middle and lower thirds of the anterior border of the trapezius
almost to the jugular (suprasternal) notch. The terminal part
of the external jugular vein and the accessory nerve are exposed,
— the latter as it disappears under cover of the trapezius in the
posterior part of the wound. In removing the glands, the
surgeon does not require to cut through the prevertebral fascia,
and, as a result, the nerves of supply to the levator scapulae

96

136 THE HEAD AND NECK

and the rhomboids,, the phrenic nerve and the long thoracic
nerve (of Bell) — which all lie behind the fascial sheet — are
perfectly safe. When the glands are being dissected from under
the posterior belly of the omo-hyoid, haemorrhage may occur
from the enlarged branches of the transverse cervical artery
which supply them.

The removal of the lower anterior group of lymph glands is
fully described on p. 141.

When all the deep cervical lymph glands are involved, the large
inverted J -shaped incision (p. 134) may be utilised, or it may
be converted into an inverted U. This operation is greatly
simplified by dividing the sterno-mastoid transversely below
the level of the accessory nerve and turning the cut ends upwards
and downwards. The internal jugular vein and the accessory
nerve are satisfactorily exposed by this procedure. Behind the
prevertebral fascia, the ascending cervical artery, which is a
branch of the inferior thyreoid, runs upwards in front of the
scalenus anterior on the medial side of the phrenic nerve and
gives numerous branches to the deep cervical lymph glands.

Posterior Aspect of Neck.— This region of the neck is
exposed by the surgeon in the operation for the division of the
posterior rami (primary divisions) of the cervical nerves, a
proceeding which is called for in certain cases of Spasmodic
Torti-collis. A vertical incision is made from a point midway
between the mastoid process and the external occipital protuber-
ance downwards to the level of the superior border of the scapula.
The line of this incision overlies the posterior triangle of the
neck above and the trapezius below. After the skin and fasciae
have been incised and undercut on each side, the splenius is
exposed in the upper part of the wound and can be recognised
by the direction of its fibres, which run upwards and laterally.
In the lower part of the wound the splenius is covered over by
the trapezius. The latter muscle is cut through in the line of
the original incision and dissected off the surface of the lower
part of the splenius. The whole of the splenius is next divided
in the same line, and the two parts of the muscle are undermined
and retracted. The longissimus capitis (trachelo - mastoid),
which is a thin muscular sheet closely applied to the deep surface
of the splenius, is usually retracted along with the lateral part
of the muscle. When this is the case, the vertical fibres of the
semispinalis capitis (complexus) are completely exposed, with
the superficial branches of the ramus descendens of the occipital

THE -NECK

137

artery and their venae comites on its surface. The semispinalis
capitis is split along the whole length of the incision, and the two
parts are undermined and retracted. The deep branch of the
ramus descendens and the numerous veins which accompany

Inferior

3rd and 4th cervical nerves
posterior rain

Semispinalis cer

Superior oblique
Rectus capitis
posterior major
ist cervical nerve,
posterior ramus
Communication
between ist and
2nd cervical nerves
Greater occipital
nerve

. Articular process

_ _ . Semispinalis capitis

Longissimus

capitis

Splenius

_ f Trapezius

FIG. 43.-

-Exposure of the Posterior Ranii (Primary Divisions) of the
Upper Cervical Nerves.

it should now be secured. They are found running downwards
on the deep surface of the semispinalis capitis (complexus), and
the arteria profunda cervicis, which ascends between the same
muscular layers to anastomose with the ramus descendens
(p. 120), may also be controlled at this stage. The semispinalis
cervicis (colli) is now exposed in the lower part of the wound ,

138 THE HEAD AND NECK

and its fibres can be seen extending upwards to the spine of the
second cervical vertebra. Along its lateral border the articular
processes of the cervical vertebrae can be made out, while the
muscular sub-occipital triangle is exposed in the upper part of
the incision (Fig. 43).

The lower boundary of the sub-occipital triangle is formed by the inferior
oblique, which extends from the spine of the second cervical vertebra to the
transverse process of the atlas. The medial boundary, formed by the rectus
capitis posterior major, extends from the spine of the second cervical vertebra
upwards to the occipital bone ; and the lateral boundary, formed by the
superior oblique, ascends from the transverse process of the atlas to the
occipital bone. The floor of the triangle is formed by the posterior arch of
the atlas and the posterior atlanto-occipital membrane (ligament). The
vertebral artery lies on the lateral part of the floor. After leaving the fora-
men in the transverse process of the atlas, it bends round the posterior aspect
of the lateral mass prior to piercing the posterior atlanto-occipital membrane
and the dura mater. In this part of its course the artery is separated from
the posterior arch of the atlas by the posterior ramus (primary division) of
the first cervical nerve, which at once breaks up into small branches to
supply the surrounding muscles.

The most important landmark at this stage is the greater
occipital nerve. It emerges at the lower border of the inferior
oblique and at once turns upwards and medially into the re-
tracted flap (Fig. 43). At the lower border of the inferior
oblique the greater occipital nerve gives off a communicating
branch, which enters the sub-occipital triangle and joins the
first cervical nerve. It is essential that this branch should be
found and traced, as in this way the first cervical nerve can be
found with a minimum of risk to the vertebral artery. The
first cervical and the greater occipital nerves — the latter repre-
sents the posterior ramus (primary division) of C. 2 — are cut away
as close to their origins as possible.

The lower nerves are embedded in the fascia which separates
the semispinalis capitis (complexus) from the semispinalis
cervicis. If this fascia is left behind when the former muscle
is undermined, the nerves will be found on the surface of the
latter (Fig. 43) ; if not, they will be found on the deep surface
of the semispinalis capitis. They should be traced to the
lateral border of the semispinalis capitis and there cut away,
close to the articular processes.

The Deep Triangle of the Neck is a well-defined region
which is of great importance to the surgeon, more especially
on the left side. It lies behind the lower part of the carotid
sheath and is bounded medially by the longus colli and laterally
by the scalenus anterior. The two muscles converge above

THE NECK 139

on the transverse process of the sixth cervical vertebra to form
the apex of the triangle, while, inferiorly, the space is bounded
by the first part of the subclavian artery. The surgeon deals
with this region (i) in operations for ligature of the vertebral
artery, (2) in cesophagotomy, (3) in excision of cesophageal
diverticula, and (4) in the removal of the lower anterior group
of the deep cervical lymph glands.

In the first three operations mentioned, access is obtained
by an incision along the anterior border of the sterno-mastoid.
After the investing layer of the deep cervical fascia has been cut
through, the muscle is retracted to the lateral side, or its sternal
head may be divided. The sterno-hyoid and sterno-thyreoid
muscles are retracted medially and the pretracheal fascia is
incised to the medial side of the carotid sheath, which is then
retracted laterally. In this way the posterior part of the lateral
lobe of the thyreoid gland is exposed behind the margin of the
sterno-thyreoid. The subsequent procedure differs in the
various operations.

(a) (Esophagotomy. — The oesophagus projects slightly to
the left side from behind the trachea. In the groove between
them, the left recurrent (laryngeal) nerve passes upwards to
disappear at the lower border of the inferior constrictor, and the
descending limb of the inferior thyreoid artery (Fig. 44) runs
downwards to reach the lower pole of the thyreoid gland. The
muscular wall of the oesophagus may be fully exposed by
retracting the trachea, the thyreoid gland, and the depressor
muscles of the hyoid bone, to the right. Posteriorly, the oeso-
phagus rests on the longus colli, in a layer of loose cellular tissue,
but it can easily be freed from the muscle and raised to the
surface. The mucous and submucous coats of the oesophagus
are only attached to the muscular coat by loose areolar tissue,
and hence the tube is very distensible. In performing ceso-
phagotomy, therefore, care must be taken not to work round in
the interval between the coats and so open the muscular coat
on the opposite side in mistake for the mucous coat. To prevent
this mishap, an cesophageal bougie may be passed and cut down
upon at this stage of the operation.

(b) Excision of (Esophageal Diver ticula. — These diverticula
generally occur on the left side, and they occupy the interval
between the oesophagus and the carotid sheath, which is thus
displaced to the lateral side. The entrance to the diverticulum
lies opposite the sixth cervical vertebra, i.e. at the point where

140

THE HEAD AND NECK

the pharynx and oesophagus are continuous. After excision of
the diverticulum, the cesophageal wound is closed horizontally
to avoid the formation of a stricture.

In both of these cesophageal operations a drainage tube is
inserted to prevent any septic infection passing down into the
thorax along the carotid sheath.

Thyreoid gland -V— — —

Longus colli, left border
Left recurrent nerve

Common carotid artery,
cut

Thyreoid cartilage

Scalenus anterior
irenic nerve
Middle cervical ganglion

Ascending cervical artery, cut
Upper trunk of brachial plexus
Sympathetic trunk

irtebral vessels
:alenus medius
Inferior thyreoid artery
Mid. trunk of brachial plexus
Transverse cervical a.

- Transverse scap. a.
Lower trunk of
brachial plexus

..Subclavian
artery

Vagus nerve
Left innominate vein

Inferior cervical ganglion

Subclavian vein
Thoracic duct

Internal jugular vein, cut

FIG. 44. — The Deep Triangle of the Neck.

(c) Ligature of the Vertebral Artery. — In this operation the
deep triangle of the neck is more fully exposed. The vertebral
artery arises from the first part of the subclavian and runs
upwards and backwards behind the carotid sheath. It dis-
appears from view at the apex of the triangle by entering the
foramen in the transverse process of the sixth cervical vertebra.
Shortly before it disappears it is crossed anteriorly by the
inferior thyreoid artery and, on the left side, at a lower level by
the thoracic duct (Fig. 44). From both of these structures it

THE NECK 141

is usually separated by its companion vein, which runs down-
wards in front of it and crosses the subclavian artery to terminate
in the innominate vein. In order to avoid the inferior thyreoid
artery and the thoracic duct, the surgeon applies the ligature as
close as possible to the transverse process of the sixth cervical
vertebra, which forms the most important guide to the vertebral
artery. It may be necessary to tie the vertebral vein before
the artery is ligatured, and it may be impossible to avoid in-
cluding some fibres of the cervical sympathetic, which emerges
from the posterior wall of the carotid sheath in the lower part of
the neck.

(d) In removal of the lower anterior group of the deep cervical
lymph glands good access is essential, and it is obtained by the
oblique (p. 135) or curvi-linear (p. 126) incision already described.

The external jugular vein is exposed and a portion of it is
resected between ligatures. The fascial sheath of the sterno-
mastoid is opened, and the muscle is divided about an inch or
more above the clavicle, and the two cut ends are widely
retracted. This procedure exposes the carotid sheath medially
and, to its lateral side, the scalenus anterior, with the phrenic
nerve and the posterior belly of the omo-hyoid on its surface.
The ascending cervical artery, which supplies many of the glands
of this group, lies close to the medial side of the phrenic nerve.
In order to avoid injuring the phrenic nerve and, on the left side,
the thoracic duct, the glands are best removed by the finger
covered with gauze, but if the knife is used great care must be
exercised. In an old -standing case, where the glands have
become caseous, the scalenus anterior — and even the sterno-
mastoid — may be partially destroyed, and the phrenic nerve is
then more liable to injury.

If the lower anterior group is the only group affected in the
neck, the enlargement is probably due to an ascending infection
from the bronchial lymph glands. As the disease spreads
upwards along the blood-vessels, the lymph glands which lie
along the lower part of the carotid sheath are the first to be
involved. Consequently these glands show a more advanced
stage of the disease than the glands lying along the lateral
border of the scalenus anterior, which will not present the same
number of caseous foci. On the other hand, in descending
infections, the higher glands of the group are the first to be
involved, and the lower glands always show a less advanced
stage of the disease.

142 THE HEAD AND NECK

The Thoracic Duct is closely applied to the left side of the
oesophagus, as it leaves the thorax. It ascends into the neck
for an inch or sometimes an inch and a half above the clavicle,
and then turns laterally behind the carotid sheath and its
contents, but in front of the vertebral and the inferior thyreoid
arteries. It usually crosses in front of the vertebral vein, but
in many cases it passes behind that vessel. On reaching the
medial border of the scalenus anterior, the thoracic duct passes
downwards to enter the postero-lateral aspect of the union of
the subclavian and internal jugular veins of the left side. Some-
times it extends farther laterally on to the surface of the scalenus
anterior, and it usually crosses the phrenic nerve. As it lies
behind the carotid sheath the duct crosses the deep triangle
(Fig. 44), where it lies above the level of the first part of the sub-
clavian artery. Near its termination the thoracic duct lies in
front of the big vessel. It may terminate as a single trunk,
or it may break up into a number of small branches, which join
the internal jugular and subclavian veins independently of one
another. If the duct is injured, its ends must be ligatured if it
is impossible to reunite them.

The thoracic duct drains the lymph from both lower limbs,
the abdominal walls and most of the abdominal viscera, and
the left half of the thorax. In addition it is joined near its
termination by the subclavian trunk, from the left upper
limb, and the jugular trunk, from the left side of the head
and neck. These two trunks, however, may end independently
in the subclavian and internal jugular veins respectively.

The Subclavian Artery arises, on the right side, from the
innominate artery behind the sterno-clavicular joint, and it
arches upwards and laterally, disappearing behind the scalenus
anterior. On the left side, it arises within the thorax from the
arch of the aorta, and it lies behind the left common carotid
artery as it enters the neck. The first part of the artery rests on
the cervical pleura, and extends as far as the medial border
of the scalenus anterior. It forms the oblique lower border of
the deep triangle of the neck, and is covered in front by the
internal jugular vein and the vagus nerve. On the right side
the recurrent nerve arises from the vagus as it crosses the vessel,
and it runs upwards and medially deep to the subclavian and
common carotid arteries. A detailed description of the relations
of this part of the subclavian artery is unnecessary, as it is
rarely ligated by the surgeon.

THE NECK 143

The Thyreo-Cervical Trunk (Thyroid Axis) arises from the
subclavian at the medial border of the scalenus anterior, and at
once divides into the transverse scapular (suprascapular) (p.
126); the transverse cervical (p. 126); and the inferior thyreoid
arteries.

The Inferior Thyreoid Artery runs upwards along the medial
border of the scalenus anterior a.nd behind the carotid sheath
(internal jugular vein). On the left side,, the artery is crossed by
the thoracic duct close to its origin. A little below the sixth
cervical vertebra it turns medially behind the sheath and, at the
point where it makes the bend, it gives off the ascending cervical
artery (Fig. 44). It crosses in front of the vertebral vein and
artery, and at the lateral border of the longus colli it turns
downwards and runs in the groove between the trachea and the
oesophagus, overlapped by the lateral lobe of the thyreoid
gland. The vessel may require to be ligated in operations on
the thyreoid gland, oesophagus, and larynx.

The first part of the subclavian artery also gives off the
vertebral (p. 140) and the internal mammary arteries (p. 503).

The Submaxillary Region of the neck extends upwards,
under cover of the mandible, to the mylo-hyoid line and down-
wards to the hyoid bone. Its roof is formed by the deep surface
of the mandible and by the investing layer of the deep cervical
fascia, which is attached to the lower border of the mandible
above and to the hyoid bone below. In front and behind it is
bounded by the bellies of the digastric, and the fascial roof
blends with the fascial sheath of the muscle, so that a collection
of pus in this neighbourhood is definitely circumscribed. The
submaxillary salivary gland and numerous lymph glands, which
extend from the anterior belly of the digastric in front to the
mandibular angle behind, occupy the area, and during their
examination the head should be flexed in order to relax the
strong fascial roof. The surgeon stands behind the patient and
inserts the tips of his fingers beneath the lower border of the
mandible. By pressing laterally against the bone, he is enabled
to detect even a slight enlargement of the anterior group of
lymph glands. The more superficial glands of the posterior
group, which are intimately related to the submaxillary salivary
gland, may be identified near the angle of the mandible if they
become enlarged.

The floor of the space is formed by the mylo-hyoid in front

144 THE HEAD AND NECK

and above, by the hyo-glossus below and behind,, and by the
middle and superior constrictors of the pharynx, which appear
in the small interval between the posterior belly of the digastric
and the posterior border of the hyo-glossus. These muscles are
useful surgical landmarks, as they can be readily recognised
by the direction of their fibres.

The mylo-hyoid muscle arises from the mylo-hyoid line on the deep surface
of the mandible, and its fibres run downwards and medially. The posterior
fibres reach the hyoid bone, but the anterior fibres are inserted into a fibrous
raphe, which extends from the chin to the hyoid bone in the median plane.
The nerve to the mylo-hyoid, which is a branch from the inferior alveolar
(inferior dental) (p. 183), lies on the superficial aspect of the muscle close
to its origin. The mylo-hyoid may act as an elevator of the hyoid bone,
or, when that bone is fixed, as a depressor of the mandible.

The posterior belly of the digastric arises from the temporal bone under
cover of the mastoid process. It runs downwards, medially, and forwards
towards the greater cornu of the hyoid bone. It crosses the internal jugular
vein, the internal and external carotid arteries, the tenth, eleventh, and
twelfth cerebral nerves, etc., and it is therefore a most important landmark
for the surgeon. It ends in the intermediate tendon, which is bound down
to the greater cornu of the hyoid bone by a slip of deep fascia. The posterior
belly of the digastric is supplied by the facial nerve, which emerges from the
stylo-mastoid foramen close to the origin of the muscle.

The anterior belly of the digastric passes upwards, forwards, and medially
from the intermediate tendon, and is attached to the digastric fossa of the
mandible. It is placed on the superficial aspect of the mylo-hyoid muscle,
and is supplied by the mylo-hyoid nerve.

The digastric muscle may act as an elevator of the hyoid bone, or, if that
bone is fixed, as a depressor of the mandible.

The hyo-glossus, which lies partly under cover of the mylo-hyoid, arises
from the hyoid bone, and its fibres run vertically upwards, medial to the
mandible, forming the lateral surface of the tongue. The origin of the hyo-
glossus extends farther back on the hyoid bone than the insertion of the
mylo-hyoid, and, in consequence, its posterior part can be seen in the angular
interval between the greater cornu of the hyoid bone and the oblique posterior
border of the mylo-hyoid muscle. It is supplied by the hypoglossal nerve.

The constrictor muscles (p. 190) have their fibres directed almost hori-
zontally as they lie in this region.

The Submaxillary Salivary Gland is situated immediately
under the deep fascia and occupies nearly the whole space. It
lies on the mylo-hyoid in front, but posteriorly it rests on the
hyo-glossus, and part of it passes forwards deep to the oblique
posterior border of the mylo-hyoid. It is a soft, lobulated struc-
ture of a pinkish colour, and its lobules may be mistaken for
lymph glands, some of which lie on its superficial aspect. The
submaxillary duct (of Whartori) emerges from the deep part of
the gland and runs forwards, on the upper part of the hyo-
glossus and under cover of the mylo-hyoid, to open into the
floor of the mouth on a small papilla at the side of the frenulum

THE NECK 145

linguae. Between the same muscular layers lie the lingual
nerve above, and the hypoglossal nerve and its accompanying
(ranine) vein below. Both nerves at first run horizontally
forwards.

The Lingual Artery lies on a deeper plane in this part of
its course. On entering the submaxillary region the vessel is
placed deep to the stylo-hyoid and the posterior belly of the
digastric, and it passes under cover of the posterior border of the
hyo-glossus. It then runs forwards horizontally just above
the hyoid bone, giving off its dorsales lingua branches, which
reach the tongue by passing upwards and sinking into the genio-
glossus muscle. A curved incision is employed to expose the
artery. It begins just below the chin, has its mid-point at the
greater cornu of the hyoid bone, and extends to near the angle
of the mandible. It is carried down through the deep fascia,
and the submaxillary gland is then retracted upwards with the
flap. The various muscles are identified by the direction of
their fibres (vide supra), and the hypoglossal nerve is exposed
lying on the hyo-glossus in the angular interval between the
two bellies of the digastric. In the cadaver the fascial slip
which binds the intermediate tendon of the digastric to the hyoid
becomes stretched if the head has been extended for any length
of time, and the tendon is carried upwards, covering the hypo-
glossal nerve. The hyo-glossus is cut through parallel to and
below the nerve (a quarter of an inch above the hyoid in the
cadaver). In life its fibres retract upwards and downwards
and leave the lingual artery exposed, lying on the genio-
glossus.

Acute inflammatory conditions in the submaxillary region
usually arise in connection with the teeth. The pus from an
alveolar abscess may make its way through the periosteum,
either above or below the attachment of the deep fascia to the
mandible (Fig. 45). In the former case it comes to the surface
after perforating the platysma, but in the latter case it enters
the submaxillary region and gives rise to a cellulitic condition
under the deep fascia. Although at first strictly circumscribed,
if not released the pus may follow the course of the lingual
artery or hypoglossal nerve, and, coming into contact with the
carotid sheath, it may give rise to a spreading cellulitis of the
neck (Ludwig's angina). These abscesses should be opened
by Hilton's method in order to avoid injuring the important
structures in this neighbourhood.

10

146

THE HEAD AND NECK

The Submaxillary Lymph Glands may be divided into two
groups :

(a) The anterior group lies in the anterior part of the space,
between the mylo-hyoid and the deep surface of the mandible.
They receive afferents from the anterior part of the tongue and

Maxilla..
Tooth abscess -
Muco-periosteum of palate -

Tongue

Periosteum

Tooth abscess

Maxillary sinus
Inferior meatus

Alveolar abscess
Maxilla

Mucous mem-
brane of cheek

j-Submaxillary duct

Lingual nerve
Genio-glossus
Sublingual gland

Genio-hyoid

Skin '

Digastric, ant. belly

Lymph gland /

Deep cervical fascia

cAbcess

v Mylo-hyoid

Hyoid bone

FIG. 45. — Frontal Section through the Mouth. Four varieties of alveolar
abscess are shown. In the maxilla, on the right side, the pus has spread
laterally, forming an abscess under the mucous membrane ; on the left
side, it has spread medially, forming a palatal abscess. In the mandible,
on the right side, the pus has perforated the bone medial to the attach-
ment of the deep cervical fascia, forming an abscess which is covered by
the fascia and the skin ; on the left side, the pus has perforated the bone
outside the deep fascia, forming an abscess immediately under the skin.

floor of the mouth, from the lower lip and teeth of the lower
jaw, and from the submental lymph glands.

(b) The posterior group lies in relation to the deep and super-
ficial aspects of the submaxillary salivary gland. The superficial
glands receive afferents from the lips, gums, and teeth, ard
from the anterior group. When enlarged they are usually
tuberculous, and the infection can be traced to the teeth. The
deep glands drain the lateral part of the tongue and floor of the

THE NECK 147

mouth. They may become infected secondarily from chronic
tuberculous disease of the superficial glands, but they are
primarily and constantly involved in malignant i disease of
the areas which they drain. The efferents from both groups
terminate in the upper anterior group of the deep cervical
glands (p. 132).

Good exposure of the region is obtained by a large curved
incision similar to that already described for ligature of the
second part of the lingual artery (p. 145). This incision is useful
when a cold abscess points beneath the skin, because the vitality
of the skin immediately over the abscess is not interfered with
when the flap is turned up. If a sinus is present, the incision
may be made straighter so as to excise it entirely. The skin
and platysma are undercut to afford good exposure and to permit
the edges to be brought together subsequently. As soon as
the deep fascia is cut through, the anterior facial vein is exposed,
running downwards and backwards on the surface of the sub-
maxillary salivary gland, but it may be displaced or it may be
embedded amongst the enlarged lymph glands. It enters the
region by piercing the deep fascia at the anterior border of the
masseter muscle, just behind the external maxillary (facial)
artery, and leaves it, as the common facial vein, by passing
superficial to the posterior belly of the digastric. If it is cut,
both ends must be ligatured, as they may give rise to severe
haemorrhage, especially when the vessel is injured near its
junction with the internal jugular vein (p. 118). After the an-
terior facial vein has been dealt with, the superficial lymph
glands may be removed, but they must be distinguished from
the lobules of the salivary gland, which closely resemble them
in appearance.

The removal of the deep lymph glands is complicated by their
relation to the external maxillary (facial) artery. Normally,
the vessel runs first upwards and then forwards and downwards
in a well-marked groove on the deep surface of the salivary
gland, but it may be displaced or surrounded by the lymph glands
when they are enlarged. The salivary gland is turned upwards
and the position of the artery is ascertained, but the vessel is
liable to be wounded as it crosses the inferior border of the
mandible (p. 174). Thereafter the enlarged lymph glands can
be safely taken away. If the glands are malignant, the whole
group (i.e. both superficial and deep), together with the salivary
gland and the portion of the external maxillary (facial) artery

10 a

148 THE HEAD AND NECK

in relation to it, will require excision, possibly with many
neighbouring structures.

Portions of the submaxillary salivary gland may be removed
without the occurrence of a salivary fistula, which only follows
injury to the duct itself or to its larger tributaries.

The Genio-hyoid is a narrow, strap-like muscle, which arises from the
lower part of the mental spine (genial tubercle), and is inserted into the hyoid
bone. It lies immediately under cover of the mylo-hyoid, and is supplied by
the hypoglossal nerve. It acts as an elevator of the hyoid bone or as a de-
pressor of the mandible.

The Genio-glossus muscle arises just above the genio-hyoid, and it widens
out in a fan-shaped manner as its fibres pass backwards. The lowermost
fibres run downwards and backwards to the hyoid bone. In front they are
covered by the genio-hyoid, and behind they disappear under cover of the
hyo-glossus, but between these two muscles they lie in contact with the
mylo-hyoid. The uppermost fibres pass into the tongue, under cover of the
hyo-glossus. The genio-glossus receives its nerve-supply from the hypo-
glossal. The lower and middle fibres protrude the tongue (Fig. 50), while
the upper fibres retract it. When the muscle acts as a whole it depresses
the tongue.

The Stylo-glossus runs downwards and forwards from the styloid process
to the side of the tongue, and in most of its extent it is covered by the
mandible. It helps the anterior fibres of the genio-glossus to retract the
tongue, and is supplied by the hypoglossal nerve.

The Sublingual Salivary Gland lies immediately below the
mucous membrane of the anterior part of the floor of the mouth,
and it forms a small swelling, which can be readily appreciated
by the tip of the tongue. It lies on the surface of the anterior
part of the genio-glossus, and is placed under cover of the man-
dible. It possesses numerous ducts, which open directly into
the floor of the mouth. Occlusion of these ducts gives rise to a
cystic swelling (ranula), which is sometimes bilateral in the
floor of the mouth and lies under the tongue.

The Lingual Nerve (p. 183) runs forwards on the upper part
of the hyo-glossus above the submaxillary duct, which passes
upwards under cover of it anteriorly. It disappears under
cover of the sublingual gland, and sinks into the genio-glossus
to reach the mucous membrane of the tongue. It supplies the
anterior two-thirds of the tongue with ordinary sensation and
with the special sense of taste, the latter through the fibres of
the chorda tympani, which joins the lingual nerve in the infra-
temporal fossa (pterygo-maxillary region).

Development of the Neck. — In the early weeks of fcetal life,
certain transverse ridges, which are known as the visceral or
branchial arches, appear on each side of the neck, and their
inner surfaces project into that part of the foregut (p. 287)

THE NECK 149

which gives rise to the mouth and pharynx. There are six of
these arches, but the lower two do not cause any elevation on the
ectodermal surface. The arches are separated from one another
on the outside by grooves which are termed the visceral clefts,
and on the inside by grooves which are termed the visceral
pouches. The grooves, which never break down in the human
embryo, consist of an outer layer of ectoderm and an inner layer
of entoderm, the two together forming the cleft membrane.
Each arch contains a bar of cartilage, a muscle mass, a nerve,
and an artery.

At the period when the branchial arches develop, the embryo
possesses two ventral aortse, which arise from the truncus
arteriosus, and two dorsal aortas. Each ventral aorta is con-
nected with the dorsal aorta of the same side by six aortic arches,
each of which supplies one branchial arch and the cleft caudal
to it. The external carotid is derived from the distal portion
of the ventral aorta, while the internal carotid represents
the third aortic arch and the distal part of the dorsal aorta.
From this it is clear that branchial fistulse, which develop in
connection with the first or second clefts, must pass deep to
the external carotid but superficial to the internal carotid
artery.

The cartilage of the first arch is known as Meckel's cartilage.
It is almost entirely replaced by the mandible, but its cephalic
extremity forms the greater part of the malleus. The cartilage
of the second arch forms the tip of the styloid process, the stylo-
hyoid ligament, the lesser cornu, and a part of the body of the
hyoid bone. The cartilage of the third arch forms the greater
cornu and the remainder of the body of the hyoid bone, while
the cartilages of the lower arches take part in the formation of
the framework of the larynx.

The muscle mass of the first arch develops into the muscles of
mastication, which are supplied by the nerve of the first arch,
the mandibular division of the trigeminal. The platysma and
the muscles of facial expression are derived from the muscle mass
of the second arch, and are innervated by the facial nerve, which
is the nerve of the second arch. The muscle mass of the third
arch forms the stylo-pharyngeus , and its nerve-supply is obtained
from the glosso-pharyngeal, which is the nerve of the third arch.
It is probable that the constrictor muscles of the pharynx have
a similar origin. Lower down in the series our knowledge of
the history of the muscle mass is less definite. The crico-thyreoid

THE HEAD AND NECK

muscle is derived from the fourth arch, and is supplied by the
external branch of the superior laryngeal, which is the nerve of
that arch. The muscle masses of the fifth and sixth arches form
the intrinsic muscles of the larynx, which are supplied by the
recurrent (laryngeal) nerve — the nerve of these arches. Of the
visceral clefts all but the first, which forms the external acoustic
meatus, disappear entirely. The first visceral pouch forms the
tympanum and the auditory (Eustachian) tube,, so that the
tympanic membrane occupies the site of the cleft membrane.
Remains of the second pouch form the supra-tonsillar fossa
(p. 1 88) and the pharyngeal recess (of Rosenmiiller) (p. 190).

1st Branchial
cleft

2nd Branchial
pouch •

2nd Branchial .
cleft

3rd Branchial
jx>uch •

4th Bran

pouch

4th Branchial .."T
cleft

Separating membrane / /
1st cleft = tympanum i'/
and tube ' ' /

5th Branchial pouch

FIG. 46. — Scheme showing the Branchial Pouches, Clefts and Arches
and some of their derivatives.

The upper two branchial arches develop much more rapidly
than the lower arches, which are soon overlapped and hidden
by the second. The ectodermal covering of the second arch
comes into contact and fuses with the ectoderm caudal to the
fourth cleft. In this way the second, third, and fourth clefts
no longer open on the surface, but instead they open into a
common space termed the cervical sinus. This enclosed ecto-
derm normally disappears, but the persistence of any part of it
may lead to the formation of branchial cysts or fistulse.

A Blind External Branchial Fistula is the most frequent
deformity arising from persistence of the ectoderm which lines
the cervical sinus and normally disappears. It is met with
usually near the anterior border of the sterno-mastoid, but the

THE NECK 151

site of the opening in no way locates the individual cleft which
is at fault. Just as the upper arches and clefts leave more normal
remains than the lower, so it is found clinically that abnormal
remains usually belong to the upper members of the series.

In the human embryo the cleft membrane never breaks down
as it does in fishes, and it is probable that, in cases where a bran-
chial fistula is stated to have been complete, the thin cleft
membrane has been destroyed by the probe or length of fishing-
gut or catgut which has been introduced into the fistula to
examine its track.

This condition can be satisfactorily treated only by dis-
secting out the whole track, for, unless this is done, recurrence is
certain. An incision is made around the fistulous opening, and
it is carried upwards along the anterior border of the sterno-
mastoid as far as is necessary. A fine probe, introduced into the
fistula as it is being dissected, is found to sink gradually through
the superficial fascia and the platysma, and to pierce the deep
fascia about the level of the upper border of the thyreoid
cartilage.

In the majority of cases the fistula is derived from the second
visceral cleft. Consequently, as it is traced upwards, it will be
found to lie superficial to the structures derived from the third
and lower arches, e.g. the internal carotid artery and the glosso-
pharyngeal nerve, but deep to those developed in relation to
the upper two arches. It is therefore crossed by the lingual,
occipital, posterior auricular, and external carotid arteries,
and by the stylo-hyoid ligament and the hypoglossal nerve.
If the fistula extends upwards to the region of the supra-tonsillar
fossa or the pharyngeal recess (of Rosenmuller) (p. 190), it will
pass between the stylo-hyoid and stylo -pharyngeus muscles,
and it has already been explained (p. 149) why the fistula must
pass between the two carotid arteries. In order to remove the
upper part of the fistula entirely, the probe is pushed through
the cleft membrane into the supra-tonsillar fossa or pharyngeal
recess, as the case may be. The fistula is then divided, and,
after the lower part has been removed, the upper part is attached
to the probe and turned inside out by pulling the probe out
through the mouth. In this way the whole of the fistula can
be completely excised.

Branchial cysts may be mistaken for enlarged lymph glands,
but they only occur singly and are unilateral. They contain
a glairy fluid under normal conditions, but if they are infected

152 THE HEAD AND NECK

there may be some difficulty in making a correct diagnosis until
the cyst wall is exposed. Unlike other simple cysts, they are
situated under the deep fascia, and closely resemble a glandular
abscess.

The Anterior Median Line of the Neck.— This area

may be subdivided into (i) a supra-hyoid or lingual region, (2) a
laryngeal region, which extends from the hyoid bone to the
cricoid cartilage, and (3) a tracheal region, lying below the
cricoid cartilage.

The Supra-hyoid Region is triangular in shape. It is bounded
laterally by the anterior bellies of the two digastric muscles
and below by the hyoid bone. The roof is formed by the in-
vesting layer of the deep cervical fascia, which is attached to
the mandible above and to the hyoid bone below, and blends
with the fascial sheaths of the digastric on each side. The
floor of the region is formed by the two mylo-hyoid muscles,
which meet at the median raphe (p. 144).

The submental or supra-hyoid lymph glands are two small
pea-like bodies which lie just above the hyoid bone, and they
can often be felt in the living subject. They receive afferents
from the chin, the central portions of the lower lip, the lower
incisor teeth and gums, the floor of the mouth, and the tip of the
tongue. Abscess or lymph-adenitis in connection with the sub-
mental lymph glands causes a swelling which projects downwards
below the chin, as it is prevented from rising up into the mouth
by the mylo-hyoid muscles. Lingual dermoids, on the other
hand, or cysts and solid tumours in connection with
remains of the thyreo-glossal duct (p. 169), bulge upwards into
the floor of the mouth, since they lie on the deep surface of the
mylo-hyoid muscles. The efferents from the submental lymph
glands pass laterally on the surface of the mylo-hyoids and
open into the submaxillary lymph glands.

Good access to the glands is obtained by a horizontal incision
just above the hyoid bone. It should pass through the deep
fascia, which is undercut so as to expose the anterior bellies of
the digastric, and these muscles act as a guide to the level
of the slightly deeper floor. The glands can then be removed
from the floor of the triangle without trouble.

In the removal of a lingual dermoid a vertical supra-
hyoid incision is carried through the deep fascia to the muscular
floor of the submental triangle, and both edges are undercut.
The median raphe is split and the mylo-hyoid muscles are re-

THE NECK

153

tracted from one another. In the normal condition this pro-
cedure would expose the genio-hyoids lying side by side at the
median plane, but when a dermoid cyst is present it separates
the two muscles. At a deeper level the cyst separates the two
genio-glossi, and its upper surface may be in contact with the
mucous membrane of the anterior part of the floor of the mouth.
The cyst wall is separated from these structures by blunt dis-
section, but it may have to be evacuated prior to removal.
The surgical approach for removal of advanced malignant

Side of tongue
Upper lip

Cut edges of mucous membrane

Mandible, cut

Sublingual gland

^\'~ Lingual nerve
Submaxillary
" duct

Submaxillary
, deep

Mylo-hyoid

Hypoglossal nerve

Mylo-hyoid

Genio-hyoid /
Genio-glossus

FIG. 47. — Surgical approach for the Removal of Advanced Malignant Disease
of the Tongue. The mandible has been divided, lateral to the mental
spine, and the mylo-hyoid has been cut. The operation is described
below.

disease of the back of the tongue, epiglottis, floor of the mouth,
and fauces may be obtained through the supra-hyoid region. A
median vertical incision is made through the lower lip and skin
of the chin and neck down to the hyoid bone. Before the man-
dible is divided, holes are drilled through it on each side of the
symphysis, so that the two halves may subsequently be retained
in position by wiring. The bone is then divided, and the median
raphe of the mylo-hyoids is split. The two halves of the jaw
can now be separated widely, and the mucous membrane of the
floor of the mouth is cut through with scissors, near its reflection

154 THE HEAD AND NECK

on to the gums, from the median plane as far back as the glosso-
palatine arch (anterior pillar of the fauces) on the diseased side.

The cutting of the mucous membrane permits the tongue to
be dragged over towards the healthy side, and exposes, from
before backwards, the sublingual gland lying on the genio-glossus
and the submaxillary (Wharton's) duct, and the lingual nerve
resting on the upper part of the hyo-glossus (Fig. 47). By blunt
dissection the wound is deepened between the hyo-glossus and
stylo -glossus medially, and the mylo-hyoid and stylo -hyoid
laterally, until the hypoglossal nerve is exposed and the hyoid
bone is reached. The hyo-glossus is next cut away from the
hyoid bone, and it is probable that the hypoglossal nerve, on
the superficial aspect of the muscle, and the lingual artery, on
its deep aspect, will be divided at this stage. The submaxillary
duct, the lingual nerve, and the stylo -glossus are next cut
through. If the palatine tonsil and adjoining mucous membrane
are involved, the glosso- palatine arch (anterior pillar of the
fauces) is divided and the diseased area taken away. The actual
removal of the tongue is described on p. 187.

The Depressor Muscles of the Hyoid Bone form a double
layer of muscle, clothing the trachea and larynx. The super-
ficial layer consists of the sterno-hyoid and the anterior belly
of the omo-hyoid, which lies to its lateral side. The deep layer
is formed by the sterno-thyreoid below and by the thyreo-
hyoid above. The former is closely applied to the surface of
the lateral lobe of the thyreoid gland, while the latter is in
relation to the thyreo-hyoid membrane.

The Ansa Hypoglossi lies on the anterior surface of the
carotid sheath opposite the cricoid cartilage. It is formed by
the union of the ramus descendens hypoglossi (p. 124) with &
descending branch from the cervical plexus (C. 2 and 3), and it
supplies all the depressor muscles of the hyoid bone except the
thyreo-hyoid, which is supplied by the hypoglossal nerve
(p. 124).

The Laryngeal Region. — The larynx is covered by the
depressor muscles of the hyoid bone, the lateral lobes of
the thyreoid gland, and the crico-thyreoid muscles. It occupies
a lower position in the adult than it does in the child. In an
infant three months old the cricoid cartilage lies opposite the
fourth cervical vertebra.

The Thyreoid cartilage consists of two expanded laminae, which meet in
front at an angle, the laryngeal prominence, but are widely separated behind.

THE NECK 155

From the upper and lower extremities of the posterior border of each lamina
the superior and inferior cornua project. The latter articulates with the side
of the cricoid cartilage by means of a diarthrodial joint.

The Cricoid cartilage is narrow in front, but it is much deeper posteriorly,
and helps to fill in the gap caused by the wide separation of the laminae
of the thyreoid cartilage. This gap is still further diminished by the two
Arytenoid cartilages, which are situated on the upper border of the posterior
part of the cricoid. These little cartilages are pyramidal in shape, and their
bases articulate with the cricoid by diarthrodial joints. The anterior basal
angle (vocal process) projects forwards and gives attachment to the vocal
fold (true vocal cord), while the lateral basal angle (muscular process) receives
important muscular attachments. At its apex the arytenoid cartilage is
capped by the corniculate cartilage (of Santorini).

The thyreo-hyoid membrane connects the upper border of the
thyreoid cartilage to the upper and posterior part of the hyoid
bone. Its superficial surface is closely applied to the thyreo-
hyoid muscle, while its deep surface is separated from the
epiglottis and the anterior wall of the laryngeal vestibule by a
pad of fat. A bursa is placed between the posterior surface of
the hyoid bone and the upper part of the thyreo-hyoid membrane
to facilitate the movements of swallowing, in which the thyreoid
cartilage ascends behind the hyoid bone. When it is enlarged
the bursa may be mistaken for a thyreo-glossal cyst (p. 169),
as it lies in the median plane, but the laryngeal lymph glands,
which also lie on the thyreo-hyoid membrane, and the possible
presence of accessory thyreoids must be borne in mind when
making the diagnosis.

The conus elasticus (crico-thyreoid membrane} is attached
below to the upper border of the cricoid cartilage, and passes
upwards under cover of the lower border of the lamina of the
thyreoid cartilage. Its upper border is attached in front to
the deep surface of the thyreoid angle, and, behind, to the vocal
process of the arytenoid cartilage. In the rest of its extent it
is free and forms the vocal ligament, which is one of the important
constituents of the vocal fold (true vocal cord).

The epiglottis is a leaf-shaped cartilage, which lies in the
anterior wall of the laryngeal vestibule. Its wide upper end is
free and projects above the hyoid bone in relation to the dorsum
of the tongue, while its narrow lower end is attached to the
deep surface of the thyreoid angle. Anteriorly, the epiglottis is
separated from the thyreo-hyoid membrane by a pad of fat,
and is attached by a ligament to the deep surface of the hyoid
bone. The mucous membrane passes from the dorsum of the
tongue to the front of the upper part of the epiglottis, forming
the floor of a depression, which is divided into two by the glosso-

156

THE HEAD AND NECK

epiglottic fold. These depressions — the valleculce — are bounded
behind by transverse ridges, which extend from the side of the
epiglottis to the lateral walls of the pharynx. The floor of the
vallecula lies immediately above and behind the hyoid bone

(Fig. 50)-

Over the free upper border of the epiglottis the mucous
membrane of the mouth becomes continuous with that of the

Tongue

Hyoid
Plica vocalis

Rima glottidi

Recessus piriformis

Superior cornu
of thyreoid

Pharyngeal wall
(cut)

Glosso-epiglottic
fold

Vallecula

Pharyngo-
epiglottic fold

r Epiglottis

Tubercle of
epiglottis

Ary-epiglottic

fold

Laryngeal ventricle

Plica ventricularis
Cuneiform cartilage

Corniculate
'cartilage

Mucous membrane
covering posterior
aspect of cricoid
cartilage

FIG. 48. — Upper Aperture of the Larynx, exposed by cutting through
the posterior wall of the pharynx.

larynx. A fold of mucous membrane stretches from each side
of the epiglottis downwards, backwards, and medially to the
apex of the arytenoid cartilage (ary-epiglottic folds). These
folds, together with the epiglottis, form the boundaries of the
upper opening into the larynx, and owing to the obliquity of its
lateral margins, the plane of the opening looks almost directly
backwards. Between the ary-epiglottic fold and the pharyngo-
epiglottic fold the mucous membrane lines a small depression —
the recessus piriformis — which lies in close relation to the deep
surface of the thyreo-hyoid membrane. This area is supplied

THE NECK 157

by the internal laryngeal nerve, and the lodgment of foreign
bodies in it at once sets up a fit of uncontrollable coughing.
They may be removed by the finger, which is passed backwards
into the mouth close to the dorsum of the tongue, until the epi-
glottis is felt. The recessus piriformis can be explored postero-
lateral to the epiglottis (Fig. 48).

The uppermost part of the larynx is termed the vestibule.
Its cavity narrows from above downwards, and is limited below
by two inwardly projecting ridges on its lateral walls, the ven-
tricular folds (false vocal cords).

The laryngeal ventricle is bounded above by the ventricular
folds, and below by the vocal folds (true vocal cords), which are
separated from one another by the rima glottidis, and lie on a
level with the fifth cervical vertebra. The vocal fold consists
of the ligamentum vocale (p. 155), to the lateral aspect of which
the vocalis muscle is closely applied. Its medial aspect is so
firmly bound down to the mucous membrane that it presents a
whitish colour on laryngoscopic examination. In front, the
vocal fold is attached to the thyreoid angle, and behind, to the
vocal process of the arytenoid cartilage. The intimate relation
of the mucous membrane to the vocal fold is of great importance
in connection with oedema glottidis. Elsewhere in the larynx
the submucous tissue is very lax and distensible. When oedema
occurs in this situation it cannot spread downwards beyond the
vocal folds. In consequence, the laryngeal ventricle may be so
encroached on by the swollen mucous membrane as to hinder
the in-take of air to a serious or even fatal extent.

The-n'wwz glottidis is the narrowest part of the respiratory
tract, and measures i inch antero - posteriorly by J inch
transversely. It corresponds in level to the lower part of the
laryngeal prominence.

On laryngoscopic examination the observer can see the ex-
panded upper end of the epiglottis and the ary-epiglottic folds.
In the posterior part of the latter two elevations can be made
out ; the posterior is produced by the corniculate cartilage (of
Santorini) and the anterior by the cuneiform cartilage (of Wris-
berg), which is a nodule of yellow elastic cartilage embedded in
the fold. Within the boundaries of the aperture both the
ventricular and vocal folds (false and true vocal cords) can be
examined (Fig. 49). The former, which are reddish in colour,
are more widely separated, as a rule, and have only a small range
of movement ; the latter are whitish in colour and move freely

158 THE HEAD AND NECK

during phonation. In quiet respiration the rima glottidis is
triangular with the apex in front, but in forced breathing it
becomes diamond-shaped owing to lateral rotation of the vocal
processes of the arytenoids. During high notes the vocal folds
become adducted, and only the posterior part of the glottis,
i.e. the part between the two arytenoids, remains open. A
yellowish elevation may be observed in the posterior part of
the vocal fold. It is due to the vocal process of the arytenoid.
In addition to the boundaries of the aperture and the interior
of the larynx, a good view may be obtained of the recessus
piriformis and the valleculse, and if the vocal folds are widely
abducted, the interior of the trachea may be examined. It

Base of tongue

Glosso-

epiglottic

fold

Epiglottis
Tubercle-
Plica vocalis

Cuneiform cartilage'

Corniculate cartilage

FIG. 49. — The Larynx as seen in the living subject by means of the
Laryngoscope.

must be remembered that irregular appearances may be caused
by the cicatricial contraction which commonly follows ulceration
in this region.

Polypi and other growths, which may occur in relation to
the epiglottis, ary-epiglottic folds, ventricular and vocal folds,
may be removed via the mouth by the intralaryngeal method.
If this is not possible, satisfactory access may be obtained by
sub-hyoid pharyngotomy (p. 159) or thyreotomy (p. 162).

The lymph vessels of the larynx may be subdivided into a
supraglottic and an infraglottic group. They communicate
freely with one another in the posterior wall of the larynx, but
across the vocal folds the connections are few and irregular.
The supraglottic efferents follow the course of the internal laryn-
geal nerve (p. 159) and open into the upper anterior group of the
deep cervical lymph glands. The infraglottic efferents run

THE NECK 159

downwards in the groove between the trachea and the oeso-
phagus, close to the recurrent nerve, and open into the lower
anterior group of the deep cervical lymph glands. In extrinsic
cancer of the larynx the supraglottic lymphatics are involved,
but in the intrinsic variety the spread occurs along the infra-
glottic vessels.

The upper aperture of the larynx can be brought to the
surface by the operation of Sub-hyoid Pharyngotomy. A
transverse incision is made just below the hyoid bone. This
divides the skin, the superficial fascia, the platysma, and the
deep fascia. The sterno-hyoid, the omo-hyoid, and the thyreo-
hyoid are cut through, but their upper ends are left sufficiently
long to allow them to be sutured subsequently. The thyreo-
hyoid membrane, which is now completely exposed, is incised
horizontally, and in doing so the surgeon is careful not to injure
the internal laryngeal nerve and its accompanying artery (p. 121)
by extending the incision beyond the lateral border of the
thyreo-hyoid muscle.

The internal laryngeal nerve is a branch of the superior laryngeal nerve,
which arises from the vagus a little below the base of the skull. It runs
obliquely downwards, forwards, and medially, deep to both carotid arteries,
and pierces the thyreo-hyoid membrane at the posterior border of the thyreo-
hyoid muscle. It supplies the mucous membrane of the larynx and recessus
piriformis. Section of one internal laryngeal nerve renders the mucous
membrane of that half of the larynx insensitive, but should both nerves be
cut, inhalation pneumonia is likely to supervene owing to the loss of the
cough reflex.

After opening the thyreo-hyoid membrane, the surgeon cuts
upwards and backwards, through the underlying pad of fat,
and divides the ligament which attaches the epiglottis to the
hyoid bone. Above the ligament lie the submucous tissue
and mucous membrane of the valleculae, and when these have
been incised the epiglottis can be pierced by a strong silk ligature
and dragged out through the wound. This proceeding brings
the vestibule of the larynx directly to the surface, and affords
excellent exposure of the area.

Cut Throat. — The commonest sites of the wound in " cut
throat " are immediately above and below the hyoid bone. By
throwing back his head while he makes the wound, the suicide
unconsciously protects the main vessels from danger, as the
action retracts the carotid sheath and its contents more deeply
under cover of the sterno-mastoid. The supra-hyoid incision
cuts through the mylo-hyoids, genio-hyoids, hyo-glossi, and

i6o

THE HEAD AND NECK

Septal cartilage

Perpendicular lamina of ethmoid

Vomer

Splienoidal air sinus

Opening of auditory (Eustachian) tube
Torus tubarius (Eustachian cushion)

Mylo-hyoid -
Investing layer of deep
cervical fascia
Submental lymph gland

Thyreoid cartilage

Lamina of cricoid cartilage

Pretracheal fascia

FIG. 50. — Median Section through Head and Neck. A tuberculous abscess
is depicted, originating in the body of the second cervical vertebra and
descending behind the prevertebral fascia.

THE NECK 161

genio-glossi, and if it begins sufficiently far back it emerges
through the dorsum of the base of the tongue. The lingual
vessels and hypoglossal nerve are divided, but the lingual nerve
usually escapes as it lies above the level of the wound. More
posteriorly, the external maxillary (facial) artery and common
facial vein — which is usually the first large vessel to be severed —
are reached, but the carotid sheath is only injured when the
incision is a very large one.

The infra-hyoid wound closely resembles the incision for
sub-hyoid pharyngotomy (p. 159). Laterally, it cuts through
the superior thyreoid artery and internal laryngeal nerve before
reaching the sterno-mastoid and the carotid sheath. The
epiglottis is apt to be divided, and when it is cut its upper part
may cause respiratory obstruction.

" Cut throat " wounds through or below the thyreoid car-
tilage are by no means common.

The crico-thyreoid muscle arises from the side of the cricoid
cartilage, and passes upwards, backwards, and laterally, to be
attached to the thyreoid cartilage. When the crico-thyreoid
contracts it elevates the anterior part of the cricoid cartilage,
as the thyreoid is held firmly in place by the sterno-thyreoid and
thyreo-hyoid muscles. This movement depresses the posterior
part of the cricoid together with the arytenoids, and thus
separates the posterior from the anterior attachment of the vocal
folds, rendering them tense. The external laryngeal nerve,
which supplies the muscle, is a branch of the superior laryngeal
(p. 159), and lies in close relation to the upper pole of the lateral
lobe of the thyreoid gland. Should the nerve be stimulated by
the pressure of forceps during operations in its neighbourhood,
the resulting muscular response may be so strong as to cause
spasm of the glottis.

The condition of laryngismus stridulus is due to reflex stimu-
lation of the external laryngeal nerve. It may be caused by
direct pressure on the main trunk of the vagus itself from
tuberculous abscesses or enlarged lymph glands in the thorax.
Spasm of the glottis may also occur in gastric disorders, in which
case the afferent impulse travels along the vagus itself, and in
the disturbance due to dentition, when the afferent impulse is
carried up to the sensory nucleus of the trigeminal, from which
it spreads to the motor nucleus of the vagus.

As the two crico-thyreoid muscles diverge from each other
the crico-thyreoid ligament (middle part of crico-thyreoid

11

162 THE HEAD AND NECK

membrane) is exposed in the interval between them. Through
this area the surgeon performs the operation of laryngotomy,
which may be carried out as an emergency operation when
some foreign body lodges in the larynx, or as a preliminary step
in extensive operations on the jaws or mouth. The incision is
vertical as it passes through the superficial structures, but the
actual opening in the ligament is made transversely. In this
way injury to the crico-thyreoid artery is avoided, and the
cartilages can be separated widely to facilitate the introduction
of the laryngotomy tube. Unlike a tracheotomy tube, which is
circular on section, a laryngotomy tube is oval so as to fit accur-
ately into the narrow gap between the cricoid and thyreoid
cartilages. Laryngotomy is not performed in children owing
to the extreme narrowness of the crico-thyreoid ligament.

In the operation of Thyreotomy, or splitting of the thyreoid
cartilage, great care must be exercised to avoid injuring the
vocal folds. The operation is performed through a vertical
median incision, which passes between the depressor muscles of
the hyoid and the anterior jugular veins of the two sides. A
small opening is made in the crico-thyreoid ligament above the
crico-thyreoid artery, and the thyreoid cartilage is split with
scissors. In advanced age, calcification of the cartilage may
render the use of a Gigli saw necessary. It is introduced below,
and passed up through the rima glottidis and brought out through
a second small opening in the thyreo-hyoid membrane.

Laryngectomy. — In excision of the larynx the best approach
is obtained by a median incision, which commences at the hyoid
bone, and is carried downwards beyond the isthmus of the
thyreoid gland. A short transverse incision is made at each end,
and two flaps, consisting of skin, superficial fascia, and platysma,
are turned laterally. The superficial layer of depressor muscles
(p. 154) is divided, and the sterno-thyreoid is cut across low
down. This procedure exposes the thyreoid gland below and
on each side of the larynx. The pretracheal fascia is incised
along the medial border of the upper pole of the gland on each
side, and the isthmus is divided between ligatures. In this
part of the operation the superior thyreoid arteries (p. 167) must
be carefully preserved. The gland can now be separated from
the larynx and the trachea, which is exposed lying on the
anterior surface of the oesophagus. The trachea is separated
from the oesophagus by blunt dissection as high up as the lower
border of the inferior constrictor. The recurrent (laryngeal)

THE NECK 163

nerve and the inferior laryngeal artery pass upwards under cover
of the muscle, and may be divided at this stage. The trachea
is cut through near the cricoid cartilage, and its lower end is
turned forwards and stitched to the lower margin of the skin
incision, since it tends to retract into the thorax.

The larynx is next retracted upwards and forwards, and the
inferior constrictor and the stylo -pharyngeus are divided. In
separating the larynx from the lower part of the pharynx,
care must be taken not to " button-hole " the mucous membrane
on the posterior aspect of the cricoid (p. 189). At the upper
border of the cricoid the pharynx is opened, and the epiglottis
may be cut across if it is not involved. The larynx is now only
fixed above and in front. The thyreo-hyoid muscle and mem-
brane are divided, and the cut is carried backwards through the
subjacent pad of fat till the divided epiglottis is reached. After
division of the internal laryngeal nerve and its accompanying
artery the larynx can be removed. If the epiglottis is involved
in the disease, the latter part of the operation follows the course
of a sub-hyoid pharyngotomy.

The Trachea begins immediately below the cricoid car-
tilage, and ends opposite the lower border of the fourth thoracic
vertebra by dividing into the two bronchi. It is about 4^ inches
long, and its diameter varies from f inch to one inch. The
cervical part of the trachea is 2| inches long, and as it descends
it becomes more deeply placed, so that at the upper border of the
manubrium sterni it lies i| inches from the surface. In children
of from three to five years of age the cervical part of the
trachea is ij inches long and only £ inch wide. These
measurements give some indication of the variations necessary
in the diameters of tracheotomy tubes.

The trachea is freely movable, since it is surrounded by loose
cellular tissue, and when necessary it can be retracted to one or
other side without much difficulty. The isthmus of the thyreoid
gland lies in front of the second, third, and fourth rings of the
trachea, while the lateral lobes lie one on each side in relation
to the upper six rings and to the cricoid and thyreoid cartilages.

The posterior surface of the trachea, which is in contact
with the oesophagus, is flattened so that the tube is horseshoe-
shaped on section. This is due to a deficiency in the cartilagin-
ous rings posteriorly. The posterior wall consists of the mucous
membrane and the fibro-elastic coat of the trachea. If the
surgeon, in performing tracheotomy, opens the trachea too

164 THE HEAD AND NECK

vigorously, he may slit the posterior wall and open into the
subjacent oesophagus.

The operation of High Tracheotomy is performed through
the interval between the cricoid cartilage and the isthmus of the
thyreoid gland. It is usually carried out for some form of
laryngeal obstruction, and has been labelled an " emergency "
operation. There is, however, no necessity for excessive hurry,
because, provided that the patient is not further embarrassed
by the administration of a totally unnecessary anaesthetic,
respiration can always be restarted after the trachea is opened.
During the operation the neck is well extended over a small
sandbag or cushion, and is held in position in the middle line
by an assistant until the tracheotomy tube has been inserted.
In this way the trachea is steadied and drawn tight, for its
rounded shape renders it liable to be pushed aside, especially
if the head is not held absolutely in the middle line, in which
event the oesophagus may be opened by mistake. The incision
may be either vertical or horizontal as it divides the skin and
superficial fascia, but it should pass vertically between the two
anterior jugular veins. On account of the obstruction to
respiration these veins are engorged and may almost touch one
another. The investing layer of the deep fascia is incised vertic-
ally, and if the subjacent sterno-hyoids are close together they
must be retracted. The surgeon now feels for the cricoid
cartilage and the isthmus of the thyreoid gland, and when these
guides have been identified he makes a transverse cut through
the pretracheal fascia just below the cricoid cartilage. The
isthmus of the thyreoid gland, with its fascial sheath derived
from the pretracheal fascia, can now be retracted downwards,
exposing the upper rings of the trachea. A vertical incision is
then made in the exposed part of the trachea from below up-
wards, the back of the knife being directed to the isthmus of the
thyreoid gland to avoid injuring the anastomosing terminal
branches of the superior thyreoid arteries on its upper border.
If sufficient room is not obtained by this method, the cricoid
cartilage may be divided, or the isthmus of the thyreoid gland
may be cut through. It is said (Treves) that there is no danger
of thyreoidism by absorption from the unligated portions of
the gland. When the tube is inserted care must be taken not
to pass it down the outside of the trachea amongst the depressor
muscles nor between the fibro -elastic membrane, in which the
cartilaginous rings are embedded, and the mucous lining.

THE NECK 165

Low Tracheotomy is usually performed to relieve dyspnoea

Digastric,
anterior belly

Thyreo-hyoid

membrane

Thyreoid _
cartilage
Thyreo-hyoid

Stcrno-hyoid

Cr

cart

Anterior
jugular vein

Fascia enclosing
suprasternal space

Pretracheal fascia,
cut to show forma-
tion of sheath of
thyreoid gland

'•*• Sterno-mastoid

Connection between anterior jugular veins

FIG. 51. — The Anterior Median Line of the Neck. On the left side the
platysma has been removed, and the sterno-hyoid and sterno-thyreoid
have been partially resected.

produced by malignant disease of the thyreoid gland. In this

11 a

i66 THE HEAD AND NECK

operation the trachea is opened below the isthmus of the thyreoid
gland, and the wound will necessarily be deep, as this part of
the trachea lies at some distance from the surface. On this
account the skin incision must be a long one, and it should
extend down to the jugular (supra-sternal) notch or on to the
sternum. It is vertical in direction, and passes through Burns's
space (p. in). In the cellular tissue which occupies the space,
the communicating branch between the two anterior jugular
veins must be found (Fig. 51), ligatured, and divided. The
posterior wall of the space is then cut through and a collection
of loose fat is encountered. In this fat, which also contains a
few lymph glands, the inferior thyreoid veins descend in front
of the trachea from the lower and medial surfaces of the lateral
lobes of the thyreoid gland. The veins of the two sides may
unite and join the left innominate vein, or they may open
separately into the right and left innominate veins. When
present, the thyreoidea ima artery ascends in this fat from the
innominate artery to the lower border of the isthmus of the
thyreoid gland. All these vessels may require to be tied before
the pretracheal fascia is divided. The trachea is then incised
from belowr upwards lest any injury be done to the left innominate
vein or the innominate artery, which sometimes occupy a higher
position than usual.

In children low tracheotomy may be rendered very difficult
owing to the shortness of the neck and the presence of the
thymus gland. Further, the position of the innominate artery
and the left innominate vein is slightly higher than in the adult.
The Thymus Gland is of considerable size in the fcetus ;
it undergoes little alteration in size during childhood, but there-
after it undergoes almost complete atrophy. It is enclosed in
a fascial sheath and lies in the superior mediastinum, in front
of the trachea and great vessels, and immediately behind the
manubrium sterni. Recent observations tend to show that in
the infant certain obscure conditions, which are associated with
dyspnoea and stridor, are due to hypertrophy of the thymus
gland, and the operation of subtotal subcapsular thymectomy has
been performed successfully in several cases.

The method of approach is the same as that employed in
low tracheotomy. The gland is found behind the posterior
wall of Burns's space, and one lobe may be shelled out from its
sheath by blunt dissection.

The Thyreoid Gland consists of an isthmus and two lateral

THE NECK 167

lobes. The position and relations of the isthmus are referred
to on p. 163. Each lateral lobe is conical in shape ; the broad
base extends downwards as far as the sixth ring of the trachea,
and the apex passes upwards on to the lamina of the thyreoid
cartilage. The medial surface of the lateral lobe is closely
applied to the trachea and larynx, in front, and to the cesophagus
and pharynx, behind. Postero-laterally the gland is in contact
with the carotid sheath, while its antero-lateral surface lies
under cover of the depressor muscles of the hyoid bone (Fig. 36).
Sometimes an additional lobe — the pyramidal lobe — is present.
It ascends from the upper border of the isthmus on one or other
side of the median plane, and it may be attached to the hyoid
bone by a fibre-muscular slip, termed the levator glandulse
thyreoideae.

The pretracheal fascia invests the gland with & fibrous sheath,
which is thickest on its deep and postero-lateral aspects, and is
very adherent to the trachea behind the isthmus. The gland
can easily be separated from its sheath, save on the posterior
aspect of the isthmus where the two are intimately connected.
In addition to its loose fascial sheath, the gland is provided
with a complete fibrous capsule, which envelops it closely, and
sends in numerous fibrous septa to separate the lobules and acini
from one another. The numerous blood-vessels of the gland
run in the fibrous septa, and are brought into close contact with
the outer aspects of the acini.

The blood-supply of the thyreoid gland is derived from the
superior and inferior thyreoid arteries (pp. 121, 143). The former
is mainly distributed to the medial surface of the upper pole of
the lateral lobe and to the isthmus ; the latter supplies the
lower pole and lateral surface. Both arteries pierce the fascial
sheath posteriorly, and are then associated with the parathyreoid
glands (p. 169).

In the operation of Thyreoidectomy it is advantageous
to have the patient's head, neck, and thorax on a slight upward
incline in order to diminish the haemorrhage. Kocher's collar
incision or the angular incision may be employed, and both give
good access to the gland. The angular incision begins on the
posterior border of the sterno-mastoid at the level of the hyoid
bone, passes downwards and medially to the cricoid cartilage,
and is then carried vertically downwards in the median line to
the jugular (supra-sternal) notch. In the upper part of the wound
the incision is deepened through the superficial fascia and the

116

168 THE HEAD AND NECK

platysma, and, after the external jugular vein has been dealt
with, the flap is undercut and turned downwards and laterally.
The investing layer of the deep cervical fascia is divided vertically
between the anterior jugular veins, which are both secured, and
the depressor muscles of the hyoid are then identified. Some-
times the muscles are spread out in a thin sheet over the tumour,
and the recognition of their edges may offer some difficulty.
The sterno-hyoid and the omo-hyoid are divided high up to
preserve their nerve-supply, and in such a way that they can be
reunited at a later stage. The sterno-thyreoid, which is now
exposed, is carefully raised from the surface of the gland so as
to avoid injuring the superior and the middle thyreoid veins
(p. 119); and it is then cut across. The thyreoid veins are now
doubly ligatured and divided lest they should be torn during
the subsequent manipulations. The incision is deepened in
the median line between the two sterno-thyreoids, and passes
through the pretracheal fascia, which forms the loose fascial
sheath of the gland. The surgeon can now introduce a finger
into the space between the sheath and the true capsule of the
gland. This space is crossed by the thyreoid veins and arteries.
The surgeon next ligatures the superior thyreoid artery within
the sheath, and in this way the external laryngeal nerve, which
is associated with the artery outside the sheath, cannot be
injured. The upper pole of the gland can now be brought up
into the wound, and the isthmus is divided, after it has been
separated from the adhesions which bind it to the sheath. The
tumour is now more movable, and by turning the lateral lobe
forwards and medially, the inferior thyreoid artery may be
secured within the sheath and close to the gland. If the sheath
is left intact postero-medially, the recurrent (laryngeal) nerve,
which crosses the artery in this situation, will not be seen, since
it lies outside the fascial sheath (Fig. 36).

The thyreoid gland normally follows the movements of the
trachea in swallowing, but when it is the site of malignant disease
it becomes adherent to the surrounding structures and fails to
do so. This fixation of the thyreoid gland may also be produced
by syphilitic adhesions following a broken-down gumma.

Simple tumours of the thyreoid gland rarely give rise to any
irritation of the recurrent nerve, but malignant tumours frequently
do so. Both varieties may cause severe dyspnoea by direct
pressure on the trachea. Thyreoid tumours may displace the
carotid sheath and its contents laterally into the posterior

THE NECK 169

triangle, or they may enlarge in a downward direction and
pass through the thoracic inlet (intra-thoracic variety).

Adenomata or solitary cysts of the thyreoid gland may be
removed by enucleation. In this operation the capsule and
the gland substance are incised until the wall of the cyst or
adenoma is reached, and the tumour is then removed by blunt
dissection, together with the thinned-out portions of glandular
tissue and sheath which lie superficial to it.

Loss of the thyreoid secretion during childhood, either from
atrophy or congenital absence of the gland, leads to the condition
of cretinism, while atrophy or complete removal of the gland in
adult life causes myxcedema.

The Parathyreoid Glands are small pea -like structures,
two on each side, which lie normally on the posterior aspect
of the lateral lobes of the thyreoid gland, and are most
commonly found embedded in its fibrous capsule. The
removal of all of these bodies leads to tetany and death.
Consequently, in total removal of the thyreoid gland, which
is only performed for malignant disease, great care is exercised
to leave some of the parathyreoids intact. They can usually
be identified by their close relation to an anastomosing
vessel which connects the superior and inferior thyreoid
arteries on the posterior aspect of the lateral lobe of the
gland.

Development of the Thyreoid Gland. — The thyreoid gland
arises as a median diverticulum of the entoderm of the floor of
the primitive pharynx, and grows tailwards in the interval
behind the tuberculum impar (p. 193). In doing so it passes
ventral to the cartilages of the second to the sixth visceral arches.
At first a hollow bud, the thyreoid rudiment soon becomes solid,
and enlarges to form the isthmus and lateral lobes of the gland.
Its connection with the floor of the mouth, which is termed the
thyreo-glossal duct, gradually disappears, and the foramen caecum
on the dorsum of the tongue is all that normally remains of its
upper end. The pyramidal lobe and the levator glandulse
thyreoidese are derived from its lower end.

Occasionally the thyreo-glossal duct is found embedded in
the hyoid bone. It is probable that in these cases the diver-
ticulum passed behind the cartilage of the second but in front
of the cartilage of the third arch, and was caught between them
when they fused to form the body of the bone (p. 149). Abnormal
remains of the duct may form thyreo-glossal cysts and tumours.

i yo THE HEAD AND NECK

The parathyreoid glands are derived from the entoderm
lining the third and fourth visceral pouches (p. 149).

Thyreo-glossal Cysts or tumours may arise in the lingual
or cervical part of the duct. In the former case they lie between
the genio-glossi (p. 148) ; in the latter they are median, and
lie superficial to the thyreoid or cricoid cartilage. Recurrence
of the condition is certain if any procedure short of complete
excision is attempted. The operation may be one of great diffi-
culty, as it frequently entails a dissection right up to the foramen
caecum. The procedure is similar to that already described for
the removal of a branchial fistula, but it is advisable to resect
the central portion of the hyoid bone lest some of the germinal
cells of the tract are embedded in it (p. 169). Recurrence of
the condition due to neglect of this important detail is now a
well-recognised possibility (Stiles).

THE FACE, MOUTH AND PHARYNX

Bony Landmarks. — At the junction of the intermediate
and medial thirds of the upper margin of the orbit the supra-
orbital notch can be examined, and the supra-orbital nerve,
which it transmits, can be rolled against the bone. The super-
ciliary arch (ridge) lies just above the upper margin of the orbit
and is more prominent medially. In the middle line the two
arches are united by an elevation, the glabella ; it lies a little
above the nasion, a depression at the root of the nose, which
indicates the naso-frontal suture. If the nasal bones are traced
downwards in the median line, their union with the nasal car-
tilages will be recognised by a slight depression, and on each
side of the nose at this level the margins of the apertura piri-
formis (osseous anterior nares) can be felt. The anterior nasal
spine is recognised by placing the finger on the middle of the
upper lip and pressing upwards against the nasal septum.

The zygomatic process of the temporal bone runs forwards
from the tragus to articulate with the zygomatic (malar) bone,
forming the zygomatic arch. Below the anterior part of the arch
the fingers can be inserted into the infra-temporal (zygomatic)
fossa, but the temporal fascia, which is attached to the upper
border of the arch, is so dense that the temporal fossa cannot be
explored in the same way. The tubercle of the zygomatic
(malar) bone is felt when the upper border of the arch is traced

THE FACE, MOUTH AND PHARYNX 171

forwards and upwards, and half an inch above it the zygomatic
process (external angular process) of the frontal bone is en-
countered. The pre-auricular point is situated on the zygomatic
process of the temporal bone immediately in front of the tragus.
Here the superficial temporal vessels can be compressed against
the bone as they cross the zygomatic arch.

Immediately in front of the tragus and below the root of
the zygomatic process of the temporal bone the condyle of the
mandible can be made out, and when the mouth is opened it
slides forwards so that the finger can be inserted into the hollow
of the mandibular fossa. If the finger is placed immediately
below the zygomatic bone the coronoid process impinges on it
when the mouth is opened, and it can be traced downwards into
the anterior border of the ramus of the mandible. The coronoid
process can also be examined from the inside of the mouth, and
the tense band of the ptery go -mandibular raphe (p. 176) is felt
on its medial side. The posterior border of the ramus, though
masked above by the parotid gland, can be felt through the skin,
but its outer surface is completely covered by the masseter.
The angle and outer surface of the body of the mandible are palpable
through their coverings, and with one finger outside and another
inside the mouth it is possible to estimate the thickness of the
bone and to recognise any thickening or irregularity. Near the
lower border of the symphysis, and on its inner aspect, the mental
spine (genial tubercles) may be felt by pressing upwards through
the apex of the submental triangle.

A line drawn from the supra-orbital notch to the lower border
of the mandible so as to pass between the two lower premolars
will cross the infra-orbital foramen a quarter of an inch below
the lower margin of the orbit. It also passes through the mental
foramen, which usually (depending on the age of the subject)
lies midway between the upper and lower borders of the
mandible.

The Skin of the Face possesses numerous sebaceous and
sweat glands, and lies in intimate relationship with the sub-
jacent loose connective tissue, in which the muscles of facial
expression are embedded. The absence of deep fascia from the
face allows muscles arising from bone to be inserted directly
into the skin, which is therefore freely movable. Further, the
laxity of the cellular connective tissue, which is unsupported by
deep fascia, facilitates the rapid spread of oedema over large
areas. Over the nose, however, the skin is firmly bound down

1 72 THE HEAD AND NECK

to the subjacent cartilage, and inflammation in this region is
acutely painful.

Excellent results are obtained from plastic operations on
the face, as the skin can easily be stretched while still in contact
with the underlying connective tissue. This latter is well
supplied with blood-vessels, and hence the vitality of the skin
is not affected.

Cutaneous Nerves.— The whole of the skin of the face, with
the exception of an area over the angle of the mandible, is
supplied by the three divisions of the trigeminal nerve. The
ophthalmic nerve supplies most of the area derived from
the fronto-nasal process (p. 191), the (superior) maxillary nerve
supplies the area derived from the maxillary process, and
the mandibular (inferior maxillary) that from the mandibular
arch.

The supra-trochlear and supra-orbital nerves arise from the
frontal branch of the ophthalmic and leave the orbit at its upper
margin. The former is the more medial, and supplies a small
area of the skin of the forehead. The latter emerges through
the supra-orbital notch, accompanied by the supra-orbital
branch of the ophthalmic artery, and supplies the skin of the
forehead and the front of the scalp. This nerve may require
to be divided in cases of severe neuralgia. An incision is made
through the eyebrow immediately over the notch and is carried
down to the pericranium. In this way the nerve is at once
divided; but, to prevent regeneration, the proximal portion
is found by separating the lower edge of the wound from the
pericranium, and a piece of it is resected as it enters the flap
close to the notch.

The terminal branches of the lacrimal division of the
ophthalmic nerve supply the skin and subjacent conjunctiva
of the lateral part of the upper eyelid.

The terminal branches of the naso-ciliary (nasal) division
of the ophthalmic nerve appear on the face as the infra-trochlear
and external nasal nerves (Fig. 52).

Branches of the infra-orbital nerve, which is the terminal
portion of the maxillary, supply the lower eyelid, the side of
the nose and the cheek adjoining it, and the upper lip. Severe
neuralgia, radiating over the areas indicated, is not uncommon,
and the infra-orbital nerve may be exposed by a horizontal
incision just below the infra-orbital margin and above the fora-
men of the same name. The incision is carried down to the

THE FACE, MOUTH AND PHARYNX

periosteum; and its lower border is separated downwards by blunt
dissection. In this way the nerve is found as it leaves the canal.
If the neuralgia affects the teeth and gums of the maxilla, the
proximal portion of the nerve, after division, must be twisted
out. When this is done the anterior and middle superior

Auriculo-temporal nerve

Supra-orbital nerve

Supra-trochlear
nerve

Lacrimal nerve

Infra-trochlear
nerve

Infra-orbital

nerve
External
nasal nerve

Buccinator nerve
>uccal nerve

Mental nerve

Parotid gland

FIG. 52.— The Nerves of the Face.

alveolar (dental) branches are destroyed, since they arise from
the infra-orbital nerve as it lies in its canal in the floor of the
orbit.

The zygomatico- temporal (temporal) and zygomatico -facial
(malar) are the only other branches of the maxillary nerve which
appear on the face.

Three branches of the mandibular (inferior maxillary)
division of the trigeminal supply cutaneous areas in the face.

174 THE HEAD AND NECK

(i) The buccinator (long buccaT) nerve supplies the posterior part
of the cheek, and (2) the mental nerve, which is the terminal
branch of the inferior alveolar, supplies the skin overlying the
body of the mandible. In severe neuralgia the mental nerve
can be exposed by an incision through the outer side of the gum
just beneath the lower premolars. The lower part of the wound
is retracted downwards, and the nerve is found as it leaves the
mental foramen. When the pain also affects the gums and
teeth the nerve is twisted out in order to destroy, if possible,
the inferior dental plexus within the canal.

(3) The auriculo-temporal nerve supplies the skin in front of
the ear, and extends upwards to the vertex. In addition, it
supplies the skin of the upper part of the auricle and the integu-
ment which lines the external acoustic meatus and covers
the membrana tympani. On this account foreign bodies in
the meatus and chronic inflammatory conditions of its walls
commonly cause referred pain over the side of the head.

The remainder of the auricle and the skin over the angle
of the mandible are supplied by the great auricular nerve (C. 2
and 3).

Congenital cutaneous naevi on the face (" port wine stains ")
map out very accurately the areas supplied by one or more
divisions of the trigeminal.

The External Maxillary (Facial) Artery (p. 122) crosses
the inferior border of the mandible just in front of the masseter
(i£ inches from the angle of the mandible), and its pulse can
readily be felt in that situation. It then runs upwards and
forwards over the bone and the buccinator to a point half an
inch lateral to the angle of the mouth, and from there to a point
a little behind the ala nasi. Thereafter it ascends to the medial
palpebral commissure (inner canthus), where it anastomoses
with the terminal branches of the ophthalmic artery. In this
situation, therefore, there is an anastomosis between the internal
and external carotid arteries. In the lower part of its course
the artery is covered by the platysma and the risorius, which
blend with one another in the lower part of the face. Near the
angle of the mouth it becomes quite superficial, but at a higher
level it is crossed by the zygomaticus and by the muscle which
elevates the upper lip. The course of the vessel is very tortuous,
so that it is not affected by the free movements of facial
expression.

A free anastomosis occurs between the vessels of the two

THE FACE, MOUTH AND PHARYNX 175

sides, and in addition each anastomoses with the transverse
facial and middle temporal branches of the superficial temporal
artery.

The superior and inferior labial (coronary) branches supply
the lips and lie in the submucous tissue. During operations
on the lips, these vessels are controlled by an assistant, who
grasps the lip between his finger and thumb. It should be
remembered that they lie very close to the muco-cutaneous
junction.

The Anterior Facial Vein descends from the medial
palpebral commissure (inner canthus), posterior to the external
maxillary artery, but its course is much straighter than that of
the artery. At its commencement, where it is known as the
angular vein (p. 220), it communicates with the ophthalmic
veins — and therefore indirectly with the cavernous sinus — and
it terminates by uniting with the posterior facial (p. 176) to form
the common facial vein, which joins the internal jugular. If it
is involved in an acute infective process, such as carbuncle,
septic thrombosis with embolism may occur owing to the absence
of valves. The condition may spread in either direction, for
if there is any obstruction to the downward flow, the direction
of the stream is at once reversed. If it spreads upwards it may
cause thrombosis of the cerebral sinuses, but if downwards it
may set free septic emboli into the internal jugular vein. Below
the zygomatic bone and in front of the masseter the anterior
facial vein communicates freely with the pterygoid venous
plexus, and this, in its turn, communicates with the cavernous
sinus through the foramen ovale and the foramen Vesalii.
Infection may reach the cerebral sinuses by this route, either
from the anterior facial vein or from the pterygoid plexus.

The Parotid Gland occupies the interval between the
mastoid process and the posterior border of the ramus of the
mandible, and its deep part rests on the styloid process. It
is limited above by the zygomatic arch and the external acoustic
meatus, and below it overlaps the posterior belly of the digastric..
In front it extends on to the surface of the masseter (Fig. 52).
It is completely enclosed by a fascial sheath derived from the
deep cervical fascia, which sends fibrous septa into the gland.
The superficial portion of the sheath is extremely dense and
strong, and offers great resistance to any swelling of the parotid
or to any enlargement of the lymph glands which lie embedded
within it.

176 THE HEAD AND NECK

Branches of the great auricular nerve ramify over the surface
of the sheath, and the auriculo-temporal nerve pierces it just
below the zygomatic process of the temporal bone. Any acute
or rapidly growing swelling within the sheath will press on these
nerves and give rise to pain, which is referred to the areas of
their distribution. In acute parotitis examples of this pain are
afforded during the activity of the gland at meal-times.

The facial nerve, the external carotid artery, and the posterior
facial (temporo-maxillary) vein are all more or less embedded
in the substance of the gland. The nerve traverses the gland
and crosses the vessels superficially.

The Parotid Duct lies one finger's breadth below the zygo-
matic arch, and, when the teeth are clenched, it may be rolled
up and down against the tense masseter. It emerges from the
forepart of the gland, and runs forwards on the masseter to its
anterior border. It then passes medially, piercing the buccin-
ator to reach the mucous membrane of the cheek. Opposite
the second upper molar tooth the parotid duct opens into the
mouth. Septic infection may travel backwards from the mouth
along the duct and involve the gland itself.

Calculi lodged in the distal portion of the duct may be
removed by slitting up the duct from its opening within the
mouth. A similar route is adopted for opening abscesses in
connection with the buccinator lymph glands. The incision is
made horizontally through the mucous membrane to one side
of the opening of the parotid duct, and both the mucous mem-
brane and the buccinator are cut parallel to the course of the
duct.

The Buccinator arises from the outer alveolar margins of
the maxilla and mandible in the region of the molar teeth, and
its posterior border is attached to the pterygo-mandibular
raphe, which is a fibrous band extending from the hamulus of
the medial pterygoid lamina (plate) to the posterior end of the
mylo-hyoid line of the mandible. Its fibres run horizontally
forwards, and fuse with the orbicularis oris at the angle of the
mouth. Like the muscles of facial expression, it is supplied by
the facial nerve. It forms the muscular stratum of the cheek,
and when it is paralysed portions of food become retained
between the cheek and the gums on the affected side.

The lymph glands of the parotid region are divisible into
two groups; one, the anterior auricular (pre-auricular) , lies super-
ficial to the sheath, while the other, the group of parotid lymph

THE FACE, MOUTH AND PHARYNX 177

glands, is scattered throughout the substance of the gland,
though chiefly situated near its surface. The anterior auricular
lymph glands drain the frontal and temporal regions and receive
some of the deep facial lymph vessels. The parotid lymph
glands drain the upper and posterior part of the naso-pharynx
and the pterygoid lymph glands. Abscesses arising in connec-
tion with the anterior auricular lymph glands point superficially,
but, when they arise in connection with the parotid lymph glands,
they rarely point on the surface, owing to the strength of the
parotid sheath. In these cases the pus may pass upwards and
find its way into the external acoustic meatus, or it may travel
medially and reach the side wall of the nasal pharynx. In the
latter case it ultimately descends along the medial side of the
carotid sheath.

Pus inside the parotid gland is evacuated by Hilton's method,
but the surgeon must be certain of its presence before exploring
the gland. Irreparable damage may be done to the facial
nerve by repeated unsuccessful endeavours to locate pus.

An isolated lymph gland of the parotid group, which lies
near the surface of the salivary gland at about the level of the
tragus, is not uncommonly affected alone. It can be shelled
out through a small horizontal incision, parallel to the facial
nerve. The superficial structures, the sheath of the gland, and
probably some parotid tissue are cut through before it is reached.
Mixed tumours of the parotid (as well as some inflammatory
swellings) sometimes produce slight facial paralysis. Encapsuled
tumours can often be enucleated through a larger incision in
the same region without much damage to the facial nerve,
provided that all cutting is done parallel to its branches (p. 178).

When Eemoval of the whole Parotid Gland for malignant
disease is contemplated, a large curved incision is necessary.
It commences at the mastoid process, and passes down the
anterior border of the sterno-mastoid to a point below the angle
of the mandible, and it is then carried upwards and forwards
on to the face. The flap is turned upwards, and the external
jugular vein and the external carotid artery are secured at once.
The gland is most easily freed from below and then from in front,
after ligature of the parotid duct. In separating the deep
surface of the gland from the muscles attached to the styloid
process, care must be taken lest the internal jugular vein be
injured, as it may be in direct contact with the gland.

The Facial Nerve (pp. 213, 215) leaves the skull at the

12

178 THE HEAD AND NECK

stylo-mastoid foramen and turns forwards, laterally and slightly
downwards. It at once enters the deep surface of the parotid
gland and gradually becomes more superficial. At the level
of the lobule of the ear, one finger's breadth below the zygomatic
arch, the facial nerve may be rolled against the neck of the
mandible, although it is here embedded in the parotid gland.

Temporary facial paralysis may result from bruising of the
nerve by the application of forceps at birth, as the stylo-mastoid
foramen in the infant is placed on the infero-lateral aspect of
the skull and the mastoid process is not yet developed (p. 210).

Immediately after it leaves the skull the facial nerve gives
off its posterior auricular and digastric branches ; the latter
supplies the stylo-hyoid in addition to the posterior belly of the
digastric. Within the parotid gland the nerve at once breaks
up into its main branches, which radiate away from one another
as they leave the gland (Fig. 52). They all terminate by sup-
plying muscles of facial expression.

Incisions ascending from the neck behind the angle of the
mandible must be only skin-deep at the level of the lobule, other-
wise the main trunk of the facial nerve may be divided.
Similarly, incisions on the face should be made parallel to its
branches of distribution ; they should therefore radiate from
the middle of the anterior border of the lobule. In the child,
up to the age of two, the nerve may be divided by incisions
beneath the auricle, such as that employed in mastoiditis (p. 2 15).

Division of the cervical branch of the facial nerve is referred
to on p. 108,

Facio-Hypoglossal Anastomosis is performed for facial
paralysis produced by disease or injury of the nerve in its course
through the facial canal (aqueduct of Fallopius).

The incision, which begins high up on the mastoid process
and runs downwards to the greater cornu of the hyoid bone, is
planned so as to give good exposure of both nerves.

The deep fascia is incised immediately in front of the mastoid
process and the parotid gland is pushed forwards. An aneurism
needle is inserted deeply in the gap thus made, and hooked up
towards the surface. The facial nerve, which is caught by the
needle on a level with the middle point of the lobule of the ear,
is traced to the stylo-mastoid foramen and there divided. In
order to get a sufficiently long segment of the nerve the bone
may require to be chipped away, and the nerve may be traced
for a short distance into the parotid gland.

THE FACE, MOUTH AND PHARYNX

179

The hypoglossal nerve is found in the anterior end of the
wound as it lies in the angular interval between the two bellies
of the digastric (p. 145). The incision is carried down through
the deep fascia till the posterior belly of the digastric and the
submaxillary gland are exposed. This part of the hypoglossal
nerve is chosen by the surgeon because a long segment is required
to minimise any strain on the subsequent anastomosis. Further,
the nerve is easily found in this part of its course, whereas, at a
higher level, it lies more deeply, and its isolation would involve
considerable risk of injury to the internal jugular vein. The
nerve is cut through and withdrawn from under cover of the
posterior belly of the digastric. This necessitates section of the

Upper joint cavity
Discus articularis \
Lower joint cavity \
Capsule \

Tuberculum articulare

Mastoid process

Styloid process

FIG. 53. — Section through the Mandibular Joint.

branch of supply to the thyreo-hyoid and, perhaps, of the ramus
descendens hypoglossi. The proximal extremity of the hypo-
glossal nerve is then turned up over the posterior belly of the
digastric and united to the distal portion of the facial nerve,
which is turned down to meet it.

In similar cases the (spinal) accessory nerve may be united
to the facial. It is found .at the anterior border of the sterno-
mastoid (p. 135).

Temporo-Mandibular Joint. — At this joint the condyle of
the mandible articulates with the mandibular (glenoid) fossa
of the temporal bone, which is limited posteriorly by the tym-
panic plate and in front by the articular tubercle (eminentia
articularis). The capsule, which is loose and so permits of free
movement, is attached to the margins of the cartilage-covered

i8o THE HEAD AND NECK

areas. It gives attachment on its inner surface to the discus
articularis, which divides the joint cavity into an upper and a
lower part. Anteriorly, the capsule is deficient, and the tendon
of the external pterygoid gains insertion into the articular disc.

Laterally, the capsule is strengthened by the temper o-
mandibular (external lateral) ligament, the fibres of which are
directed downwards and backwards to the lower part of the neck
of the condyle. The obliquity of these fibres helps to prevent
the condyle from passing backwards and fracturing the tym-
panic plate, when a blow falls upon the chin.

In the movements of protrusion and retraction of the man-
dible, the condyle and the articular disc move together over the
surface of the mandibular fossa. When the mouth is opened
the articular disc and the condyle both move forwards, but, at
the same time, the condyle rotates around a transverse axis,
which passes through the lower attachment of the temporo-
mandibular (external lateral) ligament. The latter becomes
tense when the mouth is widely opened and the condyle rests
on the summit of the articular tubercle (eminentia articularis).
In this position the mandible can easily be dislocated either by
a blow on the chin or even by the forcible contraction of the
external pterygoids. The method adopted to reduce this dis-
location first depresses the condyle so as to disengage it from
the front of the articular tubercle, and then, by partial closure
of the mouth, the condyle is made to pass back into the man-
dibular fossa. Considerable force is sometimes required to
overcome the spasm of the muscles of mastication.

The spheno-mandibular (internal lateral) ligament is placed
at some distance from the joint and gives it no support. At-
tached above to the spine of the sphenoid, the ligament descends
to gain attachment to the margin of the mandibular foramen.
The internal maxillary artery and the inferior alveolar (dental)
vessels and nerve intervene between the ligament and the ramus
of the mandible.

At the symphysis the mandibLe is strengthened by the
mental protuberance, and, when fractured, it usually gives way
at the margin of this elevation. The fracture passes through
the large canine socket and is usually compound, as the mucous
membrane of the mouth is so firmly attached to the bone that
it is almost always torn. The inferior alveolar (dental) nerve
may be implicated in the callus and cause neuralgic pain, which
niay be referred over the distribution of the buccinator and

THE FACE, MOUTH AND PHARYNX 181

auriculo-temporal nerves. If the nerve is completely paralysed,
the area supplied by its mental branch loses its sensibility,
and when drinking, the patient can only appreciate the glass
with his lips on the uninjured side.

The Temporal Muscle arises from the temporal fossa and descends under
cover of the zygomatic arch, to be inserted into the margins and deep surface
of the coronoid process. The Masseter arises from the zygomatic arch, and
is inserted into the lateral surface of the mandibular ramus. Both muscles
are powerful elevators of the mandible, and are supplied by the mandibular
division of the trigeminal nerve.

The External Pterygoid arises from the skull in the region of the pterygoid
process (plates) of the sphenoid, and passes almost horizontally backwards,
to be inserted into the condyle and the articular disc (p. 180). Its action is
to draw the condyle and the articular disc forwards, thus protruding the
mandible. As it passes backwards it is in contact with the deep surface of
the temporal muscle. The Internal Plerygoid has a similar but deeper origin.
Its fibres run downwards and laterally, as well as backwards, to reach the
internal surface of the angle of the mandible. Both pterygoid muscles are
supplied by the mandibular division of the trigeminal. When the two ptery-
goid muscles of one side act alone, the mandible is twisted over to the opposite
side. This action is seen in lateral chewing movements, and in paralysis of
the mandibular nerve the mandible is permanently pulled over to the same
side as the lesion.

The Internal Maxillary Artery arises from the external
carotid in the parotid gland at the level of the neck of the
mandible. It passes forwards deep to the bone but superficial
to the spheno-mandibular ligament. It may run either super-
ficial or deep to the external pterygoid, and it terminates in the
pterygo-palatine (spheno-maxillary) fossa, where it gives off
the palatine, infra-orbital, and numerous other small branches.
In the earlier part of its course the artery gives off (i) the middle
meningeal, which ascends deep to the external pterygoid, to
enter the skull through the foramen spinosum ; (2) the inferior
alveolar (dental), which enters the mandibular foramen ; and (3)
branches to the surrounding muscles. The corresponding veins
form a plexus round the pterygoid muscles, which communicates
with the cavernous sinus (p. 225) above, the anterior facial
vein in front, and the posterior facial vein (temporo-maxillary)
behind.

Operations on the Mandible.— The periosteum of the
mandible is thick and strong, and can be easily stripped off the
bone. Further, it is able to reform large portions of the bone
after subperiosteal resection, an operation which is employed
with advantage in tuberculous and chronic septic disease of the
body and ramus. A curved incision is made along the posterior
third of the inferior border of the body, round the angle, and

182 THE HEAD AND NECK

up the posterior border of the ramus. The incision, which
must not be carried upwards too far lest the facial nerve be
injured (p. 178), penetrates down to the bone, and the periosteum
may be stripped off along with the masseter laterally and the
internal pterygoid medially, so as to leave the tuberculous bone
exposed. The affected area may then be removed without
opening into the mouth.

In Excision of the Mandible for malignant disease the bone is
removed along with its periosteal covering. The incision begins
at the margin of the lower lip and is carried down in the middle
line to the lower border of the bone, along which it is carried
backwards to the angle. In this part of the incision, the external
maxillary artery and its accompanying vein are cut through
and secured. The incision is then carried upwards along the
posterior border of the ramus to the level of the tragus. It is
only skin-deep above, so that the facial nerve is not injured.
The soft parts are reflected from the lateral aspect of the bone
and the masseter is cut away from its insertion, and the mucous
membrane is divided as it is reflected from the cheek on to the
external aspect of the gum. A Gigli saw is passed upwards,
internal to the bone, through an opening made in the mylo-
hyoid a little to one side of the median plane, and it is brought
out into the mouth through the mucous membrane of its floor.
The mandible is then divided through the socket of the lateral
incisor tooth, and in this way the mental spine (genial elevation),
with its muscular attachments, is left intact. The bone is
next depressed and dragged outwards through the wound, and
the origin of the mylo-hyoid and the mucous membrane on the
inner aspect of the gum are cut through, until the internal ptery-
goid is reached. When the muscle and the spheno-mandibular
(internal lateral) ligament, which lies on its surface, have been
divided, the inferior alveolar artery and nerve are exposed
between them and the ramus. After they have been secured,
the bone may be depressed still further so as to bring the coronoid
process into view. It may be cut across, 01 the temporal muscle
may be detached from its insertion. The mandible is now only
held in position by the external pterygoid and the temporo-
mandibular joint.

If these structures are cut through with the knife, the internal
maxillary artery (p. 181) is in great danger, and it is safer to
twist the condyle away from its attachments.

The Mandibular (Inferior Maxillary) Nerve is a

THE FACE, MOUTH AND PHARYNX 183

branch of the trigeminal, and leaves the skull through the
foramen ovale. It at once breaks up into numerous branches,
which at first lie deep to the external pterygoid and on
the lateral wall of the nasal pharynx.

The nerve may be reached, for the purposes of injection, by
inserting a needle immediately below the zygomatic arch at a
point 2-5 cm. in front of the external acoustic meatus. It is
directed medially and slightly backwards to a depth of 4 cm.,
when the point comes into contact with the nerve (Symington).
Before reaching the nerve, the needle pierces the masseter
muscle and passes through the mandibular (sigmoid) notch,
the temporal and external pterygoid muscles. If the needle
is passed in for more than 4 cm. it pierces the lateral wall of the
nasal pharynx.

Branches. — (i) The Auricula-temporal nerve passes back-
wards into the parotid gland (pp. 174, 211). (2) The Buccinator
(long buccal) pierces the external pterygoid, and frequently the
anterior fibres of the temporal, before it appears in the face (p.
174). (3) The Inferior Alveolar (Dental) nerve runs downwards,
deep to the external but superficial to the internal pterygoid,
and enters the mandibular foramen in company with the artery
of the same name. As it enters the foramen it gives off (4) the
Mylo-hyoid nerve (p. 144). (5) The Lingual nerve lies just anterior
to the inferior alveolar. On the inner surface of the body of
the mandible it lies above the mylo-hyoid line and, opposite the
third molar (p. 184) tooth it is only covered by the mucous
membrane of the mouth. (6) The remaining branches of the
mandibular nerve are all motor and supply the muscles of
mastication, viz. the temporal, the masseter, and the external
and internal pterygoids. Paralysis of this nerve is referred to
on p. 181.

The inferior alveolar and lingual nerves are sometimes
involved in severe neuralgia, which affects the lower teeth and
gums and the tongue. They may be approached (i) through
the skin of the cheek, or (2) from the inside of the mouth.

i. A curved incision is carried down the lower part of the
posterior border of the ramus and forwards along the inferior
border of the mandible. This incision passes down to the bone
at once, and a flap, consisting of all the superficial structures,
including the periosteum, is thrown forwards. The ramus is
then trephined slightly above the last molar tooth, and the
piece of bone is removed, exposing the periosteum on its deep

184 THE HEAD AND NECK

surface. This is cut away, and the two nerves are found lying
on the internal pterygoid muscle.

2. The mucous membrane of the mouth may be divided
upwards and backwards from the level of the last molar tooth of
the mandible along the inner surface of the ramus. The lingual
nerve is found lying in the submucous tissue, and may be traced
backwards between the ramus and the internal pterygoid muscle
until the lingula of the mandibular foramen can be felt. The
inferior alveolar nerve and vessels are found as they enter the
mandibular foramen a little posterior to the lingual nerve.

This operation is carried out when the patient is anxious to
avoid a skin incision and the subsequent scar.

Dentition. — The first of the deciduous teeth to appear are the lower
central incisors, and they are usually cut between the sixth and eighth months.
The lateral incisors soon follow, and by the end of the year the first deciduous
molars should be visible. Early in the second year the canine teeth erupt,
and the temporary set is completed by the appearance of the second deciduous
molar about the commencement of the third year. The lower teeth usually
appear somewhat in advance of the upper.

The first lower molars are the first of the permanent teeth to erupt, and
should be present by the end of the seventh year. They are followed during
the next two years by the central and lateral incisors. Within the next four
years the first and second premolars, the canines, and the second molars
appear in that order, but the eruption of the last-named is often delayed till
the fifteenth or sixteenth year. The permanent set is completed by the erup-
tion of the third molars, which may appear at any time between eighteen
and thirty.

Irregular dentition is common in rickets, and the upper permanent in-
cisors are sometimes notched. The notching corresponds to a small segment
of a large circle, and has to be distinguished from the notching of the same
teeth in congenital syphilis (Hutchinson* s Teeth), which corresponds to a large
segment of a small circle.

The developing tooth is enclosed in a membranous sac, which, under
normal conditions, atrophies as the tooth increases in size. Occasionally,
however, the sac fails to atrophy, and develops into a dentigerous cyst, which
expands the bone. The cyst usually projects more to the lateral than to
the medial side, and contains the undeveloped tooth attached to its wall.

Alveolar Abscess. — The roots of the teeth are firmly fixed
in their sockets by a highly vascular fibrous membrane, the
alveola -dental periosteum. In peri-odontitis this membrane
swells up and becomes very sensitive. It tends to extrude the
tooth slightly from its socket, so that biting is rendered a painful
process. When an alveolar abscess forms, the pus may make
its way out around the neck of the tooth or burrow through the
alveolus, giving rise to a " gumboil." In the maxilla it may
penetrate the bone laterally and appear near the reflection of
the mucous membrane from the gum to the cheek, or it may

THE FACE, MOUTH AND PHARYNX

pass medially, stripping up the muco-periosteum, and form an
abscess on the palate (Fig. 54). Alveolar abscess in connection
with the teeth of the mandible has been described on p. 145.

The Tongue is subdivided into a pharyngeal and an oral
portion by the sulcus terminalis, a V-shaped groove situated at

Maxilla _
Tooth abscess --
Muco-periosteum of palate —
Tone ue -

Periosteum
Tooth abscess

Maxillary sinus
Inferior meatus

Alveolar abscess
Maxilla

Mucous mem-
brane of cheek

•Submaxilkry duct

'Lingual nerve
Genio-glossus
Sublingual gland

Genio-hyoid

Skin

Digastric, ant. belly j 7

Lymph gland /

Deep cervical fascia

Abcess

Mylo-hyoid
Hyoid bone

FIG. 54. — Frontal Section through the Mouth. Four varieties of alveolar
abscess are shown. In the maxilla, on the right side, the pus has spread
laterally, forming an abscess under the mucous membrane ; on the left
side, it has spread medially, forming a palatal abscess. In the mandible,
on the right side, the pus has perforated the bone medial to the attach-
ment of the deep cervical fascia, forming an abscess which is covered by
the fascia and the skin ; on the left side, the pus has perforated the bone
outside the deep fascia, forming an abscess immediately under the skin.

the junction of its middle and posterior thirds. The apex of
the V lies posteriorly and coincides with the foramen caecum
(p. 169). Numerous collections of lymphoid tissue are present
in the pharyngeal portion of the tongue (Lingual tonsils}. They
form small rounded elevations, and each possesses a crypt into
which mucous glands open.

The mucous membrane on the upper surface of the anterior
two-thirds of the tongue is roughened by the projection of
numerous papillae, but on the under surface it is smooth, and

186 THE HEAD AND NECK

the profunda veins (ranine) can be seen shining through it.
Near the tip of the tongue, and embedded in the muscles on its
under surface, there is a collection of mucous and serous glands,
which occasionally give rise to small cysts. The under surface
of the tongue is attached to the floor of the mouth by a fold of
mucous membrane, termed thefrenulum, which may sometimes
be so short as to interfere with the free movement of the organ
(" tongue tie ").

The submaxillary (Wharton's) duct opens on a small papilla,
which is placed lateral to the point where the frenulum of the
tongue joins the mucous membrane of the floor of the mouth.
The plica sublingualis, which overlies the sublingual gland and
is pierced by its ducts, runs backwards and laterally from the
papilla.

The tongue is plentifully supplied with lymph vessels, from
which arise the large collecting trunks, viz. (i) apical, (2) mar-
ginal, (3) basal, (4) central.

(i) The Apical Lymph Vessels drain the tip of the tongue
and open into the submental lymph glands. Some, however,
pass directly to join the lower anterior group of the deep cervical
lymph glands at the level of the sixth cervical vertebra, and in
consequence these glands may be involved at a very early stage
in malignant disease of the tongue. (2) The Marginal Lymph
Vessels drain the lateral borders of the tongue. Some of them
join the submaxillary lymph glands, but the remainder run
backwards and downwards to open into the deep cervical lymph
glands, which lie on the carotid sheath opposite the third, fourth,
and fifth cervical vertebrae. (3) The Basal Lymph Vessels
drain the dorsum of the tongue. After running backwards
towards the lower pole of the palatine tonsil, they pierce the
superior constrictor, and open into the upper anterior group of
the deep cervical lymph glands under cover of the posterior
belly of the digastric. They communicate very freely with the
corresponding vessels of the opposite side, a point of great
importance clinically. (4) The Central Lymph Vessels drain
the substance of the tongue and descend between the genio-
glossi, to terminate in the lower anterior group of the deep
cervical lymph glands.

Recurrence of malignant disease of the tongue usually mani-
fests itself in the lymph glands and not in the mouth. In
excision of the tongue for malignant disease it is of the greatest
importance to remove all the lymph glands which drain the area

THE FACE, MOUTH AND PHARYNX 187

involved, i.e. not only the proximal glands but also the whole
chain of the deep cervical lymph glands.

On this account Butlin advocated the complete dissection of
the anterior triangle as a routine measure. The area is exposed
by two incisions, one along the whole length of the anterior
border of the sterno-mastoid and the other extending from the
symphysis menti to meet the first at the level of the upper
border of the thyreoid cartilage. The two skin flaps are retracted
and the exposed platysma is removed, since it is traversed by
lymph vessels which connect the deep and superficial cervical
lymph glands. For the same reason the investing layer of the
deep fascia and the pretracheal fascia are both removed, as well
as the stylo-mandibular ligament. All the anterior deep cervical
lymph glands are taken away, and the lower part of the parotid
salivary gland is removed in order to give access to the uppermost
members of the group. In order to make certain that none of
the submaxillary lymph glands are overlooked, the submaxillary
salivary gland is also excised. Finally, after the removal of the
submental lymph glands, the median raphe of the mylo-hyoids
is cut through, and a search is made between the two genio-hyoid
muscles.

When this operation is carried out as a preliminary step to
removal of the tongue, and where there is extensive glandular
infection, the external carotid artery and internal jugular vein
may be resected.

On account of its rich network of lymphatics, and the presence
in its substance of a quantity of loose connective tissue, the
tongue may, in acute glossitis, suddenly become so enormously
swollen as to fill up the mouth and protrude from it. Relief
may be obtained by free incisions, which are made parallel to
the course of the profunda linguae (ranine) artery (i.e. from
behind forwards). In the event of injury to the vessel, which
lies on a deep plane, the haemorrhage may be controlled by
introducing the finger into the mouth and hooking the base of
the tongue forwards against the mandible.

The position of lingual dermoids is described on p. 152.

Removal of One Half of the Tongue for malignant disease
may be performed entirely through the mouth. The mucous
membrane is cut through from the frenulum linguae to the
glosso-palatine arch (anterior pillar of the fauces), along the
line of its reflection from the gum. A second incision is made,
commencing at the frenulum, passing over the under surface of

i88 THE HEAD AND NECK

the tongue, and backwards on the dorsum in the median plane
for some distance beyond the disease. The tongue is next drawn
forwards from the mouth and split in the median plane. The
two incisions in the mucous membrane are united by a transverse
cut, and the stylo-glossus is exposed and divided as it enters
the postero-lateral aspect of the tongue. The genio-glossus and
the hyo-glossus are cut away from their attachments to the
hyoid bone, and at this stage the lingual artery (p. 154) is secured.
In the removal of the whole tongue by the oral route, it is
advantageous to split the organ and take it away in two pieces.

The Palatine (Faucial) Tonsil lies in the lower part of
a triangular depression, the tonsillar sinus, on the lateral wall
of the pharynx. The sinus is bounded in front and behind by
the palatine arches (pillars of the fauces), which meet above
on. the posterior border of the soft palate. The supra-tonsillar
fossa is a small depression which is situated above the tonsil in
the upper part of the tonsillar sinus. Peri-tonsillar abscess
gives rise to a swelling, which may involve the adjoining part of
the palate as well as the supra-tonsillar fossa. It should be
incised with a guarded knife, and the pus evacuated by Hilton's
method. The incision is made at the point where the horizontal
line corresponding to the free border of the soft palate meets
the vertical line corresponding to the glosso- palatine arch
(anterior pillar of the fauces).

Development. — The palatine tonsil does not begin to develop
till the fourth month of foetal life, although the tonsillar
sinus, which represents a persistent part of the second visceral
pouch, appears at a much earlier date. Epithelial buds, which
subsequently become the tonsillar crypts, grow out from the
mucous membrane on the lateral pharyngeal wall into the sur-
rounding mesoderm. The latter becomes converted into
lymphoid tissue which forms the greater part of the tonsil.
Its growth in a lateral direction is obstructed by the pharyngeal
aponeurosis, and so, as the organ grows, it bulges into the oral
part of the pharynx. The tonsil, therefore, consists partly of
mucous membrane, which covers its medial surface and lines its
crypts, and partly of lymphoid tissue.

The deep surface of the tonsil has no definite capsule, and
is only separated from the pharyngeal aponeurosis, which lines
the superior constrictor, by loosely arranged areolar tissue.
On this account the tonsil can readily be dragged medially from
its fossa in the operation of enucleation. Hypertrophy of the

THE FACE, MOUTH AND PHARYNX 189

lymphoid tissue of the tonsil is extremely common in childhood
and youth. The organ may enlarge upwards, downwards, or
medially, and may possess either a sessile or a narrow base.

Modern methods of enucleation of the tonsil endeavour to
remove the whole organ, and sometimes the operation is so
complete that the pharyngeal aponeurosis is in part taken away
and the superior constrictor muscle is exposed.

The blood-supply of the tonsil is obtained from the external
maxillary (facial) through its ascending palatine and tonsillar
branches, from the external carotid through the ascending
pharyngeal artery, and from the lingual through its dorsales
linguae branches. Severe haemorrhage sometimes occurs after
enucleation, and it has been attributed (Merkel) to injury of
the external maxillary artery. This vessel, however, can only
be injured when the muscular wall of the pharynx has been
wounded.

If the operation is performed soon after an attack of acute
tonsillitis, the tonsillar arteries are so much enlarged that they
may give rise to a haemorrhage so profuse as to suggest injury
of some larger vessel.

The lymph vessels of the palatine tonsil join the upper anterior
group of the deep cervical lymph glands. Certain members of
this group (p. 133) rapidly become affected in acute tonsillitis,
and in malignant disease of the palatine tonsil the glandular
enlargement attracts the patient's attention before the throat
condition gives rise to any marked symptoms.

The Pharynx is situated behind the nasal fossae, the mouth,
and the larynx. Above, it is roofed in by the base of the skull,
and below, it becomes continuous with the oesophagus opposite
the sixth cervical vertebra. Its lateral and posterior walls are
supported by the constrictor muscles (p. 190), which are covered
externally by the bucco-pharyngeal fascia. Its anterior wall
is interrupted by the choanae (posterior nares), the isthmus
faucium, and the upper laryngeal aperture (Fig. 50). Below
the last-named it is only separated from the muscles on the
posterior surfaces of the cricoid and arytenoid cartilages by the
mucous membrane.

The Nasal Pharynx is bounded below by the soft palate,
and it can be examined by the finger, introduced through the
mouth, and carried upwards behind that structure. On its
anterior wall the posterior border of the nasal septum (p. 194)
can be felt, and on either side of it the finger can be passed

190 THE HEAD AND NECK

through the choanae so as to touch the posterior extremities of
the inferior and middle conchse (turbinated bones). In the
adult the choanse (posterior nares) measure one inch long and
half an inch wide, but in the child the relative width is much
greater. In the roof the basilar portion of the occipital bone
can be felt, and half an inch below, on the posterior wall, the
anterior arch of the atlas can be recognised. The pharyngeal
tonsil is situated on the posterior wall, and in children a pro-
liferation of its lymphoid tissue (adenoids) may fill up the naso-
pharynx and render nasal breathing impossible. On the lateral
wall the orifice of the auditory (Eustachian) tube leads back-
wards, laterally, and upwards to the tympanum (Fig. 50). The
posterior lip of the opening forms a prominent elevation — the
tubal projection (Eustachian cushion) — due to the cartilaginous
wall of the tube, and behind it lies the pharyngeal recess (of
Rosenmuller). When the orifice of the tube is occluded, e.g.
in adenoids, the air in the tympanic cavity gradually becomes
absorbed and deafness results. Inflation of the tympanum may
be carried out through the pharyngeal orifice of the tube by
means of a Eustachian catheter. The instrument is passed
backwards along the floor of the inferior meatus until the down-
turned point reaches the posterior wall of the nasal pharynx.
The catheter is then rotated laterally through one right angle,
and in this way its point is lodged in the pharyngeal recess. It
is then slowly withdrawn from the nose till the point is felt to
catch on the tubal projection. Slight upward rotation of the
point at this stage, accompanied by partial withdrawal, conducts
it past the obstruction, and if it is now directed laterally again,
the instrument passes into the orifice of the auditory tube.

The lymph vessels of this region join the retro-pharyngeal
lymph glands (p. 114) and the upper posterior group of the deep
cervical lymph glands.

The Superior Constrictor Muscle arises mainly from the pterygo-mandibular
raphe, and is on the same plane as the buccinator (p. 176). Its upper fibres
are inserted into a tubercle on the under surface of the basilar part of the
occipital bone, while the rest of the muscle is inserted into a median raphe
posteriorly. The Middle Constrictor Muscle, which overlaps the lower part of
the insertion of the superior constrictor, arises from the cornua of the hyoid
bone, and its fibres spread out as they pass backwards to the median raphe.
The Inferior Constrictor arises from the sides of the thyreoid and cricoid
cartilages. The lower fibres blend with the muscular wall of the oesophagus,
and the upper fibres overlap the lower portion of the middle constrictor.

The constrictor muscles are supplied by the pharyngeal plexus, which
is formed on the lateral aspect of the middle constrictor by the union! of
the pharyngeal branches of the vagus and glosso-pharyngeal nerves, with

THE FACE, MOUTH AND PHARYNX

191

branches from the sympathetic trunk. The sensory portion of the plexus is
distributed to the whole of the pharyngeal mucous membrane, except that
covering the roof and the adjoining areas of the lateral walls, which is
supplied by a branch from the spheno-palatine ganglion (p. 233).

The Oral and Laryngeal Portions of the Pharynx lie behind
the mouth, the dorsum of the tongue, and the larynx. Later-
ally they are related to the great vessels of the neck, and pos-
teriorly they are separated from the bodies of the upper cervical
vertebrae by the retro-pharyngeal and prevertebral layers of
fascia and the longus colli muscles. A retro-pharyngeal abscess
(p. 114) produces a swelling of the posterior pharyngeal wall
which may obstruct the passage of air during respiration, causing
symptoms not unlike those associated with adenoids and hyper-
trophied palatine tonsils (Fig. 37).

Prosencephalon

Median nasal
process

Eye
Stomatod?eum

Globular process

Olfactory pit

FIG. 55. — The Development of the Face.

Development of the Face and Mouth. — About the thirteenth
day a depression appears on the ventral surface of the embryo
just behind the anterior cerebral vesicle. This is the stomodceum
or primitive mouth, and it is separated from the foregut by the
bucco-pharyngeal membrane, which soon breaks down. An
elevation appears in the middle line of the roof of the stomodceum
— the fronto-nasal process — and the olfactory pits lie on each side
of it. These pits form shallow grooves running backwards in
the roof of the primitive mouth, and they become bounded in
front by elevations produced by the lateral and median nasal
processes, both of which are derived from the fronto-nasal
process. The mandibular arches (p. 148) unite to complete the

192

THE HEAD AND NECK

floor of the stomodceum. From the dorsal part of the man-
dibular arch the maxillary process grows forwards, but above
and behind it is separated from the lateral nasal process by the
naso-maxillary fissure,, a part of which subsequently forms the
orbit (Fig. 55).

These processes fuse so that the median nasal process gives
rise to the nasal septum, the os incisivum (premaxilla), and the
philtrum (middle third) of the upper lip. The lateral nasal pro-
cesses form the roof and sides of the nose, while the maxillary
processes form the cheeks and the remainder of the upper lip.
At a later date the palatal processes grow medially from the
maxillary processes, and unite with the remains of the median

Nasal septum

Inferior conch;

Anterior cranial fossa

Crystalline lem
of the eyeball

alatine process
ental lamina

Man
Meckel's cart

Dental lamina

FIG. 56. — Frontal Section through the Face ol a Human Embryo
at the Seventh Week.

nasal process and with one another. Fusion occurs anteriorly
at first and then spreads backwards.

Prior to their fusion, the lateral nasal and maxillary pro-
cesses are separated from one another by a groove which extends
from the region of the orbit to the olfactory pit. This groove
becomes converted into the naso-lacrimal (nasal) duct, but if
the fusion of the lateral nasal and maxillary processes is incom-
plete, the duct opens out on the surface of the face, a rare
condition, known as colobomafacialis.

The conditions of Harelip and Cleft Palate are brought
about by two or more of the above-mentioned processes failing

THE FACE, MOUTH AND PHARYNX 193

to unite with one another. In the simplest variety, the maxillary
process of one side fails to unite with the mesial nasal process
on the surface only, giving rise to unilateral harelip. When the
failure is more pronounced, a gap exists between the maxilla
and the premaxilla in addition to the harelip. In cleft palate
the palatal processes have failed to unite with one another or
with the nasal septum. As the fusion occurs latest posteriorly,
the bifid uvula is the simplest variety of this defect. The less
complete the fusion, the further forward does the cleft extend.
Thus the palatal processes may unite with the mesial nasal
process but not with one another, in which case the cleft is
confined to the soft palate. A greater degree of deformity is
seen when, in addition to failure of the palatal processes to unite
posteriorly, one palatal process has failed to fuse with the nasal
septum. In this case the floor of the nasal fossa on one side is
wanting, and the fossa communicates with the mouth. Double
cleft palate is the highest degree of this deformity. It is found
when the palatal processes fail to unite with one another pos-
teriorly and both fail to unite with the median nasal process
(i.e. nasal septum and premaxilla). The os incisivum (pre-
maxilla) separates the two clefts anteriorly and renders the
complete cleft Y-shaped. In these cases double harelip is usually
present also, and the clefts extend from the surface to the
tip of the uvula. In making the relief incision in the operation
for cleft palate, care must be taken not to cut too far postero-
medially, lest the palatine artery, which enters the posterior
part of the muco-periosteal flap, be injured.

In making a prognosis with regard to the after-results of
closure of a cleft palate, the shape of the arch must be taken
into consideration, as the flaps are subjected to less tension when
the palatal arch is pointed than when the arch is flat. The
degree of tension may be diminished by fracturing the pterygoid
hamulus (hamular process) (Stiles). By this means the tensor
veli palatini (tensor palati), which winds round the bony process,
is thrown out of action.

Development of the Tongue. — Soon after the appearance
of the branchial arches (p. 148), a small elevation, the tuber culum
impar, appears in the floor of the primitive mouth. Two lateral
swellings arise in connection with the mandibular arches and
surround and fuse with the tuberculum impar. In this way
the anterior two thirds (or oral portion) of the tongue are formed.
About the same time a transverse ridge appears behind the

13

194 THE HEAD AND NECK

tuberculum impar in the region of the third arch. From this
the posterior third (or pharyngeal portion) of the tongue is
developed; and it soon unites with the rest of the organ. The
sensory nerve-supply of the tongue indicates the complexity of
its origin.

The anterior two-thirds are supplied with ordinary sensation
by the lingual and with special sense (taste) by the chorda tym-
pani, i.e. by branches from the nerves of the first two arches.
The posterior third is supplied by the nerve of the third arch,
viz. the glosso-pharyngeal.

The Nose and Air Sinuses. — The development of the
nose has already been outlined on p. 191 . The lateral wall of the
nasal cavity bears the three conchce (turbinated bones), which
project medially and downwards so as to separate the three
meatuses of the nose. The mucous membrane on the lateral wall
is provided with a freely distensible submucous layer, so that
such conditions as hypertrophic rhinitis can readily occur. Over
the septum, which forms the medial wall of the cavity, the
mucous membrane is firmly bound down. The nerves of
ordinary sensation are all derived from the spheno-palatine
(Meckel's) ganglion, except the nasal branch, from the ophthal-
mic, which ramifies on the septum. The olfactory nerves are
distributed to the mucous membrane in the upper third of the
cavity.

Into the forepart of the Inferior Meatus the naso-lacrimal
duct opens under cover of the inferior concha. The Middle
Meatus receives the openings of the infundibulum from the
frontal air sinus, the anterior and middle ethmoidal cells, and the
maxillary sinus (antrum of Highmore) (Fig. 57). The two
former open into the hiatus semilunaris, a curved depression on
the lateral wall. The bulla ethmoidalis, which forms a part of
the ethmoid bone, projects into the middle meatus immediately
above the hiatus. It contains the middle ethmoidal cells,
which open at its upper border. The Superior Meatus receives
the posterior ethmoidal air-cells ; the sphenoidal air-cells open
into a small depression lying above and behind the superior
concha, termed the recessus spheno-ethmoidalis.

The Nasal Septum is formed posteriorly by the vomer,
antero-superiorly by the perpendicular plate of the ethmoid,
and antero-inferiorly by the septal cartilage. Deviation of the
Septum rarely occurs before the seventh year. It may involve
the cartilage only, or both bones and cartilage may be deviated

THE FACE, MOUTH AND PHARYNX 195

to one or other side. It may be caused by excessive growth of
the vomer and the perpendicular plate of the ethmoid, and
the septum buckles along the line of their articulation. Over-
growth of the septal cartilage alone is obstructed posteriorly
by the osseous septum, in which its margins are firmly fixed. In
this case, too, deviation occurs, but only the cartilaginous part
of the septum is affected. Deviation of the septum may result
from trauma, and it tends to occlude the nasal fossa into which
it projects.

Fracture of the nasal bone occurs about half an inch above its
lower margin and usually leads to lateral displacement of the
nose ; but if, in addition, the perpendicular plate of the ethmoid
is broken, the nose is depressed backwards. These fractures
are usually compound through the mucous membrane, and
surgical emphysema is apt to follow if the patient blows his
nose. Owing to the plentiful blood-supply of the parts, rapid
union occurs, and it is therefore important that the fragments
should be replaced as soon as possible after the accident.

The Maxillary Sinus (Antrum of Highmore) appears during
the third month of foetal life as a budding-out from the mucous
membrane of the nasal cavity in the region of the middle meatus.
It grows into the maxillary process, and the maxillary bone is
formed around it.

The maxillary sinus is roughly pyramidal in shape. Its
apex is situated at the zygomatic (malar) process, and its base
forms the lateral wall of the nasal cavity. Above, it is roofed
in by the orbital surface of the maxilla, which is channelled by
the infra-orbital nerve. The postero-lateral wall of the sinus
forms one of the boundaries of the infia-temporal (zygomatic)
fossa, and its antero-lateral wall is depressed externally to form
the canine fossa. Inferiorly, the sinus is bounded by the alveolar
border, and the roots of the molar and premolar teeth form
projections in its floor. The walls are lined by muco-periosteum,
which is continuous with the mucous membrane of the middle
meatus of the nose through the opening of the sinus, which is
placed in the upper part of its medial wall.

Infection may reach the maxillary sinus directly from the
middle meatus, or it may ascend through the floor from carious
teeth. When pus is present in the sinus, the natural method
of drainage into the middle meatus is far from efficient, as the
sinus can only be emptied completely when the head is bent over
to the opposite side. When the patient lies down, the pus

196 THE HEAD AND NECK

trickles down the middle meatus and passes into the naso-
pharynx. Assistance in the diagnosis is obtained by the use of

FIG. 57. — Radiogram of Skull, showing normal Maxillary and
Frontal Sinuses.

transillumination and radiograms. In both, the diseased sinus
is more opaque than the healthy one (Fig. 58).

The sinus may be approached for the purpose of drainage in
three ways : (a) The tooth at fault may be extracted and a hole

THE FACE, MOUTH AND PHARYNX 197

may be drilled upwards through its socket into the sinus, (b)
The lateral wall of the inferior meatus of the nose may b
down and the sinus opened into through its base, (c) The upper
lip may be everted and the muco-periosteum incised over t

FIG. 58. — Empyaema of Maxillary Sinus.

canine fossa. A hole is then drilled through the bone, lateral
to the ridge produced by the root of the canine tooth,
drill were applied to the medial side of the ridge, the inferior
meatus of the nose would be opened into instead of the sinus.
Malignant tumours arising from the muco-periosteal lining
of the maxillary sinus are not uncommon, and the symptoms to
which they give rise depend on the direction in which they grow.

198 THE HEAD AND NECK

If the roof of the sinus is pushed upwards, the eye becomes
more prominent, and neuralgia may occur from pressure on the
infra-orbital nerve. The pain in this case may be referred over
the whole distribution of the trigeminal. If the pressure is
mainly exerted on the medial wall, the naso-lacrimal duct
is obstructed, causing epiphora. As the tumour grows, it
pushes its way into the nasal fossa and blocks that side of the
nose. Forward growth obliterates the canine fossa, and down-
ward growth invades the palate and gives rise to a swelling in
the roof of the mouth. Owing to the depth of the infra-temporal
fossa, backward growth may go on for some time before the
presence of a tumour is suspected.

Eradication of malignant disease in this region necessitates
the removal of the whole maxilla. The reader should follow
on the skull the description given below, as it is important
that the method of approach should be clearly understood,
since it may also be employed for removal of naso-pharyngeal
fibro -sarcomata.

Preliminary laryngotomy and temporary occlusion of the
external carotid artery materially assist the surgeon in perform-
ing this operation.

The incision begins just below the medial palpebral (internal
tarsal) ligament, which can be felt quite distinctly at the medial
angle of the eye, when the lateral palpebral commissure (external
canthus) is drawn laterally. It passes down the side of the nose,
round the ala nasi, and down through the upper lip into the
mouth in the median line. The horizontal part of the incision
runs along the lower margin of the orbit to the zygomatic bone,
and is kept parallel to the branches of the facial nerve (p. 178).
If the external .carotid has not been occluded, the cut branches
of the external maxillary artery bleed profusely, as the incision
is at once carried right down to the periosteum. The flap is
rapidly elevated from the maxilla, and the reflection of the
mucous membrane from the gum to the cheek is divided, so that
the flap may be turned down, kinking the external maxillary
artery, and thus arresting the haemorrhage. In elevating the
flap, the orbicularis oculi, the zygomaticus, and several other
facial muscles are cut through, and the infra-orbital nerve and
its artery are divided as they leave the foramen.

In the next step, the periosteum is elevated from the orbital
surface of the maxilla. It must be preserved, because it sub-
sequently forms a support for .the eye, and because it will prevent

THE FACE, MOUTH AND PHARYNX 199

any possible sepsis from entering the orbit. Further, in this
way the origin of the inferior oblique muscle of the eye can be
preserved intact. The periosteum is elevated over the floor
of the orbit until the inferior orbital (spheno-maxillary) fissure
is reached. A Gigli saw is passed down into the fissure and
brought out again below the zygomatic bone, and the maxilla
is then divided.

The attachment of the lateral nasal cartilage to the frontal
(nasal) process of the maxilla is divided, and the nose can then
be displaced to the opposite side. One blade of a pair of large
bone forceps is passed backwards into the upper part of the nasal
cavity, and the other blade into the orbit towards the medial
end of the inferior orbital fissure. When the blades are ap-
proximated, the frontal process of the maxilla, the lacrimal
bone, and the ethmoidal labyrinth (lateral mass) are divided,
and the naso-lacrimal duct is torn through. To detach the bone
from its attachments posteriorly, the flap must be well retracted,
so that a chisel may be inserted into the groove between the
maxilla and the pterygoid process (plates) of the sphenoid. A
slight blow will effect the separation. The maxilla is still held
in place by the hard palate, which has yet to be divided. The
mucous membrane is cut through from the original incision in
the lip backwards across the gum and along the inner border
of the alveolus, and it is continued round the last molar tooth
to join the incision along which it was previously split between
the cheek and the gum. The palatal aponeurosis and the velum
palatinum (soft palate) are freed from the posterior margin of
the hard palate, and a saw is passed through the anterior nares
and made to cut downwards into the mouth. The maxilla
may now be lifted out with the finger and thumb, as it is
only attached to a few fibres of the internal pterygoid and
the proximal part of the infra -orbital nerve. At this stage
severe haemorrhage will occur from the alveolar (dental)
branches of the internal maxillary artery if the preliminary
step of temporary occlusion of the external carotid has not
been adopted.

The Zygomatic (Malar) Bone may be fractured by direct
violence and depressed inwards. It may be levered back into
position by a strong periosteum detacher, passed upwards
through an incision in the mucous membrane along the line
of its reflection from the cheek to the gum. This fracture may
be associated with fracture of the maxilla, in which case the

200 THE HEAD AND NECK

maxillary sinus is opened into, and there is danger of surgical
emphysema occurring, unless the patient is warned not to blow
his nose.

The Frontal Air Sinus arises soon after birth as an out-
growth of the mucous membrane lining the middle meatus of
the nose, but it does not begin to enlarge until the seventh year.
It grows upwards and backwards, and penetrates into the antero-
medial portion of the orbital part of the frontal bone. The
two sinuses are separated from one another by a thin septum,
which, although median below, is usually deflected to one or
other side above. According to Logan Turner the average
dimensions of the frontal sinus are : Height, from the fronto-
maxillary suture upwards, i J inches ; width, from the septum
laterally, i inch ; depth, from the surface backwards, between
the orbit below and the anterior cranial fossa above, f inch.
As the cavity is lined with muco-periosteum, which is continuous
with the nasal mucosa, the sinus may be infected secondarily to
nasal mischief. On the other hand the anterior and middle
ethmoidal cells are frequently infected by direct spread from a
diseased frontal sinus. The infundibulum, or duct of the sinus,
is not disadvantageously situated for drainage, but, owing to
small bony septa which may be present, loculi are sometimes
formed, and they prevent pus from draining away into the
nose.

Empysema of the Frontal Sinus can be recognised by trans-
illumination or radiograms (Fig. 59), and, by these means, the
position of the septum between the two sinuses can be ascertained.
This detail is of extreme importance, as the surgeon must be
certain of opening the infected sinus only. Retained pus in
the frontal sinus may find its way through the floor into the orbit,
and point at or near the medial palpebral commissure (inner
canthus).

The sinus is approached from in front by an incision which
follows the eyebrow, and may be extended medially and down-
wards on to the nose. After it has been opened up, the infun-
dibulum is enlarged so as to permit the passage of a drainage
tube down into the nose. In this process the anterior ethmoidal
cells, which are usually affected, are broken down, and the an-
terior extremity of the inferior concha (turbinated bone) will
probably require to be removed.

Fractures of the frontal bone may open into the frontal sinus
without involving the cranial cavity. In these cases, as in

THE FACE, MOUTH AND PHARYNX 201

fracture of the maxilla, there is every likelihood of surgical
emphysema, unless the patient is warned against blowing his
nose.

The Ethmoidal Air-Cells are all situated in the ethmoidal
labyrinth (lateral mass), and are only separated from the orbit

FIG. 59. — Empyaema of the Left Frontal Sinus.

by the thin lamina papyracea (os planum). On the medial
surface of the labyrinth are the projections which form the
superior and middle conchse (turbinated bones). The anterior
and middle ethmoidal cells open into the middle meatus, and
the posterior open into the superior meatus of the nose.

The Sphenoidal Sinuses are situated in the body of the
sphenoid and immediately below the fossa which lodges the

202 THE HEAD AND NECK

hypophysis (pituitary body). They are separated from one
another by a septum, which is usually deviated to one or other
side of the median plane. When these sinuses become infected,
the condition may spread upwards in front of the hypophysis
(pituitary body) and affect the optic chiasma, which lies above
the forepart of the body of the sphenoid , thus giving rise to
disturbance of vision. Collections of pus in the sphenoidal

FIG. 60. — -Lateral Radiogram of Skull. The relation of the sphenoidal
sinuses to the hypophyseal fossa (selki turcica) is well shown.

sinus can only be evacuated properly by removal of its anterior
wall. This is reached through the posterior ethmoidal cells,
which are usually involved, by removal of the middle and
superior conchae (turbinated bones).

Tumours of the Hypophysis (Pituitary Body) have recently been
removed through the sphenoidal sinuses. A somewhat U-shaped incision
is made round the nose, which is turned upwards after the nasal septum
has been removed and the lateral nasal cartilages divided.

By taking away the superior and middle conchae, better access can be
obtained. At a depth of 2^ inches from the surface the resistance of the an-
terior wall of the sphenoidal sinuses is encountered, and the wall is lightly
chiselled through. The septum between the sinuses is remoyedj and th?

THE EYE

203

postero-superior wall, which is usually much thinned, is opened very carefully
in the middle line, and the tumour is removed piecemeal. The lateral rela-
tions of the hypophysis (p. 225) are pushed aside by the growth of the tumour
and run little risk of injury. Lateral radiograms (Fig. 60) clearly demon-
strate the size of the fossa hypophyseos (sella turcica) and it is definitely
enlarged in these cases.

THE EYE.

The Eyelids. — The eyelids are supported by the tarsi (tar sal
plates), which consist of condensed fibrous tissue, and from

Levator palpebrse superioris
Superior fornix of conjunctiva ^ ^ ^

Ciliary process
nus venosus sclers
Posterior chamber
Superior tarsu

Iris

Cornea

Anterior

chamber

Lens

Inferior tarsu
Sinus venosus sclerse

Zonula ciliaris-
Orbicularis oculi

Inferior fornix of conjunctiv

Hyaloid canal

FIG. 61. — Diagram of a Sagittal Section through the Eye.

their margins the medial and lateral palpebral (tarsal) ligaments
extend to the medial and lateral borders of the bony orbit.
Each tarsus is separated from the skin by a muscular layer
and subcutaneous tissue, and the latter, being very loosely
arranged, is readily distended by effusions. Further, the skin
of the eyelid is so thin that an effusion of blood into the sub-
cutaneous tissue becomes apparent at once as a " black eye."
Numerous sebaceous glands are situated in the free margin of
the eyelid, and, when they become involved in suppurative
inflammation, they give rise to the condition known as a " stye."
The deep surfaces of the lids are lined by a mucous membrane,

204 THE HEAD AND NECK

the Conjunctiva, which is reflected from them on to the anterior
surface of the eyeball. The lines along which this reflection
takes place are termed the superior and inferior fornices of the
conjunctiva. Where it covers the cornea, the conjunctiva is
represented by a translucent layer of stratified epithelium.
The upper eyelid may be everted along the upper border of the
tarsus, and in this way the conjunctiva on its surface may be
exposed for the purpose of removing foreign bodies. E version
of the lid brings into view the tarsal or Meibomian glands, which
appear as yellow streaks near its free margin. It is therefore
from this surface that tarsal cysts, which are simply obstructed
tarsal glands, are excised. The sensory nerves of the conjunctiva
are all derived from the trigeminal (mainly supra-orbital
and infra-orbital branches). Blepharo-spasm and lacrimation
may be caused reflexly by the presence of foreign bodies or
by an inflammatory condition of the conjunctival sac. In
paralysis of the trigeminal, conjunctivitis or corneal ulceration
frequently results from the presence of particles of dirt, which
are unrecognised owing to the loss of sensibility. Ultimately,
the intra-ocular structures become affected and pan-ophthalmitis
ensues.

The arterial supply of the lids is derived from the ophthalmic
artery. The corresponding veins communicate with the oph-
thalmic veins, which join the cavernous sinus, and also with the
superficial temporal and anterior facial veins. On account of
the existence of this double channel of return, effusions into the
eyelids are absorbed with great rapidity. Both lids contain
a rich network of lymph vessels, and, as a result, drugs placed in
the conjunctival sac, in the form of lamellae, are quickly absorbed.
From the lateral half of the lids the lymph vessels pass to the
anterior auricular lymph gland, while those from the medial
half follow the course of the anterior facial vein, and pass through
the facial lymph glands, before terminating in the submaxillary
lymph glands.

The tarsi are connected to the upper and lower margins of
the orbit by fibrous tissue, which forms a sheet sufficiently strong
to delay a retro-tarsal haemorrhage from passing forwards into
the subcutaneous tissue of the eyelid. In fracture of the skull
involving the roof of the orbit, vthe haemorrhage appears first
under the margins of the conjunctiva, and then spreads in a
fan-shaped manner towards the cornea. The blood remains
red owing to the thinness of the conjunctiva and the consequent

THE EYE

205

transfusion of oxygen from the air. The haemorrhage may
descend between the superior tarsus and the conjunctiva, and
subsequently appear at the margin of the upper eyelid. Finally,
it may ascend on the outer surface of the tarsus and become
subcutaneous.

Subconjunctival haemorrhage may arise from the con-
junctival vessels as the result of a blow on the eye, but in these
cases the haemorrhage begins near the cornea.

The Lacrimal Gland lies in contact with the antero-lateral
part of the roof of the orbit. Its posterior portion rests on the
eyeball, but an-

' Lacrimal puncta
Lacrimal ducts

Lacrimal sac

Naso-lac

Maxillary sinu

Plica lacrimalis

Inferior tneatus

FIG. 62. — Diagram of the Naso-lacrimal Duct
and its Connections.

teriorly it is in con-
tact with the superior
fornix of the con-
junctiva, and this
portion of the gland
can just be made
out when the upper
eyelid is everted.
Numerous small
ducts leave the gland
and open into the
conjunctivalsac near
the superior fornix.
The tears pass across
the eyeball by the
action of gravity,
aided by the periodic
contractions of the

orbicularis oculi, and reach the puncta on the medial side. These
are small openings placed on the summits of papillae, which are
situated on the free margins of the lids near their medial ex-
tremities. They are kept in apposition with the conjunctiva by
the action of the inferior tarsal (tensor tarsi) muscle, which is
a part of the orbicularis oculi, and is supplied by the facial
nerve. The condition of epiphora results from the paralysis of
this muscle. The puncta lead into the lacrimal ducts, which at
first run for a short distance at right angles to the lid margins,
and then turn medially to enter the lacrimal sac (Fig. 62).

The Lacrimal Sac lies behind the medial palpebral (tarsal)
ligament. Abscesses in the sac should be incised just below
the ligament, the position in which they usually point, and

206 THE HEAD AND NECK

lateral to the termination of the external maxillary artery
(Stiles). The upper end of the sac is blind, but below it narrows
to form the naso-lacrimal duct, which opens into the inferior
meatus of the nose. This duct is about half an inch long, and
its lower end is protected by a fold of mucous membrane (the
plica lacrimalis). In cases of epiphora where a blockage of the
naso-lacrimal duct is suspected, a probe may be passed along it
from its upper end. The lower lid is everted, and the probe is
entered at the punctum and passed in for a short distance. It
is then passed medially along the duct into the lacrimal sac until
its medial wall is encountered. The hand is then elevated so
that the point of the probe is made to pass downwards and
slightly backwards and laterally into the nose. The direction
of the naso-lacrimal duct is indicated by a line joining the medial
palpebral commissure (inner canthus) to the interval between
the first molar and the second premolar tooth.

The Orbit and Eyeball.— The Fascia Bulbi (Capsule of
Tenon) is a layer of fascia which almost completely surrounds
the eyeball, and is continuous with the sheath of the optic
nerve behind. Anteriorly, it lies deep to the conjunctiva and
terminates at the corneo-scleral junction. The bellies of the
orbital muscles lie outside the fascia, but their tendons pierce
it to gain insertion into the sclera, and the fascia is prolonged
backwards upon them to fuse with the muscle sheaths. These
prolongations are particularly strong in relation to the lateral
and medial rectus muscles, and they are connected to the walls
of the orbit, an arrangement which checks lateral and medial
rotation of the eye (check ligaments}. They are connected to
one another by a thickened part of the fascia bulbi which lies
below the eye, forming the suspensory ligament of Lockwood.
It is this band, together with the orbital periosteum, which
supports the eyeball after excision of the maxilla (p. 198).

The Muscles of the Orbit. — The Levator Palpebrce Superioris
lies immediately under the orbital roof. It is supplied by the
oculo-motor nerve, and when that nerve is paralysed the con-
dition of ptosis results. The Superior Rectus rotates the eyeball
upwards and medially. It acts in unison with the Inferior
Oblique, which rotates the eyeball upwards and laterally. Both
are supplied by the oculo-motor nerve. The Inferior Rectus
rotates the eyeball downwards and medially, and acts in unison
with the Superior Oblique, which rotates it downwards and
laterally. The former is supplied by the oculo-motor and the

THE EYE 207

latter by the trochlear nerve. The Lateral Rectus, supplied by
the abducent nerve, and the Medial Rectus, supplied by the
oculo-motor, produce lateral and medial rotation of the eyeball.
Motor Nerves of the Orbit. — The Oculo-motor (third cerebral)
nerve supplies all the orbital muscles except the superior oblique
and the lateral rectus. In addition it gives off the short (motor)
root of the ciliary (lenticular) ganglion, and in this way supplies
the ciliary muscle and the sphincter pupillse. In complete
paralysis of the oculo-motor nerve, the pupil is widely dilated
by the dilatator pupillse (supplied by the sympathetic) and

Supra-orbital nerve
Levator palpebrae superioris | Ophthalmic vein

Roof of orbit • ; ;

Superior rectus ' i i Supra-trochlear nerve
Trochlear nerve
; Superior oblique

Naso-ciliary nerve

Lacrimal n^^J^^^fUS^Sf <ifck>< - Ophthalmic artery

Abducent nerve

Oculo-motor nerve, Jf^\
lower division

Middle concha
- Maxillary sinus

Infra-orbital nerve | Ophthalmic vein
Inferior rectus

FIG. 63. — Frontal Section through the Orbit, to show the relative
positions of the Muscles, Vessels and Nerves.

does not react to light. The power of accommodation to dis-
tance is lost, and ptosis is present. Owing to the unopposed
action of the lateral rectus, which is not involved, a divergent
strabismus results, and the patient carries his head rotated to
the opposite side in order to compensate for his disability.

The Trochlear (Fourth Cerebral) Nerve supplies the superior
oblique only. Paralysis of this nerve produces diplopia, when
the patient looks downwards, because, while pure downward
rotation is possible in the sound eye, the inferior rectus imparts
a medial as well as a downward direction to the eye on the affected
side, and the superior oblique, which should counteract the
medial rotation, is paralysed.

The Abducent (Sixth Cerebral) Nerve supplies the lateral rectus

208 THE HEAD AND NECK

muscle. When it is paralysed, the medial rectus is unopposed
and a convergent strabismus results. In an endeavour to com-
pensate for this disability, the patient carries his head rotated
to the affected side.

In the intracranial part of their course the motor nerves of
the orbit may be pressed on by the exudate of a basal meningitis
(p. 225), by haemorrhage following fractures of the base of the
skull, or by thrombosis of the cavernous sinus as they lie in its
lateral wall (p. 225).

Tenotomy of the Ocular Tendons is performed in cases of
strabismus which are due to congenital shortening of the medial
or lateral rectus muscles. An incision is made through the
conjunctiva near the margin of the cornea, and the underlying
fascia bulbi (capsule of Tenon) is opened. A blunt hook may be
inserted through the wound, and the desired tendon can be
drawn forwards and divided.

The Ophthalmic Artery is a branch of the internal carotid. It
supplies the muscles of the orbit, the lacrimal gland, and the
eyelids. Ciliary branches supply the eyeball, and the arteria
centralis retinae, which runs forwards in the optic nerve, is
distributed to the retina.

The Ophthalmic Veins communicate with the pterygoid
venous plexus through the inferior orbital (spheno-maxillary)
fissure, and with the anterior facial vein (p. 175). They pass
backwards through the superior orbital (sphenoidal) fissure and
join the cavernous sinus.

The Eyeball.— The Sclera, a strong fibrous membrane,
forms the outermost coat of the eye. Anteriorly, it lies deep to
the conjunctiva and the fascia bulbi and blends with the cornea.
It is supplied by branches from the ciliary arteries, and as these
vessels approach the corneo-scleral junction they send out
branches into the episcleral tissue, which form anastomosing
loops close to the margin of the cornea. From these loops
numerous small straight branches pass into the periphery of the
cornea, where they anastomose with one another. In inflam-
mation of the sclera these vessels become visible, and form the
" zone of ciliary injection."

The Cornea consists mainly of modified connective tissue.
Except at its extreme edge, it is non-vascular, but it is well
provided with spaces containing lymph, on which it depends for
its nutrition. The lymph is drained from the cornea by the
sinus venosus sclerce (canal of Schlemni).

THE EYE 209

In repair of inflammatory conditions of the cornea, the
newly formed connective tissue, not being specialised, may
cause opacities, which vary in degree from nebulae to leucoma.
Iridectoiny may be of value in certain cases, as it offers a larger
aperture for the transmission of light.

Internal to the sclera is the Chorioid, which supports the
ciliary vessels and contains numerous pigment cells. Anteriorly,
the chorioid is continuous with the Ciliary Body and the Iris.
The iris separates the anterior from the posterior chamber of
the eye. Its peripheral attachment is continuous behind with
the ciliary body and in front with the deepest layer of the cornea,
which it meets at an acute angle. A circular channel, the sinus
venosus sclerse (of Schlemm), is placed in the corneo-scleral
junction immediately opposite the angle between the iris and
the cornea (Fig. 61). The sinus is surrounded by numerous
lymph spaces, through which the aqueous humour and the
lymph from the cornea communicate with it and indirectly with
the ciliary veins. Obliteration of this angle by the formation of
adhesions prevents the proper drainage from the aqueous
humour, and causes increased intra-ocular tension and glaucoma.
The iris is richly supplied with blood, and the ciliary arteries
form anastomosing circles at its free and attached margins.

The optic nerve pierces the retina at a point a little medial to the posterior
pole of the eyeball. The papilla of the optic nerve (optic disc) is the physio-
logical " blind spot " of the retina. With the aid of the ophthalmoscope,
the central artery of the retina can be seen on the papilla breaking up into its
terminal branches. In all mammals which have binocular vision, the point
on the retina through which the antero-posterior axis of the eyeball passes
is highly specialised, and is known as the macula lutea.

The Vitreous Body, which occupies the greater part of the posterior chamber
of the eye, is surrounded by the hyaloid membrane. In front, the membrane
is attached to the ciliary body, and divides to form the suspensory ligament
which encloses the Crystalline Lens. When the ciliary muscle, which is con-
tained in the ciliary body, contracts, the suspensory ligament is drawn
forwards, and the pressure which it exerts on the anterior surface of the lens
is diminished. As a result, this surface becomes more convex, and diverging
rays of light become focussed on the retina.

The diameter of the crystalline lens is one-third of an inch, and this
measurement must be remembered in making the incision in the corneo-
scleral junction for its removal.

THE AUDITORY APPARATUS.

Development. — The outer cartilaginous portion of the ex-
ternal acoustic meatus is derived from the dorsal part of the

14

210 THE HEAD AND NECK

first visceral cleft, and the auricle is formed by the development
and fusion of several tubercles, which arise from the mandi-
bular and hyoid (first and second) arches. This double origin
is indicated in the adult by the double nerve supply from the
auriculo-temporal and great auricular nerves (pp. 108, 174).
Owing to faulty union of the various tubercles with one another,
pre-auricular fistulse may occur. The interval between the
helix and the tragus is the commonest site of this congenital
deficiency, and it is said to indicate the line of union between
the first and second arches.

The Tympanum or Tympanic Cavity and the Auditory (Eustachian) Tube
are the remains of the first visceral pouch (Fig. 46). They are enclosed in the
temporal bone, which consists of three pieces at birth. The Petromastoid
Portion encloses the internal ear, and forms the medial part of the roof and
the medial wall of the tympanum, the osseous part of the auditory tube, and
the tympanic (mastoid) antrum. The Squamous Portion forms part of the
lateral wall of the skull and of the tympanum, and the upper part of the
osseous external acoustic meatus. It also forms the lateral wall of the
tympanic antrum and the lateral part of the roof of the tympanum. The
Tympanic Ring forms the remainder of the osseous external meatus.
Although the tympanic antrum is present at birth, the mastoid process does
not begin to develop until the end of the second year, and the mastoid air-
cells begin to appear as outgrowths from the antrum at the same period.

The External Acoustic Meatus leads from the concha to the
membrana tympani. Its lateral cartilaginous portion is first
directed medially, forwards and upwards, and then, at a distance
of about a quarter of an inch from the surface, medially and
backwards to meet the osseous portion of the meatus, which is
directed medially, downwards and forwards. The membrana
tympani is obliquely placed so that the lower and anterior walls
of the canal are definitely longer than the upper and posterior.
The total length of the meatus is about one inch, and its
narrowest part is found at three-quarters of an inch from the
surface. In the examination of the tympanic membrane the
canal is straightened by drawing the auricle upwards and back-
wards. This procedure brings the cartilaginous portion into line
with the osseous portion, but in the infant the auricle must be
drawn downwards and backwards, as the canal is almost entirely
cartilaginous, and the outer surface of the membrana tympani
is directed mainly downwards.

The external acoustic meatus is lined by a layer of skin,
which is reflected over the outer surface of the tympanic mem-
brane. It is firmly bound down to the periosteum and peri-
chondrium, and therefore septic infections of the canal, although

THE AUDITORY APPARATUS 211

causing little swelling, give rise to severe pain. Chronic in-
flammatory processes may stimulate the periosteum to such an
extent that the new bone may occlude the canal almost entirely.
The cuticular lining is supplied by branches from the auriculo-
temporal nerve (p. 174) and the auricular branch of the vagus.
Stimulation of the latter nerve, by foreign bodies or collections
of wax, may produce symptoms so divergent as cough (internal
laryngeal nerve, p. 159) and dyspepsia (terminal branches of
vagus, p. 298). Similar irritation of the auriculo-temporal
nerve gives rise to pain, which may be referred to the side of
the head, to the teeth of the mandible, etc.

The cuticular lining of the canal possesses numerous cerumin-
ous glands ; and the wax which they secrete is normally carried
to the exterior by the movements of the mandibular condyle,
which presses against the anterior wall of the meatus. Sudden
deafness sometimes follows the entrance of water into the canal,
as it is readily absorbed by the wax, which swells up in con-
sequence.

The Membrana Tympani lies at the bottom of the external
acoustic meatus, and forms the greater part of the lateral wall
of the tympanic cavity. It consists of an outer cutaneous, an
inner mucous, and an intermediate fibrous layer. It is very
obliquely placed, so that its outer surface looks laterally, down-
wards and slightly forwards, i.e. the antero-inferior portion is
furthest removed from the surface.

When a normal tympanic membrane is examined with the
aid of reflected light, a well-marked depression, the umbo, can.
be recognised at a little below its centre. When the auditory
tube is obstructed the air in the tympanum becomes absorbed,
and the normal concavity is accentuated. The handle of the
malleus, which is attached to the fibrous layer of the membrane,
can be traced upwards and forwards from the umbo to a small
prominence, which is produced by the lateral (short) process
of the malleus. From this point the anterior and posterior
malleolar folds diverge in an upward direction, and bound the
flaccid part of the membrane (Fig. 64). The cms longum (long
process) of the incus may be discerned lying behind and parallel
to the handle of the malleus, though it lies on a deeper plane.
A cone of reflected light extends from the umbo over the antero-
inferior part of the membrane, and serves as a guide to the site
of puncture in the operation of paracentesis tympani, which is
carried out through the postero-inferior quadrant. This part of

14 a

212

THE HEAD AND NECK

the membrane is selected because it is furthest removed from the
handle of the malleus and the chorda tympani, and because it
affords good drainage. The nerve runs downwards and forwards
across the deep surface of the membrane, lateral to the crus
longum of the incus, but medial to the neck of the malleus.
The point of the knife must not be pushed too deeply through
the membrane as the tympanum is only one-eighth of an inch
wide at this point, and the fenestra of the cochlea (fenestra
rotunda), which lies on its medial wall, may be injured.

The Tympanum is about half an inch in length, and varies
from a tenth to a sixth of an inch in width. Its uppermost part,
known as the Epitympanic Recess (Attic), lies above the level of

Membrana flaccida

Anterior malleolar

plica

Manubrium mallei

Antero-superior
quadrant

Antero-inferior
quadrant

Posterior malleolar

plica

Lateral process of

malleus

Long crus of incus

Postero-superior
quadrant

Postero- inferior
quadrant

Cone of light

FiG. 64. — Left Tympanic Membrane (as viewed from the external
acoustic meatus). x 3.

the tympanic membrane, and contains the head of the malleus
and the body of the incus.

The Anterior Wall of the tympanum is formed by a thin
plate of bone, which separates the tympanic cavity from the
carotid canal. In the lateral part of this wall is situated the
opening of the auditory tube, which leads downwards, forwards,
and medially to the nasal pharynx. In the child the direction
of the tube is practically horizontal, the downward inclination
being very slight. The Koof is formed by the legmen tympani,
which separates the tympanum, the auditory tube, and the
tympanic (mastoid) antrum from the middle cranial fossa and
the temporal lobe of the brain. Its lateral border corresponds
to the line of the petro-squamous suture, which may remain
unossified until the end of the second year. Up to that age
inflammatory conditions of the brain or meninges may be caused

THE AUDITORY APPARATUS

213

by the upward spread of infection from the tympanum along
the veins which traverse the suture and terminate in the superior
petrosal sinus. The narrow Floor of the tympanum is formed
by the bone of the jugular fossa,, and lies below the level of the
lower border of the tympanic membrane. It is pierced by a
few small veins, which pass from the mucous membrane lining
the cavity to join the internal jugular vein. Septic thrombosis
of the latter may follow this course in otitis media. On the
Medial Wall, which separates the tympanum from the internal
ear, a slight elevation is present. It is produced by the first
coil of the cochlea, and is termed the promontory. The fenestra
of the cochlea (fenestra rotunda) is situated below and behind

Tympanic antrum

Fenestra vestibuli

Incus

Head of malleus
Tegmen tympani
Chorda tympani

Auditory tube

Promontory

Fenestra cochleae

Facial canal

I T-" Tympanic membrane
Facial canal

FIG. 65. — Section through a Left Temporal Bone along the line of the
Tegmen Tympani.

the promontory, and in life it is closed by a membrane which
separates the tympanic cavity from the scala tympani of the
cochlea. The fenestra of the vestibule (fenestra ovalis) is placed
at a slightly higher level. It is closed by the base (foot-plate)
of the stapes. The canal for the facial nerve produces a ridge,
which passes backwards above the promontory and downwards
behind it (Fig. 65). The Lateral Wall is formed mainly by
the tympanic membrane (p. 211). In the upper and medial
part of the Posterior Wall the epitympanic recess communicates
with the tympanic (mastoid) antrum through a short passage,
which is known as the aditus. The medial wall of the aditus
is crossed by the descending part of the ridge produced by the
facial nerve, and just above the ridge there is a slight promi-
nence due to the lateral semicircular canal. It is through the

14 b

214 THE HEAD AND NECK

aditus that infection reaches the tympanic antrum from the
tympanic cavity.

The Auditory Ossicles. — The handle of the malleus is very intimately
connected to the membrana tympani. Waves of sound impinging on the
membrane thrust the malleus medially, and the movement is conveyed through
it to the incus and stapes. Medial movements of the stapes set up a wave
in the perilymph of the scala vestibuli, and this wave passes up the cochlea
to the scala tympani. In the cochlea it stimulates the spiral organ of Corti,
and it is dissipated below, where it impinges on the membrane which closes
the fenestra of the cochlea (fenestra rotunda).

The Tensor Tympani occupies a small canal immediately above the
auditory tube. Its tendon is inserted into the upper part of the handle of
the malleus, and its contractions draw the bone medially, thus rendering the
tympanic membrane tense. It is supplied by a branch from the otic ganglion,
which lies on the lateral wall of the nasal pharynx, and obtains its motor fibres
from the mandibular division of the trigeminal. The Stapedius emerges
from a small opening in the posterior wall of the tympanic cavity, and is
inserted into the neck of the stapes. It is supplied by the facial nerve just
before it reaches the stylo-mastoid foramen. In paralysis of this nerve,
proximal to the origin of the branch to the stapedius, the condition of hyper-
acousis occurs as a result of paralysis of the muscle.

The auditory ossicles and the tendons of their muscles are all covered by
the mucous membrane, which extends backwards from the naso-pharynx
along the auditory tube, through the tympanic cavity and aditus into the
tympanic antrum and its furthest ramifications.

The Tympanic (Mastoid) Antrum, which is present at
birth, is relatively larger in the child than in the adult. It lies
behind and slightly above the tympanic cavity, with which it
communicates thiough the aditus. Its lateral wall, formed
by the squamous portion of the temporal, is only one-sixteenth
of an inch thick at birth, but by the ninth year it has increased
to nearly half an inch. The floor and medial wall, formed by
the petrous portion of the temporal, separate the antrum from
the posterior cranial fossa and the descending portion of the
transverse (lateral) sinus, which forms a deep groove on the in-
ternal surface of the mastoid portion of the temporal bone.
The aditus is placed above the level of the floor, and consequently
can only act as an overflow when the antrum contains fluid.
The roof is formed by a backward continuation of the tegmen
tympani.

As the mastoid process develops at the end of the second
year its diploe is gradually replaced by air-cells, which are
derived from the antrum and maintain their connection
with it, either directly or indirectly through neighbouring cells.
Occasionally the process is entirely hollowed out by air-cells, the
pneumatic type, or it may be practically solid, the sclerosed
type. Various intermediate forms occur. The cells which lie

THE AUDITORY APPARATUS 215

in relation to the posterior wall of the external acoustic meatus
are termed the " border cells," and when filled with pus they
may rupture into the meatus and discharge through it.

Septic infection may spread from the tympanic antrum
(i) directly, by necrosis of bone, (2) by venous thrombosis, or
(3) by the lymph vessels.

Upward Spread of Infection, which may or may not be
accompanied by destruction of the tegmen tympani, may cause
an extra-dural abscess in the middle cranial fossa or an abscess
in the temporal lobe of the brain. The veins which ascend
through the petro-squamous suture open into the superior
petrosal sinus, and through them the latter may become the
site of a septic thrombosis. Downward Spread involves the
internal jugular vein (p. 213).

By necrosis of the lower part of the medial wall of the antrum
pus may pass downwards and medially, and reach the mastoid
notch (digastric fossa) — Bezold's mastoiditis. It then passes
downwards along the styloid process and the muscles attached
to it, and gives rise to a deep-seated and dangerous form of
cervical cellulitis. Backward Spread involves the transverse
(lateral) sinus, and may pass along the cerebellar veins, producing
a cerebellar abscess. Forward Spread infects the " border cells,"
and thence the pus may reach the external acoustic meatus,
or may spread laterally and produce an abscess which points on
the surface under cover of the auricle. When the pus reaches
the outer surface of the bone it strips up the periosteum and
forms a subperiosteal abscess. This accounts for the dis-
placement of the auricle in a downward and forward direction.
Abscesses in connection with the mastoid lymph glands (p. no)
lie superficial to the periosteum, and although they may displace
the auricle forwards, they are never accompanied by downward
displacement. Necrosis of the medial wall of the aditus exposes
the facial nerve, and infection may pass along its sheath to the
base of the brain, setting up a suppurative basal meningitis.

Tuberculous disease of the temporal bone, a common condition
in children, may spread in any of the directions which have just
been described. In this case, and also in chronic otitis media,
the anterior auricular and the upper anterior group of the deep
cervical lymph glands are usually enlarged.

The Surgical Approach to the Tympanic Antrum is
made through a curved incision, which commences a quarter
of an inch above the upper attachment of the auricle and extends

14 c

216 THE HEAD AND NECK

downwards behind it on to the mastoid process. In the infant,
prior to the development of the mastoid process, the facial
nerve runs serious risks of injury if the incision is carried too
far forwards, because its point of exit from the skull, the stylo-
mastoid foramen, is situated on the infero-lateral aspect (p. 210).
The incision is carried down to the bone, and the periosteum and
soft structures of the flap are dissected forwards until the
osseous part of the external acoustic meatus is visible, and the
suprameatal spine and the posterior root of -the zygomatic pro-
cess of the temporal bone are recognised. If the posterior edge
of the incision is elevated, an emissary vein is exposed emerging
from the mastoid foramen, through which it communicates with
the transverse sinus. When it is found thrombosed, the sinus
will be similarly affected. Pus may sometimes be seen emerging
from the mastoid foramen, and its presence indicates that pus
will be found in the transverse sinus and is suggestive of a sub-
dural abscess.

In chiselling through the bone to reach the antrum, care must
be taken not to do so too high, lest the middle cranial fossa be
opened, or too far posteriorly, lest the transverse (lateral) sinus
be injured. The site selected lies below the posterior root of
the zygomatic process and immediately behind the supra-
meatal spine. In the child, however, these bony prominences
are not developed, and the bone lying just behind the postero-
superior quadrant of the external acoustic meatus is the best
guide (Stiles). The chisel is directed medially, downwards and
forwards, i.e. parallel to the external acoustic meatus. It is
advisable to bevel down the edges as the opening is deepened,
and if the transverse sinus lies further forwards than normally,
its bluish wall will be observed and can be protected. As a rule
the sinus lies half an inch behind the external acoustic meatus,
but its position is subject to variation (p. 225).

As soon as a cavity is reached, a probe is inserted and directed
forwards in search of the aditus. The sensation produced as
the probe slips into the passage is unmistakable, and if it is not
experienced, the cavity, which is only an air-cell, is deepened
until the antrum is opened. It may be necessary to remove
the lateral wall of the aditus in order to throw the two cavities —
tympanic cavity and antrum — into one. Before this is carried
out, a Stacke's protector is passed into the aditus from the
antrum, to preserve the facial nerve and the lateral semicircular
canal (p. 213) from injury should the chisel accidentally slip

THE AUDITORY APPARATUS 217

during the operation. Occasionally, when the lateral wall of
the aditus is being removed, the bone breaks away owing to the
weakness caused by the facial canal (aqueduct of Fallopius),
and a short piece of the facial nerve is exposed. This may be
bruised during the remaining steps of the operation, or it may
be pressed upon by the packing, etc., leading to a complete but
transitory facial paralysis. Any irritation of the nerve sets up
a spasm of the facial muscles, and the anaesthetist is able to warn
the surgeon. When the antrum and tympanic cavity are
syringed out, some of the fluid used may pass along the auditory

Lateral semicircular canal Posterior semicircular canal

Remains of posterior .• Temporal line

wall of external meatus / , r

Wall of groove for
sigmoid part of
transverse sinus

Tympanic plate '

Styloid process '^ Wan ?f canalis
facialis

FIG. 66. — Dissection of the Tympanic (Mastoid) Antrum and the petro-
mastoid part of the Temporal Bone from the outer side. The arrow
is passing through the aditus from the tympanic antrum into the
tympanic cavity.

tube into the nasal pharynx, and the anaesthetist must be pre-
pared to prevent it from passing down into the larynx.

The mucous membrane of the tympanic cavity, together
with the incus and malleus, may require to be removed ; but
the stapes, which is firmly attached to the fenestra of the vesti-
bule (fenestra ovalis), is left in situ, as otherwise the internal
ear would be opened.

After the antrum has been dealt with, the opening may be
enlarged upwards and forwards to explore the middle cranial
fossa (p. 231), or backwards to explore the transverse sinus
and cerebellum (p. 216), if the symptoms point to a spread of the
disease in either direction.

2i8 THE HEAD AND NECK

THE HEAD.

Bony Landmarks. — The External Occipital Protuberance
lies just above a small depression, which indicates the upper end
of the nuchal furrow when the head is held erect. Two inches
above it in the median line the Lambdoidal Suture can be recog-
nised as an irregular depression. The Parietal Tuber (Eminence),
which overlies the supra-marginal convolution of the brain,,
can be felt on the side of the skull about two inches above the
auricle. It is crossed by the Superior Temporal Line (Crest),
which can be traced downwards and forwards to the zygomatic
(external angular) process of the frontal bone, and downwards
and backwards to a point a little above and behind the mastoid
process. The Asterion, which corresponds to the articulation
of the mastoid (postero-inferior) angle of the parietal bone with
the temporal, forms a depression above and behind the external
acoustic meatus. It lies about midway between the Sylvian
point (p. 229) and the external occipital protuberance. Other
bony landmarks have been dealt with on pp. 170, 171.

The Skin of the Scalp contains a large number of sebaceous
glands, and is therefore a common site for sebaceous cysts or
wens. These swellings are embedded in the superficial fascia,
which in this region consists of a dense network of fibrous tissue
containing very small lobules of fat. They can be moved with
the scalp, and this feature distinguishes them from tumours in
connection with the pericranium.

Numerous arteries supply the scalp, ramifying for the most
part in the subcutaneous layer. They are derived from both
the external and the internal carotid arteries, and ascend to-
wards the vertex from the orbit, face, and neck. A free anasto-
mosis occurs between the two groups of vessels and across the
median line. In consequence, ligature of one external carotid
fails to cure a cirsoid aneurism of the superficial temporal artery.
Subcutaneous haemorrhage is limited in amount owing to the
density of the tissue, and for the same reason superficial septic
infections remain localised and are extremely painful. When
one of these vessels is cut the bleeding is plentiful, as its wall
is held open and prevented from retracting by its attachment
to the fibrous septa. At the same time the density of the sub-
cutaneous tissue renders the cut vessels difficult to catch, but
moderate pressure usually suffices to stop the haemorrhage.

THE HEAD 219

Owing to its rich blood-supply, the scalp possesses remarkable
vitality. Large areas may be stripped up, and although they
may only remain attached by narrow pedicles, if replaced they
will heal with little loss from sloughing.

Vessels and Nerves of the Scalp. — The Superficial Temporal Arteries
supply the lateral aspects of the scalp and ascend to the vertex to anasto-
mose with one another. They divide into frontal (anterior) and parietal
(posterior) branches, which communicate freely with the supra-orbital and
frontal arteries in the forehead and with the posterior auricular and occipital
arteries behind the auricle. The superficial temporal artery is accompanied
by the Auricula- Temporal Nerve.

The Supra-Orbital and Frontal Arteries accompany the Supra-Orbital and
Supra-Trochlear Nerves (Fig. 59). They are branches of the ophthalmic
artery, which arises from the internal carotid.

The Posterior Auricular Artery runs backwards and upwards from the
external carotid, and lies superficial to the mastoid process. It supplies the
auricle and adjoining area of the scalp, and is accompanied by the terminal
branches of the Great Auricular (p. 108) and the Lesser Occipital Nerves
(p. 108).

The Occipital Artery (p. 122) supplies the back of the scalp, and its branches
accompany those of the Greater Occipital Nerve (p. 138).

The Galea Aponeurotica (Epicranial Aponeurosis) is a

thin tendinous sheet which unites the frontal and occipital bellies
of the epicranius (occipito-frontalis) to one another. Unless
it is cut through in a transverse direction, scalp wounds do not
tend to gape. Its lateral margins blend with the strong tem-
poral fascia, and, together with the line of origin of the muscular
bellies, completely shut in the subaponeurotic space which separ-
ates the galea aponeurotica from the pericranium. This space
only contains some loose connective tissue and a few small
arteries, but it is traversed by the important emissary veins
which connect the intra-cranial venous sinuses and the superficial
veins of the scalp. When pus collects in this region it can spread
in all directions so as to elevate the scalp, which feels to the ex-
amining fingers as if it were lying on a water-bed. Incisions for
the evacuation of such a collection are made near its lower
border and parallel to the larger blood-vessels. The pus may
destroy the pericranium and cause necrosis of the bones of the
skull ; and it may produce septic thrombosis of the emissary
veins, and emboli may spread to the intra-cranial sinuses. On
this account the subaponeurotic space is frequently referred to
as the Dangerous Area.

The Venous Return from the Scalp may pass by (i) the
extra-cranial or (2) the intra-cranial route.

I, The extra-cranial route is constituted by the veins corre-

220

THE HEAD AND NECK

spending to the branches of the external carotid artery which
are found in the scalp, and by the supra-orbital and frontal
veins which unite to form the angular vein (p. 175).

FIG. 67. — Diagrammatic Representation of a Frontal Section through the
Scalp, Cranium, Meninges, and Cortex Cerebri (modified from Cunningham).

1. Integument.

2. Artery in superficial fascia.

3. Vein in superficial fascia.

4. Diploic vein, connecting veins of scalp

with veins of dura mater.

5. Vein in dura mater.

6. Arachnoid.

7. Pia mater.

8. Arachnoidal granulation.

9. Cortex cerebri.

TO. Superior sagittal sinus.

11. Vein in pia mater.

12. Sub-arachnoid space.

13. Epicranial aponeurosis.

14. Lax connective tissue.

15. Pericranium.

16. Outer table of cranium.

17. Diploe.

1 8. Anastomosis between arteries of scalp

and those of dura mater.

19. Inner table of cranium.

20. Dura mater.

21. Parasinoidal sinus.

22. Cerebral vein opening into superior

sagittal sinus.

2. The venous blood may return along the parietal emissary
vein into the superior sagittal (longitudinal) sinus, or along the
mastoid and condyloid emissary veins into the transverse (lateral)
sinus. Further, the supra - orbital veins communicate with

THE HEAD 221

the ophthalmic veins, and by this route venous blood may be
returned from the scalp to the cavernous sinus.

In addition to those mentioned above> emissary veins con-
nect the superior sagittal (longitudinal) sinus with the veins of
the nasal mucous membrane through the foramen caecum, and
the cavernous sinus with the pterygoid venous plexus. Epi-
staxis is common in children during a fit of violent temper or of
crying, and it serves to reduce the intra-cranial blood-pressure.
In this way the emissary veins may act as safety valves.

The Pericranium covers the outer surface of the skull and is
easily stripped off except at the sutures, where it is connected
with the endo-periosteal layer of the dura mater. The latter
provides the bones of the skull with their blood-supply, and on
this account removal of portions of the pericranium, in operations
for tuberculous periostitis of the skull, is not necessarily followed
by death of the exposed bone. A sub-pericranial haemorrhage,
or cephal-hccmatoma, is limited to the surface of some particular
bone by the inter-sutural membrane. It is probably due to the
rupture of some of the inter-sutural veins during the moulding
of the fcetal head, and can easily be distinguished from the
swelling produced by Caput Succedaneum, as the latter occurs in
the scalp and is not limited to the surface of any particular bone.

The Developing Cranium expands rapidly to accommodate
itself to the rapidly growing brain. At first it consists of a
membranous capsule, but supporting cartilaginous bars soon
appear in its base. The bars become ossified, and at the same
time centres of ossification appear in the membrane to form the
parietal bone and the squamous portions of the temporal,
occipital, and frontal bones. In the regions of the anterior and
posterior fontanelles the membrane is the only covering of the
brain and its meninges at birth. The anterior fontanelle is
placed at the area where, in the adult, the coronal and sagittal
sutures meet, and through it the pulsations of the brain can
readily be seen and felt. It should be closed by the end of the
second year, but in rickets it is still widely open at that age.
When the intra-cranial pressure is raised, e.g. in crying, the
anterior fontanelle becomes tense, while it is sunken in con-
ditions of malnutrition and exhaustion. Faulty development
of the skull at the suture lines is accountable for the various
forms of meningoceles (p. 534).

The cranial deformities produced by hydrocephalus (p. 226)
are determined by the condition of the sutures at the time of

222 THE HEAD AND NECK

the onset of the disease. If it occurs after the closure of the
sagittal suture, the frontal and occipital regions are both affected,
but if the lambdoidal suture is also closed the bulging is confined
to the region of the forehead.

Fracture of the Skull. — In relation to cranial injuries
haemorrhage alone is of very little diagnostic value, but the
accompanying or subsequent discharge of cerebro-spinal or
subdural fluid is positive evidence of a fracture of the skull.

Anterior Fossa. — Fracture of the lamina cribrosa of the
ethmoid bone is usually accompanied by laceration of the mucous
membrane of the roof of the nose. This injury, therefore,
gives rise to epistaxis, accompanied or followed by a discharge
of cerebro-spinal fluid. In addition, there is frequently some
loss of smell due to laceration of the olfactory nerves as they
pass upwards from the nose. In fracture of the orbital part
(plate) of the frontal bone, sub-conjunctival ecchymosis is a
characteristic feature, and the haemorrhage within the orbit
may produce exophthalmos. When the frontal air sinus is
also injured, blood may pass down the infundibulum to the middle
meatus and be discharged from the nose. In these cases the
haemorrhage arises from the torn branches of the anterior
division of the middle meningeal artery or, more rarely, from
the ophthalmic vessels. Some of the blood may be swallowed,
giving rise subsequently to hsematemesis.

Middle Fossa. — This is the commonest site of fracture of the
skull, partly because of its position but also because it is weak-
ened by numerous canals and foramina. The tegmen tympani
(p. 212) is usually fractured, and the tympanic membrane is
torn. Blood and cerebro-spinal fluid are discharged from the
external acoustic meatus, and the facial and auditory (seventh
and eighth cerebral) nerves may be involved (p. 213). Some-
times the walls of the cavernous sinus are lacerated, and some
of the nerves (third, fourth, and sixth cerebral) which lie in its
lateral wall are paralysed (p. 225).

Posterior Fossa. — In this case the haemorrhage does not
become evident at once, unless the basilar part of the occipital
bone is fractured, with laceration of the mucous membrane of
the pharyngeal roof. Otherwise the blood is situated deeply
at the back of the neck, and the discoloration does not become
apparent for some days. It reaches the surface in the posterior
triangle or in the neighbourhood of the mastoid process.

THE BRAIN AND ITS MENINGES 223

THE BRAIN AND ITS MENINGES.

The Dura Mater is a fibro-serous membrane. The fibrous
layer forms the endo-periosteum of the skull, to which it is
attached by numerous fibrous processes, but it is only strongly
adherent over the floor of the cranial fossae and along the suture
lines. The meningeal vessels lie between the dura mater and
the bone, and, owing to the ease with which the membrane
may be stripped off, extra-dural blood-clots may attain a suffi-
ciently large size to exert a fatal degree of intra-cranial pressure.
The serous layer forms a covering for the brain and supports the
thin endothelial walls of the cranial blood sinuses, which, conse-
quently, do not collapse when they are wounded. The falx
cerebri is a fold of the serous layer, which passes downwards in
the middle line between the two cerebral hemispheres. Pos-
teriorly, a similar fold, termed the tentorium cerebelli, projects
inwards between the cerebellum and the cerebrum ; and the
two cerebellar hemispheres are partially separated by the falx
cerebelli, a small fold which extends from the internal occipital
protuberance to the posterior border of the foramen magnum.

The Superior Sagittal (Longitudinal) Sinus lies in the
upper margin of the falx cerebri (Fig. 68). It begins at the fora-
men caecum, where it communicates with the nasal veins (p.
221), and runs backwards to the internal occipital protuberance.
At this point it communicates with the straight sinus, and turns
laterally, usually to the right, to form the transverse sinus.
It is half an inch in breadth posteriorly, and, therefore, trephine
openings should not be made less than three-quarters of an inch
from the median line. In addition to the parietal emissary vein
(p. 220), it receives numerous cerebral veins, which run forwards
and medially to enter the sinus. Backward movements of the
head, which tend to empty the sinus, retard the outflow from
the cerebral veins, owing to their forward inclination.

The Inferior Sagittal Sinus lies in the lower border of the
falx cerebri, and is joined posteriorly by the great cerebral
vein (of Galen) to form the Straight Sinus, which runs back-
wards on the upper surface of the tentorium cerebelli and in the
base of the falx cerebri. At the internal occipital protuberance
the straight sinus bends laterally to form the transverse sinus,
usually of the left side, but at its termination it communicates
freely with the superior sagittal sinus.

224

THE HEAD AND NECK

The Transverse Sinus runs laterally and slightly upwards
from the internal occipital protuberance; grooving the occipital
bone. Its highest point is placed on the mastoid (postero-
inferior) angle of the parietal bone,, and it then turns downwards,,
forming a deep groove on the mastoid portion of the temporal
bone. Its horizontal part lies in the attached margin of the
tentorium cerebelll.(Fig. 68) , but its vertical portion lies in the
lateral wall of the! posterior cranial fossa and is situated behind
the tympanic . (mastoid) antrum (p. 214). At its termination
it runs medially and then forwards to reach the jugular
foramen, through which it passes to become continuous with

Superior sagittal sinus
Fossae for occipital lobes

Falx cerebri

Straight sinus

Transverse'sinus

Fossae for cerebellum

Transverse sinus

Occipital sinus

FIG. 68. — Oblique Section through Posterior part of Skull, showing the
relationship of the Dura Mater to the Cerebral Sinuses. The fibrous
layer of the dura mater is shown in blue, and the serous layer in red.

the internal jugular vein. It receives the mastoid emissary vein
(p. 216) and tributaries from the cerebellum and the lower part
of the lateral surface of the cerebrum.

The transverse sinus corresponds roughly to the superior
nuchal (curved) line on the occipital bone. In mapping it out
on the surface it must be borne in mind that the sinus is about
one-third of an inch wide. It commences a little above the
external occipital protuberance and runs laterally to the asterion
(p. 218). In this part of its course the sinus presents a varying
degree of upward convexity, but the summit of its curve is
rarely higher than a point one ringer's breadth above the middle
of the line joining the external occipital protuberance to the
centre of the external acoustic (auditory) meatus. The descend-

THE BRAIN AND ITS MENINGES 225

ing part of the sinus runs downwards and slightly forwards to
a point three-quarters of an inch below and behind the centre
of the meatus. Very often, however, it approaches nearer to
the meatus, and in this event it may be exposed during opera-
tions on the tympanic (mastoid) antrum.

The Cavernous Sinuses lie one on each side of the body
of the sphenoid and are separated by the hypophysis (pituitary
body), but they communicate freely with one another. An-
teriorly, the cavernous sinus receives the ophthalmic veins,
and posteriorly the blood is drained into the transverse sinus
by the superior petrosal, and into the commencement of the
internal jugular vein by the inferior petrosal sinus. The cavern-
ous sinus communicates with the pterygoid venous plexus
through the foramen ovale and the foramen of Vesalius. Be-
tween the endothelial wall of the sinus and the serous layer cf
the dura mater which supports it laterally, the third, fourth,
and sixth cerebral nerves and the ophthalmic division of the fifth
pass forwards to the orbit (p. 207), and a similar position is
occupied by the internal carotid artery. Any or all of these
structures may be involved by (i) tumours of the hypophysis
(pituitary body) which extend in a lateral direction, (2) throm-
bosis of the sinus, (3) fractures of the skull in this region.

The Occipital Sinus (p. 227) lies in the attached border
of the falx cerebelli, and runs upwards to join the right or left
transverse sinus near its commencement.

The Arachnoid and the Pia Mater are two membranes
which are applied to the surface of the brain more closely than
the dura mater. The pia mater dips into all the fissures, but the
arachnoid only does so in the case of the longitudinal fissure
and the lateral fissure (of Sylvius). In certain areas the two
membranes are separated by the subarachnoid cisterns. Of
these the most important are situated on the basal surface
of the brain, and in basal meningitis they become filled with
purulent exudates, which may press on the neighbouring
cerebral nerves (second to the eighth inclusive).

The Ventricular System of the Brain and Spinal
Medulla. — The central canal is a small channel which extends
upwards through the whole length of the spinal medulla into
the medulla oblongata, where it expands to form the fourth
ventricle. From the upper part of the fourth ventricle the
cerebral aqueduct (of Sylvius} passes through the mid-brain to
open into the third ventricle, which in its turn communicates

15

226

THE HEAD AND NECK

with the lateral ventricles through the inter-ventricular foramina
of Monro. The whole of this system is lined by ependyma, a
thin membrane covered by ciliated columnar epithelium.
The cerebro- spinal fluid fills the ventricular system, and normally
drains away through certain apertures in the walls of the
ventricles into the subarachnoid space. The largest of these
apertures (the foramen of Magendie) is placed in the lower

Higher motor centres for lower limb

Central sulcus
Cerebral aqueduct

Higher
visual centres

Sulcus cinguli

| Corpus callosum

Interventricular foramen
(of Monro)

cut

ophysis

Cisterna interpeduncularis
Midbrain
s

edian aperture of fourth ventricle
(foramen of Magendie)
Medulla oblongata

x'Cisterna cerebello-medullaris
""-, Central canal of spinal medulla

FIG. 69. — Median Section through the Brain. The arachnoid
is shown in blue.

Fourth ventricle

part of the roof of the fourth ventricle. The cerebro-spinal
fluid passes through the arachnoid by a process of osmosis into
the sub-dural space, where it mixes with the sub-dural fluid
and ultimately becomes absorbed. It is derived from the
veins of the chorioid plexus, which invaginate the ependyma
and project into the cavities of the lateral and fourth
ventricles.

Congenital Hydrocephalus is said to be due (i) to an in-
crease in the amount of cerebro-spinal fluid secreted or (2) to
a diminished rate of absorption. On the ground of the former

THE BRAIN AND ITS MENINGES 227

theory Stiles treats the condition by ligature of the common
carotid arteries (p. 119).

Acquired Hydrocephalus may be caused by obstruction to
the outflow into the subarachnoid space (p. 226) by adhesions fol-
lowing meningitis, or it may be produced by pressure on the great
cerebral vein (of Galen). In the latter case the veins of the
choroid plexus become conges ted, and increased transudation
takes place through the ependyma into the interior of the ven-
tricles. In the former case the condition may be cured by mak-
ing a fresh opening in the roof of the fourth ventricle so as to
re-establish the communication between the ventricular system
and the subarachnoid space. In this operation an anchor-
shaped incision is employed. The curved base of the anchor
lies along the superior nuchal (curved) lines of the occipital bone,
and from its centre a vertical incision passes downwards along
the ligamentum nuchae. The knife is carried down to the bone
and the two flaps are reflected downwards and laterally. The
skull is opened below the level of the transverse sinus (p. 224)
and at the thinnest part of the occipital bone, to one side of the
median line. The opening is enlarged by removing the lower
portion of the squamous part of the occipital bone piecemeal,
including the posterior margin of the foramen magnum as far
forwards as the posterior edges of the condyles. During the
process considerable oozing occurs from injured diploic veins.
The occipital sinus is ligatured above and below, and the dura
mater is then opened along one side of the sinus. Horizontal
incisions are made at each end of this cut, and two flaps of dura
mater, one of which contains the ligated portion of the occipital
sinus, are turned laterally. This step exposes the postero-
inferior aspect of the cerebellum, covered by the arachnoid and
the pia mater. The cerebellum is pressed upwards, away from
the posterior aspect of the medulla oblongata (Fig. 69), and a
large subarachnoid cistern (cerebello- medullary) is brought
into view. After the cistern is opened, the lower part of the
bulging roof of the fourth ventricle, which consists of ependyma
and pia mater, is exposed, and the communication between the
ventricular system and the subarachnoid space may be re-
established.

The operation of suboccipital decompression, as practised by
Gushing, follows the same course as far as the incision of the
dura mater.

In evacuating a cerebellar abscess the same route is adopted.

15 a

228

THE HEAD AND NECK

After the membranes have been opened, a director is passed
into the substance of the cerebellum at the point where the
bulging is greatest. The instrument must not be passed in

70. — Cranio-Cerebral Topography. The figure shows the positions of
the motor and sensory areas and their relations to Chiene's lines.

G.
O.
M.
T.
S.
E.
P.
N.
R.
C.

Glabella.

External occipital protuberance.
Mid-point between G and O.
Mid-point between M and O.
Mid-point between T and O.
Zygomatic process of frontal.
Pre-auricular point.
Mid-point of EP.
Mid-point of PS.
Mid-point of AB.

CD is drawn parallel to AM.

Z. Post-auricular point.

VW. Guide to anterior limit of transverse

sinus.

Y. Tympanic antrum.
X1. Site nt which sub - arachnoid space

may be opened.
X2. Site for draining lateral ventricle

(Kocher).
X3. Site for draining lateral ventricle

(Keen).

for more than i J inches, and it may be withdrawn and reinserted
in different directions till the pus is found.

The Lateral Surface of the Cerebral Hemisphere.—
The Central Sulcus (of Eolando) crosses this surface of the

THE BRAIN AND ITS MENINGES 229

brain obliquely and separates the frontal from the parietal
lobe. It begins at the supero-median border and runs down-
wards, forwards, and laterally to end a little above the posterior
ramus of the lateral fissure (of Sylvius). The Anterior and
Posterior Central (Pre- and Post-Central) Gyri are two parallel
and nearly vertical convolutions, which lie one on each side of
the central sulcus. The motor area is situated in the grey matter
of the anterior central gyrus and in the anterior wall of the
central sulcus (of Rolando), but it does not extend on to the
surface of the posterior central gyrus. In front of the lower end
of the sulcus, the motor centre for the face is situated, and above
lie the centres for the neck, upper limb, trunk, and lower
limb, in that order. The last-named extends from the supero-
median border on to the upper part of the medial surface of the
hemisphere (Fig. 69).

The upper end of the central sulcus (of Rolando) corresponds
to a point half an inch behind the mid-point of the line joining
the nasion to the external occipital protuberance. The sulcus
itself can be mapped out by drawing a line, inclined at an angle
of 67!° to the sagittal suture, downwards and forwards from
this point for 3! inches. The direction of this line can be in-
dicated on the head by placing the palm upon the scalp with the
index-finger along the median line and the thumb extended so
as to point just behind the apex of the chin. When the apex
of the angle between the thumb and the index-finger corresponds
to the commencement of the sulcus, the thumb itself indicates
the situation of the sulcus on the surface. The motor area
extends forwards for half an inch in front of this line. It is
crossed by the superior temporal line at or near the lower part
of the upper limb centre, and, therefore, that part of the skull
which overlies the face centre is itself covered by the temporal
muscle and fascia. In the child, owing to the smaller size of
the muscle, the temporal lines lie entirely below the level of the
motor area.

The Lateral Fissure of Sylvius breaks up into three rami as soon as it
appears on the lateral surface of the brain. The point at which this takes
place lies ij inches vertically above the mid-point of the zygomatic arch. It
is known as the Sylvian point and is situated opposite the Pterion, the region
where the great wing of the sphenoid articulates with the sphenoidal (antero-
inferior) angle of the parietal bone. The anterior horizontal and anterior
ascending rami extend on to the inferior frontal gyrus, and the convolutions
which surround them are known as Broca's Area. This area is said to contain
the motor speech centre, which is only developed on the left side of the brain.
It lies immediately above the Sylvian point.

156

230 THE HEAD AND NECK

The Posterior Ramus of the lateral fissure of Sylvius runs backwards,
forming the upper boundary of the temporal lobe ; and, posteriorly, it turns
upwards into the parietal lobe. It may be mapped out on the surface by
drawing a line from the Sylvian point backwards for three inches in the
direction of the lambdoidal suture and then upwards for one inch. At its
termination the ramus lies under cover of the parietal tuber (eminence), and
is surrounded by the supra-marginal convolution. The word-hearing centre
is placed in the superior temporal gyms, below the middle part of the pos-
terior ramus. Immediately behind the supra-marginal convolution lies the
angular gyrus, which contains the word-seeing centre. It can be exposed by
trephining the skull a little below and behind the parietal tuber.

The occipital lobe is covered by the upper part of the squamous portion
of the occipital bone. It contains the higher visual centres, but they are
situated chiefly on its medial surface.

The Middle Meningeal Artery (p. 181) enters the skull
through the foramen spinosum, and runs laterally and slightly
forwards over the floor of the middle cranial fossa between the
dura mater and the bone. One finger's breadth above the mid-
point of the zygomatic arch, it divides into anterior and posterior
branches. The former runs upwards and crosses the deep sur-
face of the pterion opposite the Sylvian point, and is then con-
tinued upwards along the anterior border of the motor area.
The posterior branch runs backwards parallel to the posterior
ramus of the lateral fissure of Sylvius and about three-quarters
of an inch above the level of the zygomatic arch.

Surgical Approach to the Middle Cranial Fossa.—
The middle cranial fossa is opened in operations in connection
with the semilunar (Gasserian) ganglion, in ligature of the
branches or main trunk of the middle meningeal artery, and in
subtemporal decompression. The approach is very much the
same in each case. The incision divides the skin and superficial
fascia from the zygomatic (external angular) process of the
frontal bone along the superior temporal line, and descends
posteriorly to a point in front, above, or behind the auricle, as
the case may be. In this way the upper branches of the facial
nerve, which lie parallel to and a little below the base of the
flap, are preserved intact. The flap thus mapped out is turned
downwards till the zygomatic arch is reached. The skull may
be exposed by turning down a flap, consisting of the temporal
fascia and muscle, or the fascia alone may be dissected down-
wards and the muscle may be split and each half retracted
(Cushing's intermusculo-temporal method in ligature of the
anterior division of the middle meningeal artery).

The point of application of the trephine varies with the
individual operation. After a circular disc of bone has been

THE BRAIN AND ITS MENINGES 231

removed the opening is enlarged by means of craniectomy
forceps. The inner blade of this instrument is blunt, and
formed so as to separate the dura mater from the inner surface
of the skull while the bone is being removed.

(a) In Ligature of the Anterior Division or of the Main
Trunk of the Middle Meningeal Artery the trephine is applied
over the Sylvian point (p. 229), and, when the disc of bone is
removed,, the anterior division is exposed running upwards over
the dura mater. Not infrequently the artery lies in a small
canal on the deep surface of the bone, and in these cases a seg-
ment of the vessel will be removed along with the disc of bone.
The opening must then be enlarged in a downward direction
until the vessel is found leaving the canal, when its proximal
end can be ligated.

(b) The operation of Temporal Decompression is undertaken
to relieve the symptoms of headache and progressive loss of
vision, which result from increased intra-cranial pressure due
to cerebral tumours. The trephine is applied behind the Sylvian
point in order to avoid the anterior branch of the middle menin-
geal artery. The opening is enlarged in a downward and
backward direction till its diameter has been increased to from
2\ to 3 inches. While this enlargement is being carried out
the posterior division of the middle meningeal artery is exposed.
A crucial incision is made in the bulging dura mater after all
the vessels which are likely to be cut have been secured.

(c) The approach to the Semilunar (Gasserian) Ganglion is
described on p. 234.

(d) In order to evacuate an Abscess of the Temporal Lobe
a trephine opening is made at a point two inches above the ex-
ternal acoustic meatus. The skin incision begins in front of the
auricle, and is carried upwards and backwards above it and then
downwards behind it. After the membranes have been opened,
a director is passed medially into the brain at the point where
it bulges most. If the abscess is not located the director is
withdrawn, and then passed forwards and medially or back-
wards and medially until pus is found. Throughout the ex-
ploration the instrument should be kept parallel to the tegmen
tympani, and it must not be inserted for more than i£ inches
lest the inferior (descending) horn of the lateral ventricle be
entered. When Horsley's pus evacuator is used in place of a
director, it must be passed in closed, and it should be opened at
intervals of a quarter of an inch. In order to prevent severe

232 THE HEAD AND NECK

laceration of the brain, the instrument must be kept closed while
it is being inserted and withdrawn.

(e) In Ligature of the Posterior Division of the Middle
Meningeal Artery the skull is trephined at a point one inch above
and behind the external acoustic meatus. The skin incision is
planned so as to give good exposure of the area.

The Approach to the Anterior Cranial Fossa may be
made from in front or from the side. In the latter case the
approach resembles that to the middle fossa, but the trephine
is applied farther forwards and sufficiently high to preclude
the possibility of opening through the lateral wall of the orbit.

The operation is generally performed for abscess of the
frontal lobe, and it may be difficult to determine whether the
right or left side is involved. On this account the anterior route
may be preferred, as it enables the surgeon to expose the frontal
bone on both sides of the median line. The incision extends
from a little above the zygomatic (external angular) process of
the frontal bone on one side to a corresponding point on the
opposite side, and passes chiefly through the skin of the anterior
part of the scalp. In this way subsequent deformity due to
scarring may be avoided, and a large flap may be turned down-
wards. The trephine must be applied ij inches above the
superior margin of the orbit so as to avoid opening the frontal
air sinus. The subsequent procedure is very similar to that
described for the evacuation of an abscess in the temporal lobe.

During the moulding of the fatal head at birth, the parietal
bones may overlap one another to such an extent as to cause
rupture of the superficial cerebral veins near their union with
the superior sagittal sinus. The subdural haemorrhage which
ensues is usually localised to the motor centre for the lower
limb (p. 229), and it gives rise to an irritative condition of the
cortex and to symptoms of cerebral compression. Unless these
signs are recognised and operation resorted to within ten days
or a fortnight, irreparable damage may be done to the brain.
Neglected cases of this kind give rise to one of the varieties of
" birth palsy " — Little's disease. The haemorrhage may be
confined to one side only or it may be bilateral.

A curved incision, which is carried down to the bone, is
made over the area and the flap is turned down. The thin
superior border of the parietal bone is exposed and a blunt
dissector is passed under it. An osseous flap, similar in shape
to but slightly smaller than the flap of soft parts, is made with

THE BRAIN AND ITS MENINGES 233

scissors and the bone is broken across its base. A similar flap
of the dura mater is turned down, and the clot can then be
removed.

The Trigeminal or Fifth Cerebral Nerve possesses
a large (sensory) and a small (motor) root, both of which pierce
the serous layer of the dura mater near the apex of the petrous
portion of the temporal bone. The Semilunar (Gasserian)
Ganglion, which is situated on the large (sensory) root as it lies
on the petrous temporal, is enclosed between the serous and
fibrous layers of the dura mater. The Ophthalmic, Maxillary,
and Mandibular nerves arise from the anterior border of the
ganglion.

1. The Ophthalmic Nerve at once enters the lateral wall
of the cavernous sinus (p. 225) and is conducted to the orbit
(Fig. 63).

2. The Maxillary Nerve passes forwards to the foramen
rotundum and enters the upper part of the pterygo-palatine
(spheno-maxillary) fossa. Here it is connected to the spheno-
palatine (Meckel's) ganglion, which distributes sensory nerves
to the mucous membrane of the nose and palate. It then
reaches the infra-orbital groove, in the floor of the orbit, and,
after supplying the upper teeth, appears on the face as the
infra-orbital nerve (p. 172).

As it lies in the pterygo-palatine fossa, the nerve may be
reached by a needle passed medially from the surface. Advan-
tage is taken of this fact in tic douloureux to destroy the nerve
by injecting absolute alcohol or some other corrosive fluid into
its sheath. The needle is inserted 4 cm. in front of the external
acoustic meatus and immediately below the zygomatic arch.
As the coronoid process of the mandible may obstruct the
instrument or even break it, if the patient suddenly opens his
mouth during the operation, it is better to keep the mouth open
by means of a gag. The needle is then thrust medially through
the masseter, temporal, and external pterygoid muscles to a
depth of 5 cm. from the surface. If the point of the needle is
not obstructed, as it may be by the lateral pterygoid lamina
(external pterygoid plate) before it reaches this depth, it will
have passed through the pterygo-maxillary fissure into the
pterygo-palatine fossa. The contents of the syringe are injected
at this point, and, even although they do not actually pass into
the nerve sheath, the action of the destructive agent is sufficient
to destroy the nerve and its branches.

234 THE HEAD AND NECK

3. The Mandibular Nerve (p. 182) runs forwards and later-
ally for a short distance from the semilunar ganglion and then
passes downwards through the foramen ovale. At this point
it is joined by the whole of the small (motor) root, which lies
on the bone below the semilunar ganglion.

Removal of the Semilunar (Gasserian) Ganglion.—
The approach in this operation and in ligature of the main trunk
of the middle meningeal artery is similar to that described on
p. 230, but a somewhat wider exposure is necessary. In order
that this may be obtained; the temporal fascia is incised along
the upper border of the zygomatic arch and the bone is divided
at each end. When this is done the arch can be depressed
for half an inch; and the temporal muscle is retracted into the
interval between it and the skull. A trephine can now be
applied a little above the level of the floor of the middle cranial
fossa — which corresponds to the upper border of the undivided
arch — and sufficiently far forwards to avoid the main trunk of
the middle meningeal artery. In this region the thickness of
the skull varies, being much greater below than above ; and this
difference must be borne in mind, as otherwise the blade of the
trephine may tear through the dura mater above, before it has
pierced the bone below. After the circular piece of bone has
been removed, the trephine opening is enlarged and the middle
meningeal artery is exposed and traced medially to the foramen
spinosum, where it is ligated and divided. Before the ligature
can be applied, the dura mater must be elevated from the floor
of the fossa by blunt dissection, and, after the artery has been
dealt with, this is continued until the lateral margin of the
ganglion is reached. At this point the fibrous and serous layers
separate to enclose the ganglion, and the elevation of the fibrous
layer becomes more difficult. The surgeon endeavours to incise
or break through the fibrous layer just beyond the splitting. If
this is done successfully, the maxillary nerve is exposed running
forwards to the foramen rotundum. If, however, the dura
mater is incised before the two layers separate, the subdural
space is opened, and the fluid which it contains floods the area
and greatly increases the difficulty of the operation. By
tracing the maxillary nerve backwards, the mandibular nerve
is exposed a little in front of and medial to the ligated middle
meningeal artery, and more posteriorly still the ganglion is
reached. If the serous layer of the dura is elevated in a medial
direction, the ophthalmic nerve will be found lying in the lower

THE BRAIN AND ITS MENINGES 235

part of the lateral wall of the cavernous sinus (p. 225). The
large (sensory) root is exposed by stripping the serous layer of
the dura mater backwards off the ganglion, and it is then divided.
The maxillary and mandibular nerves are cut through as far
away from their origin as possible, and the ganglion is then torn
out along with the ophthalmic nerve. As the latter lies in
contact with the thin endothelial wall of the cavernous sinus
and is closely related to the internal carotid artery and the
third, fourth, and sixth cerebral nerves (p. 225), few operators
attempt to divide it with the knife. As soon as the ganglion is
torn out severe hsemorrhage occurs, owing to the unavoidable
laceration of the wall of the cavernous sinus, but it is readily
controlled by pressure. It is seldom found possible to preserve
the small (motor) root, and, following the operation, the muscles
of mastication are paralysed on that side. In this condition
the mandible is permanently twisted over to the side of the lesion
by the unopposed action of the pterygoid muscles of the opposite
side (p. 181). Another common sequela is thrombosis of the
cavernous sinus with consequent proptosis, chemosis, and retinal
haemorrhage. Temporary blindness or permanent impairment of
vision may result, and there is usually some temporary paralysis
of the ocular muscles. The results of the alteration in the
sensibility of the conjunctiva are described on p. 204.

Contents of the Posterior Cranial Fossa. — The
Medulla Oblongata is the direct continuation of the spinal
medulla, and is continuous above with the Pons. Ventrally,
these two structures lie on the basilar portions of the occipital
and sphenoid bones ; dorsally, they are related to the cere-
bellum, which also overlaps them laterally. In the medulla
oblongata and the pons the central canal of the spinal medulla
expands to form the fourth ventricle, and the floor of this space
contains the important respiratory and cardiac centres.

On each side the transverse fibres of the pons pass into the
cerebellum as the brachium pontis (middle peduncle), and the
region where the lower part of the brachium enters the cere-
bellum is known as the cerebello-p online angle. In this region
the facial and auditory nerves emerge at the lower border of
the pons. At its upper extremity the pons becomes con-
tinuous with the mid-brain, which sinks into the basal surface
of the cerebral hemispheres.

Tumours in the region of the cerebello-pontine angle usually
involve the seventh and eighth cerebral nerves. They may

236 THE HEAD AND NECK

be approached by the route described on p. 227 for the
reopening of the foramen of Magendie. The operation is
commonly performed in two stages, the first of which ceases
after the complete removal of the lower part of the squamous
portion of the occipital bone. In the second operation the occipi-
tal sinus is ligatured and divided along with the falx cerebelli
(p. 225). The cerebellum is displaced to the opposite side,
care being taken not to press it against the floor of the fourth
ventricle, and access is thus obtained to the cerebello-pontine
angle.

THE ABDOMINAL WALLS 237

THE ABDOMEN AND PELVIS.

THE ABDOMINAL WALLS.

Surface Landmarks.— The Costal Margins, formed by the
cartilages of the tenth, ninth, eighth, and seventh ribs (the
last named being the lowest pair to reach the sternum), pass
upwards and medially towards the sides of the xiphoid process
and enclose between them the Subcostal Angle. The xiphoid
process lies in the depression at the apex of this angle, and its
pointed lower end is sometimes bent forwards, being then easily
palpable beneath the skin.

The Iliac Crest forms the lower limit of the lateral aspect of
the abdominal wall. It can be traced forwards to the Anterior
Superior Spine, which lies on the same level as the second sacral
vertebra. About 2 inches behind this point, a prominent
tubercle can be felt on the outer lip of the crest ; it is utilised
in mapping out the regions of the abdomen.

The fold of the groin extends downwards and medially from
the anterior superior spine to the tubercle (spine) of the pubis.
It overlies the inguinal ligament (of Poupart), which is slightly
convex downwards owing to the traction exerted on it by the
fascia lata of the thigh. This traction is transmitted by the
ligament to the lateral abdominal muscles, which are attached
to it, and renders them slightly tense when the thighs are
extended. In the examination of the abdomen, it is ad-
vantageous that the muscles should be relaxed as far as
possible, and to overcome the traction of the fascia lata, the
patient's legs are drawn up, flexing both the hip and the knee-
joints. This is the posture which is naturally assumed when
there is much distension of the abdomen, since it allows the
maximum amount of relaxation of the abdominal parietes.

The highest point on the iliac crest lies on a level with the
lower part of the body of the fourth lumbar vertebra. In
subjects with firm abdominal muscles, the umbilicus also
corresponds to this level, but in obese subjects with lax ab-
dominal parietes, it may sink down to a lower plane.

A linear furrow can be seen, in muscular subjects, in the
middle line of the anterior abdominal wall. It corresponds to

238

THE ABDOMEN AND PELVIS

the Linea Alba (p. 247), a tendinous raphe which separates the
two recti muscles. It widens out somewhat above the umbilicus,

FIG. 71. — Surface Landmarks of the Anterior Abdominal Wall, showing
the lines of some of the commoner incisions.

1. Cholecystotomy incision.

2. Intussusception incision.

3. Pelvic ureterotomy incision.

4. Supra-pubic cystotomy incision.

5. Lumbo - ilio - inguinal incision, lower

part.

but below that level it is difficult to recognise. In multiparae,
however, and in children suffering from rickets, the two recti are
often definitely separated below the umbilicus, so that the
finger tips may be introduced between them.

The lateral margin of the rectus muscle is indicated on the

THE ABDOMINAL WALLS 239

surface by a curved furrow — the linea semilunaris. It com-
mences below at the pubic tubercle and passes midway between
the umbilicus and the anterior superior iliac spine. It then
runs upwards and slightly medially, crossing the costal margin
near the tip of the ninth costal cartilage. Transverse furrows
may sometimes be seen crossing the upper part of the rectus.
They correspond to the lineae transversse (p. 246).

The posterior superior iliac spine may be found by tracing
the iliac crest backwards. Its situation is marked by a dimple,
which lies i| inches from the middle line. It is placed opposite
the middle of the sacro-iliac joint and on a level with the second
sacral spine.

The spines of the lumbar vertebrae lie at the bottom of the
spinal furrow, but they are rendered visible when the trunk is
flexed. On each side of the furrow is the prominence due to
the sacro-spinalis (erector spincz) muscle, the lateral margin of
which can be felt, and sometimes seen, at a distance of 3^ inches
from the middle line. The tip of the twelfth rib can be recognised
as it emerges from under cover of this border. It lies about
two inches above the midpoint of the iliac crest, but it must be
remembered that the lowest palpable rib is not necessarily the
twelfth, which is often rudimentary and completely hidden by
the sacro-spinalis.

The Subcutaneous Inguinal Ring (Ext. Abdom. Ring),
through which the spermatic cord leaves the inguinal canal,
lies immediately above the pubic tubercle (spine) and may
be examined by invaginating the skin of the scrotum from
below. The anterior surface of the pubis is palpated, and the
finger is carried upwards until the pubic crest is reached. It is
then pressed backwards into the anterior abdominal wall, and
can be felt to pass into a yielding gap, which possesses sharp
and definite margins — the subcutaneous inguinal ring. If the
finger is carried upwards, after reaching the upper border of
the pubis, it can be moved about quite freely under the skin
and fasciae of the anterior abdominal wall.

To aid topographical description, the abdomen is subdivided into regions
by two transverse and two vertical planes, (a) The Subcostal Plane passes
horizontally through the body at the level of the most dependent parts of the
tenth costal cartilages ; it lies on a level with the upper part of the third
lumbar vertebra, (ti) The Intertubercular Plane passes horizontally through
the tubercles of the iliac crests ; it corresponds in level with the upper part of
the fifth lumbar vertebra, (c) The Right and (d) the Left Lateral Planes
are at right angles to the transverse planes, and each bisects the line joining
the anterior superior iliac spine to the symphysis pubis.

240 THE ABDOMEN AND PELVIS

In this way nine regions are mapped out on the surface. The three
median areas are named, from above downwards, the epigastric, umbilical,
and hypogaslric regions ; the six lateral areas are, the right and left hypo-
chondriac, lumbar, and iliac regions, in that order from above downwards.

In addition to the above,, the Transpyloric Plane is
exceedingly useful. It is a transverse plane, which passes
horizontally through the mid-point of the line joining the
jugular (suprasternal) notch to the symphysis pubis, and it
crosses the linea semilunaris at the costal margin (tip of the
ninth costal cartilage). Posteriorly, it corresponds in level with
the lower part of the body of the first lumbar vertebra.

The Superficial Fascia in the upper part of the anterior
abdominal wall is directly continuous with the corresponding
layer of the thoracic wall. Below it consists of (i) a superficial
fatty stratum, known as Camper's fascia, which is continuous
with the superficial fascia of the thigh, and (2) a deeper
membranous layer, which is in direct contact with the aponeurosis
of the external oblique muscle, no deep fascia intervening.
The latter is known as Scarpa's fascia. It descends on each
side in front of the inguinal ligament, and blends with the fascia
lata of the thigh immediately below and nearly parallel to that
structure. In the middle line it is carried down in front of the
pubic bones and becomes continuous with the fascia of Colles,
which invests the penis and scrotum, and forms the roof of the
superficial perineal pouch (p. 376). In cases of extravasation
of urine or of severe haemorrhage into the pouch (p. 376), the
lines of attachment of this fascia are accurately demonstrated.

Superficial Nerves. — The skin of the anterior abdominal
wall is supplied by the anterior cutaneous branches of the lower
six thoracic said first lumbar nerves. The tenth thoracic supplies
the skin in the neighbourhood of the umbilicus. The ilio-
hypogastric and ilio-inguinal nerves are both derived from L. i ;
the latter reaches the surface at a lower level than the f ormej, and
supplies the skin over the tubercle (spine) of the pubis, the upper
part of the scrotum, and the proximo-medial part of the thigh.

On the lateral aspect of the abdominal wall the skin is supplied
by the lateral cutaneous branches of the seventh-eleventh
thoracic nerves. Corresponding branches from the twelfth
thoracic and ilio-hypogastric descend over the iliac crest to
supply the skin of the gluteal region.

The anterior rami (ant. prim, divisions), which give off
these various branches, descend obliquely as they pass round

FIG. 72. — The Nerve-Supply of the Skin on the Ventral Aspect of the Trunk.
The whole of the area shown in the diagram is supplied by branches
from the anterior rami (primary division) of the spinal nerves.

G.A, Great auricular nerve; S.C, N. cutaneus colli ; S.Ci., Supra-clavicular nerves;
ACR, Posterior; ST, Middle; CL, anterior; T.2-I2, Lateral and anterior branches
of thoracic nerves; I.H, Ilio-hypogastric nerve; I.I, Ilio-inguinal nerve; CIRC,
Cutaneous branch of axillary nerve ; L. I.C, Medial cutaneous nerve of the arm (O.T.
lesser internal cutaneous nerve); I.H, Intercosto-brachial ; I.C, Medial cutaneous
nerve of the forearm (O.T. internal cutaneous); M.S, Cutaneous branch of radial
nerve ; E.C, Lateral cutaneous nerves; G.C, Lumbo-inguinal nerve; M.C1 2, Inter-
mediate cutaneous nerves ; I.C1, Branch of medial cutaneous nerve ; P, Branches of
pudendal nerve ; S.Sc, Branches of posterior cutaneous nerve of the thigh.

On the other side a schematic representation is given of the areas supplied by the above
nerves, the numerals indicating the spinal origin of the branches of distribution to
each area.

241

16

242 THE ABDOMEN AND PELVIS

the abdominal wall. Their obliquity can be appreciated if the
course of the eighth intercostal nerve is examined. Posteriorly,
it is placed at the level of the inferior angle of the scapula, but
anteriorly it ends midway between the xiphoid process and the
umbilicus. The lateral cutaneous branches descend under cover
of the fascia before they come to the surface, and so, despite the
oblique course of the main trunks, the terminal branches supply
areas of skin, which are almost horizontal (Fig. 72).

The skin of the posterior abdominal wall is supplied by the
posterior rami (primary divisions) of the lower thoracic and upper
lumbar nerves (L. i, 2, and 3). (Fig. 3).

These incline downwards in the fascia, and become cutaneous
on the same horizontal plane as the lateral and anterior branches.

In Herpes Zoster the affected areas do not map out the
course of a thoracic nerve, but the terminations of its cutaneous
branches. They therefore form horizontal strips round the
body, and they correspond exactly to the areas in which the
" girdle pains " are experienced in locomotor ataxia.

Referred Pain. — The anterior rami (ant. prim, divisions)
of the thoracic and of the first (and sometimes second)
lumbar nerves are connected to the corresponding ganglia of
the sympathetic by both white and grey rami communicantes
(p. 125). The nerve-supply to the abdominal viscera is derived
from the lower eight thoracic and the first lumbar segments
and, consequently, afferent impulses from the viscera reach
the same segments in the spinal medulla (cord) as do the afferent
impulses from the skin of the abdominal wall. In pathological
conditions the afferent impulses from the viscera may become
so altered, either in strength or character, as to overflow those
cells for which they were originally intended, and stimulate
those neighbouring cells which are accustomed to receive
impulses from the skin of the abdominal wall (Fig. 73). When
the stimuli from these latter cells reach the brain, they are
interpreted as painful sensations affecting the skin area supplied
by the segment of the spinal medulla which is involved. Pain
of this variety, which may be felt in a different region from the
viscus at fault, is spoken of as referred pain, and the whole reflex
is called the " viscero- sensory reflex" (Mackenzie). The areas
in which referred pain may be felt in pathological conditions of
the various viscera are dealt with under each individual organ
(pp. 298, 312, etc.).

The Superficial Veins of the abdominal wall may be divided

THE ABDOMINAL WALLS

243

into an upper and a lower group. The upper veins join the
internal mammary, intercostal, and lateral (long) thoracic veins,
and so return their blood to the heart via the vena cava superior.
The lower veins join the femoral, and consequently drain into
the vena cava inferior. These two groups communicate freely
with one another through the thoraco-epigastric vein, which
ascends from the groin to the region of the axilla. Owing to
their position these veins are capable of considerable increase
in size. In obstruction of the vena cava inferior this anastomosis

Cerebral cortex in
connection with skin

Cerebral cortex
in connection
with viscus

Cells in anterior column of
spinal medulla

FIG. 73. — Diagram to illustrate the Viscero - Sensory and Viscero-Motor
Reflexes. The arrows indicate the passage of the afferent impulses from
the viscus to the cortex, and show how they may overflow so as to
stimulate the neighbouring cells in the spinal medulla.

provides a new channel for the return of blood from the lower
limbs, and the thoraco-epigastric vein becomes specially enlarged.
Further, the para-umbilical vein (of Sappey) passes from the left
branch of the portal vein along the ligamentum teres to the
umbilicus, where it communicates with both groups. Varicosity
of the superficial abdominal veins may therefore occur in
portal obstruction, but in this case the blood -flow in the
distended veins is from the umbilicus both upwards and down-
wards, whereas in obstruction of the vena cava inferior the
blood-flow is in an upward direction only.

The Lymph Vessels of the whole abdominal wall, below
the level of the umbilicus, join the superficial sub-inguinal lymph

244 THE ABDOMEN AND PELVIS

glands (p. 400). Above the umbilicus, those from the anterior ab-
dominal wall join the pectoral glands,, while those from the pos-
terior abdominal wall terminate in the subscapular group (p. 35).

Lymph vessels from the liver descend along the ligamentum
teres to the umbilicus, where they establish communications
with the lymphatics of the anterior abdominal wall. Cancer of
the umbilicus may occur secondarily to cancer of the liver, and
the infection may spread to the lymph-glands in the groin.

Lateral and Anterior Muscles of the Abdominal
Wall. — The external oblique muscle arises from the lower
eight ribs, and its fibres are mainly directed downwards, forwards,
and medially. Above, it interdigitates with the serratus anterior
(serr. magnus), and the deep fascia which covers both muscles
forms a continuous sheet (p. 31). The lowermost (or posterior)
fibres run vertically downwards, and are inserted into the
anterior half of the iliac crest, so that between the last rib and
the crest the external oblique has a free posterior border, which
forms the lateral boundary of the lumbar triangle (of Petit).
The remaining fibres become aponeurotic near the linea semi-
lunaris, and pass in front of the rectus abdominis to reach
the xiphoid process, linea alba, pubic symphysis, and crest.
No muscular fibres are found below a line joining the anterior
superior spine of the ilium to the umbilicus.

The lower border of the aponeurosis of the external oblique
forms the inguinal ligament (of Poupart), which extends from
the anterior superior spine to the pubic tubercle (spine). It is
bent upwards and backwards on itself so that the upper surface
of the ligament is grooved. The lacunar ligament (of Gimbernat)
is the medial part of the folded-back margin of the inguinal
ligament. It is attached to the pecten pubis (ilio-pectineal line)
and possesses a free, crescentic, lateral margin, which is intimately
related to the femoral (crural) ring (p. 403).

Just above the medial end of the inguinal ligament the
spermatic cord pierces the aponeurosis of the external oblique,
and the opening through which it passes is known as the
subcutaneous inguinal (ext. abdom.) ring (pp. 239 and 254).

The Internal Oblique lies under cover of the preceding
muscle. It arises from the lumbo- dorsal fascia (p. 269),
through which it gains attachment to the lumbar spines, so that
it possesses no free posterior border — the iliac crest, and the
lateral two -thirds of the inguinal ligament. The general
direction of the fibres is upwards, forwards, and medially.

THE ABDOMINAL WALLS

245

The uppermost fibres are inserted into the lower ribs and their
cartilages ; the intermediate fibres form an aponeurosis, which is
inserted into the linea alba ; the lowest fibres arch over the
spermatic cord and are inserted behind it as it leaves the inguinal

Greater occipital nerve

Third occipital nerve

Sterno-mastoid

Lesser occipital nerve

Trapezius

Deltoid

Semispinalis capitis (O.T. complexus)

Splenius capitis
Cervical nerves to trapezius
Accessory nerve

Ascending br. of transverse cervic
Levator scapulae

Descending br. of t
cervical artery and
scapulas nerve

Rhomboideus rr

_ Trapezius
(reflected)

Rhomboideus
major

Teres major

Serratus ante

Serratus posterior inferior
Latissimus dorsi
External oblique muscle
Trigonum lumbale (Petiti)

Glutseus medius
Glutseus maximus

FIG. 74. — The Muscles on the Dorsal Aspect of the Trunk.

canal. The latter blend with fibres of the transversus to form
the Falx Inguinalis Aponeurotica (Conjoined Tendon).

The Transversus Abdominis is the deepest muscular layer
of the lateral abdominal wall. It arises (i) from the internal
surfaces of the lower six costal cartilages, interdigitating with
the diaphragm, so that the fascia on its deep surface

16 a

External divisions of
posterior rami of —
lumbar nerves

246 THE ABDOMEN AND PELVIS

(f. transversalis) is continuous with the layer on the under
surface of the diaphragm ; (2) from the lumbo-dorsal fascia ;
and (3) from the iliac crest and the lateral third of the inguinal
ligament. The general direction of the fibres is horizontal, but
the lowest fibres turn downwards to be inserted into the pecten
pubis (ilio-pectineal line) where they take part in the formation
of the falx inguinalis (conjoined tendon). The rest of the muscle
forms an aponeurosis which gains attachment to the linea alba.
This aponeurosis is extremely narrow above, but it gradually
widens below.

The Eectus Abdominis muscle arises from the pubis and
extends upwards in the interval between the linea alba and the
linea semilunaris (p. 239). It is inserted into the anterior
aspects of the fifth, sixth, and seventh costal cartilages. Irregular
tendinous intersections cross the muscle, one at the umbilicus,
a second at the xiphoid process, and a third midway between
the other two. They are known as the Linece Transverse? , and
are strongly adherent to the anterior wall of the rectus sheath.

The sheath of the rectus abdominis is a strong but incomplete
aponeurotic envelope, which is formed by the aponeuroses of the
three lateral abdominal muscles. It is differently constituted
in its upper and lower parts.

(a) Above the level of the midpoint between the umbilicus and
the symphysis pubis. — The aponeurosis of the internal oblique
splits into an anterior and a posterior lamella at the lateral
margin of the rectus. The anterior layer blends with the
aponeurosis of the external oblique, and forms the anterior wall
of the sheath, while the posterior layer blends with the aponeurosis
of the transversus to form the posterior wall. Where the
muscle rests on the costal cartilages near its insertion, the
posterior wall of its sheath is deficient, as the internal oblique
and transversus abdominis do not pass upwards beyond the
seventh costal cartilage. In its upper part the posterior wall
is not entirely aponeurotic, as, owing to the narrowness of its
aponeurosis, the upper fleshy fibres of the transversus lie behind
the rectus abdominis and almost reach the linea alba.

(b) Below the level of the midpoint between the umbilicus and
symphysis pubis. — In this region the sheath of the rectus is
formed anteriorly by the blended aponeuroses of the external
oblique, internal oblique, and transversus. The posterior wall
terminates in a free crescentic lower margin — the linea semi-
circularis (semilunar fold of Douglas) — at the level indicated

THE ABDOMINAL WALLS

247

above. This margin is usually fused with the underlying trans-
versalis fascia, which is in direct contact with the rectus ab-
dominis in the lower part of the abdominal wall.

Little difficulty is experienced in freeing the rectus abdominis
from the posterior wall of the sheath, but the muscle is much
more firmly adherent to the anterior wall, especially opposite
the lineae transversse.

FIG. 75. — Diagram of Transverse Sections through the Rectus Abdominis
Muscles, to illustrate the method of closing wounds in the infra-umbilical
part of the linea alba.

I. The dotted line indicates the incision in the linea alba.

II. Prior to closure of the median wound, an incision has been made on each side
into the anterior wall of the sheath.

III. Closure of the median wound. The deepest suture includes the cut edges of the
parietal peritoneum as well as the sheath. The two recti and the anterior walls of their
sheaths may be united by one continuous suture and not by two layers of sutures as
shown in the figure.

Incisions in the Abdominal Wall.— Vertical Incisions
through the linea alba have several advantages, (i) They
are almost bloodless. (2) No muscle fibres are cut across. (3)
No nerves are injured. (4) They give access to both sides of
the abdomen.

When the linea alba and the subjacent fascia transversalis
have been incised, the extra-peritoneal fat is exposed. This is
a thin layer inferiorly, but it is much thicker above the umbilicus.

Owing to the close approximation of the recti below the
umbilicus there is very little tendency for ventral hernia to occur
after incisions through the lower part of the linea alba, but
vertical incisions through the supra-umbilical part of this line

248 THE ABDOMEN AND PELVIS

tend to leave a weakness in the anterior abdominal wall when
they heal. This is due to the normally existing interval between
the upper portions of the two recti muscles, and maybe prevented
in the following way. A vertical incision, the length of the
original wound, is made through the anterior wall of each rectus
sheath along its medial border, and the medial edges of these
cuts are stitched together (Fig. 75) by sutures which also pass
through the peritoneum. In this way the gap is bridged by
strong tissue which is not too tightly stretched. The medial
edges of the recti and the anterior layers of their sheaths are
stitched together over the newly-formed deep layer of the
abdominal wall (Stiles).

The same method may be adopted in the radical cure of a
ventral hernia in this region.

The "Gridiron Incision" is planned so as to minimise,
as far as possible, the subsequent weakness in the abdominal
wall. The fibres of the various muscles are not cut across but
are separated in the direction in which they run. It is most
frequently employed in inguinal colotomy and in the oblique ap-
proach to the vermiform process (appendix) over M'Burney's point
(which lies at the junction of the middle and lower thirds of the
line joining the umbilicus to the anterior superior iliac spine).

The skin and fascia are divided downwards and medially,
exposing the glistening aponeurosis of the external oblique,
and in the upper part of the wound some of its muscular fibres.
The aponeurosis is split in the line of the incision, i.e. parallel
to the direction of the muscular fibres, and the split is continued
upwards into the fleshy part of the muscle. When the cut
edges are retracted, the lower part of the internal oblique is
exposed. In this region the fibres of both the internal oblique
and the transversus abdominis (transversalis) are practically
horizontal, but in the lower part of the wound they turn
downwards to form the falx inguinalis (conjoined tendon). These
two parts of both muscles are separated from one another along
a horizontal line at the level of the anterior superior spine. The
fascia transversalis, which is now exposed, and the underlying
peritoneum are opened at the same time, but great care must
be exercised, as the bowel may be adherent to the latter.

If the muscular interval, obtained in this way, does not give
sufficient access, the split may be extended both laterally and
medially. In the former direction it may be carried to the
anterior superior spine, exposing the ascending branch of the

THE ABDOMINAL WALLS

249

circumflex iliac artery (p. 253) ; in the latter, it is continued
along the same horizontal line through the anterior wall of

Transpyloric
plane

Right later
plar

Xiphoid process

FIG. 76. — Surface Landmarks of the Anterior Abdominal Wall, showing
the lines of some of the commoner incisions.

5. Infra-umbilical median incision.

1. Exposure of gall-bladder.

2. Supra-umbilical median incision

3. Gastrostomy incision.

4. Gridiron incision.

6. Colostomy incision (through rectus).

7. Colostomy incision.

8. Exposure of spleen and left colic flexure.

the rectus sheath. The muscle is retracted medially, and the
posterior wall of the sheath is similarly divided, care being taken
to avoid or to ligate the inferior (deep) epigastric artery (p. 253).
The abdomen may also be opened through the rectus
sheath. In the upper third, this route gives access to the

250 THE ABDOMEN AND PELVIS

gall-bladder through the right rectus, and to the stomach
through the left rectus. The direction of the incision may
vary as it passes through the skin and fascia, but the anterior
layer of the sheath and the muscle are split vertically, i.e.
parallel to the muscular fibres, or the rectus may be freed and
retracted. Finally, the posterior layer of the sheath and the
muscular fibres of the trans versus (p. 246) are divided, together
with the subjacent and partially adherent fascia trans versalis.
This exposes the extra-peritoneal fat, which forms a layer of
considerable thickness in this region. After it has been cut
through, the parietal peritoneum becomes visible.

In the lower third, this route may be employed for
appendicectomy. As soon as the rectus is split or retracted,
the fascia transversalis is exposed, as the posterior wall of the
sheath is deficient in this region (p. 246). The inferior (deep)
epigastric artery, which lies on the fascia transversalis (p. 253),
is also exposed, and it may either be retracted or ligated. The
extra-peritoneal fat is very scanty, and may only be represented
by a little areolar tissue.

Occasionally, e.g. for the removal of large tumours of the
kidney or malignant growths of the colon, it may be necessary
to cut through the lateral abdominal muscles in a vertical
direction ; i.e. across the muscular fibres. The incision com-
mences above at the lower border of the tenth costal cartilage,
and descends towards the anterior superior iliac spine. Below,
it passes medially, above the inguinal ligament. It penetrates
all the muscles of the abdominal wall along the same line and
is limited, medially, by the inferior (deep) epigastric artery and
the abdominal inguinal (int. abd.) ring.

The Nerves of the Abdominal Wall run in the interval
between the internal oblique and the transversus abdominis —
the upper, horizontally ; the lower, downwards and medially.
After they leave the costal margin, the seventh and eighth
intercostal nerves run upwards and medially behind the rectus,
while the ninth and tenth run transversely. The nerves of the
abdominal wall include the lower seven thoracic nerves and the
first lumbar nerve, which is represented by two branches, the
ilio-hypogastric and the ilio-inguinal. As they pass forwards
they supply the lateral muscles of the abdominal wall, and at
the linea semilunaris all, save the ilio-hypogastric and ilio-
inguinal, enter the rectus sheath. Finally they supply the
rectus muscle, and pierce it to become cutaneous (p. 240).

THE ABDOMINAL WALLS 251

Their nerve - supply indicates that the muscles of the
abdominal wall have arisen from the fusion of the muscles of
six or seven adjoining segments, which were originally quite
independent. In consequence of its segmental character the
rectus abdominis may be cut across in operations and reunited
with much less functional loss than results from section of
muscles which have not arisen in this way (e.g. biceps brachii).
In addition, one or more adjoining segments may become
contracted, while the rest of the muscle is relaxed. Such
localised areas of contraction may be due to cramp, but they
are frequently found in connection with pathological conditions
of the abdominal (p. 354) or even thoracic viscera. These
cases are examples of the " viscero-motor reflex " (Mackenzie).
The afferent impulses from the viscus at fault to the central
nervous system not only set up the viscero-sensory reflex
(p. 242) but they may also " overflow " into the motor cells of
the anterior column (horn) of the grey matter. The efferent
fibres of these cells supply the corresponding muscle segment,
and in this way the localised contracted areas may be explained

(Kg. 73).

In making incisions through the abdominal wall it is
important that the position and course of the nerves should
be borne in mind, for although one may be injured without any
undesirable after-effects, the abdominal wall never completely
recovers its muscular tone after section of the motor nerves.
For this reason, when possible, the incisions are planned so as
to avoid injuring the nerves, e.g. the median and gridiron
incisions. In opening the abdomen through the rectus abdominis
the muscle should, when possible, be retracted to the lateral
side for the same reason.

A large rectangular incision is employed by Perthes in
order to expose the region of the gall-bladder and the bile-duct.
The vertical limb begins a little below the xiphoid process, and
descends one finger's breadth to the right of the median plane,
almost to the umbilicus. The horizontal limb passes to the
right from the lower end of the vertical limb. The anterior wall
of the rectus sheath is divided in the line of the vertical part of
the incision, and the medial border of the muscle is defined.
The finger can then be inserted behind the rectus so as to
separate it from the posterior wall of its sheath.

Two transverse rows of sutures are passed through the
anterior wall of the sheath and through the muscle, in the line

252 THE ABDOMEN AND PELVIS

of the horizontal part of the incision. When this has been done,
the anterior wall of the sheath and the rectus may be cut across
between the two rows of sutures, which serve to prevent
retraction of the cut ends of the muscle A large triangular
musculo-cutaneous flap can then be turned upwards and to
the right, until the terminal parts of the intercostal nerves are
exposed as they pass forwards into the rectus. The posterior
wall of the sheath, together with the underlying transversalis
fascia and parietal peritoneum, is divided by an oblique incision,
which is placed medial to the nerves and nearly parallel to the
costal margin.

This method of approach, while providing good access to
the region of the gall-bladder, produces little weakening of the
abdominal wall, since none of the motor nerves are injured. In
addition there is little danger of the occurrence of a post-operative
hernia, as the anterior and posterior walls of the rectus sheath are
not divided in the same line.

An incision, of varying length, two inches below and
parallel to the right costal margin, gives good access to the
gall-bladder. In obese subjects it may be necessary to prolong
the lateral part of the incision in a downward direction. If,
during this operation, the lower part of the patient's back is
supported by a sand-bag, pillow, etc., the forward convexity of
the lumbar region is increased, the viscera are pressed forwards,
and the wound gapes so as to afford excellent access. Incisions
planned to preserve the nerves, i.e. made at right angles to the
costal margin, cannot be made to gape in the same way.

In all cases where the abdominal muscles are cut across the
direction of their fibres, the wall must be sewn up in layers to
diminish the subsequent weakness as far as possible.

The Transversalis Fascia covers the deep surface of the
transversus muscle, and, inferiorly, it extends beyond the lower
border of the muscle to reach the inguinal ligament. It extends
medially behind the posterior wall of the rectus sheath, with
which it partially blends. In the lower part of the anterior
abdominal wall, where the rectus sheath is deficient posteriorly,
the transversalis fascia lies in direct contact with the rectus
abdominis. Above, it is continuous with the fascia on the under
surface of the diaphragm, and below with the pelvic fascia.
The connections of the transversalis fascia on the posterior
abdominal wall are described on p. 271.

Arteries of the Anterior Abdominal Wall. —

THE ABDOMINAL WALLS 253

(a) SUPERFICIAL. — The arteries which supply the lower
part of the wall are all derived from the femoral, and ascend
from the thigh, (i) The Superficial Epigastric crosses the
middle of the inguinal ligament. (2) The Superficial External
Pudendal runs medially across the spermatic cord. Both of
these vessels are usually divided in the incisions for inguinal
hernia. (3) The Superficial Circumflex Iliac supplies the
skin in the neighbourhood of the anterior superior iliac spine.

(b) DEEP.— i. The Inferior (Deep) Epigastric artery arises
from the external iliac, just above the inguinal ligament, and
ascends in the direction of the umbilicus. At first it lies in the
extra-peritoneal fat, but it soon pierces the fascia transversalis,
and enters the rectus sheath by passing in front of the linea
semicircularis (semilunar fold of Douglas). It then runs
upwards on the deep surface of the rectus and anastomoses
with the superior epigastric, which is descending from the
internal mammary.

The inferior epigastric artery may be injured if the oblique
appendicular wound (p. 248) is increased downwards and
medially, or when the rectus is split longitudinally.

The origin of the inferior epigastric lies half an inch above
the inguinal ligament, and midway between the anterior superior
iliac spine and the symphysis pubis. Its course may be indicated
by a line drawn from its point of origin towards the umbilicus.

The important relations of this vessel to the inguinal canal
and to the varieties of inguinal hernia are described on pp. 255
and 263.

2. The Deep Circumflex Iliac artery also arises from the
external iliac, just above the inguinal ligament. It passes
upwards and laterally along the inguinal ligament and the
iliac crest. Just behind the anterior superior spine it gives off
a moderately large branch, which ascends between the internal
oblique and transversus, and may be injured when the gridiron
appendicular incision is prolonged laterally.

The Inguinal Region. — The Inguinal Canal is an oblique
cleft in the anterior abdominal wall above the medial half of
the inguinal ligament. In the male it contains the spermatic
cord, and this structure enters the canal at its upper end through
the Abdominal Inguinal (Int. Abd.) Ring, which is situated in
the fascia transversalis about half an inch above the inguinal
ligament, midway between the anterior superior iliac spine and
the pubic symphysis. The canal is about one and a half inches

254 THE ABDOMEN AND PELVIS

long, and extends downwards,, forwards, and medially to the
Subcutaneous Inguinal (Ext. Abd.) Ring, where the spermatic
cord emerges from the abdominal wall. The subcutaneous
inguinal ring is a triangular opening situated in the external
oblique aponeurosis. Its base is formed by the lateral part
of the pubic crest, and its apex is directed upwards and laterally.
The upper (or medial) and lower (or lateral) margins of the
opening, known as the Crura or Pillars., are formed by the
external oblique aponeurosis.

The upper or deep end of the canal is therefore placed
lateral to the lower or superficial end. This arrangement
greatly diminishes the weakness produced in the anterior
abdominal wall by the passage through it of the spermatic cord,
for when the viscera are pressed against the abdominal inguinal
(int. abd.) ring, e.g. in coughing, they are at the same time
pressed against the posterior wall of the canal, which they force
into apposition with its anterior wall. In this way the canal is
practically closed.

The Anterior Wall of the inguinal canal is formed by the
aponeurosis of the external oblique ; in addition, those fibres of
the internal oblique which arise from the middle of the inguinal
ligament assist in its formation in the lateral third of the canal.

In order to expose the spermatic cord as it lies in the inguinal
canal, it is necessary to cut through the external oblique
aponeurosis from the lower crus (pillar) of the subcutaneous
inguinal ring for ij inches, parallel to the inguinal ligament.
Medially, this incision exposes the cord, but laterally the cord
is still covered by the lowest fibres of the internal oblique, and
when they are divided the canal is laid open in its whole length.

The Posterior Wall of the inguinal canal is formed by the
fascia transversalis ; medially, however, it is strengthened by
the falx inguinalis (conjoined tendon), which lies in front of the
transversalis fascia, but behind the cord (Fig. 77).

The lowest fibres of the transversus abdominis lie above the
level of the lateral part of the canal, and in consequence its
fleshy fibres take no part in the formation of the posterior wall.
Its place is taken by the fascia transversalis, which descends
beyond the lower border of the muscle to reach the inguinal
ligament. The lower fibres of the internal oblique are placed,
at their origin, in front of the spermatic cord, but as they pass
medially they arch over it — forming the Roof of the canal — and
then descend behind it in the falx inguinalis (conjoined tendon).

THE ABDOMINAL WALLS 255

The weakest part of the posterior wall of the canal (the
abdominal inguinal ring) is placed opposite the strongest part
of the anterior wall ; similarly, the weakest part of the anterior
wall (the subcutaneous inguinal ring) is 'placed opposite the
strongest part of the posterior wall (Fig. 77).

The Floor of the canal is formed by the upper surface of the
inguinal ligament and, at its medial end, by the lacunar ligament
(of Gimbernat).

The inferior (deep) epigastric artery arises from the external
iliac as it lies in the extra-peritoneal fat below the abdominal
inguinal (int. abd.) ring. At first the vessel lies below the ring,
but it bends upwards and medially along its medial border.
This relationship is of importance in connection with the
operation for strangulated inguinal hernia, and is referred to
again on p. 263.

Coverings of the Testis and Spermatic Cord. — In its
descent (p. 257) from the abdomen to the scrotum, the testis
traverses the inguinal canal. As it pushes its way through the
transversalis fascia at the abdominal inguinal ring, it gains for
itself and the spermatic cord a sheath of this fascia. This
covering is known as the internal spermatic or infundibuliform
fascia. The testis next passes under cover of the lower border
of the internal oblique, and as it does so, it drags down some
fibres of the muscle to form the cremaster. In the child, these
fibres can be traced from the inguinal ligament and the lower
border of the internal oblique down the anterior surface of the
cord and up its posterior surface to the pubic tubercle (spine).
Some extend to the testis, while others only pass downwards for
a short distance on the cord before looping upwards again.
This covering lies outside the internal spermatic fascia and is
known as the cremasteric muscle and fascia. The contraction of
the muscular fibres can draw the testis from the scrotum up to
the subcutaneous inguinal ring.

On passing through the external oblique aponeurosis at the
subcutaneous inguinal ring, the testis gains a third covering,
the external spermatic fascia.

From the above it will be seen that the testis and that part
of the spermatic cord which lies outside the inguinal canal have
three coverings. In the medial part of the canal the spermatic
cord has two coverings, and in the lateral part only one, the
internal spermatic fascia.

The Spermatic Cord can be examined in the upper part of

256

THE ABDOMEN AND PELVIS

FIG. 77. — Sections in the long axis of the Inguinal Canal.

1. The normal condition, showing the coverings of the spermatic cord.

2. Oblique inguinal hernia. Note the relation of the neck of the hernial sac to the
inferior epigastric artery and observe that the sac descends within the coverings of the
spermatic cord.

3. Direct inguinal hernia. Note the relation of the neck of the hernial sac to the
inferior epigastric artery and observe that the external spermatic (intercolumnar) fascia is
the only covering which it shares with the spermatic cord.

THE ABDOMINAL WALLS 257

the scrotum, and as it lies in front of the pubis after leaving
the subcutaneous inguinal ring. Surrounded by its coverings,
it lies immediately beneath the skin and the two layers of
superficial fascia (p. 240). The constituents of the cord — (i)
the ductus (vas) deferens, (2) numerous blood-vessels, (3)
lymphatics, and (4) nerves — are enclosed in the three coverings
which have already been described.

(1) The Ductus Deferens lies posteriorly in the cord and is
surrounded by the pampiniform plexus of veins. It possesses
a small lumen and a very thick muscular wall, and consequently
can easily be distinguished when the spermatic cord is examined.
Its artery of supply, from the superior vesical, is closely applied
to the duct.

(2) The Pampiniform Plexus of Veins ascends to the abdominal
inguinal (int. abd.) ring, and there forms the spermatic vein.
The External Spermatic (Cremasteric) Artery is derived from the
inferior epigastric -and is mainly distributed to the coverings.
The Internal Spermatic Artery, a branch of the abdominal aorta,
descends anteriorly in the cord and supplies the testis and
epididymis.

(3) The Lymphatics ascend from the testis and join the
lumbar or lateral aortic glands.

(4) The External Spermatic Nerve is a branch of the genito-
femoral (genito-crural). It supplies the cremaster muscle and
a sensory twig to the tunica vaginalis (Mackenzie). Numerous
sympathetic nerves run down on the coat of the internal
spermatic artery from the aortic plexus.

During attacks of renal colic, abnormal stimuli pass from
the ureter by the sympathetic to the lower thoracic and upper
lumbar segments. As a result, a viscero-sensory reflex is
established. Pain is felt in the loin (p. 354) and shoots down
to the testis (ext. spermatic nerve ; L. i and 2), but does not
affect the overlying skin of the scrotum (S. 2, 3, and 4). At the
same time a viscero-motor reflex may be set up, and the resulting
contraction of the cremaster muscle (ext. sperm, nerve) draws
the testis up towards the subcutaneous inguinal ring.

Descent of the Testis. — At an early period of development
the testis lies at the brim of the pelvis near the abdominal
inguinal ring. It is attached to the lateral wall of the abdomen
by a mesentery, the mesorchium, and is connected by the
gubernaculum to the integument which forms the lowest part
of the scrotum. This cord consists of condensed mesoderm,

17

258

THE ABDOMEN AND PELVIS

and later contains numerous unstriped muscle fibres. It is
present when the anterior abdominal wall is being formed, and
the muscles have to accommodate themselves so as to enclose
it in the inguinal canal. At the same time the umbilical arteries,
which lie medial to the testis, lift up a peritoneal fold so that
the gland projects into a small peritoneal fossa. Until the
seventh month this fossa lies opposite the abdominal inguinal

FiG. 78. — Diagrams to illustrate the Different Conditions of the
Processus Vaginalis.

a. Foetal condition, showing completely patent processus vaginalis.

b. Normal condition, with obliterated processus vaginalis and patent tunica vaginalis
testis.

c. d. The processus is only partially obliterated.
e. The closure of the processus has been oblique.

f. The funicular part of the process is shut off from the tunica vaginalis and repeated
attempts at obliteration have led to the valve-like constrictions.

f. Encysted hydrocele of the spermatic cord.
. As g, but the proximal part of the processus is patent.
/. As h, but a hydrocele is present in the tunica vaginalis.
k. Hydrocele of the tunica vaginalis.

/. One variety of encysted hernia, in which the closed abdominal end of the processus
vaginalis has been invaginated within the partially patent funicular part of the processus.
m. As I}, with, in addition, the sac of an acquired inguinal hernia.

ring, but during the eighth month it invades the inguinal canal.
At the same time it becomes elongated and forms the processus
vaginalis. Thereafter the testis enters the inguinal canal, and it
gains its permanent scrotal position during the ninth month. The
part of the processus which is related to the spermatic cord loses
its connection with the general peritoneal cavity and becomes
converted into a solid cord. The lower part of the processus
remains patent and constitutes the tunica vaginalis (p. 265).
Congenital Anomalies. — In Ectopia Testis the guber-

THE ABDOMINAL WALLS 259

naculum has failed to acquire its connection with the bottom
of the scrotum,, but instead has become attached to the skin
of the region in which the testis is found. It may lie in the
perineum, in the groin, or near the anterior superior iliac spine,
but it always maintains its normal relation to the processus
vaginalis, which is also misplaced.

Congenital Inguinal Hernia ; Congenital Hydrocele. —
Numerous developmental errors may occur in connection with
the closure of the processus vaginalis. All the congenital
varieties of inguinal hernia and of hydrocele result from such
errors. In Fig. 78 (b) the normal condition is depicted. The
processus remains patent below as the tunica vaginalis testis,
but above it is represented by a fibrous cord. In (a) the
processus remains patent throughout, i.e. a persistence of the
fcetal condition. If the opening at the neck is sufficiently wide,
bowel or omentum will enter the sac and pass down to its lower
end. It will then be in close contact with the testis and only
separated from it by the visceral layer of the patent tunica
vaginalis (vaginal type of oblique inguinal hernia). If the
opening at the neck is too small to permit .the passage of a
hernia, serous fluid from the peritoneal cavity may find its way
into the sac and give rise to an Intermittent Hydrocele. The
condition is not always present, as when the child lies down
the fluid passes back into the general peritoneal cavity. Owing
to this intermittent character, it may be mistaken for a hernia.
Further, it may be confused with a hydrocele of the cord or of
the tunica vaginalis, because it cannot be reduced by taxis.

In (c) the tunica vaginalis has been shut off, but the proximal
part of the processus remains patent and maintains its connection
with the general peritoneal cavity. This condition gives rise to
the Funicular Type of Oblique Inguinal Hernia, which constitutes
95 per cent (Stiles) of all congenital herniae. If the neck is not
large enough to admit a hernia, an intermittent hydrocele of
the funicular type may occur. The conditions shown in (d)
and (e) are very similar. The tunica vaginalis is closed above,
and the proximal part of the processus remains patent. In
both, but more especially in (e)} the line of closure has been
oblique and not horizontal as in (c). In order to open the sac
of a hernia of the funicular type affecting (e)} three layers of
peritoneum must be incised. This variety was formerly ex-
plained as an acquired hernia descending behind a partially
closed processus vaginalis.

17 a

260

THE ABDOMEN AND PELVIS

The processus may be shut off from the tunica vaginalis
below, and from the general peritoneal cavity above, but yet
remain patent in its intermediate part (g). Should this sac
become distended with serous fluid, it will form an Encysted
Hydrocele of the Cord. A similar variety is shown in (h). The
processus has been obliterated in two areas, but the patent
portions are so arranged that the occurrence of a funicular
hernia, an encysted hydrocele of the cord, and a hydrocele of the

tunica vaginalis
testis at one and
the same time is
quite possible (i).
In (I) an acquired
hernia is shown
invaginating an
encysted hydro-
cele, a condition which can only
occur when there is little fluid
in the hydrocele ; in (m) it is
seen passing down posteriorly.
In cases of imperfect descent of the
testis the processus vaginalis rarely
reaches the upper part of the scrotum
and never extends down into it. When
the testis is retained within the inguinal
canal at the subcutaneous inguinal ring,
FIG. 79.— Diagram of In- the processus js near]y always patent,

and should bowel or omentum descend
into it, the commonest type (inter-
parietal) of interstitial hernia is produced

abdominal'waTl have been C^g- 79)' The neck of the SOC lies at

removed. The patent the abdominal inguinal ring, and its
processus vaginalis and fundus lies between the external oblique

the peritoneum are shown . . . . . . n

in biue> aponeurosis and the internal oblique

muscle. The hernia may enlarge in the

region of the abdominal inguinal ring and give rise to a dilata-
tion of the sac, just beyond its neck. This enlargement lies be-
tween the fascia transversalis and the peritoneum, and is known
as a pro-peritoneal hernia. In this case it is associated with the
interstitial interparietal form. The whole hernia is dumb-bell
shaped, the constriction being placed at the abdominal inguinal
(int. abd.) ring.

guinal Canal to show the
Position of an Inter-
parietal Interstitial
Hernia. Portions of the
different layers of the

THE ABDOMINAL WALLS

261

If the testis with its patent processus emerges from the
inguinal canal but fails to descend into the scrotum,, a superficial
inguinal hernia may result. In these cases the sac is often
bilocular, the one enlargement being situated under the skin
and the other in the inguinal canal. Occasionally the sac of an
inguinal hernia not only extends into the scrotum but possesses
a second loculus either just outside or within the inguinal canal.

An Acquired Oblique Hernia enters the inguinal canal
at the abdominal inguinal ring and makes its way down into
the scrotum inside the spermatic cord (Fig. 77). The con-
stituents of the
cord are spread
out over the sur-
face of the sac and
the ductus defer-
ens is always found
on its posterior
aspect.

Inguinal Her-
nia: Radical Cure.
— The Incision for
inguinal hernia is
made along the
medial half or two-
thirds of the line
joining the anterior
superior iliac spine
to the root of the

penis, and should expose, in its lateral
part; the aponeurosis of the external
oblique. The fasciae of Camper and
Scarpa (p. 240) and the superficial epigastric and external pudic
arteries, which lie between them, are divided. At the medial
part of the wound the spermatic cord is exposed and the surgeon
can at once define the subcutaneous inguinal ring. The cord is
freed and lifted up to the surface, dragging the testis upwards
in the scrotum. In order to avoid injuring the ductus deferens,
forceps are carefully applied to the margins of the cord, which is
put on the stretch downwards and medially (Stiles). The external
spermatic fascia (p. 255) is very thin, and the muscular fibres of
the cremaster, which are very well marked in the male infant,
are visible through it. These two layers are carefully stripped off

M

i

h

CD

i

X

ij

w

u

2

D

i'

(/)

V)

i/)

K

Z

Z

(t

UJ

V-

0

•2

o

i/l

0

Q

•

Q
00

Z
I

u.

J

j

•A

v-

[Q
0

^«cx

°»

FIG. 80. — Diagram of the In-
guinal Canal to show the
Position of an Extra- parietal
Interstitial Hernia. Portions
of the different layers of the
abdominal wall have been
removed. The patent pro-
cessus vaginalis and the peri-
toneum are shown in blue.

262 THE ABDOMEN AND PELVIS

after they have been divided in the long axis of the cord. The
veins of the pampiniform plexus and the internal spermatic
artery can now be seen on the anterior surface of the sac, but
before they can be separated from it, the internal spermatic
(infundibuliform) fascia (p. 255) must be incised and stripped off.
If this is not done, difficulty will be experienced in separating
the vessels without injuring them. At the same time the
remaining veins and the ductus deferens should be freed from
the posterior aspect of the sac. The neck of the sac is carefully
isolated, ligated, and divided. It may be allowed to retract
into the abdomen or may be transplanted up the canal towards
the anterior superior iliac spine. The rest of the sac is removed,
but, if it is of the vaginal type (Fig. 78 (#)), the lower part may
be stitched up to form a closed tunica vaginalis testis.

The same approach and method of dividing the coverings
of the cord are employed in such conditions as varicocele (p. 264),
hydrocele of the cord, and hydrocele of the tunica vaginalis.

In infants or young people where the hernia is due to the
presence of a preformed sac and not to any inherent weakness
of the abdominal wall, the condition may be completely cured
by the removal of the sac, but it is sometimes advisable to insert
one or two stitches to narrow the subcutaneous inguinal ring or
to approximate the falx inguinalis (conjoined tendon) to the
inguinal ligament.

In elderly patients it is necessary to strengthen the weak
area in the abdominal wall which has predisposed them to
hernia. The external oblique aponeurosis is split up along
the course of the canal and the lower borders of the internal
oblique and the falx inguinalis are denned. A few mattress
sutures may now be passed through the deep surface of the
thickened lower portion of the external oblique aponeurosis,
which is forming the inguinal ligament, and up through the falx
inguinalis so as to drag the latter structure downwards behind
the former. The close relationship of the femoral vessels to the
inguinal ligament must be borne in mind when these sutures
are inserted. In this way the posterior wall of the inguinal
canal is greatly strengthened. A similar effect can be produced
in the anterior wall by uniting the two portions of the external
oblique in such a way that they overlap.

When sutures are being passed through the posterior wall
of the canal in the neighbourhood of the abdominal inguinal
(int. abd.) ring, the inferior epigastric vessels must be carefully

THE ABDOMINAL WALLS 263

avoided. In all cases where the canal is artificially narrowed,
the surgeon must guard against closing it too tightly lest undue
pressure be exerted on the spermatic cord.

Oblique inguinal hernia of long duration and great size tends
to take a more and more direct course through the abdominal
wall. The neck of the hernia gradually enlarges the abdominal
inguinal ring downwards and medially, until it comes to lie
directly behind the subcutaneous inguinal ring. In these cases,
after the hernia has been reduced, the examining ringer can be
passed directly backwards through the abdominal wall into the
abdomen. This alteration in the direction of the inguinal canal
is necessarily accompanied by an alteration in the direction
taken by the inferior epigastric artery. It now passes medially
to the pubic tubercle (spine) and then ascends behind the lateral
border of the rectus abdominis.

Direct Inguinal Hernia. — In the lower part of the anterior
abdominal wall the Triangle of Hesselbach can be identified.
Its base is formed by the medial end of the inguinal ligament,
its medial side by the lateral border of the rectus abdominis,
and its lateral side by the inferior epigastric artery, which
separates the triangle from the abdominal inguinal ring.
Occasionally, hernia occurs through the fascia transversalis in
the floor of Hesselbach's triangle. This variety, known as
a Direct (or Internal} Hernia, enters the inguinal canal at its
medial end arid immediately opposite the subcutaneous inguinal
(ext. abd.) ring. In doing so, it usually passes directly through
the falx inguinalis (conjoined tendon), though it may appear at
its lateral margin. Its subsequent course is the same as that of
an oblique hernia. The most important difference between
these two varieties (the direct and the oblique) lies in their
relationship to the inferior epigastric artery. The neck of the
sac of an oblique hernia is placed lateral to the artery, while
the neck of the sac of a direct hernia is medial to the vessel

(Fig. 77)-

In a case of old-standing inguinal hernia some difficulty
may be experienced in deciding which of the two varieties is
present, as in both cases the hernial opening is large and the
exploring ringer will pass directly through the abdominal wall.
Should such a hernia become strangulated, the surgeon will be
well advised to incise the constricting neck of the sac in an
upward and medial direction, in order to avoid the inferior
epigastric vessels. For if he mistakes a direct for an oblique

264 THE ABDOMEN AND PELVIS

hernia and incises the neck of the sac in a lateral direction, the
vessels will be wounded ; or if he mistakes an old-standing
oblique for a direct hernia and cuts in a medial direction, the
same accident will occur.

The incision for direct hernia is practically the same as that
employed in dealing with the oblique variety (p. 261), but the
coverings of the sac are somewhat different. After the external
spermatic fascia has been divided, the spermatic cord within
its cremasteric and infundibuliform fasciae is found lying to
the lateral side, and the hernia, covered by a thin expansion
from the falx inguinalis (conjoined tendon), to the medial side.
When this layer is incised the hernial sac is exposed covered by
a sheath which, though derived from the fascia transversalis,
is quite distinct from the internal spermatic (infundibuliform)
fascia of the cord (Fig. 77).

In the female, the inguinal canal is occupied by the round
ligament of the uterus, which is attached to the skin and fascia
of the labium majus. In the foetus, it also lodges a peritoneal
process, the Canal of Nuck, which corresponds to the processus
vaginalis in the male. At birth, the canal of Nuck should be
completely closed, but it may remain patent and give rise to
inguinal hernia. This condition occurs rarely in adult women,
but is not uncommon in female infants and young girls. As
the hernia increases in size it drags into its wall a part of the
suspensory ligament of the ovary (p. 387), which, at its lateral
extremity, is not far distant from the abdominal inguinal ring.
As a result the ovary and the distal part of the uterine (Fallopian)
tube are often found in the sac.

Imperfect closure of the canal of Nuck may lead to encysted
hydrocele of the round ligament.

Varicocele is a varicose condition of the veins of the
pampiniform plexus (p. 257). In adolescents it is almost
invariably on the left side, and many explanations have been
suggested, (a) The left spermatic vein, which is formed by the
union of the pampiniform veins, joins the left renal almost at
right angles, whereas the right spermatic vein joins the inferior
vena cava very obliquely. It has been urged that, owing to its
method of termination, the outflow from the spermatic vein is
not so free on the left side as it is on the right, (b) The total
length of the spermatic vein and pampiniform plexus is less
on the right side than the left, since the left testis hangs lower
in the scrotum and the left spermatic vein terminates at a higher

THE ABDOMINAL WALLS 265

level, (c) The valve at the orifice of the left spermatic vein
may be absent, (d) The venous return from the left spermatic
vein may be obstructed by the pressure of the iliac colon, behind
which it passes as it ascends on the iliacus (Fig. 88).

A varicocele on the right side generally indicates that the
right spermatic vein is pressed on by some tumour growth.

In this condition the veins of the plexus are much enlarged
and very tortuous, and, when they have been exposed (p. 262),
they must be separated from the ductus (vas) deferens. The
vessels are then ligated above and below and the intervening
portion is removed. The ligated ends are then tied together
and the coverings of the cord are united over them. In the
process the internal spermatic artery is not uncommonly
resected, but the testis receives a sufficient supply from the
artery to the ductus deferens, which becomes increased in size.

Undescended Testis (see also p. 258). — In embedding an
imperfectly descended testis in the scrotum, the preliminary
steps are much the same as in the operation for varicocele, but
the external oblique aponeurosis may have to be slit up from
the subcutaneous inguinal ring. It is generally found that the
ductus deferens is sufficiently long to allow the testis to be
placed at the bottom of the scrotum, but it will be necessary to
divide all the other constituents of the cord, together with its
coverings. As the testis increases in size about puberty,
operative interference should be undertaken a year or two
before that period in order that the circulation, temporarily
disturbed by the division of the internal spermatic artery, may
be completely and efficiently re-established for the nutrition of
the growing organ.

The Testis lies obliquely in the scrotum so that the upper
pole is antero-lateral to the lower, and the Epididymis is
closely applied to the lateral aspect of its posterior border.
Inside its fascial coverings (p. 255) the testis is invested by a
closed peritoneal sac, the Tunica Vaginalis. This sac possesses
a parietal layer, associated with the coverings (Fig. 81), and a
visceral layer, which covers the testis anteriorly, medially, and
laterally, but not posteriorly. The epididymis obtains a partial
covering from the visceral layer, and the medial aspect of its
body is separated from the postero-lateral aspect of the testis
by a small peritoneal recess — the sinus epididymidis (digital
fossa). In large hydroceles this fossa may become so deep as
to separate the two structures completely. Above the testis

266

THE ABDOMEN AND PELVIS

the tunica vaginalis extends upwards for a short distance on the
spermatic cord.

The testis possesses a capsule of connective tissue which is known as the
Tunica Albuginea (Fig. 81). Anteriorly and on each side it blends with the
visceral layer of the tunica vaginalis ; posteriorly, where it is in relation to
the epididymis and ductus (vas) deferens, it is greatly thickened to form the
Mediastinum Testis, which sends numerous septa into the body of the testis
to join the tunica albuginea. In this way the organ is subdivided into
lobules and these contain the Seminiferous Tubules. The blood-vessels break
up into capillaries on the deep surface of the tunica albuginea and on the sides
of the septa.

Hernial sac formed by
funicular process

Serous coat of gut

External spermatic
fascia

\ Cremasteric fascia

Internal spermatic
fascia

Tunica vaginalis
testis

Sinus of epididymis
Body of epididymis

FIG. 8 1. — Diagram of a Transverse Section through the Scrotum and Testes.

A shows the peritoneal relationships of the vaginal type of developmental inguinal hernia.

B shows the peritoneal relationships of the funicular type of developmental inguinal
hernia.

A corresponds to Fig. 78(0), and B corresponds to an exaggerated condition of
Fig. 78 (if).

In Excision of the Testis two routes are available. The
testis may be approached from below by incising the scrotum,
or the spermatic cord may be exposed above, as in the operation
for varicocele, and, by traction on it, the testis may be dragged
up out of the scrotum into the wound. The latter method is
preferable in malignant disease, as it enables the surgeon to
remove the testis, the spermatic cord, and the associated
lymphatics through the same incision. This route is also used
in tuberculous disease of the testis when there are no sinuses or
adhesions to the scrotum. If the latter conditions are present, the
lower route is adopted and the incision is planned so as to excise
the involved skin area. This method provides excellent drainage.

THE ABDOMINAL WALLS 267

The Epididymis begins in an enlargement which is situated
on the upper pole of the testis. This is termed the Head (globus
major), and it receives the efferent ducts of the testis, which
unite to form the convoluted Ducts of the Epididymis. The
body, which contains the downward continuation of the duct,
is much narrower than the head, and is closely applied to the
lateral aspect of the posterior border of the testis (Fig. 81).
Interiorly, the epididymis again enlarges to form the Tail
(globus minor}, and from its medial side the duct emerges as
the ductus (vas) defer ens, with greatly thickened walls. This
structure ascends along the medial side of the epididymis and
is closely related to the terminal branches of the internal
spermatic artery. At the upper pole of the testis the ductus
deferens enters the spermatic cord.

Development of the Testis and Epididymis. — Prior to the develop-
ment of the permanent kidneys, the embryo possesses two primitive kidneys,
the Wolffian bodies, which communicate with the cloaca by the Wolffian
ducts. The testis develops in close relation to the Wolffian body, and, as the
Wolffian body atrophies, the efferent ducts of the testis become connected
to the Wolffian duct, which forms both the epididymis and the ductus deferens
(p. 394). Most of the tubules of the Wolffian body disappear and the few
which persist constitute the Paradidymis or Organ of Giraldes, which is
situated in the lower part of the spermatic cord, just above the head of the
epididymis. The Mullerian ducts, which play such an important part in the
formation of the female generative organs (p. 394), disappear almost entirely
in the male. Each is represented by two Appendices Testis (the Hydatids of
Morgagni), which lie at the upper pole of the testis just in front of the epi-
didymis. Both the paradidymis and the appendices testis may give rise to
cysts, which frequently contain spermatozoa and are termed spermatoceles.
The prostatic utricle (sinus pocularis) represents the fused caudal ends of the
two Mullerian ducts.

In Hydrocele of the tunica vaginalis, fluid collects in the
sac and gradually distends it above, in front, and on each side
of the testis, giving rise to a somewhat egg-shaped swelling.
The testis and epididymis lie posterior to it, but in rare cases
inversion of the testis may be present. In this condition the
epididymis is related to the anterior border and the tunica
vaginalis to the posterior border and lateral surfaces of the
testis, while the ductus deferens occupies an anterior position
in the cord (Treves). Before tapping a hydrocele it is important
to determine the position of the testis with reference to the
swelling. The trochar and cannula are pushed through the
skin of the scrotum anteriorly in an upward and backward
direction. The distended tunica vaginalis is pierced from in
front (to avoid the testis) and near its lower pole (to facilitate
the evacuation of its contents). Care must be taken not to

268 THE ABDOMEN AND PELVIS

injure any of the superficial veins, as their dependent position
and the relief of tension following the operation may tend to
increase the amount of haemorrhage.

In the radical cure of a hydrocele the approach is very similar
to that employed in varicocele (p. 262). The hydrocele is
pushed upwards into the wound, and the coverings are incised
and dissected off. The parietal layer of the tunica vaginalis is
cut away along the lines of its reflection on to the testis and
epididymis, or a vertical incision may be made in the tunica
vaginalis anteriorly, and the two halves may then be folded back-
wards so that their edges can be united behind the epididymis.

Examination of the Testis and Spermatic Cord. — The
shape and consistence of the testis can readily be appreciated
when it is examined in situ, and any alteration of the normal
elastic feel, or variation in size or shape, should be carefully
observed. The epididymis can be felt along the postero-lateral
border. Although it is usually fixed in position, the epididymis
can sometimes be moved independently of the testis and yet
may be otherwise normal.

Enlargement of the tail (globus minor) of the epididymis is
not uncommonly associated with a bacterial infection ascending
along the ductus deferens from the urethra, such as occurs in
gonorrhoea. Tuberculous disease, on the other hand, usually
commences in the head (globus major), as the infection is carried
by the blood stream, and the bacilli settle down in the area
supplied by the epididymal branches of the internal spermatic
artery.

When acutely inflamed, the epididymis becomes sausage-
shaped. It is greatly swollen and tends to surround the posterior
part of the testis, which, though also enlarged, is rather obscured.
On the other hand, in acute inflammatory conditions of the
testis, the swelling resembles a Jaffa orange in shape, and the
epididymis cannot be easily defined. Both these conditions
may be somewhat masked by an associated acute hydrocele.

The ductus deferens can be felt along the postero-medial
border of the testis and may easily be distinguished in the
spermatic cord owing to its thick muscular wall. In tuberculous
disease, the duct is often irregularly thickened and its recognition
is still easier ; in varicocele, on the other hand, the increased
number and size of the veins may render its identification more
difficult. The presence of a hernial sac may be made out by
grasping the spermatic cord and allowing the individual structures

THE ABDOMINAL WALLS 269

to slip away from between the finger and thumb. If both cords
are examined at the same time,, the presence of an additional
structure on the affected side can often be determined.

In children, the cremasteric muscle may be so strongly
developed that it is able to draw the testis up into the inguinal
canal. The sudden disappearance from the scrotum of a lump
which may as suddenly reappear may lead the mother to suppose
that the child is suffering from a rupture, whereas the swelling
is simply the testis. Similarly, the condition of undescended
testicle may be mistaken for a rupture, if the mother fails to
notice the absence of the testis from the scrotum on the affected
side. Examination of the mobility of the testis can be carried
out by testing the cremasteric reflex. Gentle stroking of the
skin over the proximal part of the front of the thigh stimulates
the sensory branches of the genito-femoral (genito-crural) nerve
and causes a reflex contraction of the cremaster, which is supplied
by the motor part of the same nerve.

Posterior Abdominal Wall. — The Lumbo - dorsal
(Lumbar) Fascia is a strong aponeurotic layer which extends
between the ribs and the iliac crest. Laterally it gives origin
to the internal oblique and the transversus. Medially it splits
into three lamellae. Of these, the posterior reaches the lumbar
spines, and the middle the tips of the transverse processes.
They enclose between them the large sacro-spinalis (erector
spinse) muscle. The anterior lamella is attached to the bases
of the transverse processes ; between it and the middle lamella
the quadratus lumborum is situated (Fig. 82).

The posterior lamella of the lumbo-dorsal fascia is covered
by the latissimus dorsi, to which it partly gives origin. The
lateral margin of this muscle crosses the free posterior border
of the external oblique, and, together with a portion of the
iliac crest, they enclose the lumbar triangle of Petit. The roof
of this triangle is formed by the deep fascia of the back, and its
floor by the internal oblique (Fig. 74).

The upper lumbar triangle lies under cover of the latissimus
dorsi, above and to the medial side of the lumbar triangle of
Petit. It is bounded above by the twelfth rib ; medially, by
the lateral margin of the sacro-spinalis ; below, by the line of
origin of the internal oblique from the lumbo-dorsal fascia,
which corresponds to the lower border of the latissimus dorsi.
The floor of this space is formed by the lumbo-dorsal fascia,
and constitutes the weakest part of the posterior abdominal wall.

270

THE ABDOMEN AND PELVIS

Abscesses arising in connection with the vertebral column lie
between the fascial envelope of the abdomen (p. 271) and the
lumbo-dorsal fascia (Fig. 83). If the pus bursts through the
latter layer, it enters the upper lumbar triangle and then passes
downwards and laterally. Escaping from under cover of the
latissimus dorsi, it gains the lumbar triangle (of Petit) and points
above the iliac crest.

Linea alba

Rectus sheath, ant. wall

Rectus sheath, post, wall
Transversalis fascia

Peritoneum

Duodenum, third part
Ascending colon

I'eri-nephric
fascia

Lumbo-dorsal
fascia

Peri-nephric abscess

Lumbo-dorsal f., ant. layer
Lumbo-dorsal f., middle layer
Lumbo-dorsal f., post, layer
Gerota's space

FIG. 82. — Diagram of a Transverse Section through the Abdomen,

at the level of the Third Lumbar Vertebra.

On the left side, the normal arrangement of the fasciae is shown. On the
right side, the course taken by a peri-nephric abscess is represented. The pus
has perforated the peri-nephric and the lumbo-dorsal fasciae, and, after passing
downwards and laterally, has appeared at the lateral border of the latissimus
dorsi in the lumbar triangle (of Petit).

Abscesses which arise within the fascial envelope of the
abdomen tend to pass forwards round the abdominal wall in the
extra-peritoneal fat.

The Quadratus Lumborum is a flat muscle arising below from the iliac
crest and the ilio-lumbar ligament, which extends between the crest and the
transverse process of the fifth lumbar vertebra. It becomes narrower as it
passes upwards to be inserted into the twelfth rib. Anteriorly, it is clothed
by the anterior lamella of the lumbo-dorsal fascia, which separates it from
the medial continuation of the fascia transversalis (p. 271). Both muscles
acting together produce extension of the vertebral column ; one, acting alone,
produces lateral flexion. The nerve-supply is derived from L. i, 2, 3, and 4.

The Psoas Major occupies the groove between the bodies and transverse
processes of the lumbar vertebrae. It arises from the twelfth thoracic and all
the lumbar vertebras, and passes downwards and laterally along the margin

THE ABDOMINAL WALLS 271

of the brim of the pelvis. Passing behind the inguinal ligament, it enters
the thigh and is inserted into the lesser trochanter (p. 406). This muscle
forms a fleshy pad, which separates the kidney from the vertebral column.
It receives its nerve-supply from the anterior rami of L. 2 and 3.

The lliacus fills up the hollow on the ventral surface of the
ilium and has the psoas major related to its medial border.
Most of its fibres are inserted into the psoas tendon. It is
supplied by the femoral (ant. crural) nerve.

Both these muscles act together, and when the lower limb is
free to move they act as flexors of the hip-joint ; when the
lower limb is fixed, they act as flexors of the trunk.

The Fascia Iliaca, which is continuous above with the fascia
trans versalis and below with the parietal layer of the pelvic
fascia (p. 356), covers both the iliacus and the psoas. It is firmly
attached to the iliac crest and to the lateral part of the inguinal
ligament. Opposite the femoral vessels, it passes down into the
thigh, forming the posterior wall of the femoral sheath (p. 402).

Along the line of origin of the transversus from the lumbo-
dorsal fascia, the transversalis fascia becomes adherent to or
partially blended with the latter. As it is continued medially,
it is separated from the quadratus lumborum by the anterior
lamella of the lumbo-dorsal fascia, but it is in direct contact
with the psoas major (Fig. 82). At the lateral border of the
kidney the transversalis fascia splits to enclose both the kidney
and the suprarenal gland, but a fibrous partition separates the
two structures so that, when the fascia is incised, the kidney
can be drawn out while the suprarenal gland remains in place.

The fascia which surrounds the kidney is termed the
peri-nephric fascia. It limits a space (Gerota's), which is closed
above, below, and to the lateral side, but which is open medially,
where both layers are continued across the middle line. They
are separated from one another by the renal vessels, the aorta,
and inferior vena cava. The two layers meet inferiorly just
below the lower pole of the kidney, but they may, abnormally,
remain separate for a much greater distance. The latter condi-
tion constitutes a predisposing cause of movable kidney (p. 353).

The abdomen possesses a complete fascial envelope, which is
formed by (i) the fascia transversalis, (2) the diaphragmatic
fascia, (3) the peri-nephric fascia, (4) the fascia iliaca, and (5)
the pelvic fascia. Prolongations of this fascial envelope form
the femoral sheath and the internal spermatic or infundibuliform
fascia, which covers the testis and the spermatic cord.

The large blood-vessels of the abdomen' and pelvis lie inside

272

THE ABDOMEN AND PELVIS

the fascial envelope while the great nerves lie external to it

(P- 355)-

Psoas Abscess. — A cold abscess resulting from tuberculous
periostitis or osteo-myelitis of the lower thoracic or upper
lumbar vertebrae is limited in front by the anterior longitudinal
ligament and spreads in a lateral direction. In the lumbar
region it passes either into the substance of the psoas major
or between the muscle and its covering fascia ; in the thoracic

Left infra-colic compartment
Supra-colic compartment

Left para-colic gutter

Vermiform process,
perforated

Descending colon

Psoas abscess

FlG. 83. — Diagram of a Transverse Section through the Abdomen,

below the Lower Poles of the Kidneys.

On the left side, a psoas abscess is depicted, spreading laterally behind the
fascial envelope of the abdomen. The pus is separated from the quadrat us
lumborum by the anterior layer of the lumbo- dorsal fascia, and from the
descending colon by the transversalis fascia.

On the right side, an abscess is depicted in connection with a retro-caecal,
extra-peritoneal vermiform process. In this case the pus is situated inside
the fascial envelope of the abdomen.

region it enters the posterior mediastinum and, gravitating
downwards, passes into the abdomen behind the medial lumbo-
costal arch (int. arcuate ligament), which is simply the thickened
upper border of the psoas fascia. In both instances, therefore,
the abscess lies behind the psoas fascia, and its presence may
excite reflex contraction of the muscle with flexion at the
hip-joint. A similar reflex is often observed in appendicular
inflammation, and in other cases where the muscle is irritated.
Direction of Spread. — (i) The pus may pass laterally behind

THE ABDOMINAL WALLS 273

the peri-nephric fascia and in front of the quadratus lumborum
(Fig. 83), and so reach the anterior surface of the lumbo-dorsal
fascia near the origin of the trans versus abdominis (trans versalis).
At this point the peri-nephric and trans versalis fasciae become
continuous, but they are both adherent to the origin of the
muscle and check further spread in a lateral direction. The
pus may perforate the lumbo-dorsal fascia and enter the upper
lumbar triangle, from which it may spread to the lumbar
triangle (of Petit) (p. 269).

(2) The pus may follow the direction of the psoas major and
enter the thigh behind the inguinal ligament. In its course it
may infect and erode the sacro-iliac joint, or it may spread to the
bursa which separates the tendon of the muscle from the hip-joint.
When this bursa communicates with the joint, the latter also may
become infected. This condition is referred to again on p. 423.

(3) The pus may pass downwards at first and then, spreading
laterally, gain the iliac fossa where it lies behind the fascia iliaca.
Its presence in this situation may be recognised on abdominal
palpation. At the iliac crest both the fascia iliaca and fascia
transversalis are bound down to the bone, but, should the abscess
increase in size, their attachments are not strong enough to limit
it to the iliac fossa, and it may come towards .the surface near
the anterior superior iliac spine. In these cases it is advisable
to evacuate the pus, and the muscles may be divided by a grid-
iron incision. The transversalis fascia is not incised, but is
separated from the trans versus muscle until the abscess is reached.

(4) The pus may occasionally pass backwards, following the
course of the dorsal branch of a lumbar artery. It usually
passes medial to the sacro-spinalis and points near the posterior
median line, or it may spread upwards and downwards within
the sheath of the muscle (Fig. 83).

The Approach to the Kidney from behind.— In
nephropexy and other operations which do not necessitate the
exposure of the ureter, a vertical incision along the lateral border
of the sacro-spinalis (erector spince) gives good access. After
the skin and fasciae have been divided, the oblique lower fibres
of the latissimus dorsi are cut across in the line of the incision,
exposing the lumbo-dorsal fascia (lumbar aponeurosis), which
is also incised vertically. In the upper part of the wound, the
posterior layer of the peri-nephric fascia is now exposed, but,
below, the lateral margin of the quadratus lumborum, which
crosses the wound obliquely (p. 270), must be divided together

18

274

THE ABDOMEN AND PELVIS

with the anterior layer of the lumbo-dorsal fascia on its anterior
surface. When the edges of the wound are widely retracted,
the last thoracic, ilio-hypogastric and ilio-inguinal nerves may
be seen running downwards and laterally behind the peri-nephric

Trapezius

Latissimus dorsi

Spleen - -

Left kidney 4- —

Left ureter

I Lumbo-dorsal fascia,
middle layer
Quadratus lumborum

External oblique
4 Sacro-spinalis

Lumbp-dorsal fascia,
posterior layer

Glutseus maximus

FIG. 84. — The Position and Posterior Relations of the Kidney.

On the right side, the lower part of the latissimus dorsi has been removed
and a rectangular flap of the posterior layer of the lumbo-dorsal fascia has
been turned laterally. A part of the sacro-spinalis has been resected, exposing
the tips of the transverse processes of the 2nd and 3rd lumbar vertebrae and
the middle layer of the lumbo-dorsal fascia. A rectangular flap of the fascia
has been turned laterally in order to expose the quadratus lumborum.

On the left side, the relations of the spleen and left kidney to the lung and
pleural sac are indicated on the surface.

fascia. When the latter is opened, the peri-renal fat can readily
be separated from the kidney with the finger.

When freer access is desired, e.g. in exploratory operations
necessitating the exposure of the ureter, the oblique lumbo-ilio-
inguinal incision may be preferred. It commences above in
the angle between the twelfth rib and the. sacro-spinalis, and is
carried downwards and laterally in the direction of the anterior
superior iliac spine. If necessary, it may be continued medially

THE ABDOMINAL WALLS 275

above the lateral part of the inguinal ligament, being limited
by the abdominal inguinal (int. abd.) ring.

The lower fibres of the latissimus dorsi are cut across, exposing
the lumbo-dorsal fascia above and the internal oblique below.
These structures are divided in the line of the skin incision, and
the lateral part of the wound is deepened through the transversus
abdominis until the fascia trans versalis is reached. The pos-
terior layer of the peri-nephric fascia, which is the continuation
of the fascia transversalis in a medial direction, has already been
exposed by the division of the lumbo-dorsal fascia. It is now
incised, and the kidney and the commencement of the ureter
are found in the peri-renal fat. As the ureter is traced down-
wards, it becomes necessary to divide the fascia transversalis,
which has so far been preserved intact. This is done with great
care because, owing to the scantiness of the extra-peritoneal
fat in this region, there is danger of opening the peritoneal
cavity. In addition, the descending colon is retro-peritoneal
and the posterior wall of the gut or its blood-vessels may be
injured unless great care is exercised.

When the whole incision is employed, the ureter can be
traced from its commencement in Gerota's space through the
anterior layer of the peri-nephric fascia into the extra-peritoneal
fat, and then downwards to the pelvis.

In the process, the peritoneum is stripped off the posterior
abdominal wall and serves to keep the abdominal contents
away from the field of the operation.

The danger of opening the pleural sac at the upper end of
the wound must also be borne in mind. The lower limit of the
sac posteriorly (p. 509) lies in front of the last rib, at the point
where the rib is crossed by the lateral margin of the sacro-spinalis.
Frequently the last rib is so short that its extremity cannot be
felt. In these cases the eleventh rib may be mistaken for the
twelfth, and if so, the pleura will be opened at the upper part
of the wound as the incision is deepened. This danger can be
avoided by counting the ribs from above downwards and so
determining whether the lowest palpable rib is the eleventh or
the twelfth. Further, on rare occasions, the pleura may lie at
a lower level than normal, and cross the apex of the angle between
the twelfth rib and the sacro-spinalis. It is then very difficult
to avoid opening the pleural sac.

It may be necessary, e.g. after radiographic localisation of
ureteral calculi, to expose the ureter without exploring the kidney,

276 THE ABDOMEN AND PELVIS

and, in this case, the oblique incision need not extend so high
as the angle between the sacro-spinalis and the last rib. The
fascia transversalis may be incised as soon as it is reached, and
the surgeon then works medially, stripping the peritoneum off
the posterior abdominal wall, until the anterior surface of the
psoas major is recognised. On the other hand, the fascia
transversalis may be left intact and the surgeon works medially,
stripping it and the fascia iliaca forwards as a continuous sheet.
When the psoas major is reached, the fascia is carefully torn
through with the finger nail. Whatever method is employed
the ureter will be found adherent to the posterior aspect of the
peritoneum, and its presence there can readily be detected if the
pulp of the finger is turned forwards and lightly drawn across
its course. When it has been separated from the peritoneum,
the ureter can be brought up to the surface and incised to permit
of exploration with probes or the removal of a calculus. Owing
to its rich blood-supply (p. 354), incisions in the ureter soon heal,
and, for the same reason, complete isolation of the duct is not
followed by damage from sloughing.

THE ABDOMINAL CAVITY.

The differences which exist between the living subject and
the dissecting-room cadaver are probably more marked in the
abdomen than in any other part of the body. The action of
the preservatives used not only renders firm those organs which
are pliant in life, such as the liver and the spleen, but also
produces shrinkage of the abdominal contents and retraction
of the anterior wall. In addition the living peritoneum possesses
a certain amount of mobility on the extra-peritoneal fat, and
can stretch or be stretched without tearing, but both these
characteristic features disappear after death. As a result, the
positions of viscera relative to the vertebral column, as found
in the cadaver preserved and dissected in the horizontal position,
differ somewhat from those which they occupy in the living
subject, more especially when the body is in the erect posture.

With the exception of the retroperitoneal viscera, which are
practically fixed, the positions of viscera relative to the surface
vary within wide limits. The influences which govern these varia-
tions are (i) posture, (2) the personal factor, (3) the physiological,
and (4) the pathological condition at the time of examination.

THE ABDOMINAL CAVITY 277

The Peritoneum is a highly absorptive serous membrane,
which lines the abdominal and pelvic cavities (parietal layer),
and is more or less intimately related to the viscera contained
by them (visceral layer). In the male it' forms a completely
closed sac, but in the female it communicates with the cavities
of the uterus and vagina through the ostium abdominale of the
uterine (Fallopian) tube. Infective conditions, therefore, may
ascend to the peritoneal sac through the vagina, uterus, and
tubes, as, for example, in acute gonorrhceal peritonitis.

The deep surface of the anterior abdominal wall is completely
lined by peritoneum. Below the umbilicus it forms an
uninterrupted sheet so that when the cavity has been opened,
the hand may be introduced and passed across to the opposite
s:de without meeting any normal obstruction. Above the
umbilicus, a fold of peritoneum, consisting of two layers — the
falciform ligament — passes backwards to the liver and forms
an imperfect partition. Its lower border, where the two
constituent layers become continuous, is free and contains the
ligamentum teres and the associated para-umbilical veins (p. 243).
Although its anterior attachment is in the middle line, the
falciform ligament passes backwards and slightly to the right.
On this account, when supra-umbilical median incisions are
enlarged in a downward direction, they should be carried round
the left s'de of the umbilicus, so as to obviate the necessity for
cutting through the ligamentum teres and the associated veins.

The peritoneum lining the anterior abdominal wall sweeps
upwards on to the inferior surface of the diaphragm, and is
then reflected on to the liver (Fig. 85) and stomach. Between
the hepatic and gastric reflections, the peritoneum on the under
surface of the diaphragm becomes continuous with the anterior
layer of the lesser omentum.

In Fig. 85 the peritoneum is shown passing from the
diaphragm to the liver in two layers, which cover its anterior
and posterior surfaces and meet on the inferior surface at the
porta hepatis (transverse fissure). They then descend to the
lesser curvature of the stomach as a broad sheet which is termed
the lesser omentum. After enclosing the stomach and con-
stituting its serous coat they again meet one another, and
descend for a variable distance towards the pelvis. Inferiorly
they are folded sharply upwards and ascend to the transverse
colon. This large peritoneal sheet, which connects the transverse
colon to the stomach, is termed the greater omentum.

18 a

278

THE ABDOMEN AND PELVIS

Originally it consisted of two layers above and four layers below,
as shown in Fig. 85, but these layers may become completely
fused, and in the living subject it is not always possible to
distinguish more than one layer.

Lesser omentum

Stomach

Omental bursa
(O.T. small sac)

Great sac

Greater omentum

Uterus
Urinary Bladder

Liver

Epiploic foramen
(O.T. foramen
of Winslow)

Pancreas

Duodenum,
3rd part
Transverse colon

Mesentery of
small intestine

Small intestine

Rectum

FIG. 85. — Sagittal Section of Abdomen showing the arrangement
of the Peritoneum.

The two posterior layers of the greater omentum, having
enclosed the transverse colon, pass backwards and upwards to
the posterior abdominal wall, as the transverse meso-colon,
and there they separate along the anterior bordei of the pancreas
on a level with the second lumbar vertebra. The superior layer
passes upwards over the posterior abdominal wall and is then

THE ABDOMINAL CAVITY 279

reflected forwards on to the liver. The inferior layer passes
downwards and forms a complete covering to the posterior
abdominal wall below the pancreas. Along a line passing
obliquely downwards and to the right, it 'is lifted off the wall
to form the mesentery, which encloses the jejunum and ileum.
After covering the pelvic viscera (p. 357), this layer passes
upwards on the anterior abdominal wall.

It will be seen from Fig. 85 that a portion of the peritoneal
cavity is shut off behind the stomach. This is the Omental
Bursa (Lesser Sac). It is a developmental diverticulum
(p. 303) of the great sac, with which it communicates through
a single opening, the epiploic foramen (of Winslow).

The Greater Omentum forms a protective covering over
the abdominal viscera below the level of the stomach. It
contains a variable amount of fat, and is usually the first structure
seen when the abdomen is opened. The lower and the lateral
margins are free, and it can therefore be easily moved about
in abdominal operations. In addition, the greater omentum
wanders to any region of the abdomen where inflammatory pro-
cesses exist, and the surrounding adhesions which it forms are of
great value in limiting the spread of infection. On this account
it has been termed by Morison the "policeman of the abdomen."

The Lesser Omentum passes from the lesser curvature of
the stomach and the corresponding border of the first inch and
a half of the duodenum to the porta (transverse fissure) of the
liver. The two layers of which it consists are closely applied
to one another, and form a thin, transparent sheet, save near
the right border where they are separated by the portal vein,
bile-duct, and hepatic artery. Round this border, which is
free and unattached, the two layers become continuous (Fig. 86).
Occasionally the lesser omentum is continued beyond the vessels
and duct, and receives attachment to the inferior surface of the
gall-bladder. Its free border may then be traced downwards
over the duodenum to the transverse colon, and on this account
the additional part is called the hepato-colic ligament. It
contains no vessels of any size, but the gall-bladder lies within
its upper attachment. It may be cut through parallel to the
gall bladder in exploring the epiploic foramen.

The Epiploic Foramen (of Winslow) lies behind the right
free border of the lesser omentum. It is bounded above by the
liver (caudate lobe), and behind by the peritoneum which covers
the inferior vena cava. Below it is limited by the first part of

18 b

280

THE ABDOMEN AND PELVIS

the duodenum. In certain cases, e.g. examination of the bile-
duct, it is necessary to explore the epiploic foramen. This can
be effected by passing the finger backwards and to the left along
the postero-lateral surface of the gall bladder till it reaches
the neck. The finger then slips behind the right margin of the
lesser omentum and enters the foramen.

9 10 II 12

FIG. 86. — Transverse Section of Abdomen at the" level of the
Epiploic Foramen (of Winslow).

1. Omental bursa (O.T. small sac).

2. Omental tubercle of liver.

3. Great sac.

4. Stomach.

5. Gastro - splenic ligament

gastro-splenic omentum).

6. Spleen.

7. Lieno-renal ligament.

8. Left kidney.

9. Diaphragm.

(O.T.

10. Aorta.

11. Inferior vena cava.

12. Right kidney. [Winslow).

13. Epiploic foramen (O.T. foramen of

14. Liver.

15. Gallbladder.

16. Bile-duct.

17. Portal vein.

1 8. Hepatic artery.
19. Falciform ligament.

The Omental Bursa (Lesser Sac) extends upwards between
the liver and the diaphragm to the upper end of the caudate
(Spigelian) lobe (Fig. 85). Below it rarely extends beyond the
transverse colon, owing to the fusion of the anterior and posterior
layers of the greater omentum. Its anterior wall is formed,
from above downwards, by (i) the liver, (2) the lesser omentum,
(3) the postero-inferior surface of the stomach, and (4) the two
anterior layers of the greater omentum. Its posterior wall is
formed, from below upwards, by (i) the transverse colon, (2)

THE ABDOMINAL CAVJTY

281

the transverse meso-colon, (3) the anterior surface of the pancreas,
and (4) the upper pole of the left kidney, the left suprarenal
gland, and the diaphragm.

When a transverse section is made through the abdomen
so as to pass through the epiploic foramen, the connection of
the omental bursa with the great sac is at once demonstrated
(Fig. 86). On the left side, at this level, the two layers of

FIG. 87. — Transverse Section of Abdomen, immediately below the
Epiploic Foramen.

12. Inferior vena cava.

13. Right suprarenal gland.

14. Right kidney.

15. Great sac.

16. Bile-duct.

17. Gastro-duodenal artery.

1 8. Liver.

19. Duodenum, ist part.

ii. Portal vein. 20. Falciform ligament.

1. Omental bursa (O.T. small sac).

2. Stomach. 3. Great sac. 4. Great sac.

5. Gastro-splenic ligament (O.T. gastro-

splenic omentum).

6. Lieno-renal ligament.

7. Left kidney.

8. Pancreas.

9. Left suprarenal gland.
10. Aorta.

peritoneum which enclose the stomach pass backwards from the
fundus to form the gastro- splenic ligament. At the hilum of the
spleen, the lateral (originally anterior) layer gives a complete
investment to that organ, which therefore projects into the
supra-colic compartment of the peritoneal cavity. From the
hilum, the two layers pass backwards to the left kidney as the
lieno-renal ligament and then they diverge, the one lining the
great sac and the other the omental bursa. These two folds,
together with the hilum of the spleen, form the left boundary

282 THE ABDOMEN AND PELVIS

of the omental bursa and completely shut it off from the great
sac on this side. Below the level of the spleen, the gastro-
splenic ligament is directly continuous with the two anterior
layers of the greater omentum, i.e. there is no break in the
continuity of the wall of the bursa.

Transverse sections made through the omental bursa below
the epiploic foramen show it as a completely closed sac. In
Fig. 87 the section passes through the pylorus and the first
part of the duodenum. The peritoneum on the posterior aspect
of the stomach passes to the right and covers rather less than
the first inch of the duodenum before it passes backwards on to
the head of the pancreas.

This reflection forms the right border of the omental bursa,
and the hepatic artery passes forwards round it in order to
reach the lesser omentum.

Drainage of the Peritoneal Cavity.— Collections of fluid

in the peritoneal cavity differ in situation according to the position
of the patient, and, unless they are limited by adhesions, they
spread in a downward direction when the patient is in the erect
or semi-sitting posture. In the supine position, they will tend
to pass upwards towards the diaphragm. In the post-operative
treatment of inflammatory effusions, the patient is usually placed
in the Fowler (semi-sitting) position in order to diminish the
risk of upward spread into the sub-diaphragmatic region (p. 283).

The peritoneal cavity is naturally subdivided into the pelvis
and the abdomen proper, and the latter is further subdivided
by the large sheets of peritoneum which form the greater
omentum and the mesentery.

The uppermost or Supra - colic Compartment lies above
and in front of the greater omentum. It is partially subdivided
into a right and a left half by the falciform ligament of the liver,
and its contents include the liver, the gall-bladder, the stomach,
the first part of the duodenum, the spleen, and the upper poles
of both kidneys. The omental bursa (lesser sac) may be regarded
as a large diverticulum of the supra-colic compartment. In
addition other, smaller, recesses occur : (i) between the upper
surface of the liver and the under surface of the diaphragm
(Fig. 85) ; (2) the hepato-renal recess of Morrison, between
the under surface of the liver above and the right kidney and the
right (hepatic) flexure of the colon below ; and (3) between the
spleen and the left kidney.

Anteriorly, the supra-colic compartment is bounded by the

THE ABDOMINAL CAVITY 283

anterior abdominal wall ; posteriorly, it is limited by the lesser
omentum, stomach, and greater omentum, which together form
an oblique surface, sloping backwards and to the right. When
pus or septic fluid, e.g. from a leaking ulcer of the duodenum or
anterior wall of stomach, is present in this compartment, it may
remain localised owing to adhesions between the greater omentum
and the anterior abdominal wall. Its downward spread is thus
prevented, and owing to the slope of the posterior wall, the fluid
tends to pass into the hepato-renal recess. With the body in
the horizontal position it readily spreads from this situation
round the free border of the right triangular (lateral) ligament
of the liver into the recess between the liver and the diaphragm.
The infection of this intra-peritoneal subphrenic area is a very
serious condition, because the lymphatics of the peritoneum on
the under surface of the diaphragm communicate very freely
with those of the pleura, and empysema or abscess of the lung
may complicate the existing peritonitis, with fatal results.

The hepato-renal recess of Morison may be drained through
an incision made below the twelfth rib and at the lateral margin
of the kidney. This pierces, in turn, the skin, fasciae, latissimus
dorsi, the obliques, transversus, transversalis fascia, and
peritoneum. A tube thus passed into the recess affords good
drainage if the patient is placed in the Fowler (semi-sitting)
attitude. In this way the spread of infection into the subphrenic
danger zone may be successfully prevented.

After perforation of an ulcer on the posterior wall of the
stomach, the fluid may be prevented from escaping from the
omental bursa by adhesions closing the epiploic foramen (of
Winslow). The bursa then becomes distended and may best
be drained by means of a tube passed through the lesser omentum
from the median incision, which is employed in such cases (p. 294).
In addition a counter opening may be made in the left side,
below the twelfth rib and lateral to the descending colon, and a
tube passed upwards and medially in front of the left colic
flexure may be introduced into the bursa through the lower
part of the gastro-splenic ligament.

If the epiploic foramen is patent, the fluid passes out into
the supra-colic compartment and at once invades the hepato-
renal recess of Morison (Fig. 86). In this case, both the recess
and the bursa will require to be drained.

The Infra -colic Compartment lies behind the greater
omentum, transverse colon, and meso-colon, and is subdivided

284

THE ABDOMEN AND PELVIS

into two, a right and a left, by the mesentery, which extends
from the left side of the second lumbar vertebra downwards

FIG. 88. — The Posterior Wall of the Infra-colic Compartment. The greater
omentum and the transverse colon have been thrown upwards. The
mesentery has been divided close to its root and removed together with
the coils of the jejunum and ileum. A small part of the pelvic colon
and its mesentery has been resected to expose the pelvic portion of the
left ureter.

and to the right for about six inches and terminates at the
ileo-colic junction. Coils of small intestine occupy both sub-
divisions, and must be displaced when the compartment is being
explored. This displacement,, to be effectual, must be at right

THE ABDOMINAL CAVITY 285

angles to the line of mesenteric attachment, i.e. upwards and to
the right or downwards and to the left. Owing to the " lie " of
the mesentery; endeavours to draw the gut downwards and to the
right or upwards and to the left cannot meet with much success.

The right infra- colic compartment, bounded above by the
root of the transverse meso-colon, to the right by the ascending
colon, and to the left by the root of the mesentery, is roughly
triangular in shape (Fig. 88). It can be exposed by drawing
the greater omentum upwards and displacing the coils of small
intestine downwards and to the left. The peritoneum on its
posterior wall covers the lower pole of the right kidney, the
second and third parts of the duodenum, a small part of the
head and neck of the pancreas, and the right ureter and psoas
major muscle (Fig. 88).

Owing to the protection which it receives from the greater
omentum, this compartment is rarely infected by a downward
spread, and as its lower extremity is closed (Fig. 88), it is not com-
monly infected by an upward spread from the pelvis. Primary
infection is rare ; it is usually due to the vermiform process
(P- 331)- Drainage may be obtained through the appendicular
wound by means of a tube passed upwards and to the left,
medial to the ascending colon and behind the greater omentum.

The left infra-colic compartment is bounded to the right by
the root of the mesentery and to the left by the descending and
iliac cola ; below, it is bounded on the left side by the ascending
part of the pelvic meso-colon, but on the right side it opens
freely into the pelvis (Fig. 88). It can be exposed by drawing
the greater omentum upwards and displacing the small intestine
upwards and to the right. The peritoneum on its posterior wall
covers the lower pole of the left kidney, the inferior surface of
the body of the pancreas, and the duodeno-jejunal flexure
above ; the left ureter, the inferior mesenteric and superior
hsemorrhoidal vessels, and the left psoas major below.

Either infra-colic compartment may be the site of a
tuberculous abscess, following the breaking down of caseous
mesenteric lymph glands.

The right para-colic gutter lies along the lateral side of
the ascending colon, and its floor is formed by the peritoneal
reflection from the gut to the lateral wall of the abdomen. Above,
it opens into the hepato -renal recess of Morison ; below, it
passes round or behind the caecum and communicates with the
pelvis over the medial border of the psoas major. Infection of

286 THE ABDOMEN AND PELVIS

this gutter may occur by downward spread from Morison's
pouch and the omental bursa, and this condition may be suspected
in those cases of perforated gastric or duodenal ulcer in which
pain is felt over the right iliac fossa. Owing to the presence
of this channel, stomach contents may be found in the pelvis,,
even when the greater omentum is adherent to the anterior
abdominal wall. Pus from a retro-csecal (intra-peritoneal,
p. 333) abscess may spread upwards along the right para-colic
gutter into the loin and possibly to the subphrenic danger zone.

Drainage is conveniently carried out through a stab wound
just above the iliac crest by means of a tube, which can be
drawn out in front through the appendicular incision. The
wound must be on the lateral side of the ascending colon, and
great care must be taken to avoid injuring the gut.

The left para-colic gutter extends along the lateral side
of the descending and iliac cola and opens freely into the pelvis
at its lower end. Its upper extremity is separated from the
spleen and the lieno-renal recess by the phrenico-colic ligament,
a fold of peritoneum which passes laterally from the left colic
(splenic) flexure to the diaphragm. It may be infected from
the supra-colic compartment or by upward spread from the
pelvis. Drainage may be obtained through a small grid-iron
incision in the left iliac fossa, and a stab wound similar to that
employed on the right side. A tube may then be passed through
from back to front.

The basin of the Pelvis is formed by the utero-rectal pouch
in the female and by the recto-vesical pouch in the male.
Primary infection is due to pathological conditions of the
vermiform process (p. 331) or the pelvic viscera. Secondary
infection is extremely common, as both para-colic gutters, the
supra-colic compartment (in the absence of omental adhesions),
and both infra-colic compartments drain into the pelvis.

In the female, owing to the peritoneal relations of the vagina
(p. 387), the pelvis may be drained through an incision in the
upper part of the posterior fornix. It has been suggested that,
in the male, drainage may be obtained through an incision into
the rectum from the bottom of the recto-vesical pouch. The
usual method, however, is to drain by means of tubes passed
downwards and backwards from a median supra-pubic incision,
or downwards and medially from iliac grid-iron incisions.

In all cases of pelvic inflammation, the patient is placed in
the Fowler (semi-sitting) posture, and the assistance of gravity

THE ABDOMINAL CAVITY

287

is obtained to prevent the upward spread into the various
compartments of the abdomen proper.

Congenital Hernise. — In a three weeks' human embryo,
the alimentary canal may be subdivided into the fore-gut, the
mid-gut, and the hind-gut (Fig. 89). They form a tube, which
is closed at its cephalic and caudal ends, but which communicates
with the yolk-sac through the vitello-intestinal duct. At the
junction of the mid- and the hind-gut, the allantois forms a
short blind diverticulum which grows into the body-stalk. At
this period the mesoderm lining the ccelom, or body-cavity, of
the embryo is directly continuous with the mesoderm lining

Spinal part of neural tube

Notochord
Fore
Hind-brain

Mid-gut

| Amnion cavity

Ectoderm of amnion

Mesoderm of amnion

Hind-gut

Mid-brain „

Fore-brain
Stomatodaeum

Pericardium (heart not shown)

Rudiment of liver

Allantcic diverticulum
Mesoderm of yolk-sac

Umbilical orifice Entoderm
FIG. 89. — Schema of Sagittal Section of Embryo, after the formation
of the Head and Tail Folds.

the cavity — exo-ccelom — in which the yolk-sac lies, and con-
sequently the two spaces communicate with one another. The
anterior or cephalic part of the ccelom is destined to form the
pleural and pericardial sacs, while the rest becomes the peritoneal
cavity. As the amnion (Fig. 89), which at first lies dorsal to
the embryo, grows round its ends and sides, the exo-ccelom is
encroached on, and the body-stalk is brought closer to the
yolk-sac. In this way the umbilical cord is formed, and at first
it contains the yolk-sac, the rapidly narrowing vitello-intestinal
duct, and the remains of the exo-ccelom in addition to the
blood-vessels of the body-stalk, the whole being surrounded by
the amnion (Fig. 90).

As the abdominal part of the alimentary canal increases in
length, it drags the peritoneum away from the dorsal wall, and

288

THE ABDOMEN AND PELVIS

so acquires a dorsal mesentery. A loop of gut is thus formed,
and as the abdominal walls do not grow at the same rapid rate,
it descends through the large patent umbilicus and lies in the
exo-ccelom within the umbilical cord. At the end of the third
month the abdominal cavity is large enough to contain all its
viscera, and the intestinal loop returns into the abdomen. The
exo-ccelom then becomes completely obliterated, and no trace

CEsophagus

Rudiment of respiratory system
Notochord j

Medulla spinalis

Ectoderm of embryo

Liver diverticulum branching in septum transversum
j Stomach

Dorsal pancreas rudiment

Ventral pancreas rudiment
Peritoneal part of ccelum
Caecum

Peritoneal part of
celum

Wolffian duct

Rectum

Hypophysis-

Cloacal membrane

Rathke's pouch

Ectoderm of amnion

Mesoderm of amnion

Cerebral hemisphere

Umbilical cord
Placental mesoderm

Pericardium |
Gall-bladder rudiment

'I Yolk-sac

Septum transversum

FIG. 90. — Schema of a Sagittal Section through a Human Embryo,
after the rotation of the intestinal loop.

of it should be found in the umbilical cord at birth. Thus
during the second and third months the human embryo normally
possesses an umbilical hernia. If the loop of gut fails to return
within the abdomen, or if the exo-ccelom remains patent and
retains its connection with the peritoneal cavity, a congenital
umbilical hernia will result.

Congenital diaphragmatic hernia is due to imperfect develop-
ment of the septum transversum, which ought to separate
the pleural and peritoneal sacs completely from one another.

THE ABDOMINAL CAVITY 289

The site of the hernia lies postero-lateral to the oesophageal
opening in the diaphragm, as this is normally the last part of
the diaphragm to develop.

Congenital inguinal hernia is dealt with on p. 259.

The Stomach is almost completely invested by peritoneum,
and consequently possesses a wide range of movement. Its
proximal or cardiac end, however, is firmly fixed in position
owing to its continuity with the oesophagus. It lies behind the
seventh left costal cartilage one inch from the median plane,
and at a depth of four inches from the anterior surface of the
body. On the posterior surface the cardia can be mapped out
at a distance of one inch to the left of the ninth thoracic spine.

The fundus of the stomach is that part of the organ which
lies above and to the left of the cardia, when the body is in the
supine position. It bulges upwards into the left cupola of the
diaphragm, and its upper limit reaches the fifth rib behind the
pericardium and apex of the heart. Distention of the fundus
with gas may mechanically produce cardiac discomfort by
direct pressure. In the erect position, the upward projection
of the fundus is diminished, and it tends to become absorbed
into the greater curvature.

The long axis of the stomach is directed downwards, forwards,
and to the right. Its antero-superior surface is directed upwards
and forwards and lies in relation to the left half of the diaphragm
and the inferior aspect of the liver. A large part of this surface,
which lies medial to the left costal margin and below the inferior
border of the liver, is in direct contact with the anterior abdominal
wall. The whole surface helps to form the posterior wall of the
supra-colic compartment, which is therefore infected by the
perforation of a gastric ulcer situated in this part of the stomach.

The postero-inferior surface of the stomach looks downwards
and backwards, and is in relation with a number of structures,
which constitute the stomach-bed. In its upper part, this
surface is in contact with the left half of the diaphragm, the left
kidney, the left suprarenal gland, and the spleen ; its lower
part rests on the pancreas, the transverse meso-colon, and the
transverse colon. The two latter structures are supported
inferiorly by the underlying coils of small intestine, and together
with the pancreas, they form a ledge, sloping downwards and
forwards.

The Greater Curvature forms the anterior, or inferior, border
of the stomach. With the body in the horizontal position, it

19

290 THE ABDOMEN AND PELVIS

commences on the fundus (p. 289), cuts the left costal margin
at the tip of the ninth costal cartilage, descends not infrequently
almost to the umbilicus, and then ascends to the pylorus (vide
infra) ; in the erect posture it descends to the umbilicus, and
sometimes to a lower level. Along the greater curvature, the
two layers of peritoneum which clothe the stomach pass down-
wards to form the greater omentum, and on the left side they
pass backwards to the spleen as the gastro-splenic ligament.

The Lesser Curvature forms the upper or posterior border
of the stomach. It passes downwards and to the right from
the cardiac orifice to the pylorus, curving round the tuber
omentale of the liver. It can be mapped out on the surface by
a line, concave upwards and to the right, joining these two
points. In the erect posture this line becomes more nearly
J -shaped owing to the descent of the pylorus and the fixation
of the cardiac end of the stomach. Along the lesser curvature
the lesser omentum leaves the stomach and passes to the liver
and diaphragm.

The distal or pyloric portion of the stomach includes the
pyloric antrum, the pyloric canal, and the pylorus. The pyloric
antrum is a secondary dilatation of the stomach and is placed
proximal to the pyloric canal. The latter is tubular in shape
and is about one inch long. It communicates with the duodenum
through the pylorus.

With the body in the supine position and the stomach
moderately distended, the Pylorus lies on the transpyloric plane,
half an inch to the right of the middle line ; but when the erect
posture is adopted, it may sink down to the level of the third
lumbar vertebra. In Fig. 91, where the radiogram was taken
in the vertical position, the pylorus is seen at that level. At
a subsequent operation it was found that, with the change of
posture, it had ascended to the transpyloric plane.

The anterior surface of the pylorus lies in contact with the
liver, which hides it from view when the abdomen is opened.

The Position of the Stomach is subject to wide variations.
It is affected by (i) attitude, (2) respiration, (3) the tonus of the
anterior abdominal wall, and (4) its contents and those of the
small intestines and transverse colon. In addition, apart from
differences due to pathological conditions, there is a large range
of individual variation.

When the body assumes the erect posture, the postero-
inferior surface of the stomach slides downwards and forwards

THE ABDOMINAL CAVITY 291

on the sloping ledge which supports it. This movement is
rendered possible by the accompanying slight descent of the
diaphragm and the elasticity and loose attachment of the living

FIG. 91. — Normal Hypertonic Stomach. The black circle is on the umbilicus,
and the pylorus lies to the right side of the body of the third lumbar
vertebra.

peritoneum (p. 276). At the same time the pylorus undergoes
a similar change of position, which is permitted not only by the
two factors just mentioned, but also by the mobility of the
first inch of the duodenum. Owing to the constancy with which
this downward movement has been observed in radiograms

292 THE ABDOMEN AND PELVIS

taken with the body erect, the presence of the pylorus on the
transpyloric plane in such a photograph at once suggests the
probability of its immobilisation by adhesions in the pyloro-cystic
region (Fig. 92).

FIG. 92.— High Position of the Pylorus. At the subsequent operation
adhesions were found fixing the pylorus to the liver, gall-bladder, and
neighbouring structures. The black circle is on the umbilicus (fourth
lumbar vertebra).

Traube's Space corresponds to that part of the stomach
which is in direct contact with the diaphragm and under cover
of the costal margin. It is bounded (Fig. 150) above and to the
right by the inferior margin of the left lobe of the liver ; above,

THE ABDOMINAL CAVITY 293

by the lower margin of the left lung ; and behind, by the anterior
border of the spleen. Below, it is limited by the costal margin.

FIG. 93. Radiogram of Stomach, showing typical J outline. The black

circle lies on the umbilicus. The bismuth is well supported by the
muscular tonus, and, though somewhat low, the stomach is quite normal.
The transverse colon contains the fragmented bismuth of an earlier
bismuth meal.

The upper part of this area is overlapped by the left pleural
sac, but this does not alter the tympanitic stomach note which
is obtained on percussion. Enlargement of the left lobe of the

294 THE ABDOMEN AND PELVIS

liver encroaches on Traube's space from the right side ; enlarge-
ment of the spleen encroaches on it from the left side ; and
pleuritic effusions encroach upon it from above.

Structure of the Stomach. — The peritoneum gives the
stomach a complete serous coat, except along the curvatures
and also over a small area which is in direct contact with the
diaphragm, to the left of the cardia. The muscular coat consists
of three layers of involuntary muscle : an outer longitudinal, an
intermediate circular, and an inner oblique stratum. The
circular layer is greatly thickened at the pylorus to form a
sphincter, and may, in infants, give rise to congenital stenosis
of the pylorus, either by continued spasm or by actual
hypertrophy. The mucous coat is very thick and highly vascular,
and it is thrown into numerous folds, save when the stomach is
distended.

Radiographic Examination of the Stomach. — The normal
stomach gives a J -shaped shadow in radiograms taken in the
erect posture after a bismuth meal. The longer limb of the J
is vertical and lies to the left of the middle line. The bismuth,
being supported by the tonicity of the healthy stomach wall,
reaches a higher level in the longer than it does in the shorter
limb, which corresponds to the pyloric antrum (Fig. 93). In
atony of the stomach this support is withdrawn, and the fluid
adopts a uniform horizontal level.

In some radiograms a small cap-like shadow may be seen
immediately above the bismuth in the pyloric antrum and
separated from it by a clear area. This is due to the bismuth
contained in the first inch of the duodenum, and the clear area
corresponds to the pyloric canal, which is closed by the contraction
of the pyloric sphincter.

The Examination of the Living Stomach.— When the
abdomen has been opened, preferably in the median plane
above the umbilicus, the greater omentum is usually at once
exposed and the transverse colon may be seen shining through
it. The omentum is traced upwards till the greater curvature
is recognised, and the stomach may then be drawn downwards
and towards the left in order to permit the pylorus and the first
part of the duodenum to be examined. In the healthy stomach
the walls are firm, and the muscular thickening which marks the
pyloro-duodenal junction renders its recognition easy ; but in the
atonic stomach the walls are flaccid and thinner, and the pylorus
is more difficult to identify. In these cases the pyloric veins

THE ABDOMINAL CAVITY

295

which run across the anterior surface of the gut, serve as a guide
to the site of the pyloro-duodenal junction (Mayo). The
cardiac end and fundus can be examined, but owing to the

pIG> 94. — Stomach of a child, showing typical J outline. The black circle
is on the umbilicus. The pyloric antrum is somewhat distended.

fixation of the former they cannot easily be brought into view.
By drawing the stomach downwards and to the right, most of
the greater curvature can be inspected.

296 THE ABDOMEN AND PELVIS

In searching for the site of a perforated ulcer, the whole of
the antero-superior surface of the stomach and the anterior
surface of the first part of the duodenum must be examined.

If gastric contents are not found in the supra-colic com-
partment when the abdomen is opened, the postero-inferior
surface of the stomach must be exposed and examined. Before
doing so, the surgeon explores the epiploic foramen (of Winslow),
and if it is found closed by adhesions, the diagnosis of a perforated
ulcer leaking into the omental bursa may be made with some
confidence. In order to gain access to the postero-inferior
surface of the stomach, it is necessary to open into the omental
bursa. This can be done by carefully tearing through the
greater omentum about three inches to the left of the pylorus
and immediately below the gastro-epiploic vessels (p. 297).
The greater curvature is then turned forwards and upwards,
and, as a result, a large part of the postero-inferior surface of
the stomach can be both seen and felt through the opening in
the omentum. The cardia and the upper part of this surface
may be examined by tearing through the thinnest part of the
lesser omentum and everting the posterior surface of the stomach
through the opening thus made.

The Arterial Supply of the stomach is derived, either
directly or indirectly, from the cceliac (axis) artery, which arises
from the aorta just above the neck of the pancreas and at once
divides into (i) the left gastric, (2) the splenic, and (3) the
hepatic arteries.

1. The left gastric (coronary) artery passes upwards behind the
omental bursa to the cesophageal opening in the diaphragm. There it comes
into contact with the cardia, and having given off one or two ascending
branches to the oesophagus, it descends along the lesser curvature from left
to right. It usually divides into two parallel branches, which anastomose
with the right gastric (pyloric) artery.

2. The hepatic artery runs to the right along the upper border of the
pancreas, turns forwards round the right border of the omental bursa just
below the epiploic foramen, and reaches the first part of the duodenum. It
then turns upwards and ascends between the two layers of the lesser omentum
to the liver, in close relation to the bile-duct and portal vein (p. 314).

As the hepatic artery passes round the right border of the omental bursa,
it gives off the right gastric, which runs to the left along the lesser curvature
and anastomoses with the left gastric.

The gastro-duodenal artery arises from the hepatic at the upper border
of the first part of the duodenum. It descends behind the duodenum to its
lower border and there divides into the superior pancreatico-duodenal (p. 324)
and the right gastro-epiploic arteries. The latter passes to the left along the
greater curvature of the stomach and anastomoses with the left gastro-
epiploic.

3. The splenic artery runs to the left behind the omental bursa. It

THE ABDOMINAL CAVITY

297

has a tortuous course along the upper border of the pancreas and gives off
numerous branches to that viscus. On the anterior surface of the left kidney
it turns forwards between the two layers of the lieno-renal ligament and ends
in the spleen. - >

The short gastric and the left gaslro-epiploic arise from the splenic near its
termination and run forwards in the gastro-splenic ligament to the greater
curvature. The short gastric arteries are distributed to the fundus ; the
left gastro-epiploic passes to the right along the greater curvature and anasto-
moses with the right gastro-epiploic.

The stomach, therefore, is supplied directly from the cceliac artery by the
left gastric (coronary), and indirectly by the right gastric and gastro-epiploic
arteries from the hepatic, and the short gastric and left gastro-epiploic arteries

CEscphageal branch

Left gastric artery
Left inferior phrenic artery \
Cceliac glands

Lesser omer.tum, cut edges

Hepatic artery .,.

Coronary glands
/ Supra-pancreatic glands
/ Short gastric arteries

Splenic
branches

Left gastro-
epiploic artery

Right gastro-
epiploic artery
Gastro-epiploic gland

Greater omentum, cut edges
FIG. 95. — The Arteries and Lymph Glands of the Stomach. The course
of the lymph vessels is indicated by the arrows.

from the splenic (Fig. 95). The branches'which these vessels give off supply
the adjoining areas on both surfaces of the stomach and run at right angles
to its axis. Incisions in the stomach wall, for the purpose of excising gastric
ulcers, are made parallel to the vessels and, therefore, at right angles to the
long axis of the stomach.

The gastro-epiploic arteries lie between the two anterior layers
of the greater omentum. They are distinctly tortuous and are
placed about half an inch from the greater curvature. By this
arrangement the vessels are not subjected to pressure or
stretching when the stomach becomes distended.

298 THE ABDOMEN AND PELVIS

The Veins of the Stomach correspond to the arteries and
terminate in the portal vein, or in the two large vessels which
form it, viz. the superior mesenteric and the splenic. At the
cardia, the coronary vein anastomoses freely with the cesophageal
veins through the cesophageal opening in the diaphragm. In
this situation, therefore, an important communication occurs
between the portal and systemic circulations, and the veins at
the inferior end of the oesophagus consequently become enlarged
and varicose in portal obstruction. Their rupture gives rise to
haematemesis which may be the first sign of the condition.

The Nerve-supply of the Stomach is derived from both
vagi, and from sympathetic fibres which are associated with
the arteries and derived from the cceliac plexus. The sympathetic
nerves leave the spinal medulla in the mid-thoracic region
(T. 5-8). Referred pain frequently occurs in connection with
gastric disorders, and its site is most commonly the epigastrium.
The afferent impulses from the viscus are such that a " focus of
irritation " (Mackenzie) may be established in the mid-thoracic
region of the spinal medulla. As a result stimulation of the
terminal fibres of the afferent nerves which are connected with
the segment or segments involved produces an abnormal
response. In this way, localised hyperaesthetic or hyperalgesic
areas of skin and muscle may be explained. As the proximal
part of the stomach is supplied by the nerves which arise from
the higher segments of the spinal medulla, the situation of
these areas on the surface of the body should give an indication
of the site of the gastric lesion. Thus a hyperaesthetic area due
to an ulcer near the cardia should be in the upper part of the
epigastric region (T. 6, Fig. 72), whereas a similar area due to
a lesion near the pylorus should be in the lower part of the same
region (T. 8).

In the examination of patients suffering from gastric disorders,
the areas supplied by the posterior rami of the 5th-8th Th.
nerves should also be tested, as hyperaesthesia and hyperalgesia
of the skin of the back and the underlying sacro-spinalis muscle
are frequently present.

Examples of the viscero-motor reflex (p. 251) are also
commonly found in gastric mischief. They give rise to localised
areas of contraction in the upper parts of both recti (more
especially the left) and also in the sacro-spinalis.

The Lymph Vessels of the Stomach anastomose freely
with one another in its walls, but the lymph flow passes in

THE ABDOMINAL CAVITY 299

different directions from three areas, which may be roughly
indicated in the following way. A line is drawn from the highest
point on the fundus downwards and to the right to the pylorus
so as to divide the organ into an upper, larger, and a lower,
smaller area. The latter is again subdivided by a line drawn
upwards from the middle of the greater curvature.

The primary lymph glands of the upper area are (i) the
coronary group, and (2) the supra-pyloric lymph gland. The
coronary group lies between the two layers of the lesser omentum,
and is closely associated with the left gastric vessels, while the
lymph stream flows in the same direction as the coronary vein
as far as the cceliac artery. The supra-pyloric lymph gland lies
immediately above the pylorus in association with the right
gastric vessels, and the lymph stream in this small area follows
the course of the hepatic artery. From both the efferents pass
to the cceliac lymph glands, which therefore constitute the
secondary or main group for the upper area of the stomach. They
lie around the trunk of the cceliac (axis) artery and belong to
the pre-aortic group (Fig. 95).

The primary lymph glands of the right lower area lie between
the two anterior layers of the greater omentum in relation to
the right gastro-epiploic vessels. They form the inferior gastric
chain, and those near the pylorus are termed the sub- and retro-
pyloric glands. Their efferents accompany the gastro-duodenal
and hepatic arteries and end in the cceliac group.

The primary lymph glands of the left lower area lie along the
upper border of the body and tail of the pancreas. Their affer-
ents from the stomach reach them by passing through the gastro-
splenic ligament ; their efferents terminate in the cceliac group.

The direction of the lymph flow from the three areas
described above is of great practical importance in connection
with malignant disease of the stomach. This condition usually
begins near the pylorus and spreads upwards along the lesser
curvature in the direction of the lymph flow. Its removal
therefore necessitates the excision of as much of the lesser
curvature as possible, and a not inconsiderable portion of the
greater curvature as well.

Owing to the direction of the lymph stream, the disease
rarely spreads to the duodenum, and therefore only its first
inch or so requires to be removed. In addition, the coronary,
supra-pyloric, and inferior gastric lymph glands must be taken
away in order to minimise the chances of recurrence.

300 THE ABDOMEN AND PELVIS

Pylorectomy.— The feasibility of pylorectomy or partial
gastrectomy having been recognised, the first step in the
operation consists of the division of the lesser omentum near
the liver. It is then stripped away with gauze in a downward
direction, care being taken to avoid injury to the important
structures in its right free margin. The first part of the
duodenum is separated from the portal vein and the head of the
pancreas (Fig. 87), and rendered freely movable. At the
same time the gastro-duodenal (or right gastro-epiploic) and
the right gastric vessels are exposed, ligatured, and divided.
The duodenum is then cut through between two clamps, about
i or i£ inches beyond the pylorus, and its distal stump is
invaginated. Next, the stomach is drawn downwards and to
the left, and the left gastric vessels are ligatured close to the
cardia. The lower blade of a clamp is now passed through the
greater omentum below the gastro-epiploic vessels and carried
upwards through the omental bursa behind the stomach. The
superficial blade follows anteriorly, and the clamp is then fixed
in such a way as to remove as much of the lesser curvature and
as little of the greater as may be necessary. After ligature of
the left gastro-epiploic vessels, the area thus mapped out is
removed along with its associated lymph glands. The proximal
cut surface of the stomach is closed, and a posterior gastro-
enterostomy completes the operation.

In the course of malignant disease of the lesser curvature, the
cceliac lymph glands are involved secondarily to the coronary
and supra-pyloric, and the infection may be carried down into
the pelvis by retro-peritoneal lymph vessels. Secondary
deposits frequently occur in the liver. They may be due to the
primary growth ulcerating into the gastric veins and the passage
of cancerous emboli along the portal vein ; or the spread may
be by the lymph vessels. In this case the coronary lymph
glands become obstructed by the disease, and, as a result, stasis,
or a reversal of the direction of the flow, occurs in the lymph
vessels which they receive from the liver.

If cancer cells pass along the efferents of the cceliac lymph
glands and enter the thoracic duct, they may subsequently
infect the left lower anterior group of the deep cervical lymph
glands (p. 133); which are sometimes found enlarged in malignant
disease of the stomach. From the thoracic duct the cells may
pass into the left innominate vein and so be deposited in any
part of the body.

THE ABDOMINAL CAVITY 301

Gastro-Enterostomy. — When the stomach fails to empty
itself efficiently owing to pyloric obstruction, atony, or for any
mechanical reason, the condition may be improved by the
operation of gastro-enterostomy, with or without additional
complete closure of the duodenum. In the presence of gastric
or duodenal ulceration associated with hyperchlorhydria, the
same operation may be performed to provide a new outlet from
the stomach, thus giving to the ulcer the necessary rest from
irritation ; at the same time it permits the bile to enter the
stomach and neutralise the hyperacid gastric contents.

The operation of choice is the method known as " Posterior,
no loop, antiperistaltic gastro - jejunostomy." When the
abdomen has been opened, preferably in the median plane,
the duodeno-jejunal flexure and the first few inches of the
jejunum must be identified. The greater omentum and
transverse colon are drawn out of the abdomen with the left
hand, until the transverse meso-colon is rendered tense, and
the latter is then traced backwards to its attachment with the
right hand. On the left side of the vertebral column and
immediately below the transverse meso-colon the fingers
encounter the first coil of the jejunum ; this is withdrawn
through the wound, and in the process the duodeno-jejunal
flexure is recognised by its fixation. The surgeon then makes
an opening in the greater omentum below the gastro-epiploic
vessels, and, passing his left hand into the omental bursa, holds
the transverse meso-colon tense. With his right hand he then
divides the latter fold for at least two inches in a vertical
direction. Through this opening, which is made to the left of
the middle colic artery (p. 338), the surgeon passes the proximal
piece of the jejunum into the omental bursa with his right hand.
Maintaining the gut in its original direction, he draws it out
with his left hand through the opening in the greater omentum
(Stiles). A long intestinal clamp is applied along the extended
loop of bowel, after it has been emptied by massage. At this
stage the transverse colon and greater omentum are replaced
in the abdominal cavity and the postero-inferior surface of the
stomach is turned out through the opening in the latter. The
site for anastomosis is selected, preferably the most dependent
part of the greater curvature, and a second clamp is applied
transversely to this area of the stomach. The anastomosis is
carried out, and finally allowed to drop back into the omental
bursa. After the opening in the greater omentum has been

302 THE ABDOMEN AND PELVIS

closed, the transverse colon is again lifted out of the abdomen
and the jejunum is lightly drawn upon until the anastomosis
appears at the opening in the transverse meso-colon. The
margins of this opening are stitched to the posterior wall of the
stomach or to the jejunum. This hinders the latter from being
retracted through the opening and prevents the occurrence of
hernia of small intestine into the omental bursa.

It is important to remember that during this or any other
intestinal anastomosis the haemorrhage from the wounded
bowel is controlled by those sutures which pierce all three coats ;
they must therefore be kept taut until the suturing is completed.
The reasons for the choice of the method described above may
be briefly stated as follows :

1. The posterior anastomosis is preferable because, in the
conditions for which the operation is performed, the most
dependent part of the stomach is on the postero-inferior surface
near the greater curvature.

2. The union of the proximal part of the jejunum to the
stomach without any loop is very rarely followed by the formation
of kinks or spurs.

3. The original direction and position of the first coil of the
jejunum, which is directed towards the left, are preserved ; the
anastomosis is therefore antiperistaltic.

4. The anastomosis is carried out through an opening in
the greater omentum. While it is being established, all the
viscera except those parts immediately concerned in the suturing
are within the abdominal cavity. Thus the more movable
jejunum is approximated to the less movable stomach (Stiles).

5. Both the hands of the assistant are left free.

It may sometimes be found impossible to perform the
posterior operation, if adhesions, which may obliterate the
omental bursa, render the stomach less freely movable or if
the transverse meso-colon is too short. Under these circum-
stances the anterior method of anastomosis is adopted.

Anterior Gastro-Enterostomy. — This route necessitates
the use of a loop, as it is impossible to bring the proximal end
of the jejunum into contact with the anterior surface of the
stomach in a satisfactory manner. The duodeno-jejunal flexure
is found and the gut is traced distally for eighteen or twenty
inches. A loop of jejunum is then brought upwards in front
of the greater omentum and sutured to the anterior surface of
the stomach near the greater curvature. The loop is intentionally

THE ABDOMINAL CAVITY 303

made longer than is necessary; in order to guard against
subsequent obstruction, because, as a general rule, the patient
puts on weight after this operation, and much fat may be
deposited in the greater omentum.

Occasionally in loop operations a kink or spur may form
and obstruct the outlet into the distal limb of the anastomosis.
The bile collects in the proximal limb and together with the
food is prevented from passing onwards. If the pylorus is
patent, this may set up a vicious circle. It is therefore usual to
carry out entero-anastomosis in addition to the loop operations,
and the jejunum on the proximal side of the gastro-enterostomy
is joined to the jejunum on the distal side. This allows the bile
to short-circuit into the small intestine at some distance from
the gastric anastomosis.

After this second step, peptic ulceration occasionally occurs
in those portions of the jejunum between the gastric anastomosis
and the entero-anastomosis, since in this area the hyperacid
chyme is not neutralised by the alkaline bile.

Development of the Stomach and the Omental Bursa (Lesser Sac). —

The first indication of the stomach is a fusiform dilatation, which appears
in the caudal part of the foregut during the fourth week. It is median in
position and is moored to the anterior and posterior abdominal walls by a
ventral and a dorsal mesentery. The dorsal aspect of the stomach grows
more rapidly than the ventral, and the lower or pyloric end is first thrust
forwards and is then rotated to the right side. In this way what was origin -
nlly the left surface of the stomach now becomes anterior, and it carries the
left vagus nerve with it. The rotation of the stomach produces a fossa
between it and the dorsal wall ; this is the site of the omental bursa.

The lower part of the dorsal mesentery of the stomach grows rapidly
and sags downwards into the abdomen, converting the fossa into a bursal
sac which has a widely open mouth looking to the right. At the same time
the mesentery of the duodenum shortens and then disappears, so that the
lower margin of the epiploic foramen becomes defined.

The spleen develops as a condensation of the mesoderm between the two
layers of the dorsal mesentery in its upper part and divides it into the gastro-
splenic and lieno-renal ligaments.

The Duodenum extends from the pylorus to the duodeno-
jejunal flexure. It forms a C-shaped bend, which encloses the
head of the pancreas, and its total length is about ten inches.

When the body is in the supine position, the Superior or
First Part of the duodenum passes backwards and slightly
upwards from the pylorus to the neck of the gall-bladder, and
is in relation to the inferior surface of the liver. When the
body is in the erect position, this part passes vertically upwards
owing to the descent of the pylorus (p. 290), and the level of the

304 THE ABDOMEN AND PELVIS

first flexure of the duodenum sinks downwards,, sometimes, to
the second lumbar vertebra. The proximal inch or less of the
first part is freely movable as it is invested by the same two
layers of peritoneum as enclose the stomach. Its upper border
is related to the lesser omentum and the right gastric (pyloric)
artery, and its lower border to the greater omentum and the right
gastro-epiploic artery. Behind it lies a small recess of the
omental bursa. The distal inch or more of this part receives
from the peritoneum only an anterior covering so that its range
of movement depends entirely on the elasticity or looseness of
its peritoneal coat. Its posterior, or postero-medial, surface is
in immediate relation to the bile-duct, portal vein, and gastro-
duodenal artery, while the inferior vena cava is separated from
it by these structures and by some areolar tissue (Fig. 87).

The whole of the antero-lateral surface of the first part of
the duodenum lies in the supra-colic subdivision of the peritoneal
cavity. This aspect is the commonest site of duodenal ulceration,
and perforation will primarily infect the supra-colic compartment.
On the other hand, perforation of an ulcer on the postero-medial
surface will, if it is situated close to the pylorus, at once involve
the omental bursa; but if it is placed more distal ly, the infection
will be retroperitoneal and may pass up along the inferior vena
cava to the extra-peritoneal subphrenic area (p. 310).

As the closure of such perforations results in marked narrowing
of the lumen of the gut, gastro-enterostomy is usually performed
lest complete obstruction should follow.

Mayo has suggested that the frequency with which duodenal
ulcer occurs on the antero-lateral wall is determined by the fact
that the over-acid chyme, as it is squirted through the pylorus,
incessantly impinges on this wall and produces repeated minute
traumata. It has also been urged that the area in question is
supplied by a small branch from the hepatic or gastro-duodenal,
and that its terminal twigs are end-arteries, i.e. do not anastomose
with other vessels in the neighbourhood. Thrombosis in this
artery, therefore, would in all probability give rise to necrosis
of the area supplied by it. In childhood, however, the anasto-
mosis is complete.

The Descending or Second Portion passes downwards
from the neck of the gall-bladder along the medial border of
the right kidney to the level of the third lumbar vertebra, lying
in front of the hilum of the kidney and the commencement of
the ureter. It is crossed anteriorly, in its lower part, by the

THE ABDOMINAL CAVITY

transverse colon, which at this point may or may not possess a
mesentery, and in this situation the peritoneum, which gives it
an anterior covering only, is lifted from its surface. Above the
transverse colon, the second part of the duodenum lies in the

Epiploic foramen

Cystic artery
Portal trem
Hepatic artery
Lesser oir.entum

Bile-duct
-— Right gastric artery

— Right suprarenal gla

— Peritoneum, cut edg(

Head of pancreas

— Peritoneum, cut edg<
— — Inferior vena cava

— Right ureter

FIG. 96. — Exposure of the Terminal Part of the Bile-Duct. The peritoneum
has been incised along the right sides of the right colic flexure and of the
duodenum. The duodenum and the flexure have been turned downwards
and to the left, exposing the posterior surface of the head of the pancreas.
A small window has been made in the anterior layer of the lesser omentum
at its right border.

supra-colic compartment ; below, it lies in the right infra-colic
compartment and is related laterally to the ascending colon
(Fig. 88). The head of the pancreas and the terminal part of
the bile-duct are related to its medial side.

Owing to its peritoneal relations, the second part of the

20

3o6 THE ABDOMEN AND PELVIS

duodenum is fixed in position. In retro-peritoneal exploration
of the lower end of the bile-duct (p. 316) it must be rendered
movable so that it can be turned downwards, forwards, and to
the left. This can be effected by incising the peritoneum over
the right kidney along the lateral border of the upper end of
the second part of the duodenum (Kocher).

If necessary, this incision may be extended downwards
along the lateral margin of the right colic flexure and the
ascending colon. The duodenum and the ascending colon can
then be lifted off the right kidney and turned to the left (Fig.
96). In freeing the duodenum, the right renal vessels are
exposed as they lie in close relation to its posterior surface
(see also p. 316).

The Horizontal or Third Part of the duodenum runs
transversely to the left in front of the ureter, the inferior vena
cava, and the aorta to end at the left side of the third lumbar
vertebra. It lies behind the peritoneum in the right infra-colic
compartment, but at its termination it is crossed by the root
of the mesentery. The superior mesenteric vessels and accom-
panying nerves run downwards over its anterior surface and
enter the root of the mesentery (Fig. 88). This relationship
is of great importance in the condition of enteroptosis. The
weight of the small intestine, hanging down into the pelvis,
stretches the superior mesenteric artery tightly across the third
part of the duodenum, producing obstruction which may lead
to acute dilatation of the stomach.

The head of the pancreas lies in contact with the upper
border of this part of the duodenum ; in the groove between
these two structures the inferior pancreatico-duodenal artery
(p. 323) runs towards the right.

The Ascending or Fourth Part of the duodenum runs
upwards, and slightly to the left, to the duodeno-jejunal flexure.
Its left side is covered by the peritoneum on the posterior wall
of the left infra-colic compartment, while its right side is in
contact with the pancreas and the aorta.

At the left side of the second lumbar vertebra the fourth part
of the duodenum bends sharply forwards, downwards, and to
the left to form the Duodeno-Jejunal Flexure. This bend lies
in contact with the inferior surface of the pancreas immediately
below the root of the transverse meso-colon. It can be found
by passing the hand backwards behind the greater omentum to
the posterior abdominal wall, and then carrying it upwards along

THE ABDOMINAL CAVITY 307

the left side of the vertebral column until the fingers are caught
in the loop of the flexure (see also p. 301).

Duodenal Peritoneal Fossae. — In the region of the duodeno-jejunal
flexure there are several inconstant fossae which require description, as they
may be responsible for strangulated retro-peritoneal hernias.

1. The superior duodenal fossa is bounded in front by a free crescentic
margin, which extends to the left for about one inch from the duodeno-jejunal
flexure. Its mouth looks downwards, while its cavity passes upwards towards
the pancreas. The upper part of the inferior mesenteric vein may lie along
its lateral border and project into its anterior wall.

2. The inferior duodenal fossa is at a lower level and its mouth looks
upwards. Its anterior margin is about one inch long and is attached medially
to the fourth part of the duodenum.

3. The paraduodenal fossa, when present, is larger than the others. Its
mouth looks medially, and its free crescentic margin, which may be two inches
long, may unite the lateral extremities of the free borders of the superior and
inferior fossae when they are also present. The inferior mesenteric vein runs
upwards in its anterior wall, and the ascending branch of the left colic artery
(p. 340) may occupy a similar position or may lie along its lateral margin.
When a hernia enters this fossa it carries its sac downwards and laterally
behind the posterior parietal peritoneum and the vessels already mentioned,
but in front of the left ureter or kidney. Should strangulation occur, great
care must be taken in dividing the neck of the sac lest the inferior mesenteric
vein or the left colic artery be injured ; the neck of the sac should be incised
in a downward direction, parallel to the vessels.

4. The retro-duodenal fossa lies behind the flexure on the anterior aspect
of the aorta and vertebral column. Its mouth looks towards the left, and
so when all four fossae are present their margins form a continuous circular
edge.

Surface Marking of the Duodenum. — The duodenum can now be
mapped out on the surface. The first flexure lies a little above the trans-
pyloric plane at a distance of 1^-2 inches from the middle line. The second
portion descends medial to the right lateral line and extends a little below
the subcostal plane. The third port-ion crosses the middle line horizontally,
and the fourth ascends to the duodeno-jejunal flexure, which just reaches
the transpyloric plane, one inch to the left of the middle line.

The Liver occupies most of the right hypochondriac and
epigastric regions. It is roughly pyramidal in shape, its base
being directed to the right and its apex lying behind the fifth
left intercostal space, half an inch medial to the left lateral line.

The Anterior Surface of the liver is related to both halves
of the diaphragm, and in the middle line it lies in direct contact
with the anterior abdominal wall, occupying the upper part of
the subcostal angle (Fig. 97). In this region it can readily be
examined by palpation and percussion. It is partially over-
lapped by the right lung and pleura and, under cover of the left
costal margin, by the left pleura and, to a slight extent, by the
pericardium (Fig. 97). Its upper border can be mapped out
by a line drawn from a point on the fifth right rib half an inch
medial to the right lateral line, to a second point in the fifth

20 «

3o8

THE ABDOMEN AND PELVIS

left interspace half an inch medial to the left lateral line. This
line curves downwards slightly at its centre and crosses the
median plane at the xiphi-sternal junction. The inferior border
of the anterior surface of the liver extends upwards from the
tip of the tenth right to the tip of the eighth left costal cartilage,
crossing the middle line at the transpyloric plane, and then

FIG. 97. — Surface Relations of the Liver, Stomach, Lungs, Heart

and Pleural Sacs.

Blue line = outline of lung. Dotted blue line = lines of pleural reflection.
Fine black line = heart and great vessels. Heavy black line — liver. Dotted
black line = stomach.

ascends to join the upper border. The right border of this
surface can be indicated by joining the right extremities of the
superior and inferior borders by means of a line which is gently
convex to the right.

Tropical abscess of the liver may point on the anterior
surface, and can then be exposed by an oblique incision just
below the right costal margin. If necessary, portions of the

THE ABDOMINAL CAVITY 309

eighth and ninth costal cartilages may be resected, but the
seventh must be left in situ on account of the danger of opening
into the right pleural sac (Fig. 97).

The Right Lateral Surface of the liver lies under cover of
the seventh, eighth, ninth, tenth, and eleventh ribs, and extends
a little below the costal margin in the mid-axillary line. It
lies in contact with the diaphragm, and is overlapped by the
right pleura in rather more than its upper two-thirds (Fig. 151).
It is entirely covered by peritoneum, and a recess of the
greater sac extends upwards between it and the diaphragm.

Solitary abscess of the liver is commonly situated near
the upper surface of the right lobe, and as it enlarges it displaces
the diaphragm in an upward direction. Evacuation of a liver
abscess is carried out from the right side by means of a curved
incision, convex downwards, which is planned so as to expose the
eighth and ninth ribs and the adjoining intercostal spaces. The
flap, which consists of skin and fasciae, is turned upwards, and
a portion of one or both of the ribs exposed is resected sub-
periosteafly. The periosteum and the costal pleura on its
deep surface are then incised. Usually the pleural sac in this
situation is found obliterated by adhesions, but if not, the cavity
must be shut off by suturing the upper cut margin of the costal
pleura to the diaphragmatic pleura. It will probably be
necessary to ligature the intercostal vessels of the space below
the rib excised. An incision is then made through the diaphragm
into the liver, to which it is generally firmly adherent. The
adhesions, which are due to perihepatitis, entirely obliterate
the peritoneal recess, which separates the liver from the
diaphragm. Sinus forceps can now be thrust through the liver
substance into the abscess cavity. A drainage tube may be
inserted and brought to the surface through a stab wound in
the flap, so that the original incision can be closed.

The Superior Surface of the liver is in contact with the dia-
phragm, and both are covered by peritoneum. It is related above
to both lungs and pleural sacs, and to the heart and pericardium.

When a liver abscess ruptures spontaneously it usually does
so through the superior surface, after it has become adherent
to the diaphragm. It thus enters the pleural sac and gives rise
to an empyaema. It sometimes happens that adhesions have
fixed the basal surface of the lung to the diaphragmatic pleura,
and in these cases the pus ruptures into the lung, being sub-
sequently evacuated by coughing.

206

3io THE ABDOMEN AND PELVIS

The Posterior Surface of the liver is in contact with the
inferior vena cava and the diaphragm, and lies in front of the
lower thoracic vertebrae. The peritoneum on the superior
surface is not continued over the posterior surface, but is reflected
on to the diaphragm, forming the upper or anterior layer of the
coronary ligament. Since the peritoneum on the inferior surface
of the right lobe is reflected on to the kidney as the hepato-renal
(posterior layer of coronary) ligament, the right half of the
posterior surface is devoid of any peritoneal covering. It is
known as the " bare area " and is in direct contact with the
diaphragm. The bare area of the liver is the site of extra-
peritoneal subphrenic abscesses, which result from the upward
spread of .pus from retro-peritoneal abscesses on the right side
of the abdomen.

The Inferior Surface of the liver is divided into a large
right and a smaller left lobe by the fossa for the umbilical vein,
which extends from the inferior border of the liver to the left
extremity of the porta hepatis (transverse fissure}. The porta is
placed transversely on the inferior surface, and its margins
receive the attachment of the lesser omentum. From its right
extremity the fossa for the gall-bladder extends forwards to the
inferior border of the liver. In this way a rectangular area is
defined, which lies in contact with the pylorus and the com-
mencement of the duodenum.

The inferior surface of the left lobe is related to the antero-
superior surface of the stomach. The right lobe is related to
the right kidney posteriorly, to the right colic flexure anteriorly,
and to the gall-bladder and the duodenum medially.

Tropical abscess of the liver occasionally points on the
inferior surface, and may rupture into the right colic flexure.

Blood-vessels of the Liver. — The liver receives its blood-
supply from both the hepatic artery (p. 296) and the portal vein,
and after circulating through the liver the blood is returned
to the inferior vena cava by the hepatic veins.

The Portal Vein brings to the liver the blood which has
already passed through the capillaries of (i) the whole abdominal
alimentary canal, except the lower end of the rectum and the
anal canal, (2) the spleen, (3) the pancreas, and (4) the gall-
bladder. Portal obstruction, therefore, whether due to direct
pressure on the portal vein or its branches, or to backward
pressure from the heart, will produce venous congestion in all
these organs, with enlargement of the spleen and gastro-intestinal

THE ABDOMINAL CAVITY 311

disturbance. Serum transudation occurs (i) into the stomach,,
giving rise to the morning sickness of alcoholic cirrhosis ; (2) into
the intestines, causing diarrhoea; and (3), .into the peritoneal
cavity, giving rise to ascites.

Certain channels of anastomosis exist between the portal and
the systemic circulation, (i) At the lower end of the oesophagus,
the left gastric veins communicate with the cesophageal veins.
In portal obstruction these veins become varicose and may
rupture, causing hsematemesis. (2) At the lower end of the
rectum the superior, middle, and inferior haemorrhoidal veins
communicate freely. They become varicose in portal obstruction
and give rise to internal haemorrhoids, which may act as a
" safety valve " to the venous congestion. In cases of internal
haemorrhoids the possibility of portal obstruction must be
excluded before operation is advised. (3) The connections of
the para-umbilical vein have been discussed on p. 243. (4) The
lumbar veins on the posterior abdominal wall communicate
with the mesenteric veins. (5) The veins on the " bare area "
of the liver communicate with those on the inferior surface of
the diaphragm.

These natural routes seldom suffice to establish compensation,
and the Talma- M orison operation aims at the production of
artificial anastomoses between the portal and the systemic
veins. The opposing peritoneal surfaces of the liver, spleen
(portal circulation), diaphragm, and anterior abdominal wall
(systemic circulation) are greatly irritated to encourage the
formation of adhesions. In addition, the greater omentum
(portal circulation) is fastened to the peritoneum of the anterior
abdominal wall (systemic circulation) by a series of stitches.

Development of the Liver. — The liver is developed from a hollow
bud which grows upwards from the duodenum into the septum transversum
(the forerunner of the diaphragm). The bud subdivides into two, of which
one forms the gall-bladder and cystic duct and the other gives rise to the liver
substance. The liver grows downwards with great rapidity into the ventral
mesentery of the stomach, which it subdivides into the falciform ligament
and the lesser omentum. The proximal end of the original outgrowth
remains as the bile-duct and retains its connection with the duodenum.

The Gall-Bladder lies in a fossa on the inferior surface
of the right lobe of the liver. It is covered on its inferior surface
by peritoneum which binds it closely to the liver, but its fundus
may project beyond the lower margin of that organ and it then
receives a complete investment. The long axis of the gall-

312 THE ABDOMEN AND PELVIS

bladder is directed upwards, backwards, and medially towards
the porta (hilum) of the liver, where it becomes narrowed to
form the cystic duct. On its medial side and inferiorly lie
the first part and the commencement of the second part of the
duodenum ; below and to its lateral side it is in relation to
the right colic flexure and the commencement of the transverse
colon. After prolonged cholecystitis, it may be united to these
viscera by dense adhesions, and occasionally gall-stones may
ulcerate through its wall and be discharged into the intestinal
canal.

The cystic artery arises from the right terminal branch of the
hepatic and runs to the right, crossing in front of the common
hepatic duct. It divides into a superficial branch which
supplies the inferior surface of the gall-bladder, and a deep
branch which ramifies between its upper surface and the liver.
The cystic vein joins the vena portse.

Cholecystectomy. — Ligation of the cystic artery and duct
constitutes the first step in cholecystectomy. This is carried
out close to the origin of the vessel in order to prevent the
haemorrhage which would otherwise occur when the gall-bladder
is stripped from its bed. The peritoneum is then incised along
the inferior surface of the gall-bladder and separated from it.
After the viscus has been freed from the liver and excised, the
cut edges of the peritoneum are united over the exposed area
of liver substance.

Pancreatitis may accompany or follow cholecystitis, and
produce jaundice by pressure on the bile-duct. On this account
the gall-bladder is retained if at all possible, for cholecyst-
enterostomy may subsequently be necessary in order to relieve
the condition.

The Nerve-Supply of the Gall-Bladder is derived from
(1} the right phrenic (C. 3, 4, and 5), (2) the vagus, and (j) the
cceliac sympathetic plexus (Th. 7-9). The repeated attempts
of the gall-bladder to expel calculi into the cystic duct give rise
to referred pain, which is commonly felt in the right half of the
epigastrium, but severe pain is sometimes experienced over
the right shoulder or in the posterior cervical region. In both
the latter cases the afferent stimulus does not pass via the
sympathetic but by the phrenic nerve. The viscero-motor
reflex is frequently present in the upper part of the right rectus.
These attacks of biliary colic cease when the stone has accom-
plished its journey along the bile-duct into the duodenum, or

THE ABDOMINAL CAVITY 313

when the expulsive efforts fail and the stone falls back again
into the gall-bladder.

As the centres for the stomach and the, gall-bladder occupy
the same segments in the spinal medulla, and since both
viscera are supplied by the vagus, the symptoms which are
due to viscero-sensory and viscero-motor reflexes are very
similar in the two cases. Thus in ulceration of the stomach
the stimulation of the gastric terminals of the vagus causes
vomiting on the ingestion of food. In diseases of the gall-
bladder the afferent impulses along the vagus may set up a
" focus of irritation " in the medulla oblongata, so that the
simple stimulus of the gastric branches of the same nerve,
caused by the ingestion of food into the healthy stomach, may
elicit an abnormal response from the irritated centre, and emesis
results. Errors in diagnosis, therefore, are not infrequent, and
are easily explained in the light of the nerve-supply of the two
viscera.

The Fundus of the Gall-Bladder may be mapped out on
the surface in the angle between the right rectus and the costal
margin, with the patient in the supine condition. When the
gall-bladder becomes distended it enlarges downwards and
medially, giving rise to a movable tumour, which may be mistaken
for a floating kidney. Owing to its peritoneal connection to
the liver, the tumour always returns to its first position after
being displaced by manipulations, and this feature should suffice
to determine the diagnosis.

The mucous membrane lining its interior is so rich in mucus-
secreting glands that, when the cystic duct is obstructed by an
impacted calculus, the gall-bladder may become dilated and form
a mucocele. This obstruction offers no hindrance to the free
passage of bile into the duodenum, and therefore cholecystitis
may be present without an associated jaundice.

In the event of permanent occlusion of the bile-duct from
pancreatitis, malignant disease, or stricture, the intense jaundice
and the itching which it causes may be relieved by the operation
of cholecyst-enterostomy. If possible the duodenum is utilised,
but, failing it, good results follow the anastomosis of the gall-
bladder with the stomach, right colic flexure, or the transverse
colon. The operation is carried out on the same lines as gastro-
enterostomy or entero-anastomosis.

The Cystic Duct is about i| inches long, but as it is folded
upon itself in an S-shaped manner, its union with the hepatic

314 THE ABDOMEN- AND PELVIS

ducts occurs quite close to the neck of the gall-bladder. The
lining mucous membrane is redundant and projects into the
lumen as a spiral fold, the valve of Heister, which obstructs the
passage of a probe except when the duct is greatly enlarged
owing to the passage of stones or to intermittent obstruction
of the common duct.

The cystic duct may be examined by tracing the gall-bladder
upwards, backwards, and medially to the porta hepatis, where
it is associated with one or two lymph glands.

The Common Hepatic Duct is a short trunk formed by
the union of the right and left hepatic ducts in the porta (hilum)
of the liver.

The Bile-Duct is formed immediately below the porta of
the liver by the union of the cystic with the common hepatic
duct. It is three to four inches long and passes downwards (i)
in the lesser omentum, (2) behind the first part of the duodenum,
and (3) postero-lateral to the head of the pancreas, to terminate
by opening into the second part of the duodenum.

The first or supra -duodenal portion of the bile-duct
is about ij inches long. It descends in the right border of the
lesser omentum, lying in front of the portal vein and to the right
side of the hepatic artery. Several lymph glands are closely
related to the bile-duct at its commencement and near its
termination, and they are apt to become enlarged in septic
conditions of the gall-bladder and bile-duct, and in malignant
disease of the lesser curvature of the stomach and of the pancreas.
When enlarged they may be mistaken for impacted gall-stones.

The surgical approach to the gall-bladder (p. 252) is planned
so as to afford sufficient exposure for a thorough examination
of the bile-passages as well. After the gall-bladder has been
dealt with, the index finger of the left hand is passed along its
inferior surface and introduced into the epiploic foramen (of
Winslow). If the hepato-colic ligament (p. 279) is present, it
must be divided to improve the access. The supra-duodenal
portion of the bile-duct may then be palpated between the left
forefinger and thumb, and if a stone is detected it should be
" milked " back along the cystic duct into the gall-bladder.
When the stone is impacted, the duct is hooked forwards to
the surface and incised longitudinally to permit of its extraction.
Advantage may be taken of this opening to pass a probe upwards
to explore the hepatic ducts, and downwards to the ampulla
of Vater.

THE ABDOMINAL CAVITY 315

The second or retro -duodenal part of the bile-duct

descends behind the first part of the duodenum, to the right of
the portal vein and in front of the inferior vena cava (Fig. 87).
Its length, usually about one inch, depends upon the upward
extent of the head of the pancreas. In order to examine this
part of the bile-duct the finger is again introduced into the
epiploic foramen and the thumb is placed on the antero-lateral
aspect of the first part of the duodenum. When the two are
squeezed together the presence of one or more impacted stones
can be recognised. It may be necessary to expose the second
part of the bile-duct (p. 306), but the stone can sometimes be
manipulated downwards into the duodenum, or upwards into
the first part of the bile-duct, or it may even be made to retrace
its course along the cystic duct into the gall-bladder.

The third or pancreatic portion of the bile-duct passes
downwards and slightly to the right and terminates by piercing
the postero-medial aspect of the second part of the duodenum
about its middle. It is about i J inches long and lies in a groove
on the postero-lateral aspect of the head of the pancreas, being
sometimes embedded in its substance. It is separated from
the anterior surface of the inferior vena cava by some fibrous
tissue. The superior pancreatico-duodenal artery lies first to
the right side of the bile-duct and then crosses in front of its
lower end. Very often, however, the artery passes behind the
duct, and in these cases may give rise to haemorrhage when
the pancreatic portion is being exposed. In this operation
haemorrhage may also be caused by injury of a vein, which issues
from the posterior aspect of the head of the pancreas and runs
upwards and medially, along the medial side of the pancreatic
part of the bile-duct, to join the portal vein. As the bile-duct
enters the wall of the duodenum it is joined, on its left side, by
the pancreatic duct, and the two open into a dilatation of the
canal — the ampulla of Vater — which lies partly within the wall
(Fig. 98). The opening from the ampulla into the duodenum is
placed on the duodenal (bile) papilla, and is so small that gall-
stones, which have passed along the whole length of the cystic
and bile ducts, often become impacted in the ampulla. When
this occurs, the pancreatic secretion as well as the bile may be
prevented from entering the duodenum, unless a communication
exists between the main pancreatic and the accessory duct
(p. 319). In addition, septic infection, which commonly exists
in the presence of gall-stones, is apt to spread along the pancreatic

316 THE ABDOMEN AND PELVIS

duct and cause pancreatitis. The bile-duct narrows slightly
just before opening into the ampulla of Vater, and stones may
become impacted in this situation, but in this case the pancreas
is not so likely to be affected.

Considerable variation exists in the method of termination oj
the pancreatic and bile ducts, (i) The two unite, but the ampulla
of Vater is absent. (2) The two open independently into the
duodenum, either on the summit of a small papilla, or at the
bottom of a slight depression. In this case the impaction of a
stone in the bile-duct does not produce symptoms of pancreatic
obstruction (Fig. 98).

The pancreatic part of the bile-duct may be examined by

in

IV

FIG. 98.

-Diagrams to show the Varying Modes of Termination of the
Bile-Duct and the Pancreatic Duct.

I shows the normal arrangement, with the accessory pancreatic duct
opening independently into the duodenum at a higher level.

gently pressing the second part of the duodenum against the
right side of the vertebral column, but if the head of the pancreas
is enlarged and hard owing to chronic pancreatitis, great difficulty
may be experienced in determining whether a stone is present
or not. To expose this part of the duct, it is necessary to free the
second part of the duodenum and turn it forwards and to the
left (p. 306). At the same time the head of the pancreas is
carefully separated from the inferior vena cava and exposed to
view. The bile-duct is then found at the upper border of the
first part of the duodenum, traced downwards and freed from
the pancreas. At this stage some haemorrhage may occur from
cut branches of the superior pancreatico - duodenal vessels.
After removal of the stone, satisfactory drainage of the region

THE ABDOMINAL CAVITY 317

can be obtained by bringing out a tube in the right loin through
the lumbar triangle (of Petit), lateral to the right kidney, and the
displaced viscera may then be returned to thejr original positions.

When a stone is impacted in the ampulla of Vater, a more
direct approach is obtained by the trans-duodenal route. A
vertical incision is made in the supra-colic portion of the second
part of the duodenum, and the stone can then be felt under the
mucous coat of the postero-medial wall. The orifice of the
duodenal papilla lies under cover of one of the plicae circulares
(valvulse conniventes), and may sometimes be located by
expressing some bile from it.

The exit from the ampulla of Vater is then enlarged by
slitting it in an upward direction until it permits of the extraction
of the stone.

The bile-duct may be exposed to considerable pressure from
the head of the pancreas in malignant disease or in chronic
pancreatitis, on account of the intimate relation of the two
structures. In the former, the steadily increasing obstruction
is accompanied by the gradual onset of jaundice, which slowly
but surely increases in intensity ; in chronic pancreatitis the
colour changes are more irregular. It sometimes happens that
a calculus ulcerates from the duct into the gland and constitutes
a foreign body in the head of the pancreas, which can only be
removed by incising the gland.

The Pancreas is an elongated gland, which crosses the
posterior abdominal wall from right to left with an upward
inclination. It consists of a head, a neck, a body and a tail,
and, with the exception of the tail, which usually lies between
the two layers of the lieno-renal ligament, it is entirely retro-
peritoneal.

The head lies in the concavity of the duodenum and is
covered anteriorly by the pylorus, above, and the transverse
colon, below. Posteriorly, it rests upon the inferior vena cava and
the right renal vessels, and is grooved by the bile-duct (p. 315).

The neck passes upwards and to the left to become continuous
with the body. It is covered anteriorly by the peritoneum on
the posterior wall of the omental bursa and supports the pyloric
end of the stomach. Behind it the superior mesenteric and
splenic veins unite to form the portal vein.

The body of the pancreas crosses the middle line at or a
little below the transpyloric plane. It is somewhat triangular
on section and consequently possesses three surfaces. The

3i8 THE ABDOMEN AND PELVIS

anterior surface is covered by the peritoneum on the posterior
wall of the omental bursa (Fig. 85) and forms part of the
stomach-bed. The inferior surface is covered by the peritoneum
of the greater sac and is in relation to both infra-colic compart-
ments and the duodeno-jejunal flexure. These two surfaces
are separated from one another by the anterior border of the
gland, along which the two layers of the transverse meso-colon
separate from one another (Fig. 85). The posterior surface
crosses in front of the aorta, the left suprarenal gland and the
left kidney (Fig. 87), and is partially separated from all of these
structures by the splenic vein.

The tail of the pancreas usually lies between the two layers
of the lieno-renal ligament and is related to the left colic flexure,
inferiorly.

The Pancreatic Duct commences in the tail and traverses
the whole gland near its posterior surface. It emerges from
the right border of the head and opens into the ampulla of Vater,
together with the bile duct. An accessory duct drains part of
the head and opens into the duodenum above the ampulla. It
may communicate with the main pancreatic duct, and when it
does so it may convey the whole of the pancreatic secretion to
the duodenum in the event of obstruction of the terminal part
of the main duct (p. 315). When the obstruction is not relieved
in this way, retention cysts may arise in the gland.

Cysts of the Pancreas may project (i) from its anterior sur-
face, (2) from its anterior border, or (3) from its inferior surface.

(1) Cysts on the anterior surface of the gland project into
the omental bursa. As they enlarge, they may push the lesser
omentum forwards and reach the anterior abdominal wall above
the lesser curvature ; or they may push forwards the upper
part of the greater omentum and reach the surface below the
greater curvature but above the transverse colon.

(2) Cysts which appear on the anterior border may separate
the two layers of the transverse meso-colon and thrust the
transverse colon before them to the surface. In this condition
the dull percussion note over the tumour is interrupted by the
tympanitic note of the transverse colon.

(3) Cysts which appear on the inferior surface of the gland
project into the infra-colic compartment and thrust the greater
omentum before them. They come into contact with the
anterior abdominal wall below the transverse colon.

The Arterial Supply of the Pancreas is derived from

THE ABDOMINAL CAVITY 319

three sources, (i) The superior pancreatico-duodenal, a branch
of the gastro-duodenal (p. 296), and (2) the inferior pancreatico-
duodenal, a branch of the superior mesenteric (p. 323), supply
the head of the gland. (3) The pancreatic branches of the
splenic artery supply the rest of the gland.

The Veins of the Pancreas join the splenic vein, but a fairly
large vein issues from the dorsal aspect of the head and runs
upwards, to the left of the bile-duct, to join the portal vein.
This vessel may give rise to haemorrhage during the exposure of
the third part of the bile-duct (p. 315).

Development of the Pancreas.— The pancreas is developed from two
hollow buds, of which one springs from the ventral and the other from the
dorsal aspect of the duodenum. The ventral bud arises at the same point
as the liver-bud, but it only forms a small portion of the head of the
pancreas, while the dorsal bud gives rise to the rest of the head, to the
neck, body and tail of the gland. The two masses of cells grow into the
mesentery of the duodenum and fuse with one another. Their ducts also
unite and, as growth proceeds, the proximal part of the dorsal duct remains
small, so that the main adult duct is derived from the ventral duct and
the distal part of the dorsal duct, and consequently opens into the ampulla
of Vater in common with the bile-duct. Although small, the proximal
part of the dorsal duct persists as the accessory pancreatic duct and
retains its original connection with the duodenum. The communication
of the two primitive ducts with one another may or may not be retained
(see p. 315).

The Spleen lies in the left hypochondriac region under
cover of the ninth, tenth, and eleventh ribs, and its long axis
corresponds roughly to the tenth. It is almost completely
surrounded by peritoneum and projects into the greater sac
between the stomach and the lateral part of the left kidney.
It is attached to the greater curvature of the stomach by the
gastro-splenic ligament, and to the anterior surface of the left
kidney by the lieno-renal ligament (Fig. 87). The postero-
lateral aspect of the spleen lies in contact with the diaphragm,
and its antero-medial surface is related to the stomach, in front,
the kidney, behind, and the left colic flexure and the phrenico-
colic ligament, below.

The diaphragmatic surface of the spleen is roughly
triangular in shape, and its apex or superior angle can be
indicated on the dorsal surface of the body at a point i| inches
lateral to the tenth thoracic spine. Its inferior angle lies
opposite the eleventh intercostal space about 3^ inches lateral
to the first lumbar spine, and its anterior angle is placed on the
mid-axillary line in the ninth intercostal space (Fig. 84). When
these points are joined to one another by lines which are slightly

320

THE ABDOMEN AND PELVIS

convex outwards, the surface outline of the diaphragmatic
surface of the spleen is obtained (Stiles). It will be seen from

FIG. 99. — Dissection to expose the Spleen. Portions of the 5th- nth ribs
have been resected. A part of the lower lobe of the left lung and a
part of the left half of the diaphragm have also been removed.

Fig. 99 that the whole of this surface is separated by the
diaphragm from the left pleural sac ; in addition, in its upper
part it is overlapped by the inferior margin of the left lung

THE ABDOMINAL CAVITY 321

(p. 292). In puncture of the normal spleen, the needle must
pass through the muscular wall, the pleural sac, the diaphragm
and the peritoneal cavity before the organ is reached.

The splenic artery has already been described (p. 296).

The splenic vein issues from the hilUm of the spleen and
is at once joined by the left gastro-epiploic veins and the venae
breves, which pass from the stomach between the two layers
of the gastro-splenic ligament. It then runs backwards in the
lieno-renal ligament to the posterior abdominal wall, where it
turns to the right behind the pancreas. It receives numerous
pancreatic veins, and is joined, near its termination, by the
inferior mesenteric vein. Behind the neck of the pancreas it
is joined by the superior mesenteric vein, and the two together
form the portal vein. Portal obstruction, therefore, invariably
gives rise to venous congestion of the spleen (p. 310).

The lymph vessels of the spleen terminate in the lymph
glands at the hilum. From these splenic glands the afferents
pass to the pancreatic and cceliac lymph glands.

Splenic Enlargement. — When the spleen becomes enlarged,
in malaria, splenic anaemia and other diseases, its anterior
border projects beyond the left costal margin and is in contact
with the deep surface of the anterior abdominal wall. Normally
this border possesses one or two notches or indentations, and in
splenic enlargement the notches become more pronounced. On
palpation of a tumour in the left lumbar region, the discovery of one
or more notches on its anterior border may settle the diagnosis.

The direction taken by the enlarging spleen is usually
obliquely downwards and medially, as the phrenico-colic ligament
and the splenic flexure obstruct its enlargement in a purely
downward direction.

Splenectomy. — Owing to its vascularity, stab wounds or rupture of the
spleen give rise to severe haemorrhage, and removal of the organ may be
necessary. Good access is obtained by an incision similar to that described
for operations on the gall-bladder (p. 25 2), but on the opposite side, or by a
long vertical incision through the left rectus. Thereafter, two methods
are open to the surgeon, (i) The omental bursa is opened by tearing
through the greater omentum just above the transverse colon. The stomach
is retracted upwards and the peritoneum is cautiously divided at the upper
border of the pancreas. The splenic artery is exposed and the vein is found
at a slightly lower level. Both vessels are tied in this situation, and the
haemorrhage is at once reduced. The gastro-splenic ligament may now be
ligatured and divided piece by piece. When the lieno-renal ligament has been
similarly treated, the spleen can be removed.

(2) The spleen is drawn forwards to the abdominal wound, and the left
side of the lieno-renal ligament is exposed. The ligament is ligatured and
divided piece by piece. The spleen is then drawn over to the left in order

21

322 THE ABDOMEN AND PELVIS

that the same procedure may be carried out with regard to the gastro-splenic
ligament.

It may not be possible to carry out the second method if perisplenitis has
caused adhesions to form between the spleen and the diaphragm.

Small Intestine. — The freely movable part of the small
intestine extends from the duodeno-jejunal flexure to the
caecum. The upper two-fifths constitutes the jejunum and
the lower three-fifths the ileum, but there is no definite line of
demarcation. These two parts of the alimentary canal together
measure about twenty-three feet, and they are suspended from
the posterior abdominal wall by the mesentery, which gives
them an almost complete investment of peritoneum. The coils
of the jejunum and ileum occupy the infra-colic compartments
and the pelvis, and are usually covered over by the greater
omentum. In most cases the first loop of the jejunum can be
found on the anterior surface of the left kidney, near its lower
pole, while the lowest loop of the ileum lies in the pelvis.

The Mesentery. — The root of the mesentery begins on the
anterior surface of the fourth part of the duodenum in front of
the left side of the second lumbar vertebra, and extends down-
wards and to the right. It crosses, successively, in front of
the third part of the duodenum, the aorta, the inferior vena
cava, the right ureter and the psoas major, and terminates in
the right iliac fossa at the ileo-caecal junction. This line of
attachment is only six or seven inches in length, and, in order
to enclose the twenty-three feet of intestine, the mesentery
spreads out in a fan-shaped manner and becomes very much
pleated near the gut. Its depth varies, being as much as seven
or eight inches at its deepest part. The two peritoneal layers of
which it consists contain between them nerves, blood-vessels,
lymph vessels (lacteals) and glands, and a varying amount of
fat. The latter is more thickly deposited along the root, and it
diminishes in quantity as the mesentery is traced to the intestine.
This feature is much better marked in the upper than in the
lower end of the mesentery, and, when it is examined near the
duodeno-jejunal flexure, semi-translucent peritoneal " windows "
can be seen, separated from one another by branches of
the superior mesenteric artery (Fig. 100). These " windows "
become more obscure as the jejunum is traced downwards, and,
in the lower part of the ileum, they cannot be distinguished
owing to the larger deposition of fat near the gut (Fig. 101).
By the examination of the mesentery, therefore, it may be

THE ABDOMINAL CAVITY

323

possible to determine whether a loop of small intestine, drawn
out through an abdominal wound, belongs to the upper or lower
part of the canal. At the same time it is important that the
surgeon should be able to distinguish the proximal from the
distal end of such a loop. If its mesentery is not twisted in
any way — this can be ascertained by tracing it back to the

FIG. ioo. — A Coil from the upper part of the Jejunum. The peritoneum
has been partially removed to show the arterial arcades. Compare the
appearance of the "windows" and the disposition of the fat in the
mesentery with Fig. 101.

vertebral column — the upper or left end of the loop on the surface
is also in reality its proximal end.

The Superior Mesenteric Artery arises from the aorta
behind the pancreas and descends in front of the third part of
the duodenum. It then enters the root of the mesentery and
runs downwards and to the right at a distance of about half an
inch from the posterior abdominal wall.

Close to its origin it gives off the inferior pancreatico-duodenal
artery, which runs to the right between the head of the pancreas

21 a

324

THE ABDOMEN AND PELVIS

and the duodenum, supplying both these structures and anastom-
osing with the superior pancreatico-duodenal (p. 296).

The intestinal arteries form a series of twelve to fifteen
branches, which arise from the left side of the superior mesenteric
and pass towards the jejunum and ileum. They break up into
branches which unite and reunite to form a connected series of
arcades, which are more complex in the ileum than in the
jejunum (Fig. 101). From the terminal arcades, small branches
pass to the mesenteric border of the gut and there bifurcate.

FIG. 101. — A Coil from the lower part of the Ileum. The peritoneum has
been partially removed to show the arterial arcades. Observe how the
fat in the mesentery overlaps the gut, and compare with Fig. 100.

In the intestinal wall they run parallel to the circular muscular
coat, at first in the subserous, then in the muscular, and finally
in the submucous coat.

The ileo-colic (p. 333), right colic (p. 336) and middle colic
arteries (p. 336) are described in connection with the large
intestine.

In dividing the bowel, previous to carrying out an
anastomosis, it is advisable to remove less of the mesenteric
than of the anti-mesenteric border in order that the retained
cut margin may have a good blood-supply.

The lymph vessels of the jejunum and ileum join the

THE ABDOMINAL CAVITY 325

superior mesenteric lymph glands, which lie between the two
layers of the mesentery. This group includes a large number
(100 to 200) of glands, and may be directly infected with
tuberculosis from the alimentary canal, When they break
down they involve one or both of the infra-colic compartments.
Their efferent s join the pre-aortic glands.

In the walls of the small intestine the lymph vessels run at
right angles to the long axis, and when they are infected from
the tuberculous ulceration of an aggregated lymph nodule (Peyer's
patch), the spread of the disease along them may produce a
stricture of the gut. These lymph nodules are most numerous
in the terminal part of the ileum, and it is consequently the
commonest site for tuberculous stricture. On this account, too,
enlarged glands are frequently found in the region of the colic
(iieo-caecal) valve.

The nerves of the small intestine are derived from the
aortic sympathetic plexus, and their centres in the spinal
medulla lie in the ninth, tenth, and eleventh thoracic segments.
Referred pain in connection with this part of the alimentary
canal is felt in the areas supplied by the ninth, tenth, and
eleventh thoracic nerves (Fig. 72), and, clinically, it usually
involves the umbilical region, only occasionally spreading to
the lumbar region and the back. When an inguinal hernia
which contains small intestine becomes strangulated, the pain
is at first experienced near the umbilicus and not immediately
over the swelling.

Structure of the Small Intestine. — Under the serous (peritoneal)
coat, the small intestine possesses a very strong muscular coat. This consists
of an outer longitudinal and an inner circular layer, both of which are com-
plete and uninterrupted from the pylorus to the colic (ileo-caecal) valve.
The mucous coat is thick, and it is thrown into ridges, the plicce circulares
(valvulce conniventes), which begin at the second part of the duodenum, and
are most numerous in its third and fourth parts and in the upper part of the
jejunum. Lower down they decrease in number, and they are entirely
absent in the lower part of the ileum. In this situation the aggregated lymph
nodules (Peyer's patches), which are not present in the jejunum, are fairly
numerous and may measure 4 x \ inches. They form somewhat granular
patches in the mucous coat, and lie along the anti-mesenteric border of the
gut.

Intestinal Stasis. — Near its termination, the ileum may
become kinked and obstructed by a fibrous band, which varies
in width from a half to two inches. It may pass downwards
and to the right on the deep surface of the mesentery, or it may
ascend from the pelvis as a thickening of the posterior parietal

21 b

326 THE ABDOMEN AND PELVIS

peritoneum. In the former case,, the apex of the kink is directed
upwards, and the proximal and distal limbs of the ileum,
respectively, ascend and descend ; in the latter case, the condition
is exactly reversed.

It is generally stated that these bands result from attacks
of appendicitis, but Lane urges that those which hold the ileum

FIG. 102.— Partial Prolapse of the Caecum. The Bismuth is also visible in
the Vermiform Process, which passes towards the left and then turns
downwards into the pelvis. The vermiform process in this radiogram
resembles the appearance of a "Lane's Kink," but, at the subsequent
operation, it was found in the position shown in the figure and with the
bismuth still in situ.

up in the abdomen are produced naturally to give support to a
prolapsing caecum. The kinks may be observed in radiograms
taken from ten to twelve hours after a bismuth meal. The
constricted portion of the terminal part of the ileum is recognised
by the narrow shadow of the contained bismuth, while the
stronger wide shadows represent the proximal limb of the kink
and the caecum, which can be identified by its characteristic

THE ABDOMINAL CAVITY 327

shape. It should be remembered that the shadow produced
by a distended vermiform process, which is constricted near
its base, may be misinterpreted as an ileal kink (Fig. 102).

The condition may be relieved by dividing the fibrous band
transversely, but Lane contends that recurrence is certain and
that ileo-pelvic-colostomy is necessary (p. 345), together with
the removal of the intervening part of the large intestine. Good
results follow resection of the caecum and the terminal part of
the ileum, with an end-to-side anastomosis between the ileum
and the ascending colon.

Meckel's Divertieulum. — In the early human embryo the
mid-gut communicates freely with the yolk-sac through the
vitello-intestinal duct, which leaves the abdominal cavity at the
site of the umbilicus (Fig. 89). As the embryo develops, the
duct becomes occluded and later entirely disappears, but total
or partial persistence of its mtra-embryonic portion occurs in
about two per cent of subjects. It is then known as a Meckel's
diverticulum, and the condition constitutes the commonest
congenital anomaly of the small intestine. Many varieties are
met with, from a complete intestinal diverticulum opening at
the umbilicus to a small elevation on the wall of the gut, but
the diverticulum always springs from the anti-mesenteric border
of the intestine and usually within three or four feet of the lower
end of the ileum.

In complete persistence — congenital umbilical fistula — the
duct may be several inches in length, or it may be so short that
the ileum itself appears to open on the surface (Fig. 103, i).
In the latter case the dorsal or mesenteric wall of the gut may
prolapse through the opening, giving rise to a turgid swelling
at the umbilicus and possibly causing intestinal obstruction.
This condition presents an appearance very similar to that
produced by the persistence of a small portion of the extra-
embryonic part of the vitello-intestinal duct, which discharges
mucus and is not necessarily associated with a Meckel's
diverticulum (Fig. 103, iv). The passage of a probe at once
serves to indicate which of the two varieties is present.

In partial persistence the duct is represented by a blind
diverticulum which may sometimes be attached to the umbilicus
by a fibrous cord (Fig. 103, v). The free diverticulum is the
commonest variety ; it is subject to inflammatory attacks
and may form adhesions to any structure in its neighbourhood,
often giving rise to intestinal obstruction. As the centres for

328

THE ABDOMEN AND PELVIS

the diverticulum and the vermiform process (appendix) occupy
the same segment in the spinal medulla, the reflex sensory
symptoms are very similar, and consequently inflammation of
the diverticulum may easily be mistaken for appendicitis. In
the cystic variety (Fig. 103, v) only the middle part of the
intra-embryonic portion of the duct remains patent.

Differences between the Large and Small Intestine.—
The large intestine differs from the small intestine in its outward
appearance in several particulars, (i) The longitudinal muscular
coat does not surround the large intestine completely. Instead,
it forms three narrow bands, termed the tcenicz coli, which are
visible through the serous coat. (2) The large intestine is
sacculated. (3) Appendices epiploicce are found on the large

I II III IV V

FIG. 103. — Diagrams to illustrate different degrees of Persistence of

the Vitello-intestinal Duct.

I, II and III show different stages in the production of a hernia of the dorsal wall of
the small intestine through a patent vitello-intestinal duct and umbilicus.

IV shows a patch of granulations at the umbilicus and a partially obliterated vitello-
intestinal duct.

V shows incomplete obliteration of the vitello-intestinal duct with the formation of a
small cyst near the umbilicus.

The heavy black lines represent the small intestine, and the shaded area represents
the anterior abdominal wall. The dotted line represents the peritoneum.

intestine ; they consist of small peritoneal sacs filled with fat.
(4) The wall of the large intestine is thinner than the wall of the
small intestine. This difference is referable to the longitudinal
muscular and the mucous coats.

These features of the large intestine are subject to a good
deal of variation.

The Colic (Ileo-Caecal) Valve is placed at the junction of
the ileum with the large intestine, and it serves to demarcate
the caecum, which lies below it, from the ascending colon, which
lies above it. The position of the valve may be indicated on
the surface at the point of intersection of the intertubercular
and the right lateral planes.

THE ABDOMINAL CAVITY 329

The valve consists of an upper and a lower segment, which
bound a horizontal slit, directed forwards and to the right.
The segments are produced by an invagination of the mucous,
submucous, and circular muscular coats of the ileum and
caecum, but the longitudinal fibres and the serous coat take no
part in their formation. Villi are found on the ileal surface of
the valve, but the mucous membrane of its caecal surface possesses
the characteristic features of large intestine. Two ridges, which
are known as \hefrcenula, pass one from each end of the slit and
run half-way round the gut.

The colic valve is arranged so as to prevent the regurgitation
of chyme into the ileum, while, at the same time, it offers no
hindrance to the passage from the ileum into the caecum. When
the caecum is loaded the fraenula become tightly stretched, and,
as a result, the valve is securely closed.

The Caecum is a blind sac about 2\ inches long and 3 inches
wide. Normally it occupies the right iliac fossa, and is
completely invested by the peritoneum, so that it can be lifted
upwards and forwards out of the abdomen. It may sometimes
possess a mesentery, or it may not be covered by peritoneum
posteriorly, in which case it cannot be withdrawn from the
abdomen until it has been mobilised (Fig. 104, i). Owing to the
laxity of the peritoneum, the normal range of movement may be
considerably increased in some cases (mobile ccecum), and this
may predispose to conditions of pericolitis, with symptoms
closely resembling appendicitis.

A freely movable caecum may prolapse into the pelvis and
become distended with gas and fluid, which are hindered from
escaping by the pressure of the pelvic brim and the superimposed
coils of small intestine. As it enlarges, the over-distended
caecum drags down the parietal peritoneum, giving rise to painful
symptoms. When the gut collapses, on the escape of its
contents, the loose peritoneum over it fails to return to its
former position owing to lack of elasticity and becomes wrinkled
and thrown into vascular folds, which are known as " Jackson's
veil." This condition is frequently seen in the region of the
caecum and ascending colon during operations for recurrent
appendicitis. Its origin has been variously described as
congenital, as a result of gradual ptosis of the caecum, and as
inflammatory following chronic pericolitis. " Jackson's veil "
is very commonly seen in children and is often met with in the
adult, but it is rarely to be observed in the cadaver.

330 THE ABDOMEN AND PELVIS

Inferiorly, the caecum is supported by the lowest part of the
abdominal wall, and, when distended, it may form a palpable,
and sometimes visible, tumour in this region, while gurgling
can often be produced by manipulations. Owing to its proximity
to the right abdominal inguinal (internal abdominal) ring, the
caecum and vermiform process are occasionally found in a right
inguinal hernia in children.

In structure the caecum resembles the rest of the large intestine.
The longitudinal muscular coat forms three distinct bands or
taeniae. Of these one is found on the anterior surface of the
bowel, a second on the posterior surface, while the third is placed
on the medial surface. These three bands converge on the
base of the vermiform process, which they provide with a
complete longitudinal coat. The circular muscular coat, as in
the small intestine, is uninterrupted, and the mucous coat
contains a large amount of lymphoid tissue.

Three peritoneal fossae or recesses occur near the termination
of the ileum. (i) The superior ileo-ccecal recess (ileo-colic) lies in
the angle between the ileum and the ascending colon. The an-
terior caecal artery raises a fold of peritoneum from the posterior
abdominal wall, and it forms the anterior boundary of the recess.
The mouth of the fossa looks downwards and to the left.

(2) The inferior ileo-ccecal (ileo-appendicular) recess lies in
the angle between the ileum and the caecum. Its anterior wall
is formed by the ileo-caecal fold (bloodless fold of Treves), and
its posterior wall is usually formed by the mesentery of the
vermiform process. The ileo-caecal fold is triangular in shape ;
its apex is situated at the ileo-caecal junction and its base is free,
forming the anterior boundary of the mouth of the fossa.

(3) The cacal (retro-c(ecal) fossa is the largest and most con-
stant of the fossae in this region. It extends upwards behind the
caecum as far as the line of peritoneal reflection from that viscus
to the floor of the iliac fossa. It is sometimes limited laterally
by a fold which passes downwards and laterally across the lower
part of the right para-colic gutter from the caeco-colic junction.

The Vermiform Process (Appendix) springs from the
postero-medial aspect of the caecum about one inch below
the ileo-colic junction, and can always be found by tracing
the anterior taenia coli downwards. It is usually about 3! inches
long and £ inch wide, but its length is very variable, being
relatively greater in the child than it is in the adult. The
orifice of the vermiform process communicates with the caecum

THE ABDOMINAL CAVITY 331

and is guarded by a crescentic fold of mucous membrane.
Absence or incompetence of this valve may account for the
presence of faecal matter within the process.

The mesentery of the vermiform process is a triangular fold,
which is derived from the left or lower layer of the mesentery of the
ileum. It is sometimes shortened and attached to the posterior
abdominal wall near the pelvic brim. Occasionally the vermiform
process has no mesentery and is entirely retro-peritoneal.

Although its base is constant in position, in relation to the
caecum, the process itself possesses a wide range of movement
and may occupy any one of the following situations :

(1) It may pass upwards and to the left, under cover of the
mesentery ; this is known as the splenic position. When the
process is retro-peritoneal in this situation, it may lie behind
or within the root of the enteric mesentery.

(2) The vermiform process may pass downwards and to the
left, occupying the pelvic position. Inflammatory attacks may
give rise to adhesions which connect it to the rectum, bladder,
etc. In these cases defsecation or micturition may cause painful
symptoms by traction on the adherent vermiform process, and
an appendicular abscess may discharge by the rectum or the
urethra. When the vermiform process occupies the pelvic
position in the female, it is brought into close relationship with
the right ovary ; and if signs of inflammation occur, it may be
a matter of great difficulty to decide whether the vermiform
process or the right ovary is at fault. The relation of the pain
to the menstrual period may aid in the diagnosis. Valuable
information may be obtained by means of a rectal or a vaginal
examination. When the process is retro-peritoneal in the pelvic
position, it lies immediately in front of the common iliac vessels
and the ureter, and difficulty may be experienced in mobilising
it in appendicectomy.

(3) The vermiform process may pass forwards towards the
anterior abdominal wall — the anterior position — but it can only
do so when it possesses a mesentery. If it becomes inflamed
in this situation the greater omentum usually surrounds it,
and the mass so formed can often be recognised on abdominal
palpation. Should an abscess form and rupture, the right infra-
colic compartment may be infected (p. 285).

(4) The vermiform process very frequently takes up a
position behind the caecum and then has a varying relation to
the peritoneum, (a) It may possess a mesentery and lie free

332

THE ABDOMEN AND PELVIS

in the caecal (retro-csecal) fossa, (b) It may be plastered on to
the posterior aspect of the caecum by the peritoneum, and it

FIG. 104. — Diagrams to illustrate the varying relationships of the Caecum,
the Vermiform Process and the Ascending Colon to the Peritoneum.

1. Absence of caecal fossa ; posterior wall of caecum not covered by peritoneum.

2. Normal condition. Caecal fossa present.

3. Csecal fossa extending upwards behind ascending colon. Vermiform process retro-
caecal in position but surrounded by peritoneum.

4. Vermiform process retro-caecal in position but enclosed by the peritoneum surround-
ing the caecum.

5. As i but vermiform process is entirely extra-peritoneal.

6. Prolapse of caecum.

7. " Undescended caecum." The terminal part of the ileum, as it ascends to the
caecum, is retro-peritoneal. The vermiform process is extra-peritoneal except at its tip,
which is lying in front of the kidney in the posterior wall of the hepato-renal recess.
The ascending colon and the right colic flexure form a "double-barrelled " colon.

8. Ascending colon with persisting mesentery, such as is met with in intussusception.
Note. — The dotted line represents the position of the lumbo-sacral articulation.

then lies in the anterior wall of the fossa, (c) In cases where
the caecum is not covered by peritoneum posteriorly,, the retro-

THE ABDOMINAL CAVITY 333

csecal vermiform process lies in contact with the fascia iliaca
and is only in contact with peritoneum at its base (Fig. 104, 5.)

The course taken by an abscess in connection with a retro-
caecal vermiform process will depend on which of the three
varieties is present. In (a) the abscess forms in the lowest part
of the right para-colic gutter and reaches the anterior abdominal
wall close to the anterior superior iliac spine. It then gives
rise to a swelling, which is dull on percussion. Adhesions,
however,, may shut off the caeca! fossa so that the abscess, as
it enlarges, pushes the caecum forwards with the result that a
tympanitic note is obtained on percussion over the swelling.

In (b) the abscess may rupture through the gut wall or it may
burst into the caecal fossa, in which event the condition is the
same as that described for (a).

In (c) the abscess forms in the extra-peritoneal fat. The
caecum is thrust forwards against the anterior abdominal wall
so that a tympanitic note is obtained on percussion, and this
may be misleading, unless the possibility of an extra-peritoneal
abscess is kept in mind. Delay in recognising this condition
allows the pus to spread upwards behind the peritoneum until
it reaches the extra-peritoneal subphrenic danger zone.

Such an abscess may be evacuated by the extra-peritoneal
route, but the access is rarely sufficient for removal of the
vermiform process, and, further, a wide extent of cellular tissue
is necessarily opened up. It is, therefore, better to empty it
through the peritoneal cavity. The area medial to the ascending
colon and caecum is packed off, and the floor of the right para-colic
gutter is incised. In this way the caecum is rendered movable
and can be retracted medially. The abscess can be evacuated
and the vermiform process removed through the extended
grid-iron incision (p. 248).

(5) The infra-hepatic position is referred to on p. 346.

The ileo-colic artery arises from the superior mesenteric
below the third part of the duodenum, and runs downwards
and to the right in front of the right ureter and psoas major
(Fig. 1 06). It breaks up near the ileo-colic fossa into branches
which supply (i) the terminal part of the ileum, (2) the ascending
colon, (3) the caecum, and (4) the vermiform process. The
caecal arteries, anterior and posterior, supply the anterior and
posterior surfaces of the caecum. The artery to the vermiform
process descends behind the ileum and enters the free border
of the mesentery of the vermiform process. It does not

334 THE ABDOMEN AND PELVIS

anastomose with any other artery, and therefore, when it
becomes kinked or obstructed,, the blood-supply of the process
is entirely cut off and gangrene ensues.

Intussusception. — A condition of incipient intussusception
is always present on account of the invagination of the circular
muscular coat into the segments of the colic (ileo-csecal) valve.
This constitutes a predisposition to ileo-ccecal intussusception ,but
the condition can only occur when the ascending colon possesses
a mesentery. The frequency of its incidence during the first year
is explained by the fact that the relative disproportion in calibre
between the large and small intestine is greatest at that period.

It is said that if a wave of peristalsis passes up the caecum
just as one ends on the ileum, the colic valve, which is at that
moment projected furthest within the lumen of the caecum, is
seized by the contracting caecum and squeezed upwards along
the ascending colon. When the angle at which the ileum joins
the colon is greater than 90°, intussusception occurs more readily.

In this variety the colic valve forms the apex of the
intussusceptum, and as it passes along the large intestine, the
caecum, vermiform process and ascending colon are dragged in
together with the ileum and its mesentery. Finally, the colic
valve may appear at the anus.

In the ileo-colic variety the intussusception begins in the
ileum, usually near its terminal portion. The part of the gut
which constitutes the starting-point of the condition remains
at the apex of the intussusceptum (Fitzwilliams), both before
and after it has passed through the colic valve. If the ascending
colon possesses a mesentery, the subsequent course of events is
the same as in the ileo-caecal variety. If the ascending colon
has no mesentery, the intussusception stops at the valve.

The Ascending Colon runs upwards on the iliacus, the
quadratus lumborum, and the lower pole of the right kidney
(Fig. 88) ; it is separated from both muscles by their fascia
and from the kidney by the peri-nephric fascia. It separates
the right para-colic gutter from the right infra-colic compartment,
and is bound to the posterior abdominal wall by the peritoneum,
which clothes its anterior, medial, and lateral surfaces.
Occasionally the right margin of the greater omentum is fused
with the peritoneal covering of the ascending colon. In that
case the right half of the transverse colon is often closely related
to the ascending colon, forming what has been termed the
" double-barrelled gun " arrangement (Fig. 105).

THE ABDOMINAL CAVITY

335

The Right Colic (Hepatic) Flexure lies under cover of the
ninth and tenth costal cartilages in the interval between the
inferior surface of the right lobe of the liver and the anterior
surface of the lower pole of the right kidney. It is formed by
the terminal part of the ascending colon, which turns downwards,
forwards, and to the left to become continuous with the transverse
colon. Its medial surface is in contact with the gall-bladder,
anteriorly, and with the second part of the duodenum, posteriorly.

FIG. 105. — "Double-barrelled" Colon. The dark mass on the left of the
figure consists of the caecum, the ascending colon and the first part of
the transverse colon.

When the body is in the supine position, the flexure lies a
little below the trans-pyloric plane, but radiograms show that,
in the erect posture, it descends, sometimes even to the level
of the iliac crest (fourth lumbar vertebra). The amount of
peritoneum which persists in this region is very variable, and
this fact may account for the wide range of movement.

The Transverse Colon extends from the right to the
left colic flexure. As it crosses the abdominal cavity it takes
a downward curve, usually reaching its lowest point in the

336 THE ABDOMEN AND PELVIS

middle line where, in the supine position, it lies at or a little
below the umbilicus. In many cases, however, the transverse
colon is placed at a much lower level, and its position depends
on (i) its length, which may be greatly increased, e.g. in cases
of undescended caecum (p. 346), and (2) the length of the
transverse meso-colon.

In the erect posture the transverse colon descends still
further, and is often seen lying behind the pubic symphysis.
Under these circumstances, the right and left colic flexures
become very acute, and the proximal part of the transverse
colon descends in front of or medial to the ascending colon.
If these two pieces of bowel are attached to one another
by peritoneal bands (p. 334) or adhesions, the kinking will
persist in the supine position and may give rise to delayed
peristalsis and chronic constipation.

The transverse colon is completely surrounded by peritoneum
except along narrow strips on its upper and lower surfaces,
where the transverse meso-colon and the greater omentum reach
the gut (Fig. 85).

The transverse meso-colon suspends the transverse colon
from the posterior abdominal wall. It is attached normally
to the front of the head, neck, and body of the pancreas, but it
may extend further over to the right and cross the anterior
surface of the second part of the duodenum. It separates the
cavity of the omental bursa from the infra-colic compartments
(Fig. 85), and is related to the stomach, anteriorly, and to the
duodeno-jejunal flexure and coils of small intestine, posteriorly.
The two layers of the transverse meso-colon contain the middle
colic vessels, lymphatics, and nerves.

The BLOOD-SUPPLY to the ascending colon, right colic flexure,
and the transverse colon is derived from (i) the right and (2)
the middle colic branches of the superior mesenteric artery.

(1) The right colic artery, which often arises by a common
trunk with the ileo-colic, runs to the right, behind the peritoneum
of the right infra-colic compartment. It crosses in front of the
right psoas major, ureter, and spermatic vessels, and usually
lies a little below the right kidney. Near the gut it divides
into a descending branch, which anastomoses with the colic
branch of the ileo-colic, and an ascending branch, which
anastomoses with the right division of the middle colic. Both
branches supply the ascending colon (Fig. 106).

(2) The middle colic arises from the superior mesenteric at

THE ABDOMINAL CAVITY

337

the lower border of the pancreas and enters the root of the
transverse meso-colon. Between its two layers the artery
passes downwards and to the right to supply the transverse

Para-colic glands

Middle colic
artery

Right colic
artery
Epi-colic glands

Intermediate

glands

Para-colic glands

Ileo-colic artery 5

Anterior caecal
artery

Superior
haemorrhoida

Caecu
Vermiform process

Appendicular artery

Slender connection between lowest sigmoid
and superior haemorrhoidal artery

FIG. 1 06. — The Arteries and Lymph Glands of the Large Intestine.

colon. It divides into a right branch, which supplies the right
third of the transverse colon and anastomoses with the ascending
branch of the right colic near the right colic flexure ; and a left
branch, which supplies the left two-thirds of the transverse
colon and anastomoses with the ascending branch of the left

22

338 THE ABDOMEN AND PELVIS

colic near the left flexure of the colon. As the artery lies
somewhat to the right of the middle line, openings in the
transverse meso-colon are made on the left side (p. 301).

- The lymph vessels of that portion of the large intestine
which is supplied by the superior mesenteric artery mainly
follow the course of the chief blood-vessels. The lymph glands
are divided by Jamieson and Dobson into four groups, (i)
The epi-colic lymph glands are situated on the wall of the gut.
(2) The para-colic lymph glands lie on the medial side of the
ascending colon behind the posterior parietal peritoneum ; and
above the transverse colon, between the two layers of its
mesentery. (3) The intermediate lymph glands are associated
with the ileo-colic, right, and middle colic vessels. (4) The
central group lies along the superior mesenteric vessels (Fig. 106).

Efferents pass from the epi-colic to the para-colic lymph
glands, from the para-colic to the intermediate group, and from
the intermediate to the central group. Some efferents from
the bowel and epi-colic lymph glands pass directly to the
intermediate group, and, on this account, the latter must be
removed together with the bowel and the para-colic lymph
glands in malignant disease (p. 339). In removing retro-
peritoneal lymph glands, the peritoneum which covers them
must also be taken away. This leaves a part of the posterior
abdominal wall bare, and the surrounding peritoneum requires
to be undermined before it can be drawn together over the
denuded area.

Removal of Caecum and Ascending Colon. — The parts
dealt with in this operation are more or less fixed in position,
and their blood and lymph vessels lie behind the posterior
parietal peritoneum. For these reasons the resection of the
ascending colon presents more difficulty than the removal of
a part of the small intestine, where the gut is freely movable
and its blood and lymph vessels are easily controlled as they
lie in the mesentery.

The extent of malignant or tuberculous disease in the ileo-
csecal region may be so limited that only a comparatively small
piece of the gut requires to be removed. If, however, the right
colic (hepatic) flexure is not freely movable, some difficulty may
be experienced in approximating the two cut ends in the subse-
quent anastomosis. Under these circumstances it is advantageous
to remove the flexure in addition to the diseased area, and the
more movable transverse colon can then be united to the ileum.

THE ABDOMINAL CAVITY 339

After the abdomen has been opened (p. 250), the surgeon
(i) may first ligature the ileo-colic and right colic arteries and
then proceed to free the bowel ; or (2) he may free the bowel
first and secure the vessels at a later stage. In the first method
the vessels are found behind the peritoneum on the posterior
wall of the right infra-colic compartment (Fig. 107).

In the second method a vertical incision is made through
the peritoneum of the floor of the right para-colic gutter in its
whole extent, and it is then continued to the left behind the
caecum and below the ileum. The csecum and ascending colon
are then freed by dissecting with the fingers, and the peritoneum
is stripped off the posterior wall of the right infra-colic com-
partment. During these stages of the operation care must
be taken not to injure the right spermatic vessels, ureter, or the
second part of the duodenum (Fig. 107). The contents of the
right iliac fossa can now be drawn out of the abdomen and
turned over towards the left. While this is being done, the
right colic and ileo-colic vessels are secured on the deep surface
of the peritoneum. The ileum and ascending (or transverse)
colon are then clamped and divided, and the intervening portion
of bowel is removed, together with the adjoining area of
peritoneum up to the point where the arteries have been
ligatured. As the ileo-colic artery has been tied, the terminal
six inches of the ileum is dependent for its blood-supply on
the anastomosis between the ileo-colic and the termination of
the superior mesenteric. It is thus rendered unsuitable for
intestinal anastomosis and must be resected in order that the
piece of the ileum which is utilised for this purpose may possess
a free and ample blood-supply.

The Left Colic (Splenic) Flexure is deeply situated
under cover of the costal margin and is partially overlapped
by the stomach. On this account its examination is by no
means easy, and, therefore, tumours of the flexure are not
readily recognised at an early stage. Radiograms demonstrate
that its position is very constant. It lies under cover of the
eighth rib and its costal cartilage, to the left side of the left
lateral line, and it is held in place by its peritoneal connections.
Its upper aspect receives the attachment of the upper end of
the left border of the greater omentum ; its posterior surface
is attached to the pancreas by the left extremity of the transverse
mesocolon ; and, from its lateral aspect, the peritoneum passes
to the diaphragm forming a fold, which is called the phrenico-

22 a

340 THE ABDOMEN AND PELVIS

colic ligament. Superiorly, the flexure is in contact with the
lower end of the spleen, and, posteriorly, it rests on the lateral
part of the anterior surface of the left kidney.

The left colic artery, which is a branch of the inferior
mesenteric, runs upwards and to the left, behind the peritoneum
of the left infra-colic compartment and in front of the internal
spermatic vessels, ureter, and kidney. Before it reaches the
left colic flexure, the artery divides into a descending branch,
which runs downwards along the medial border of the descending
colon, and an ascending branch, which supplies the flexure and
then enters the transverse meso-colon to supply the transverse
colon and anastomose with the left branch of the middle colic.

The lymph vessels of the left flexure pass through the epi- and
para-colic lymph glands to reach the intermediate group on
the left colic artery. Jamieson and Dobson state that a few
lymph vessels from the flexure enter the splenic lymph glands,
and that, on this account, complete removal of the lymphatic
area in malignant disease of the flexure is impossible.

Resection of the left colic flexure involves the removal
of the left third of the transverse colon and the upper part of
the descending colon. This necessitates the division of (i) the
peritoneum in the left para-colic gutter, (2) the phrenico-colic
ligament, (3) the left part of the greater omentum, and (4) the
left part of the transverse meso-colon. In this way the flexure
is mobilised, and it can then be stripped downwards and medially
by the fingers. During this process care must be exercised
not to injure the kidney or ureter (cf. resection of right flexure,
p. 339). The ascending branch of the left colic artery is ligated
on the posterior surface of the peritoneum, and the left branch
of the middle colic is caught before the transverse colon and
meso-colon are divided.

The Descending Colon is about four inches long and
extends from the left flexure down to the iliac crest. Above,
it lies in the angle between the left kidney and the transversus
abdominis ; below, it lies on the quadra tus lumborum. It
separates the left infra-colic compartment from the left para-colic
gutter, and, anteriorly, it is in relation to the terminal part of
the transverse colon above, and to coils of small intestine below.
The peritoneum covers the descending colon in front and on
each side, but this part of the gut rarely possesses a mesentery.
The descending colon is in direct contact with the extra-peritoneal
fat (p. 275).

THE ABDOMINAL CAVITY 341

The Iliac Colon descends on the iliacus muscle to the
level of the antero-superior iliac spine and then turns medially,
parallel to, and a little above,, the inguinal ligament. It forms
the medial boundary of the left paracolic gutter and ends, at
the brim of the pelvis, by becoming continuous with the pelvic
colon. Like the descending colon, the iliac colon is retro-
peritoneal and rarely possesses a mesentery. Tumours of the
iliac colon are not difficult to recognise, as they may be palpated
by rolling the gut against the ilium. Scybalous masses may be
distinguished by the fact that they can be pitted on firm pressure.

The Pelvic Colon, which varies from ten to thirty inches
in length, is continuous with the iliac colon above and terminates
in front of the third piece of the sacrum, where it becomes
continuous with the rectum. It is suspended from the posterior
wall of the pelvis by a mesentery, termed the pelvic meso-colon,
and consequently is freely movable. The line of attachment
of its mesentery resembles an inverted V. It begins on the
medial border of the psoas major and passes upwards and
medially along the medial side of the external iliac vessels.
After crossing the hypogastric (internal iliac) artery, it bends
sharply downwards and ends in front of the third sacral vertebra.
On account of the arrangement of the mesentery, the terms
ascending and descending limbs are used with reference to the
pelvic meso-colon and to the parts of the gut which they enclose.

A small intra- peritoneal fossa, termed the inter sigmoid
recess, lies at the apex of the inverted V and is bounded on each
side by the left or lower layer of the pelvic meso-colon. This
recess is sometimes the site of an intra-peritoneal strangulated
hernia.

The pelvic colon is usually situated partly in the pelvis and
partly in the abdomen. When it possesses a long mesentery, it
may pass across the median plane, and it is not infrequently
seen during the operation of appendicectomy. In the child it
lies mainly in the abdomen, owing to the relatively small size
of the pelvic cavity.

The advantage taken by the surgeon of a freely movable
pelvic colon is pointed out on p. 343.

The Inferior Mesenteric Artery arises from the abdominal
aorta ij inches above its bifurcation. It runs downwards
and slightly to the left, and gives off the left colic (p. 340)
and the sigmoid arteries. Its downward continuation into the
pelvis is called the superior hcemorrhoidal artery.

22 b

342

THE ABDOMEN AND PELVIS

The sigmoid arteries, three or four in number, supply the
iliac and pelvic cola. They anastomose freely with one another,

Superior
mesenteric
artery
Right para-
colic gutter
Right and
middle colic

Lower
of left
kidney

FIG. 107. — The Posterior Wall of the Infra-colic Compartment. The greater
omentum and the transverse colon have been thrown upwards. The
mesentery has been divided close to its root and removed together with
the coils of the jejunum and ileum. A small part of the pelvic colon
and its mesentery has been resected to expose the pelvic portion of the
left ureter.

forming arterial arcades across the iliac fossa and in the pelvic
meso-colon. The highest of the series similarly anastomoses
with the descending branch of the left colic. The anastomosis
between the lowest sigmoid and the superior haemorrhoidal is

THE ABDOMINAL CAVITY 343

not always sufficient to re-establish the circulation, if the inferior
mesenteric artery is ligatured beyond the origin of the lowest
sigmoid branch. In abdomino-perineal or abdomino- sacral
removal of the rectum, the inferior mesenteric requires to be
ligated. If the ligature is applied below the origin of the lowest
sigmoid artery, the vitality of the lower part of the pelvic colon
is seriously imperilled. It is necessary, therefore, to apply the
ligature on the proximal side of the lowest sigmoid branch.
The anastomosis between the sigmoids is sufficient to ensure
the passage of blood through the lowest sigmoid back into the
inferior mesenteric, and thus the blood-stream reaches the pelvic
colon along the normal channel.

Colotomy. — The pelvic colon is usually selected as the site
for an inguinal colotomy on account of its wide range of
movement. A loop of the gut with its mesentery is brought
out of the abdomen through the left rectus and its sheath, or
through a gridiron incision which is made at a slightly lower
level than the appendicular incision (p. 248) on the opposite
side. A glass rod or rubber tube is passed through the mesentery
to support the bowel by resting on the skin surface on each side
of the wound, and the serous and muscular coats of the colon
are stitched to the parietal peritoneum.

Owing to the circular course followed by the blood-vessels
in the wall of the gut, the colotomy opening is made transversely.
If complete division of the bowel and its mesentery is carried
out, only one or two small vessels in the edge of the pelvic
meso-colon require to be tied. This part of the operation is
quite painless and may be carried out without any anaesthetic.

Many surgeons prefer to make the opening near the com-
mencement of the pelvic colon, because when a more distal
portion is used there is subsequently a distinct tendency to
prolapse of the mucous membrane. On the other hand, when
the opening is made in the lower part of the pelvic colon, the
proximal loop of the pelvic colon acts as a reservoir.

In some cases the pelvic colon and meso-colon are so short
that it is impossible to bring the bowel out at the abdominal
wound. It is then necessary either to mobilise the iliac colon
by dividing the peritoneum freely along the left paracolic gutter,
or to utilise the transverse colon or the caecum.

The Excision of a part of the pelvic colon presents little
difficulty when the gut possesses a long mesentery, and axial
anastomosis may be carried out. When the pelvic meso-colon

'2'2 c

344 THE ABDOMEN AND PELVIS

is short it may be necessary to mobilise the lowest portion of
the iliac colon. This can be effected by dividing the peritoneum
along the left paracolic gutter and stripping the bowel medially
on a hinge of peritoneum. The lateral cutaneous nerve of the
thigh; the ductus deferens, the internal spermatic vessels, and
the genito-femoral nerve may be injured unless care is exercised
at this stage of the operation. In addition, the ureter, which is
crossed by the root of the pelvic meso-colon near the apex of
the V, and the inferior mesenteric artery and its terminal branch
which runs downwards in the descending limb of the pelvic
meso-colon (Fig. 107), must all be preserved.

Transplantation of Ureters. — The mobility of the pelvic
colon renders it suitable for the implantation of the divided
ureters in cases of extroversion of the bladder and in epi-
spadias (in both sexes) with associated incontinence of urine
(Stiles). It might be supposed that the introduction of the
ureters into a septic tube would lead to an ascending infection
of the urinary tract, but provided that the urine, ureters, and
kidneys are healthy there is no risk of such an occurrence.
After the operation the bowels may be unnaturally loose for
a time, but the rectum rapidly becomes tolerant of the presence
of the urine so that the bowels act only once or twice a day.

The operation of transplantation is performed in two stages,
an interval of a fortnight being allowed to elapse before the
second ureter is transplanted.

Very careful preparation of the patient on each occasion is
essential to ensure an empty pelvic colon.

The patient is placed in an exaggerated Trendelenburg
position in order to facilitate the exposure of the ureters. A
vertical incision through the left rectus gives good access, due
care being taken to ligate the inferior epigastric artery. In
the case of the left ureter, the coils of small intestine are displaced
upwards, and the pelvic colon is identified. It is then turned
upwards, and the peritoneum in the floor of the intersigmoid
fossa (Fig. 107) is carefully divided. The pelvic portion of
the ureter is now exposed and may be traced downwards and
freed before it is ligated and divided. Its extremity is then
implanted into the ascending limb of the gut, and the adjacent
part of it is buried in the wall of the bowel after the manner
adopted in Witzel's gastrostomy. The peritoneal and abdominal
incisions are then closed.

The right ureter is found near the medial border of the right

THE ABDOMINAL CAVITY 345

psoas major, after it has been crossed by the root of the mesentery
(Fig. 107). The peritoneum over it is carefully incised, and it
is then traced downwards and divided. The cut end is then
approximated to the descending limb of the pelvic colon, and
the implantation is carried out as before.

In Ileo-Pelvic-Colostomy an anastomosis is established
between the terminal part of the ileum and the pelvic colon.
The operation is performed in chronic intestinal stasis, or for
threatened obstruction in the intervening parts of the large
bowel. It is carried out with the pelvis slightly elevated, and
good access is obtained by a median infra-umbilical incision.

Care must be taken to divide the ileum on the proximal side
of any obstructing bands (p. 325), and in such a way that it
can be connected to the pelvic colon without any subsequent
tension on the anastomosis. After the ileum has been cut
through, the mesentery is divided very slightly to facilitate the
invagination of the distal cut end of the gut. In bringing the
ileum into apposition with the pelvic colon, its cut end must be
rotated counter-clockwise in order that the left or lower surface
of the mesentery may lie in contact with the right surface of the
descending limb of the pelvic meso-colon. If the cut end is
rotated in the opposite direction, the enteric mesentery is
twisted and the ileum may subsequently become kinked. The
anastomosis between the cut end of the ileum and the side of
the descending limb of the pelvic colon is then completed. As
a result the anastomosis forms a bridge in front of a patent
passage between the mesentery and the pelvic meso-colon, and
in order to prevent the occurrence of an intra - peritoneal
strangulated hernia the two mesenteries are closely drawn
together by means of a linen-thread purse-string suture.

Development of the Intestines. — The alimentary canal caudal to the
stomach elongates much more rapidly than the posterior abdominal wall,
and the growth of the mesentery keeps pace with it. A U-shaped loop is
thus formed, which passes out of the abdomen through the patent umbilicus
(p. 288), carrying down the superior mesenteric artery between the two layers
of the mesentery. An evagination appears on the distal limb of the U and
subsequently forms the caecum and the vermiform process. Shortly after
its appearance the gut becomes rotated round the superior mesenteric artery,
so that the distal limb of the loop is carried across the ventral surface of the
proximal limb (Fig. 90). When the loop is withdrawn into the abdomen again
(p. 288) it is found that, as a result of this rotation, the transverse colon
crosses in front of the duodenum.

Thereafter, the mesentery of the large intestine partially disappears and
only persists for the transverse and pelvic cola. After the rotation the
transverse colon lies behind the greater omentum (p. 303), and its mesentery

346 THE ABDOMEN AND PELVIS

blends with the two posterior layers of the latter so that this part of the gut
attains the peritoneal relationship which is found in the adult.

The caecal outgrowth rapidly increases in length. Its proximal fourth
or less forms the caecum, and its distal part forms the vermiform process.
At birth the caecum is conical in shape and the vermiform process is attached
to its apex. This condition may persist — the infantile ccecum — but, normally,
the lateral wall of the caecum increases more rapidly than the medial wall,
and in the adult the vermiform process springs from the latter. After the
viscera are withdrawn from the umbilical cord (p. 288) into the abdomen,
the caecum lies in relation to the under surface of the liver in continuity with
the transverse colon. As the colon increases in length, the caecum gradually
descends, and at birth it lies in the right iliac fossa. Mai-descent or non-
descent is a well-recognised anomaly and the caecum is then frequently of the
infantile type. When it is not found in its normal position in abdominal
operations the possibility of this condition must be borne in mind.

Prior to the descent of the caecum the vermiform process may take up
a retro-caecal position, and it may become fixed in this situation, losing its
peritoneal covering. When the caecum descends the vermiform process is
left behind in the extra-peritoneal retro-caecal position (Fig. 104, 7).

Sometimes the rotation of the intestines is excessive, so that the caecum
is carried across the duodenum to its left side. It will then be found, together
with the vermiform process, between the two layers of the transverse meso-
colon, while the terminal part of the ileum occupies the areas in which the
caecum, ascending colon, and right colic flexure are normally found.

The mesenteries of the ascending, descending, and iliac cola often persist
during childhood and disappear later. This accounts for the incidence of
intussusception, in which the whole length of the large intestine commonly
possesses a mesentery. More rarely, an excess of peritoneum may persist
in the adult, and such a persistence may explain the condition of " mobile
caecum " and the accompanying " Jackson's veil " (p. 329).

The Kidneys lie, one on each side of the vertebral column,
opposite the twelfth thoracic, first, second, and third lumbar
vertebrae, but owing to the large size of the right lobe of the
liver the right one usually lies at a somewhat lower level than
the left. The kidney is about 2 inches wide and 4! inches long;
and its long axis is directed from above downwards and laterally.
The upper pole is limited above by a horizontal plane drawn mid-
way between the transpyloric plane and the xiphisternal junction;
the lower pole extends to the subcostal plane. The transpyloric
plane passes through the hila of both kidneys at about i \ inches
from the median plane. When the position of the hilum is
determined on the surface it is not difficult to map out the
kidney with the help of the facts which have been enumerated.

The Ureters may be indicated on the anterior abdominal
wall by lines drawn downwards from each hilum at a distance
of i£ inches from the median plane. These vertical lines
trisect the line joining the anterior-superior iliac spines at points
which correspond to the bifurcations of the common iliac arteries.
These vertical lines correspond to the abdominal parts of the

THE ABDOMINAL CAVITY 347

ureters and pass through the tips of the lumbar transverse
processes. The pelvic part of the ureter may be indicated by
a line which curves downwards and medially, with a slight

L.

FIG. 108. — Small Calculus impacted in the Right Ureter. The radiogram
was taken a few days after an attack of right renal colic. The outline
of the lower pole of the kidney is faintly visible. (Bythell and Barclay's
X-ray Diagnosis and Treatment. )

downward convexity, from the iliac bifurcation to the pubic
tubercle (spine).

Posteriorly, the transpyloric plane passes through the lower
border of the first lumbar spine. The hilum of the kidney lies

348 THE ABDOMEN AND PELVIS

1 1 inches lateral to the spine of the first lumbar vertebra, and
the whole kidney can be mapped out on the dorsal surface of
the body from the measurements already given.

FIG. 109. — Calcareous Lymph Gland, between the Transverse Processes of
the Fourth and Fifth Lumbar Vertebrae. The sacro-iliac joint is
well shown.

The abdominal part of the ureter corresponds to a line
drawn from the hilum to the postero - inferior iliac spine
(Fig. 84).

A knowledge of the topography of the kidneys and ureters
is essential for the correct interpretation of radiograms, in

THE ABDOMINAL CAVITY 349

which the question arises as to whether a certain shadow may
or may not be produced by a calculus.

The shadows thrown by phleboliths or calcareous deposits
in the mesenteric or iliac lymph glands may be difficult to
distinguish from shadows caused by ureteral calculi (Figs. 108
and 109). Phleboliths, however, are much more commonly
found in the vesico-prostatic veins (p. 365), but even in this
position they may throw shadows in relation to the vesical
openings of the ureters.

Although the normal line of the ureter passes through the
tips of the lumbar transverse processes, shadows found more
medially may nevertheless be due to ureteral calculi, because
when hypertrophied as the result of urinary obstruction, the
ureter takes an irregular downward course.

The peri-nephric fascia and the posterior relations of the
kidneys have already been described (p. 271).

The Right Kidney is in contact, anteriorly, with the
suprarenal gland, the liver, the right colic flexure, and the
duodenum. The suprarenal gland lies on its upper pole, and
below that, the liver covers nearly two-thirds of its anterior
surface. The second part of the duodenum lies along the medial
border overlapping the hilum, and the right colic flexure covers
the infero-lateral part of this surface. Over the hepatic area
the peritoneum is in direct contact with the kidney, forming
the posterior wall of the hepato-renal recess (p. 282) ; elsewhere
it is lifted off by the related viscera.

Excision of the Right Kidney may require to be performed
from the front, when the viscus is too large to be removed
through the loin. A long vertical incision is made through
the anterior abdominal wall, commencing above at the tenth
costal cartilage. Owing to the length of the wound, the ninth,
tenth, and eleventh intercostal nerves have to be sacrificed as
free access is essential. The abdominal cavity having been
opened, the peritoneum is incised along the upper part of the
right paracolic gutter and the hepato-renal recess. It is carefully
stripped off the hepatic area, and the ascending colon, right
colic flexure, second part of the duodenum, and the head of the
pancreas are turned medially. In this way the anterior surface
of the kidney is exposed, and the pedicle formed by the renal
artery and vein can be defined by careful blunt dissection.
The vein is the most anterior structure at the hilum and the
ureter and its dilated pelvis the most posterior, while the artery

350 THE ABDOMEN AND PELVIS

occupies an intermediate position. The ureter is ligated in two
places and divided. Next a ligature is passed round the vascular
pedicle and the artery and vein may then be ligated separately
nearer to the kidney. The viscus is removed, after it has been
separated from the surrounding peri-nephric fat.

In advanced tuberculous disease and hydronephrosis the
vascular supply may be much diminished, and it may be im-
possible to define the vascular pedicle owing to the presence
of adhesions. Care must be exercised in these cases not to exert
traction on the kidney, because the right renal vein, which is a
short vessel, may tear away from the inferior vena cava. This
risk can sometimes be avoided by splitting the capsule and
shelling out the kidney from inside. The bleeding vessels can
be secured as they are encountered, and subsequently portions
of the capsule can be cut away.

The Left Kidney is crossed at about the middle of its
anterior surface by the pancreas and splenic vessels (Fig. 87).
Above the pancreas, the left kidney is related to the spleen,
laterally, and to the suprarenal gland, medially. The area
between these two viscera lies in the posterior wall of the
omental bursa and forms a part of the stomach bed. Below the
pancreas, the first coil of the jejunum covers the whole surface
except a strip along the lateral border, which is in contact with
the left colic flexure and the descending colon.

The peritoneum is lifted off the kidney by the descending
colon, the pancreas, and the suprarenal gland, which are all in
direct contact with the viscus. The lieno- renal ligament
reaches the kidney above the pancreas, and its right layer is
continued over the gastric area, while its left layer covers the
area in contact with the spleen (Fig. 87). The area related
to the jejunum is covered by the downward continuation of the
lower layer of the transverse meso-colon.

It should be noted that the left kidney is found in three
regions, viz. (i) the omental bursa, (2) the left infra-colic
compartment, and (3) the lieno-renal recess, at the upper end
of the left paracolic gutter.

Excision of the Left Kidney is carried out by a method
very similar to that adopted for the right kidney. After the
abdominal cavity has been opened, the peritoneum in the upper
part of the left paracolic gutter, the phrenico-colic ligament,
and the peritoneum along the upper part of the lateral border
of the kidney are all incised. The descending colon and left

THE ABDOMINAL CAVITY 351

colic flexure are then stripped medially and the whole of the
anterior surface of the kidney can be exposed.

The peritoneum must not be incised along the medial border
of the bowel lest the colic vessels be injured. Further, in the
excision of either kidney, the possible presence, generally at the
lower pole, of one or more supernumerary renal arteries must be
remembered.

The trans-peritoneal operation for excision of the kidney
possesses one great advantage over the lumbar or extra-peritoneal
operation, namely, that the surgeon is able to palpate both
kidneys through the incision in the abdominal wall.

Structure of the Kidney, — The hilum of the kidney leads into a space,
termed the renal sinus, into the cavity of which numerous renal papillae
project. On section, the kidney is seen to possess a narrow cortical and a
deeper medullary layer. The latter is darker in colour and striated in appear-
ance, and is subdivided into a number of small pyramids, the apices of which
constitute the renal papillae.

At the hilum the ureter becomes greatly dilated to form the renal pelvis
(pelvis of ureter), which divides into two or sometimes three calyces majores.
Each calyx major subdivides into smaller calyces, and each of the latter is
associated with one or more renal papillae, receiving the urine from the
uriniferous tubules which open on their surfaces.

Calculi may form in the kidney, calyces, or renal pelvis,
and give rise to hydronephrotic changes by obstructing the
urinary outflow ; on the other hand, a stone may lie latent for
a considerable period.

A stone or stones lying in the renal pelvis may be removed
by incising the pelvis and without cutting into the kidney.
This is best carried out by the lumbar route, and after the kidney
has been brought to the surface, it is turned slightly forwards
and the pelvis is incised horizontally. Occasionally one or
more of the renal vessels may intervene, but these may be
retracted out of the way. The pelvis heals extremely readily,
and there is no danger of establishing a fistula.

The Renal Arteries arise from the aorta a little below the
transpyloric plane. The right one passes behind the vena cava
inferior, the head of the pancreas, the second part of the
duodenum, and its own vein. The left one passes behind the
body of the pancreas and the left renal vein.

In the renal sinus the terminal branches of the renal artery
divide into ventral and dorsal groups. Brodel has pointed out
that an incision along the convex lateral margin of the kidney
cuts through the principal arteries of the ventral group, and he
suggests that incisions should be made slightly behind that

352 THE ABDOMEN AND PELVIS

border so as to pass between the two groups. When this is
done successfully, the haemorrhage is not so great, and it is
easily controlled by compression of the vascular pedicle.

Supernumerary renal arteries may be present on either side.
They usually arise from the aorta and enter the medial border

FIG. no. — Calculus in the Renal Pelvis. The twelfth rib is almost entirely
obscured by the large calculus. A smaller calculus is present in the
lower pole of the kidney.

of the kidney near its lower pole. Sometimes they ascend from
the common iliac or they may arise above the normal renal and
enter the upper pole. Their occurrence must always be borne
in mind in excision of the kidney.

i . The Renal Veins terminate in the inferior vena cava at the
transpyloric plane. Owing to the position of the vena cava on
the right side of the vertebral column, the right renal vein is
much shorter than the left, and it is consequently liable to be

THE ABDOMINAL CAVITY 353

torn away from the vena cava during the manipulations necessary
in excision of the right kidney. The left renal vein lies behind
the pancreas, and crosses in front of the aorta and behind the
superior mesenteric artery. It receives the left suprarenal and
the left spermatic veins (p. 264).

Movable Kidney. — Under normal conditions the kidney
cannot be palpated, although it moves slightly with respiration.
Sometimes the movement may become so increased in amount
as to give rise to distressing symptoms from kinking of the
ureter. When this condition is suspected, the patient should
first be examined in the recumbent and then in the semi-
recumbent -or in the sitting posture. The surgeon places one
hand in the interval between the last rib and the iliac crest
and the other on the anterior abdominal wall, and the patient
is then instructed to take a deep breath. As the abdominal
wall collapses with expiration, the surgeon gently presses the
tips of his fingers in below the costal margin and attempts to
catch the kidney between his two hands. In minor degrees of
mobility only the lower pole of the kidney may be felt, as it
slips upwards from the tips of the fingers, but when the condition
is marked, the whole kidney may be caught, or the fingers may
even be made to meet above its upper pole.

The right kidney is more often at fault than the left, and a
movable right kidney must not be confused with an enlarged
gall-bladder (p. 313). On either side an ovarian cyst which
possesses a long pedicle may be mistaken for a movable kidney.
This is owing to the fact that the surgeon, on examination, is
able to manipulate the tumour into the position which the
kidney normally occupies. When a movable kidney has been
replaced in this way, it tends to maintain its position, but an
ovarian cyst soon sinks down again towards the pelvis.

The Ureter is about ten inches long. It commences at the
renal pelvis and is somewhat constricted at its point of origin.
It descends on the anterior surface of the psoas major, which
separates it from the tips of the transverse processes of the
lumbar vertebrae, and enters the pelvis by crossing the bifurcation
of the common iliac, or the external iliac artery near its com-
mencement.

On the right side, the ureter lies behind the peritoneum of
the right infra-colic compartment, but before it enters the
pelvis it is crossed by the root of the mesentery and the terminal
part of the ileum. At its upper end it lies behind the second

23

354 THE ABDOMEN AND PELVIS

and third parts of the duodenum ; between the latter and the
root of the mesentery, the right colic, spermatic, and ileo-colic
vessels cross its anterior surface and separate it from the
peritoneum (Fig. 107). On account of these relations the
lumbo-ilio-inguinal route (p. 274) for exposure of the ureter is
to be preferred to the trans-peritoneal route.

On the left side, the ureter lies behind the peritoneum of the
left infra-colic compartment, and as it enters the pelvis it is
crossed by the pelvic meso-colon. The left colic, spermatic,
and sigmoid vessels cross its anterior surface (Fig. 107).

The blood-supply of the ureter is derived from the renal,
spermatic, superior, and inferior vesical arteries. These branches
anastomose freely with one another, and as a result large segments
of the ureter can be freed without any subsequent sloughing.

The nerve-supply of the renal pelvis and the ureter is derived
from the eleventh and twelfth thoracic and the first and second
lumbar segments. In renal colic strong waves of contraction
pass down the ureter, and the pain is successively referred to
the skin areas supplied by these segments. When the calculus
is situated in the renal pelvis, the pain begins in the loin in the
area supplied by T. n, and passes obliquely round the lower
part of the abdominal wall affecting the areas supplied by
T. 12 and L. i (ilio-hypogastric). Sometimes the pain shoots
into the testis, and testicular hypersesthesia may persist after
the attack. This is due to the sensory branch which the external
spermatic (genital branch of genito-crural) nerve (L. i and 2)
gives to the tunica vaginalis testis (Mackenzie). At the same
time, the afferent impulses from the strongly contracting ureter
may excite a viscero-motor reflex (p. 251). The lower portions
of the lateral abdominal muscles become rigid, and the cremaster
muscle may contract and draw the testis up towards the
subcutaneous inguinal ring. All the muscles affected are
innervated from the same segments as supply the skin areas
over which the pain is felt. The viscero-sensory reflex may
also affect the lumbo-inguinal nerve (crural branch of genito-
crural) and the posterior rami of the upper lumbar nerves so
that pain is experienced in the front of the thigh and in the
buttock.

THE PELVIS 355

THE PELVIS.

The Pelvis Minor (True Pelvis).— The walls of the
pelvis consist of three layers : (i) a bony and ligamentous
stratum, (2) a muscular stratum, and (3) a fascial stratum.

1. The osseous circle, formed by the sacrum, the coccyx,
and the hip bones, is strengthened by the sacro-tuberous and
sacro-spinous ligaments (great and small sacro-sciatic), which
connect the sacrum and coccyx with the ischium. In the pubic
arch this layer is represented by the inferior fascia of the
urogenital diaphragm (anterior layer of triangular ligament).

2. The muscular layer consists of : (a) the obturator internus,
which arises from the side wall of the pelvis and passes through
the lesser sciatic foramen (p. 419) ; (b) the piriformis, which arises
from the front of the sacrum and passes through the greater
sciatic foramen ; and (c) the sphincter of the membranous
urethra (compressor urethrae), which assists in rilling the gap
between the inferior rami of the pubes.

3. The fascia which covers these muscles is termed the
parietal pelvic fascia. It is continuous above with the fascia
lining the abdomen and is attached below to the margins of
the inferior pelvic aperture.

The large nerves of the lumbo-sacral and sacro-coccygeal
plexuses lie between the muscular and fascial strata, but the
large blood-vessels -lie under the peritoneum internal to the
fascia, and with the exception of the obturator artery (p. 411),
pierce it as they leave the pelvis through the various foramina.
The points at which they pass through the fascia are the sites
of pelvic hernise.

Fractures of the Pelvis are usually caused by severe
crushing, and they occur at the weakest areas of the bony ring,
namely, the pubic and ischial rami, where they bound the
obturator foramen, and the sacrum, along the line of the sacral
foramina. Rectal or vaginal examination will often disclose
the extent of the fracture and may assist the surgeon to obtain
the correct alignment of the displaced fragments. Serious
complications arise if the sharp broken edges wound any of the
pelvic viscera.

The Parietal Pelvic Fascia covers the piriformis, the ob-
turator internus, and the sphincter of the membranous urethra.

356 THE ABDOMEN AND PELVIS

The obturator internus arises from the posterior part of the
ilio-pectineal line, and over this area the parietal pelvic fascia
is directly continuous with the abdominal fascia covering the
psoas major (p. 271). More anteriorly, the upper border of
the obturator internus gradually sinks to a lower level and
carries the parietal pelvic fascia with it ; so that the inner
surface of the superior ramus of the pubis is left uncovered by
fascia or muscle. Opposite the obturator foramen, the fascia
is carried over the upper border of the obturator internus
and blends with the upper margin of the obturator membrane.
In the region of the pubic arch it forms the superior fascia of
the urogenital diaphragm (deep layer of triangular ligament]
(Fig. 115), and its upper border blends with the upper border of
the inferior fascia of the urogenital diaphragm (p. 378), leaving
a small interval below the pubic symphysis for the passage of
the dorsal vein of the penis.

The lower margin of the parietal pelvic fascia blends, in
front, with the free edge of the inferior fascia of the urogenital
diaphragm and the fascia of Colles (p. 376) ; posteriorly, it
is attached to the sacro-tuberous ligament and the ischial
tuberosity.

The Pelvic Diaphragm stretches across the cavity of the
pelvis, dividing it into an upper part, the pelvis proper, and a
lower part, which is dealt with under the Perineum (p. 373).
It is formed by the two levatores ani and coccygei, with the fascia
covering them, but it is incomplete, as gaps are left for the
passage of the anal canal and the urethra and, in the female,
for the vagina also.

The Levator Ani has a linear origin from the side wall of the
pelvis. Its posterior fibres are attached to the ischial spine ;
the intermediate fibres arise from the parietal pelvic fascia
along a line extending from the ischial spine to the anterior
border of the obturator foramen. The anterior fibres arise
from the pelvic surface of the body of the pubis above the level
of the parietal pelvic fascia, but they do not extend as far as
the symphysis.

The posterior fibres pass medially and are inserted into the
coccyx. In front of that point the muscles of the two sides
meet in a median raphe and form a muscular sling, which
supports the lower end of the rectum. The anterior fibres pass
backwards lateral to the prostate, which separates them from
the muscle of the opposite side, and they extend downwards

THE PELVIS 357

along the outer surface of the anal canal to blend with its
muscular coat between the internal and external sphincters

(P- 369)-

A collection of muscular fibres extending antero-posteriorly

between the pelvic surface of the urogenital diaphragm and
the upper end of the anal canal is termed the Recto-urethralis
muscle (p. 369).

In the female the anterior borders of the two leva tores ani
pass one on each side of the vagina and act as a sphincter
muscle.

The principal action of the levator ani is to assist defgecation
by drawing the anal canal upwards over the fsecal mass, thus
assisting in its expulsion.

Its nerve-supply is derived from the perineal division of the
internal pudendal (S. 2, 3, 4) and directly from S. 3 and 4.

The Coccygeus is a small muscle which overlaps the posterior
border of the levator ani. It extends from the ischial spine to
the sides of the sacrum and coccyx, and helps to complete the
pelvic floor.

The Visceral Pelvic Fascia forms the upper layer of the
pelvic diaphragm and covers the pelvic surfaces of the levatores
ani and the coccygei. Opposite the pubic symphysis, where
the two levatores leave a gap, the fascia forms a continuous
sheet from side to side. It is very weak in the middle line, but
is specially thickened at each side, where it extends backwards
to the prostate and the bladder, forming the true pub o-pro static
ligaments (anterior pedicles of the bladder). Elsewhere, its
circumferential attachment corresponds to the linear origin
of the muscles of the pelvic diaphragm.

When it is traced inwards from the sides, it is found to be
in contact with the various pelvic viscera, which it provides
with fibrous coverings. On account of this relationship the
visceral pelvic fascia is described as consisting of rectal, recto-
vesical, and vesical portions.

Anteriorly the visceral pelvic lascia is specially thickened to
form a strong fibrous sheath for the prostate gland.

The Pelvic Peritoneum is separated from the pelvic dia-
phragm by the pelvic viscera and blood-vessels. It covers the
front and sides of the upper two-thirds of the rectum (p. 368)
and is then reflected forwards on to the upper part of the
posterior surface of the urinary bladder, forming the floor of
the recto-vesical fossa. It covers the superior surface of the

358 THE ABDOMEN AND PELVIS

bladder and is reflected from its apex on to the anterior abdominal
wall.

The Urinary Bladder occupies the anterior part of the
pelvic basin and lies immediately behind the pubes. When
empty it is somewhat pyramidal in shape, with an apex, a base,
a superior, and two infero-lateral surfaces.

The apex of the bladder is directed forwards and upwards
and is in contact with the pubic symphysis. An impervious
fibrous cord, known as the urachus (p. 381), passes upwards
from the apex to the umbilicus in the extra-peritoneal fat.

The base or posterior surface is directed backwards and

,. Ureter

___ Membranous urethra

FIG. in. — Basal aspect of Bladder, Seminal Vesicles, and Prostate,
hardened by formalin injection.

slightly downwards towards the rectum. It is roughly triangular
in shape ; the inferior angle is truncated and corresponds to the
internal orifice of the urethra, while the supero-lateral angles
are joined by the ureters. In the middle line the two ductus
deferentes lie side by side in apposition with this surface and
separate the seminal vesicles from one another (Fig. in). These
parts of the genital tract are embedded in visceral pelvic fascia
and intervene between the basal surface of the bladder and the
rectum. A small interval, however, exists between the ductus
deferentes near the upper border, and it slightly increases in
size as the bladder becomes distended. Through this area the
trochar was passed in puncture of the bladder by the old-fashioned
rectal route.

THE PELVIS 359

The superior surface is entirely covered by peritoneum
and is related to coils of small intestine or pelvic colon. Along
its lateral borders the peritoneum is reflected on to the pelvic
walls as the so-called lateral false ligaments of the bladder.

The infero-lateral surfaces are related in front to the bodies
of the pubes and the retro-pubic pad of fat. Posteriorly they
are in contact with the upper parts of the obturator internus and
levator ani muscles.

The neck of the bladder is situated where the infero-lateral
and posterior surfaces meet one another. It is pierced by the
urethra and is partly continuous with the prostate.

When the bladder distends, it becomes more or less ovoid in
shape. The neck and posterior surface are not much affected
but the infero-lateral and superior surfaces become greatly
stretched, and the upper part of the bladder comes to lie in the
abdomen. This increase in size does not involve any stretching
of the vesical peritoneum, for, as the bladder rises into the
abdomen, it strips the peritoneum off the lateral pelvic and
anterior abdominal walls. In this way the anterior part of the
infero-lateral surfaces comes to lie in direct contact with the
anterior abdominal wall, no peritoneum intervening. In aspirat-
ing the over-distended bladder supra-pubically, the surgeon takes
advantage of this alteration in the disposition of the peritoneum,
and in the operation of supra-pubic cystotomy the same condition
is obtained by distending the bladder artificially.

In the infant, the bladder occupies a higher position than it
does in the adult owing to the smaller relative size of the pelvis
and the greater relative size of the bladder itself. The internal
orifice of the urethra lies almost on a level with the upper border
of the pubic symphysis, and most of the bladder is situated in the
abdomen. This difference must be borne in mind when opening
the abdomen in the infant, and care should be taken to see that
the bladder is evacuated before making an incision in the lower
part of the anterior abdominal wall.

The retro -pubic pad of fat occupies the space of Retzius,
which is bounded in front by the symphysis pubis, behind by
the bladder, and below by the true pubo-prostatic ligaments.
In extra-peritoneal rupture of the bladder the extra vasated urine
collects temporarily in this space (p. 378).

Supra -Pubic Cystotomy is commonly performed for the
removal of calculi, tumours, and soft, enlarged prostates capable
of easy enucleation. The bladder is emptied, and then filled

360 THE ABDOMEN AND PELVIS

with warm boracic lotion as a preliminary measure, its capacity
having been estimated prior to anaesthesia so as to exclude the
risk of over-distension. In this way the bladder is brought into
direct contact with the lower part of the anterior abdominal

FIG. 112 — Vesical Calculus, Antero-posterior View. Observe the positions
of the calculus and the ischial spines relative to the sacrum.

wall, no peritoneum intervening (p. 359). A transverse incision,
about four inches long, is made a little above the pubes This
passes through the skin and fasciae and exposes the linea alba
and both rectus sheaths. A vertical incision is made in the linea
alba, and the two recti are retracted. If satisfactory access is
not obtained, the muscles may be elevated from their pubic
attachments so that they can be more widely separated.

THE PELVIS 361

The fascia transversalis is divided and the bladder is exposed
in the extra-peritoneal fat. The fingers are then passed upwards
until the line of peritoneal reflection is met, and the peritoneum
is then further elevated from the bladder., In order to prevent
the bladder from collapsing into the pelvis when it is incised,
two retention sutures are passed through its wall and are held
by an assistant during the operation. The bladder may now
be incised, and the calculus, tumour, etc., removed.

The muscular coat of the bladder is very strongly
developed. Near the neck the outer fibres become continuous
with the muscular tissue of the prostate ; the intermediate
fibres are increased in number and form the sphincter vesicse
internus ; the inner layer becomes continuous with the
longitudinal muscular coat of the urethra.

The mucous lining of the bladder is not so elastic as
the muscular coat, and is thrown into rugae when the bladder is
empty. This is permitted by the laxity of the submucosa ; but
over a triangular area which corresponds to the basal surface,
the mucous coat is smooth and firmly adherent to the muscular
wall. This area is referred to as the internal trigone : its superior
angles correspond to the openings of the ureters, and its inferior
angle to the internal orifice of the urethra, which is i\ inches
from the opening of either ureter. The ureters pierce the
bladder wall very obliquely, and when the intra-vesical pressure
is increased as the bladder fills, this arrangement provides a
valve -like action, which prevents a reverse flow towards the
kidneys. The ureteral openings are about two inches apart and
are connected by a ridge of mucous membrane called the inter-
ureteric bar.

In hypertrophy of the muscular coat}to overcome the obstruction
caused by stricture of the urethra, prostatic enlargement, etc.,
small pockets of mucous membrane may be formed in the
intervals between the bands of enlarged fibres. These loculi
sometimes form distinct diverticula, and they tend to retain
urine, which decomposes and gives rise to calculus formation.
The presence of incarcerated stones in the bladder wall can be
accounted for in this way.

The Arteries of the bladder are derived from the hypogastric
(internal iliac) artery by means of three paired vessels, the
superior, middle, and inferior vesical arteries.

Together with the ureter, lymphatics, and nerves, the
arteries and veins of each side are embedded in a sheet of visceral

362 THE ABDOMEN AND PELVIS

pelvic fascia, which passes forwards and medially to the lateral
border of the posterior surface of the bladder and constitutes
its posterior pedicle.

The vesical arteries supply the bladder, the seminal vesicles,
the prostate and the terminal parts of the ureters. In addition
the superior vesical usually gives off a special branch to the
ductus deferens (p. 257).

The vesical veins join the pudendal (prostatic) plexus (p. 366),
from which two or three large veins issue in the posterior pedicle
of the bladder to join the hypogastric vein.

The nerve-supply of the bladder is derived entirely through
the sympathetic. Some of the fibres come from the twelfth
thoracic and first lumbar segments ; the others arise from the
second and third, or third and fourth sacral segments, and are
restricted to the basal surface and the trigone. On account
of the different segments involved, pain referred from the
bladder is felt in two different regions. A vesical calculus
irritates the trigone, and the pain is referred to the perineum
and the penis (S. 2, 3, and 4). On the other hand, pain due to
over-distension or caused by strong contraction of the muscular
wall, such as occurs at the end of micturition in cases of vesical
calculus, is usually referred to the lower part of the anterior
abdominal wall (T. 12, L. i).

In the presence of vesical calculi or ulcers of the bladder
wall, the centres for micturition in the spinal medulla become
hypersensitive, and frequency of micturition results.

The Pelvic Part of the Ureter is closely related to the
peritoneum. It crosses the brim of the pelvis in front of, or a
little lateral to, the bifurcation of the common iliac artery, and
descends in front of the hypogastric (internal iliac) artery, which
separates it from the posterior wall of the pelvis and the great
nerve trunks. As it approaches the base of the bladder, it
curves medially and enters the posterior pedicle. Here it is
related to the superior vesical artery, which lies above it, and
the other vesical arteries and veins, which lie below it. Just
before entering the bladder (p. 358), the ureter is crossed
latero-medially and on its superior aspect by the ductus deferens,
which intervenes between it and the peritoneum.

This part of the ureter is supplied by the vesical arteries.

Impacted calculi in the pelvic part of the ureter are usually
found (i) at the pelvic brim, on a level with the first sacral
vertebra, or (2) at the point of entrance into the bladder, on a

THE PELVIS

363

level with the first coccygeal vertebra, because the lumen of
the tube is distinctly narrower at these two points. When a
radiogram shows a shadow which might be an ureteral calculus,
its horizontal level is of as great importance as its vertical plane
as an aid to differential diagnosis.

FIG. 113. — Radiogram showing the lower abdominal and the pelvic portions
of the Ureters, displayed by the introduction of bougies.

The surgical approach for the removal of an impacted ureteral
calculus may be either retro-peritoneal or infra-peritoneal.

Calculi impacted near the pelvic brim are best approached
by the retro -peritoneal route (p.' 274).

Infra-peritoneal Route. — In order to obtain access to the
terminal part of the ureter, an oblique incision, which is directed
downwards and medially, is made through the lower part of
the anterior abdominal wall^(Fig. 71). In its medial two-thirds
this incision crosses the rectus muscle below the level of the
linea semicircularis (of Douglas). The aponeuroses of the

364 THE ABDOMEN AND PELVIS

external oblique, internal oblique, and transversus are divided,
in turn, in the lateral part of the wound, whilst medially the
anterior wall of the rectus sheath is divided and the muscle is
retracted in a medial direction. The transversalis fascia is
now exposed, and the inferior epigastric artery, which may be
ligated if necessary, is found on its surface in the medial part
of the wound.

The fascia transversalis is torn through in the neighbourhood
of the bladder, and the peritoneum is retracted upwards and
medially. In this way the abdominal viscera are kept out of
the field of operations and more space is obtained. When the
peritoneum is elevated, the external iliac vessels are exposed in
the posterior part of the wound, and the ductus deferens is seen
in front, as it descends to reach the seminal vesicles (p. 358).
In this part of its course the ureter is not adherent to the
peritoneum, but is closely related to the structures on the pelvic
wall. The superior vesical artery forms a convenient guide,
since it lies anterior to the ureter. As a small calculus, impacted
in the terminal portion of the ureter, may be extremely difficult
to feel, an assistant pushes the bladder upwards by means of
a finger in the rectum. The surgeon then presses the ureter
against the resistance thus afforded, and determines the precise
position of the stone.

Calculi impacted in the vesical orifice of the ureter may be
removed trans-vesically (cf. removal of gall-stones impacted in
ampulla of Vater, p. 317).

The Prostate consists chiefly of plain muscle fibres and
glandular tissue, surrounded by a fibrous capsule. The muscle
fibres are directly continuous with the external stratum of the
muscular coat of the bladder. The prostate possesses a strong
fibrous sheath, which is derived from the visceral pelvic fascia
and is quite distinct from the capsule. This sheath does not
intervene between the prostate and the bladder, but is carried
upwards on to the walls of the latter.

In size and shape the prostate resembles a chestnut. Its
base is directed upwards and is partly continuous with the neck
of the bladder ; its apex is directed downwards and rests on the
superior fascia of the urogenital diaphragm. The posterior surface
is in contact with the rectum and can readily be palpated on rectal
examination. The lateral surface is crossed by the anterior border
of the levator ani and can also be examined from the rectum.

The prostate encloses the first part of the urethra, which

THE PELVIS 365

pierces its base, traverses its substance, and emerges a little
above its apex. It is also pierced by the common ejaculatory
ducts (p. 367).

A well-marked groove separates the prostate from the
bladder externally. At this level the prostatic sheath contains
in its walls the pudendal (prostatico-vesical) plexus of veins, which
receives the dorsal vein of the penis (p. 386), and tributaries
from the bladder and prostate. The prostatic veins cross the
potential interval between the capsule and the sheath to reach
the plexus, and are consequently torn in prostatectomy.
(Compare this arrangement with the course of the thyreoid
veins, p. 168.)

The pudendal plexus terminates in the large veins which
have already been mentioned in connection with the posterior
pedicle of the bladder (p. 362).

Hypertrophy of the Prostate usually involves the glandular
tissue, and may be confined to the " middle lobe " ; but the whole
prostate may become enlarged. The dense, unyielding character
of the sheath limits the growth in antero-posterior and lateral
directions, but the neck of the bladder offers little resistance
to upward extension. As a result the prostatic tissue projects
into the bladder through the internal sphincter and forms a
collar-like elevation around the internal urethral orifice. The
muscular tissue which connects the prostate and the bladder is
stretched and thinned out, so that few or no fibres are encountered
by the surgeon in prostatectomy (p. 366), and the tumour is
exposed as soon as the mucous membrane over it has been torn
through.

Owing to the direction of growth the prostatic urethra
becomes increased in length from ij to 2 or 2^ inches, and at
the same time its forward concavity becomes proportionately
greater.

The so-called " middle lobe " of the prostate is that part
which intervenes between the ejaculatory ducts (p. 367) and
the urethra. Its upper surface lies under the mucous coat
of the tiigone of the bladder, immediately behind the internal
urethral orifice, and when well marked produces a slight elevation
known as the uvula vesicce. When hypertrophy affects the
middle lobe only, the prostate is apparently normal on rectal
examination. In these cases the enlarged uvula seriously
hinders the escape of urine through the internal urethral orifice
and constitutes one of the worst forms of urinary obstruction.

366 THE ABDOMEN AND PELVIS

Effects of Prostatic Hypertrophy. — The upward growth
of the prostate weakens the internal sphincter of the bladder
so that urine enters the urethra more easily and the desire to
micturate is more frequent.

A pouch gradually forms behind the collar -like elevation
which surrounds the internal urethral orifice, and the urine
which it contains can only be evacuated by straining. As the
tumour increases in size, the pouch becomes deeper and attempts
to evacuate it merely crush down the projection over the orifice
of the urethra. The urine in this part of the bladder cannot
be passed, and is termed " residual urine." The straining
causes hypertrophy of the muscular wall, and for a time this
may assist micturition. Ultimately, however, the increasing
amount of residual urine leads to dilatation of the bladder,
and urine can only be passed by the contraction of the abdominal
muscles. The quantity passed at one time is necessarily small,
so that the bladder remains constantly distended. This
condition may come on very gradually, and the patient, being
totally unaware of its nature, only complains of symptoms
which are referable to chronic auto-intoxication.

Attacks of prostatic congestion are followed by complete
retention of urine and still further dilatation of the bladder,
which may never regain its muscular tone. The rapid evacuation
of a greatly distended and dilated bladder by the passage of a
catheter may be followed by severe haemorrhage, as the weakened
muscular wall, when relieved of its internal pressure, is unable
to contract, and the vessel-walls, being unsupported, give way.

Supra-Pubic Prostatectomy. — A catheter is first passed
into the bladder, and the viscus is then opened by the method
outlined on p. 359. The surgeon inserts his finger, and guided
to the internal urethral orifice by the instrument, he scrapes
through the mucous coat overlying the prostate with his finger-
nail. At the same time the surgeon may pass the index finger
of his free hand, suitably protected, into the rectum and use it
as a guide and support for his manipulations inside the bladder.
Owing to the thinning out of the muscular tissue (p. 365) the
tear in the mucous coat at once exposes the prostate, and
the surgeon thrusts his finger through into the interval between
the capsule and the sheath. This interval is defined by sweeping
the finger first round one side of the prostate and then round the
other. In the process the prostatic veins are torn through as
they pass outwards to join the pudendal plexus. The prostate

THE PELVIS 367

is now only fixed by the distal end of the prostatic urethra,
and this is torn across as it pierces the urogenital diaphragm.

If the surgeon fails to define the interval between the capsule
and the sheath and penetrates the latter with his finger-nail,
severe haemorrhage results from the thin-walled veins of the
pudendal plexus and its vesical tributaries. The condition is
accentuated if the surgeon continues to attempt enucleation
with his finger in the wrong stratum.

b Drainage is obtained by a wide supra-pubic tube, but in the
presence of cystitis some surgeons make use of a perineal drain
in addition. A pair of long forceps is inserted through the
supra-pubic wound into the cavity of the prostatic sheath and
cut down on in the perineum. A tube is then drawn upwards,
and the whole cavity can be washed out thoroughly. An
advantage of this additional drain is that it prevents absorption
from the accumulation of septic urine and blood-clot in the raw
area.

As a result of the removal of the prostate, the first part of
the urethra is replaced by a fibrous sac — the prostatic sheath.
The neck of the bladder opens into it above and the urethra
opens out from it below. This cavity soon collapses and its
walls gradually become lined by mucous membrane, which grows
upwards from the torn urethra and downwards from the bladder.

The Seminal Vesicles lie obliquely on the basal surface of
the bladder • their upper extremities are widely separated and
their lower extremities are close together. Posteriorly, they
are related to the anterior surface of the rectum, and only
visceral pelvic fascia intervenes. The upper, blind end of the
seminal vesicle lies immediately under the floor of the recto-
vesical peritoneal fossa and close to the termination of the
ureter. Its lateral border is closely applied to the medial
aspect of the posterior pedicle of the bladder, and its medial
border is related to the ductus deferens (Fig. in).

Inferiorly the seminal vesicle narrows to form the excretory
duct, which joins the ductus deferens to form the common
ejaculatory duct. The two ejaculatory ducts pass downwards
and forwards through the substance of the prostate and open
into the prostatic urethra close to the orifice of the prostatic
utricle (p. 383).

The Rectum begins opposite the third piece of the sacrum
as the direct continuation of the descending limb of the pelvic
colon. It is about five inches long and curves downwards and

368 THE ABDOMEN AND PELVIS

forwards to a point a little above the apex of the prostate,
where it bends sharply backwards and downwards, over the
anterior decussating fibres of the levatores ani, to form the anal
canal. The expanded lower part of the rectum is termed the
ampulla and is better marked in the female than in the male.

In its upper third the rectum is clothed by peritoneum
anteriorly and on each side ; in its middle third it is only covered
anteriorly ; its lower third lies below the line of reflection of
the peritoneum from the rectum to the bladder (p. 357) and is
consequently devoid of any peritoneal covering (Fig. 115).
The upper two-thirds of the rectum is related anteriorly to the
coils of small intestine, or pelvic colon, which occupy the recto-
vesical fossa and separate it from the bladder, and tumours of
the pelvic colon may sometimes be palpated per rectum. In
front of the lower third of the rectum lie the seminal vesicles,
ductus deferentes and the prostate, embedded in visceral pelvic
fascia (Fig. 115).

As it descends following the curvature of the sacrum and
coccyx, the rectum exhibits three lateral flexures , the uppermost
and lowermost being directed to the left and the middle one
to the right. As a result, the rectum is not median in position
but projects to the left side of the middle line. On the concavity
of each bend, a crescentic fold, consisting of the mucous and
circular muscular coats, projects within the lumen of the gut
and stretches almost halfway round it. These folds are known
as the plicce transversales recti (rectal valves), and they serve to
support the faeces and to prevent over-distension of the ampulla.
Scybalous masses supported by the lowest fold, which lies at
about three inches from the anus, can be reached by the tip
of the finger on rectal examination, but, as they cannot be
completely examined, care must be taken not to mistake them
for a malignant tumour. The plicae transversales recti can
easily be seen on examination with the sigmoidoscope when
the bowel has been artificially distended, but even then they
may tend to obstruct the passage of the instrument.

Posteriorly, the upper two-thirds of the rectum is in contact
with the sacrum and coccyx in the median plane, and, on each
side, overlaps the piriformis muscle and the nerves of the sacral
plexus, from which, however, it is separated by the parietal
pelvic fascia and its own covering of visceral pelvic fascia.
When loaded, the rectum may exert pressure on the nerves,
especially of the left side, and produce the painful symptoms

THE PELVIS 369

of sciatica. The lower third of the rectum rests on the pelvic
floor (p. 356) and is surrounded by the rectal layer of the visceral
pelvic fascia.

The hypogastric (internal iliac) vessels,, and lymph glands
and the ureters are related to the sides of the rectum, but the
latter are only in contact with its wall when the gut is con-
siderably distended.

Structure of the Rectum. — The submucous coat consists of very loose
areolar tissue, and, as a result, the mucous coat may become prolapsed through
the anus, following violent straining.

The circular muscular coat forms a complete covering for the gut but
the longitudinal coat is arranged in two broad bands, which lie one on its
anterior and the other on its posterior surface. The shortness of these bands,
relative to the length of the mucous and circular muscular coats, accounts for
the production of the lateral flexures of the rectum.

The Anal Canal, which is about one and a half inches long,
passes downwards and backwards from the rectal ampulla to the
anus. Except during defaecation, its walls are kept in apposition
by the action of the levatores ani and sphincter muscles. The
sides of the anal canal are in relation to the elastic pads of fat
which occupy the ischio-rectal fossae (p. 373). Anteriorly, the
anal canal is related to the urogenital diaphragm, the
membranous part of the urethra and the bulb of the penis
(Fig. 115). The surgeon takes advantage of this relation when
he is negotiating a bougie through a difficult stricture of the
urethra. By inserting the forefinger of his left hand into the
rectal ampulla, he can control the point of the instrument and
can recognise at once if it is making a " false passage." Further,
in supra-pubic prostatectomy, the enucleating finger of the
right hand within the bladder will be greatly assisted if the
surgeon passes his left forefinger into the ampulla of the rectum.

The recto-urethralis muscle extends from the anterior surface
of the upper end of the anal canal to the superior fascia of the
urogenital diaphragm. When it has been cut transversely,
the finger can be inserted into a loose cellular interval which
lies between the rectum and the prostate, and these two viscera
can then be easily separated. Section of the recto-urethralis
is an important step in the operations of prostatectomy and
excision of the rectum by the perineal route (p. 379).

The muscular coat of the anal canal is very strongly
developed. The circular fibres of the rectum are continued
downwards to form the internal sphincter, which clothes the
upper two-thirds of the canal. The levatores ani lie external

24

370 THE ABDOMEN AND PELVIS

to the internal sphincter and some of their fibres are prolonged
downwards in the wall of the anal canal. The external sphincter
lies very superficially, and is attached to the tip of the coccyx
behind and to the central point of the perineum in front.

The submucous coat of the anal canal is very lax and
contains tributaries of the haemorrhoidal veins.

The mucous coat of the anal canal is loosely attached to
the muscular wall and, in its upper part, is thrown into a number
of vertical folds, termed the rectal columns (of Morgagni). These
are united at their lower ends by small semilunar folds, which
are termed the anal valves. Ball suggests that anal fissure is
produced by the tearing downwards of one of the anal valves
by a scybalous mass.

The line formed by the anal valves, sometimes termed
the pectinate line, marks the junction between the columnar
epithelium of the intestinal canal and the scaly epithelium of
the skin, and therefore indicates the site of the embryonic anal
membrane (p. 380).

Blood-supply of the Rectum and Anal Canal. — (i) The superior
hfzmorrhoidal artery (p. 341) descends in the root of the pelvic meso-colon
and divides into right and left branches, which run downwards on the muscular
coat of the rectum. They give off numerous branches, which pierce the
muscular coat and supply the mucous membrane of the rectum and the upper
part of the anal canal, anastomosing freely with one another and with the
inferior and middle hsemorrhoidal arteries.

(2) The middle h&morrhoidal arteries arise from the hypogastric arteries
and are mainly distributed to the muscular coat of the 'rectum. As they
approach the gut they are embedded in cellular tissue, which offers some
resistance when the surgeon endeavours to drag down the rectum in the
operation of excision (p. 382). This cellular tissue is termed by Ball the
lateral ligament of the rectum.

(3) The inferior hcemorrhoidal arteries arise, on each side, from the internal
pudendal in Alcock's canal (p. 373) and run downwards and medially across
the ischio-rectal fossae to reach the sides of the anal canal. They are dis-
tributed to the muscular wall of the anal canal and to the lower part of its
mucous coat.

(4) The middle sacral artery arises from the abdominal aorta near its
termination and runs downwards in the median plane on the anterior surface
of the sacrum. It supplies a few twigs to the muscular coat of the rectum.

Veins of the Rectum and Anal Canal. — The internal hcemorrkoidal
plexus lies in the submucous tissue of the anal canal, and by its means the
superior, middle, and inferior hsemorrhoidal veins communicate with one
another.

The superior hezmorrhoidal veins arise from the upper end of the plexus
and pass upwards in the submucous coat of the rectum. About the middle
of the rectum they pierce the muscular coat and unite to form a common
trunk, which ascends in the pelvic mesocolon and ultimately becomes the
inferior mesenteric vein (p. 321).

The middle hcemorrhoidal veins also arise in the internal haemorrhoidal

THE PELVIS 371

plexus and pierce the muscular coat of the anal canal. They run backwards
on the upper surface of the levator ani and join the hypogastric (internal
iliac) vein.

The inferior hcemorrhoidal veins join the internal pudendal vein.

The anal veins are arranged radially around the margin of
the. anus. They communicate with the internal haemorrhoidal
plexus and also with the inferior haemorrhoidal veins. Excessive
straining during the passage of large scybala may lead to rupture
of one of the anal veins, and the extravasated blood gives rise
to a small swelling at the muco-cutaneous junction, which is
termed an external h&morrhoid.

Varicosity of the veins of the internal haemorrhoidal plexus
constitutes the condition known as internal hemorrhoids. This
may be brought about by portal obstruction, whether hepatic
or cardiac in origin, since the portal and systemic circulations
communicate in the internal hsemorrhoidal plexus (p. 311).
Further, the course taken by the superior hsemorrhoidal veins
exposes them to marked obstruction during contraction of the
muscular coat of the rectum and the downward passage of
faeces. This obstruction, together with the absence of venous
valves, acts as a predisposing cause of the condition. Internal
haemorrhoids may become prolapsed through the anus with
each evacuation of the bowels or they may even protrude in
the erect posture. Their constriction by the external sphincter
gives rise to an acute attack of " piles," and may lead to areas
of sloughing or actual gangrene.

Bleeding from internal haemorrhoids is venous in nature and
irregular in occurrence. On the other hand, bleeding from a
malignant tumour of the rectum is arterial in nature and occurs
with each act of defaecation.

In the operation for internal haemorrhoids, the clamps or
forceps should be applied parallel to the course of the vessels,
i.e. in the long axis of the bowel, and special care should be
taken to make sure that the vessels at the base of the pile are
secured. If this is not done, considerable haemorrhage may
occur into the rectum with no outward sign until an enormous
blood-clot is passed or the condition of the pulseattraets attention.

The Nerve -Supply of the Rectum and Anal Canal is
mainly derived from S. 2, 3, and 4, through the sympathetic
system. The nerves which supply the internal trigone of
the bladder and the sphincter vesicae internus are derived
from the same source (p. 362). It is not surprising to find

372 THE ABDOMEN AND PELVIS

that interference with the rectum or anal canal produces
reflex results in the bladder. For example, retention of urine,
due to spasm of the sphincter vesicse internus, may follow
operations on the anus or rectum. A similar result may be
brought about by irritation of the cutaneous nerves of the
perineum (S. 2, 3, and 4), e.g. following a long cycle ride.

Cutaneous branches are supplied by S. 2 and 3 to the back
of the thigh and leg (p. 418), and may be the site of referred
pain in irritative or inflammatory conditions of the rectum or
pelvic colon.

The lower part of the anal canal, which is ectodermal in
origin (p. 381), receives its nerve -supply from the inferior
haemorrhoidal nerve.

The Lymph Vessels of the rectum and anal canal, above
the pectinate line, drain into lymph glands which lie on the
posterior surface of the rectum and their efferents ascend along
the superior hsemorrhoidal artery to end in the sacral and
lumbar lymph glands.

From the lower part of the anal canal, the lymph vessels
pass to the subinguinal lymph glands (p. 400). They reach their
destination by two paths ; some run antero-laterally across
the urogenital triangle, and the others run postero-laterally
round the lateral aspect of the thigh at about the level of the
greater trochanter. From the inguinal group, efferents pass
through the femoral (crural) ring to join the external iliac lymph
glands.

Examination of the Rectum and Anal Canal. — After
passing through the anus, the finger is at once grasped by the
external sphincter, but may be gently advanced upwards and
forwards for about one and a half inches, until it slips past
the internal sphincter and enters the rectal ampulla. If the
anus is found to be tightly contracted and very tender, anal
fissure may be suspected, and further examination should be
conducted under an anaesthetic.

Through the lowest part of the anterior wall of the rectal
ampulla the bulbo-urethral glands (of Cowper) can be felt, when
they are inflamed and enlarged. At a slightly higher level,
the posterior surface of the prostate can be examined. The
seminal vesicles, lying on the posterior surface of the bladder,
can be recognised, when diseased, as nodular projections im-
mediately above the prostate. About three inches from the
anus, which is the average limit of reach, the finger-tip is in

THE PERINEUM 373

contact with the rectal wall just below the line of peritoneal
reflection.

If the finger is rotated laterally, the medial aspect of the
pelvic wall may be examined, and, posterp-laterally, the hypo-
gastric (internal iliac) lymph glands can be made out when
they are enlarged.

With the pulp of the finger directed backwards, the lowest
plica transversal-is recti (rectal valve) may be felt, and enlarged
lymph glands on the anterior surface of the sacrum can be
recognised by pressing them against the bone. When the
patient is told to strain, the part of the bowel which lies just
out of reach in the passive condition can be " threaded " on
the finger and examined.

In the " ballooned " condition of the rectum, the walls of
the gut cannot be made out after the finger has passed through
the internal sphincter.

In the female, the os uteri can be palpated through the
anterior wall of the rectum, and the uterus itself may be felt
when retroflexed.

THE PERINEUM.

The Ischio-Rectal Fossa lies between the lower part of
the obturator internus and the levator ani. Posteriorly, it is
limited by the glutseus maximus and the sacro-tuberous ligament;
anteriorly, it extends forwards to the urogenital diaphragm.
Above, it is shut off from the pelvis by the attachment of the
levator ani to the parietal pelvic fascia (Fig. 114). The sloping
medial wall of the fossa is formed by the levator ani as it clothes
the anal canal and the lower part of the rectum.

After leaving the gluteal region (p. 417), the internal pudendal
vessels enter Alcock's canal, which lies in the fascia on the
lateral wall of the ischio-rectal fossa. They give off the inferior
hsemorrhoidal vessels, which pass downwards and medially
across the fossa to supply the anal canal. The vessels are
accompanied by the inferior hsemorrhoidal nerve, which arises
from the pudendal and terminates in the external sphincter.

Ischio - rectal abscesses originating in connection with
some small ulcer, laceration of the rectal sinuses, etc., may
rupture through the skin and give rise to an external sinus ; or

24 a

374

THE ABDOMEN AND PELVIS

they may rupture into the anal canal,, in which case an internal
sinus is formed. The orifice of an internal sinus is generally
found at the pectinate line (p. 370), i.e. the track of the sinus
lies below the level of the levator ani and longitudinal muscular
coat of the gut. An ischio-rectal abscess may rupture in both
directions and so give rise to a complete fistula. As the whole
fistula lies below the internal sphincter, it is only necessary to
divide the external sphincter, the movements of which tend to
keep the fistula open. This should be carried out radially from
the anal margin, i.e. at right angles to its fibres, and in one place

Bladder

Recto-vesi
fascia

Anal canal

Obturator internus

Levator ani, clothed on

medial side by rectal

fascia, and on lateral side

by lower fascia of pelvic

diaphragm

Alcock's canal, con- „--"
taining pudendal
vessels and nerve

FiG. 114. — Diagram of the Endo-pelvic Fascia. The pelvis is divided in a
frontal plane and the pelvic fascia is represented in red.

only, otherwise the muscle may fail to unite. In the examination
of a case of fistula in ano, it is advisable to pass a probe into
the fistula before inserting the finger into the anal canal, as
this process may induce spasm of the external sphincter and
so make the passage of a probe a matter of greater difficulty.
Sometimes the mucous membrane is undermined for some
distance above the internal opening of the fistula, and the
point of the probe may be felt separated from the finger by
the mucous coat alone.

Abscesses arising above the levator ani, either in connection
with the pelvic organs or diseased bone, sometimes pierce the
muscle and enter the ischio-rectal fossa from above.

The Pudendal Nerve arises from the sacral plexus (S. 2, 3,

THE PERINEUM

375

and 4); and accompanies the internal pudenda! vessels through
the greater sciatic foramen (p. 417). It then passes downwards
on the dorsal surface of the sacro-spinous (small sacro-sciatic)

Parietal

peritoneum

Fascia

transversalis

Fascia of Scarp

ascia of Camper

Bladder I H
II
If
l|

Pubo-prostatic /'
ligament

Frost

Deep dorsal
vein of penis

Urethra

!ulb of corpus

cavernosum

urethrse

Bulbo-caver-

nosus muscle

Prepuce

Fossa
navicularis

Parietal pelvic
fascia

Sacro-genital

fold

Ductus defereri

Recto-vesical

fascia

Ejaculatory

duct

Upper fascia of

urogenital

diaphragm

Lower fascia ol

urogenital

diaphragm

Anal canal

Fascia of Colles

FIG. 115. — Diagram of Median Section through Male Pelvis, showing the
arrangement of the Peritoneum, the Endopelvic Fascia and the Fascia
of Colles.

ligament and enters the posterior part of the ischio-rectal fossa
through the lesser sciatic foramen. In Alcock's canal, it gives
off the inferior hczmorrhoidal and divides into the perineal nerve
and the dorsal nerve of the penis.

24 6

376 THE ABDOMEN AND PELVIS

The Urogenital Triangle extends from the pubic
symphysis to the central point of the perineum, which lies
half an inch anterior to the anus, and it is limited laterally by
the pubic arch.

The superficial fascia over this region consists of two strata.
The first is a fatty layer, continuous with the general fatty
covering of the body. The second, the deeper layer, is denser
and more membranous in character. Above, it is continuous
with the fascia of Scarpa (p. 240), which is continued downwards
from the abdomen on each side to be attached to the fascia lata
of the thigh just distal to the inguinal (Poupart's) ligament.
Between the two pubic tubercles, the fascia of Scarpa is carried
down over the urogenital triangle, where it is termed the fascia
of Colles. The latter encloses the penis, as in the finger of a
glove, clothes the scrotum, and finally blends with the base of
the urogenital diaphragm. Laterally, the fascia of Colles is
attached to the fascia lata of the thigh from the pubic tubercle
downwards and medially to the border of the pubic arch, and
then along the latter to the tuber ischii.

The Superficial Perineal Pouch is a space which is bounded
in front by the fascia of Colles, and behind by the urogenital
diaphragm. It is closed inferiorly by the union of its two walls
and laterally by their attachments to the pubic arch . Superiorly,
however, it communicates freely with the cellular interval
between the fascia of Scarpa and the anterior wall of the rectus
sheath. The superficial perineal pouch contains the structures
which form the root of the penis and the muscles which cover
them (p. 377). It also contains the whole of the cavernous
(spongy) portion of the urethra, and rupture of this portion of
the urethra, whether from trauma or following stricture, leads
to extravasation of urine into the pouch. This first affects the
lowest part of the pouch, viz. between the neck of the scrotum
and the base of the urogenital diaphragm, and then passes
forwards and distends the scrotum (Fig. 115). The loose cellular
tissue of the penis next becomes infiltrated, and the " ram's
horn penis " is produced. Lastly, the extra vasated urine
passes upwards on to the anterior abdominal wall spreading
laterally behind the fascia of Scarpa, and the attachment of the
latter to the fascia lata prevents its downward spread into the
thigh.

The root of the penis consists of the bulb and the two crura. The
bulb is placed in the median plane and is closely attached to the inferior fascia

THE PERINEUM

377

of the urogenital diaphragm (anterior layer of triangular ligament). It is
traversed by the urethra and its surface is completely covered by the bulbo-
cavernosus (ejaculator urincv) muscle, which serves to eject the last drops of
urine or semen. The cms penis is firmly attached to the margin of the pubic
arch and is covered by the ischio-cavernosus (erector, penis} muscle. The two
crura converge anteriorly and lie side by side on the dorsum of the body of the
penis, where they are termed the corpora cavernosa. The bulb is continued
forwards as the corpus cavernosum urethrae (corpus spongiosum), which forms
the ventral part of the body of the penis.

The superficial transverse perineal muscle lies in the most posterior part
of the superficial perineal pouch (Fig. 115). It cannot be exposed without
incising the fascia of Colles, and it forms an important landmark in perineal
surgery.

FIG. 116. — The Segmental Supply of the Skin in the Perineum.

Superficial Perineal Nerves. — (i) The posterior scrotal nerves, two
in number on each side, arise from the pudendal (S. 2, 3, and 4) and supply
the skin over the urogenital triangle and the scrotum.

(2) The long perineal branch (long pudendal) of the posterior cutaneous
nerve of the thigh (S. i, 2, and 3) assists in the supply of the same areas.

(3) The dorsal nerve of the penis arises from the pudendal (S. 2, 3, and 4)
and runs along the dorsum of the penis. It ends by supplying the glans.

(4) The perforating cutaneous nerve (S. 2 and 3) supplies the skin in the
neighbourhood of the coccyx.

(5) The perineal branch of S. 4 supplies the skin round the anus.

(6) The inferior htzmorrhoidal nerve (p. 375) helps the perineal branch of
S. 4 to supply the skin round the anus.

The superficial nerves of the perineum all spring from the
anterior rami of the sacral nerves. Pain may be referred to

378 THE ABDOMEN AND PELVIS

this region in irritative conditions of those viscera which receive
their nerve-supply from the same source, e.g. bladder, rectum,
seminal vesicles, etc. It has already been pointed out (p. 372)
that irritation of the perineal nerves may reflexly affect the
viscera mentioned.

The Urogenital Diaphragm separates the perineum from
the pelvis anteriorly. It is formed by the sphincter urethrse
and the deep transverse perineal muscles, which are enclosed
between two layers of fascia. The two fascial layers blend
with one another and with the fascia of Colles inferiorly, and
they are attached on each side to the margin of the pubic arch.
The superior fascia (deep layer of triangular ligament) consists
of parietal pelvic fascia (p. 356), while the inferior fascia
(superficial layer of triangular ligament) forms the postero-
superior wall of the superficial perineal pouch. The space
between the two layers is completely closed and is termed the
deep perineal pouch. It contains (i) the membranous portion
of the urethra and its sphincter muscle, (2) the deep transverse
perineal muscle and the bulbo-urethral glands (of Cowper),
(3) the artery to the bulb, and (4) the internal pudendal vessels
and the dorsal nerve of the penis.

Rupture of the membranous portion of the urethra leads to
extravasation of urine into the deep perineal pouch, and the
extravasated urine can only find an exit from this space by
bursting through either the anterior or the posterior wall of the
pouch. In the first case, the urine then passes into the superficial
perineal pouch, and its subsequent course is described on p. 376.
In the second case it enters the interval which lies immediately
below the pubo-prostatic ligaments (Fig. 115); and bursts
through between them, gaining the space of Retzius. It then
ascends the anterior abdominal wall between the trans versalis
fascia and the parietal peritoneum. Extravasated urine will
also be found in this situation after rupture of the prostatic
urethra, and after extra-peritoneal rupture of the bladder.

The Internal Pudendal Artery, on leaving Alcock's canal,
pierces the base of the urogenital diaphragm and runs forwards
in the lateral part of the deep perineal pouch. It pierces the
inferior fascia of the diaphragm under cover of the cms penis
and ends by dividing into the deep artery of the penis (artery to
the corpus cavernosum} and the dorsal artery of the penis. Before
it enters the pouch, it gives off superficial branches, which ramify
in the superficial pouch and supply the muscles and skin.

THE PERINEUM 379

In the deep perineal pouch, the internal pudendal gives off
the important artery to the bulb, which runs medially and pierces
the inferior fascia of the urogenital diaphragm near the middle
line in order to reach the bulb. It usually lies three-quarters
of an inch from the base of the diaphragm. In the old operation
of lateral lithotomy, the point of the knife was entered i£ inches
in front of the anus and just to the left of the middle line, and
was carried backwards and laterally through the left ischio-
rectal fossa towards a point midway between the anus and the
tuber ischii. In this way the whole of the incision lay behind
the artery to the bulb. The posterior fibres of the bulbo-
cavernosus and the superficial transverse perineal muscle and
artery were divided in the anterior part of the wound, and the
urethra was reached by incising the inferior fascia of the
urogenital diaphragm and the sphincter urethrae. The point
of the knife was then carried along the grooved staff into the
bladder, cutting through the left lobe of the prostate and its
sheath.

Perineal Prostatectomy. — In this operation the prostate
is approached from below and behind.

An incision, convex forwards, is made between the ischial
tuberosities, and the skin and fasciae are reflected until the
superficial transverse perineal muscle is exposed and the base
of the urogenital diaphragm defined. The recto-urethralis
muscle is then exposed and divided transversely. The fingers
may now be inserted into the cellular interval between the
prostate and the rectum and the two viscera can readily be
separated. The urethra is then incised at the apex of the
prostate, by cutting on a staff with a median groove. The
incision should not be more than a third of an inch long and
should not injure the sphincter urethrae. The staff may then
be withdrawn and Young's prostatic tractor is passed into the
bladder through the incision in the urethra. By its means,
the prostate is drawn downwards and backwards till it appears
in the wound. Its sheath is then incised on each side, and the
two halves of the prostate are removed separately.

This operation was introduced by Young, of Baltimore, with
a view to preserving the ejaculatory ducts and the prostatic
urethra. Further, the mucous coat of the bladder is not
interfered with, and perineal drainage is obtained through the
urethral wound.

Development of the Genito-Urinary Organs.— The part of the gut

380 THE ABDOMEN AND PELVIS

which lies caudal to the origin of the allantois (Fig. 89) is known as the
cloaca, and it becomes subdivided by a frontal (coronal) mesodermal septum
into ventral and dorsal portions. The ventral portion is differentiated into
a dilated upper part which forms the bladder, and a narrower lower part
which is termed the urogenital sinus, and the latter receives the openings of
the Wolffian ducts. The dorsal portion of the cloaca forms the rectum, and,
probably, other parts of the large intestine.

Prior to this subdivision, the ectoderm and entoderm in the ventral wall
of the cloaca are in direct apposition — no mesoderm intervening — over an
area which is termed the doacal membrane. In the adult, this corresponds
roughly to the area between the symphysis pubis and the tip of the coccyx.
The septum which subdivides the cloaca reaches the cloacal membrane and
divides it into two parts, which are known as the urogenital and anal mem-
branes, respectively. About the eighth week of foetal life the urogenital
membrane breaks down, and the bladder thus acquires an opening on the
surface of the perineum.

At the cephalic end of the cloacal membrane, the ectoderm becomes
heaped up to form an elevation, which, in the male, becomes the phallus.
Before the urogenital membrane breaks down, the urogenital sinus extends
forwards, so that after the rupture it opens not only on the perineum but
also on the caudal aspect of the phallus. As the latter rapidly increases in
the male to form the penis, the opening extends forwards and, pari passu,
becomes closed posteriorly, so that the urethra, which is thus derived from
entoderm, ultimately opens on the ventral surface of the penis at the base
of the glans. At a later stage, the urethra extends into the glans and the
orifice migrates forwards to the apex. It is still doubtful whether the terminal
part of the urethra is ectodermal or entodermal in origin.

In the female, the genital eminence forms the clitoris, which is homologous
with the glans penis.

Congenital Anomalies. — (a) Hypospadias. The simplest variety of
hypospadias is due to persistence of the orifice at the base of the glans ; the
highest degree is found where the phallus remains diminutive, and the
membranous urethra opens on the surface of the perineum. Intermediate
degrees of this anomaly may occur.

(b) In Epispadias, the urethra opens on the dorsal surface of the penis
near its attachment to the anterior abdominal wall. This abnormality is
due to rupture of the urogenital membrane at a point cephalic to the genital
eminence instead of caudal to it.

(c) In some cases, the urogenital membrane is more extensive than
normal, and rupture cephalic to the genital eminence not only gives rise to
epispadias but the cleft is continued forwards and complete extroversion of the
bladder is produced. In this condition, the lower part of the anterior
abdominal wall is deficient and the two pubic bones fail to meet one another
in the middle line, so that the symphysis is absent. The posterior wall of the
bladder is exposed on the surface below the umbilicus and forms a somewhat
triangular red area, on which the ureters and genital ducts open. The
margins of the mucous membrane are continuous with the skin of the
abdominal wall. Complete extroversion of the bladder is always accompanied
by epispadias.

The Scrotum. — Two lateral swellings, which are termed the labio-scrotal
folds, lie one on each side of the genital eminence. As they grow tailwards.
they pass lateral to the perineal orifice of the urogenital sinus, and they blend
with a central swelling which occupies the middle line in front of the anus.
In the male, the scrotum is formed by this central swelling and the caudal
ends of the labio-scrotal folds. In the female, the labio-scrotal folds persist
in their entirety and constitute the labia majora.

THE PERINEUM 381

The Urachus is a fibrous cord which extends in the adult from the apex
of the bladder to the umbilicus. It lies between the fascia transversalis
and the parietal peritoneum and represents the embryonic connection between
the cloaca and the allantois, after the formation of the umbilical cord (p. 287).
This connection normally disappears quite early, but it may persist and give
rise to cysts or umbilical urinary fistultz.

Congenital Anomalies of the Rectum and Anal Canal.—

The anal membrane (p. 380) lies at the bottom of a surface
depression, which is termed the proctodceum. During the third
month; the anal membrane breaks down and the alimentary
canal opens on the perineum. The upper half of the anal canal
is entodermal in origin, but its lower half is derived from the
ectoderm lining the proctodaeum.

Should the anal membrane fail to break down, the condition
of imperforale anus results. In some cases, the condition is
very simple, and a small incision through the anal depression
at once opens the lower end of the rectum. In other cases,
however, the rectum ends blindly two or three inches or more
from the surface. It is probable that, in these cases, the
mesoderm, which separates the urogenital and anal membranes,
has invaded the latter and, by rapid proliferation, has widely
separated its two layers from one another.

Connections of the rectum with the bladder or prostatic
urethra are due to failure of the mesodermic septum to effect
a complete subdivision of the cloaca into ventral, urinary, and
dorsal, intestinal segments.

In Excision of the Rectum, the method adopted depends
entirely on the extent of the disease. The operation which is
described here is chosen when a permanent colostomy has been
previously established ; and it is carried out with the patient
in the exaggerated lithotomy position. In order to prevent
any leakage during the subsequent manipulations, the anus is
stitched up and an incision is made through the skin and fascia
around it. This is continued backwards in the median plane
up over the coccyx and lower part of the sacrum, if considered
necessary. The posterior part of the incision is deepened and
the median raphe of the levatores ani is split as far back as the
coccyx. In the removal of the coccyx, which constitutes the
next step, the glutseus maximus must be separated from its
dorsal surface and the attachments of the coccygeus and the
sacro-spinous and sacro-tuberous ligaments (small and great
sacro-sciatic ligaments) to its sides require to be cut through.
The bone may then be disarticulated from the sacrum or, if

382 THE ABDOMEN AND PELVIS

necessary, the lower part of the sacrum may be removed, but
the bone must be divided below the third pair of sacral foramina,
otherwise incontinence of urine and faces will result.

The middle sacral artery (p. 370) is ligatured, and then, by
dissection with the fingers, the levator ani is separated from
the rectum on each side and the visceral layer of the pelvic fascia
is torn through as it passes from the upper surface of the muscle
on to the gut. In the region of the rectal ampulla, the fingers
may be gradually insinuated round the bowel, passing between
it and the base of the bladder and prostate. One blade of a
pair of scissors is next inserted above the levator ani at the
point where the median incision meets the incision round the
anus, and, with the other blade in the circular incision, the
wound is deepened around the anal canal. In this process
the levatores ani are divided until their anterior free borders are
reached on the antero-lateral aspect of the rectum. Anteriorly,
the recto-urethralis and the attachment of the external sphincter
to the central point of the perineum require to be cut through,
and the former must be divided as close to the rectum as possible,
in order to avoid injuring the membranous part of the urethra.

As a result of this step, the anal canal and the lower two
inches of the rectum can be dragged downwards and a further
inch can be freed, with the fingers and with scissors, from its
anterior peritoneal covering.

Some difficulty will be experienced in dragging down more
of the rectum, as it is anchored in place by the cellular tissue
in which the middle hsemorrhoidal vessels are embedded. These
" lateral ligaments " having been clamped and divided, the
bowel is only held by its peritoneal covering. The peritoneum is
incised transversely, close to the rectum, along the recto-vesical
line of reflexion. As the bowel is gradually pulled down, the
peritoneum is incised along each side and the branches of the
superior hsemorrhoidal artery are secured as they are met with.

After the bowel has been mobilised for some distance above
the diseased area, its peritoneal surface is stitched to the cut
recto-vesical peritoneum. Just below the sutured area, the
bowel is ligated and cut through, and it can then be lifted away.
The proximal cut end may be surrounded with a purse-string
suture and invaginated, the usual procedure in closure of the
large intestine.

This operation produces less shock than some of the more
extensive operations which provide the patient with a new

THE PERINEUM 383

rectum and anal canal. In such operations the pelvic colon is
mobilised (p. 343) so as to permit of its being stitched to the
anus, and, at the same time, the external sphincter is preserved.

The Male Urethra is about nine inches long from its
internal orifice at the neck of the bladder to its external orifice
on the glans penis. It may be conveniently divided into a
posterior, fixed portion, consisting of the prostatic and
membranous parts and the part within the bulb and an anterior,
movable portion, situated in the corpus cavernosum urethrae
(corpus spongiosum).

In the flaccid condition of the penis, the urethra follows an
c/) -shaped bend, but when the penis is drawn upwards towards
the abdomen, its course becomes J-shaped. By this alteration,
the surgeon is enabled to pass a rigid instrument with a single
curve along the urethra into the bladder.

The Prostatic Part of the Urethra is about ij inches
in length and is embedded in the prostate, somewhat nearer
to the anterior than to the posterior surface. It is the widest
and also the most dilatable part of the urethra. About half
an inch wide at its mid-point, it narrows slightly at each end,
but it may be dilated so as to permit the passage of the finger
into the bladder. On account of this distensibility, the removal
of stones from the bladder was at one time carried out through
the prostatic urethra.

A longitudinal ridge, termed the urethral crest, occupies the
floor of the prostatic urethra in nearly its whole extent.
Longitudinal grooves lie one on each side of the crest ; they are
termed the prostatic sinuses and receive the prostatic ducts.
It is in these ducts that chronic gonorrhceal inflammation may
linger in posterior urethritis. Near the lower end of the crest,
a small median opening leads into a blind diverticulum, which
passes upwards and backwards below the middle lobe of the
prostate. This is termed the prostatic utricle (sinus pocularis),
and near its orifice, which is sometimes large enough to entangle
the point of a fine instrument, the prostatic urethra receives
the openings of the ejaculatory ducts. Gonorrhceal infection
of the posterior urethra may spread into the ejaculatory ducts
and involve the seminal vesicles, or it may spread along the
ductus (vas) deferens and give rise to epididymitis.

The Membranous Part of the Urethra is narrower than
any other part of the urethra except the external orifice. It
is only three-quarters of an inch long, and it lies between the

384 THE ABDOMEN AND PELVIS

two fascial layers of the urogenital diaphragm, surrounded by
its sphincter muscle (p. 378).

The bulbo-urethral glands (of Cowper) lie infero-lateral to the
membranous urethra, and their ducts pierce the inferior fascia
of the diaphragm (p. 378) to open into the cavernous urethra.
These glands are sometimes involved in gonorrhceal inflammation
of the anterior urethra, and they may give rise to abscesses,
which can be recognised on rectal examination. The pus
should be evacuated through the perineum.

The Cavernous (Spongy) Part of the Urethra is about
six or seven inches long and is enclosed in the bulb, the corpus
cavernosum (spongiosum) urethras and the glans penis. The
external orifice on the glans is the narrowest part of the canal,
and it may require to be incised to permit the passage of bougies,
which will then readily pass along the remainder of the urethra.
Enlargement of the external urethral orifice should be carried
out by cutting from within outwards towards the fraenulum.

Immediately within the external orifice, the urethra widens
out to form the fossa navicularis, which involves the roof rather
than the floor of the canal. Near the posterior end of the fossa
a fold of mucous membrane projects downwards from the roof
and may temporarily hinder the passage of an instrument, but,
by directing the point of the instrument towards the floor of
the urethra, this slight obstruction is easily avoided.

Behind the fossa navicularis, the urethra becomes narrower,
but it again enlarges when it reaches the bulb. This is the
most dependent part of the fixed urethra, and, on this account,
is the commonest site of chronic gonorrhceal inflammation, and,
consequently, of organic stricture.

Stricture may occur at any point in the cavernous urethra.
When more than one is present, the first should be dilated to
full size before the next is dealt with. If this is not done, it
may be impossible to determine whether a bougie is obstructed
by a deep stricture or whether its shoulders are caught in the
one first encountered.

In negotiating a difficult stricture in the bulb, great care
and gentleness must be exercised lest a false passage be made.
The surgeon stands on the left side of the patient and manipulates
the handle of the instrument with his right hand. This leaves
his left hand free, and the left forefinger, if inserted into the
rectum, may be of great assistance in guiding the point of the
instrument, thus preventing the formation of a false passage.

THE PERINEUM 385

The passage of a rigid instrument. No. 8 or 9, along a healthy
urethra into the bladder presents no difficulty, if its point is
kept in contact with the roof of the urethra after the fossa
navicularis has been traversed. When a small instrument is
used, some difficulty may be experienced in passing from the
bulb into the membranous urethra as, unless the point is kept
along the roof of the canal, it impinges against the urogenital
diaphragm just below the urethral opening. In these cases,
the instrument should be withdrawn for a short distance and
then the handle should be depressed so that the point may rise
towards the orifice in the diaphragm.

The Body of the Penis consists of the two corpora cavernosa,
which lie side by side on the dorsum, and the corpus cavernosum
urethra (c. spongiosum), which lies in the groove separating the
two corpora cavernosa ventrally. At its termination, the
corpus cavernosum urethrae expands into a conical enlargement,
termed the glans penis, which projects dorsally and laterally,
so as to cover the extremities of the corpora cavernosa.

The component parts of the penis contain numerous venous
spaces, in which the blood may be retarded by the contraction
of the ischio-cavernosi and the bulbo - cavernosus (p. 377),
leading to enlargement of the organ. In conditions of
gonorrhceal inflammation, the spaces in the corpus cavernosum
urethrae, being already rilled with serous exudate, fail to distend,
when the corpora cavernosa are undergoing distension. As a
result, the penile erection is not straight but is curved, owing
to the inelastic condition of the corpus cavernosum urethrae.
This constitutes the condition which is known as chordee.

The skin of the penis is very thin, and is freely movable over
the body of the organ. At the extremity of the penis it is
folded back to form a hoodlike covering for the glans. This is
termed the prepuce • its deep surface is lined by modified skin,
which is reflected on to the glans (i) at its base, the corona
glandis, and (2) on its ventral aspect, where it forms the frenulum.
The modified skin covering the glans is firmly adherent, and
contains sebaceous glands, which secrete the smegma. The
latter collects in the region of the corona glandis, and may
sometimes form concretions.

In the condition of Phimosis there is a long narrow prepuce,
which cannot be drawn back off the glans. Adhesions between
the deep surface of the prepuce and the skin surface of the glans
may give rise, reflexly, to urinary disturbances. The whole

25

386 THE ABDOMEN AND PELVIS

condition may be relieved by circumcision. In this operation
the prepuce is drawn forwards over the apex of glans and
removed. When adhesions are present the prepuce itself
cannot be drawn forwards,, and the skin which is drawn forwards
is derived from the body of the penis. If this portion is cut
away, the cut proximal end at once retracts, and the penis may
be almost completely denuded, while the prepuce is left intact,
i.e. a circular strip of skin is removed from the body of the
penis.

In the normal case, when the prepuce is cut away, the
external covering of skin retracts, but the deep layer remains in
contact with the glans. This layer may be slit along the dorsal
surface with scissors, but care must be taken not to insert the
point of the lower blade into the external urethral orifice.
Thereafter, each portion of the deep layer of the prepuce may
be stripped from the glans with the ringers, and a layer of smegma
is usually disclosed around the corona.

On the dorsal surface tributaries of the dorsal vein and
branches of the dorsal arteries of the penis will require to be
tied. In addition, if the frenulum is divided, the little artery
which runs in it must be secured ; it is a branch of one of the
arteries to the bulb. The cut edge of the skin is then stitched
to the deep layer of the prepuce.

The condition of Paraphimosis results when a tight prepuce
is drawn backwards off the glans and allowed to remain as a
constricting band above the corona. The glans becomes
engorged and cedematous, and actual gangrene may ensue,
unless the prepuce is replaced. This may be carried out by
exercising steady pressure on the glans with the thumbs while
traction on the prepuce is maintained by the encircling fingers.

The Superficial Dorsal Vein of the Penis arises on the
dorsum just behind the glans by the union of small tributaries
from the glans and prepuce. It runs backwards in the middle
line immediately under the skin of the dorsum, and ends by
dividing into right and left branches, which join the internal
pudendal veins.

The Deep Dorsal Vein of the Penis lies on a deeper plane.
It passes into the pelvis between the symphysis pubis and the
upper edge of the urogenital diaphragm (Fig. 115), and finally
it divides into right and left branches, which join the pudendal
(prostatic) plexus of veins.

Each Dorsal Artery of the Penis arises from the internal

THE FEMALE PELVIS 387

pudendal (p. 378), and runs forwards on the dorsal surface of
the corpus cavernosum ; which it supplies.

The Dorsal Nerve of the Penis (S. 2, 3, 4) is derived from
the pudendal (p. 374). It lies lateral to the dorsal artery and
supplies branches to the skin of the penis, prepuce, and glans.

The superficial and the deep lymph vessels of the penis end,
respectively, in the superficial and the deep subinguinal lymph
glands (p. 400).

THE FEMALE PELVIS.

The differences between the male and female generative
organs necessitate a somewhat different arrangement of the
Pelvic Peritoneum in the female.

On leaving the anterior surface of the rectum, the peritoneum
passes forwards, forming the floor of the recto-uterine fossa,
and reaches the posterior aspect of the vagina, which it clothes
in its upper fifth. From the posterior surface of the vagina
the peritoneum passes upwards on the posterior surface of the
uterus to the fundus. It then descends over the anterior surface
of the uterus, but at about one inch above the vagina it passes
forwards on to the superior surface of the bladder, forming the
floor of the utero-vesical fossa (Fig. 117).

The Broad Ligament of the Uterus is a somewhat
triangular sheet of peritoneum which extends laterally from
the lateral border of the uterus to the pelvic wall. It consists
of two layers which become continuous with one another at the
upper free border of the ligament, where they enclose the
uterine (Fallopian) tube. Infero-laterally the two layers separate
to cover the floor and side-walls of the pelvis. The plane of the
broad ligament depends partly on the position of the uterus.
Normally its anterior surface is directed downwards and slightly
forwards.

Certain parts of the broad ligament receive special names,
(i) The mesosalpinx is the part which lies immediately below
the uterine tube. (2) The mesovarium is the fold which passes
from the posterior layer of the broad ligament to enclose the
ovary. It contains the ovarian vessels, nerves, and lymphatics.
(3) The suspensory ligament of the ovary is that part of the broad
ligament which extends between the upper pole of the ovary
and the pelvic wall. Its lateral attachment is placed a little

388

THE ABDOMEN AND PELVIS

below and behind the abdominal inguinal ring (p. 264). The
ovarian vessels, etc., traverse the suspensory ligament on their
way to the mesovarium.

The Vagina, which is about three inches long, is directed
upwards and backwards and lies in the interval between the

Ureter
Obturator fossa • Ovary

Ovarian vessels
Obturator fossa ,'

Folds produced by nerve-cords
Pararectal fossa

Paravesical fossa
Round ligament

Obliterated umbilical

artery

[nf. epigastric artery ;'

Recto-uterine pouch of Douglas

Utero-sacral fold

FIG. 117. — Median Section through the Female Pelvis to show the disposition
of the Peritoneum. (Dixon and Birmingham.)

urethra and bladder, in front, and the anal canal and rectum,
behind. Its upper half lies above the level of the muscular
floor of the pelvis, and is surrounded by the visceral pelvic fascia.
Its lower half is embraced by the levatores ani, and at a lower
level, by the bulbs of the vestibule (p. 397), and the bulbo-
cavernosus (sphincter vaginse) muscle.

Superiorly, the vagina is attached around the cervix uteri,
which projects obliquely downwards and backwards into the

THE FEMALE PELVIS 389

canal. Around the cervix there is a shallow groove,, termed
ihefornix, which is deepest posteriorly.

Anteriorly, the lower part of the vagina is related to the
urethra. This area may undergo sloughing from continual
pressure during parturition, and a urethro-vaginal fistula may
result. Above this level, the vagina is related to the posterior
surface of the bladder, from which it is only separated by some
loose cellular tissue, as it lies entirely below the peritoneum
of the utero - vesical fossa. This arrangement is of great
importance to the surgeon, as it permits the bladder to be easily
separated from the cervix and vagina. It is through this area,
too, that malignant diseases of the cervix may spread to the
bladder.

Posteriorly, the vagina is related to the anal canal and rectum.
In its lower part it is separated from the anal canal by a fibro-
muscular mass which is termed the perineal body, and in its
upper fifth or more it is separated from the rectum by the lowest
part of the recto-uterine fossa and the viscera which it contains.

During parturition the posterior commissure (p. 397) may
give way, and the laceration may involve the skin and superficial
tissues of the perineum as far back as the anus. The posterior
wall of the vagina may also be involved, and occasionally the
levator ani, and the sphincter muscles of the anal canal are
affected. Incontinence of faeces only occurs when the internal
sphincter is torn through.

Following severe lacerations of the perineum which involve
the levator ani, the posterior vaginal wall may become prolapsed
through the vulva. This condition is usually accompanied
by a dilatation of the ampulla of the rectum, which pouches
forwards into the relaxed posterior vaginal wall, constituting
the condition known as a rectocele. A strain is thus placed on
the anterior wall of the vagina, and it in turn becomes prolapsed,
dragging the bladder with it to form a cystocele. Lastly, the
uterus itself descends, and a complete prolapse is the final stage.

In the operation of colporrhaphy, which is undertaken as a
remedial measure, oval areas of mucous membrane are removed
in the long axis of the anterior and posterior vaginal walls,
and the cut edges are then stitched together, thus narrowing
the vagina. In removing the mucous membrane of the anterior
vaginal wall and in stitching the cut edges together subse-
quently, great care must be taken to avoid injuring the
bladder and urethra.

25 a

390 THE ABDOMEN AND PELVIS

The Uterus is about three inches long and two inches
broad, and in shape resembles a pear, flattened antero-posteriorly.
At the upper ends of its lateral borders it receives the uterine
tubes, and the part of the organ which lies above this level is
termed thefundus. This part of the uterus is normally directed
forwards, and is completely covered by the peritoneum, which
is firmly adherent to it.

The body of the uterus lies below the fundus, and is separated
from the cervix by a slight constriction, termed the isthmus.
It is completely covered by peritoneum, which separates it,
anteriorly, from the superior surface of the bladder, and
posteiiorly, from the recto-uterine fossa. The body of the
uterus is the common site for fibroids, which may grow in the
subserous, muscular, or submucous coats.

The Cervix Uteri consists of a supra-vaginal and a vaginal
portion. The supra-vaginal portion is covered by peritoneum
on its posterior surface only, and this covering is very loosely
attached to the subjacent muscular coat. Anteriorly, the
supra-vaginal portion of the cervix is related to the bladder,
from which it is separated by some cellular tissue (p. 395).

The vaginal portion of the cervix projects downwards and
backwards into the antero-superior part of the vagina, and
receives a covering of squamous epithelium similar to that
which lines the vagina.

The cervix is traversed by the cervical canal, which
communicates with the~cavity of the uterus, above, through
the internal orifice and with the vagina, below, through the
external orifice. In nulliparse the external orifice of the uterus
is a circular depression, and, owing to the line of axis of the
cervix, is directed against the posterior vaginal wall. In
multipart the orifice becomes an irregularly transverse slit,
with somewhat everted anterior and posterior lips. The cervical
canal readily admits a sound 4 mm. in diameter. Should it
fail to do so, the condition of stenosis is present. Stenosis of
the cervix obstructs the menstrual flow, and gives rise to
dysmenorrhcea, which is most marked at the commencement
of the period.

Position of the Uterus. — The long axis of the uterus is
normally directed downwards and backwards, and this
arrangement -is described as anteversion of the organ. But in
addition to being anteverted, the normal uterus is bent forwards
on itself at the junction of the body with the cervix, and this

THE FEMALE PELVIS - 391

condition is termed anteflexion. The position of the uterus
varies somewhat with the condition of the bladder, but the
organ is prevented from becoming retroflexed and retroverted
by two ligaments on each side.

The round ligament is a fibro - muscular band, which is
attached to the uterus just below the uterine tube. It passes
laterally in the broad ligament, and projects slightly from its
anterior layer. On leaving the broad ligament, the round
ligament of the uterus enters the abdominal inguinal ring,
traverses the inguinal canal, and emerges from the subcutaneous
inguinal ring to be attached to the skin and subcutaneous tissue
of the labium majus (p. 396). Its relations at the abdominal
inguinal ring and in the canal are precisely the same as those
already described for the spermatic cord (p. 253).

The operation of shortening the round ligaments is sometimes
carried out in cases of retroflexion, but abdominal hysteropexy,
which consists in suturing the fundus to the anterior abdominal
wall, is more frequently performed.

The utero-sacral ligaments are fibro-muscular bands, which
extend from the posterior surface of the uterus just above the
cervix to the posterior wall of the pelvis lateral to the rectum.
They are extra-peritoneal, but produce peritoneal ridges, which
are known as the utero-sacral folds. These ligaments may
become shortened, following inflammatory conditions of the
perimetrium, and drag the lower part of the uterus backwards,
giving rise to acute ante-flexion.

In a retroflexed uterus, the cervix assumes a more vertical
position, and the external orifice of the uterus may be directed
straight down the vagina. In this position, the flexion at the
isthmus may be sufficiently pronounced to cause difficulty in
the evacuation of the menstrual discharge.

The pregnant uterus ascends from the pelvis into the
abdomen as it enlarges in size, but the retroverted gravid uterus
is prevented from doing so by the sacral promontory. The
enlargement of the viscus, therefore, causes increased intra-
pelvic pressure, and the urethra is pressed against the symphysis
pubis, causing first retention of urine, and later, the overflow
from a distended bladder. If the position of the uterus is
corrected, the pregnancy will follow a normal course.

The Uterine (Fallopian) Tube is attached to the uppermost
part of the lateral border of the uterus, and extends laterally
in the free upper margin of the broad ligament towards the

392 THE ABDOMEN AND PELVIS

pelvic wall, where it is closely related to the medial surface of
the ovary (Fig. 117).

The part of the tube which is embedded in the uterine wall
is known as the pars uterina. Lateral to it, the tube possesses
for a short distance well-marked longitudinal and circular
muscular coats. In this portion, which is termed the isthmus,
the lumen is very small. Lateral to the isthmus, the muscular
coat is not so strongly developed, but the mucous coat is very
much thicker. This part of the tube is known as the ampulla,
and its extremity widens out into the infundibulum, which is a
funnel-like depression, the walls of which are formed by numerous
narrow processes, called the fimbria. These processes project
from the broad ligament, and are completely covered by
peritoneum. One of them, the fimbria ovarica, is constantly
attached to the upper pole of the ovary. At the bottom of the
infundibulum, the uterine tube communicates with the peritoneal
cavity through the ostium abdominale, and at this point the
peritoneal endothelium merges into the ciliated epithelium
which lines the tube.

As the ova are discharged from the ovary, they pass at once
into the peritoneal cavity, and only those that gain entrance to
the ostium abdominale have any chance of becoming fertilised.
Occasionally, a fertilised ovum fails to be carried along the
tube into the uterus and continues to develop in the tube itself.
This condition is known as tubal gestation, and as the ovum
enlarges, gives rise to abdominal symptoms, which are frequently
misinterpreted. Tubal abortion may occur through the ostium
abdominale, and in this case the haemorrhage varies in severity.
Occasionally, it is excessive and calls for surgical interference.
Failing a tubal abortion, the ovum increases in size until the
uterine tube ruptures, when the extent of the subsequent
haemorrhage will depend on the site of the rupture. If the
tube gives way in the lower two-fifths of its circumference, the
haemorrhage occurs between the two layers of the broad ligament,
and is consequently limited in amount. On the other hand,
if the tube ruptures in the upper three-fifths of its circumference,
the haemorrhage occurs into the peritoneal cavity, and unless
it is restricted by the partial obliteration of the cavity owing
to adhesions, it is so severe that immediate laparotomy is
imperative.

The Ovary is an almond-shaped body about i to i| inches
long by half an inch wide. It projects from the posterior

THE FEMALE PELVIS 393

layer of the broad ligament, which it draws out to form the
mesovarium. It is covered by peritoneum which is somewhat
altered in character, and which is termed " germinal epithelium."

In nulliparae, the ovary lies on the side wall of the pelvis
in a small peritoneal recess, termed the fossa ovarica, which is
limited above by the external iliac vessels and behind by the
ureter. Its medial surface is related to the uterine tube, and
its anterior border is connected to the posterior layer of the
broad ligament by the mesovarium. From its upper pole,
which gives attachment to the fimbria ovarica, the peritoneum
passes to the side wall of the pelvis as the suspensory ligament.
The lower pole of the ovary is attached to the uterus by a
fibro-muscular band, known as the ovarian ligament.

The Ovarian Artery arises from the aorta opposite the
second lumbar vertebra, and passes downwards and laterally
on the psoas major to reach the brim of the pelvis, where it
enters the suspensory ligament. It gives off a few twigs to the
uterine tube, and one or two branches which run medially in the
mesosalpinx to anastomose with the uterine artery, but the
main stem of the vessel enters the mesovarium to supply the
ovary. In the latter part of its course the artery is very tortuous,
and is surrounded by the pampiniform plexus of veins, which
unite to form the ovarian vein in the suspensory ligament.

Owing to the free anastomosis of the ovarian and uterine
arteries, the peritoneum on each side of the ovary must be
seized with forceps when the organ is being removed. Ligature
of the vessels should be carried out by transfixing the broad
ligament, otherwise the sutures may slip and give rise to
troublesome haemorrhage owing to the retraction of the cut
vessels.

Dermoid or other cysts arising in connection with the ovary
may or may not possess a pedicle of peritoneum. When they
do, the pedicle consists of the mesovarium and its contained
vessels. Twisting of the pedicle produces kinking of the artery
and cuts off the blood-supply of the tumour. In other cases,
the cyst may grow in between the two layers of the broad ligament,
and separate them as it enlarges. The peritoneum may be
stripped off the pelvic wall and the iliac colon, and the
commencement of the pelvic colon may be denuded. When
the tumour is removed, great care must be exercised lest these
parts of the bowel be injured, as they are in intimate relationship
with it.

394 THE ABDOMEN AND PELVIS

A large ovarian cyst with a long pedicle may be mistaken
for a movable kidney, as manipulations may be successful in
placing it in the loin (p. 353), but as soon as the manual pressure
is taken away, it tends to sink down towards the pelvis.

The Ep-oophoron (Parovarium) lies between the two layers of the broad
ligament below the ampulla of the uterine tube. Cysts of the ep-oophoron
rarely possess a pedicle, and, as they enlarge, they separate the two layers of
the broad ligament. The ep-oophoron represents a persistent part of the
Wolffian body (p. 267) and consists of a number of small vertical tubules,
which join a horizontal duct. This duct usually ends blindly, but it varies in
length and may be continued downwards to the vagina, where it sometimes
opens. It is then known as the duct of Gartner, and it corresponds to the
ductus deferens in the male.

Cysts may arise in the lower part of the duct and project into the vagina.

Development of the Uterus, etc. — Shortly after the appearance of
the Wolffian ducts (p. 267), two other longitudinal ducts appear. These
are known as the Mullerian ducts. At their cephalic extremities they open
into the body- cavity, and their caudal extremities, though ending blindly at
first, subsequently open into the lowest part of the cloaca. The caudal
two-thirds of the Mullerian ducts fuse to form the uterus and vagina, but
their cephalic thirds remain separate and form the uterine (Fallopian) tubes.
The latter retain their primitive connection with the body-cavity as the ostium
abdominale.

The two Mullerian ducts, although lying side by side, may fail to fuse.
In this case, the vagina is divided into right and left halves by a median
septum and the uterus is bicornuate. The condition of bicornuate uterus
with a normal vagina is not uncommon.

At first, the Mullerian duct is represented by a solid column of cells, which
later become canaliculised. If this process is not carried out completely,
the condition of atresia vagina is brought about.

A few of the tubules of the Wolffian body persist -in the female as the
ep-oophoron (parovarium), and they retain their connection with the Wolffian
duct, which is known, in the adult, as the duct of Gsertner.

Lymph Vessels of the Female Generative Organs. — The

lymph vessels from the body and fundus of the uterus run
laterally in the broad ligament. The majority of them,
accompanied by the lymph vessels from the ovary and the
uterine tube, ascend from the pelvis and join the lumbar lymph
glands. Of the remainder some pass to the external iliac
group and others associate themselves with the round ligament,
to terminate in the medial group of the superficial subinguinal
lymph glands.

The lymph vessels from the cervix uteri and the upper part
of the vagina end in the hypogastric lymph glands, but those
from the posterior aspect establish connections with the ano-
rectal lymph glands (p. 372), on the walls of the rectal ampulla.

The lymph vessels from the lower part of the vagina join the
medial group of the superficial subinguinal lymph glands (p. 400).

The Uterine Artery, a branch of the hypogastric, curves

THE FEMALE PELVIS 395

forwards and medially on the pelvic floor till it reaches the
base of the broad ligament. It then runs medially between
the two peritoneal layers to the lateral border of the uterus.
At a distance of three-quarters of an inch, from the uterus the
uterine artery crosses above and anterior to the ureter, and, in
tying the vessel, great care must be exercised not to include
the ureter within the ligature. In order to avoid this danger,
the artery is usually tied close to the uterus, as it lies above
the lateral fornix of the vagina.

The uterine artery, after giving off a branch which descends
to supply the cervix and vagina, ascends along the lateral border
of the uterus, supplying it with numerous branches. Finally it
ends by supplying the isthmus of the uterine tube and by
anastomosing with branches of the ovarian artery.

Hysterectomy. — The operation of removal of the uterus
has been much simplified by the adoption of the Trendelenberg
position and the abdominal route. Access is obtained by
means of a median infra-umbilical incision (Fig. 76) through
the abdominal wall.

The suspensory ligaments of the ovary and the round
ligaments are seized in forceps, to secure the contained arteries,
and are then divided. The ovary and tube are lifted up on
each side, and, lateral to them, the broad ligaments are divided
medially and downwards towards the uterus. Before the
uterus is reached, artery forceps are passed downwards and
medially to secure the uterine artery in the interval between
the point where it crosses the ureter and the point where it gives
off its descending cervical branch. The peritoneal covering of
the uterus is then incised transversely in front and behind so
as to join the incisions already made in the broad ligaments.
The fingers are inserted into the cellular interval between the
bladder and the cervix, and the two viscera are carefully
separated from one another. The uterus is then dragged up-
wards and the supra- vaginal portion of the cervix is cut through.
All the cut vessels are tied, and, in order to prevent slipping,
the ligatures should be passed through the peritoneum. In
the case of the uterine artery, a secure hold may be obtained
by passing the ligature through the stump of the cervix.
Subsequently, the cut edges of the peritoneum are sutured
together across the floor of the pelvis, all the ligatures being
inverted beneath the peritoneum. The last step in the operation
consists in placing the pelvic colon in the empty pelvis.

396 THE ABDOMEN AND PELVIS

Both in pregnancy and in large tumours the vascular supply
of the uterus is much increased, and the slipping of a ligature
gives rise to formidable haemorrhage.

A Vaginal Examination is best carried out with the patient
in the dorsal position, the thighs being well flexed and abducted.
The labia majora should first be separated, as this act draws
apart the labia minora and prevents their inversion into the
vagina by the examining fingers. The middle and index fingers
are then inserted, and a thorough examination of the vaginal
fornices may be made.

Through the anterior fornix the base of the bladder can be
felt, and, when the surgeon uses his free hand to exert pressure
on the anterior abdominal wall in a downward and backward
direction, the body of the uterus can also be examined, if it is
in the normal position. In the lower part of the anterior vaginal
wall, the urethra can be recognised as a rounded cord and may
be rolled against the arcuate (subpubic) ligament.

Through the posterior fornix, the fingers can palpate the
contents of the utero-rectal fossa. A prolapsed ovary is at once
recognised on examination by the characteristic sensation
aroused in the patient. The rectum lies in close contact with
the lower part of the posterior vaginal wall, and scybalous masses
can be recognised by the fact that they pit on pressure. When
the rectum is empty, the sacral promontory can be reached
with the tip of the forefinger. The distance between it and the
pubic symphysis can be estimated ; normally, it amounts to
4| inches.

Through the lateral fornices, the conditions of the broad
ligaments may be estimated, and tumours, collections of pus
in the uterine tubes, or the enlargement due to extra-uterine
pregnancy may be recognised.

The uterine tubes, when healthy, cannot be palpated, but
in the presence of salpingitis they can readily be made out on
vaginal examination. When a calculus is impacted in the lower
part of the ureter, it may sometimes be located per vaginam,
but the normal ureter, like the normal tube, cannot be felt
through the fornix.

The Female Perineum. — The rectal triangle shows no differences of
importance, and the description given on pp. 373-375 holds good for this area
in the female.

In the urogenital triangle the sexual differences require further description.

The labia majora are two folds of skin which surround the urogenital
fissure. They commence in front at the mons veneris, a rounded elevation on

THE FEMALE PELVIS 397

the front of the pubes, and extend backwards, meeting to form the posterior
commissure just anterior to the anus. Their inner surfaces are covered by
slightly modified skin, which is kept moist by the secretion of numerous
sebaceous glands.

The labia minora are two folds of skin which lie within the urogenital
fissure, one on each side of the vaginal orifice. Anteriorly each splits into
upper and lower parts. The upper parts of the two sides unite above the
clitoris and form the prceputium ditoridis. The lower parts are attached to
the under surface of the clitoris and constitute thefrenulum.

The clitoris is homologous with the glans penis and possesses a similar
structure, but it is very much smaller in size and is not traversed by the urethra.
Dorsally it consists of two corpora cavernosa, which are covered distally
by the glans. In place of the corpus cavernosum urethrae of the male, the
ventral aspect of the body of the clitoris is occupied by a venous plexus,
termed the pars intermedia, which is continuous in front with the erectile
tissue of the glans.

The root of the clitoris consists of two crura and the bulb of the vestibule,
and it lies in the superficial perineal pouch (p. 376). The crura, as in the male,
are attached to the borders of the pubic arch and are covered by the ischio-
cavernosi muscles. The bulb of the vestibule consists of two elongated bodies,
composed of erectile tissue, which lie one on each side of the entrance to the
vagina. In front they are continuous with one another and with the pars
intermedia. During the stretching of the vaginal walls in parturition or from
trauma these venous plexuses may be injured and give rise to a haematoma.
The bulb is covered by the bulbo-cavernosus (sphincter vaginae) muscle.

Between the glans clitoridis and the orifice of the vagina there is a smooth
triangular area, which is pierced by the external opening of the urethra.
This area is termed the vestibule.

The vaginal orifice in the virgin is partly obscured by the hymen, which
consists of two folds of mucous membrane of varying shape and size. Some-
times the hymen is imperforate, and, with the onset of puberty, the condition
gives rise to trouble by obstructing the menstrual flow.

The glandulce vestibulares majores (of Bartholin) correspond to the bulbo-
urethral glands in the male (p. 384). They lie on the lateral vaginal wall,
under cover of the bulbo-cavernosus muscle, and their ducts open in the
interval between the hymen and the labia minora. These glands may
become infected in gonorrhoea and give rise to abscess formation.

The Female Urethra is only i£ inches long, and throughout
its whole extent it is closely related to the anterior wall of the
vagina. As in the male, the urethra pierces the urogenital
diaphragm,, but its course in the superficial perineal pouch is
extremely short, as it almost at once opens on the surface of the
vestibule. It follows a slightly curved course, the concavity
of the curve being directed forwards, and it can readily be
dilated so as to permit of direct examination of the interior of
the bladder. The ureteral orifices can be inspected and direct
catheterisation can be carried out.

The vessels and nerves of the urogenital triangle in the male
have been described on p. 377, and require no further mention.

398 THE INFERIOR EXTREMITY

THE INFERIOR EXTREMITY.

THE FRONT OF THE THIGH.

Surface Landmarks. — The bony points of the pelvis have
already been described (pp. 237 and 239).

> ... The sartorius muscle is rendered prominent when the hip and
knee-joints are flexed and the limb is rotated laterally. It can
then be recognised as a ridge passing from the anterior superior
iliac spine obliquely to the medial side of the thigh. To its
lateral side, just distal to the anterior superior spine, the ringers
can be inserted into a depression, which is bounded laterally
by the tensor Jascicz latce. This depression overlies the straight
head of the rectus femoris — which lies on the anterior aspect of
the capsule of the hip- joint — and it is rendered more distinct
when the patient flexes the thigh with the knee extended.

The tendon of the adductor longus, which arises in the angle
between the pubic crest and the symphysis, can be seen when
the thigh is adducted against resistance. In obese subjects,
though not always visible, the tendon can be felt and traced
to the pubis. The tendon may serve as a guide to the pubic
tubercle, the position of which must be determined in distin-
guishing a femoral from a small inguinal hernia. The neck of
a femoral hernia lies below the tubercle, while that of an inguinal
hernia is situated above it.

Superficial Vessels.— -The great saphenous vein (p. 447)
lies in the superficial fascia on the antero-medial side of the
thigh, and, having received numerous tributaries, pierces the
fascia cribrosa, which partially closes the fossa ovalis (saphenous
opening), to join the femoral vein.

Its proximal part is commonly exposed by the surgeon in
the removal of varicose veins, and is most easily found by
making a transverse incision through the skin and fascia at the
distal border of the fossa ovalis (p. 401), the patient's limb
being kept slightly abducted and laterally rotated.

At the point where the great saphenous joins the femoral
vein there is not uncommonly a dilatation, which gives rise to a
visible swelling. This may be mistaken for a femoral hernia,
as there is an impulse on coughing and the swelling disappears

THE FRONT OF THE THIGH

399

For the purpose of differential

when the patient lies down,
diagnosis, the patient is
examined in the recumbent
posture, and a finger is
placed on the proximal part
of the fossa ovalis so as to
control the femoral vein
and also a femoral hernia,
if one is present. The
patient is then allowed to
resume the erect attitude.
The swelling, if venous in
nature, gradually reappears
from below as the veins fill
up.

The superficial epigastric
and external pudendal arteries
have been described on p.
253. The superficial cir-
cumflex iliac pierces the deep
fascia lateral to the fossa
ovalis and passes laterally
(p. 409). All three are de-
rived from the femoral
artery.

The Cutaneous Nerves which
supply the skin of the front of
the thigh arise from the lumbar
plexus.

1. The lateral cutaneous (L. nerve
2, 3) enters the thigh behind

the lateral extremity of the in-
guinal ligament, and runs behind
the deep fascia for two inches
before breaking up into anterior
and posterior divisions, which
pierce the deep fascia to supply D eal nerve

the skin of the buttock and of (O.T. ant. tibial)"
the lateral aspect of the thigh as
far as the knee.

2. The lumbo-inguinal nerve
(crural branch of the genito- crural)
(L. i, 2) supplies an area of skin
distal to the intermediate part of

the inguinal ligament. It varies greatly in size, and sometimes extends to
the region of the knee. In renal colic, pain is sometimes referred to the
areas supplied by the lumbo- and ilio-inguinal nerves (p. 354).

Lateral cutaneous
nerve of the thigh

Ilio-inguinal nerve
Lumbo-inguinal - — ^

nerve

Branch from
medial cutaneous"
nerve of the thigh
Intermediate cuta-
neous nerve
of the thigh
Medial cutaneous-
nerve of the thigh

Great saphenous
vein"

Anterior part of
medial cutaneous-
nerve of the thigh

Infrapatellar branch
of saphenous nerve"

Great saphenous
vein"

Saphenous nerve.
Superficial peroneal

FIG. 118. — The Superficial Nerves and
Veins on the Anterior Aspect of the
Lower Limb.

400 THE INFERIOR EXTREMITY

3. The intermediate cutaneous (L. 2, 3) is a branch of the femoral (anterior
crural) nerve. It supplies the skin of the front of the thigh as far as the
knee (Fig. 118).

4. The medial cutaneous (L. 2, 3), also a branch of the femoral nerve,
supplies the antero-medial aspect of the thigh. In the distal part of its
course it is associated with the great saphenous vein.

5. The ilio-inguinal (L. i) (p. 240) supplies a few branches to the skin of
the proximal and medial part of the thigh.

6. The obturator nerve (L. 2, 3, 4) sends some branches through the sar-
torial plexus (p. 41 1), which are distributed posterior to the medial cutaneous
nerve.

The Superficial Subinguinal Lymph Glands, which lie
on the deep fascia distal to the inguinal ligament, are subdivided
into two groups, (a) The proximal group consists of a chain of
lymph glands which lie distal to and, roughly, parallel with
the inguinal ligament. The lateral members of the group
receive afferents from the perineum, anus, buttock, and the
abdominal wall, below the umbilicus ; the medial glands receive
afferents from the anus, perineum, and external genitalia. (b)
The distal group lies around the proximal part of the great
saphenous vein and on the lateral border of the fossa ovalis
(saphenous opening). This group receives all the superficial
lymph vessels of the lower limb, except those from the buttock
and those from the lateral side of the foot and the postero-
lateral area of the leg, which enter the popliteal glands (p. 446).

Lymphangitis from septic conditions of the toes may cul-
minate in suppurative adenitis of the distal subinguinal glands.
In these cases the thigh is usually kept in the position of flexion
in order to relax the overlying skin and cutaneous nerves.

The efferents from both groups of the superficial subinguinal
lymph glands terminate in the deep subinguinal glands, which
lie behind the deep fascia around the proximal parts of the
femoral vessels. Abscesses in connection with this group
should, therefore, be opened by Hilton's method. The efferents
from the popliteal glands also end in the deep group, which sends
its own efferents to the external iliac lymph glands. The
most proximal member of the deep group occupies the femoral
ring (p. 403).

The Deep Fascia is attached proximally to the body and
tubercle of the pubis, to the inguinal ligament and the anterior
superior iliac spine. Laterally, it encloses the tensor fasciae
latae and reaches the gluteal region. On the medial side it is
attached to the margins of the pubic arch as far as the ischial
tuberosity, where it becomes continuous with the deep fascia

THE FRONT OF THE THIGH

401

of the back of the thigh. It is particularly strong over the lateral
aspect of the thigh, where it is strengthened by the insertions
of the tensor fasciae latse and glutseus maximus. This part of
the fascia lata is known as the ilio-tibial tract.

Cut edge of Scarpa's fascia
Lumbo-inguinal nerve

Femoral vessels

Superior horn of falciform margin
Subcutaneous inguinal ring
Pectineal part of fascia femoris |

Spermatic cord
Superficial external
pudendal artery

Superficial epigastric
artery

Superficial circum-
flex iliac artery
Lymph gland
Iliac portion of
fascia lata

Lateral cutane-
ous nerve of the

Inferior horn of falciform
margin of fossa ovalis.j
Great saphenous ve

Anterior and posterior (
branches of the medial <
cutaneous nerve (O.T. V
internal cutaneous)

FIG. 119. — The Subinguinal Lymph Glands and the Fossa Ovalis
(Saphenous opening).

A large gap,, termed the fossa ovalis (saphenous opening),
occurs in the deep fascia just distal to the medial end of the
inguinal ligament. The centre of the opening lies i| inches
distal and lateral to the pubic tubercle (Stiles). It is traversed
by the great saphenous vein and is partially closed by the fascia
cribrosa. The lateral border of the fossa ovalis is sharp and
well denned. It is falciform in outline, and its superior cornu

26

402 THE INFERIOR EXTREMITY

(Key's ligament} arches proximally and medially to reach the
pubic tubercle, where it blends with the lacunar ligament (of
Gimbernat). The inferior cornu (Burns' ligament) is also well
marked, and lies just distal to the point of union of the great
saphenous and femoral veins (Fig. 119). The medial border of
the fossa is poorly denned. It is formed by the fascia over the
pectineus, and, when traced laterally, it disappears behind the
femoral sheath and blends with its posterior wall.

The fossa ovalis is i| inches long by half an inch wide, and
is of particular importance because it represents the distal
opening of the track taken by a femoral hernia after it has
passed through the femoral (crural) ring (p. 403).

The lateral intermuscular septum is a strong partition which
connects the deep fascia to the lateral lip of the linea aspera
of the femur. It separates the vastus lateralis from the femoral
head of the biceps, and thus forms a partition between the
extensor and flexor compartments of the thigh. Incisions to
expose the diaphysis of the femur are made in front of the line
of the lateral intermuscular septum (p. 437).

The medial intermuscular septum separates the adductor
from the extensor compartment of the thigh. As it covers the
anterior surfaces of the adductor longus and magnus, it forms
the fascial floor of the adductor canal (of Hunter).

The Femoral Sheath is a sleeve-like prolongation of the
fascial envelope of the abdomen (p. 271) which passes down into
the thigh behind the inguinal ligament. Lateral to the femoral
vessels, both the fascia transversalis and the fascia iliaca are
attached to the inguinal ligament; but opposite the vessels,
which intervene between the two layers, they are carried into
the thigh to form the femoral sheath (Fig. 120).

Two fascial septa divide the sheath into three compartments ;
the lateral compartment contains the femoral artery and the
lumbo-inguinal nerve and is the longest of the three (Fig. 121).
The middle compartment contains the femoral vein. The
medial compartment, which is the shortest of the three, only
contains some extra-peritoneal fat and one of the deep sub-
inguinal lymph glands, which together constitute the septum
femorale (crurale) ; it is known as the femoral (crural) canal, and
is of great importance because it constitutes the passage through
which a femoral hernia enters the thigh.

The femoral sheath is related anteriorly to the fascia lata
and the fossa ovalis ; posteriorly, it rests on the pectineus,

THE FRONT OF THE THIGH

403

medially, and on the psoas major, laterally. Between these
two muscles the posterior wall of the sheath is connected to the
capsule of the hip-joint.

The mouths of the central and lateral compartments of the
sheath are completely filled by their contents, but the mouth
of the femoral canal, which is termed the femoral (crural) ring,
is occupied only by a lymph gland, and therefore constitutes
a weak point in the fascial envelope of the abdomen. In addi-
tion to its fascial walls, the femoral ring is bounded anteriorly

Skin

Fascia of Camper
Fascia of Scarpa
Ext. oblique aponeurosis
Int. oblique

Transversus
Fascia transversalis-
Peritoneun

Fascia iliaca'
Femoral ring"
Deep subinguinal gland
Septum femorale.
Pectineus-
Fossa ovalis-

Superior ramus of pubis

FIG. 120.— Diagram of a Sagittal Section through the lower part of the
Abdomen and the proximal part of the Thigh. The section passes
through the femoral canal and demonstrates the mode of formation of
the femoral sheath.

by the inguinal ligament, laterally by the femoral vein, pos-
teriorly by the pectineus and the subjacent ramus of the pubis,
and medially by the free, lateral margin of the lacunar ligament
(of Gimbernat).

In a Femoral Hernia the bowel pushes the parietal peri-
toneum of the lower part of the anterior abdominal wall and
the extra-peritoneal fat (septum femorale, p. 402) through the
femoral ring into the femoral canal. It stretches the anterior
wall of the sheath and thus gains another covering. The sac,
together with its coverings, passes through the fascia lata at
the fossa ovalis, and then, following the course of least resist-
ance, bends upwards towards the anterior superior iliac spine

26 a

404 THE INFERIOR EXTREMITY

in the lax, fatty space which contains the proximal subinguinal
lymph glands.

During attempts to reduce a femoral hernia the thigh should
be semiflexed and slightly adducted in order to relax the pec-
tineus, the fascia lata, and the inguinal ligament. Gentle
manipulations are then carried out to make the protrusion
retrace the course of its original path, first distally and medially
till it passes through the fossa ovalis, and finally, backwards
and proximally through the femoral ring.

The surgical approach may be by means of an incision parallel
and just distal to the medial part of the inguinal ligament,
or a semilunar incision may be utilised, the base of the flap
being medial, with the object of keeping the wound as far as
possible from the genitalia. After division of the skin, super-
ficial fascia and vessels, a little blunt dissection reveals a mass
of fat quite distinct from the surrounding fatty areolar tissue.
The coverings derived from the fascia cribrosa and the wall of
the femoral canal can rarely be identified. Further blunt dis-
section is carried out until the neck of the tumour is isolated at
the femoral ring, and while this is being done the union of the
great saphenous with the femoral vein may be exposed just
proximal to the distal edge of the fossa ovalis. The fatty tissue,
which consists of the septum femorale, is then carefully incised
step by step in a search for the hernial sac. Sometimes there
is no sac and the tumour is simply a lipoma growing in the
septum femorale. If a sac is found it is carefully isolated,
ligated, and transplanted upwards by carrying the long ends of
the ligatures upwards through the femoral ring and bringing
them out above the inguinal ligament and there tying them.

Many methods have been introduced in order to close, narrow,
or obstruct the femoral canal, but owing to the rigidity of the
parts above and the constant movements of the parts below,
none of them have proved altogether satisfactory. A strong
purse-string catgut suture may be utilised to pucker up the fascia
in the region. It is passed through the inguinal ligament, the
fascia lata, the lateral border of the fossa ovalis, and the fascia
over the pectineus, and care must be taken not to injure the
femoral vein. Another method is to dissect up a flap of the pec-
tineal fascia and stitch it to the inguinal ligament, thus closing
the femoral ring.

Femoral hernia occurs more frequently in women than in
men. This is partly on account of the greater width of the

THE FRONT OF THE THIGH 405

pelvis and the increased size of the femoral ring, and partly
because the peritoneal fossa, which lies opposite the ring, is
more pronounced in the female. In young girls and female
infants inguinal hernia (p. 264) is the commoner variety, but
after puberty femoral hernia is the commoner of the two.

Owing to the narrowness of the canal and the unyielding
character of its walls, the occurrence of irreducible femoral
epiplocele is not uncommon, and femoral hernias frequently
become strangulated. In operating on a strangulated femoral
hernia, some difficulty may be experienced in recognising the
sac when it is reached on account of the cedema and congestion.
All the layers must be divided until the escape of the discoloured
fluid from within the sac indicates the proximity of the bowel.
Before the condition of the gut at the constricted neck can be
examined and the hernia reduced the femoral ring must be en-
larged. Owing to the nature of the boundaries of the ring
(p. 403) this can only be carried out on the medial side. A
director is passed along the medial side of the neck of the sac
and a guarded knife is introduced. Two. or three small incisions
are made in the free edge of the lacunar ligament (of Gimbernat),
until the opening is sufficiently enlarged to permit of the bowel
being withdrawn for examination. In a very small percentage
of cases this proceeding is at once followed by severe haemorrhage,
due to injury of an abnormal obturator artery. Normally the
obturator artery (p. 411) arises from the hypogastric, but in
about 20 per cent of cases it arises from the inferior (deep)
epigastric (Fig. 121). In its subsequent course towards the
obturator foramen it may pass either to the medial or lateral
side of the femoral ring. When the artery passes medial to
the ring it is apt to be injured when the lacunar ligament is
incised in relieving the strangulation of a femoral hernia. If
the bleeding points cannot be caught it will be necessary to cut
down on and ligature the inferior epigastric artery (p. 253).

Cold abscesses originating in connection with the vertebral
column or the hip- joint may give rise to a swelling in the proximal
part of the thigh. As they possess an impulse on coughing,
and disappear or decrease in size in the recumbent position,
they may be mistaken for femoral hernise. The point at which
they emerge from behind the inguinal ligament may clear up
the diagnosis, for the neck of a femoral hernia is always placed
distal to the medial extremity of the ligament, whereas a cold
abscess appears to the lateral side of the femoral vessels (p. 522).

4o6 THE INFERIOR EXTREMITY

The Femoral Trigone (of Scarpa) is a triangular space lying immediately
distal to the inguinal ligament, which forms its base. Its oblique lateral
boundary, formed by the sartorius, and its straight medial boundary, formed
by the medial border of the adductor longus, meet one another at the apex
of the triangle.

The floor of the space is formed, in its lateral part, by the iliacus and
psoas major, as they cross the front of the hip- joint to reach the lesser tro-
chanter. The medial part of the floor is formed by the pectineus proximally
and the adductor longus distally (Fig. 121).

The most important contents of the space are the femoral vessels and
nerve, together with their large branches.

The Femoral (Anterior Crural) Nerve (L. 2, 3, 4)
enters the thigh by passing behind the inguinal ligament half
an inch lateral to the femoral artery. In the pelvis the nerve
lies deep to the fascia iliaca. In the thigh it lies in the groove
between the psoas major and the iliacus, and is covered over by
the fascia lata, which is usually thickened in this situation.
The nerve at once breaks up into (i) cutaneous, (2) muscular,
and (3) articular branches.

(1) The medial and intermediate cutaneous nerves are de-
scribed on p. 400.

The saphenous nerve (L. 3 and 4) runs medially and distally
towards the femoral artery, and at the apex of the femoral
trigone it enters the adductor canal (of Hunter). It leaves the
canal at its distal end and pierces the deep fascia near the
adductor tubercle, where it becomes associated with the great
saphenous vein. Its terminal branches are distributed to the
medial side of the leg and foot (p. 499).

(2) The muscular branches of the femoral nerve supply the
pectineus, the sartorius, and the quadriceps extensor.

(3) Articular branches arise from the nerves to the vasti
and supply the knee-joint, while the nerve to the rectus femoris
gives off a branch to the hip-joint. In addition to receiving
branches from the femoral nerve, both joints are supplied by
the obturator nerve (p. 411). It is not uncommon to find that,
in tuberculous disease of the hip-joint, the pain is entirely re-
ferred to the knee. Whether the pain is referred to the joint or
to the overlying skin, which is also supplied by branches of the
femoral nerve, is by no means certain.

The Femoral Artery is the direct continuation of the
external iliac. It enters the thigh behind the inguinal ligament
at a point midway between the symphysis pubis and the anterior
superior iliac spine ; and its course is represented by the proximal
two-thirds of the line joining this point to the adductor tubercle,

THE FRONT OF THE THIGH

407

when the thigh is slightly flexed, abducted, and laterally
rotated.

In its proximal half the artery lies immediately behind the
deep fascia covering the femoral trigone. -It may be compressed
against the head of the femur, but owing to the shape of the
latter, this method of occluding the vessel is unreliable. The

Deep circumflex iliac artery

Inferior epigastric artery
\

Abnormal obturator artery

*&)

Lymph gland in

femoral canal

Septa in femoral

sheath

Saphenous nerve

Spermatic cord
Lower end of
femoral sheat
Superficial extern;
pudendal artery

Sapheno
Adductor longus

Medial cutaneous
nerve

Lateral cutaneous
nerve

Tensor fasciae latae

Lateral edge of
femoral sheath

Intermediate
cutaneous nerve

Rectus femoris

FIG. 121. — The Femoral Trigone (of Scarpa). The anterior wall of the
femoral sheath has been removed. The inferior epigastric and the
deep circumflex iliac arteries arise at a lower level than normal, and
the former gives off the abnormal obturator artery.

vessel is usually compressed distally and backwards against the
superior ramus of the pubis, which it crosses as it enters the
thigh. In cases of disarticulation at the hip-joint, where the
vessel is not at once exposed and ligated, the most satisfactory
method of arresting hsemorrhage is by compression of the
abdominal aorta just above its bifurcation (Macewen).

Ligature of the femoral artery may be carried out close

266

408 THE INFERIOR EXTREMITY

to its origin, for aneurism, or following wounds of the vessel, or
as a preliminary step to a disarticulation at the hip- joint. The
incision may be made in the course of the artery or at right
angles to it. In the latter case the lumbo-inguinal nerve (p.
399) is usually divided, and the femoral vein, which lies medial
to the artery, and the femoral nerve, which lies to its lateral side,
run risk of injury. When the skin and superficial fascia have
been divided, only the fascia lata and the anterior wall of the
femoral sheath, which is usually adherent to it, have to be
incised before the artery is exposed.

After ligature of the femoral artery at this site, the circulation
is re-established (i) through the anastomosis of the deep circum-
flex iliac, from the external iliac, with the superficial circumflex
iliac and the ascending branch of the lateral circumflex ; and
(2) through the anastomosis in the region of the quadrate
tubercle (p. 419), where the gluteal branches from the hypo-
gastric (internal iliac) anastomose with branches which arise
from the femoral on the distal side of the ligature.

Axial anastomosis of the femoral artery and vein has
been carried out in this situation in cases of threatened gangrene.
The vessels are divided and the proximal end of the artery is
sutured to the distal end of the vein, while the proximal end of
the vein is similarly sutured to the distal end of the artery. In
this way an endeavour is made to reverse the course of the
blood-stream in the lower limb.

Ligature of the femoral artery at the apex of the
femoral trigone is carried out by means of an incision along
the line of the vessel. The sartorius is identified and retracted
to the lateral side, exposing the artery just before it enters the
adductor canal (of Hunter). In this situation the vessel is
crossed by the medial cutaneous nerve, and the saphenous nerve
may be either an anterior or. a lateral relation. Although lying
to the medial side of the artery in the proximal part of the
thigh, the femoral vein occupies a posterior position at the apex
of the trigone, and care must be taken not to injure it when pass-
ing the ligature. On this account the fibrous sheath of the
artery is opened on its antero-lateral aspect.

After ligature of the artery at this site, the circulation is re-
established by means of the anastomosis round th'e knee-joint
(p. 445), where branches which arise from the femoral on the
proximal side of the ligature communicate with others which
arise on the distal side.

THE FRONT OF THE THIGH 409

The Quadriceps Femoris acts as a powerful extensor of the knee-joint.
It consists of four muscles, which are inserted into the proximal border of the
patella by a common tendon. They are all supplied by the femoral nerve
(L. 3 and 4).

(i) The Rectus Femoris arises by a straight head; from the anterior inferior
iliac spine, and by a reflected head, which joins the former almost at right
angles, from the dorsum ilii just above the acetabulum. Near its origin
the muscle lies at the bottom of the depression between the tensor fasciae latae
and the sartorius (p. 398), and is in close relation to the anterior aspect of
the capsule of the hip-joint. After it has been crossed by the sartorius the
muscle becomes superficial, and it forms a well-marked elevation in the
middle line of the thigh when the knee is extended.

(2) The Vastus Intermedius (Crureus) arises from the anterior and lateral
aspects of the shaft of the femur. It is partially overlapped by (3) the
Vastus Lateralis and (4) the Vastus Medialis. Both these muscles possess
linear origins from the linea aspera and the proximal part of the shaft of
the femur, but although the vastus medialis covers the medial aspect of the
bone, it gets no fibres of origin from it.

At the sides of the patella the capsule of the knee- joint is greatly strengthened
by tendinous expansions, which it receives from the vastus lateralis and medialis.

The Sartorius (p. 398) forms the lateral boundary of the femoral trigone
and the roof of the adductor canal, and then descends vertically on the medial
aspect of the thigh. It is inserted into the proximal part of the medial
surface of the tibia. The sartorius acts as a flexor and medial rotator of the
tibia, and as a flexor, abductor, and lateral rotator of the femur. It is
supplied by the femoral nerve (L. 3 and 4).

Branches of the Femoral Artery.— Near its commence-
ment the femoral artery gives off the superficial external pudenda!
(p. 253), the superficial epigastric (p. 253),, and the superficial
circumflex iliac. The last named runs laterally, parallel to the
inguinal ligament, and terminates in the anastomosis around the
anterior superior iliac spine (p. 416).

The Deep External Pudendal Artery runs medially behind
the femoral vein and on the pectineus to supply the skin of the
scrotum.

The Profunda Femoris usually arises about i| inches distal
to the inguinal ligament, and descends at first lateral and then
posterior to the femoral vessels. At the upper border of the
adductor longus the profunda leaves the femoral vessels by
passing behind the muscle.

The profunda gives origin to several important branches.

i . The Lateral Circumflex, which sometimes arises from the
femoral, springs from the profunda close to its origin. It passes
laterally, deep to the rectus and sartorius, where it is exposed
in the anterior route for excision of the hip (p. 434), and then
breaks up into : (a) an ascending branch, which joins the ana-
stomosis round the anterior superior spine of the ilium (p. 416) ;
(b) a transverse branch, which helps to form the crucial ana-

4io THE INFERIOR EXTREMITY

stomosis (p. 418) ; and (c) a descending branch, which joins
the anastomosis round the knee-joint.

2. The Medial Circumflex, which frequently arises from
the femoral, takes origin opposite the lateral circumflex, and
runs backwards between the pectineus and the psoas major.
It passes below the neck of the femur and ends in the crucial
anastomosis (p. 418).

3. The four perforating arteries arise from the profunda
more distally. They wind round the back of the femur, giving
off branches to the adductors, and gain the back of the thigh.
There they form a series of anastomotic arches with one another.
In addition, the first perforating joins the crucial anastomosis
(p. 418), and the fourth, which is the terminal branch of the
profunda, anastomoses freely with branches from the popliteal

(P- 445)-

The Pectineus arises from the superior ramus of the pubis, and passes
laterally and distally to be inserted into the posterior aspect of the proximal
part of the shaft of the femur. It is supplied by the femoral nerve (L. 2 and
3), and acts as an adductor and flexor of the thigh.

The Adductor group consists of four muscles, and they are all supplied
by the obturator nerve (L. 2, 3, 4).

1. The Gracilis is a thin, flattened muscle which extends from the margin
of the pubic arch along the medial side of the thigh. As it is inserted into
the proximal part of the tibia near the semitendinosus (p. 441), it acts more
powerfully as a flexor of the knee than as an adductor of the hip. In paralysis
of the ham-strings, flexion of the knee-joint is carried out satisfactorily
by the gracilis, assisted by the sartorius.

2. The Adductor Longus (p. 398) helps to form the floor of the femoral
trigone and the posterior wall of the adductor canal, and consequently
supports the femoral artery in a considerable part of its course. It is the
most anterior of the three principal adductors, and is inserted into the linea
aspera.

3. The Adductor Brevis lies behind the upper part of the adductor
longus. It extends from the front of the pubis to the back of the femur.
Its upper border is in contact with the outer surface of the obturator externus.

4. The Adductor Magnus is the largest and most posterior of the three
principal adductors. It arises from the margin of the pubic arch and from
the lower part of the ischial tuberosity. The upper fibres are horizontal
and reach the femur just distal to the quadrate tubercle ; the lower fibres
are almost vertical, and are inserted into the adductor tubercle (p. 443) ;
the other fibres extend obliquely to the linea aspera and the medial supra-
condylar ridge. By reason of its vertical fibres, the muscle possesses a
secondary action as an extensor of the hip-joint. In its upper part the an-
terior surface of the magnus is covered by the brevis, but below the lower
border of that muscle it is in contact with the longus, and, below the longus,
the magnus forms the posterior wall of the adductor canal. In the latter
part of its extent it possesses a large gap, the hiatus tendineus, which trans-
mits the femoral vessels to the popliteal fossa.

The adductor magnus receives an additional nerve-supply from the sciatic
(L. 4, 5, and S. i).

The Obturator Externus arises from the outer surface of the obturator

THE FRONT OF THE THIGH 411

membrane and the medial margin of the foramen, and its tendon passes
laterally, to be inserted into the trochanteric fossa. It lies deeply in the
interval between the quadratus femoris and the inferior gemellus, and is at
first below and then posterior to the capsule of the hip-joint. It is supplied
by the posterior branch of the obturator nerve (I,. 3 and 4), and acts as a
powerful lateral rotator of the thigh.

Owing to the tilt of the pelvis, the outer surface of the muscle is directed
distally, laterally, and forwards. It is in relation to the pectineus and the
adductor brevis.

The Obturator Nerve (L. 2, 3, 4) breaks up into an
anterior and a posterior division as it enters the upper part
of the obturator foramen. The anterior division leaves the pelvis
above the obturator externus, and passes distally, first between
that muscle and the pectineus, and then between the adductors
brevis and longus. It supplies the two last-named muscles
and the gracilis, and in addition gives an articular branch to
the hip- joint. Further, it gives origin to a small branch
which unites with a similar branch from the medial cutaneous
to form the sartorial plexus. Twigs from this plexus, which
lies deep to the sartorius, supply the skin on the medial side
of the thigh.

The posterior division pierces the upper part of the obturator
externus, which it supplies, and descends on the deep surface
of the adductor brevis. It supplies the adductor magnus and
gives off a fine articular branch to the knee-joint (p. 406).

The Obturator Artery (p. 405) accompanies the anterior
division of the obturator nerve through the foramen. It
divides into two branches, which encircle the obturator mem-
brane deep to the obturator externus, supplying the muscle
and giving off a branch to the hip- joint (p. 438).

Obturator Hernia is of rare occurrence. It follows the
vessels and nerve through the upper part of the obturator
foramen but has no constant relation to them. The protrusion,
however, causes pressure on the nerve and gives rise to Romberg's
symptom. This consists in tenderness of the adductors, and
pain referred to the cutaneous distribution of the obturator
nerve on the medial side of the thigh.

The hernia, which is usually strangulated, lies behind the
pectineus and on the surface of the obturator externus, causing
a small, ill-defined swelling in the medio-proximal part of the
thigh ; the thigh is kept flexed in order to relax the pectineus,
and attempts to produce extension cause severe pain. Adduc-
tion is also resisted, as this movement tends to squeeze the
hernia against the obturator externus.

4i2 THE INFERIOR EXTREMITY

The Adductor Canal (of Hunter) is an intermuscular
space on the medial side of the middle third of the thigh, and
it contains the femoral artery and vein and the saphenous nerve.
The roof of the canal is formed by the sartorius and a strong
layer of deep fascia, which lies behind the muscle. The lateral

Vastus medialis

Profunda femoris artery | Femoral vein
Vastus intermedius | | I Saphenous nerve
Femur | | | | | Femoral artery

Rectus femoris

Sartorius
Biceps | Gracilis

Semitendinosus | | Adductor Longus

Sciatic nerve | | Adductor brevis

Adductor magnus Seinimembranosus

FIG. 122. — Transverse Section through the Thigh, a little distal to the
junction of the proximal and middle thirds. The lateral intermuscular
septum is well shown, and the femoral vessels are seen in the abductor
canal (of Hunter).

wall is formed by the vastus medialis, while the posterior wall
is formed by the adductor longus proximally and the adductor
magnus distally. At the distal end of the canal there is a wide
gap in the insertion of the latter muscle, and through this
opening, which is termed the hiatus tendineus, the femoral artery
enters the popliteal fossa.

It may be necessary to ligature the femoral artery in the

THE GLUTEAL REGION 413

adductor canal following stab wounds or in cases of popliteal
aneurism. The incision is made in the line of the vessel, and
as it is deepened through the superficial fascia, the great saphen-
ous vein or one of its tributaries may require to be retracted.
The deep fascia over the sartorius is very thin, and when it has
been divided the muscle may be recognised by the direction of
its fibres. After the sartorius has been retracted medially the
strong fascial roof of the canal is incised, and the femoral artery
is exposed with the saphenous nerve on its anterior surface.
The femoral vein lies posterior to the artery in the proximal
part of the canal, but distally it inclines to the lateral side.
In passing the aneurism needle care must be taken to avoid
injuring the vein.

After ligature of the femoral artery in the adductor canal,
the collateral circulation is re-established (i) through the ana-
stomosis between the descending branch of the lateral circumflex
(p. 409) and the arteria genu suprema (anastomotica magna),
and (2) through the anastomosis between the fourth perforating
artery (p. 410) and branches of the popliteal (p. 445).

The arteria genu suprema arises from the femoral just before
it leaves the adductor canal. It divides into a saphenous
branch, which becomes superficial, and an articular branch.
The latter enters the vastus medialis and descends on the femur
to take part in the anastomosis around the knee-joint (p. 445).

THE GLUTEAL REGION.

Bony Landmarks. — The ischial tuberosity lies vertically
below the posterior superior iliac spine. It is deeply situated
under cover of the glutseus maximus when the thigh is extended ;
and when the thigh is flexed, although the muscle slips over the
tuberosity, the skin and fascise are no longer relaxed, so that
the recognition of this bony point becomes more difficult.

The greater trochanter of the femur lies a hand - breadth
below the tubercle on the iliac crest (p. 237). In a normal
subject its position is indicated by a flattened depression on
the lateral aspect of the proximal part of the thigh, but in wasted
subjects it becomes a very prominent projection. Its lateral
aspect is about two inches long by i| inches wide, and its margins,
more especially the posterior, can readily be felt when the deep

4i4 THE INFERIOR EXTREMITY

fascia, which tends to obscure them, is relaxed by passively
abducting the thigh. When the limb is in this position the
fingers can sink into the trochanteric (digital) fossa posteriorly,
but this depression is occluded in fractures in this neighbourhood.
The greater trochanter may become distorted, following its
implication in fractures or infective disease. Increase in size
can be determined and the two sides compared by encircling
both prominences with the fingers and thumbs.

The lesser trochanter can be felt by palpating deeply beneath
the gluteal fold in the medial aspect of the thigh, when the limb
is extended and medially rotated.

The iliac crests and spines have been described on pp. 237, 239.

The Muscular Landmarks of the buttock are obscured
by the thick fatty superficial fascia, but the outline of the
glutczus maximus can sometimes be seen. Its lower border
crosses the centre of the gluteal fold obliquely downwards and
laterally, and disappears in the general contour of the lateral
aspect of the thigh. The upper border of the muscle descends
obliquely from the posterior part of the iliac crest towards the
apex of the greater trochanter. When the thigh is actively
rotated medially, a muscular elevation at once appears just
below and lateral to the anterior superior iliac spine. It con-
sists of the tensor fascia latce superficially and the glutceus
minimus deeply.

The Cutaneous Nerves of the buttock are derived from numerous sources.

(1) The terminal branches of the posterior rami of L. I, 2, and 3 cross the iliac
crest lateral to the sacro-spinalis, and may descend as far as the gluteal fold.

(2) The lateral branches of the ilio-hypogastric (L. i) and last thoracic nerves
(p. 240) cross the crest at the iliac tubercle and supply the skin of the adjoining
area. (3) Branches from the lateral cutaneous nerve of the thigh (L. 2 and 3)
pass backwards into the gluteal region. (4) The posterior cutaneous (small
sciatic) (S. i, 2, and 3) gives off recurrent branches, which ascend over the
lower border of the glutaeus maximus. (5) The skin near the middle line is
supplied by branches of S. i, 2, and 3 (Fig. 124).

Referred pain in the region of the buttock may occur in inflammatory
conditions of the lower part of the pleura (lateral cutaneous branch of T. 12)
or in irritative conditions of the bladder and rectum (posterior cutaneous
S. i, 2, and 3).

The Deep Fascia of the buttock is attached above to the
iliac crest. In its antero-superior part, where it covers the
glutaeus medius, it is a strong fibrous sheet, but it splits at the
upper border of the maximus into two much weaker layers,
which enclose the muscle. On the lateral aspect of the buttock
these two layers increase in strength, and having received the

THE GLUTEAL REGION 415

insertion of the greater part of the glutseus maximus, they re-
unite to form the strong ilio-tibial tract (p. 401).

The Glutaeus Maximus passes distally and laterally from
the posterior part of the iliac crest and the dorsum of the sacrum
to its insertion into the deep fascia and the gluteal tuberosity
of the femur. It is supplied by the inferior gluteal nerve (L. 5,
S. i and 2) and acts as an extensor, abductor, and lateral rotator
of the thigh. Owing to the great bulk of the muscle,, it is ex-
tremely difficult to determine fluctuation under cover of it.
The fasciculi of which it is made up are very coarse and can
readily be separated without damage. They run distally and
laterally, and incisions into the buttock are therefore made in
the same direction. In flexion of the thigh the posterior border
of the greater trochanter passes backwards beneath the upper
border of the glutseus maximus when the muscle is well developed.
The movement of medial rotation at once disengages the tro-
chanter, and the muscle slips off with an audible sound. The
condition, which is termed " snapping-hip," may be produced
voluntarily, and it was formerly thought to be due to a partial
subluxation at the joint. A layer of fat underlies the glutseus
maximus, and it may be the site of cellulitic infection following
intra-pelvic or ischio-rectal abscesses. The infection spreads
through the greater or lesser sciatic foramen, and it penetrates
the parietal pelvic fascia, which closes the foramina, by tracking
along the gluteal and the internal pudendal vessels (p. 417).
A large and constant bursa intervenes between the muscle and
the ischial tuberosity, and when inflamed gives rise to a painful
swelling. Such a bursitis requires to be differentiated from a
gumma and from a cold abscess (p. 522), which may both occur
in this situation.

Two other bursce are found near the insertion of the muscle,
one between its fascial insertion and the greater trochanter (p.
433) and the other between its tendon and the vastus lateralis.
They are both liable to tuberculous synovitis, and the resulting
cold abscess may spread (i) distally along the lateral surface of
the thigh under the fascia lata or (2) backwards and distally
under the glutseus maximus to point in the gluteal fold.

These bursae are frequently infected with tuberculous disease
and may be approached, by a U-shaped incision. The anterior
limb of the incision lies behind the posterior border of the
tensor fasciae latae, and the posterior limb divides the proximal
part of the insertion of the glutseus maximus. The transverse

4i6 THE INFERIOR EXTREMITY

part of the incision lies distal to the greater trochanter. Free
exposure is necessary, as the bursae when diseased may possess
extensive prolongations.

The glutaeus maximus covers most of the dorsum ilii and
the muscles, to which it gives origin, and both the sacro-tuberous
and the sacro-spinous (greater and lesser sacro-sciatic) ligaments.
In addition, it covers both the greater and lesser sciatic foramina
and the vessels and nerves which they transmit (Fig. 123).

The Piriformis (p. 355) emerges from the greater sciatic foramen, and,
as it passes laterally to the apex of the greater trochanter, it lies on the postero-
superior aspect of the capsule of the hip-joint. It abducts the thigh, and
receives its nerve-supply from S. i and 2.

The Glutaeus Medius is exposed above the upper border of the maximus,
but its posterior part is covered over by that muscle. It arises from the dorsum
ilii, and is inserted into an oblique ridge which runs forwards and distally
across the lateral aspect of the greater trochanter. The lower or posterior
border of the medius lies along the upper border of the piriformis.

The Glutaeus Minimus arises from the dorsum ilii, under cover of the
medius. As it passes to its insertion on the anterior aspect of the greater
trochanter, the muscle is closely related to the superior aspect of the capsule
of the hip-joint.

Both the glutaeus medius and minimus act as powerful abductors of the
thigh, but, in addition, their anterior fibres, which lie deep to the tensor
fasciae latas, assist in medial rotation. The nerve-supply to both muscles is
derived from the superior gluteal (L. 4 and 5, S. i).

The Superior Gluteal Artery, a branch of the hypogastric
(p. 369), enters the buttock through the greater sciatic foramen
between the adjoining borders of the piriformis and the glutseus
medius. It possesses a short trunk, which divides into a super-
ficial and a deep division. The former enters the maximus and
the latter breaks up into upper and lower branches, which pass
laterally between the medius and the minimus.

The upper branch terminates in the region of the anterior
superior iliac spine, where it anastomoses with the superficial
and deep circumflex iliac arteries (p. 253) and the ascending
branch of the lateral circumflex. This anastomosis constitutes
a connection between the hypogastric (internal iliac) and the
external iliac trunks (p. 408).

The superior gluteal artery may require to be ligated either
for aneurism or following stab wounds in the buttock. The
incision is made parallel to the fibres of the glutseus maximus,
and its centre lies at the junction of the upper and middle thirds
of the line joining the posterior superior iliac spine to the greater
trochanter. Owing to the depth at which the vessel lies and
the shortness of its main trunk, the incision should be a fairly
large one.

THE GLUTEAL REGION

417

The Superior Gluteal Nerve (L. 4, 5, S. i) accompanies the
artery, and supplies the glutaeus medius and minimus and the
tensor fasciae latae.

Several important structures leave the pelvis through the
greater sciatic foramen at the lower border of the piriformis.
They include (i) the sciatic nerve, (2) the posterior cutaneous
(small sciatic) nerve of the thigh, (3) the pudendal nerve, (4)

Superior gluteal artery
Superficial division i

Superior branch of deep division
Inferior branch of deep division

Inferior
gluteal n.
Internal
pudendal a. "~
Nerve to obtu-
rator internus •"

Sacro-tuberous
ligament

Tuber ischii

Biceps femoris
Semitendinosus

Glutaeus'minimus

Tensor fasciae latae

Glutaeus medius
Sciatic n.
Superior gemellus

irator internus tendon

Inferior gemellus
Ascending branch of
medial circumflex a.

Greater trochanter

Quadratus femoris
Posterior cutaneous n. of thigh
Insertion of glutaeus maximus

FIG. 123. — The Gluteal Region. The glutaeus maximus has been divided, and
the glutaeus medius has been removed from its origin and turned down.

the nerve to obturator internus, (5) the inferior gluteal nerve,
(6) the inferior gluteal (sciatic) vessels, and (7) the internal
pudendal vessels.

The pudendal nerve, internal pudendal vessels, and the
nerve to obturator internus cross the spine of the ischium and
pass through the lesser sciatic foramen to enter the ischio-rectal
fossa (p. 373). The vessels may be injured in stab wounds, and
can be exposed by an incision parallel to the fibres of the glutaeus
maximus, and cutting the line joining the posterior superior

27

418 THE INFERIOR EXTREMITY

iliac spine to the ischial tuberosity at the junction of its lower
and middle thirds.

The Sciatic Nerve (L. 4, 5, S. i, 2, 3) emerges below the
piriformis and passes distally, lying successively on the ischium,
the obturator internus and gemelli, and the quadratus femoris.
At the lower border of the quadratus it passes on to the posterior
surface of the adductor magnus, and is crossed superficially by
the long head of the biceps femoris; which is running distally
and laterally (Fig. 123).

In intractable cases of sciatica the nerve may be stretched
by open operation. The incision is carried vertically along the
thigh,, from the mid-point of the line joining the ischial tuber-
osity to the greater trochanter. After division of the skin and
fasciae, the lower border of the glutseus maximus and the biceps
tendon, which runs distally and laterally, are exposed. The
finger is passed into the angle between the two in a medial
direction, and the nerve is hooked up from under cover of the
biceps.

The Inferior Gluteal (Sciatic) Artery appears at the lower
border of the piriformis and at once breaks up into numerous
branches. It can be exposed by the incision already described
for the ligature of the internal pudendal artery (p. 417).

The crucial anastomosis occurs in the region of the quadrate
tubercle. Branches of the inferior and superior gluteal arteries,
which both arise from the hypogastric (internal iliac), anastomose
with branches of the medial and lateral circumflex arteries and
the first perforating, which arise from the profunda femoris.
In this way an important connection is formed between the
external iliac and the hypogastric trunks, and it is capable of
re-establishing the circulation in the lower limb, when the
external iliac is ligatured or when the femoral artery is tied
proximal to the origin of its profunda branch (p. 407).

The Posterior Cutaneous (Small Sciatic) Nerve of the
thigh (S. i, 2, and 3) runs distally, under cover of the glutseus
maximus and on the surface of the sciatic nerve. At the lower
border of the maximus the nerve crosses the biceps superficially,
and continues its course through the thigh immediately under
the deep fascia and in the middle line of the limb. It gives off
twigs to supply the skin of the buttock and of the posterior
and medial aspects of the thigh (Fig. 124).

Hernias may escape from the pelvis through the greater
sciatic foramen and appear at the upper or lower border of the

THE GLUTEAL REGION

419

as superior or inferior gluteal

Plit.^

yilfb^

piriformis. They are known
hernia. The former variety
is the less uncommon, and
it occurs more often in the
female and on the right side
of the body. The neck of
the sac lies in the fossa
ovarica (p. 393) in the angle
between the obturator and
the hypogastric arteries.
If the hernia becomes
strangulated, the constric-
tion at the neck should be
divided in a downward and
lateral direction, parallel to
the fibres of the piriformis.

The tendon of the obturator
interims (p. 355) leaves the pelvis
through the lesser sciatic foramen
and passes laterally to the greater
trochanter. The superior and
inferior gemelli are attached to
its upper and lower margins.
This tricipital tendon, which
abducts the thigh and rotates
it laterally, is closely related to
the posterior aspect of the cap-
sule of the hip-joint. The ob-
turator internus is supplied by
a special branch from the sacral
plexus (L. 5, S. i, 2).

The quadratus femoris is
placed at a slightly lower level.
Its fibres are practically horizon-
tal and extend from the ischial
tuberosity to the quadrate tub-
ercle on the intertrochanteric
crest (posterior intertrochanteric
line), so that the muscle acts as
a lateral rotator and also as an
adductor. It receives a special
branch from the sacral plexus
(L. 4, 5, S. i).

The Hip-Joint is

formed by the articulation FlGp ^4. -The Cutaneous Nerves on the

Posterior Aspect of the Lower Limb,
of the rounded head of the

femur with the cup-shaped acetabulum on the lateral aspect
of the hip-bone. The ilium, ischium, and pubis all share in

27 a

Lumbar nerves

Cutaneous branches

of the 1 2th thoracic

and ilio-hypogastric

nerves

Sacral nerves

Perforating
cutaneous

Branches from

posterior cutaneous -

nerve of the thigh

Lateral cutaneous

nerve of the thigh

Long perineal

Posterior cutaneous
nerve of the thigh

Medial cutaneous
nerve of the thigh

Lateral cutaneous
nerve of the thigh

Medial cutaneous
nerve of the thigh

Anastomotic peroneal
nerve

Posterior cutaneous
nerve of the thigh

Medial cutaneous nerve
of the calf (O.T. ramus —
communicans tibialis)

Nervus suralis
(O.T. short saphenous)

Medial calcanean branch

420 THE INFERIOR EXTREMITY

the formation of the acetabulum, and at birth they are separated
from one another by a triradiate bar of cartilage. Secondary
centres of ossification appear in this cartilage about the twelfth
year, and the acetabulum is completely ossified by the sixteenth
or seventeenth year (Fig. 126).

The articular cartilage forms a broad strip round the
acetabulum near its circumference, but the floor of the cavity
and the acetabular (cotyloid) notch are non-articular.

At birth the proximal end of the femur is entirely cartil-
aginous. The neck of the femur is ossified by a proximal
extension from the diaphysis, and, as it forms, it divides the
cartilaginous extremity into two parts, which it separates from
one another. The more proximal of these forms the head. A
centre of ossification appears in it during the first year, and it
unites with the neck during the twentieth year. The more
distal forms the greater trochanter, which begins to ossify in
the second year and joins the shaft at 19. The secondary
centre for the lesser trochanter, which unites with the shaft
at 1 8, does not appear till the eighth to the twelfth year.

The articular head of the femur forms rather more than
half a sphere. A little below and behind its centre there is a
non-articular depression for the attachment of the ligamentum
teres.

The Labrum Glenoidale (cotyloid ligament) is a strong
fibre-cartilaginous ring attached to the circumference of the
acetabulum, and serving both to deepen its cavity and to reduce
the diameter of its inlet. It is accurately fitted round the head
of the femur, and even after the joint has been opened it is
not easy to pull the head of the femur out of the acetabulum.

The Transverse Ligament bridges across the acetabular
notch, and completes the circumference of the acetabulum.

The Capsule of the hip- joint is of great strength. Proximally,
it is attached to the bony circumference of the acetabulum,
the labrum glenoidale, and the transverse ligament (Fig. 125).
Distally, it is attached to the neck of the femur ; anteriorly,
this attachment is along the intertrochanteric line; but pos-
teriorly, it crosses the middle of the femoral neck — i.e. the whole
of the anterior surface and the medial half of the posterior
surface of the femoral neck lie within the capsule.

The capsule is strengthened by certain accessory ligaments.

i. The Ilio-Femoral Ligament is a well-marked thickening
of the anterior aspect of the capsule. It is attached proximally

THE HIP- JOINT 421

to the anterior inferior iliac spine, just below the origin of the
straight head of the rectus femoris. Distally it divides into two
parts, which are respectively attached to the upper and lower
portions of the intertrochanteric line.

The medial, longer limb of the ilio-femoral ligament sustains
the forward pressure of the femoral head when the body is in
the erect attitude, and prevents hyperextension of the joint.
The shorter, lateral limb prevents too great a degree of adduction
and lateral rotation, as these movements render it tense.

2. The Pubo-Capsular Ligament strengthens the infero-
medial part of the capsule. It becomes tense during the move-
ment of abduction.

3. The Ischio-Capsular Ligament is a much weaker band,
which is placed in relation to the posterior aspect of the capsule.
It helps to prevent too great a degree of medial rotation.

Although it is usually complete, the capsule is occasionally
interrupted by a communication between the joint cavity and
the bursa under the psoas major (p. 273). This opening lies
between the medial limb of the ilio-femoral and the pubo-
capsular ligament.

The ligamentum teres is intra-capsular but extra-synovial.
It is attached distally to the head of the femur and proximally
to the transverse ligament and the edges of the acetabular
notch. It is completely surrounded by a tube of synovial
membrane (Fig. 125).

The Synovial Membrane of the hip-joint covers the deep
surface of the capsule, and at the distal attachment of the
latter is reflected on to the femoral neck, where it is thrown
into numerous parallel ridges, known as the retinacula. At
the attachment of the capsule to the transverse ligament, the
synovial membrane forms a tube round the ligamentum teres
and also covers the pad of fat (Haversian gland) which occupies
the floor of the acetabulum (Fig. 125).

Spread of Tuberculous Disease in the Region of

the Hip-Joint. — Tuberculous disease in the region of the hip-
joint commences most frequently in the neck of the femur, near
its lower surface, and close to the epiphyseal cartilage of the
head of the bone. It is in the first place extra-synovial but
intra-capsular, and, on this account, infection of the hip-joint
occurs with great frequency. As the disease progresses it
reaches the surface of the bone, destroys the periosteum, and
invades the synovial membrane. These changes are usually

27 &

422

THE INFERIOR EXTREMITY

accompanied by a reactionary effusion within the joint. If
this effusion occurs early in the disease, adhesions may form
between the synovial membrane of the femoral neck and that
lining the capsule and delay the extension of the disease into the
joint. Such adhesions give rise to limitation of movement,

Labruni glenoidale

Head of femur

Acetabular pad

Capsule of hip-joint

Articular artery

Transverse acetabular
ligament

FIG. 125. — Oblique Section through Right Hip-Joint, showing the relation
of the Capsule to the Epiphysis of the Head of the Femur.

Light blue = articular cartilage. Green = periosteum.

Striped blue = ligaments. Red = synovial membrane.

which may be the first sign of the disease. In the absence
of adhesions, the disease rapidly becomes intra- synovial and
attacks the articular cartilage.

If the disease spreads across the neck it may actually separate
the head or render it so weak that a diastasis readily occurs.
Only very exceptionally does the disease perforate the epiphyseal
cartilage and invade the epiphysis from without the joint.

THE HIP-JOINT 423

Tuberculous disease may originate in any of the three com-
ponent parts of the acetabulum (p. 419); and in this case the
spread to the joint is prevented only by the articular cartilage,
i.e. no epiphysis intervenes between the joint cavity and the
tuberculous focus.

The diaphyseal side of the epiphysis for the greater trochanter
constitutes a third site for the occurrence of tuberculous disease
in this region. Spread may take place (a) down the shaft, as
an osteo-myelitis ; (b) along the neck, ultimately involving the
joint ; or (c) through the periosteum in front of or behind
the trochanter, giving rise to abscess and sinus formation.
Tuberculous abscesses in the region of the hip, however, much
more commonly have their origin within the joint.

When the disease becomes intra-synovial the pus eventually
perforates the capsule at its weakest points, which are found
(i) postero-laterally, and (2) anteriorly, between the ilio-femoral
and pubo-capsular ligaments.

1. After perforating the postero-lateral part of the capsule
the pus gravitates distally and backwards to point near the
gluteal fold, but it occasionally travels forwards deep to the
glutseus maximus and the tensor fasciae latse to point in the
interval between the latter muscle and the sartorius (p. 398).

2. The course taken by pus, after perforating the anterior
aspect of the capsule, is by no means constant, (a) If the joint
cavity communicates with the psoas bursa (p. 273) the pus
ascends within the bursa to the iliac fossa and the pelvis. It
may here be pointed out that a psoas abscess may infect the
bursa, and, spreading in the opposite direction, may involve
the hip-joint, (b) The pus may gravitate along the tendon of
the psoas major and then follow the course of the medial circum-
flex artery (p. 410). It reaches the dorsum above the upper
border of the adductor magnus and points in the gluteal fold.
(c) Sometimes, after following the psoas major tendon, the pus
passes laterally along the lateral circumflex artery and reaches
the surface in the gluteal fold or in the neighbourhood of the
greater trochanter. In the former case, the condition has to be
diagnosed from a tuberculous infection of the bursse underlying
the tendon of the glutseus maximus.

3. More rarely the pus perforates the inferior aspect of the
capsule, and at once comes into relation with the obturator
externus (p. 410). By following this muscle to its insertion the
pus again reaches the gluteal fold, but if it tracks in the opposite

27 c

424 THE INFERIOR EXTREMITY

direction it comes to the surface on the proximo-medial part
of the thigh.

Intra-Pelvic Spread. — When tuberculous disease originates
in the acetabulum, it may not only infect the joint but it may
spread inwards to the pelvis. The course taken by the pus in
the latter case depends on whether it pierces the pelvic wall
above or below the line of origin of the levator ani (Fig. 114).
In the former case the pus pierces the parietal pelvic fascia and
lies in the subperitoneal areolar tissue. It may track along the
rectum, or it may fill up the pelvis till it overflows through
the obturator foramen or escapes into the thigh behind the
inguinal ligament. When it pierces the pelvic wall below the
line of origin of the levator ani, the pus at once gains the ischio-
rectal fossa and gravitates downwards to point near the anus.

Owing to the possibility of intra-pelvic spread, digital
examination of the pelvis should be carried out per rectum in
every case of tuberculous disease of the hip-joint.

Aspiration of the Hip-Joint can be carried out by intro-
ducing an exploring needle upwards, backwards, and medially at
a point 2 to 2 1 inches distal to the anterior inferior iliac spine.
The instrument gains the interior of the joint by passing under
the lateral border of the rectus femoris and piercing the dis-
tended capsule.

The following lines and measurements are of value in the
examination of the region of the hip-joint.

The line joining the highest parts of the two greater tro-
chanters passes through the centres of the two acetabula. The
head of the femur lies behind the point of intersection of this
line and the produced lateral line of the abdomen.

Nelaton's line, which joins the anterior superior iliac spine
to the ischial tuberosity, passes through the highest part of the
greater trochanter. When the trochanter is found to lie above
or below that line some deformity of the neck of the femur
must be present. The difficulty of accurate localisation of the
ischial tuberosity minimises the value of this method of
examination.

Chiene demonstrated the symmetry or asymmetry of the
trochanters by comparing the line joining their highest points
with the line joining the anterior superior spines. This method
is of service when the deformity is unilateral, as the lines are
then no longer parallel, but it may fail to indicate a bilateral
deformity.

THE HIP- JOINT 425

Bryant's method involves the measurement of the vertical
distance between the highest point on the greater trochanter
and the horizontal plane passing through the anterior superior
iliac spines. This distance is normally .about two inches.
Asymmetry points to unilateral deformity and symmetrical
measurements, with marked deviation from the normal two
inches, to bilateral deformity.

A comparison of the length measurements of the two limbs
is of great value to the surgeon in relation to injury or disease
in the region of the hip. Before proceeding with the actual
measurements, it is very important to see that the pelvis is not
tilted to one side and to make certain that the patient's limbs
are both in exactly the same position. To discover any lateral
tilting of the pelvis, a line is drawn from the anterior superior
spine of the ilium at right angles to the linea alba, and this,
when produced, should pass through the anterior superior spine
of the other side.

Measurements should be taken from the anterior superior
spine to the distal margin of the medial condyle of the femur
and from that point to the medial malleolus, and these measure-
ments should be compared with those obtained on the opposite
limb. From this comparison any inequality of the two limbs
can be referred to the bone at fault, either the femur or the tibia
as the case may be, and this method is therefore of much greater
value than the direct measurement from the anterior superior
spine to the medial malleolus. When femoral shortening is
discovered, the deformity can be referred to the shaft or the neck
by comparing the measurements from the tips of the greater
trochanters to the distal borders of the lateral condyles. If
these are found to be equal, the deformity must be in the femoral
neck. Shortening of the femoral or tibial shaft may arise as a
result of infantile paralysis.

It is by no means unusual for the length measurements to
show trifling differences, and, unless this exceeds half an inch,
no stress should be laid on it.

The measurements are usually carried out with the patient
in the dorsal decubitus, and care must be taken to see that the
limbs have the same position relative to the trunk as they have
in the erect attitude. This precaution is essential, as the distance
between the anterior superior spine and the medial condyle is
definitely shorter in abduction than it is in adduction of the
thigh. Hence if the diseased limb is abducted, it is shortened,

426 THE INFERIOR EXTREMITY

and if the sound limb is adducted so as to be parallel to it, it is
lengthened proportionately. The difference between the length
measurements will, therefore,, be very considerable.

A convenient method of comparing the lengths of the lower
limbs can be used in children. The patient is placed on his
back; and care is taken to see that the limbs are symmetrically
disposed and that the pelvis is not tilted. With the knees
extended, the thighs are semi-flexed at the hips so that the
soles point upwards. The relative positions of the heels are
at once demonstrated.

Examination of the Hip-Joint and Proximal Ex-
tremity Of the Femur.— The patient should be completely
stripped and asked to walk if possible, as the gait may be of
assistance in determining the diagnosis. Any limitation of
active movement, the presence of a limp or lurch, and the way
in which the feet are placed on the ground should all be observed
with great care.

After this inspection the patient should be placed on his
back on a hard, firm surface. The bony prominences on each
side can then be carefully marked, and while this is being done
palpation and comparison of the trochanters may be carried
out and the position of the femoral head may be determined.
The measurements of both limbs are next taken and the various
lines (p. 424) may be utilised.

Lastly, the extent and nature of passive movements must
be examined. These movements, which comprise flexion,
extension, abduction, adduction, circumduction, and rotation
are first carried out on the healthy limb in order to test their
normal extent and to gain the confidence of the patient. Next
the movement of hyperextension is tested, with the patient in
the prone position. The pelvis is fixed by a hand placed on the
sacrum ; and the other hand, placed under the thigh, hyper-
extends the limb by lifting it from the table. Differences in
the extent of symmetrically arranged passive movements, with
or even without differences in length measurements, are most
valuable in diagnosis.

The use of radiograms has made the diagnosis of disease or
injury in the region of the hip-joint much more certain.

Function of the Hip -Joint. — In contradistinction to the
shoulder-joint, where free mobility is the first essential, the
chief characteristic of the hip-joint is its stability. Consequently,
in the treatment of pathological conditions of the joint, the chief

THE HIP-JOINT 427

aim of the surgeon is to obtain a stable joint. If a movable
joint can be obtained at the same time, the result will be so
much the better, but mobility without stability is of no value.

The weight of the trunk is transmitted to the femoral heads
through the upper parts of the acetabula, and thence is trans-
mitted down the limbs to the ground.

In order to increase the power and mobility of the lower
limb and to distribute the weight of the body over a wider base,
the neck of the femur is inclined to the shaft at an angle which
varies from 160° in the child to 110° in the adult, i.e. with the
constant increase in body-weight the angle deviates more and
more from 160°.

Abnormal alterations of the angle may seriously interfere
with the mobility of the hip-joint. In cases of early extensive
infantile paralysis of the lower limb, and in congenital dislocation
of the hip, the angle remains of the infantile type, since the
head and neck of the femur are not used to support their share
of the body-weight. This condition is known as coxa valga.

In constitutional diseases, such as rickets, and following
injuries to the neck of the femur during infancy, the body-
weight acting on softened bone produces an abnormal decrease
of the angle, which in some cases may be reduced to 45°. This
condition is termed coxa vara.

Abduction of the thigh is markedly limited in coxa vara,
as the greater trochanter impinges too soon on the ilium. In
coxa valga, on the other hand, abduction is a very free movement,
but adduction is correspondingly limited.

Injuries of the Neck of the Femur.— In the infant, the
cartilaginous proximal extremity of the femur, which includes
both the head and the neck, may be fractured. The injury
often occurs in the following way. When an infant, held in
the nurse's arms, throws itself backwards, the weight of its body
stretches the strong ilio-femoral ligament across the anterior
surface of the head of the femur. If the child's limbs
were not held by the nurse the pull of the body-weight on the
ligament would flex the thigh and relieve the strain, but as
the limbs are firmly held, the cartilaginous neck of the femur
gives way, since the ilio-femoral ligament is too strong to yield.

In the child, injury in this region may result in a green-stick
fracture, as the cartilaginous neck is undergoing ossification.
Radiograms have shown that this accident is by no means rare,
and it is probably one of the most frequent causes of coxa vara.

428 THE INFERIOR EXTREMITY

At school age, injury in this region may take the form of a
separation of the epiphysis of the femoral head. The correct
diagnosis of this condition is extremely important, as unless
proper treatment is carried out the epiphysis unites in a faulty
position, and subsequent limitation of movement results. After
union has occurred no manipulations can separate the fragment
for the purpose of reposition in correct alignment.

This injury is usually caused by violent rotatory movements
of the trunk while the body-weight is being supported on the
femur. When examined the limb is found to be powerless,
and there is marked eversion together with some slight shorten-
ing. The diagnosis should be confirmed by the X-rays.

Dislocations of the Hip-Joint may be (i) Congenital,
(2) Traumatic, or (3) Pathological.

(i) CONGENITAL DISLOCATION of the hip-joint occurs more
frequently in females than in males, and this incidence is possibly
due to the fact that in the female the acetabulum looks more
directly to the lateral side.

The head of the femur is situated on the dorsum ilii just
lateral to the anterior inferior spine, and is enclosed within
the untorn but greatly stretched articular capsule. In these
cases it is doubtful whether the head of the bone has ever occupied
the acetabulum, which is usually rudimentary. The capsule
possesses its normal attachments, but, owing to the stretching
to which it has been subjected, it resembles an hour-glass in
shape. When the child begins to walk, the proximal part of
the capsule has to transmit the body-weight to the femur, and
the condition becomes more exaggerated. The child walks
with a heavy downward lurch to the affected side, and the
muscles connecting the trunk to the thigh become greatly
shortened. The longer the condition is allowed to remain un-
treated, the more difficult will it be to carry out remedial
measures and the poorer the subsequent result.

Owing to the shortening of the muscles it may be difficult
to place the head of the femur in the acetabulum, but the
reduction does not involve the passage of the head through
a tear in the capsule, as in the case of a traumatic dislocation.
Since the Socket of the acetabulum may be undeveloped or
rudimentary, it is a matter of great difficulty to retain the head
of the femur in place after the reduction has been effected.
Further, the proximal part of the hour-glass shaped capsule
becomes nipped between the two articular surfaces.

THE HIP-JOINT

429

After the muscles have been thoroughly stretched, torn, or
divided by tenotomy, the head is placed in the acetabulum,
and the limb is fixed in plaster of Paris with the thigh abducted

FIG. 126. — Congenital Dislocation of the Hip-Joint in a Child aged five.
The head of the femur is not in the acetabulum, and the angle of the
neck is greater than normal. The femur is medially rotated. Observe
the epiphyses for the head of the femur and the greater trochanter. The
dark area passing through the acetabulum corresponds to two of the
limbs of the triradiate bar of cartilage.

to a right angle and laterally rotated — the " frog " position.
When this is done, the head of the femur can be felt anterior
to the acetabulum, where a distinct depression existed prior

430 THE INFERIOR EXTREMITY

to the manipulations. Subsequently, the plaster case is renewed
every three months, and on each occasion the limb is slightly
lowered and the amount of lateral rotation similarly decreased.
At the end of fourteen to twenty months the limbs should be in
a normal position and walking may be resumed.

(2) TRAUMATIC DISLOCATION of the hip is comparatively rare,
owing to the fact that the arrangement of the bones renders
the joint osseously strong. For the same reason, fractures are
relatively much more frequent.

In " regular dislocations " the ilio -femoral ligament is not
damaged or only its lateral limb is torn. When both limbs
of the ilio-femoral ligament are injured, or when portions of the
head of the femur or the acetabulum are fractured, the disloca-
tion is termed " irregular."

(a) Regular Dislocations. — The tear in the capsule is usually
inferior or postero -inferior, and the position which the head of
the femur takes up, after passing through it, depends partly
on muscular action and partly on the position of the limb
relative to the pelvis at the time of the accident. If the injury
is produced by a heavy weight falling on the sacrum when the
subject is in a stooping attitude with the lower limbs flexed
and rotated medially — the common position at the time of the
accident — the head of the femur passes posteriorly on to the
dorsum ilii. The rarer anterior dislocation occurs when the
limbs are abducted and rotated laterally.

1. The Sub-acetabular Dislocation is the first stage in all
varieties of regular dislocations, but the head seldom remains
in this position. On leaving the lower part of the capsule the
femoral head at once encounters the obturator externus, and it
may pass backwards, either above or below the tendon, or it
may pass forwards on to the surface of the muscle.

2. Dorsal Dislocation. — In the commonest form of this
variety, the femoral head passes backwards above the obturator
externus and then ascends, either tearing through or passing
in front of the obturator internus and the piriformis. It comes
to rest on the dorsum ilii between the piriformis and the glutseus
medius. Owing to the slope of the ilium, the articular head is
directed backwards and the greater trochanter forwards, i.e.
the limb is inverted, and it is maintained in this position by
the tension of the lateral limb of the ilio-femoral ligament. In
addition, the thigh is slightly flexed.

The flexion, medial rotation, shortening, and constrained

THE HIP- JOINT 431

attitude of the limb are characteristic, and serve to distinguish
this dislocation from other injuries.

More rarely, the neck of the femur becomes caught beneath
the obturator internus. The attitude of the limb resembles
that found in the variety just described, but the flexion and
rotation are more exaggerated. The head may injure the
sciatic nerve, which is stretched across it in the interval between
the inferior gemellus and the quadratus femoris.

The lateral limb of the ilio-femoral ligament is the important
agent in maintaining medial rotation, and when it is torn the
limb adopts an everted position (Bigelow).

3. Anterior Dislocation. — From the subacetabular stage, the
head may pass forwards and medially in front of the obturator
externus. The greater trochanter is directed backwards and
laterally, and the limb is kept abducted, extended, and laterally
rotated, the eversion being produced and maintained by the ilio-
femoral ligament. This variety is sometimes referred to as
the " thyroid dislocation."

The head may pass still further in an upward direction,
injuring the pectineus and adductor muscles, and it subsequently
comes to rest somewhere between the anterior inferior iliac spine
and the pubic tubercle, constituting the pubic, subspinous, and
pectineal varieties.

(b) Irregular Dislocations are usually caused by extreme
violence and the position taken up by the head is very inconstant,
but it often tends to pass downwards and backwards towards
the lesser sciatic foramen ; the limb is usually everted (Bigelow).
When the ilio-femoral ligament is ruptured, the femoral head
may pass backwards below the obturator externus tendon, which
is consequently stretched across the upper aspect of the neck.
The head then assumes a position in the neighbourhood of the
ischial tuberosity.

In the Reduction of a Dislocation of the Hip the head of
the bone is made to retrace its course through the tear in the
capsule.

i. In the posterior group the limb is kept flexed and adducted
by the tension of the ilio-femoral ligament, which must first be
relaxed by flexing and adducting the thigh still further. As the
thigh is carried upwards and medially, the head of the femur
passes downwards and laterally and approaches the level of the
tear in the capsule, but it is still posterior to the acetabulum.
The thigh is next circumducted and laterally rotated. This

432 THE INFERIOR EXTREMITY

movement renders the relaxed ilio-femoral ligament tense,, and
it may be used as the fulcrum of a lever which has the femoral
shaft for its long arm and the neck for its short arm. The
movement of lateral rotation levers the head forwards over
the posterior margin of the acetabulum, and, by completing
the circumduction and finally extending the limb, the head is
made to travel medially and upwards into its socket.

2. In the anterior group the method followed is much the
same as the foregoing, but the movements are carried out in
the reverse direction. The tense ilio-femoral ligament maintains
the femur in a position of extension, abduction, and lateral
rotation, and it must be relaxed by flexing the abducted thigh
in order to release the head from its pubic position. As the
thigh is elevated, the head descends to the level of the acetabulum,
and it is made to travel laterally by circumducting the fully
flexed thigh in a medial direction. Finally, the limb is extended,
and this movement carries the head forwards and medially into
the acetabulum.

(3) PATHOLOGICAL DISLOCATIONS of the hip-joint are preceded
by atrophy of the surrounding muscles from disuse and by soften-
ing of the articular capsule. Sometimes, as in advanced tubercle,
the acetabular margin or the head of the femur is much eroded.
In these cases the joint cavity is often distended by fluid or
granulations, and the thigh is maintained in the position of semi-
flexion, since the capacity of the hip -joint is greatest in that
attitude. When the limb is adducted, the head of the bone
gradually perforates the weakened capsule, but this causes so
little pain that it may escape notice until the general condition
has been recovered from.

It should be pointed out that pathological dislocations of
the hip-joint are always posterior, owing to the position of the
limb at the time of their occurrence.

The Surgical Approach to the Hip-Joint is planned
so as to give good exposure while doing little damage. The
operation of excision yields excellent results, sometimes even
in cases of advanced tuberculous disease. As a rule a posterior
dislocation is present, or there may have been erosion of the
neck of the femur, so that the head lies loose in the acetabulum.
On this account the joint is best approached from behind —
Kocher's postero-lateral route.

The upper half of the incision corresponds to the lower
two-thirds of the line joining the posterior superior iliac spine

THE HIP- JOINT 433

to the greater trochanter, and is in the direction of the fibres
of the glutseus maximus. In its lower half the incision is carried
vertically across the greater trochanter, splitting the ilio-tibial
tract. The wound is deepened through the, glutseus maximus,
above and below, and it opens into the bursa between the
tendon of the muscle and the greater trochanter. A large
angular flap, consisting of skin, fasciae, and the glutseus maximus,
can now be turned medially, and this exposes the posterior
border of the glutaeus medius and the piriformis. When a
posterior dislocation has occurred, the head of the femur is
found between these two muscles.

Since the operation is usually performed in children, the
epiphysis of the greater trochanter is still partly cartilaginous,
and this simplifies the next step, which consists in turning
forwards the insertion of the glutaeus medius. The oblique
insertion of the muscle (p. 416) is removed along with its peri-
osteum and a thin layer of cartilage, and the insertions of the
obturator internus and piriformis are treated in a similar way,
but they are turned backwards. When these steps have been
carried out, the trochanteric fossa, the neck of the femur, the
head, if present, and the remains of the dorsal aspect of the
capsule are all exposed.

The capsule is then split in its long axis, and the neck of the
femur is divided at its distal end and removed. The condition
of the acetabulum and the synovial membrane can then be
explored satisfactorily and dealt with. The greater trochanter
is brought to the surface and is trimmed to fit the acetabulum.
It is then implanted into the latter at an angle corresponding
to that of the original neck, and, in order that this position may
be maintained, an assistant keeps the limb in the required
degree of abduction until the operation is completed and the
special abduction splint can be applied. The remains of the
capsule and the tendons which were removed are now stitched
together over the trochanter, and the split glutseus maximus is
sutured. A gauze drain may be passed down to the neighbour-
hood of the joint, but no tube is necessary, because, as the
acetabulum is now occupied by the trochanter, there is no space
to drain.

This operation aims at obtaining an ankylosed and therefore
a stable joint, which is the first essential. When the limb has
been kept in a plaster case for a year and firm bony union has
occurred, the child is allowed to walk. In order to bring the

28

434 THE INFERIOR EXTREMITY

limbs together, the pelvis is depressed upon the affected side
when the abducted limb is placed upon the ground, and the
acetabulum looks almost directly downwards like an inverted
cup, thus ensuring stability. Adduction of the sound limb is
necessary, and the centre of gravity, which is upset by the tilting
of the pelvis, is restored by a compensatory lumbo-thoracic
scoliosis. The sole of the boot on the sound limb may be
thickened to make certain that the pelvis will be sufficiently
tilted, and later, as the ankylosed joint grows stronger, the
thickening may be gradually reduced. Finally, the sole of the
boot on the affected limb may be gradually thickened, in the
hope that the tilting of the pelvis will give way to a gradual
angulation in the proximal part of the femoral shaft.

When excision of the hip-joint is performed in those cases
in which the limb is markedly adducted, a preliminary tenotomy
of the shortened adductors is necessary. This enables the
limb to be abducted, and allows the trochanter to be placed
and kept in the acetabulum. Further, as the aim is to obtain
an ankylosed joint with the limb abducted, the adductors will
no longer be required. A vertical incision is made along the
tendon of the adductor longus, and that muscle is exposed
together with the gracilis at its medial border. Both are cut
across with scissors, and their ends retract, exposing the adductor
brevis and the anterior division of the obturator nerve. Both
these structures are divided, and the adductor magnus, with the
posterior branch of the obturator nerve on its surface, is brought
into view. The nerve is cut through and the greater part of
the muscle is divided. The wound is then closed, and the
excision is performed in the manner already described.

The Anterior Route for Excision of the Hip-Joint
is carried out through a vertical incision, made dis tally from
the anterior superior iliac spine, and the skin, superficial and
deep fasciae are divided. The sartorius is exposed at the medial
side of the wound, running distally and medially (p. 398), while
laterally the anterior margin of the tensor fasciae latse is found.
The wound is deepened in the V-shaped interval between these
muscles, until the rectus femoris is brought into view. This
muscle is retracted medially, and at this stage the ascending
branch of the lateral circumflex (p. 409) may be divided. The
anterior aspect of the capsule is then exposed.

This route may be adopted in tuberculous disease of the hip-
joint when there is an abscess opening on the anterior aspect of

THE HIP-JOINT 435

the limb, provided that a posterior dislocation is not present.
It may also be utilised \yhen operative interference is necessary
in congenital dislocations.

Attitude of the Lower Limb in Disease of the
Hip-Joint. — Semi-flexion is the position of rest assumed in all
joints. Consequently this is the position which the limb first
takes up when there is effusion into the hip- joint, since in this
attitude the tense ilio-femoral ligament is relaxed.

The commencement of tuberculous disease in the femoral
neck, associated with a simple effusion into the joint, is sufficient
to cause flexion and slight lateral rotation. When the synovial
membrane is attacked the thigh becomes abducted in addition.
As a result of the position assumed by the limb, the pelvis is
tilted downwards to the affected side to enable the foot to reach
the ground, and a compensatory adduction of the sound limb
becomes necessary to restore the parallelism of the two limbs.
Scoliosis of the lumbo-thoracic region restores the centre of
gravity (p. 434). As a result there is apparent lengthening of
the diseased limb, but the real condition is readily discovered
by measurements and the examination of the relative positions
of the anterior superior iliac spines.

As the disease progresses the existing flexion increases, and
the pelvis becomes tilted forwards to accommodate itself to the
altering conditions. To prevent the centre of gravity from being
thrown too far forwards the lumbar curve is greatly exaggerated,
constituting the condition of lordosis. At the same time the
sound limb must also take up a flexed position. The inter-
vertebral joints of the lumbo-sacral region acquire a greater
degree of mobility, and passive movements carried out upon
the diseased joint are transferred to them at once owing to the
rigidity and spasm of the surrounding muscles. Under anaesthesia
and during sleep the muscles become relaxed. In the latter
case this allows some movement between the diseased articular
surfaces, and the consequent irritation of the exposed nerve-
endings produces the " starting pains."

In order to reduce the amount of tilting of the pelvis, com-
pensation is sometimes gained by flexing the knee and extending
the ankle on the diseased side, so that the patient walks on the
balls of the toes.

The condition in which the limb is flexed, adducted, and
rotated medially is commonly found in tuberculous disease, and
it is often described as a later stage of the preceding condition.

436 THE INFERIOR EXTREMITY

It seems possible, however, that in these cases adduction is
present from the beginning, and that the attitude is due to a
reflex stimulation of the adductor muscles by the obturator
nerve, which helps to supply the joint (p. 411). With the thigh
flexed and adducted, lateral rotation would result in the tighten-
ing of the ilio-femoral ligament. The limb, therefore, becomes
rotated medially, and in this position the ligament is slackened
to its furthest extent. As a result of the adduction of the
diseased limb, the sound limb is abducted to maintain their
parallelism, and the pelvis is depressed to the sound side. This
necessitates a compensatory scoliosis, and the centre of gravity
takes up a position over the healthy limb.

In this attitude the diseased limb appears to be shorter than
its fellow. If measurements show that the shortening is real,
then either a pathological dislocation has occurred or the femoral
neck has been eroded. In both cases the upper border of the
greater trochanter is found above Nelaton's line (p. 424).

When extension by weight and pulley is used to undo the
deformity of flexion and abduction in tuberculous disease of
the hip-joint, the force is primarily applied in the long axis of
the deformed limb. As the deformity is slowly overcome the
pulley is gradually lowered and carried medially. To prevent
the extending force from simply increasing the downward tilt
of the pelvis on the affected side, a greater weight must be applied
to the sound limb. A perineal band extending to the top corner
of the bed on the diseased side acts as a fulcrum over which the
two weights pull, and the greater weight, being on the sound
limb, tends to restore the pelvis to its normal position and, at
the same time, to reduce the abduction of the affected limb.

When the deformity consists of flexion and adduction,
weights only need to be applied to the affected limb, as the
pelvis is tilted upwards on that side. A perineal band to the
top corner of the bed on the sound side is used to provide a
fulcrum, and the normal position of the pelvis is gradually
restored.

Surgical Approach to the Neck of the Femur.— The
region of the greater trochanter and the neck of the femur may
be approached either by a vertical incision over the trochanter
or by a U-shaped incision (p. 415).

The vertical incision is carried through the fascial insertion
of the glutseus maximus, exposing (i) the insertion of the glutseus
medius, proximally, (2) the postero-distal part of the trochanter,

THE FEMUR 437

and (3) the tendinous origin of the vastus lateralis, in the distal
part of the wound. Plastic operations on the neck of the femur
(Jones ; Murphy) and sub-trochanteric osteotomy may be carried
out by this route. The latter operation is performed when the
hip-joint is ankylosed in bad position and may consist of the
removal of a wedge-shaped portion or in division of the femur.
When flexion constitutes the more marked deformity, the
base of the wedge is posterior, but, when adduction is more
pronounced, the base is on the lateral aspect.

After the femur has been exposed by cutting through the
vastus lateralis, the periosteum is divided transversely, distal
to the greater trochanter, and the cut edges are elevated from
the bone. A wedge of bone may then be removed from the
required site and the periosteum is stitched together again.
When the wound has been closed the limb is placed in the
best position obtainable, and is kept fixed by the necessary
splints.

The Shaft of the Femur is so obscured by its muscular
covering that actual palpation is impossible. Thickening of
the shaft may be determined by grasping the thigh firmly from
in front so that the finger tips are inserted along the line of the
medial (or lateral) intermuscular septum, while the thumb is
inserted along the line of the lateral (or medial) intermuscular
septum. In comparing the circumferential measurements of
the two limbs it must be remembered that thickening of the
femoral shaft may be accompanied by atrophy of the surrounding
muscles, so that, although the one limb is normal and the other
abnormal, the measurements obtained may be practically
equal.

In osteo-myelitis, incisions to expose the femoral diaphysis
are made along the line of the lateral intermuscular septum, as
few important structures intervene between the surface and
the bone in this situation. The incision splits the ilio-tibial
tract and exposes the vastus lateralis. When the wound is
deepened through this muscle, the vastus intermedius (crureus)
is exposed and may be elevated from the lateral surface of the
femur. If the incision is extended over the distal part of the
diaphysis, the vastus lateralis is retracted forwards from the
intermuscular septum, which is drawn backwards together with
the short head of the biceps. The distal part of the lateral
surface of the femur is thus exposed, and the anastomosis
between the descending branch of the lateral circumflex and

438 THE INFERIOR EXTREMITY

the lateral superior genicular artery (p. 445) may be seen on
the bone.

The distal part of this incision may be employed in performing
cuneiform osteotomy for genu varum (p. 465).

In Operations for Genu Valgum the distal portion of
the shaft is approached from the medial side. The centre of
the incision lies one finger's breadth anterior and one finger's
breadth proximal to the adductor tubercle, and the wound is
directed distally and forwards, parallel to the fibres of the
vastus medialis. It thus lies anterior to the articular branch
of the arteria genu suprema (anastomotica) and proximal to the
distal epiphyseal cartilage, which corresponds in level to a
horizontal line drawn through the adductor tubercle. After
division of the skin and fascise, the vastus medialis is split
and the bone is exposed. The periosteum is incised vertically
for about one inch, and transverse cuts are made at each end of
this incision so that two small periosteal flaps may be elevated.
Cuneiform osteotomy or partial division of the femur may then
be carried out.

Fractures of the Proximal Extremity of the
Femur. — The neck of the femur may be fractured (i) at its
proximal end, close to the head, or (2) at its distal end, close to
the greater trochanter.

i. This fracture is common in elderly people and is generally
due to indirect violence, but the force required is not great
owing to the rarefied condition of the bone. In healthy adults
the injury may result from a fall on the greater trochanter and,
in this case, the neck may be impacted into the cancellous tissue
of the head.

The fracture is entirely intra-capsular and the fragments may
be completely separated or they may be retained in more or less
accurate apposition by the periosteum and synovial membrane
(Fig. 125). In old people non-union of the fragments is very
common. It is due partly to the reduced vitality, but especially
to the fact that the blood-supply to the head from the neck is
damaged and the supply via the ligamentum teres (Fig. 125) is
insufficient.

If the neck is impacted into the head the amount of
shortening is usually small and special treatment is not called
for. When shortening and eversion are pronounced, active
measures must be taken to obtain good alignment, unless the
patient is advanced in years. The older methods — Liston's

THE FEMUR 439

splint, and extension by weights, etc. — have been replaced by
that introduced by Whitman. The limb is abducted, so that
the proximal fragment is forced against the anterior part of the
capsule by the neck and the broken surfaces are brought into
apposition. The limit of normal abduction is determined by
a comparison with the sound limb, and the fractured limb is
maintained in this position, and with the capsule tense, by a
plaster case. When the limb is adducted after union has
occurred, the head rotates upwards, and it is found that there
is little or no .shortening.

2. Fractures through the distal part of the neck of the femur,
although occasionally caused by indirect violence, are commonly
due to falls on the greater trochanter. Owing to the line of the
femoral attachment of the capsule (p. 420) the fracture is
intra-capsular anteriorly but extra- capsular posteriorly. When
the injury is due to direct violence, the neck is frequently driven
into the greater trochanter, where it may remain impacted, or
the trochanter may be comminuted. In the latter condition
there is considerable widening of the bony prominence in an
antero-posterior direction, and this is more readily determined
owing to the relaxation of the ilio-tibial tract.

When the fracture is not impacted there is definite shortening,
and the limb is everted, partly owing to its weight and partly
owing to the lateral rotator muscles, which are much stronger
than the medial rotators. In impacted fractures these signs '
may be entirely lacking and, in addition, there may be some
slight power of movement at the joint.

As this variety of fracture usually occurs in healthy adults,
good bony union is generally obtained, but care must be taken
to ensure a proper alignment of the limb and prevent shortening.

Fractures of the Shaft of the Femur.— When due
to indirect violence the fracture is usually oblique or spiral, and
the fragments tend to override one another. The displacement,
therefore, is greater in amount than it is in fractures due to
direct violence, where the break tends to be transverse. The
degree of displacement depends on the direction of the causative
force, the action of muscles, and the influence of gravity.

In Fracture of the Proximal Third of the Shaft the
proximal fragment becomes abducted and laterally rotated by
the muscles attached to the greater trochanter, and it is flexed
by the ilio-psoas. The amount of flexion is increased, as the
distal fragment, which is drawn proximally by the hamstrings

440 THE INFERIOR EXTREMITY

and adductors, passes behind the proximal fragment and tilts
it forwards. In addition the distal fragment becomes laterally
rotated owing to the weight of the foot and the action of the
adductors.

As the proximal fragment is so short and so deeply placed,
it cannot be controlled easily, and the fracture is, therefore,
very difficult to treat satisfactorily. The distal fragment may
be brought into line with the proximal fragment by putting the
limb up, flexed and abducted, on a double-inclined plane. In
this position the knee is passively flexed and the hamstrings
are relaxed. The application of extension by weight and pulley
helps to counteract the overlapping of the fragments.

Fractures in the Middle Third of the Shaft are more
easily dealt with on account of the greater length of the proximal
fragment. The displacements are due to the same forces as
have been described for fracture in the proximal third. Ex-
tension by weight and pulley is employed to counteract the
shortening, and eversion of the limb is prevented by maintaining
the foot at right angles to the bed.

When the fracture is due to indirect violence, the extremities
of the fragments are sometimes sharp and pointed. They may
become embedded in the muscles, and so give rise to difficulty
in reduction.

In infants this fracture is best treated in the following way.
A gallows is placed across the bed immediately above the child's
pelvis. The thighs are flexed at right angles to the pelvis and
the legs are extended by weights and extension, acting over
pulleys which are fixed to the gallows. The weights used are
just sufficient to counterbalance the weight of the pelvis and
lower limbs, which act as the counterpoise.

In Fractures of the Distal Tljird of the Shaft (Supra-
condylar) the distal fragment is rotated backwards by the
gastrocnemius. At the same time it is drawn proximally by
the quadriceps and hamstrings, and, owing to the first dis-
placement, it is drawn up behind the proximal fragment. A
double-inclined plane is used to relax the gastrocnemius, and
extension is applied to counteract the shortening, which con-
stitutes the chief deformity. Owing to the small size of the
distal fragment, the application of extension may be a matter
of difficulty. A horse-shoe shaped stirrup, which is attached
to the distal fragment by sharp screws, maintains satisfactory
extension and has been used with success.

THE REGION OF THE KNEE 441

The Posterior Compartment of the Thigh contains the powerful
hamstring muscles, the sciatic nerve and its two terminal branches, the tibial
(int. popliteal) and the common peroneal (ext. popliteal) nerves.

The hamstring muscles all arise from the ischial tuberosity. The
Biceps, which passes distally and laterally, possesses.' a second, or short
head of origin, which arises from the lateral lip of the linea aspera. These
two heads unite opposite the lateral epicondyle, and their common tendon,
which is easily felt through the skin, extends to the head of the fibula for its
insertion. The biceps flexes the knee-joint, and is capable of producing a
certain amount of lateral rotation ; in addition, it acts as an extensor of the
hip-joint.

The Semimembranosus passes distally along the medial side of the posterior
compartment of the thigh, and is inserted into a groove on the postero-medial
aspect of the medial condyle of the tibia. The Semitendinosus is smaller in
bulk and lies on the surface of the semimembranosus. Its tendon (p. 443)
extends to the proximal part of the medial surface of the tibia, where it is
inserted behind the tendons of the gracilis and sartorius, from which it is
separated by a synovial bursa (p. 450). Like the biceps, both these muscles
extend the hip and flex the knee, but, since they are related to the medial
aspect of the latter joint, they cause a slight amount of medial rotation.

All three muscles are supplied by the sciatic nerve (L. 4, 5, S. i, 2, and 3),
but the branch to the short head of the biceps frequently arises from the
common peroneal nerve (ext. popliteal).

The Sciatic Nerve passes distally through the posterior
compartment of the thigh on the posterior surface of the
adductor magnus. Proximally it is crossed by the long head
of the biceps, and in the rest of its course it is overlapped by
the semimembranosus. It gives off branches of supply, which
enter the flexor muscles near their origin, and, together with
the obturator nerve, it supplies the adductor magnus. In the
middle third of the thigh, it ends by dividing into the common
peroneal (L. 4, 5, S. i and 2) and the tibial (L. 4, 5, S. i, 2, and
3) nerves.

The perforating arteries from the profunda femoris (p. 410)
enter the posterior compartment of the thigh by piercing the
adductor magnus close to its insertion into the linea aspera.
They form a longitudinal series of anastomoses with one another.
Proximally the first perforating artery takes part in the crucial
anastomosis (p. 418) ; distally, the third and fourth perforating
arteries anastomose with the proximal muscular branches of
the popliteal (p. 445).

THE REGION OF THE KNEE.

Surface Landmarks. — As there is little elasticity in the
ligamentum patellae, the patella remains at a constant distance

442

THE INFERIOR EXTREMITY

from the tibial tuberosity, whether the knee-joint is flexed or
extended. In extension of the knee-joint, the distal part of
the articular surface of the patella is in contact with the
proximal part of the trochlea (Fig. 131), but,, when the joint is
flexed, the patella is drawn downwards by its ligament so that
its articular surface is more fully in contact with the femur.

Vastus lateral

\ \ I

"V astus medialis
Quadriceps tendon
Adductor tubercle

Depression over latera
meniscus'

Head of fibula

Depression over medial
meniscus

Ligamentum patellae

Tibial tuberosity

FIG. 127. — Surface Landmarks in the Region of the Knee.

When the knee is passively extended the patella may be
moved from side to side, and, owing to the elasticity of the
quadriceps muscle, it may be pushed distally. When the joint
is distended with fluid the articular surfaces of the patella
and the femur are separated from one another. This condition
is termed " floating patella," and, when the patella is gently
tapped, it may be made to knock against the femur.

The ligamentum patella can be traced from the apex of the
patella to the tibial tuberosity. It is about two inches long and

THE REGION OF THE KNEE 443

its mid-point corresponds to the level of the knee-joint. On
each side of the ligamentum patellae a slight triangular depression
can be seen when the knee is semi-flexed. The lateral depression
is bounded distally by the anterior margin of the proximal
extremity of the tibia, laterally by the margin of the articular
surface of the femur , and medially by the ligamentum patellae.

The medial depression is bounded by the corresponding
parts of the femur, tibia, and patellar ligament. Palpation
of the collateral boundaries of these depressions readily reveals
the presence of lipping of the femoral condyles in rheumatoid
arthritis. Aspiration of the knee-joint may be carried out
through either of these areas, but when the joint is distended
with fluid, the surface depressions are no longer visible.

The tibial tuberosity (tubercle) can easily be palpated ; it
lies one inch distal to the line of the knee-joint. The head of the
fibula is placed on the same level as the tibial tuberosity, but on
a plane posterior to it. It serves as a guide to the common
peroneal (ext. popliteal) nerve, which can be rolled against the
bone as it crosses the lateral aspect of the fibular neck.

The lateral aspect of the lateral condyle and the medial
aspect of the medial condyle of the femur are both subcutaneous.
The adductor tubercle is the most proximal palpable point on the
medial condyle, and when the knee is semi-flexed the tendon of
the adductor magnus can be traced proximally from it.

In active extension of the knee-joint the tendon of the
rectus femoris forms a tense band, ij inches wide, which is
inserted into the proximal border of the patella. In the same
position of the limb the vastus medialis forms a prominent
elevation to the medial side of the tendon, and the vastus lateralis
forms a similar elevation on the lateral side but it is placed at a
more proximal level. A very definite depression lies immediately
distal to the elevation produced by the vastus lateralis ; it is
bounded medially by the rectus femoris and laterally by the
ilio-tibial tract. The latter forms a distinct ridge, which crosses
the antero-lateral aspect of the joint and can be traced distally
to its attachments on the lateral condyle of the tibia and the
head of the fibula.

When the knee is flexed against resistance, the tendons of
the hamstrings are rendered prominent and can be palpated
almost to their respective insertions. The tendon of the semi-
membranosus is felt on the medial side of the tendon of the
semitendinosus , which, however, is more superficial. On the

444

THE INFERIOR EXTREMITY

lateral aspect of the distal part of the thigh, the fingers can be
made to sink into the popliteal fossa, through the interval which
is bounded behind by the biceps tendon and in front by the
ilio-tibial tract. A similar interval can be made out on the
medial side behind the tendon of the adductor magnus.

The Popliteal Fossa lies behind the knee-joint and extends
beyond it in both directions. Its roof, which is formed by a
thin but strong sheet of deep fascia, is pierced near its centre

Adductor magnus
tendon

Vastus medialis

Popliteal fossa
Semimembranosus

Medial condyle of femur
- Semitendinosus

FIG. 128.— The Medial Side of the Knee.

by the small saphenous vein. Proximally, the fossa is bounded
by the biceps on the lateral side, and by the semimembranosus
and semitendinosus on the medial side ; distally, it is bounded
by the two heads of origin of the gastrocnemius. The floor of
the fossa is formed by the popliteal surface of the femur, the
posterior ligament of the knee-joint, and the posterior surface
of the popliteus, which is covered by a strong layer of fascia.

The Popliteal Artery begins at the hiatus tendineus in
the adductor magnus (p. 412), where it is continuous with the
femoral artery. As it passes through the popliteal fossa it
inclines laterally till it reaches the middle line of the limb, and
then descends vertically to the distal border of the popliteus,

THE REGION OF THE KNEE 445

where it terminates by dividing into the anterior and posterior
tibial arteries. Throughout its course the artery is very deeply
placed, and it lies in direct contact with the posterior ligament
of the knee-joint. ,

Ligature of the Popliteal Artery may be carried out for
aneurism, or following wounds of the vessel. The incision lies
behind and parallel to the tendon of the adductor magnus,
and when the skin is divided, the great saphenous vein and the
saphenous nerve are exposed. These structures are retracted
backwards together with the sartorius, which is seen when the
deep fascia is incised (Fig. 128). The wound is then deepened
between the adductor magnus and the semimembranosus.
Flexion of the knee relaxes the latter muscle and enables it to
be retracted so as to permit the finger to be inserted into the
fat which intervenes between the popliteal artery and the femur.
The sheath of the vessel is carefully incised on its medial aspect,,
and the popliteal vein and the tibial nerve, which lie on its
postero-lateral side, are thus avoided.

The Branches of the Popliteal Artery can be divided into three groups :
(a) muscular, (b) cutaneous, (c) articular, (a) The proximal muscular branches
supply the hamstrings and anastomose with the perforating arteries (p. 410);
the distal muscular branches are distributed to the muscles of the calf, (b)
The cutaneous branch supplies the skin of the calf, and is accompanied by the
medial cutaneous branch of the tibial nerve, (c) The articular branches are
five in number :

1. The middle genicular (azygos) artery enters the knee-joint by piercing
the posterior ligament, and is distributed to the structures within the capsule.

2. The superior genicular arteries, lateral and medial, wind round the
femur, proximal to the condyles. They are in close contact with the bone,
and anastomose with one another anteriorly. In addition, they anastomose
with the inferior genicular arteries, and with the descending branch of the
lateral circumflex and the articular branch of the arteria genu suprema
(p- 4I3)- The latter anastomosis helps to re-establish the circulation in the
leg when the popliteal artery is ligatured in its proximal part.

3. The inferior genicular arteries, lateral and medial, wind round to the
anterior aspect of the knee. In their course they pass under cover of the
tibial and fibular collateral (internal and external lateral) ligaments respec-
tively, and they anastomose with one another under cover of the ligamentum
patellae. They communicate with the superior genicular arteries, and so
take part in the important anastomosis around the knee-joint.

The Tibial (Internal Popliteal) Nerve (L. 4, 5, S. i,

2, 3) arises from the sciatic in the posterior compartment of
the thigh and extends distally in the middle line of the limb.
In the popliteal fossa it lies superficial to the popliteal vessels
and it crosses them obliquely from the lateral to the medial side.
At the distal border of the popliteus the tibial nerve passes

446 THE INFERIOR EXTREMITY

deep to the soleus and enters the posterior compartment of the
leg.

As it traverses the popliteal fossa, the tibial nerve gives off
(a) muscular, (b) cutaneous, and (c) articular branches. The
muscular branches supply both heads of the gastrocnemius, the
soleus, the plantaris, and the popliteus. The cutaneous branch
is termed the medial cutaneous nerve of the calf (ramus
communicans tibialis). It descends between the two heads of
the gastrocnemius and unites with the peroneal anastomotic
nerve (r. communicans fibularis) to form the nervus suralis
(external saphenous) (S. i and 2) (p. 473). The articular twigs,
three in number, supply the knee-joint.

The Common Peroneal (Ext. Popliteal) Nerve (L. 4,
5, S. i, 2) passes distally and laterally in close relation to the
medial aspect of the biceps tendon, and leaves the popliteal
fossa in the interval between the tendon and the lateral head
of the gastrocnemius. It then descends behind the head of
the fibula and winds round the lateral aspect of the fibular
neck, piercing the origin of the peronaeus longus. In this
situation the nerve ends by dividing into the superficial and
deep peroneal nerves (musculo-cutaneous and anterior tibial)
(L. 4, 5, S. i).

The common peroneal nerve gives off no muscular branches,
but it supplies articular twigs to the knee-joint and gives origin
to the lateral sural nerve (L. 4, 5, S. i), which supplies the skin
over the proximal part of the tibialis anterior, and the peroneal
anastomotic nerve, which helps to form the nervus suralis.

The Popliteal Lymph Glands are divided 'into a superficial
and a deep group. The superficial lymph glands surround the
small saphenous vein as it pierces the deep fascia. They receive
aflerents from the lateral aspect of the foot and leg, and their
efferents open into the deep group.

The deep lymph glands are embedded in the fat which
surrounds the popliteal vessels. They receive the efferents
of the superficial group, and, in addition, most of the numerous
lymph vessels from the deep tissues of the calf and the sole of
the foot. The remainder of the latter pass direct to the deep
subinguinal lymph glands (p. 400). The efferents of the deep
popliteal lymph glands terminate in the deep subinguinal
group.

Abscesses arising in these lymph glands follow some septic
infection of the leg or toes. Owing to the depth at which the

THE REGION OF THE KNEE 447

pus lies from the surface, its presence is difficult to determine
at an early stage, but early diagnosis is necessary, as when
evacuation is delayed the abscess cavity takes a long time to
granulate up. This slow closure is partly due to the rigid walls
of the cavity, which are formed by the hamstring tendons, and
partly to the destruction of the fat in which the lymph glands
are embedded.

Abscesses in the popliteal fossa are best approached from
the lateral aspect of the knee. An incision is made behind the
lateral intermuscular septum (p. 402), but in front of the biceps
tendon. When the deep fascia is divided, a pair of dressing
forceps can be passed medially between the biceps and the
femur, and the pus is evacuated by Hilton's method in order to
avoid injuring the large vessels and nerves.

The Popliteus Muscle arises within the capsule of the knee-joint from
the lateral aspect of the lateral femoral condyle. It passes distally and
medially across the joint, and is inserted into the proximal part of the posterior
surface of the tibia. Near its origin the popliteus intervenes between the
lateral meniscus (semilunar cartilage) and the fibular collateral ligament (p.
455). It is supplied by the tibial (int. popliteal) nerve (L. 4, 5, and S. i)
and acts as a flexor of the knee-joint. In addition, when the tibia is fixed
the popliteus acts as a lateral rotator of the femur, and when the tibia is free
to move it acts as a medial rotator of the tibia.

Superficial Veins of the Lower Limb. — A venous arch
extends across the dorsum of the foot near the heads of the
metatarsal bones. It is continued backwards along the medial
border of the foot as the great saphenous vein, which ascends in
front of the medial malleolus and then along the medial border
of the tibia to the medial side of the knee-joint. The remainder
of its course may be indicated by a line joining the adductor
tubercle to the fossa ovalis (p. 401). At the latter point the
great saphenous vein passes through the deep fascia and joins
the femoral vein.

The small saphenous vein arises at the lateral extremity of
the dorsal venous arch and passes backwards along the lateral
border of the foot. From behind the lateral malleolus it
ascends obliquely in the superficial fascia of the back of the
leg, and near the centre of the popliteal fossa it pierces the
fascial roof to join the popliteal vein. It usually communicates
with the great saphenous by a branch which winds round the
postero-medial aspect of the knee, or by one which arises at a
lower level and crosses in front of the proximal part of the tibia.

Except for a short distance from their termination, both
saphenous veins lie in the superficial fascia and1 therefore

448 THE INFERIOR EXTREMITY

receive no muscular support. Owing to this lack of support
and to the action of gravity, these veins are very liable to
become varicose. Both veins contain numerous valves, which
help to support the column of blood. The rupture of one of
these valves increases the strain on the one distal to it, which
in turn gives way. The unsupported vessel walls are not strong
enough to support the column of blood when the patient is in
the erect attitude, and they consequently become dilated and
varicose. The middle third of the great saphenous vein is most
frequently affected, but its proximal and distal parts and the
small saphenous vein are often involved.

When the patient adopts the recumbent posture, the veins,
though varicose, are able to fulfil their function, and in conse-
quence, elastic bandages, stockings, etc., which are used as a
mechanical support, should be applied before the patient rises
from this posture.

Owing to the obstruction to the venous return the vitality
of the skin is diminished, especially in the distal part of the
limb, and chronic ulceration tends to arise after trivial injuries
in this region. Healing is always tedious and may not occur
unless the patient is kept in bed with the limb slightly elevated.
This position assists the venous return, and so improves the
vitality of the affected part.

The Bursae around the Knee.— Numerous bursse, some
of which communicate with the interior of the joint, lie in
relation to the tendons around the knee.

Anterior. — (i) The supra-patellar bursa almost invariably
communicates with the joint. It lies behind the tendon of
the quadriceps and is separated from the femoral diaphysis by
an extra-synovial pad of fat (Fig. 131). It extends upwards
for a hand-breadth above the proximal border of the patella,
and is outlined in hydrops of the joint. Fluid may be aspirated
from the knee-joint through this bursa.

(2) The prepatellar bursa is subcutaneous and lies in front
of the distal part of the patella and the proximal part of the
ligamentum patellae. When the bursa is exposed to much
pressure, effusion is apt to occur into it and the condition may
become chronic, with the formation of fibrous bands and " melon-
seed " bodies (" housemaid's knee "). The prepatellar bursa,
when thus affected, may be removed through a semilunar
incision, the base of which is distal, so that pressure on the scar
is subsequently avoided.

THE REGION OF THE KNEE 449

When enlarged, this bursa projects beyond the margins of
the ligamentum patellae,, and so is brought into close relationship
with the capsule of the joint. In acute suppurative conditions,,
therefore, it is important that the bursa should be incised and
drained at an early stage to prevent the joint from becoming
infected. An incision is made on each side of the middle line
so that the bursa may be thoroughly drained.

(3) A small subcutaneous bursa is sometimes present in front
of the tibial tuberosity and the distal part of the ligamentum
patellae.

(4) The infra-patellar bursa is placed between the proximal
extremity of the tibia and the deep surface of the ligamentum
patellae. It is only separated from the synovial lining of the
joint by the infra-patellar pad of fat. When effusion takes
place into this bursa, there is slight fulness on each side of the
ligament near the tibial tuberosity, and full flexion causes pain
in this region.

Postero- Lateral. — (i) A bursa is situated between the
lateral head of the gastrocnemius and the capsule covering the
lateral femoral condyle ; it sometimes communicates with the
cavity of the knee-joint.

(2) A small bursa is usually interposed between the biceps
tendon and the fibular collateral (external lateral) ligament of
the knee.

(3) A protrusion of the synovial lining of the knee-joint
separates the tendon of the popliteus from the lateral condyle. It
varies in extent, sometimes forming a complete sheath for the
tendon and communicating distally with the cavity of the
proximal tibio-fibular joint (p. 460).

(4) A small bursa separates the popliteus tendon from the
fibular collateral ligament. It may be incorporated with the
preceding bursa, when the latter is of large size.

Postero-Medial. — (i) A bursa is placed between the medial
head of the gastrocnemius and the capsule covering the medial
femoral condyle. It is frequently in communication with the
knee-joint.

(2) A bursa, which frequently communicates with the
preceding, is situated between the medial head of the gastrocnemius
and the semimembranosus tendon.

Gradual enlargement of these bursse, accompanied by pain
and limitation of movement at the knee-joint, is sometimes met
with in gamekeepers and shepherds. This is said to be due

29

450

THE INFERIOR EXTREMITY

to the increased amount of flexion at the knee-joint which
is necessary when walking through heather and gorse. The
swelling usually enlarges distally in an intermuscular interval
and assumes a sausage -shape. Such swellings have been

FIG. 129. — Normal Knee-joint of a Child, aged four. Antero-posterior view.
The centre of ossification for the head of the fibula is not yet present.

mistaken for varicose veins, and they are usually much larger
than they appear to be, since they lie under the deep fascia.

(3) The tendons of the sartorius, gracilis, and semitendinosus
are separated from one another at their insertions, and from
the tibial collateral (internal lateral) ligament by one or more
bursse.

THE REGION OF THE KNEE 451

Ossification of the Distal Extremity of the Femur.— A

secondary centre appears in the cartilaginous distal extremity
of the femur during the ninth month of fcetal life. It is the
earliest secondary centre to appear, and following the general

FIG. 130. — Knee-joint of Child, aged thirteen. Lateral view. Observe the
epiphyseal lines on the tibia and fibula. A separate centre of ossification
is present for the tibial tuberosity. Note also the position of the head
of the fibula.

rule that epiphyses which ossify early unite late, it does not
join the diaphysis till the twenty-first year. Growth in length,
therefore, proceeds for a longer period at the distal than at the
proximal extremity of the femur (p. 420). The distal epiphyseal
line corresponds, anteriorly, to the proximal border of the
articular surface, and posteriorly, to the intercondylar line.

29 a

452 THE INFERIOR EXTREMITY

On the condyles the line is curved with a downward convexity,
and on the medial side it passes through the adductor tubercle.

Ossification of the Proximal Extremity of the Tibia.—
A secondary centre appears in the cartilaginous proximal
extremity of the tibia shortly before birth, and the epiphysis
which it forms includes both condyles and the tibial tuberosity.
Occasionally the tibial tuberosity possesses a separate centre
of ossification, which appears at the eleventh or twelfth year
and soon fuses with the rest of the epiphysis. The proximal
epiphysis of the tibia unites with the shaft at about the twenty-
fourth year. The epiphyseal line usually passes through the
articular surface for the head of the fibula.

The Patella does not begin to ossify till the third year, but
ossification is complete at puberty.

The Knee -Joint. — The Capsule of the knee-joint is
strongest on the posterior aspect of the joint, and it is quite
distinct on the lateral and medial aspects. Anteriorly it forms
a thin fibrous layer closely applied to the outer surface of the
synovial membrane, but, proximal to the patella and over the
area occupied by the patella, it is entirely deficient. On each
side of the patella the capsule depends for its strength on
the tendinous expansions of the vasti, lateralis and medialis
(p. 409).

Proximally, the line of attachment of the capsule crosses the
epiphyseal line on the lateral and medial condyles, but it remains
at least half an inch distant from the margins of the articular
surface. Posteriorly the capsule is attached to the proximal
margins of the articular surfaces and to the intercondylar line.
On this aspect, therefore, the line of attachment of the capsule
practically coincides with the epiphyseal line.

Distally, the capsule is attached to the tibial condyles, a
little beyond the margins of the articular surface.

The Synovial Membrane of the knee-joint is very extensive,
and its arrangement is complicated by the presence of the
intra-articular ligaments and menisci. It lines the deep aspect
of the capsule, from which it is reflected on to those parts of the
femur and tibia which are intra-capsular but non-articular.
From the antero-distal part of the joint a triangular fold of
the synovial membrane passes proximally and backwards, to
be attached by its apex to the anterior extremity of the inter-
condylar fossa. This fold is termed the patellar synovial fold
(ligamentum mucosum), and its free margins are known as the

THE REGION OF THE KNEE

453

alar folds (ligamenta alarm). An extra-synovial but intra-
capsular pad of fat lies behind the ligamentum patellae,, and the
portion of it which is carried in between the two layers of the
patellar synovial fold (Fig. 131) is frequently the site of hyper-
trophy (lipoma arborescens). In this condition grape -like
pieces may become detached and constitute loose bodies within

Supra-patellar bursa
Quadriceps tendon

Distal epiphyseal line

of femur

Anterior cruciate lig.

Oblique popliteal lig.

Proximal epiphysea
line of tibia

Prepatellar bursa

Infra-patellar pad of fat
atellar synovial fold
^Ligamentum patellae

Deep infra-patellar bursa

Subcutaneous infra-patellar
bursa

FIG. 131. — Sagittal Section through the Knee-joint.

Light blue = articular cartilage. Green — periosteum.

Striped blue = tendons and ligaments. Red = synovial membrane.

the joint. Similar hypertrophy may affect the pad of fat which
intervenes between the femur and the supra-patellar bursa

(Fig. 131).

Both the femoral and the tibial surfaces of the menisci
(semilunar cartilages) are covered by the synovial membrane
(Fig. 132) which helps to attach their peripheral margins to
the tibia (coronary ligaments).

In the posterior part of the joint the synovial membrane is
drawn off the central part of the posterior ligament by the

29 &

454

THE INFERIOR EXTREMITY

posterior cruciate ligament. It covers both cruciate ligaments
anteriorly and on each side, so as to render them extra-synovial.

Protrusions of the synovial membrane escape from the
capsule to form the supra - patellar and the popliteus bursse
(p. 449).

The Ligamentum Patellae (p. 441) serves to strengthen

Distal epi-
physis of femur
Tibial
collateral
ligament
Anterior
. cruciate
ligament

Medial meniscus

Proximal epiphysis
of tibia

Lateral meniscus
Tendon of popliteus

Popliteus bursa

Fibular collateral
ligament

Proximal tibio-
fibular joint

Head of fibula ,

*

FIG. 132. — Oblique Section through the Right Knee-joint.

Light blue = articular cartilage. Green — periosteum.

Striped blue = ligaments and menisci. Red = synovial membrane.

the capsule anteriorly and takes the place of an anterior ligament
of the knee-joint.

The Tibial Collateral (Internal Lateral) Ligament is a
broad flattened band which strengthens the capsule on its
medial aspect. Proximally it is attached to the femur near
the adductor tubercle. It crosses the medial aspect of the
joint and is firmly adherent to the peripheral border of the medial

THE REGION OF THE KNEE 455

meniscus (p. 456). Distally, the tibial collateral ligament extends
to the proximal part of the shaft of the tibia, where it receives
attachment behind the semitendinosus tendon.

The Fibular Collateral (External Lateral) Ligament
forms a distinct rounded band, which is attached to the lateral
condyle of the femur about half an inch from its articular
margin. As it crosses the lateral aspect of the knee-joint, the
ligament is separated from the lateral meniscus by the popliteus
tendon, its associated bursa (p. 456), and the lateral inferior
genicular artery. Distally, it is attached to the head of the
fibula in close relation to the insertion of the biceps.

The collateral ligaments may be strained or torn during the
same violent movements of the joint which may give rise to
injury of the menisci. In the former condition tenderness is
experienced on palpation over the injured ligament, whereas,
when the menisci are involved, the tenderness is most marked
in the triangular depressions at the sides of the ligamentum
patellae (p. 443).

The Posterior part of the capsule is specially thickened
and helps the anterior cruciate ligament to prevent hyper-
extension of the joint. It is further strengthened by the oblique
popliteal ligament, which extends obliquely across the back of
the joint from the semimembranosus, at its insertion, to the
medial border of the lateral femoral condyle.

The Medial Meniscus (Int. Semilunar Cartilage) of the
knee-joint is interposed between the peripheral parts of the
medial condyles of the tibia and the femur. It is semilunar in
outline, and its two extremities are widely separated from one
another. The anterior extremity is attached to the anterior
part of the non-articular area on the top of the tibia, and in
addition it is connected to the anterior part of the lateral
meniscus by the transverse ligament. The posterior extremity
is attached to the posterior part of the non-articular area referred
to above (Fig. 133).

The Lateral Meniscus (External Semilunar Cartilage) is
nearly circular in outline, and its extremities are attached close
to one another. Its anterior extremity is attached to the tibia
immediately in front of the intercondylar eminence (tibial spine),
while its posterior extremity is attached to the eminence itself,
and is also connected with the posterior cruciate ligament
(Fig. 133).

The menisci are thickest round their peripheral borders and

29 c

456

THE INFERIOR EXTREMITY

thin away to their free central margins. The peripheral border
of the medial meniscus is firmly adherent to the tibial collateral
ligament, but the fibular collateral ligament is separated from
the lateral meniscus by the popliteus tendon, its synovial bursa,
and the lateral inferior genicular artery. On this account,
although both menisci are permitted a certain amount of move-
ment to enable them to accommodate themselves to the articular
surfaces in different positions of the joint, the medial meniscus
is the less freely movable of the two. Further, since the

FIG. 133. — The Menisci and their Attachments.

1. Transverse ligament.

2. Anterior cornu of medial meniscus.

3. Anterior cruciate ligament.

4. Medial tubercle of intercondyloid emin-

ence of tibia.

5. Medial meniscus.

6. Posterior cornu of medial meniscus.

7. Posterior cruciate ligament.

8. Fasciculus from lateral meniscus to

posterior cruciate ligament.

9. Posterior cornu of lateral meniscus.

10. Lateral tubercle of intercondyloid

eminence of tibia.

11. Lateral meniscus.

12. Anterior cornu of lateral meniscus.

extremities of the medial meniscus are more widely separated
from one another than those of the lateral meniscus, the latter
enjoys greater freedom.

Injuries of the menisci occur in forcible rotation of the flexed
or semi-flexed knee. The tibia may be rotated on the femur
when the latter is fixed, or the femur may be rotated on the
tibia when the tibia is fixed. Statistics show that the medial
meniscus suffers injury much more frequently than does the
lateral meniscus, and it is probable that the comparative
immunity of the lateral meniscus is due to its greater range of
movement.

When the tibia is fixed and the femur is suddenly and

THE REGION OF THE KNEE

457

violently rotated laterally, the lateral meniscus is able to follow
the movements of the lateral condyle, and in doing so it exerts
a strain on the thin concave margin of the medial meniscus
through the transverse ligament. As a result a concentric
splitting may occur in the anterior part of the medial meniscus,
or its anterior extremity may be torn through and dragged
towards the centre of the joint (Fig. 134, B).

In some subjects, either owing to their occupation or as the

FIG. 134. — Diagram to illustrate Injuries of the Medial Meniscus.

A. Normal position of the menisci.

B. Splitting of the medial meniscus caused by traction on the transverse ligament,
following violent lateral rotation of the femur on the fixed tibia.

C and D. Tearing of the anterior attachment of the medial meniscus caused by violent
flexion of the knee combined with medial rotation of the femur on the fixed tibia.

result of a constitutional disease, the capsule of the knee-joint
becomes sufficiently relaxed to permit a slight amount of
abduction and adduction. This constitutes a predisposing
cause to injury, as, owing to the increased freedom of separation
of the femur and tibia from each other, the menisci are more
likely to be caught between the two articular surfaces. In
extension of the knee-joint the somewhat flattened distal surface
of the medial condyle of the femur is in contact with the whole
of the medial meniscus. When the leg is extended, therefore,
forcible medial rotation of the femur on the tibia produces little
alteration in the shape of the meniscus. On the other hand,

458 THE INFERIOR EXTREMITY

when the leg is flexed the more convex posterior surface of the
femoral condyle is only in contact with the broader posterior
part of the medial meniscus, and in medial rotation of the
femur on the tibia the curve of this part is accentuated, while
the anterior part becomes correspondingly straighter. If the
violence of the rotatory movement is sufficient to tear its anterior
attachment, the meniscus resumes its semilunar outline, with
the result that its torn extremity projects into the centre of the
joint (Fig. 134). Subsequent extension of the joint catches the
meniscus between the two articular surfaces.

The Surgical Approach to the menisci is carried out with
the knee-joint flexed (Jones) in order to obtain good exposure.
The incision, which is convex forwards and extends for two inches
on each side of the line of the joint, does not quite reach the
margin of the patella, and a curved flap of skin and fascia is
reflected backwards. A vertical incision is made in the capsule
midway between the patella and the margin of the femoral
condyle, and the anterior extremity of the meniscus can then be
dragged forwards out of the wound. After it has been dealt with
the capsule is closed and the skin margins are reunited. As
the incision through the skin does not immediately overlie the
incision through the capsule, leakage of the synovial fluid is
hindered, while there is no subsequent weakening of the capsule
in flexion and extension, such as occurs when the incision
through it is made in a transverse direction.

The Cruciate Ligaments extend from the intercondylar
fossa of the femur to the intercondylar area on the top of the
tibia. They cross one another in the centre of the joint and are
therefore iritra-capsular, but they are excluded from the synovial
cavity by the synovial membrane. The anterior cruciate ligament
is attached to the top of the tibia in front of the intercondylar
eminence, and passes upwards and backwards to reach the
posterior part of the medial aspect of the lateral femoral condyle.
These two bony points are farthest from one another when the
knee-joint is fully extended, and in this position of the limb,
therefore, the ligament is tense. Aided by the collateral
ligaments and the thickened posterior part of the capsule, the
anterior cruciate ligament is sufficiently strong to prevent
hyper-extension of the joint unless excessive force is applied.
The posterior cruciate ligament is attached to the posterior part
of the non-articular area on the top of the tibia, and extends
upwards and forwards to the anterior part of the lateral aspect

THE REGION OF THE KNEE 459

of the medial femoral condyle. It is relaxed in extension, but
becomes tightened during flexion of the joint.

Severe strains of the knee may cause rupture of one or both
cruciate ligaments without leading to actual dislocation of the
joint. In addition to preventing hyperextension of the knee,
the anterior cruciate ligament prevents the tibia from being
moved bodily forwards on the femur when the joint is passively
extended. If, following injury, this passive movement is
obtained, the diagnosis of rupture of the anterior cruciate
ligament can be made with some degree of certainty. Similarly
the posterior cruciate ligament prevents the same passive
movement of the tibia on the femur when the knee is flexed,
and this movement can only be obtained when the ligament
is ruptured.

The articular surfaces of the tibial condyles are separated from one
another by a roughened non-articular area, which corresponds to the inter-
condylar fossa of the femur. This area, which is narrowest centrally, where
it is raised up to form the inter condylar eminence (tibial spine), gives attach-
ment to the inter-articular menisci and ligaments. Near its anterior margin
it gives attachment to the anterior extremity of the medial meniscus and
to the anterior cruciate ligament. The anterior extremity of the lateral
meniscus is attached immediately in front of the intercondylar eminence,
while its posterior extremity is attached to the eminence itself. The posterior
extremity of the medial meniscus receives attachment immediately behind
the eminence, and behind that lie the posterior cruciate ligament and the
posterior part of the capsule (Fig. 133).

Fracture of the Intercondylar Eminence (Spine) of the Tibia is a
somewhat rare injury, which has been brought to light by the use of radio-
graphy. Forcible extension of the femur upon the fixed and medially
rotated tibia causes the lateral margin of the medial femoral condyle to
impinge on the medial tubercle of the eminence, and so fracture it. Similarly,
when the tibia is fixed in lateral rotation, forcible extension may cause the
lateral condyle to fracture the lateral tubercle of the eminence (Jones).

It would appear that the injury only occurs in cases where one or other
tubercle is unusually well developed. The condition causes limitation of
movement, especially of extension, and if absolute rest in the extended
position fails to produce a good result, or if the case is one of long standing,
operative interference is advisable. The best exposure is obtained by splitting
the patella vertically, the knee being kept flexed. When the two fragments
are separated, the patellar sy no vial fold (ligamentum mucosum, p. 452) is
exposed and divided, and the region of the intercondylar eminence can then
be investigated. There is no necessity to wire the patella subsequently.

Spread of Tuberculous Disease in the Region of
the Knee-Joint. — Tuberculous disease at the distal end of the
femur usually commences in the distal part of the diaphysis,
and nearer to its posterior than to its anterior surface. It may
spread upwards along the diaphysis, or it may pass horizontally
towards the surface. In the latter case it usually spreads

460 THE INFERIOR EXTREMITY

backwards and readily breaks through the thin compact bone
(cortex) of the popliteal surface of the femur, giving rise to a
popliteal abscess. Tuberculous disease originating in the distal
part of the femoral diaphysis rarely involves the knee-joint,
since in the first place, it is extra-capsular ; and in the second
place, it finds less difficulty in spreading to the popliteal fossa
than in passing through the epiphysis to gain the joint. If,
however, the disease spreads forwards and breaks through the
periosteum, it infects the supra-patellar bursa and then involves
the joint.

When tuberculous disease originates in the proximal end of
the tibial diaphysis it is entirely extra-capsular, and it commonly
spreads distally along the shaft. It may, however, penetrate
the periosteum and infect the soft parts on the posterior or
lateral aspects, or cause a subcutaneous abscess on the medial
aspect. Very rarely the disease may break through the articular
cartilage and infect the proximal tibio-fibular joint. Should
this joint cavity communicate with the knee-joint through the
popliteus bursa (p. 449), the knee-joint itself will be secondarily
infected.

When the patella is the primary site of tuberculous disease,
spread to the knee-joint is likely to occur, since only the articular
cartilage intervenes.

The Surgical Approach to the Knee- Joint. — The
route chosen in any particular case depends partly on the area
of the joint which is involved and partly on the ultimate aim
of the operation. The age of the patient, too, may have some
influence in determining the procedure to be adopted.

Drainage is difficult to obtain in suppurative arthritis owing
to the complicated arrangement of the synovial membrane.
Incisions may be made midway between the margin of the
femoral condyle and the margin of the patella, on each side, in
order to allow a tube to be passed across the joint. From the
medial opening a director may be passed backwards across the
medial surface of the medial condyle of the femur just below
the attachment of the tibial collateral ligament. The point of
the instrument is cut down upon when it reaches the posterior
synovial pouch (p. 462). A similar proceeding can be carried
out on the lateral side, and, finally, an incision should be made
into the proximal part of the supra-patellar bursa. Through
these various incisions tubes may be arranged so as to provide
adequate drainage.

THE REGION OF THE KNEE

461

In young subjects, Inspection of the Joint may be carried out
with least damage through the lateral J -shaped incision of
Kocher or through a similar incision on the medial side. The

Cut edge of synovial membrane

Posterior surface
of patella

Posterior cruciate
ligament
Patellar synovial
fold (ligamentum
mucosum)
Anterior cruciate
ligament

Anterior cornu of
lateral meniscus

Infra-patellar pad of fat

Ligamentum patellae, „
posterior surface

Tuberosity of tibia,
posterior cut surface

Periosteum of tibia, left attached
to tuberosity

FIG. 135. — Complete Exposure of the Knee-joint. The dissection is described
on p. 462. The synovial membrane is shown in purple.

limb is slightly flexed over a sandbag, as the interior of the joint
is most accessible in this position. The incision, which begins
about 2\ inches proximal to the patella and a ringer's breadth
from its lateral margin, descends vertically over the femoral
and tibial condyles and then curves gently forwards to a point

462 THE INFERIOR EXTREMITY

about i£ inches beyond the tibial tuberosity. When the skin
and fasciae have been elevated and retracted; the vastus lateralis
and its tendinous expansion which passes to the lateral border
of the patella are exposed, together with the patella and the
ligamentum patellae. The joint is then opened by deepening
the vertical part of the incision. Freer access is gained by
dividing the infra-patellar pad of fat and its synovial covering
and by elevating the ligamentum patellae from the tibia. In
the child the ligament is freed by removing a slice of cartilage
from the tibial tuberosity, but in the adult the tuberosity will
require to be chipped off with a chisel. In both cases the
periosteum at the distal border of the tuberosity must not be
divided, since it serves to retain the tuberosity in position
subsequently. Thereafter the patella, together with the
quadriceps and the ligamentum patellae, may be rotated through
a right angle, and its surfaces can then be reversed by flexing
the knee. The whole of the joint cavity is then exposed, and
if necessary, excision of the joint can be performed (Fig. 135).

Excision of the Knee- Joint. — When it is decided before
the operation that excision of the joint is necessary, a large
U-shaped incision gives the best access. The transverse limb
lies midway between the patella and the tibial tuberosity, and
the vertical limbs ascend immediately in front of the collateral
ligaments. This incision is to be recommended because it
provides an anterior flap, should the condition of the joint, as
revealed by the operation, call for amputation rather than
excision.

The initial incision divides the skin, fascia, and the
supra-patellar tendon, and opens into the cavity of the joint,
which may be widely exposed by flexing the knee.

The cruciate ligaments are then removed, and this step
enables the surgeon to dissect the synovial membrane from the
lateral and medial parts of the posterior ligament. In this
situation synovial pouches extend upwards behind the condyles,
and, unless they are removed, they may give rise to subsequent
recurrence of the disease.

After resection of the cruciate ligaments, it is impossible to
obtain a joint which is both stable and movable, and as stability
is of primary importance, osseous ankylosis should be aimed at.
This result is obtained by removing the articular cartilage and
a layer of bone from the condyles of the femur and tibia. When
the disease has originated in the synovial membrane and the

THE REGION OF THE KNEE 463

bones are not affected, the amount of bone removed should be
just sufficient to ensure firm osseous union. In these cases the
femur is divided just distal to the attachments of the collateral
ligaments, while a slice, a quarter of an inch thick, is removed
from the tibia. Owing to the obliquity of its long axis (p. 464),
the femur must be divided parallel to the line of the joint and not
at right angles to its axis, in order to maintain the limb in its
normal alignment. Since the epiphyseal lines are not interfered
with in either bone, the amount of permanent shortening is
usually slight, and it serves to prevent the foot from dragging
on the ground when the patient is able to walk again.

The articular surface of the patella and the anterior articular
surface of the condyles should also be removed in order to
render the resulting ankylosis more secure.

The posterior ligament of the joint is left intact when
possible, as it protects the vessels in the popliteal fossa (Fig.
131). The middle genicular (azygos) artery will require to be
ligatured as it enters the joint after piercing the ligament.

After the anterior flap of skin and fascia has been replaced,
but before it is sutured, a long nail may be driven through each
tibial condyle into the corresponding condyle of the femur.
These nails should be introduced parallel to the long axis of the
tibia, and care must be taken lest they penetrate the popliteal
surface of the femur. This arrangement secures the bones in
position until bony union occurs. Thereafter the wound is
stitched up in layers.

Genu Valgum. — Under normal conditions a line drawn
from the centre of the femoral head to a point midway between
the two malleoli passes midway between the femoral condyles
at the knee-joint. In this way the weight of the trunk is
transmitted evenly to the two tibial condyles and thence to
the tarsal bones.

In rickets, owing to irregular growth and ossification near
the epiphyseal line, the medial part of the distal extremity of
the femoral diaphysis may become abnormally enlarged in a
downward direction. As a result, the medial part of the
epiphysis is thrust distally so that the plane of the knee-joint
is directed downwards, backwards and laterally instead of
vertically downwards. This constitutes the condition of genu
valgum. A plumb-line dropped from the femoral head passes
to the lateral side of the centre of the knee-joint and to the
medial side of the centre of the ankle-joint. The deformity

464 THE INFERIOR EXTREMITY

may be so great that the angle between the long axes of the
femur and tibia, which is normally about 170°, may approach
90°. When the knee is flexed, however, the deformity disappears,

FIG. 136. — Genu Valgum. (From a Radiogram by Dr. Claude Gouldes-
brough. ) Observe the increased growth of the medial part of the distal
end of the diaphysis of the femur.

as the posterior surfaces of the femoral condyles are not affected
and the tibia itself has undergone no alteration. The weight
of the trunk is no longer transmitted evenly to the tarsus, the
pressure being now distributed over the medial border of the
foot. An undue strain is therefore thrown on the plantar

THE REGION OF THE KNEE 465

calcaneo-navicular (" spring ") ligament (p. 484), and the
condition of flat-foot is brought about. In some cases flat-foot
is not the result but the cause of genu valgum. In the attitude
of rest adopted by young adolescents who are the subjects of
flat-foot, the feet are turned laterally and separated widely
from one another, while the knees are slightly flexed and the
thighs are adducted. When the limbs are in this position, the
medial condyle of the femur is tilted up off the tibia, stretch-
ing the tibial collateral ligament. The body-weight is now
transmitted through the lateral condyle of the femur, and
owing to the diminished pressure on the medial part of the
epiphyseal cartilage, the medial part of the distal extremity of
the diaphysis undergoes abnormal growth. Thus the apparent
genu valgum of the attitude of rest becomes transformed into
a real genu valgum.

Certain anatomical changes are found in adults in whom
the rhachitic knock-knee of childhood has been permitted to
remain uncorrected. The patella may become displaced
laterally so that, on flexion of the knees, it slips backwards over
the lateral aspect of the joint. The biceps tendon sometimes
becomes shortened and causes an appreciable amount of lateral
rotation of the tibia. The disability caused by these changes
may be relieved by medial cuneiform osteotomy of the femur
(p. 438), combined with transplantation of the tibial tuberosity
with the attached ligamentum patellae to the medial aspect of
the tibia, in exaggerated cases.

Genu Varum.— Overgrowth of the lateral part of the
distal extremity of the femoral diaphysis or of the opposing
part of the tibial diaphysis may occur in rickets, giving rise to
the condition of " bow-knee " or genu varum. In this case
the plumb-line dropped from the centre of the femoral head
passes medial to the centre of the knee-joint, but lateral to the
centre of the ankle-joint. As a result, the body- weight is
distributed mainly over the lateral part of the foot, which is
so well adapted to bear the increased strain (p. 492) that but
little disability is experienced. Further, since the knees are
widely separated, they do not have to avoid each other in
walking, as is the case in genu valgum.

If the child is kept off its feet, the bones tend to recover
their normal shape. This tendency is only apparent so long
as the bones remain soft. After the age of six or seven the
rhachitic softening disappears and the bones become more

30

466 THE INFERIOR EXTREMITY

brittle. After this age, therefore, subcutaneous fracture or
cuneiform osteotomy (p. 438) is necessary to overcome the
deformity.

Injuries in the Region of the Knee.— Supra-condylar
Fracture of the Femur (p. 440) is sometimes converted into a
T-shaped fracture involving the knee-joint, by a vertical splitting
of the distal fragment through the intercondylar fossa. The
nature of the injury may be determined by the widening of the
distal extremity of the femur and the independent movements
of each condyle, and of the femoral shaft. There is usually
considerable effusion into the joint, and this, together with the
swelling of the surrounding parts, may mask the condition to
some extent. Manipulations to restore the correct alignment
are carried out with the knee flexed in order to relax the
gastrocnemius, and for the same reason the limb is then placed
on a double-inclined plane.

Separation of the Distal Epiphysis of the Femur usually
occurs between the ages of ten and fourteen, and is due to violent
hyperextension of the knee. This movement throws a severe
strain on the posterior part of the capsule, which is of great
strength and consequently does not give way. The strain is
therefore transmitted to the femoral epiphysis and a diastasis
occurs. The causative force is usually applied to the leg from
behind, and on this account the epiphysis is usually displaced
forwards, overriding the distal extremity of the diaphysis.

Though this injury is by no means common, it is of great
importance, because it is usually complicated by injury of the
popliteal vessels. The laceration is frequently so extensive
that amputation may ultimately be necessary owing to the
occurrence of gangrene.

Reduction is obtained by traction on the leg and downward
pressure on the displaced epiphysis, the knee being flexed, and
the limb is then slowly extended. If, despite these manipulations,
the deformity recurs, the limb must be put up with the leg
flexed.

Fracture of Either Condyle alone may be caused by
violent movements of abduction or adduction. When the limb
is straightened there is little displacement, but a double-inclined
plane should be used in order to keep the gastrocnemius relaxed.
Less severe strains of a similar nature may result in avulsion
of the femoral attachment of a collateral ligament.

Fracture of the Patella may be due either to direct or to

THE REGION OF THE KNEE

467

indirect violence. In the former case, the displacement is slight
because, although the bone may be comminuted, the expansions
of the vasti (lateralis and medialis) are not torn and they serve
to prevent excessive separation of the fragments.

Fractures from indirect violence are brought about when the
patient, in the act of falling backwards, attempts to recover
his balance by powerful contraction of the quadriceps. At the
time of the accident the knee is semi-flexed and the patella is
snapped across the patellar surface of the femur. Rupture of
the quadriceps tendon or of the
ligamentum patellae are alterna-
tive possibilities to this fracture.
The two fragments are widely
separated, for, after the bone has
given way, the strain tears through
the expansions of the vasti ten-
dons (lateral patellar ligaments).

When conservative treatment
is adopted, the limb is placed on
an inclined plane, with the knee
extended in order to relax the
quadriceps. The flexion of the
hip still further relaxes the rectus
femoris. Fibrous union, together
with varying degrees of separa-
tion of the fragments, may be the
outcome of this method of treat-
ment, but this condition does not
necessarily cause much disability.

If the fragments are to be wired,
good exposure is obtained by a large U-shaped flap (p. 462). A
strong silver wire is passed transversely through each fragment
and the ends are twisted together at the margin of the patella.
In this way the wire does not invade either the articular or the
subcutaneous surface of the bone (Fig. 137).

Dislocation of the Patella may be due to violence or to
exaggerated muscular action, occurring when the limb is extended
and the tendinous expansions of the vasti are relaxed. The
dislocation is usually over one or other condyle, but occasionally
the bone is twisted round through a right angle so that its
surfaces look medially and laterally. Reduction can only be
effected after complete relaxation of the quadriceps.

FIG. 137. — Diagram to illustrate
how a Fractured Patella may be
wired, without interfering with the
articular surface.

A. Anterior view.

B. Lateral view.

468 THE INFERIOR EXTREMITY

Avulsion of the Tibial Tuberosity occurs in youth before
the completion of ossification (p. 452), and is usually due to
excessive muscular strain. Minor degrees of this accident cause
loosening and partial separation of the tuberosity. If untreated,
the condition may become chronic owing to repeated strains
and want of rest, and it then gives rise to lameness and to pain
and swelling locally (Schlatter's disease).

Dislocation of the Knee-Joint is a somewhat rare injury. In the least
uncommon variety the tibia is displaced forwards and proximally in front
of the femoral condyles. The condition results from violent hyperextension
and the cruciate ligaments are torn, while the posterior ligament is either
ruptured or stripped up with the periosteum on the posterior aspect of the
tibia.

Reduction of this variety is obtained by downward traction on the leg
and direct backward pressure on the proximal extremity of the tibia. If
this method is unsuccessful, hyperextension may be added to the previous
manipulations, but it may result in injuries to the large nerves in the popliteal

In posterior dislocations, which result from direct violence applied either
to the front of the leg or to the back of the thigh, the proximal extremity
of the tibia occupies the popliteal fossa, and may injure or compress the
popliteal vessels.

Ossification of the Head of the Fibula begins about the
third year and forms an epiphysis, which unites with the shaft
between the ages of twenty and twenty-four. Separation of
the proximal epiphysis and fractures of the head or neck of the
fibula are very rare injuries, but when they do occur they are
apt to involve the common peroneal (ext. popliteal) nerve
(p. 446).

When tuberculous disease originates in the fibular diaphysis
near the epiphyseal cartilage, it does not commonly spread to
the proximal tibio-fibular joint, as the epiphyseal cartilage is
entirely extra-capsular (Fig. 132). On the other hand, if the
disease begins in the proximo-lateral part of the tibial diaphysis,
the joint may be infected, as its capsule receives partial attach-
ment to the tibial diaphysis.

THE LEG.

Surface Landmarks. — The medial surface of the tibia is
for the most part covered only by the skin and superficial
fascia, and it can therefore be examined without difficulty.
On the other hand, the shaft of the fibula is clothed with muscles

THE LEG 469

on all sides, and its palpation is by no means easy. The outline
of the bone can best be made out along the posterior intermuscular
septum of the leg, which corresponds to a line drawn from the
posterior part of the head of the fibula to the posterior border
of the lateral malleolus.

When the ankle is actively dorsi-flexed, the muscular belly
of the tibialis anterior forms a prominent elevation on the
anterior aspect of the leg, and its tendon can be traced distally
and medially across the front of the ankle-joint (p. 479). The
flexors of the ankle and extensors of the toes are separated
from the peroneal muscles, which act as evertors of the foot,
by the anterior intermuscular septum of the leg. This septum
corresponds to a line drawn from the anterior aspect of the
fibular head to the anterior margin of the lateral malleolus. In
eversion of the foot the peroneal muscles form a surface elevation
on the lateral aspect of the leg immediately behind the line of
the septum. This elevation is limited posteriorly by a
longitudinal furrow, which marks the position of the posterior
intermuscular septum and separates the peroneal muscles from
the muscles of the calf.

The lateral margin of the soleus is rendered prominent when
the subject stands on tip-toe. It forms a narrow elevation
behind the posterior intermuscular septum, and it disappears
proximally under cover of the gastrocnemius.

The common peroneal nerve can be rolled against the bone, as
it lies first behind the head and then lateral to the neck of the
fibula. Its superficial position and its close relationship to the
bone render the nerve liable to injury from bruising or following
fractures of the fibular neck. It is occasionally divided in
bullet and scythe wounds.

The Deep Fascia of the Leg. — The deep fascia is entirely
absent over the medial surface of the tibia, and it forms a
relatively thin sheet over the posterior aspect of the leg. It
is more strongly developed over the lateral and anterior aspects,
and is specially strong over the proximal part of the tibialis
anterior. The anterior and the posterior intermuscular septa
attach its deep surface to the corresponding borders of the fibula.
In the region of the ankle-joint the deep fascia is strengthened
to form ligamentous bands which retain the various tendons in
position.

The transverse ligament stretches between the anterior borders
of the tibia and fibula immediately proximal to the malleoli.

30 a

470 THE INFERIOR EXTREMITY

The cruciate ligament is made up of two bands, of which one

Tibia, anterior border — j
Tibialis anterior-

Extensor digitoruni longu

Anterior tibial artery-

Peronseus longus-
Peronaeus brevis

Peronaeus tertius

Cruciate ligament

Dorsalis pedis artery
Tendon of tibialis anterior--
Tendon of Peronaeus tertiu
Extensor digitorum brevi
Tendon of Extensor
hallucis longus

--Extensor hallucis longus
•Transverse ligament

FIG. 138. — Muscles and Tendons on the Front of the Leg and Dorsum
of Foot.

extends from the lateral malleolus to the medial margin of the
plantar fascia and the other from the medial malleolus to the

THE LEG 471

upper surface of the calcaneus (p. 478). These ligaments are
split by the tendons of the anterior compartment of the leg.
The transverse ligament possesses two compartments, of which
the medial is occupied by the tibialis anterior and the lateial
by the extensor hallucis longus, the extensor digitorum longus,
and the peronseus tertius. A similar arrangement exists at the
cruciate ligament, with the exception that the extensor hallucis
longus possesses a separate compartment, intermediate in
position between the other two. As the tendons traverse the
ligaments, they are surrounded by synovial sheaths, which
extend for variable distances upon them.

On the medial side of the ankle-joint the deep fascia is
thickened to form the laciniate (internal annular) ligament)
which holds in place the tendons of the tibialis posterior, the
flexor digitorum longus, and the flexor hallucis longus. Synovial
sheaths enclose these tendons, as they lie under the ligament,
and extend forwards along them into the sole of the foot.

Two similar bands are placed on the lateral side of the ankle
in relation to the tendons of the peronaeus longus and brevis.
The superior retinaculum lies behind the lateral malleolus and
possesses a single compartment, lined by a common synovial
sheath. The inferior retinaculum extends from the tip of the
lateral malleolus to the lateral aspect of the calcaneus below
the trochlear process. It possesses two compartments separated
by the process and lined by synovial sheaths which are continuous
with the common sheath under the superior retinaculum.
Either retinaculum may be ruptured by violent contraction
of the peronaei, and the tendons are subsequently easily
displaced.

Anterior Compartment of the Leg. — The Tibialis Anterior arises from
the proximal two-thirds of the lateral surface of the tibia and the adjoining
part of the interosseous membrane. Its tendon runs distally and medially,
passing behind the transverse and cruciate ligaments, to be inserted into the
medial side of the base of the first metatarsal and the adjoining part of the
medial cuneiform. The muscle acts as a flexor of the ankle and an inverter
of the foot. It is supplied by the deep peroneal (ant. tibial) nerve (L. 4, 5,
and S. i).

The Extensor Digitorum Longus, the Extensor Hallucis Longus, and the
Peronceus Tertius arise from the fibula and occupy the lateral part of the
anterior compartment. The former two are inserted into the distal phalanges ;
they flex the ankle-joint and extend the toes. The peronseus tertius is in-
serted into the dorsum of the base of the fifth metatarsal ; it flexes the ankle-
joint and everts the foot. All three are supplied by the deep peroneal (anterior
tibial) nerve (L. 4, 5, and S. i).

The Anterior Tibial Artery arises from the popliteal at the

30 &

472 THE INFERIOR EXTREMITY

distal border of the popliteus, and at once passes forwards
through the proximal part of the interosseous membrane. Its
course corresponds to a line drawn from a point i£ inches lateral
to the tuberosity of the tibia to a second point, situated midway
between the two malleoli. In ligature of the vessel, the incision
is made along this line, and, after the deep fascia has been
divided, the tibialis anterior is retracted medially, and the other
muscles laterally. The artery is then exposed lying on the
interosseous membrane with the deep peroneal nerve either on
its lateral (proximal third) or anterior aspect (middle third).
In the distal third of the leg the artery lies on the tibia, and is
crossed obliquely by the tendon of the extensor hallucis longus.
The deep peroneal nerve again lies to its lateral side.

After ligature of the anterior tibial artery, the circulation
is re-established through the anastomosis around the lateral
malleolus (p. 482) and the connection between the dorsalis pedis
artery and the plantar arch.

The Deep Peroneal (Anterior Tibial) Nerve (L. 4, 5, and
S. i) arises from the common peroneal (external popliteal) on
the lateral aspect of the fibular neck and descends through the
anterior compartment of the leg in close relation to the anterior
tibial artery. It supplies all the muscles in the anterior
compartment and ends in front of the ankle-joint, by dividing
into lateral and medial branches.

The lateral branch supplies the extensor digitorum brevis
and the neighbouring articulations ; the medial branch supplies
the dorsal aspects of the adjacent borders of the first and second
toes.

The Dorsalis Pedis Artery is the direct continuation of
the anterior tibial. It commences midway between the two
malleoli and runs forwards over the talus, navicular, and second
cuneiform bones. At the posterior end of the first inter-
metatarsal space it passes downwards into the sole of the foot
and joins the plantar arterial arch, thus establishing an
important communication between the anterior and posterior
tibial arteries. It is placed very superficially, and its pulsations
can readily be felt on the lateral side of the flexor hallucis longus
tendon.

When the anterior tibial is a small vessel, the dorsalis pedis
may be derived from the perforating branch of the peroneal
artery.

The Superficial Peroneal (Musculo-Cutaneous) Nerve

THE LEG 473

(L. 4, 5, S. i, 2) arises from the common peroneal nerve opposite
the neck of the fibula. It passes forwards between the bone
and the peronaeus longus muscle, and then descends immediately
behind the anterior intermuscular (peroneal) septum. In this
part of its course it supplies branches to the peronseus longus
and brevis muscles. At the junction of the middle and distal
thirds of the anterior intermuscular septum the nerve pierces
the deep fascia and then passes distally and medially across the
extensor tendons. It supplies the skin on the dorsum of the
foot, the medial side of the dorsal aspect of the hallux, and the

j Transverse ligament

Peronreus longus

iceus brevis
Superior retinaculum
Tendo calcaneus

nciate ligament
Extensor digitorum longus

Extensor digitorum brevis
sronseus tertius

Inferior retinaculum | | Peronreus brevis

Trochlear process Perona:us longus

FIG. 139. — The Lateral Aspect of the Ankle and Foot.

adjacent sides of the second, third, fourth, and fifth toes. The
adjacent sides of the first and second toes are supplied by the
medial division of the deep peroneal (anterior tibial) nerve, while
the lateral side of the fifth toe receives branches from the nervus
suralis (p. 446).

The Lateral Compartment of the Leg is occupied by
the Peronseus Longus and Brevis, which both arise from the
lateral aspect of the fibula and pass down behind the lateral
malleolus. In this situation they possess a common synovial
sheath and are kept in place by the superior retinaculum (p. 471).
Below the lateral malleolus the tendons run forwards over the
lateral aspect of the calcaneus, and the brevis passes above and
the longus below the trochlear process. In this situation the

474 THE INFERIOR EXTREMITY

peronsei are retained in place by the inferior retinaculum (p. 471),
and each possesses a synovial sheath, which is continuous
proximally with the common sheath.

The brevis is inserted into the dorsal aspect of the tuberosity
of the fifth metatarsal, and its synovial sheath reaches almost
to the insertion. The longus enters the groove on the plantar
surface of the cuboid and crosses the sole of the foot obliquely
to be inserted into the lateral side of the base of the first
metatarsal and the adjoining part of the medial cuneiform (Fig.
147). In the foot the peronaeus longus is very deeply placed,
and it is surrounded by a synovial sheath which may or may
not be continuous with the sheath which encloses it on the
lateral aspect of the ankle.

Both muscles act as extensors and evertors of the foot, and
they are supplied by the superficial peroneal (musculo-cutaneous)
nerve (L. 4, 5, and S. i).

The tendon sheaths of the peronsei are sometimes the site of
tuberculous disease, and it is important that the condition
should be recognised at an early stage. Otherwise the disease
may spread along the sheath of the longus into the sole of the
foot and infect the tarsal joints. Good exposure is obtained
by a lateral J -shaped incision from behind the lateral malleolus
to the base of the fifth metatarsal. To ensure the complete
removal of the disease, the retinacula must be divided and
their synovial lining dissected away. Thereafter the retinacula
should be reunited over the replaced tendons.

The Posterior Compartment of the Leg.— The muscles
of the posterior compartment consist of a superficial and a deep
group. The superficial group comprises the gastrocnemius,
the plantaris, and the soleus, while the deep group comprises
the flexor hallucis longus, the tibialis posterior, and the flexor
digitorum longus.

The Gastrocnemius arises from the distal part of the femur by two heads
of origin, which are inserted into a common tendon, half-way down the leg.
The Soleus, which lies under cover of the preceding muscle, arises from the
proximal part of the posterior surface of the fibula and by a linear origin from
the popliteal line and the medial border of the tibia. These two muscles
together constitute the Triceps Surse, and their tendons unite to form the
tendo calcaneus (Achillis), which is inserted into the middle part of the posterior
surface of the calcaneus. A small bursa is interposed between the tendon
and the upper part of the posterior surface of the bone. It sometimes becomes
inflamed after excessive walking, and it may be affected in gout or gonorrhoeal
rheumatism.

The Plantaris, which arises close to the lateral head of the gastrocnemius,

THE LEG 475

has a short muscular belly ending in a long, thin tendon, which is inserted into
the calcaneus on the medial side of the tendo calcaneus.

These three muscles receive their nerve-supply from the tibial (internal
popliteal) nerve (L. 4, 5, S. i and 2), and they act as extensors of the ankle-
joint. In addition, the gastrocnemius and plantaris assist in flexing the knee-
joint.

Both the tendo calcaneus and the plantaris tendon may be
ruptured by violent muscular efforts ; in the case of the former
the tendon is exposed by a longitudinal incision, and the torn
ends are sutured together. Occasionally, instead of rupturing,
the tendo calcaneus tears off a fragment from the postero-
superior part of the calcaneus — fracture by avulsion (Fig. 146).
In this case the incision lies along the lateral border of the
tendon and curves forwards along the lateral surface of the
calcaneus. In order to approximate the fragments it may be
necessary to lengthen the tendon, and this may be effected by
a series of hemi-divisions along each border. The fragment is
then screwed into place and the foot is put up in a plaster case,
with the knee flexed and the toes pointed so as to relax the
gastrocnemius and the soleus as far as possible.

The Deep Group of Muscles is separated from the superficial group by
a strong layer of the deep fascia, which extends from the posterior border
of the fibula to the medial border of the tibia.

The Tibialis Posterior arises from the posterior surface of the interosseous
membrane and the adjoining parts of the tibia and fibula. Its tendon passes
distally and medially, and, as it grooves the medial malleolus, passes through
a separate compartment of the laciniate ligament. It is mainly inserted into
the navicular tuberosity ; but, in addition, it sends strong slips to all the
other tarsal bones and to the bases of the middle three metatarsals. These
slips strengthen the plantar ligaments of the foot and assist in maintaining
the longitudinal and transverse arches (p. 492).

The Flexor Digitorum Longus arises from the posterior surface of the
tibia, medial to the tibialis posterior. It inclines slightly laterally as it
descends, and, where it passes through the laciniate ligament, it lies lateral
to the tibialis posterior tendon.

The Flexor Hallucis Longus arises from the posterior surface of the
fibula, lateral to the tibialis posterior. Opposite the ankle-joint it passes
through a separate compartment of the laciniate ligament, being separated
from the flexor digitorum longus tendon by the tibial nerve and the posterior
tibial vessels.

All three muscles are supplied by the tibial nerve (L. 5, S. i and 2). They
act as extensors of the ankle-joint, but, in addition, the tibialis posterior
inverts the foot, while the other two flex the toes.

The Posterior Tibial Artery arises from the popliteal at
the distal border of the popliteus and descends between the
deep muscles and the fascia which covers them. It may be
mapped out on the surface of the limb by a line drawn from the
middle of the popliteal fossa to the mid-point between the

476 THE INFERIOR EXTREMITY

tendo calcaneus and the medial malleolus. The commencement
of the artery is on the same level as the tibial tuberosity. At
first it lies on the tibialis posterior, but near the ankle-joint it
is placed on the tibia between the flexor hallucis longus and the
flexor digitorum longus tendons. It terminates under cover of
the laciniate ligament by dividing into the lateral and medial
plantar arteries.

Ligature of the posterior tibial artery is usually carried out
from the medial side, in order to avoid injuring the superficial
group of muscles. The incision is made a finger's breadth
behind the medial border of the tibia in its proximal third, and
retraction of the skin and fasciae exposes the free border of the
medial head of the gastrocnemius, which overlaps the origin of
the soleus from the medial border of the tibia (p. 474). The
wound is deepened through the soleus, exposing the strong
fascia which covers the deep muscles. After this fascia has been
carefully split, its lateral part is raised from the underlying
muscles, and the posterior tibial artery with its venae comites
is exposed, lying on the tibialis posterior. In the proximal third
of the leg the tibial nerve lies close to the medial side of the
artery, and must be avoided when the ligature is applied.

The Tibial Nerve passes distally through the posterior
compartment in close relation to the posterior tibial vessels.
At first it lies on their medial side, but as it descends it crosses
them superficially and lies on their lateral side at the ankle.
It gives off branches of supply to the deep muscles (p. 475) and
terminates under the laciniate ligament by dividing into the
lateral and medial plantar nerves.

The Peroneal Artery arises from the posterior tibial soon after its com-
mencement and runs distally in association with the flexor hallucis longus.
It lies to the lateral side of the posterior tibial artery and, just proximal to
the ankle-joint, gives off a perforating branch which pierces the interosseous
membrane and descends in front of the lateral malleolus.

The Surgical Approach to the Tibia, whether for
exploration or for resection, is carried out along the medial
surface of the bone. The incision is vertical and is carried down
to the periosteum, care being taken to avoid injuring the
saphenous nerve and the great saphenous vein as they lie in
front of the medial malleolus. Resection of the whole diaphysis,
or of a portion of it, may be carried out in the manner already
described in the case of the humerus (p. 39). Along the
interosseous crest and near the epiphyseal cartilages the
periosteum is more adherent than it is elsewhere, and it is

THE REGION OF THE ANKLE AND FOOT 477

consequently more liable to injury in these areas. When the
epiphyseal cartilage is affected and it is feared that shortening
of the tibia will result, subsequent inversion of the foot may be
obviated by fracturing the fibula and allowing the ends to
overlap.

In the Surgical Approach to the Fibula the incisions
are planned to avoid injuring the superficial peroneal (musculo-
cutaneous) nerve. Subperiosteal resection of the proximal or
middle thirds is carried out through an incision along the line
of the posterior intermuscular septum. In the proximal third
the wound is deepened between the adjoining borders of the
soleus and the peronseus longus, and care must be taken not
to injure the common peroneal nerve as it winds round the
fibular neck.

In the middle third, the incision exposes the peronseus longus
in front and the flexor hallucis longus behind, the latter muscle
projecting from under cover of the lateral border of the soleus.

In the distal third, the incision lies just posterior to the anterior
intermuscular septum, and the periosteum is divided between
the peronseus brevis and the peronseus tertius.

Fractures of the Leg may involve one or both bones.
When only one bone is fractured there is little displacement,
and the sound bone acts as a satisfactory support.

Both bones may be fractured as the result of direct or indirect
violence. In the former case the fractures are transverse and
occur at the same level in both bones. In indirect violence the
bones give way at different levels, the tibia at the junction of its
middle and distal thirds, and the fibula at the junction of its
middle and proximal thirds. When displacement occurs, it is
due to the powerful triceps suras, which draws the distal
fragments upwards behind the proximal fragments and often
causes some degree of anterior angulation.

As the medial surface of the tibia is covered only by skin
and superficial fascia, fractures of this bone are not uncommonly
compound.

THE REGION OF THE ANKLE AND FOOT.

Surface Landmarks.— The twomalleoli serve as important
guides to the surgeon in operations in the region of the ankle-
joint. The lateral malleolus is the larger of the two, and its tip

478

THE INFERIOR EXTREMITY

lies a quarter of an inch distal and three-quarters of an inch
posterior to the tip of the medial malleolus. The trochlear
process (peroneal tubercle) of the calcaneus can usually be felt
one finger's breadth below the lateral malleolus, but it is some-
times too small to be identified. When the foot is actively
everted the tendons of the peroncei, longus and brevis, can be
made out as they pass respectively above and below the
trochlear Drocess.

Calcaneus
Trochlear proce

Tuberosity of fifth metatarsal
Cuboid

FIG. 140. — The Bony Landmarks on the Lateral Aspect of the Ankle
and Foot.

In active flexion of the ankle the extensor digitorum brevis
produces an elevation on the lateral part of the dorsal aspect of
the foot, and, when the muscle is relaxed, pseudo-fluctuation
can be obtained by palpating it transversely. The posterior
part of the muscle overlies the calcaneo- cuboid joint (p. 484),
and behind the joint the anterior part of the upper surface of
the calcaneus can readily be distinguished.

The tuberosity on the base of the fifth metatarsal, which lies
three fingers' breadths in front of the lateral malleolus, forms
a prominent landmark on the lateral border of the foot. It

THE REGION OF THE ANKLE AND FOOT 479

should be remembered that the tuberosity projects in a backward
direction, and that, on this account, in disarticulations (Key's
and Lisfranc's) at the tarso-metatarsal joint the knife, entered
on the lateral side, must be carried forwards and medially.

When the ankle is actively flexed with the toes extended
(dorsi-flexed), the tendons of the extensor longus digitorwn and
halluds are rendered very prominent, as the skin and superficial
fascia on the dorsum of the foot are thin and the deep fascia is
not specially thickened except in certain situations. When the

Navicular tuberosity
First metatarso-cuneiform joint

FIG. 141. — The Surface Landmarks on the Medial Side of the Ankle
and Foot.

flexed foot is actively inverted, the tendon of the tibialis anterior
can be traced downwards across the medial part of the anterior
surface of the ankle-joint to its insertion into the first metatarsal
and the adjoining cuneiform bone (p. 469) on the medial side
of the foot.

The sustentaculum tali lies one finger's breadth below the
medial malleolus, and it is slightly obscured by the flexor
digitorum longus tendon, which crosses its medial aspect. The
tendon of the flexor hallucis longus grooves the plantar surface
of the sustentaculum. The tuberosity of the navicular lies rather
more than one inch in front of the sustentaculum tali, and the
interval between the two is occupied by the head of the talus
(astragalus). This interval is increased in flat-foot by the

480 THE INFERIOR EXTREMITY

downward displacement of the head of the talus, which may
sometimes form a visible prominence, but it is correspondingly
diminished in talipes varus (p. 495). The prominent ridge on
the base of the first metatarsal can be felt at a point i J inches in
front of the navicular tuberosity.

The first metatarso-phalangeal joint lies a little in front of the
centre of the ball of the great toe, while the others are placed
one inch behind the web of the toes.

FIG. 142. — Normal Ankle-joint of Child, aged fourteen. Antero-posterior
view. Observe the levels of the epiphyseal lines of the tibia and fibula.

The level of the ankle-joint can be made out when the foot is
passively flexed and extended alternately, as the anterior border
of the distal extremity of the tibia is easily felt. When the foot
is extended, the anterior part of the upper surface of the body
of the talus projects beyond the tibia and can be examined
immediately distal to it. The head of the talus can be felt three-
quarters of an inch above and behind the navicular tuberosity.

In effusions into the ankle-joint the extensor tendons are
elevated by the distended capsule, and the depressions on each
side of the tendo calcaneus (Achillis) become occluded.

THE REGION OF THE ANKLE AND FOOT 481

Ossification of the Distal Extremities of the Bones of
the Leg. — Secondary centres appear in the cartilaginous distal
extremities of the tibia and fibula about the second year, and
the epiphyses so formed unite with the diaphysis during the
nineteenth year.

As the fibula projects distally beyond the tibia, the epiphyseal
lines of the two bones are situated at different levels so that the
distal extremity of the fibular diaphysis is in relation to the
tibial epiphysis (Fig. 142), and therefore to the joint-cavity —
when present (p. 482) — of the distal tibio-fibular articulation.
The fibular diaphysis is sometimes intra-capsular in relation
to the ankle-joint.

The Ankle- Joint. — At this joint the talus articulates with
the tibia by its superior surface and with the malleoli on each
side. The necessary stability is obtained by the downward
projection of the malleoli, which descend on each side of the
talus and only permit a slight degree of lateral movement. The
upper surface of the talus is wider in front than it is behind, and
on this account, side to side movements at the ankle-joint occur
more freely when the foot is extended than when it is flexed.

The Capsule of the ankle is relatively weak. Proximally,
it is attached to the fibular and tibial epiphyses around the
margins of their articular surfaces. Distally, it is attached
around the articular surface of the talus except on the anterior
aspect of the joint, where it extends on to the neck of the bone
(Fig. 144); which is thus in part intra-capsular.

The synovial membrane lines the interior of the capsule, and
anteriorly it is reflected over the intra-capsular part of the neck
of the talus.

The anterior and posterior ligaments of the ankle are special
thickenings of the capsule which require no detailed description.
The Deltoid Ligament strengthens the medial part of the
capsule. It is narrow at its proximal attachment to the medial
malleolus, but widens out distally and is attached not only to
the talus but also to the sustentaculum tali, the plantar calcaneo-
navicular (" spring ") ligament and the navicular bone.

The Lateral Ligament consists of three separate bands,
(i) The anterior talo-fibular ligament stretches from the anterior
border of the lateral malleolus to the lateral side of the body
of the talus. (2) The calcaneo-Jibular ligament is a cord -like
band which extends from the tip of the malleolus to the lateral
surface of the calcaneus. (3) The posterior talo-fibular ligament

482

THE INFERIOR EXTREMITY

passes transversely from a depression on the medial aspect of
the lateral malleolus to the posterior process (tubercle) of the
talus (Fig. 143).

The Distal Tibio-Fibular Joint is usually a syndesmosis

and permits of practic-
ally no movement. The
two bones are connected
by a strong interrosseous
ligament and by the
inferior transverse liga-
ment, which extends
from the depression on
the posterior part of
the medial surface of the
lateral malleolus to the
posterior border of
the distal extremity of
the tibia. Occasionally,
however, there is a
joint-cavity, which com-
municates freely with
the cavity of the ankle-
joint.

Anastomosis round
the Ankle. — An import-

FIG. 143. — Frontal Section through the Ankle-
joint, the Tibio-Fibular Syndesmosis, the ant anastomosis OCCUrs
Talo-Calcaneal and the Talo-Calcaneo- ,, • r ,,

in the region of the

Navicular Joints. The deltoid ligament, m L1Jf ,

on the medial side, and the posterior talo- ankle-joint. Around the

fibular and the calcaneo-fibular ligaments, lateral malleolus the ter-
on the lateral side are shown in the section. 7 -, , f ..

The strong interosseous talo-calcaneanliga- mmal and Pirating

ment is seen forming the lateral boundary branches of the peroneal

of the joint between the head of the talus anastomose with the
and the sustentaculum tali. The positions
of the distal epiphyseal lines of the tibia
and fibula should be observed.

lateral malleolar branch
•of the anterior tibial
and the lateral tarsal
branch of the dorsalis
pedis. On the medial
side of the ankle the
medial malleolar branch of the anterior tibial anastomoses with
the medial calcanean branches of the lateral plantar artery.

Spread of Tuberculous Disease in the Ankle Region.—
When tuberculous disease originates in the distal end of the

Light blue = articular cartilage.
Striped blue = ligaments.
Green = periosteum.
Red = synovial membrane.

THE REGION OF THE ANKLE AND FOOT 483

diaphysis of the tibia, it is entirely extra-capsular and extra-
synovial (Fig. 143), and, on this account, the ankle-joint is
rarely involved. The disease commonly spreads along the
diaphysis, producing diffuse osteo-myelitis, or it may spread
towards the surface of the bone, perforate the periosteum, and
affect the soft parts.

Tuberculous disease originating in the distal end of the
fibular diaphysis spreads in a precisely similar manner, but the

Flexor hallucis
longus

Pad of fat

FIG. 144. — Sagittal Section of Foot, showing some of the Articulations.
The synovial membranes are shown in red.

1. Flexor hallucis longus.

2. Plantar accessory :netatarso-phal-

angeal ligament.

3. Sesamoid bone.

4. Flexor hallucis brevis.

5. Plantar aponeurosis.

6. Flexor digitorum brevis.

7. Tibialis posterior tendon.

8. Flexor digitorum longus tendon.

9. Plantar calcaneo - navicular liga-

ment.

10. Quadratus plantae.

11. Lateral plantar vessels and nerve.

12. Calcaneus.

ankle-joint may be infected when the fibular diaphysis is
intra-capsular (p. 481).

When the disease commences in the neck of the talus, it may
spread (i) upwards, when it at once involves the synovial
membrane of the ankle-joint ; (2) backwards, so as to infect
the body of the bone, whence it spreads through the articular
cartilage, either upwards to the ankle-joint or downwards to
the talo-calcanean joint ; (3) forwards, so as to infect the talo-
calcaneo-navicular joint (Fig. 144).

The Joints of the Foot. — The Talo-Calcanean Joint
lies immediately below the ankle-joint and possesses a separate

31 a

484 THE INFERIOR EXTREMITY

synovial membrane. At this joint the inferior surface of the
body of the talus articulates with the upper surface of the
calcaneus (Fig. 144).

The Talo-Calcaneo-Navicular Joint is formed by the head
of the talus,, the posterior surface of the navicular and the upper
surface of the sustentaculum tali. This large joint -cavity,
which is lined by a single synovial membrane, is closed infero-
medially by the plantar calcaneo-navicular ligament, and is shut
off from the talo-calcanean joint by the strong interosseous talo-
calcanean ligament.

The -plantar calcaneo-navicular (" spring ") ligament stretches
from the anterior border of the sustentaculum tali to the plantar
surface of the navicular. It is of great strength so as to enable
it to support the head of the talus and the part of the body-
weight which it transmits.

The Calcaneo - Cuboid Joint lies midway between the
lateral malleolus and the base of the fifth metatarsal. It is
provided with a separate synovial membrane and is supported
inferiorly by the short and long plantar ligaments.

In Chopart's amputation at the " transverse tarsal " joint,
the talo-navicular and calcaneo-cuboid joints are cut through.
On the medial side, the knife is inserted behind the navicular
tuberosity and is carried forwards and laterally, following the
convexity of the head of the talus. On the lateral side the
knife is inserted midway between the lateral malleolus and the
base of the fifth metatarsal, and is carried backwards and
medially, following the line of the calcaneo-cuboid joint. This
operation does not secure a good bearing surface, as the talus,
which is no longer supported by the plantar calcaneo-navicular
ligament, is tilted forwards by the weight of the trunk and the
calcaneus is correspondingly tilted upwards posteriorly, despite
division of the tendo calcaneus.

The joint between the medial cuneiform and the first metatarsal
possesses a separate joint cavity, but the remaining inter-tarsal,
tarso-metatarsal, and inter-metatarsal joints are frequently
lined by the prolongations of a single synovial membrane.

In the amputations of Hey and Lisfranc, the foot is
disarticulated at the tarso-metatarsal articulation. The line
of the articulation passes medially and slightly forwards across
the foot from the lateral side. When the knife is inserted
behind the tuberosity of the fifth metatarsal, it must be carried
forwards for a short distance before the joint cavity is opened,

THE REGION OF THE ANKLE AND FOOT 485

and it can then be carried medially and slightly forwards in the
line of the joints until the second metatarsal is encountered.
The base of the second metatarsal projects backwards between
the medial and lateral cuneiforms, and consequently the line of
its articulation with the second cuneiform is posterior to the
other tarso -metatarsal joints. The knife is then inserted on
the medial side of the foot just behind the base of the first
metatarsal, and is carried laterally and slightly backwards
through the first joint until it is again obstructed by the base
of the second metatarsal. After division of the dorsal cuneo-
metatarsal ligaments, an attempt is made to flex the metatarsus
on the tarsus. This process puts on the stretch the strong
interosseous ligaments which connect the base of the second
metatarsal to the medial and lateral cuneiforms, and after they
have been divided by cutting backwards, the disarticulation
may be completed by cutting through the plantar cuneo-
metatarsal ligaments. Instead of disarticulation, the base of
the second metatarsal may be sawn across ; or the medial
cuneiform may be sawn through on a level with the second
cuneo-metatarsal joint, and the base of the second metatarsal
can then be disarticulated by division of the strong interrosseous
ligament which connects it to the lateral cuneiform bone.

The intertarsal or tarso-metatarsal joints may be infected
with tuberculous disease from a focus in one of the tarsal or
metatarsal bones, as the disease requires to erode only the
articular cartilage.

Injuries in the Region of the Ankle - Joint.—
Injuries in this region commonly follow falls or twists in which
the weight of the body is transmitted along a line which is
either lateral or medial to the usual axis (p. 463). As a result
the foot is over-inverted or over-everted, and a slight degree of
adduction or abduction may be present. The precise nature
of the injury will depend on the position into which the foot is
forced by the violence, but it must be remembered that, in
children, a diastasis may occur instead of a fracture. These
injuries almost always involve the ankle-joint, and the consequent
swelling tends to obscure the subcutaneous bony points.

Sprains of the Ankle usually occur following over-inversion
of the foot. The anterior talo-fibular and sometimes the
calcaneo-fibular ligaments (anterior and middle fasciculi of the
external lateral ligament) are torn, and in severe cases the
anterior part of the capsule also is ruptured. Tenderness is

31 b

486 THE INFERIOR EXTREMITY

experienced on palpation over the attachments of these ligaments
(p. 481) but no pain is elicited on examination of the subcutaneous
surface of the fibula. Swelling and discoloration are often
more marked than they are when a fracture is present.

A somewhat similar condition results from over-eversion of
the foot, but in this case tenderness is experienced over the
attachments of the deltoid ligament (p. 481).

Pott's Fracture. — Fracture of the distal part of the fibula
is a common accident, as the region is frequently subjected to
violence, and the ligaments of the tibio-fibular syndesmosis
(p. 482) are stronger than the bone. The term " Pott's Fracture"
includes two distinct varieties of injury : (a) fracture of the
distal part of the fibula together with injury of the deltoid
ligament or medial malleolus, and (b) fractures of the distal
extremity of the tibia, together with tearing of the lateral
ligament of the ankle or fracture of the lateral malleolus.

(a) In violent eversion of the foot, the deltoid (internal
lateral) ligament is overstretched and may either give way or
tear off the medial malleolus. In children, a diastasis of the
tibial epiphysis may result. If the violence continues to act
the lower part of the lateral surface of the talus is forced against
the lateral malleolus and the distal part of the fibular shaft gives
way, unless the powerful ligaments of the distal tibio-fibular
joint are torn through. The latter condition does occasionally
occur, and is indicated by a great increase in the width of the
ankle. In these circumstances the talus may be dislocated
upwards between the tibia and fibula (Dupuytren's fracture).

(b) In violent inversion of the foot, the upper part of the
lateral surface of the talus is tilted laterally and downwards
against the lateral malleolus and the lateral ligament gives way,
or the fibula fractures proximal to the tibio - fibular joint.
Continuance of the violence forces the medial surface of the
talus upwards and medially against the medial malleolus, which
gives way, often breaking off an irregular fragment from the
distal extremity of the tibia.

Fractures in this region may be associated with incomplete
dislocations of the foot.

Dislocation of the Talus is rare and is often compound.

When deformities in this region are being corrected, the
knee should be passively flexed to relax the tension of the
muscles of the calf. Subsequently the foot should be kept at
right angles, for in this position the widest part of the talus

THE REGION OF THE ANKLE AND FOOT 487

occupies the interval between the two malleoli, and contracture
of the tendo calcaneus is unlikely to occur. It is wiser to err
on the side of inversion rather than eversion, as in the latter
case flat-foot may subsequently develop, and to avoid this
sequela, care must be exercised to see that the medial margin
of the hallux, the medial malleolus and the medial border of the
patella are all in the same straight line.

Surgical Approach to the Ankle - Joint. — In
arthrotomy, arthrodesis, excision of the joint or removal of the
talus, the best approach is obtained by means of Kocher's lateral
J-shaped incision, with or without some slight modification.
This incision begins behind the fibula and extends below the
lateral malleolus to the trochlear process (peroneal tubercle),
being placed above the nervus suralis and the small saphenous
vein. From this point it curves gently forwards to end a little
behind the insertion of the peronseus tertius (p. 471). The flap
thus outlined, which consists of skin, fascia and periosteum of
the lateral malleolus, is dissected forwards off the peronaei and
the malleolus, while below, after division of the cruciate ligament,
it is dissected off the anterior talo-fibular ligament (p. 481), the
anterior ligament of the ankle and the extensor digitorum
brevis. The whole flap is then retracted to the medial side
together with the extensor tendons. After the retinacula have
been split and the peroneal tendons divided, the three parts of
the lateral ligament of the ankle (p. 481), and the weak anterior
and posterior ligaments are cut through and the foot is forcibly
dislocated by over-inversion. During this process the medial
malleolus may break, but this accident is unimportant, as the
deltoid ligament remains intact and the surfaces can subsequently
be re-opposed.

By this method, a complete view of the interior of the joint
is obtained, and the diseased synovial membrane can be entirely
removed along with the anterior and posterior ligaments, but
care must be taken not to injure the anterior or posterior tibial
arteries as they lie in relation to the joint (pp. 472 and 476).

Excision of the Talus. — If the arthrotomy shows that the
disease originated in the talus, this bone may be excised
completely. The posterior part of the extensor digitorum
brevis is elevated, and the talo-navicular joint is opened. The
head of the talus can be drawn upwards, and when the talo-
calcanean interosseous ligament is cut through, the bone is
held only by the attachment of the deltoid ligament to its medial

488 THE INFERIOR EXTREMITY

surface (p. 481). The removal of the talus opens both the
talo-calcanean and the talo-calcaneo-navicular joint-cavities,
and if the synovial membrane which lines them is infected, it
must be removed.

After excision of the talus, the sustentaculum tali may be
removed^ and the calcaneus may be further trimmed till it can
be fitted in between the malleoli. When this is carried out, the
lateral malleolus projects too far, and therefore requires to be
shortened.

Before the wound is finally closed, the peroneal tendons are
sutured, and the retinacula are stitched over them again.

Arthrodesis of the Ankle - Joint is rarely followed by
completely satisfactory results, because the necessary removal
of the articular cartilage decreases the size of the talus while
increasing the size of the cavity into which it is to be received.
This disadvantage may be minimised by inserting a large nail
in an upward direction through the calcaneus and talus into
the tibia, the foot meanwhile being maintained at right angles ;
when the nail is removed at the end of three weeks, the limb is
put up in a plaster case.

The Calcaneus (Os Calcis). — Tuberculous disease may not
infrequently originate in the body of the calcaneus close to the
epiphyseal line, and may spread (i) upwards and forwards, to
penetrate the articular cartilage and infect the talo-calcanean
joint ; (2) medially, through the periosteum to infect the
synovial sheaths of the tendons of the tibialis posterior, etc.
(p. 475) ; (3) laterally, through the periosteum, to infect the
peroneal tendon sheaths (p. 473). Early recognition by
radiograms is important in order that these complications may
be prevented.

The surgical approach to the calcaneus is obtained by means,
of a lateral or a medial flap operation. The incisionjies below
the level of the tendons and the flap includes all the soft parts
and the periosteum. In the child, since the body of the bone
is not completely ossified, a thin layer of its cartilaginous surface
is elevated with the periosteum. The focus may then be gouged
out and the flap replaced.

In more advanced cases, where freer access is desired, the
incision begins behind the tuberosity of the fifth meiatarsal
and, passing backwards round the heel below the tendo calcaneus,
ends on the medial aspect slightly in front of the medial malleolus.
A large flap, consisting of soft parts, periosteum, and cartilage,

THE REGION OF THE ANKLE AND FOOT 489

can then be turned down from the lateral, posterior, and medial
aspects of the calcaneus.

Ossification of the Tarsus. — At birth, ossific centres are
present in the calcaneus, the talus and the cuboid. The lateral
cuneiform begins to ossify during the first year, the middle
cuneiform during the second year, and the medial cuneiform

FIG. 145. — Normal Ankle-joint. Lateral View.
calcanean epiphysis.

Observe the

and the navicular during the third or fourth year. A secondary
centre appears in the cartilaginous posterior extremity of the
calcaneus during the eighth year, and forms an epiphysis which
unites with the body of the bone between the ages of sixteen and
twenty. A separate centre for the posterior process (external
tubercle) of the talus is sometimes present, and it may remain
separate, being then known as the os trigonum (Fig. 146).

Fractures of the tarsal bones may occur when the patient,

490

THE INFERIOR EXTREMITY

after falling from a height, lands upon his feet. They commonly
involve either the talus or the calcaneus.

The neck of the talus may be fractured transversely, or the
body of the bone may be crushed between the calcaneus and

FIG. 146. — Avulsion Fracture of the Calcaneus. The fragment has been
fixed in position with a screw. Note the increased density of the shadow
caused by the superimposed lateral malleolus. It partially obscures the
os trigonum tarsi, which is present in this case.

the' tibia. The condition is always accompanied by considerable
limitation of movement at the ankle-joint.

Fracture of -the calcaneus, which is the commonest fracture
of the tarsus, is usually comminuted and is often bilateral. If
there is little comminution, the fracture may be overlooked,
unless X-rays are employed, as the collateral ligaments of the
ankle and the tendons in relation to the calcaneus retain the

THE REGION OF THE ANKLE AND FOOT 491

fragments in fair position. It is important that the injury
should be recognised since flat-foot may result unless proper
treatment is carried out. When the fragments have been moulded
into position, the foot is put up at right angles and slightly
inverted.

Fracture of the sustentaculum tali and avulsion of the postero-
superior part of the calcaneus are rare injuries (Fig. 146).

In the examination of radiograms of the tarsus, the presence
of the calcanean epiphysis and the occasional os trigonum
(p. 489) must be borne in mind.

Fractures of the metatarsals are difficult to recognise as the
oedema may be considerable, and there is little or no displace-
ment, owing to the way in which the bones are bound together
in the transverse arch of the foot. The prominent base of the
fifth metatarsal may be fractured when the patient falls heavily
on the inverted foot (Jones).

The Deep Fascia of the sole of the foot is termed the plantar aponeurosis.
Like the palmar aponeurosis (p. 82), it consists of a strong central and two
weak collateral parts. The central portion is attached posteriorly to the
calcanean tuberosity, and anteriorly it divides into five slips, which are
connected to the fibrous flexor sheaths of the toes (cf. palm of hand, p. 83).
It is the central portion of the plantar aponeurosis, which normally helps to
support the longitudinal arch of the foot, and it is much shortened in pes
cavus and in some of the varieties of talipes.

The weak, medial part of the plantar aponeurosis covers the abductor
hallucis, which extends from the calcanean tuberosity to the medial side of
the base of the first phalanx of the hallux.

Owing to the density of the central part of the plantar aponeurosis,
swelling first becomes apparent on the dorsum of the foot in inflammatory
conditions of the sole or of the articulations (cf. palm of hand, p. 82).

The small muscles of the sole of the foot are of less importance than the
corresponding muscles in the palm of the hand, as the foot is primarily
required to be a stable support for the body weight, and the movements of
the individual toes, therefore, are of less consequence.

The medial plantar nerve (L. 4, 5, and S. i) arises from the tibial nerve
under cover of the laciniate ligament (p. 471), and runs forwards with the
medial plantar artery. It corresponds to the median nerve in the palm of
the hand, and, though it supplies few muscles, it supplies a large cutaneous
area, including the plantar aspects of the medial three toes and the tibial
side of the fourth toe.

The lateral plantar nerve (S. i and 2) corresponds to the ulnar nerve in
the palm of the hand (p. 85). It arises from the tibial nerve under cover
of the laciniate ligament, and accompanies the lateral plantar artery and the
plantar arch. It supplies most of the muscles of the sole, the skin of the
lateral part of the sole, and the plantar aspects of the fifth toe and the fibular
side of the fourth toe

At the distal border of the laciniate ligament the posterior tibial artery
divides into the lateral and medial plantar arteries. The medial plantar,
which is usually a small vessel, passes forwards between the abductor hallucis

492 THE INFERIOR EXTREMITY

and the flexor digitorum brevis, and its terminal branches join the digital
arteries.

The lateral plantar artery runs forwards and laterally towards the base of
the fifth metatarsal, where it bends sharply medially, and becomes the plantar
arch. The arch lies on the bases of the middle three metatarsals, and is
completed at the posterior end of the first inter-metatarsal space, where it
is joined by the dorsalis pedis artery.

Gangrene of the Foot. — When senile gangrene is due to
gradual obliteration of the small arteries of the foot, it begins
at the periphery and spreads in a proximal direction. The
pathological process tends to be delayed, and may even come
to a sudden stop, on the distal side of the large joints. The
position of these lines of demarcation is determined by the
anastomoses, which occur round the ankle (p. 482), the knee
(p. 445), and the hip (pp. 416 and 418).

On the other hand, when gangrene is due to obstruction of
one of the main arterial trunks by an embolus, its onset is sudden
and a large area is rapidly involved.

The Architecture of the Foot is so planned that the
weight of the body may be equally distributed over the bearing
surface. Under normal conditions the foot forms a tripod,
the points of which are the calcaneus and the heads of the first
and fifth metatarsal bones. To a much lesser extent, the heads
of the middle three metatarsals and the lateral border of the
foot help to support the body-weight. This arrangement is
maintained by the presence of two intersecting arches, of which
one is longitudinal and the other transverse. Each is supported
by ligaments, muscles and tendons, which render it somewhat
elastic. On this account the arches flatten out slightly when
the weight of the body is borne upon the feet and contract again
as soon as the weight is removed.

The Longitudinal Arch is constituted by the medial border
of the foot, and its keystone is formed by the head of the talus.
The short posterior limb of the arch is formed by the calcaneus,
while the navicular, cuneiforms, and medial three metatarsals
constitute the longer anterior limb. The head of the talus is
supported by the plantar calcaneo- navicular ("spring")
ligament, which extends between the sustentaculum tali and
the navicular (Fig. 144). This ligament is supported, in its
turn, by the strong tendons of the tibialis posterior, the flexor
digitorum longus and the flexor hallucis longus, which are
related to its medial border and plantar aspect. The two flexor
tendons cross one another in the region of the plantar calcaneo-

THE REGION OF THE ANKLE AND FOOT 493

navicular ligament and the tendinous sling which they form
renders additional support. Further the longitudinal arch
is strengthened by the plantar aponeurosis and the abductor
hallucis, which connect the bases of its two limbs (Fig. 144).

The principal Transverse Arch is placed at the level of the
distal row of the tarsus and the bases of the metatarsal bones.
It is maintained by the plantar inter-tarsal and tarso-metatarsal
ligaments,, while the tendon of the peronseus longus stretches
across the arch like a bow-string and serves to approximate its
extremities (Fig. 147). Additional support is obtained from the
tendinous sling formed by the crossing of the flexor longus

Second cuneiform
Dorsalis pedis a.
First cuneiform I

Third cuneiform

Fibrous sheath of peronaeus longus
Peronaus longus tendon

Cuboid

Abductor
digiti quinti

i Lateral plantar a.

Abductor hallucis | I | Lateral plantar n.

Flexor hallucis brevis | Quadratus plantae

Flexor hallucis longus tendon Flexor digitorum brevis

Medial plantar a. | Flexor digitorum longus tendon
Medial plantar n.

FIG. 147. — Transverse Section through the Foot, to show the Transverse
Arch of the Foot and the Peronaeus Longus Tendon.

digitorum and hallucis tendons, and from the additional slips
of insertion of the tibialis posterior (p. 475), which tend to
contract the arch.

Fiat-Foot. — Loss of tone in the muscles which support the
arches of the foot throws an increased strain upon the supporting
ligaments and constitutes the first stage in the development of
flat-foot. At this period treatment must be directed to the
weakened muscles, or the ligaments will gradually stretch,
giving rise to pain and aching over their attachments. In the
second stage both arches give way, the longitudinal flattening
being the more noticeable. The head of the talus sinks
downwards, forwards and medially so as to increase the interval
between the navicular tuberosity and the sustentaculum tali ;

494 THE INFERIOR EXTREMITY

and produces a prominence on the medial border of the foot in
front of the medial malleolus. The downward displacement
of the talus is accompanied by lateral deviation of the foot,
and the body-weight is carried on the collapsed longitudinal
arch.

Deformities of the Foot.— Talipes may be either a
congenital or an acquired deformity and may affect one or both
feet. In Congenital Talipes the foot develops in the faulty
attitude and the bones are therefore modified in shape, while
some of the soft structures are lengthened and others are
shortened. In Acquired Talipes, which usually results from
acute anterior poliomyelitis and occasionally from cerebral
palsy or nerve injuries, the attitude of the foot depends on the
over-action of some muscle or muscles following parsesis or
paralysis and atrophy of its antagonists.

Four primary deformities are recognised: (i) Talipes Equinus,
in which the heel is raised and the toes are pointed ; (2) Talipes
Calcaneus, in which the foot is dorsi-flexed and the long axis
of the calcaneus becomes nearly vertical ; (3) Talipes Varus,
in which the foot is inverted ; (4) Talipes Valgus, in which the
foot is everted. Combinations of these primary deformities
may occur, including Talipes Equino-varus — by far the
commonest of all the varieties of talipes — Equino-valgus,
Calcaneo-varus and Calcaneo-valgus.

(1) Talipes Equinus. — When the condition is congenital,
the muscles of the posterior compartment of the leg and the
plantar aponeurosis are shortened secondarily to the faulty
position. When the condition is acquired, it is caused by the
tonus of the muscles of the posterior compartment, which are
unopposed owing to paralysis or parsesis of the muscles of the
anterior compartment of the leg. All the anterior muscles are
not necessarily involved and one or more of them may escape.

(2) Talipes Calcaneus. — When the condition is congenital,
the tendons of the muscles of the anterior compartment of the
leg are shortened, while the muscles of the posterior compartment
are overstretched. When the condition is acquired, it is caused
by the tonus of the muscles of the anterior compartment, which
are unopposed owing to paralysis of the posterior muscles. As
in the other varieties of acquired talipes, the degree of the
deformity depends on the extent of the paralysis, the condition
being most marked when both the superficial and the deep
muscles are affected.

THE REGION OF THE ANKLE AND FOOT 495

(3) Talipes Yarns. — When the condition is congenital, the
tendons of the tibialis anterior and posterior are shortened, and
the distal part of the tibial diaphysis is twisted slightly in a
medial direction. When the condition is acquired, it results
from the tonus of the tibialis anterior following paralysis of the
peronaeus longus or brevis, or of both these muscles.

(4) Talipes Valgus. — In the congenital variety the peronsei,
longus, brevis, and tertius, are shortened while the two tibiales
are overstretched. The acquired variety is due to paralysis
of both the tibialis anterior and the tibialis posterior.

In the combined varieties, the muscles of more than one
compartment are involved. Thus, in acquired talipes equino-
varus, the peronsei are affected together with one or more
muscles of the anterior compartment. The highest degree of
the deformity is produced when all the muscles of both com-
partments are paralysed.

In congenital talipes, the treatment should be based on the
degree of the deformity. In minor deformities, methodical
manipulations, which tend to overcorrect the faulty position,
and possibly the use of a light splint, may be sufficient. When
the deformity is more pronounced, the manipulations must be
more vigorous, and tenotomy of the shortened structures
may be necessary before the foot can be wrenched into better
position. In the worst cases operative interference, such as
excision of the talus or the removal of a wedge-shaped portion
from the tarsus (cuneiform tarsectomy), alone will produce
correct alignment.

Cuneiform Tarsectomy. — The position of the wedge of
bone removed in cuneiform tarsectomy depends on the nature
of the deformity. In talipes equino-varus , the base of the wedge
is on the lateral border of the foot. The incision, which divides
the nervus suralis and the small saphenous vein, is carried
backwards and laterally from the prominent head of the talus
to the calcaneus. The skin and fasciae are undercut, and this
step exposes the medially displaced extensor tendons at the
medial extremity of the wound and the extensor digitorum
brevis at the lateral extremity. The lateral part of the cruciate
ligament (p. 470) is divided and turned medially, together with
the extensor digitorum brevis, which is elevated from the
calcaneus. The extensor tendons are retracted, and a sharp
gouge is thrust horizontally through the lateral surface of the
calcaneus into the talo-navicular joint. The gouge is next

496

THE INFERIOR EXTREMITY

inserted at the cubo-metatarsal joint and carried medially
through the cuneiform bones to the medial border of the foot.
Thereafter the wedge is removed; and if sufficient bone has been
resected, the two portions of the foot can be brought together
without any stretching of soft parts.

In order to correct the " in-toeing/' the abductor hallucis
(p. 491) may be excised through a linear incision on the medial
side of the foot. Division or lengthening of the tendo calcaneus
(p. 475) completes the operation.

It must be remembered that many of the muscles which are
involved at first in acute anterior poliomyelitis may subsequently
recover; and on this account steps must be taken to prevent
the temporarily paralysed muscles from being overstretched by
their unaffected antagonists. Deformities which result from
the permanent paralysis of some muscle or muscles may be
diminished by operative treatment.

Arthrodesis is restricted to cases of widespread paralysis
with flail joints.

When the paralysis is more limited; nerve-anastomosis, a
practice as yet in process of development; or tendon trans-
plantation, may be carried out. In the latter operation; either
the whole or part of the tendon of an unaffected muscle may be
transplanted into the tendon of one of the paralysed muscles,
or it may be inserted subperiosteally to a fresh attachment so
as to restore the muscular balance of the foot.

The following table shows the position in which tenotomy
of the various tendons can be carried out most conveniently :

Tendon.

Position of Incision.

Tibialis Anterior.
Tibialis Posterior.
Tendo Calcaneus.

Peronsei (Longus and

Brevis).
Extensor Hallucis Longus.

Extensor Digitorum Longus
and Peronaeus Tertius.

At lateral side of tendon, just anterior to

the tuberosity of the navicular.
At medial side of tendon, proximal to the

medial malleolus.
i£ inches (in the child, £ inch) proximal to

its insertion.
At lateral side of tendons proximal to tip

of lateral malleolus.
At lateral side of tendon (to avoid injuring

the dorsalis pedis), and opposite the

tuberosity of the navicular.
At medial side of tendons (to avoid injuring

the anterior tibial vessels), either at the

ankle-joint or one inch proximal to it.

THE REGION OF THE ANKLE AND FOOT 497

In each case, after the incision has been made, a blunt-pointed
tenotome is introduced between the tendon and the bone on
which it lies. The tendon is then stretched across the edge of
the knife and divided.

The plantar aponeurosis may be divided through a number
of small incisions, made in the neighbourhood of the tightened
bands.

Ossification of the Metatarsal Bones and Phalanges. —
Each of the metatarsals and each of the phalanges possesses a
single epiphysis. In the cases of the second, third, fourth, and
fifth metatarsals, the epiphysis forms the rounded head of the
bone. It appears during the third or fourth years and unites
with the diaphysis at eighteen. In the case of the first
metatarsal, the epiphysis forms the base of the bone. It
appears during the second or third years and joins the diaphysis
at eighteen.

The ossification of the phalanges is similar to that of the first
metatarsal. The epiphyses, which appear at the fourth year
and fuse at eighteen, form the proximal extremities.

It may be noted that the first metatarsal resembles the
phalanges still further in the frequency with which it is attacked
by tuberculous disease.

Tuberculous disease of the metatarsals commences near the
centre of the diaphysis as an osteo-myelitis, probably owing to
the fact that the nutrient artery, on entering the bone, at once
divides into a leash of small vessels and not into large ascending
and descending branches, as it does in the long bones proper.

The first metatarsal may be resected subperiosteally through
a dorso-medial incision, which at once exposes the bone. After
the periosteum has been freely elevated, the diaphysis is divided
near the head and can be wrenched away from the epiphyseal
cartilage, which is left behind with the basal epiphysis. In this
way the surgeon avoids opening into the tarso-metatarsal and
the metatarso-phalangeal joints.

The same method may be followed in resection of any of the
other metatarsals, save that the diaphysis must be divided near
the base and then wrenched away from the distal epiphysis

(P- 93)-

In sub-periosteal resection of the proximal phalanges of the

lateral four toes, a dorso-lateral incision is employed to avoid
injuring the tendons of the lumbricals, which are inserted into
the tibial sides of the phalangeal bases.

32

498 THE INFERIOR EXTREMITY

In Hallux Valgus the great toe becomes excessively
adducted and overrides or underlies the second toe. The
condition is caused by the wearing of faultily made boots or
shoes, which in addition to being too short, have the point of
the toe in line with the third instead of in line with the first
digit. The toes, therefore, are approximated to one another
in the narrow toe of the boot. Once the normal alignment of
the great toe is altered, the distortion is increased by the action
of the long flexor and extensor tendons. In pronounced cases,
these tendons and the lateral metatarso-phalangeal ligament
become shortened and the medial part of the head of the first
metatarsal is rendered unduly prominent. A bursa, which
subsequently develops into a bunion, is formed over the bone.

The condition may be improved by the resection of the
distal two-thirds of the head of the first metatarsal. A semi-
lunar incision, the base of which is directed towards the sole,
is made over the prominence, and the skin and fascia are elevated
together and retracted downwards. The adventitious bursa
is dissected free except at its proximal part, so that it can be
turned inwards between the first phalanx and the cut surface
of the metatarsal. It is stitched in this position, after the head
has been excised.

Hallux valgus may be associated with a deformity of the
second toe, known as " Hammer Toe." The latter condition
may be present alone, affecting the lateral four digits of each
foot, and it is then not infrequently congenital in origin. It
may, however, be acquired, independently of hallux valgus,
by the wearing of boots or shoes which are too short.

The metatarso-phalangeal and the distal interphalangeal
joints are hyper-extended, while the proximal interphalangeal
joint is acutely flexed. The prominent head of the first phalanx
may be excised through a dorso-lateral incision. The skin and
the dorsal extensor expansion, which forms the dorsal ligament
of the joint (cf. p. 93), are divided and retracted to the medial
side. The proximal interphalangeal joint is thus widely opened,
and after the lateral ligament has been divided and the second
phalanx still further flexed, the head of the first phalanx may
be dislocated into the wound.

Hallux Rigidus, which is not uncommonly associated with
flat foot, is due to collapse of the longitudinal arch of the foot.
Under normal conditions the long axis of the first metatarsal is
directed forwards and downwards, whereas the long axis of the

THE NERVES OF THE LOWER LIMB 499

phalanges is parallel to the ground. In hallux rigidus the base
of the metatarsal sinks downwards so that its long axis is brought
into line with the axis of the phalanges. At the same time the
head of the bone becomes rotated upwards and the dorsal portion
of its articular cartilage ceases to be articular. This exposed
area undergoes fibrous change, and attempts at dorsi-flexion
cause severe pain. Reflex spasm of the muscles occurs and the
toe is kept rigid.

THE NERVES OF THE LOWER LIMB.

The Nerves of the Lower Limb are derived from the
lumbar and sacral plexuses (L. 2 — S. 3). Plexus injuries are
very rare, and with the exception of the common peroneal nerve,
the nerves of the lower limb are seldom damaged by violence.

The Femoral Nerve (L. 2, 3, and 4) is sometimes injured
in gun-shot or stab wounds, or it may be involved by a psoas
abscess, but the lesion is rarely complete. The quadriceps
femoris is paralysed, and the leg, therefore, cannot be extended,
but it can be brought forwards in walking " by using the
adductors, after the leg has been everted " (Sherren).

The sensory disturbance is most marked over the distal two-
thirds of the leg and the adjoining part of the foot, on their
medial aspects, i.e. over the distribution of the saphenous nerve.

The Sciatic Nerve (L. 4, 5, S. i, 2, and 3) consists of two
portions, the tibial (L. 4, 5, S. i, 2, and 3) and the peroneal
(L. 4, 5, S. i, 2), which, although enclosed in a common sheath
in the proximal part of the thigh and in the buttock, are
separable up to their origins from the plexus. The sciatic nerve
may be injured by penetrating wounds, dislocations of the hip-
joint, or fractures of the pelvis. The lesion is usually incomplete,
and in 90 per cent of cases (Makins) it is referable to the peroneal
part of the nerve.

When the injury is complete, all the muscles of the leg and
foot are paralysed, and if the nerve is divided in the gluteal
region, the hamstrings are also involved. Flexion of the leg,
however, may be carried out by the gracilis (obturator n.) and
the sartorius (femoral n.).

Sensory disturbances are limited to the foot and the lateral
aspect of the leg.

32 a

500

THE INFERIOR EXTREMITY

The Common Peroneal Nerve (L. 4, 5, S. i and 2) may be
injured in fractures of the neck of the fibula, in scythe wounds
and during forcible movements of the ankylosed knee-joint.

The muscles of the anterior and lateral compartments of the
leg are paralysed and the foot, therefore, adopts the attitude
of talipes equino-varus (p. 495).

L!V

, Lumbo-sacral trunk

Superior gluteal nerve

Inferior gluteal nerve

To piriformis I

To piriformi

Nerve to quadratus femoris
Nerve to obturator internus

Sciatic nerv

Common
peroneal nerve

Sciatic nerve

\ Tibial nerve

Post. cut. N. of thigh (O.T. small sciatic)
Perineal N. and dorsal N. of penis | Pudend:
Inferior haemorrhoidal nerve / nerve

'-Perforating cutaneous nerve

Nerves to levator ani
Coccygeal branches

FIG. 148. — Diagram of the Sacral Plexus.

When the nerve is injured, proximal to the point of origin of
its lateral cutaneous branch (p. 446), alterations in sensibility
are found over the dorsum of the foot and the lateral and anterior
aspects of the leg, but, when the injury occurs distal to that point,
the sensory disturbance is confined to the dorsum of the foot.

The Tibial Nerve (L. 4 and 5, S. i, 2, and 3) is rarely injured,
but when it is completely divided, all the muscles of the sole of
the foot and of the posterior compartment of the leg are paralysed.

THE NERVES OF THE LOWER LIMB

501

The foot, therefore,, assumes the attitude of talipes calcaneo-
valgus. Loss of sensibility occurs in the skin of the sole of the
foot.

The Obturator Nerve (L. 2, 3, and 4) may be injured in
anterior dislocations of the hip-joint, in obturator hernise, or
during parturition. The injury, however, is very uncommon.

With the exception of the portion of the adductor magnus
supplied by the sciatic nerve (p. 410), all the adductor muscles
are paralysed, but no sensory disturbance is caused, as the
obturator nerve possesses no exclusive area of sensory supply.

The Lateral Cutaneous Nerve of the Thigh (L. 2
and 3) possesses an area of exclusive supply over the proximal
third of the lateral aspect of the thigh. When the nerve is
divided, epicritic and protopathic sensibilities (p. 97) are lost
over this area.

The following table shows Kocher's views with regard to
the segmental innervation of the muscles of the lower limb
(cf. p. 105).

Nerve.

Muscles.

L. 2.

L.3-

L.4.
L. 5-

S. i.

S. 2.

Cremaster.
Psoas major, iliacus, pectineus, sartorius, and the ad-
ductors, brevis, longus and magnus.
Quadriceps femoris, gracilis, and (?) obturator externus.
Glutaeus medius and minimus ; semimembranosus, semi-
tendinosus and biceps.
Glutaeus maximus ; piriformis, obturator internus and
gemelli, quadratus femoris; muscles of anterior and
lateral compartments of leg.
Muscles of posterior compartment of leg; muscles of
sole of foot.

32 &

502 THE THORAX AND VERTEBRAL COLUMN

THE THORAX AND VERTEBRAL COLUMN.

THE THORACIC WALL.

Surface Landmarks. — The upper border of the manubrium
sterni, which is on the same horizontal level as the fibre-cartilage
between the second and third thoracic vertebrae, can be felt
in the jugular (supra-sternal) notch.

The junction between the manubrium and the body of the
sternum is marked by a transverse ridge, which is known as the
sternal angle (of Louis). The second costal cartilage articulates
with the sternum at the lateral extremity of the sternal angle
and can always be identified with certainty. As the first costal
cartilage is obscured by the clavicle, the sternal angle is a
valuable landmark when it is necessary to identify the individual
ribs.

The anterior halves of the second and third ribs are almost
horizontal, and the corresponding interspaces are widest near
the sternum. The lower costal cartilages ascend with increasing
degrees of obliquity, and the corresponding interspaces are
greatest at the junction of the ribs with their cartilages.

The muscular landmarks produced by the pectoralis major
(p. 2) and the muscles of the back (p. 239) have already been
described.

The apex-beat of the heart is felt in the fifth intercostal space,
3^ inches from the median plane. It is not always visible,
but it can always be felt, especially if it is accelerated and
strengthened by slight physical exercise.

Fracture of the Ribs may result either from direct or
from indirect violence. In the former case, the broken ends are
forced inwards. They may penetrate the pleura and wound
the lung, or they may pierce the diaphragm and injure the liver
or the spleen. Hsemo-thorax, pneumo-thorax, or surgical
emphysema may result.

When the injury is due to indirect violence, the thorax being
compressed antero-posteriorly, the rib commonly breaks just
in front of its angle, and the fragments, which subsequently
tend to overlap, are in the first place forced outwards. On

THE THORACIC WALL 503

this account, there is little danger of injury to the deeper
structures.

The Intercostal Spaces are occupied by the internal and
external intercostal muscles, with their vessels and nerves. The
fibres of the external intercostals pass downwards and medially
from the lower border of the costal groove of the rib above to
the upper border of the rib below. The fibres of the internal
intercostals pass downwards and laterally from the upper
border of the costal groove of the rib above to the upper border
of the rib below.

The costal groove is placed on the lower part of the inner
surface of the rib and is best marked posteriorly. It lodges
an intercostal vein, artery, and nerve, which lie in that order
from above downwards so that the nerve is more exposed than
the vessels. On this account, when a needle is passed into
the chest, the instrument is kept close to the upper border of
a rib.

Medial to the costo - chondral junctions the external
intercostal muscle becomes a fibro - tendinous sheet, which
is termed the anterior intercostal membrane. The internal
intercostal muscle, although extending to the lateral margin
of the sternum in front, is deficient at the vertebral end of the
intercostal space, where it is replaced by the posterior intercostal
membrane.

The lateral extremities of the costal cartilages become
enlarged in rickets and form small elevations, which constitute
the condition known as the " rickety rosary."

The Internal Mammary Artery descends at a distance of
half an inch from the side of the sternum. Posteriorly, it rests
on the costal pleura and, in the lower part of its course, on
the slips of the transversus thoracis (triangularis sterni), which
pass obliquely from the posterior aspect of the sternum to the
upper costal cartilages. Anteriorly, the artery is in relation
to the costal cartilages and the internal intercostal muscles,
and is crossed by the intercostal nerves. At the sixth inter-
costal space the internal mammary artery ends by dividing
into the superior epigastric (p. 253), which descends in the
sheath of the rectus abdominis, and the musculo-phrenic, which
runs downwards and laterally along the costal origin of the
diaphragm.

Ligature of the internal mammary vessels for stab-wounds
should be carried out through a transverse incision over the

32 c

504 THE THORAX AND VERTEBRAL COLUMN

sternal end of the second intercostal space. The pectoralis
major is split, and the' anterior intercostal membrane and the
internal intercostal muscle are divided in the line of the incision.
The vessels are then exposed, half an inch from the sternum,,
lying on the parietal pleura.

A few lymph glands are associated with the internal mammary
vessels at the medial ends of the second and third intercostal
spaces (p. 26).

In the operation of Paracentesis Thoracis an exploring
needle is introduced into the pleural sac through one of the
intercostal spaces overlying the dull area. In order to avoid
injuring the intercostal vessels and nerve, the needle is inserted
close to the upper border of the rib which forms the lower
boundary of the space selected. When the puncture is made
through the lower part of the thoracic wall, the needle should
be directed upwards and inwards as soon as it enters the pleural
sac, lest the diaphragm be penetrated. During the operation
the skin over the selected space is drawn upwards so that, when
the needle is withdrawn, the track of the puncture is practically
obliterated.

In Empyasma an incision is made along the eighth or ninth
rib, with its centre in the posterior axillary line. During the
operation, the patient lies on the sound side with the arm of the
other side flexed and adducted. In this position the inferior
angle of the scapula is drawn forwards and upwards, and the
seventh rib is exposed. Care must be taken to make certain
that the incision is not made over the seventh rib, as the wound
would be subsequently obstructed by the scapula when the arm
resumed its normal position.

The skin and fasciae and the lower border of the latissimus
dorsi, which is exposed in the posterior part of the incision, are
all divided, and the wound is deepened through the serratus
anterior. The rib is then exposed and an incision is made
through the periosteum in its long axis. A transverse cut is
made at each extremity of this incision, and the periosteum is
then stripped off both surfaces of the rib. A portion of the rib
can be resected without injuring the intercostal vessels and
nerves. The wound is then deepened through the inner layer
of the periosteum and the costal pleura. The pus must not
be allowed to escape too rapidly as the sudden diminution of
pressure may lead to heart-failure. A large tube is fixed in
position and the edges of the wound are drawn together.

THE THORACIC CONTENTS 505

When it is necessary to resect one of the lower ribs, the
position of the lower limit of the pleural sac (p. 509) and the
fact that the costo-diaphragmatic recess may be obliterated by
adhesions must be remembered. Otherwise the diaphragm
may be divided and the peritoneal cavity opened.

The same method of approach may be employed when a rib
is the site of tuberculous disease. As much of the infected bone
and of the periosteum on the outer surface is removed as may
be necessary, but the periosteum on the internal surface, after
being carefully scraped, is left otherwise intact and the skin
wound is then closed.

When the lung has been collapsed for some time in the
presence of a chronic empyaema, extensive resection of ribs
(Estlander, Schede, and Kocher) may be performed to allow
the chest wall to fall in and obliterate the persistent cavity.

A large semilunar incision is made over the lateral aspect of
the chest so that its lowest part corresponds to the bottom of
the cavity. The anterior extremity of the incision may extend
upwards to the lower border of the pectoralis major, and its
posterior extremity may ascend between the vertebral border
of the scapula and the vertebral spines. In the latter case, the
latissimus dorsi, the trapezius, and the rhomboids are all divided.
The U-shaped flap thus marked out consists of all the soft parts
down to the ribs. When it is retracted upwards, portions of
the second to the eighth or ninth ribs may be resected from
their angles to their costal cartilages. The periosteum and the
thickened parietal pleura are also removed so that the chest
wall may be able to fall in upon the collapsed lung.

In certain cases the lung may be decorticated of its thickened
visceral pleura in the hope that it may be able to re-expand.

THE THORACIC CONTENTS.

The Pleurae. — Each lung is enclosed in a serous membrane,
termed the pleural sac. The pleural membrane consists of a
visceral layer, which is closely adherent to the lung and lines
the fissures in its substance, and a parietal layer. The two
pleural sacs are separated from one another by the mediastinal
space, which contains the heart, the great vessels, the trachea,
the oesophagus, etc., and those parts of the pleural membrane

506 THE THORAX AND VERTEBRAL COLUMN

which form the lateral boundaries of the mediastinum are
termed the mediastinal pleura.

When the arrangement of the pleura is examined in a
transverse section of the thorax at the level of the fourth thoracic
vertebra, it is seen that the costal pleura lines the inner
surfaces of the ribs and, anteriorly, it passes medially behind
the sternum to the median plane. The membrane is then
reflected backwards over the great vessels till it reaches the
vertebral column.

If the section is made at a slightly lower level (Fig. 149), it

Costal part of parietal pleur

Pleural cavity Nv
Visceral pleura

Costal part of parietal pleura
Pleural cavity
Visceral pleura

FIG. 149. — Diagram of a Transverse Section through the Thorax,
at the Level of the Root of the Lung.

passes through the root of the lung. On passing backwards
from the sternum, the mediastinal pleura clothes the pericardium
and reaches the anterior aspect of the root of the lung, on which
it is carried laterally to become continuous with the visceral
pleura. After covering the lung, the pleura is carried medially
on the posterior aspect of the root and again reaches the
pericardium, on which it passes backwards to the vertebral
column.

When a frontal section is examined, it is found that, when
the costal pleura is traced downwards, it extends for some
distance below the lower border of the lung and is then reflected
on to the diaphragm. In this inferior extremity of the pleural

THE THORACIC CONTENTS

507

sac, which is termed the phrenico-costal sinus, the costal and
diaphragmatic pleurae are in immediate contact with one another
for a considerable distance during ordinary quiet inspiration.

The costal pleura becomes continuous with the mediastinal
pleura not at one point only, as in Fig. 149, but along

\

FIG. 150. — Surface Relations of the Liver, Stomach, Lungs, Heart

and Pleural Sacs.

Blue line — outline of lung. Dotted blue line = lines of pleural reflection.
Fine black line = heart and great vessels. Heavy black line = liver. Dotted
black line = stomach.

a line termed the costo-mediastinal line of pleural reflection,
and similarly the costal pleura becomes continuous with the
diaphragmatic pleura along a line which is termed the costo-
diaphragmatic line of pleural reflection. These lines indicate the
limits of the pleural sacs and their relation to the surface of the
body is of great importance.

Superiorly, the pleura bulges upwards for about one inch

5o8 THE THORAX AND VERTEBRAL COLUMN

above the sternal end of the clavicle into the root of the neck.
In this area the apex of the lung is in close contact with the
parietal pleura, which separates it from the subclavian artery

(p. 142).

Surface Relations
of the Lungs and
Pleural Sacs. — The
Cervical Pleura can be
indicated on the surface
by a curved line, with an
upward convexity, drawn
from the centre of the
sterno-clavicular joint to
the junction of the sternal
and middle thirds of the
clavicle. The summit of
the convexity should not
be more than one inch
above the clavicle (Fig.

The Costo-Medias-
tinal Line of Pleural
Eeflection is not the
same on both sides of
the body. On the right
side it commences above
at the sterno-clavicular
joint and passes down-
wards and medially to
the centre of the manu-
brium sterni. From that
point it descends vertic-
ally, in or near the
median plane, to the
level of the sixth costal
cartilage, where it becomes continuous with the costo-diaphrag-
matic line of reflection. On the left side, the line of reflection is
similar until the level of the fourth costal cartilage is reached.
At that point it deviates laterally to the left border of the
sternum down which it descends to the sixth chondro-sternal
articulation, where it becomes continuous with the costo-
diaphragmatic line of reflection.

FIG. 151. — Surface Relations of Right Lung,
Pleural Sac and Liver, from the Lateral
Aspect.

Blue line = the lung and its fissures.

Dotted blue line = pleural sac.

Heavy black line = liver.

THE THORACIC CONTENTS 509

In the interval which is left between the two pleural sacs
behind the lower part of the left half of the sternum, the
pericardium comes into direct contact with the anterior thoracic
wall (p. 510).

The Costo - Diaphragmatic Line of Pleural Reflection
indicates the lowest limit of the pleural sac. Although some-
times a little lower on the left side, it may, for practical purposes,
be mapped out on the surface on the two sides of the body by
similar lines. It begins at the lower end of the costo-mediastinal
line and passes laterally and downwards behind the seventh
costal cartilage and the seventh intercostal space. In the
lateral line (mid-clavicular or mammary), the costo-diaphragmatic
line crosses the eighth rib, at its junction with its cartilage. It
continues to descend slightly as it passes round the body, and
in the mid-axillary line it cuts the tenth rib. On the posterior
aspect of the trunk the line of reflection ascends slightly as it
passes towards the vertebral column, and crosses the eleventh
and twelfth ribs, the latter at the point where it is crossed by the
lateral border of the sacro-spinalis (see also p. 275). It reaches
the vertebral column at the level of the twelfth thoracic spine,
i.e. nearly half an inch below the head of the twelfth rib
(Fig. 84).

The Lower Border of the Lung lies at a much higher level
than the costo-diaphragmatic line during quiet respiration.
In the lateral (mammary) line the lower border of the lung crosses
the seventh rib and lies about i£ inches above the lower limit
of the pleura. In the mid-axillary line the difference is most
marked and a distance of three or four inches separates the
lower border of the lung, which is placed on the eighth rib, from
the lower limit of the pleural sac. Posteriorly the difference
is not so great, but the phrenico-costal sinus extends usually
two inches below the lower border of the lung, which corresponds
to the tenth thoracic spine (Fig. 84). On the right side of the
body the phrenico-costal sinus is related to the liver and,
posteriorly, to the upper pole of the right kidney (p. 275). On
the left side it comes into relation successively with the left
lobe of the liver, the stomach, the spleen (p. 320), and the upper
pole of the left kidney.

The Anterior Border of the Right Lung is straight and
coincides with the costo-diaphragmatic line of pleural reflection.
The Anterior Border of the Left Lung possesses a deep notch
at its lower end, which falls short of the lateral margin of the

510 THE THORAX AND VERTEBRAL COLUMN

sternum by at least one inch. At the sternal ends of the
fourth and fifth spaces and behind the sternal ends of the
fifth and sixth cartilages of the left side, the pericardium is
only separated from the chest wall by a double layer of pleura.
Light percussion of this area, therefore, produces a dull note,
and the area will be increased in size when the anterior border
of the left lung is retracted owing to pressure or disease (see
below).

The Heart and Pericardium. — The Pericardium is a
fibro-serous sac which encloses the heart and the roots of the
great vessels. Under normal conditions its outline corresponds
to the outline of the heart, but, when greatly distended, it
becomes pear-shaped with the blunted apex superiorly.

The Right Border of the Heart is entirely formed by the
right atrium (auricle). It begins above at the third right costal
cartilage half an inch lateral to the sternum, and descends, with
a slight convexity to the right, to the sixth costal cartilage.
Its maximum distance from the median plane is in the fourth
interspace and amounts to i| inches.

The Lower Border of the Heart extends from the lower
end of the right border to the apex-beat (p. 502). It is formed
mainly by the right ventricle, but the left ventricle forms its
left extremity.

The Left Border of the Heart extends upwards and
medially from the apex to the second left intercostal space,
where it lies at a distance of half an inch from the sternum.
It is gently convex upwards and to the left, and corresponds to
the rounded border of the left ventricle.

When the heart, pleurae, and lungs are marked in on the
same chest (Fig. 150), it will be found that an irregularly
triangular area of the anterior surface of the heart is uncovered
by the left lung. This area is termed the area of superficial
cardiac dulness, and where it extends beyond the sternum it is
covered by pleura.

Effusion of fluid into the pericardial sac may greatly
increase the size of the area of superficial cardiac dulness, and
the lungs and pleural reflections are displaced laterally.
Curschmann holds that it is not safe to perform paracentesis
pericardii at the lateral border of the sternum, as the fluid tends
to collect posteriorly and laterally, so that the heart is thrust
forwards against the chest-wall. He recommends that the
needle should be inserted in or lateral to the lateral line, and

THE THORACIC CONTENTS 511

passed, in a medial and backward direction,, through the anterior
part of the left pleural sac.

When the effusion is purulent, exposure and drainage of the
pericardium is rendered necessary. A curved flap is turned
upwards and to the left, exposing the left half of the lower part
of the sternum and the costal cartilages of the fifth and sixth
ribs. The sixth costal cartilage is carefully removed piecemeal
and the internal mammary vessels (p. 503) are exposed lying
on the trans versus thoracis (triangularis sterni). When they
have been ligated, the transversus thoracis is divided and the
pericardium is exposed with a thin covering of mediastinal fat.
If necessary, the fifth costal cartilage and the intercostals may
be removed. The fat is wiped away, and the left pleural
reflection is identified and displaced laterally with the ringers.
The pericardium can then be opened and drained.

In suture of the heart for stab-wounds good access is essential
and is obtained by a modification of the approach described
above. The incision is larger and an extensive flap of the
chest-wall may be turned up, by dividing the third, fourth, fifth,
and sixth ribs after their costal cartilages have been cut through
near the sternum.

The (Esophagus begins opposite the sixth cervical vertebra
and descends through the neck, lying behind the trachea and
in front of the vertebral column (p. 139). In the upper part
of the thorax it projects slightly beyond the left side of the
trachea and, opposite the fifth thoracic vertebra, it is crossed
anteriorly by the left bronchus. Below that point, the
oesophagus lies behind the pericardium and in front of the
vertebral column, but it curves forwards away from the latter
as it leaves the thorax. The oesophagus passes through the
diaphragm opposite the tenth thoracic vertebra, and its
abdominal part, which is only half an inch in length, ends at
the cardiac orifice of the stomach.

The oesophagus is slightly constricted at its commencement,
which lies six inches from the incisor teeth, and again at the
point where it is crossed by the left bronchus, which lies four inches
lower down. It possesses a third constriction as it passes through
the opening in the diaphragm, which is sixteen inches distant
from the incisor teeth. (Esophageal bougies should be graduated
from the distal extremity so that the surgeon may locate the
position of an cesophageal obstruction. In healthy subjects
some obstruction may be encountered at the lower end of the

512 THE THORAX AND VERTEBRAL COLUMN

pharynx, and it is caused by the bougie impinging against the
upper border of the posterior part of the cricoid cartilage. If
the patient swallows, the instrument readily slips past the
obstruction. At a distance of rather more than sixteen inches
from the incisor teeth, the bougie enters the cardiac orifice of
the stomach.

Opposite the fourth thoracic vertebra, the oesophagus is
crossed anteriorly by the aortic arch and, in cases of cesophageal
obstruction, the possibility that the condition may be caused

Mediastinal pleura ...

- ~^^' Mediastmal pleura

"8a^|P;>—
Aortic arch

Left bronchus ,

^ ^ '/,' Vena azygos

Left recurrent nerve |

Descending thoracic aorta i^^^^^^j§Thoracic duct

Fourth thoracic vertebra

FIG. 152. — Transverse Section through the Thorax at the Level of the
Fourth Thoracic Vertebra.

by aneurismal pressure must be excluded before a bougie is
passed.

Malignant disease of the oesophagus commonly occurs at
the three places where the tube is normally constricted, and,
when it is situated in the upper thoracic region, the growth may
compress the left recurrent nerve, which ascends in the groove
between the left side of the trachea and the oesophagus (Fig. 152).
In this situation, too, it may perforate the left bronchus and give
rise to septic pneumonia.

When the lower end of the thoracic part of the oesophagus
is the site of new growth, the disease may invade the right
pleural sac and cause an empysema.

THE POSTERIOR THORACIC WALL

THE POSTERIOR THORACIC WALL.

Costo-Vertebral Joints. — The vertebral end of each typical
rib (second-ninth) articulates with the vertebral column by
two separate joints. The head of the rib articulates with the
upper part of the body of the vertebra to which it corresponds
numerically, with the lower part of the vertebra above, and

Body of vertebra

Posterior costo-transverse ligament

FIG. 153. — Transverse Section through a Typical Costo-Vertebral
Articulation.

Light blue = articular cartilage.
Striped blue — ligaments.

Green = periosteum.

Red = synovial membrane.

with the fibro-cartilage between them. The tubercle of the rib
articulates with the transverse process of the vertebra to which
it corresponds numerically, and this joint is strengthened by a
strong ligament (the ligamentum colli costce — inter costo-transverse)
which connects the posterior aspect of the neck of the rib to the
anterior aspect of the transverse process (Fig. 153).

Surgical Approach to the Posterior Mediastinum.—
Tuberculous disease or abscess affecting the thoracic vertebrae

33

514 THE THORAX AND VERTEBRAL COLUMN

may be attacked by the operation of Costo-Transversectomy,
in cases where conservative treatment has failed and where
paralytic signs have not improved with rest, or when radiograms
suggest the presence of sequestra. As the result of the disease,
a certain degree of angular curvature is present, and the incision
begins near the most prominent spine. It is carried laterally
along the rib below, which is to be resected, and all the soft
structures are divided until the rib and the transverse process
with which it articulates are exposed. The periosteum is
elevated and the rib is divided lateral to its tubercle. The
transverse process is divided at its medial end and can be
disarticulated, after the ligamentum colli costae and its other
connections have been divided. The neck of the rib can then

Right bronchus

Left bronchus
I

Oesophagus

'--- Thoracic duct
Descending thoracic a°rta*^K-^^l- Vena azygos

Pleura

Fifth thoracic vertebra

FIG. 154.— Diagram of a Transverse Section through the Upper Part
of the Posterior Mediastinum.

be cut through close to the head. In the last-named step care
must be taken to leave the head of the rib intact, lest the
sympathetic trunk, which descends on the heads of the ribs, be
injured. The periosteum on the inner surface of the rib is next
divided and the pleura, which is now exposed, is retracted.
A finger can then be passed medially towards the vertebral
bodies, and it should be remembered that the disease is most
advanced in the vertebra above the one to which the resected
rib corresponds numerically.

On the right side of the vertebral column the finger meets
with no obstruction, but below the level of the third thoracic
vertebra on the left side the descending thoracic aorta is
encountered (Fig. 154).

Exposure of the (Esophagus. — In the removal of a foreign
body from the oesophagus or a bronchus, or in excision of a

THE POSTERIOR THORACIC WALL 515

carcinoma of the oesophagus, the mediastinum must be exposed
more widely. Access is obtained by reflecting a large musculo-
cutaneous flap, about four inches wide, which has its base over
the vertebral spines. When the upper part of the oesophagus
is attacked, the flap extends from the first to the seventh
intercostal space. The medial portions of four ribs are resected
subperiosteally, and after the intercostal vessels have been
ligated the periosteum and intercostal muscles are carefully
incised at the medial part of the wound.

Owing to the position of the descending thoracic aorta
(Fig. 154) this operation is usually performed on the right side,
and it must be remembered that the right pleural sac forms a
small recess behind the right border of the oesophagus (Fig. 154).

Innominate artery

Left innominate vein T> • u •

"/xgjjSti /^j^^ /^fiO Kignt innominate vein

& ' 99 m

Left common carotid a.

Left subclavian a. I®) ((j^^^k^T Trachea

Left recurrent nen^-^ B^ Mediastinal pleura

Thoracic duct -\jg|||||^ (ESOphagus
Mediastinal pleura —

-- Body of vertebra

FIG. 155. — Transverse Section through the Superior Mediastinum.

The pleura is stripped off the heads of the ribs, the side of the
vertebral column, and the oesophagus, and, if this is done
carefully, there is little danger of injuring the sympathetic
trunk, which descends on the heads of the ribs. The oesophagus,
which can, if necessary, be identified by passing an cesophageal
bougie, can now be freed and brought to the surface, a distance
of about four inches.

When the oesophagus is exposed on the right side below the
root of the lung, care must be taken not to injure the vagus nerve,
which descends along its lateral border. In this situation the
vena azygos and the thoracic duct, which lie behind the oesophagus,
are not likely to be injured, as they tend to remain in contact
with the vertebral column when the pleura is stripped away
and the oesophagus is brought to the surface. At the upper
border of the root of the right . lung the vena azygos turns

516 THE THORAX AND VERTEBRAL COLUMN

forwards, crossing the lateral aspect of the oesophagus to enter
the superior vena cava, and, if necessary, it may be ligatured
in this part of its course.

In the upper part of the thorax the oesophagus lies slightly
to the left of the median plane, and, as it is situated above the
arch of the aorta, it may be approached from the left side. When
the pleura is stripped off the vertebral column and retracted,
the sympathetic remains intact on the heads of the ribs, but the
thoracic duct and the left recurrent nerve are exposed to injury.
In this part of its course the thoracic duct is closely applied to
the left border of the oesophagus, and it should be identified and
separated before the oesophagus is freed. As the vagus crosses
the arch of the aorta it gives off the left recurrent nerve, which
ascends behind the vessel, to the left of the trachea and in front
of the left edge of the oesophagus (Fig. 155). The left subclavian
artery passes upwards, backwards, and to the left from the
aortic arch, and opposite the second thoracic vertebra it is in
close contact with the lateral border of the oesophagus, from
which it is separated by the thoracic duct. The position of this
large vessel must be kept in mind while the oesophagus is being
freed.

THE VERTEBRAL COLUMN AND THE
SPINAL MEDULLA.

Ossification of the Vertebrae. — Each typical vertebra
possesses three primary centres of ossification — one for the
body, and one for each half of the verte-
bral arch. The two halves of the
vertebral arch unite with each other
posteriorly, and this process, which begins
in the cervical region at the end of the
first year, extends very gradually to the
other regions, so that it is not completed
in the sacrum till between the seventh

„ . and tenth years. The vertebral body is
FIG. 156. — Ossification of , ' .

a Vertebra. separated from the vertebral arch on

each side by a bar of cartilage, which is

termed the neuro-central synchondrosis, and it disappears about
the third or fourth year.

Centre for
body

THE VERTEBRAL COLUMN 517

In some cases the neuro-central synchondrosis may persist,
especially in the lumbar region. In the interpretation of

FIG. 157. — Kyphosis, produced by Tuberculous Disease of Thoracic
Vertebras. (From a specimen with ribs removed. )

radiograms of the vertebral column, care must be taken not
to mistake this anomaly for a fracture.

Five secondary centres appear at puberty, and the epiphyses
so formed unite with the rest of the bone at twenty-five. They
are placed at the extremities of the spine and the transverse

5i8 THE THORAX AND VERTEBRAL COLUMN

processes and on the superior and inferior aspects of the body.
The two latter form ring-like epiphyses and do not extend over
the whole of the surfaces on which they are situated.

The tendency for tuberculous disease to attack growing
bone is well illustrated by the frequency of Pott's disease in

FJG. 158. — Pott's Disease in Thoracic Region of a Child. The abscess
is undergoing calcification and absorption.

childhood compared with its comparative rarity after puberty.
The infection being carried by the blood-stream; the disease
begins as an osteo-myelitis near the anterior surface of the body,
because the nutrient artery enters the body posteriorly and
breaks up into a leash of small vessels about its centre. Owing
to the absence of complete epiphyseal plates, it readily spreads
to the adjoining vertebrae.

If the disease spreads forwards, the anterior part of the

THE VERTEBRAL COLUMN 519

vertebral body is destroyed and collapses, but the posterior
part does not give way to the same extent owing to locking of
the healthy articular processes. As a result, the part of the
vertebral column above the disease is bent forwards on the
part below, giving rise to angular curvature (Fig. 157).

When the disease spreads backwards, the pus may erupt
through the periosteum and the posterior longitudinal ligament
into the vertebral canal, where it lies outside the dura mater
and may compress the spinal medulla. If the disease occurs
before the age of five, it is prevented by the neuro-central
synchondroses from spreading postero-laterally into the vertebral
arch (Fig. 156).

The periosteal type of the disease affects the anterior surfaces
of the bodies of several adjoining vertebrae and results in a
gradual collapse, which tends to produce a gentle curvature of
the vertebral column rather than a sharp angular curvature.

Joints at the Upper End of the Vertebral Column.—
The Atlas, or first cervical vertebra, has no body, and it consists
of a short anterior arch and a longer posterior arch, connected
to one another on each side by the lateral mass. The superior
surfaces of the lateral masses articulate with the condyles of the
occipital bone, and at this joint only nodding movements of the
head are possible.

The inferior surfaces of the lateral masses articulate with
the superior articular facets of the second cervical vertebra.
The Dens (Odontoid Process), which represents the body of
the atlas, projects upwards from the body of the second cervical
vertebra. Its anterior surface articulates with the posterior
surface of the anterior arch of the atlas, and it is held in position
by the transverse ligament, which connects the two lateral masses
and is separated from the posterior surface of the dens by a
small bursa (Fig. 50).

In rotatory movements of the head, the atlas, which carries
the skull with it, moves on the second cervical vertebra.

Tuberculous disease not uncommonly originates in the
body of the second cervical vertebra or in the dens. From the
latter situation it may spread forwards and infect the articulation
between the dens and the atlas ; or, it may spread backwards
and infect the bursa between the dens and the transverse
ligament. These joints are supplied by branches from the
first and second cervical nerves, which also supply the muscles
which rotate the head. Irritation of the branches of these

520 THE THORAX AND VERTEBRAL COLUMN

nerves leads to reflex phenomena. Pain is experienced over
the cutaneous distribution of the second cervical nerve (Fig. 72)
— the first cervical nerve has no cutaneous branches — and the
head is kept rigid owing to muscular spasm.

If the transverse ligament is destroyed or the dens eroded,
the head slips forwards and the spinal medulla (spinal cord) is
crushed. Death results as the injury occurs above the level of
the origin of the phrenic nerve (p. 530).

When the body of the third or fourth cervical vertebra is
the site of the disease, the same rigidity from muscular spasm
is present, and pain is experienced over the cutaneous
distribution of the third and fourth cervical nerves. These
symptoms are due to pressure on the nerves themselves as they
pass out from the vertebral canal, unless the joints between
the articular processes are involved, in which case they may be
entirely reflex.

Vertebral Caries. — In abscess formation, the pus may
escape to one or other side of the anterior longitudinal ligament,
which connects the anterior surfaces of the vertebral bodies to
one another, or it may perforate the ligament. It then gives
rise to a retro-pharyngeal abscess, which can readily be recognised
on palpation of the posterior wall of the pharynx with the
finger. The abscess destroys the longus colli and comes to lie
behind the prevertebral fascia. It may extend laterally (p. 113)
into the floor of the posterior triangle (Fig. 36), and its sub-
sequent course is described on p. 114.

The abscess may be approached through an incision along
the posterior border of the sterno-mastoid, which is retracted
forwards along with the carotid sheath (Chiene). The anterior
tubercles on the transverse processes are palpated and the
abscess is opened, slightly to their medial side, by Hilton's
method (cf. evacuation of acute retro-pharyngeal abscess,
p. 114).

When the disease involves the lower cervical and
upper thoracic vertebrae, the affected part of the vertebral
column is held rigid by muscular spasm. Referred pain is
experienced in the upper limbs (Fig. 14) and its distribution
may help to determine the precise site of the disease. In
advanced cases angular curvature may be present. When an
abscess forms, the pus tends to track downwards behind the
anterior longitudinal ligament or the prevertebral fascia into
the mediastinum. Following the course of the dorsal branch

THE VERTEBRAL COLUMN

521

of an intercostal vessel, it may ultimately point through the
muscles of the back.

When the disease originates in the mid-thoracic region,
muscular spasm produces boarding and rigidity of the sacro-
spinales and, sometimes, the abdominal muscles. Pain may be

Posterior column of spinal medulla

Posterior nerve-root
Anterior nerve-root |
Spinal ganglion
or rainus (medial branch) ^^^ff^

Anterior column of spinal medulla

Posterior rai

Posterior ramus (lateral brand

Recurrent meningeal branc

Gray ramus coinmimican* —

Splanchnic branch (white rainus ^

communi

Anterior ram

Lateral branch (poste
subdivis:

Lateral branch

ateral branch (anterior .
subdivision)

^

Oiingliated sympathetic

trunk

Efferent (vaso-motor)

branch

Afferent viscero-
inhibitory branch

FIG. 159. — Scheme of the Distribution of a Typical Spinal Nerve.

experienced in the back, but it is very frequently referred to the
anterior abdominal wall, and it may then lead to errors in
diagnosis. Abscesses may point through the muscles of the
back, or they may follow the course of an intercostal nerve
and come to the surface by tracking along its lateral cutaneous
branch (Fig. 159).

522 THE THORAX AND VERTEBRAL COLUMN

Abscesses in connection with the lower thoracic vertebrae
may enter the posterior mediastinum and gravitate downwards
behind the medial lumbo-costal arch (internal arcuate ligament,
p. 272). They subsequently descend under the fascial covering
of the psoas major (p. 271).

When the disease commences in the lumbar region,
referred pain may be experienced in the back, in the lowest
part of the anterior abdominal wall, in the anterior, medial, or
lateral apects of the thigh, or in the medial aspect of the leg
(Figs. 118 and 124). Deep hyperalgesia may be found in any of
these areas and muscular spasm may also be present.

Abscesses arising in connection with the lumbar vertebrae
may spread laterally and point in the loin (Fig. 83) ; or, they
may descend behind the fascial covering of the psoas major and
follow the femoral nerve into the thigh ; or, they may follow
the glut eal or sciatic nerves and enter the buttock (see also p. 415).

Paraplegia may come on at any stage of tuberculous disease
of the vertebral column, but it occurs most frequently when
the upper thoracic region is involved. It is not as a rule due to
bony pressure, for, although the angular curvature may be so
marked that the spinal medulla is actually compressed, this
condition arises so gradually that it does not lead to paralysis.
Paraplegia is usually caused by a backward spread of the
disease into the vertebral canal. Tuberculous pachymeningitis,
or an abscess, or a sequestrum may compress the spinal medulla
and give rise to paralysis of the lower limbs. The signs of this
condition are outlined on p. 529.

Examination of the Vertebral Column. — In suspected
cases of tuberculous disease, the examination of the vertebral
column must be carried out systematically by means of both
active and passive movements. The active movements of
flexion, extension, rotation, and lateral flexion are first examined
and any limitation is observed. The patient is then placed face
downwards on the table and passive movements are carried out
by acting on the vertebral column through the lower limbs and
pelvis. A positive diagnosis depends, to a large extent, on the
discovery of abnormal rigidity due to muscular spasm. At an
early stage no local pain can be elicited by pressure over the
spines, as the disease originates in the anterior part of the
vertebral bodies. The sensitiveness to deep pressure should
always be tested, as areas of muscular hyperalgesia are frequently
present in the muscles supplied by the segment involved.

THE VERTEBRAL COLUMN 523

Curvatures of the Vertebral Column.— In the foetus
the vertebral column shows two primary curves, both concave
forwards. Of these, one extends from the head to the pelvis
and the other affects the sacral region. When the child begins
to sit up and elevate its head, a forward convexity appears in
the cervical region ; and, when the erect attitude is assumed
and the child begins to walk, a forward convexity appears in
the lumbar region also. The development of these secondary
curves enables the vertebral column to transmit the weight of
the trunk to the pelvis in such a way that little or no muscular
effort is required to maintain the erect attitude.

The amount of movement possible between any two adjoining
vertebrae is very small, but by the summation of these movements
aided by the compressibility of the intervertebral fibre-cartilages,
the vertebral column, as a whole, acquires a moderately extensive
range of movement. In flexion and extension of the vertebral
column the lumbar and cervical regions move more freely than
the thoracic region, but the reverse is the case with regard to
rotation, except in the case of the joints between the atlas and
the second cervical vertebra. Lateral flexion occurs chiefly in
the lumbar region.

In weakly children and debilitated adolescents, the body
may grow more rapidly than the muscles which support it.
These patients instinctively adopt attitudes which relieve the
tired muscles and throw the strain on the ligaments of the
intervertebral joints. The habitual adoption of such attitudes
causes overstretching of the ligaments on which the strain is
thrown, and the opposing ligaments become shortened. There
is, therefore, a tendency for the faulty attitude to be maintained
mechanically. When the proper alignment of the vertebral
column is altered, the muscular balance is upset. One group of
muscles obtains a mechanical advantage over the corresponding
antagonistic group, which consequently becomes overstretched.
As a result, abnormal curves appear in the vertebral column.

Lateral Curvature, or Scoliosis, occurs primarily in the
thoracic region and its convexity is usually directed to the
right side. Compensatory curves, which are convex in the
opposite direction, appear above and below the primary curve,
and they serve to maintain the equilibrium of the body. The
lateral curvature of the thoracic region is not produced by true
lateral flexion of the vertebral column, as this movement is
restricted to the lumbar region. The thoracic vertebrae become

524 THE THORAX AND VERTEBRAL COLUMN

rotated and, at the same time, extended. Owing to the
coincident occurrence of rotation, the movement of extension
produces a lateral curvature instead of a diminution of the
normal forward concavity. The vertebral spines lie in the
concavity of the curve and, as they are close to the median plane,
the apparent amount of lateral curvature, as estimated by
examination of the spines, is much smaller than the actual
amount.

In the later stages, the unequal distribution of pressure
hinders growth in what was originally the posterior part of
the body, and the vertebral bodies become wedge-shaped.

The direction of the ribs is necessarily affected by the
rotation of the thoracic vertebrae. On the convex side of the
curve, the ribs produce a " hump " on the dorsal aspect of the
body and cause elevation of the scapula and shoulder. On the
anterior aspect of the body the ribs are thrust forwards (i.e. on
the concave side of the curve).

The alteration in the shape of the thorax causes a correspond-
ing alteration in the shape and position of the viscera which it
contains.

The condition of scoliosis usually occurs in weak children
and debilitated adolescents, but it may be congenital or it may
follow acute anterior poliomyelitis (cf. p. 494). It can be
distinguished from Pott's disease by the absence of muscular
rigidity.

The backward curvature of Kyphosis, which occurs in
Pott's disease (p. 519), may be caused by constitutional bone
disease or occupational postures. It may also occur in rickets,
owing to weakness of the muscles of the back.

The forward curvature of Lordosis is generally compensatory
to flexion at the hip-joint (p. 435).

The Spinal Medulla (Spinal Cord) begins at the
foramen magnum, where it is continuous with the medulla
oblongata, and terminates at or just below the lower border of
the first lumbar vertebra. In the infant it is relatively longer
and extends to the upper border of the third lumbar vertebra.
The segments of the spinal medulla are therefore more crowded
together than the corresponding vertebrae, and although the
nerve-roots pass horizontally to the intervertebral foramina in
the upper cervical region, their course within the vertebral
canal becomes longer and more oblique in the thoracic region,
while the lumbar and sacral nerve-roots descend almost vertically.

THE SPINAL MEDULLA

525

Floor of fourth ventricle
Vertebral artery

Transverse sinus

Second cervical nerve

Cervical enlargement

J Lower end of spinal
" medulla

FIG. 1 60. —The Spinal Medulla /;/ situ. The dura mater has been partially
removed on the right side and two of the intercostal nerves have been
traced in a lateral direction.

526 THE THORAX AND VERTEBRAL COLUMN

On transverse section (Fig. 161) it is seen that the grey
matter, on each side, is arranged in two columns. The anterior
column is broad and blunted and contains the motor cells which
give origin to the fibres of the anterior nerve-roots. The posterior
column, which is continuous in front with the anterior column,
is somewhat pointed, and near its tip the posterior nerve-roots
enter the spinal medulla.

The anterior nerve-roots, which are purely motor, emerge
from the anterior column of grey matter in series. The posterior
nerve-roots, which are entirely sensory, enter the spinal medulla

FIG. 161. — Diagram of a Transverse Section through the Spinal Medulla.
The anterior (motor) and the posterior (sensory) nerve-roots ; their union
to form a typical spinal nerve and their subsequent division into anterior
and posterior rami are also shown.

in series on its postero-lateral aspect. Each posterior nerve-root
possesses a ganglion, the cells of which give origin to peripheral
and central fibres. In or near the inter vertebral foramina the
anterior and posterior nerve-roots unite to form a spinal nerve
(Fig. 161), and, almost as soon as it is formed, each spinal nerve
breaks up into an anterior and & posterior ramus (primary division).
The rami, both anterior and posterior, are mixed nerves ; their
distribution is dealt with in the various regions of the body.

Membranes. — The spinal medulla is surrounded by three
membranous sheaths, which are continuous with the membranes
of the brain (p. 223). The pia mater is closely applied to the
spinal medulla and, at its lower end, is continued down as a fine

THE SPINAL MEDULLA 527

thread, termed the filum terminate. The subarachnoid space is
continuous with the subarachnoid space in the skull, and it
extends downwards to the second sacral vertebra. Below that
point the arachnoid covers the filum terminale. The dura
mater spinalis consists of a serous layer only, and is not adherent
to the walls of the vertebral canal, to which it is only connected
by the spinal nerves. The subdural space is only continued
downwards to the second or third sacral vertebra, and, below
that level, the dura mater spinalis is closely applied to the filum
terminale, which eventually blends with the periosteum on the
back of the coccyx.

Lumbar Puncture. — The lower part of the sheath formed by
the arachnoid and dura mater contains only the lumbar and
sacral nerve-roots and the filum terminale, which form a leash,
termed the cauda equina. In lumbar puncture, advantage is
taken of the absence of the spinal medulla from the lumbar part
of the vertebral canal to introduce an exploring needle into the
subarachnoid space. The operation may be performed in order
to withdraw some of the cerebro-spinal fluid for examination,
or to inject drugs for the purpose of inducing anaesthesia.

The space between adjoining laminae is greatest in the lower
lumbar region, and on that account either the interval between
the third and fourth or that between the fourth and fifth lumbar
vertebrae is selected. The patient is placed, preferably, in a
sitting posture with the trunk strongly flexed, since the interval
between the laminae is thus slightly increased. The interval
between the fourth and fifth lumbar vertebrae corresponds to the
line joining the highest points on the two iliac crests, and the
site of the puncture lies on this line half an inch from the median
plane. A fine exploring needle, fitted with a stilette, is thrust
forwards and slightly upwards and medially through the skin,
fasciae, and sacro-spinalis. After passing through the muscle
the needle pierces the ligamentum flavum, which connects the
laminae ; the ligament can be readily recognised by the resistance
that it causes. The needle then enters the vertebral canal and,
piercing the dura mater and arachnoid, gains the subarachnoid
space, at a distance of about two inches from the surface. If the
instrument has reached the subarachnoid space, withdrawal of
the stilette will be followed by the escape of cerebro-spinal fluid.
It is apparently immaterial whether the fluid withdrawn is
obtained from the subdural or from the subarachnoid space.

When the operation is performed for the purpose of inducing

528 THE THORAX AND VERTEBRAL COLUMN

spinal anaesthesia,, the level of the anaesthesia may be roughly
regulated by the position of the patient after the injection.
Where it is desired to reach a high level, the patient may be
placed flat upon the back, but with the head and neck flexed lest
the centres in the medulla oblongata become affected.

Injuries of the Vertebral Column and the Spinal

Dens f—

Foramen in transverse ._
process

Joint between articular
processes

Inferior articular pro-

cess of 4th cerv. vert.

Position of emerging

C- 5

Articular process of
5th cerv. vert.

Pointer in interverte-
bral foramen

FIG. 162. — Unilateral Rotatory Dislocation of the Fourth Cervical Vertebra.
The inferior articular process of the fourth cervical vertebra has slipped
forwards over the superior articular process of the fifth. In this position
it usually presses upon the fifth cervical nerve and causes pain which is
referred to the areas supplied by its terminal branches.

Medulla. — The cervical part of the vertebral column most
frequently suffers injury since it normally possesses the greatest
range of movement. Slight injuries of the vertebral column
may produce serious results owing to the delicate structure of
the spinal medulla.

Unilateral, rotatory luxation of an articular process
may occur as the result of a sudden twist or bend, and may be

THE SPINAL MEDULLA 529

partial or complete. In some cases the dislocation may be
reduced spontaneously ; in others, the condition may be mistaken
for a stiff or sprained neck and the correct diagnosis may be made
only after radiographic examination. The inferior articular
process slips forwards over the superior articular process of the
vertebra below, and it may compress the spinal nerve, giving
rise to referred pain over its cutaneous distribution. This injury
usually occurs between the third and fourth, fourth and fifth,
or fifth and sixth cervical vertebrae, and it may be accompanied
by bruising of the spinal medulla and extravasation of blood
into or around the spinal medulla (Fig. 162). The resulting
sensory and motor changes depend on the extent of the lesion.

Bilateral dislocations are always accompanied by serious
injury of the spinal medulla, and, when they affect any of the
upper four cervical segments, death is instantaneous, as the
diaphragm (phrenic nerve, C. 3, 4, and 5) and the other muscles
of respiration are all paralysed.

Fracture dislocation, which is a not uncommon injury,
usually occurs in the lumbar or lower thoracic region. The
upper vertebra passes forwards and the spinal medulla is crushed
between its laminae and the upper border of the body of the
vertebra below. A complete transverse lesion of the spinal
medulla generally results, but sometimes the injury is only
partial. It may, at first, be impossible to determine whether
the lesion is complete or only partial, as in the latter case the
amount of paralysis is increased by the pressure of the accom-
panying extravasation of blood. When the injury is incomplete,
gradual improvement occurs as the extravasated blood becomes
absorbed. In these cases the motor changes are usually more
extensive than the sensory changes.

A complete transverse lesion of the spinal medulla is
accompanied by total sensory and motor paralysis of the regions
which are innervated by the segments below the lesion. As the
upper neurone is involved, the paralysed muscles are spastic,
and although they may atrophy from disuse, they do not give
the reaction of degeneration. In the case of the muscles which
are innervated by the actual segment destroyed by the injury,
the lesion is of the lower neurone type. Consequently these
muscles rapidly become atrophied, and the reaction of degenera-
tion is present.

If the injury occurs above the level of the spinal centres for the
bladder and rectum (L. i and 2), voluntary control over these

34

530 THE THORAX AND VERTEBRAL COLUMN

viscera is lost and reflex evacuations occur. If the injury occurs
at or below the level of these centres, the viscera are paralysed
and there is, at first, retention of urine, and, later, a continual
overflow. In many cases, however, these centres are only
partially affected.

A complete hemi-lesion of the spinal medulla causes complete
paralysis of the muscles of the same side of the body which are
innervated by the segments below the lesion. Sensory changes
also occur, but, as all the fibres which convey painful and thermal
sensations and most of those which convey tactile sensations
cross the middle line shortly after they enter the spinal medulla,
these changes are only found on the opposite side of the body.
Muscle sense and joint sense, however, are conveyed by fibres
which ascend on the same side till they reach the medulla
oblongata, where they decussate. Loss of muscle and joint
sense, therefore, is restricted to the paralysed limb. A narrow
zone of anaesthesia is present at the upper limit of the motor
paralysis. In this situation the sensory fibres are involved as
they enter the spinal medulla and the position of the anaesthetic
strip is a certain indication of the site of the lesion. Immediately
above the zone of anaesthesia there is usually a narrow zone of
hyperaesthesia.

Complete destruction of the spinal medulla at the level of the
fifth cervical segment is consistent with life, since the nerve-
supply to the diaphragm (phrenic nerve, C. 3, 4, and 5) is not
at once destroyed. This lesion is accompanied by total paralysis,
of the upper neurone type, of the trunk and all the limbs. The
sensory paralysis does not extend so high on the anterior surface
as it does on the posterior surface of the body. Anteriorly, the
line of anesthesia corresponds to the second costal cartilage, as
the skin above that level is supplied by C. 3 and 4 (Fig. 72).
Posteriorly, the line lies at a higher level, since the posterior
rami of the third and fourth cervical nerves do not extend so
far downwards as their anterior rami (Fig. 3). This condition
is usually followed by an ascending myelitis, which destroys
the spinal centres of the phrenic nerve, causing death in a few
days.

When the sixth cervical segment is destroyed, the muscles
supplied by C. 5, being unopposed, produce a characteristic
attitude. The upper limbs are abducted and laterally rotated
at the shoulder, the forearm is flexed and supinated. An
ascending myelitis usually occurs, and destruction of the fifth

THE SPINAL MEDULLA

} ffi- [(y-Vzr Internal capsule, motor fibres

O ij ^-*^_ ]

• Nucleus of 3rd nerve
-Motor fibres in mid-brain

\- Nucleus of yth nerve
.?~^? Motor fibres in pons

•Nucleus ot i2th nerve
'Decussation of fillet

Motor fibres in medulla oblongata

1 Decussation of pyramids
Fibres of muscle and joint sense
.ascending in posterior column

j_\_Lateral cerebro-spinal tract
(crossed pyramidal)

^Anterior cerebro-spinal tract

"(direct pyramidal)

Afferent fibres conveying muscle
-and joint sense

-Spinal ganglion

Fibres containing painful th
ind tactile stimuli

ermal

and tactile st

FIG. 163. — Diagrammatic Representation of the Chief Motor and Sensory
Tracts in the Central Nervous System. (After Purves Stewart.) The
black lines indicate the paths of the sensory fibres and the dotted lines
indicate the paths of the motor fibres.

532 THE THORAX AND VERTEBRAL COLUMN

segment is indicated by the collapse of the upper limbs upon
the trunk.

In transverse lesions of the spinal medulla occurring between
the fourth cervical and the second thoracic segments the limit
of anaesthesia on the anterior surface of the body is placed at
the level of the second costal cartilage (p. 530). The distribution
of the areas of altered sensibility in the upper limbs gives an
indication of the exact level at which the spinal medulla is
injured. When a lesion occurs below the second segment in the
thoracic region, the upper limit of the anaesthesia corresponds to
a horizontal line drawn round the trunk at the level of the
terminal branches of the intercostal nerve which arises from the
injured segment. As the thoracic nerve-roots pass downwards
before they leave the vertebral canal, and as the nerves sub-
sequently descend for some distance before they terminate
(p. 240), the site of the injury to the vertebral column is placed
at a much higher level than the upper limit of the anaesthesia.

A complete transverse lesion of the spinal medulla in the lower
thoracic region is accompanied by total motor and sensory
paralysis of both lower limbs. Although the lesion in the
vertebral column is above the level of the transpyloric plane,
the muscles of the abdominal wall, which are supplied by the
seventh to twelfth thoracic nerves, are little affected, and the
cutaneous sensibility is altered only in the lowest part of the wall.
Reflex evacuations of the bladder and rectum occur, as the lesion
is above the level of the spinal centres for these viscera (p. 529).

In complete transverse lesions above the level of the seventh
thoracic segment all the muscles of the abdominal wall are
paralysed and the condition of meteorism supervenes ; owing
to the absence of the expulsive force, gas accumulates in the
alimentary canal and the abdomen becomes greatly distended.

Fracture dislocation in the lumbar region of the vertebral
column involves the cauda equina. All the nerve-roots of the
cauda are rarely affected, and the alteration of sensibility in the
saddle-shaped area supplied by the third sacral nerves (Fig. 116)
is usually asymmetrical. As the condition arises from a root
injury, the area of epicritic loss is smaller than the area of
protopathic loss (p. 97). In these cases the bladder and
rectum are often affected, but the paralysis is rarely complete.

Fracture of the Articular Processes alone does not necessarily
give rise to symptoms of nerve pressure.

Surgical Approach to the Spinal Medulla. — It may be

THE SPINAL MEDULLA 533

necessary to expose the spinal medulla in order to remove the
cause of pressure, when it is being compressed, or to divide the
posterior nerve-roots, in intractable neuralgia (the " crises " of
locomotor ataxia).

A vertical incision is made in the median plane and is carried
down to the vertebral spines. The muscles attached to the
spines and laminae are elevated on both sides, and this step may
give rise to severe haemorrhage. The bleeding, however, may
be controlled by packing tightly with gauze and forcibly
retracting the muscular masses in a lateral direction. The
supra- and inter-spinous ligaments of the vertebra selected are
cut and the lamina on each side is divided with an osteotome.
The instrument is applied with its cutting edge at right angles
to the inferior border of the lamina. In this way there is no
danger of cutting into the root of the vertebral arch (pedicle),
and, if the instrument slips when the division of the lamina is
completed, the spinal medulla cannot be injured.

After both laminae have been divided, the ligamenta flava
(p. 527) are cut across, and the vertebral arch may be removed.
Additional laminae can then be removed with bone forceps.
Some loose fatty tissue containing numerous small veins is
exposed on the surface of the dura mater. The haemorrhage
from these veins may be so great as to necessitate a two-stage
operation.

The dura mater is incised, and as the arachnoid may be
injured at the same time, cerebro -spinal fluid may escape in
company with subdural fluid. To prevent too great an outflow
the head-end of the table should be depressed.

When the operation has been completed, the cut edges of
the dura mater are carefully united (p. 536) and the thick muscular
flaps are replaced.

Development of the Nervous System and the Vertebral
Column. — During the second week of intra-uterine life, a
longitudinal furrow, termed the neural groove, appears on the
dorsal aspect of the embryo. The walls and floor of this groove
are formed by a thickening of the surface ectoderm. At a
slightly later stage the margins of the groove unite and it
becomes converted into the neural tube, which subsequently
gives origin to the whole of the nervous system. At first the
dorsal part of the neural tube is continuous with the surface
ectoderm, but the two soon become separated by mesoderm,
which grows in from each side.

34 a

534 THE THORAX AND VERTEBRAL COLUMN

The mesoderm which surrounds the neural tube forms the
vertebral column and the membranes of the brain and the
spinal medulla. Two bars of cartilage appear in each segment,
one at each side of the neural tube,, and grow backwards to form
the vertebral arch. They fuse with one another dorsally during
the fourth month and enclose the neural tube, surrounded by
a sheath of mesoderm; which becomes differentiated into the
dura mater, arachnoid, and pia mater.

The cartilaginous bars may fail to fuse on the dorsal aspect
of the neural tube. This condition, which is termed spina
bifida, most commonly occurs in the lumbo-sacral region and
may affect several consecutive segments. It is usually
associated with anomalies of the spinal medulla and its
membranes, but it may occur alone — spina bifida occulta.

The anomalies associated with spina bifida are subdivided
into several varieties, and the precise nature of the anomaly can
rarely be determined until the sac of the tumour which it forms
is opened.

1. In a Meningocele the spinal medulla is normal in
development and position, and it possesses a complete covering
of pia mater. The arachnoid and the dura mater form a hernia,
filled with cerebro-spinal fluid, which projects backwards through
the deficiency in the vertebral arches and forms a tumour under
the skin of the back. Sometimes the dura mater is deficient
dorsally and the sac of the tumour is formed solely by the
arachnoid (Fig. 164, a) ; at others, the arachnoid maintains
its normal relationship to the spinal medulla and the sac is
formed by the dura mater alone.

2. The Myelo-Meningocele differs from a meningocele in
that the spinal medulla, though normally developed and covered
by pia mater, herniates backwards into the sac of the tumour.
Both the spinal medulla and the nerve-roots arising from it may
be adherent to the inner wall of the sac (Fig. 164, b).

3. In a Myelo-Cystocele the central canal of the spinal
medulla is enlarged in a backward direction, and its thin dorsal
wall, which retains its primitive embryonic structure, projects
through the deficiency in the vertebral arch. The dura mater
is said to be completely absent over the dorsal surface of the
tumour and the arachnoid is in contact with the skin (Fig. 164, c).

4. In a Myelo-Cysto-Meningocele the condition is similar
to (3), but, in addition, the subarachnoid space is greatly dilated
and forms an arachnoidal meningocele.

THE SPINAL MEDULLA

535

Note. — In arachnoidal meningoceles, whether simple or
complicated by myelo-cystoceles, fine strands are frequently

FIG. 164. — Diagram illustrating some of the Congenital Anomalies of the
Vertebral Column and Spinal Medulla.

a. Meningocele. | d. Myelo-cysto-meningocele.

b. Myelo-meningocele. e. Myelocele, transverse section.

c. Myelo-cystocele. | f. Myelocele, longitudinal section.

The dotted line represents the pia mater, the red line the arachnoid, and the heavy
black line the dura mater.

«, l>, c and d show the un-united vertebral arches on transverse section.

In e and f the vertically shaded areas represent the skin.

In f the central canal of the spinal medulla is seen opening on the surface at the
upper and lower limits of the myelocele.

found in the subarachnoid space, connecting the arachnoid to

the pia mater. These strands may be not unlike spinal nerves.

5. A Myelocele is due to an arrest of development at the

34 &

536 THE THORAX AND VERTEBRAL COLUMN

time of the closure of the primitive neural groove. In a limited
area the edges of the groove fail to unite and the central canal
of the spinal medulla opens on the dorsal surface of the foetus.
The exposed area, which is elliptical in shape and brownish in
colour (the " area medullo-vasculosa " of Recklinghausen),
consists of a flattened zone of neuroglia containing a few nerve-
cells. Rudimentary anterior and posterior nerve -roots are
attached to the ventral surface of the undeveloped part of the
spinal medulla. Complete paralysis is present on both sides of
the body below the level of the anomaly. As the central canal
of the spinal medulla opens on the surface (Fig. 164, /),
septic infection rapidly occurs and death results shortly after
birth. These cases are therefore unsuitable for treatment.

In the other varieties described the sac may be exposed by
a longitudinal incision, which divides to surround the tumour.
When the tumour is situated in the sacral region, a transverse
incision may be employed in order to keep the wound as far as
possible from the anus. On the dorsal aspect of the tumour
the skin is extremely thin over an area of variable extent, and
this pellicle is enclosed by the incision. The skin is undercut
on each side and the wall of the sac is opened. The subsequent
treatment depends on the precise nature of the tumour.

In simple meningocele, part of the sac is removed and the
edges are carefully approximated. In myelo-meningocele the
spinal medulla and nerve-roots are freed, if adherent to the
inside of the sac, and are then replaced within the vertebral
canal. Part of the sac is removed and the wound is closed in
two layers — sac wall and skin.

In order to prevent leakage of the cerebro-spinal fluid, the
cut edges of the sac wall are turned backwards and their inner
surfaces are carefully stitched to one another. In myelo-cysto-
meningocele, part of the sac may be ligatured and removed, but,
in this case also, great care must be taken to prevent subsequent
leakage of cerebro-spinal fluid.

Similar deformities occur in connection with the skull and
the membranes of the brain, but they are much rarer. Cranial
meningocele, encephalocele, and hydr-encephalocele correspond
respectively to spinal meningocele, myelo-meningocele, and
myelo-cysto-meningocele. They are usually found in the
median plane, and their commonest site is below the external
occipital protuberance in the occipital region.

A hydr-encephalocele in the occipital region contains the

THE SPINAL MEDULLA 537

herniated dorsal wall or roof of the fourth ventricle. When the
tumour occurs in the line of the frontal (coronal) suture it
contains a diverticulum from the lateral ventricle.

The sac of the tumour is covered by skin, normal or thinned,
and it consists of arachnoid, save in simple meningoceles, where
the dura mater may be present. The sac is opened in order to
ascertain whether it contains any brain tissue (encephalocele or
hydr-encephalocele) or merely cerebro-spinal fluid (meningocele).
If brain tissue is found and cannot be reduced within the skull,
it may be ligated and removed. In suturing the cut edges of
the membranes care must be exercised to prevent subsequent
leakage of the cerebro-spinal fluid.

INDEX.

Abdominal cavity, 276
wall, anterior, 237
arteries of, 252
incisions in, 247
lymph vessels of, 243
nerves of, 240, 250
surface landmarks of, 237
veins of, superficial, 243
posterior, 269
Abscess, alveolar, 145, 184
cerebellar, 227
ischio-rectal, 373
of liver, 308, 309
of lung, 283
mammary, 26
parotid, 177
popliteal, 446
psoas, 270, 272

spread of, 272, 273
retro-cascal, 286
retro-pharyngeal, 114, 191, 520
subdural, 216
of temporal lobe, 231
Adenoids, 190
Air-cells, ethmoidal, 194, 201

mastoid, 214
embolus, no
sinus, frontal, 194, 200

maxillary, 194, 195
Alcock's canal, 373
Allantois, 287

Alveolo-dental periosteum, 184
Anal canal, 369
anomalies of, 381
blood-supply of, 370
examination of, 372
lymph vessels of, 372
muscular coat of, 369
nerve-supply of, 371
Ankle, anastomosis round, 482

Ankle (contd.) —

joint. See Joint, ankle
region, 477

injuries in, 485

spread of tuberculous disease, 482
surface landmarks of, 477
Anus, imperforate, 381
Aorta, arch of, 512

thoracic, descending, 514
Appendix, vermiform. See Pro-
cess, vermiform
Arachnoid, 225
Area medullo-vasculosa, 536
Arm, deep fascia of, 38
intermuscular septa of, 38
muscular landmarks of, 38
Artery or Arteries —
of abdominal wall, 253
alveolar, inferior, 180, 181
articular, of knee. See A., geni-

cular

auricular, posterior, 219
axillary, 32

aneurism of, 34
compression of, i
ligature of, 33

azygos. See A., genicular, middle
brachial, 42
branches of, 43
ligature of, 43, 44
carotid, common, 116, 119

ligature of, 119, 120
external, 120

ligature of, 121
internal, 225

centralis retinas, 208, 209
cervical, ascending, 141

transverse, 126
ciliary, 208
circumflex, humeral, 18, 34, 39

539

540

INDEX

Artery or Arteries (contd.) —
circumflex (contd.) —

iliac, deep, 253

ascending branch, 249
superficial, 253, 399

lateral, 409

medial, 410
coeliac, 296
colic, left, 340

middle, 336

right, 336
coronary, of lips. See A., labial

of stomach. See A., gastric,

left
cremasteric. See A., spermatic,

external

crico-thyreoid, 122
cystic, 312

dental. See A., alveolar
digital, 86
dorsales lingua?, 145
dorsalis pedis, 472, 492

penis, 386
epigastric, inferior, 253, 263

superficial, 253, 399

superior, 503

facial. See A., maxillary, ex-
ternal
femoral, 406

axial anastomosis of, 408

ligature of, 407, 408, 412
frontal, 219
gastric, left, 296

right, 296

short, 297

gastro-duodenal, 296
gastro-epiploic, 296, 297
genicular, 445

middle, 463
gluteal, inferior, 418

superior, 416

ligature of, 416
h»morrhoidal, inferior, 370

middle, 370

superior, 370
hepatic, 296
ileo-colic, 333
interosseous, common, 71

dorsal, 71

volar, 71
intestinal, 324
labial, 175

laryngeal, superior, 121
lingual, 122, 145

ligature of, 122, 145, 188
of mammary gland, 25

Artery or Arteries (contd.) —
mammary, internal, 503

ligature of, 503
maxillary, external, 122, 147
in face, 174, 198

internal, 180, 181, 182
meningeal, middle, 181, 230

branches of, 231, 232

ligature of, 231
mesenteric, inferior, 341

superior, 323
musculo-phrenic, 503
obturator, 411

abnormal, 405
occipital, 122, 219

ramus descendens, 136
ophthalmic, 208
ovarian, 393
palatine, 193

palmar arch. See A., volar arch
pancreatico - duodenal, inferior,
323

superior, 296
perforating, 410
peroneal, 476
plantar, lateral, 491

medial, 491
popliteal, 444, 463

branches of, 445

ligature of, 445
profunda brachii, 39, 43

cervicis, 137

femoris, 409
pudendal, external, superficial,

253, 399
deep, 409

internal, 378

pyloric. See A., gastric, right
radial, 72, 92

recurrent branch, 43

wounds of, 72
renal, 351

supernumerary, 352
sacral, middle, 370
scapular, transverse, 126
sigmoid, 342
spermatic, external, 257

internal, 257
splenic, 296
to sterno-mastoid, 135
subclavian, 129, 131, 142
subscapular, 34
superficialis volae, 72
supra-orbital, 219
supra-scapular. See A., scapular,
transverse

INDEX

Artery or Arteries — (contd.)
temporal, superficial, 219
thoracic axis. See A., thoraco-

acromial
lateral, 31
superior, 33
thoraco-acromial, 30
thyreo-cervical trunk, 143
thyreoid, inferior, 142, 143, 167

ligature of, 168

superior, 121, 167

ligature of, 168

thyroid axis. See A., thyreo-
cervical trunk
tibial, anterior, 471
posterior, 475

ligature of, 476
ulnar, 71

wounds of, 72
ulnar collateral, 43
uterine, 394
vertebral, 140

ligature of, 140
volar arch, deep, 92

superficial, 86
Ary-epiglottic fold, 156
Asterion, 218
Astragalus. See Talus
Atlas, 519

anterior arch of, 190
transverse process of, 107
Auditory apparatus, 209

tube, 190, 212
Auricle, development of, 210
Axilla, 28

walls of, 28, 31, 32
Axillary sheath, 32, 113

Bennett's fracture, 80
Bent arm, 50
Bezold's mastoiditis, 215
Bile duct, 314

exploration of, 306

surgical approach to, 314, 315,
316

termination of, 316
Biliary colic, 312
Bladder, urinary, 358

blood-supply of, 361

distention of, 359

extroversion of, 380

hypertrophy of, 361

nerve-supply of, 362

referred pain, 362

spinal centres for, 529
Blepharo-spasm, 204

Border cells, 215
Brachial plexus, 37, 95

branches of, 96

injuries of, 98

surgical approach to, 127
Brain, 228

exploration of, 231

ventricular system of, 225
Branchial arches, 148
arteries of, 149

cysts, 151

fistula, 150
Broca's area, 229
Bryant's line, 425
Bulbo-urethral glands, 384
Bulla ethmoidalis, 194
Burns' ligament, 402
Bursa or Bursae —

under glutaeus maximus, 415,
416

infra-patellar, 449

round knee-joint, 448

popliteus, 449

pre-patellar, 448

subacromial, 13

ulnar, 88

Caecum, 329

prolapse of, 329

removal of, 338
Calcaneus, 478

fracture of, 490

ossification of, 489

surgical approach to, 488

tuberculous disease of, 488
Camper, fascia of, 240
Canal, adductor, 412

femoral, 402

inguinal, 253
Capitate bone, 80
Caput succedaneum, 221
Carotid sheath, 114
incisions into, 121
relations of, 115

tubercle, 107
Carpal ganglion, 91
Carpus, ossification of, 79

resection of, 80
Carrying angle, 51
Cartilage arytenoid, 155

corniculate, 155

cricoid, 155

Meckel's, 149

semilunar. See Joint, knee,
menisci of

thyreoid, 154

542

INDEX

Cauda equina, 527
Cephal-haematoma, 221
Cerebello-pontine angle, 235

tumours of, 235
Cerebral hemisphere, 228
Cerebro-spinal fluid, 222
Cervical caries, 113, 520

sinus, 150
Cervix uteri, 390

stenosis of, 390
Chemosis, 235
Choanae, 190
Cholecystectomy, 312
Cholecyst-enterostomy, 313
Chopart's amputation, 484
Chordee, 385
Chorioid, 209
Circumcision, 386
Cisterns, subarachnoid, 225

cerebello-medullary, 227
Clavicle, i, 10

dislocations of, 9

examination of, n

excision of, u

fractures of, n
in children, 12

ossification of, 10
Clitoris, 397
Codman's bursitis, 14
Colic, biliary, 312

renal, 257, 354
Colics' fascia, 240

fracture, 77
Coloboma facialis, 192
Colon, ascending, 334
removal of, 338

blood-supply of, 336, 340, 341

descending, 340

iliac, 341

lymph vessels of, 338, 340

pelvic, 341

removal of, 343

transverse, 335
Colotomy, inguinal, 248, 343
Colporrhaphy, 389
Columns, rectal, 370
Compound palmar ganglion, 88
Conchae, 190, 194
Conjoined tendon. See Falx in-

guinalis aponeurotica
Conjunctiva, 204
Conus elasticus, 155
Cornea, 208

ulcer of, 204

Costo-coracoid membrane, 30
Costo- trans versectomy, 514

Cowper's glands. See Bulbo-

urethral glands
Coxa valga, 427

vara, 427

Crest, urethral, 383
Cretinism, 169
Cricoid cartilage, 107
Cuneiform tarsectomy, 495
Cut throat, 159
Cystocele, 389
Cystotomy, 359

Dactylitis, tuberculous, 93
Decompression, suboccipital, 227

temporal, 231
Dens, 519

tuberculous disease of, 519
Dentigerous cysts, 184
Dentition, 184
Diaphragm, pelvic, 356

urogenital, 378
Diplopia, 207
Dorsal subaponeurotic space, 91

incision into, 92

infection of, 91
Drop wrist, 102
Duct, bile, 314

cystic, 313

ejaculatory, 367

hepatic, common, 314

naso-lacrimal, 206

pancreatic, 318

termination of, 316

parotid, 176

submaxillary, 144

vitello-intestinal, 287
Ductus defer ens, 257
Duodeno-jejunal flexure, 306
Duodenum, 303

surface marking of, 307

ulcer of, 304

perforation of, 286
Dupuytren's contraction, 83
Dura mater, 223

Ecchymosis, subconjunctival, 222

Elbow joint. See Joint, elbow

Elbow region, 44

bony landmarks of, 44
tuberculous disease in, 59

Eminence, intercondylar, 459

Empyaema, 283, 504

Encephalocele, 536

Epididymis, 265, 267
development of, 267

Epiglottis, 155, 161

INDEX

543

Epiphora, 198, 205
Epispadias, 380
Epistaxis, 221, 222
Epitympanic recess, 212
Ep-oophoron, 394
Erb-Duchenne paralysis, 99
Eustachian tube. See Auditory

tube

Exophthalmos, 222
Extensor tendons, insertion of, 92

synovial sheaths of, 91
Eye, 203
Eyeball, 206, 208

chambers of, 209

check ligaments of, 206

suspensory ligament of, 206
Eyelids, 203

blood-supply of, 204

lymph vessels of, 204

Face, 170

bony landmarks of, 170

carbuncle of, 175

development of, 191

incisions in, 178

naevus of, 174

nerves of, cutaneous, 172

oedema of, 171

plastic operations on, 172

skin of, 171

Facio-hypoglossal anastomosis, 178
Falx cerebri, 223

inguinalis aponeurotica, 245
Fascia, axillary, 28

bulbi, 206

cervical, deep, in

clavi-pectoral, 29

of Colles, 376

cremasteric, 255

iliaca, 271

lumbo-dorsal, 269

pectoral, 28
exposure of, 28

pelvic, parietal, 355
visceral, 357

peri-nephric, 271

pretracheal, 114

prevertebral, in

of Scarpa, 240

spermatic, external, 255
internal, 255

of thigh, 400

trans versalis, 252
Femur, condyles of, 443
fracture of, 466

examination of, 426

Femur (contd.) —
fractures of, 438, 439
supra-condylar, 466
neck of, 427
fractures of, 438
injuries of, 427
surgical approach to, 436
ossification of, 420, 451
separation of epiphysis, 466
shaft of, fractures of, 439, 440
osteo-myelitis of, 437
surgical approach to, 437
Fibula, fracture of, 477. See also

Pott's fracture
ossification of, 468, 481
surgical approach to, 477
Filum terminal e, 527
Fingers, congenital contraction of,

83

development of, 95
fibrous sheaths of, 83
incisions on, 92
synovial sheaths of, 88
Fistula in ano, 374
Flat-foot, 465, 493
Flexure, colic, left, 339

resection of, 340
right, 335

resection of, 338
Fold, ary-epiglottic, 156
patellar synovial, 452
Fontanelles, 221
Foot, arches of, 475
longitudinal, 492
transverse, 493
architecture of, 492
deformities of, 494
gangrene of, 492
joints of, 483
surface landmarks of, 477
Foramen, epiploic (of Winslow), 279
Forearm, bony landmarks of, 65
bones of, fracture of, 68

surgical approach to, 73
muscular landmarks of, 66
Fossa, caecal, 330
cranial, anterior, 222

surgical approach to, 232
middle, 222

surgical approach to, 230
posterior, 222
contents of, 235
surgical approach to, 227
cubital, 45
duodenal, 307
ischio-rectal, 373

544

INDEX

Fossa (contd.) —

navicularis, 384

ovalis, 401

ovarica, 393

supra- tonsillar, 188
Frontal bone, fracture of, 200

sinus, 200

empyaema of, 200
Fron to-nasal process, 191

Galea aponeurotica, 219
GaU bladder, 311

fundus of, 313

nerve-supply of, 312

referred pain, 312

surgical approach to, 251
Ganglion, otic, 214

semilunar, 233
removal of, 234
sequelae of, 235

spheno-palatine, 191, 194, 233
Gasserian ganglion. See Ganglion,

semilunar
Gastrectomy, 300
Gastric ulcer, 283
Gastro-enterostomy, anterior, 302

posterior, 301

Genito- urinary organs, anomalies of,
380

development of, 379
Genu valgum, 463

operation for, 438

varum, 465
Gerota's space, 271
Glabella, 170
Glaucoma, 209
Glossitis, acute, 187
Glottis, spasm of, 161
Gridiron incision, 248
Gubernaculum testis, 257
Gyrus, central, anterior, 229
posterior, 229

Haematemesis, 311

Haemorrhage, subconjunctival, 204,

205, 222
Haemorrhoids, external, 371

internal, 311, 371
Hallux rigidus, 498

valgus, 498

Hamate bone, hook of, 66
Hammer toe, 498
Hamulus, pterygoid, 193
Hand, bony landmarks of, 80

lymph vessels of, 82
Harelip, 192

Head, bony landmarks of, 218
Heart, 510
apex beat of, 502
area of superficial dulness, 510
suture of, 511
Heister, value of, 314
Hernia, congenital, 287
diaphragmatic, 288
femoral, 403

strangulated, 405
surgical approach to, 404
gluteal, 418
inguinal direct, 263
oblique, 259, 261, 263
in female, 264
funicular type, 259
interstitial, 260
old-standing, 263
pro-peritoneal, 260
superficial, 261
vaginal type, 259
radical cure of, 261
obturator, 411
umbilical, 288
Herpes Zoster, 240
Hesselbach, triangle of, 263
Key's amputation, 484

ligament, 402
Hiatus tendineus, 412
Highmore, antrum of. See Maxil-
lary sinus
Humerus —
diastasis of, 58
distal extremity, 51
ossification of, 55
surgical approach to, 60
epicondyle, medial, 44
fracture of, 63
ossification of, 56
fractures of, 42

non-union of, 41
proximal extremity of, 4
ossification of, 15
resection of, 39
surgical approach to, 39
shaft of, examination of, 41
surgical neck, fracture of, 23
tubercles of, 3

greater, fracture of, 23
Hunter's canal. See Canal, ad-
ductor

Hutchinson's teeth, 184
Hydatids of Morgagni, 267
Hydr-encephalocele, 536
Hydrocele, 267
congenital, 259

INDEX

545

Hydrocele (contd.) —

encysted, of round ligament, 264
of spermatic cord, 260

intermittent, 259

radical cure of, 268

surgical approach to, 262
Hydrocephalus, 120, 221

acquired, 227

congenital, 226
Hyoid bone, 107

development of, 149
Hyperacousis, 214
Hypophysis, tumours of, 202, 225
Hypospadias, 380
Hypothenar eminence, 84
Hysterectomy, 395

Ileo-pelvic-colostomy, 327, 345
Ileum, 322

identification of, 322, 323
Incus, 211, 214
Infra-orbital foramen, 171
Inguinal ring, abdominal, 253

subcutaneous, 239, 254
Intercostal spaces, 503
Intestinal stasis, 325
Intestine, small, 322

development of, 345

lymph vessels of, 324

nerves of, 325

referred pain, 325

stricture of, 325

structure of, 325
Intussusception, ileo-caecal, 334

ileo- colic, 334
Iridectomy, 209
Iris, 209

Jackson's veils, 329
Jejunum, 322

identification of, 322, 323
Joint or Joints —

acromio-clavicular, 10
ankle, 481

arthrodesis of, 488

level of, 480

ligaments of, 481

sprains of, 485

surgical approach to, 487
calcaneo-cuboid, 484
carpal, 78
costo- trans verse, 513

ligaments of, 513
costo- vertebral, 513
elbow, 51

aspiration of, 55

dislocations of, 60

Joint or Joints (contd.) —

elbow, dislocations of (contd.) —
complications of, 62
reduction of, 61
fractures around, 62
fractures into, 51
ligaments of, 52, 53
surgical approach to, 64
synovial membrane of, 54
of foot, 483
hip, 419

aspiration of, 424
dislocation of, congenital, 428
pathological, 432
traumatic, 430, 431
reduction of, 431
examination of, 426
excision of, 434
function of, 426
surgical approach to, 432, 434
tuberculous disease of, 421
attitude in, 435
intra-pelvic spread of, 424
interphalangeal, line of, 81
knee, 452

aspiration of, 443
dislocation of, 468
drainage of, 460
excision of, 462
inspection of, 461
ligaments of, 454
menisci of, 455
injuries of, 456
surgical approach to, 458
surgical approach to, 460
synovial membrane of, 452
tuberculous disease, 459
metacarpo-phalangeal, line of, 81
occipito-atloid, 519
radio-carpal, 75
radio-ulnar, distal, 75

proximal, 51
shoulder, 15

adhesions in, 17
aspiration of, 18
capsule of, 15
dislocations of, 20
complications of, 23
reduction of, 22
ligaments of, 15
surgical approach to, 19
synovial membrane of, 17
sterno-clavicular, 6
dislocations of, 9
ligaments of, 9
movements at, 9

35

546

INDEX

Joint or Joints (contd.) —
talo-calcanean, 483
talo-calcaneo-navicular, 484
temporo-mandibular, 179

movements at, 180
tibio-fibular, distal, 482
wrist, 75

articular disc of, 76

aspiration of, 76

level of, 76

ligaments of, 76

surgical approach to, 79

Kidneys, 349, 350

calculi in, 351

excision of, 349, 350

movable, 353

position of, 346

structure of, 351

surgical approach to, 273

tuberculous, 350
Klumpke paralysis, 98, 100
Knee-joint. See Joint, knee
Knee, region of, 441
injuries in, 466
landmarks in, 441
referred pain, 406
Knuckles, 81
Kyphosis, 524

Lacertus fibrosus, 45
Lacrimal ducts, 205

gland, 205

puncta, 205

sac, 205

Lambdoidal suture, 218
Laryngeal prominence, 107
Laryngismus stridulus, 161
Laryngoscopic examination, 157
Laryngotomy, 162

tube, 162
Larynx, 154

excision of, 162

lymph vessels of, 158

polypi, 158

upper opening of, 156

ventricle of, 157

vestibule of, 157
Leg, fascia of, 469

septa, intermuscular, 469

surface landmarks of, 468
Lens, crystalline, 209
Leucoma, 209
Ligament or Ligaments —

of ankle-joint, 481

annular, 53, 65
of wrist. See Lig., carpal

Ligament or Ligaments (contd.) —
broad, of uterus, 387
calcaneo-fibular, 481
calcaneo-navicular, plantar, 484,

492
carpal, dorsal, 90

transverse, 82
check, of eyeball, 206
of Cooper, 25
coraco-acromial, 13
coraco- clavicular, 10
of costo- transverse joint, 513
cruciate, of ankle, 470

of knee, 458

rupture of, 459
deltoid, 481
of elbow-joint, 52, 53
falciform, 277
flavum, 527
gastro-splenic, 281
of Gimbernat. See Lig., lacunar
gleno-humeral, 18
ilio- femoral, 420
inguinal, 244
interclavicular, 9
of knee-joint, 454
laciniate, 471
lacunar, 244
lieno-renal, 281

of metacarpo-phalangeal joint, 93
orbicular. See Lig., annular
patella?, 454
phreni co- colic, 286
plantar, 484

of Poupart. See Lig., inguinal
pubo-prostatic, true, 357
round, of uterus, 391
sterno-clavicular, 8
stylo-man dibular, 116
suspensory, of axilla, 30

of eyeball, 206

of ovary, 387
talo-fibular, 481

of temporo-mandibular joint, 180
teres, 277
transverse, of ankle, 469

of atlas, 519

of hip, 420

of shoulder, 18
utero-sacral, 391
of wrist-joint, 76
Limb, lower, measurements, 424
Line, temporal, superior, 218
Linea alba, 238

incisions through, 247
closure of, 248

INDEX

547

Linea (contd.) —
semicircularis, 247
semilunaris, 239
Lineae transversae, 239, 246
Lingual dermoids, 152
Lip, upper, development of, 192
Lipoma arborescens, 54, 453
Lisfranc's amputation, 484
Lithotomy, lateral, 379
Little's disease, 232
Liver, 307

abscess of, 308, 309

drainage of, 309
blood-vessels of, 310
development of, 311
lymph vessels of, 244
Lordosis, 435, 524
Ludwig's angina, 145
Lumbar puncture, 527
triangle, 269
upper, 269
Lunate bone, 80
Lungs, 509

surface relations of, 508
Lymph glands —

auricular, anterior, 176, 204

abscess of, 177
axillary, apical, 30, 32, 36

central, 35

cervical, superficial, no
deep, 132

surgical approach to, 134,

141

of colon, 338, 340
epitrochlear, 44
infra-clavicular, 30
mastoid, no, 215
occipital, no
parotid, 176

abscess of, 177
pectoral, 31, 35
popliteal, 446
retro-pharyngeal, 114
of stomach, 299
subinguinal, deep, 400

superficial, 400
submaxillary, 146
examination of, 143
removal of, 147
submental, 152

removal of, 152
subscapular, 35
tonsillar, 133
Lymph vessels —

of abdominal wall, 243
of anal canal, 372

Lymph vessels (contd.) —
of eyelids, 204
of hand, 50, 82
laryngeal, 158
of mammary gland, 26
of nasal pharynx, 190
of penis, 387
of rectum, 372
of spleen, 321
of stomach, 298
of testis, 257
of tongue, 1 86
of tonsil, 189
of uterus, 394
of vagina, 394

M'Burney's point, 248
Main en griff e, 103
Malleolus, lateral, 477

medial, 478
Malleus, 211, 214
Mammary gland, 25

abscess of, 26

development of, 24

extent of, 25

lymph vessels of, 26
Mandible, angle of, 171

condyle of, 171

coronoid process of, 171

dislocation of, 180

excision of, 182

fracture of, 180

operations on, 181
Mandibular arch, 148, 191
Mastoid antrum. See Tympanic
antrum

process, 107

development of, 210
Maxilla, removal of, 198
Maxillary process, 192

sinus, 195

empyaema of, 195
malignant tumours of, 197
surgical approach to, 196
Meatus, acoustic, external, 210

development of, 209

foreign bodies in, 211

nerve-supply of, 211
Meckel's cartilage, 149

diverticulum, 327
Mediastinum, 505

posterior, approach to, 513
Medulla oblongata, 235
Membrane, thyreo-hyoid, 155

tympanic, 210, 211
Meningitis, basal, 225

548

INDEX

Meningocele, 534
cranial, 536
treatment of, 536
Mental foramen, 171
protuberance, 180
Mesentery, 279, 322

of vermiform process, 331
Meso- colon, pelvic, 341
transverse, 278, 336
Mesosalpinx, 387
Mesovarium, 387
Metacarpal bones, 81
fracture of, 81
ossification of, 93
resection of, 93
Metatarsal bones, first, 498

resection of, 497
ossification of, 497
tuberculous disease of, 497
Motor area, 229
Mouth, development of, 191
Muscle or Muscles —

abductor digiti quinti, 84
pollicis brevis, 84

longus, 67, 73
adductor brevis, 410
longus, 410
magnus, 410
pollicis, 89
anconaeus, 73
biceps, 18, 38, 41

femoris, 441
brachialis, 41
brachio-radialis, 66, 73
branchial, 149
buccinator, 176
bulbo-cavernosus, 377
complexus. See M., semispinalis

capitis

compressor urethrae. See M.,
transversus perinei, deep
constrictor, of pharynx, 144, 190
coraco-brachialis, 38, 41
cremaster, 255
crico-thyreoid, 114, 149, 161
deltoid, 3, 14

depressor, of hyoid bone, 154
digastric, 144
dilatator pupillae, 125
ejaculator urinae. See M., bulbo-
cavernosus
epicranius, 219
erector penis. See M., ischio-

cavernosus

extensor carpi radial is brevis, 66,
73

Muscle or Muscles (contd.) —
extensor carpi radialis (contd.)-

longus, 66, 73
ulnaris, 73

digitorum brevis, 478
communis, 67, 73, 92
longus, 471
hallucis longus, 471
pollicis brevis, 73

longus, 68, 73

of facial expression, 149, 178
flexor carpi radialis, 67, 69

ulnaris, 66, 67, 69
digiti quinti brevis, 84
digitorum longus, 475
profundus, 73, 84
sublimis, 69, 84
hallucis longus, 475
pollicis brevis, 84

longus, 73
gastrocnemius, 474
genio-glossus, 148
genio-hyoid, 148
glutaeus maximus, 415
medius, 416
minimus, 416
gracilis, 410
hyo-glossus, 144, 154
of hypothenar eminence, 84
iliacus, 271
infra-spinatus, 15
intercostal, 503
interosseous, of hand, 90
ischio-cavernosus, 377
of larynx, 150
latissimus dorsi, 37
levator ani, 356

glandulaa thyreoideaa, 167

development of, 169
palpebrae superioris, 206
scapulae, 12, 112, 130
longissimus capitis, 136
longus colli, 112
lumbrical, 84
masseter, 181
of mastication, 149, 181
mylo-hyoid, 144
oblique, external, 244
. inferior, 138

of eye, 206

internal, 244

superior, 138

of eye, 206

obturator externus, 410

internus, 356
omo-hyoid, in, 115, 126, 154

INDEX

549

Muscle or Muscles (contd.) —
opponens pollicis, 84

digit! quinti, 84
of orbit, 206

tenotomy of, 208
palmaris longus, 67
pectineus, 410
pectoralis major, 29

minor, 29
peronaeus brevis, 473

synovial sheath of, 474

longus, 473, 493

synovial sheath of, 474
tuberculous disease of, 474

tertius, 471
piriformis, 474
platysma, 108
popliteus, 447
pronator quadratus, 73

teres, 68

psoas major, 270
pterygoid, external, 181

internal, 181

quadratus lumborum, 270
quadriceps femoris, 408
recto- urethralis, 357, 369
rectus abdominis, 246
sheath of, 246

capitis posterior major, 138

inferior, 206

lateralis, 207

median's, 207

superior, 206
rhomboid major, 12

minor, 12
sartorius, 409
scalenus anterior, 112, 130

medius, 112, 130

posterior, 130
semispinalis capitis, 136

cervicis, 137
serratus anterior, 31

paralysis of, 98
soleus, 469, 474
splenius, 112, 130
stapedius, 214
sterno-hyoid, 154
sterno-mastoid, 107, 116
sterno-thyreoid, 154
stylo-glossus, 148, 154
subclavius, 37
supinator, 73

longus. See M., brachio-radialis
supra-spinatus, 14
tarsal, inferior, 205
temporal, 181

Muscle or Muscles (contd.) —
tensor tympani, 214
veli palatini, 193
teres major, 37

minor, 15

of thenar eminence, 84
thyreo-hyoid, 154
tibialis anterior, 469, 471, 479

posterior, 475, 492
trachelo-mastoid. See M., longis-

simus capitis

transversus abdominis, 245
perinei, deep, 378
superficial, 377
trapezius, 6
triceps, 38

surae, 474
Myelocele, 535
Myelo-cystocele, 534
Myelo-cysto-meningocele, 534
Myelo-meningocele, 534
Myx oedema, 169

Nasal bone, fracture of, 195

septum, 189

deviation of, 194
Nasion, 170
Naso-lacrimal duct, 206

development of, 192
Navicular bone, tuberosity of,

479

of hand, 80
Nebulas, 209
Neck, 107

anterior median line, 150

development of, 148

surface landmarks of, 107
Nelaton's line, 424
Nephropexy, 273
Nerve or Nerves —

of abdominal wall, 250

abducent, 207, 225

accessory, 116, 122, 125, 135

alveolar, inferior, 183
resection of, 183
superior, 183

ansa hypoglossi, 154

auricular, great, 108, 174

auriculo- temporal, 174, 183

axillary, 39
injury of, 101

of Bell. See N., thoracic, long

buccinator, 174, 183

chorda tympani, 148

circumflex. SeeN., axillary

crural, anterior. See N., femoral

550

INDEX

Nerve or Nerves (contd.) —

cutaneous, lateral, 399

injury of, 501

medial, of forearm, 38
injury of, 399

posterior, of thigh, 418

of thigh, 418
of deep sensibility, 97
descendens hypoglossi, 116
dorsalis penis, 387

scapula?, 12, 130

injury of, 97

of epicritic sensibility, 97
facial, 177, 213

bruising of, 178, 217

distribution of, 178

injury of, 216

paralysis of, 214
femoral, 406

injury of, 499
gluteal, inferior, 415

superior, 417
hypoglossal, 115, 123, 145

exposure of, 179
ilio-inguinal, 400
infra-orbital, 172
intercosto-brachial, 32
interosseous, dorsal, 73
injury of, 101

volar, 73
lacrimal, 172
laryngeal, external, 161, 168

internal, 159

recurrent. See N., recurrent

superior, 159
lingual, 148, 154, 183

resection of, 183
of lower limb, 499
lumbo-inguinal, 399
mandibular, 182, 234

injection into, 183
maxillary, 233

injection into, 233

inferior. See N., mandibular
median, 37, 72

in hand, 86

injury of, 104, 105
mental, 174
musculo-cutaneous, 37, 42

injury of, 102

of leg. See N., peroneal, super-
ficial

musculo- spiral. See N., radial
to mylo-hyoid, 144, 183
naso-ciliary, 172
obturator, 400, 411

Nerve or Nerves (contd.) —
obturator (contd.) —

injury of, 501
occipital, greater, 138

lesser, 108

oculo-motor, 207, 225
olfactory, 194
ophthalmic, 225, 233
optic, 209

perineal, superficial, 377
peroneal, common, 446, 469
injury of, 500

deep, 472

superficial, 472
of pharyngeal plexus, 190
phrenic, 112, 115, 312
plantar, lateral, 491

medial, 491

popliteal, external. See N.,
peroneal, common

internal. See N., tibial
of protopathic sensibility, 97
pudendal, 374
radial, 38, 39

compression of, 41

exposure of, 41

injury of, 101

superficial branch of, 71
injury of, 101

surface marking of, 40

termination of, 41
ramus communicans, grey, 125

white, 125
recurrent, 162, 168

left, 516
to rhomboids. See N., dorsalis

scapulas
roots, 526
saphenous, 406
of scalp, 219
sciatic, 418, 441

injury of, 499

small. See N., cutaneous,

posterior, of thigh
spermatic, external, 257
spinal, 526

rami of, 526
of stomach, 298
subscapular, lower, 35
superficial, of arm, 45

of face, 172

of forearm, 45

of neck, 108

of palm, 82

of shoulder region, 4

of thigh, 399

INDEX

Nerve or Nerves (contd.) —
supra-orbital, 172
supra-scapular, 127

injury of, 98
supra- trochlear, 172
suralis, 473
sympathetic trunk, 124

injury of, 120
thoracic, long, 131

injury of, 97
thoraco-dorsal, 35
tibial, 445, 476

anterior. See N., peroneal,

superficial
injury of, 500
trigeminal, 233

paralysis of, 204
trochlear, 207, 225
ulnar, 38, 69

dorsal cutaneous branch, 71

in hand, 85

injury of, at elbow, 104

at wrist, 103
vagus, 116
Nervous system, development of,

533

Neural groove, 533
Neuralgia, facial, 183
Nose, 194

development of, 191
meatus, inferior, 194
middle, 194
superior, 194
nerves of, 194
Nuck, canal of, 264

(Edema glottidis, 157
CEsophageal bougie, 511

diver ticulum, 139
(Esophagotomy, 139
(Esophagus, in neck, 139

in thorax, 511
exposure of, 514

malignant disease of, 512
Olecranon, 44

fracture of, 6r, 63

resection of, 65
Olfactory pits, 191
Omental bursa, 280

development of, 303
Omentum, lesser, 279

greater, 279
Orbit, 206

fracture into, 222
Os calcis. See Calcaneus

incisivum, 192, 193

Os trigonum, 489
Otoscopic examination, 211
Ovary, 392
cysts of, 393

Palate, cleft, 192

formation of, 192
Palm, central part of, 84

fascia of, deep, 82
superficial, 81

fascial spaces of, 90

incisions into, 86

muscles of, deep, 89
Palmar aponeurosis, 82

space, middle, 90
incisions into, 90
infection of, 90
Pancreas, 317

blood-supply of, 318, 319

cysts of, 318

development of, 319

ducts of, 318
Pancreatitis, 312, 316
Pan-ophthalmitis, 204
Papilla, duodenal, 315
Paracentesis pericardii, 510

thoracis, 504

tympani, 211
Paracolic gutter, left, 286

right, 285
Paradidymis, 267
Paralysis, Erb-Duchenne, 99

Klumpke, 100
Paraphimosis, 385, 386
Parathyreoid glands, 169
Parietal tuberosity, 218
Parotid gland, 175
abscess of, 177
removal of, 177
tumours of, 177

duct, 176

calculi in, 176
Patella, dislocation of, 467

floating, 442

fracture of, 466
wiring of, 467

ossification of, 452
Pelvis minor, 355

drainage of, 286

fractures of, 355

infection of, 286
Pelvis, female, 387
Penis, 385

blood-supply of, 387

nerve-supply of, 387

root of, 376

552

INDEX

Pericardium, 510
drainage of, 511
effusion in, 510
paracentesis of, 510
surface relations of, 509
Pericolitis, 329
Perineum, 373
female, 396

laceration of, 389
Peritoneal cavity, 277
drainage of, 282
fossae, 307, 330, 341
infra-colic compartment, 283
supra-colic compartment, 282
Peritoneum, 277

pelvic, 357, 3§7
Pes cavus, 491

Petit, triangle of, lumbar, 269
Petro-squamous suture, 212, 215
Phalanges, of hand, 93
necrosis of, 82
ossification, 93
resection of, 93
of toes, 497
Pharyngeal recess, 190
Pharyngotomy, subhyoid, 159
Pharynx, 189
laryngeal, 191
nasal, 189

lymph vessels of, 190
oral, 191
Phimosis, 385
Pia mater, 225
Pisiform bone, 66
Plane, intertubercular, 239
lateral, 239
subcostal, 239
transpyloric, 240
Plantar aponeurosis, 491
Pleura, 505

lines of reflection, 507
surface relations of, 508
Plexus, brachial, 37, 95
cords of, 95

injuries to, 100
exposure of, 127
lesions of, 97, 98
chorioid, 226
coeliac, 312

venous, haemorrhoidal, 370
pampiniform, 257
pterygoid, 225
pudendal, 365
Plica sublingualis, 186
Polydactylism, 95
Pons, 235

Popliteal fossa, 44
Porta hepatis, 310
Portal obstruction, 310
Pott's disease, 518

fracture, 486
Pouch, perineal, deep, 378

superficial, 376
Pre-auricular point, 171
Premaxilla. See Os incisivum
Prepuce, 385
Process, coracoid, 2
fracture of, 13
mastoid, 107, 210
odontoid. See Dens
trochlear, 478
vermiform, 330
abscess of, 333
position of, 331
surgical approach to, 248
Processus vaginalis, 258
Prostate, 364

hypertrophy of, 365

effects of, 366
Prostatectomy, perineal, 379

supra-pubic, 366
Protuberance, occipital, external,

218

Pterion, 229

Pterygo-mandibular raphe, 171
Ptosis, 207
Pylorectomy, 300
Pylorus, 290
recognition of, 294

Quadrilateral space, 39

Radius, fractures of, 68, 69, 77

head of, 45

ossification of, 58
subluxation of, 62

neck, fracture of, 63

ossification of, 58, 77

resection of, 75

styloid process of, 66

surgical approach to, 73
Ranula, 148
Recess, hepato-renal, 283

intersigmoid, 341
Recessus, piriformis, 156

spheno-ethmoidalis, 194
Rectocele, 389
Rectum, 367

anomalies of, 381

blood-supply of, 370

examination of, 372

excision of, 381

INDEX

553

Rectum (contd.) —

lymph vessels of, 372

nerve-supply of, 371

spinal centres for, 529

structure of, 369
Referred pain, 240
Reflex, cremasteric, 269

viscero-motor, 251

viscero-sensory, 242
Region, gluteal, 413

inguinal, 253
Retinacula, peroneal, 471
Retinal haemorrhage, 235
Retropubic pad of fat, 359
Ribs, cervical, 128

nervous symptoms of, 100
removal of, 129

fractures of, 502

resection of, 505
Rickety rosary, 503
Rima glottidis, 157
Ring, femoral, 403

abdominal inguinal, 253

subcutaneous inguinal, 254
Rolando, fissure of. See Sulcus,

central
Roots, nerve, 526

Saphenous opening. See Fossa

ovalis

Soalene tubercle, 130, 132
Scalp, 218

blood-supply of, 218

cysts of, 218

nerves of, 219

skin of, 218

subaponeurotic space of, 219

venous return from, 219

wounds of, 219
Scapula, anastomosis round, 33

excision of, 13

fracture of, 13

ossification of, 12

spine of, 2

winging of, 98
Scarpa, fascia of, 240

triangle of. See Trigone, femoral
Schlatter's disease, 468
Sclera, 208
Scoliosis, 523

Scrotum, development of, 380
Seminal vesicles, 367
Septum femorale, 402
Sheath, axillary, 32, 113

carotid, 114

incisions into, 121

Sheath (contd.)—

carotid, relations of, 115

femoral, 402

palmar, common, 87
incisions into, 88
pus in, 88
Shoulder, congenital elevation of, 24

region, nerves of, 4
referred pain in, 6
tuberculous disease in, 18
Sinus, cavernous, 225

thrombosis of, 208, 225, 235

epididymidis, 265

lateral. See Sinus, transverse

occipital, 225

pocularis. See Utricle, prostatic

sagittal, inferior, 223
superior, 223

straight, 223

transverse, 214, 216, 224

venosus sclerae, 208, 209
Skull, development of, 221

fracture of, 204, 222, 225
Smith's fracture, 77
Snapping hip, 415
Spermatic cord, 255

arterial supply of, 257

coverings of, 255

examination of, 268

exposure of, 254

hydrocele of, encysted, 260
Sphenoidal sinus, 201

empyaema of, 202
Spina bifida, 534
occulta, 534
Spinal medulla, 524

hemi-lesions of, 530

injuries of, 528

membranes of, 526

path of sensory fibres in, 530

structure of, 526

surgical approach to, 532

transverse lesion, complete, 125,

529, 530, 532
Spine, tibial. See Eminence, inter-

condylar
Spleen, 319

enlargement of, 321

lymph vessels of, 321

puncture of, 321
Splenectomy, 321
Stapes, 214, 216
Sternal angle, 502
Stomach, 289

arteries of, 296

development of, 303

554

INDEX

Stomach (contd.) —

examination of, 294, 296
radiographic, 294

fundus of, 289

lymph glands of, 299
vessels of, 298

malignant disease of, 300

nerves of, 298

position of, 290

pylorus of, 290

referred pain, 298

structure of, 294

surgical approach to, 296

ulcer of, 301

perforation of, 283, 286

veins of, 298
Stomodoeum, 191
Strabismus, convergent, 208

divergent, 207
Stye, 203

Sublingual gland, 148, 154
Submaxillary region, 143
inflammation in, 145

duct, 1 86

salivary gland, 144
Subphrenic, area, 283
Sulcus, central, 228

surface marking of, 229

lateral, 229

Supra-hyoid region, 152
Supra-orbital notch, 170
Supra-sternal space, in
Surgical emphysema, 195, 200,

201

Sustentaculum tali, 479, 488, 491
Sylvian point, 229
Sylvius, fissure of. See Sulcus,

lateral
Sympathetic trunk, 124

in thorax, 514, 515
Syndactylism, 95

Talipes, 494

acquired, 494

nerve- anastomosis in, 496
tendon transplantation in,
496

calcaneo-valgus, 494

calcaneo-varus, 494

calcaneus, 494

congenital, 494
tenotomy in, 496

equino-valgus, 494

equino-varus, 495

equinus, 494

valgus, 495

Talipes (contd.)—

varus, 495

Talma- Morison operation, 311
Talus, 480

dislocation of, 486

excision of, 487

ossification of, 489
Tarsal glands, 204
Tarsi, 203
Tarsus, fractures of, 489

ossifi cation of, 489
Teeth, eruption of, 184
Tegmen tympani, 212
Temporal bone, 210

tuberculous disease of, 215
Tendo Achillis. See Tendo cal-
caneus

calcaneus, 474

lengthening of, 475
rupture of, 475
Tenon, capsule of. See Fascia

bulbi

Tentorium cerebelli, 223
Testis, 265

coverings of, 255

descent of, 257

anomalies of, 258, 265

development of, 267

examination of, 268

excision of, 266

gubernaculum, 257

inversion of, 267

lymph vessels of, 257

mediastinum, 266

processus vaginalis, 258

undescended, 265
Thenar eminence, 84

space, 90

incisions into, 90
infection of, 90
Thigh, superficial vessels, 398

surface landmarks, 398
Thoracic duct, 142, 515, 516
Thoracic wall, 502

surface landmarks of, 502
Thumb, dislocation of, 93
reduction of, 95

movements of, 84
Thymectomy, 166
Thymus gland, 166
Thyreo- glossal duct, 169

cysts, 169, 170
Thyreoid gland, 166

adenoma of, 169

blood-supply of, 167

capsule of, 167

INDEX

555

Thyreoid gland (contd.) —
development of, 169
fixation of, 168
isthmus of, 163
lobes of, 167

pyramidal, 167, 169
sheath of, 167
tumours of, 168
Thyreoidectomy, 167
Thyreotomy, 162
Tibia, 468

fractures of, 477
ossification of, 452, 481
surgical approach to, 476
tuberosity, avulsion of, 468
Tic douloureux, 233
Tongue, 185

development of, 193
foramen caecum of, 185
frenulum of, 186
incisions into, 187
lymph vessels of, 186
malignant disease of, 153, 186
removal of lymph glands,

187

removal of, 187
Tonsil, lingual, 185
palatine, 188
blood-supply of, 189
development of, 188
enlargement of, 188
enucleation of, 189
lymph vessels of, 189
malignant disease of, 189
pharyngeal, 190
Torti-collis, 116
Trachea, 163

pressure on, 168
Tracheotomy, high, 164
low, 165
tube, 162

Tract, ilio-tibial, 401
Transpyloric plane, 240
Traube's space, 292
Triangle, deep, of neck, 138
infra-clavicular, superficial, i
lumbar, of Petit, 269
posterior, of neck, 125
exposure of, 126
fascial floor of, 112
muscular floor of, 130
suboccipital, 138
urogenital, 376
Trigone, femoral, 408
Tubal gestation, 392
projection, 190

Tube, auditory, 190, 212
uterine, 391

examination of, 396
fimbrias of, 392
Tubercle, peroneal. See Process,

trochlear

Tuberculum impar, 169
Tubules, seminiferous, 266
Tunica albuginea, 266
vaginalis, 265

hydrocele of, 267
Tympanic antrum, 214
aditus to, 213, 215, 216
pus in, 215

spread of, 215
surgical approach to, 215
Tympanum, 212
inflation of, 190

Ulna, fractures of, 68

head of, 66

ossification of, 58, 77

proximal extremity of, 51
ossification of, 58

styloid process of, 66

surgical approach to, 73
Ulnar paresis, 127
Upper limb, growth of, 65

measurements of, 2
Urachus, 381
Ureter, 353, 354

blood-supply of, 354

calculus in, 362

exposure of, 275

nerve-supply of, 354

pelvic part, 362

position of, 346, 349

referred pain, 354

surgical approach to, 363

transplantation of, 344
Urethra, female, 397

blood-supply of, 397
Urethra, male, 383

cavernous part of, 384

membranous part of, 383

prostatic part of, 383
openings into, 383

rupture of, 378

stricture of, 384
Urogenital diaphragm, 378
Uterus, 390

cervix, 390

development of, 394

ligaments of, 387
position of, 390
Utricle, prostatic, 383

556

INDEX

Uvula vesicaa, 365

Vagina, 388

examination of, 396
Vallecula, 156
Valves, anal, 370
colic (ileo-caecal), 328
rectal, 368
Varicocele, 264

surgical approach, 262
Vas deferens. See Ductus deferens
Vater, ampulla of, 315

surgical approach to, 316
Vein or Veins —

abdominal, superficial, 243

varicosity of, 243
anal, 371
angular, 220
axillary, 34
azygos, 515
basilic, 50

median, 50
cava inferior, 352

obstruction of, 243
cephalic, 6, 34, 50
median, 50
pressure on, 37
cerebellar, 224
cerebral, great, 223, 227
cervical, transverse, 131
cystic, 312

diploic, injury of, 227
dorsal, of penis, deep, 386

superficial, 386
emissary, 219
condyloid, 220
mastoid, 216
parietal, 220

facial, anterior, 118, 147, 175
communications of, 175
common, 117, 161

injury of, 135
posterior, 118
femoral, 408

axial anastomosis of, 408
haemorrhoidal, 370
jugular, anterior, 110, 166
external, 108

resection of, 134
internal, 116, 117, 224
resection of, 117
septic thrombosis of, 213
lingual, 119
median, 50
ophthalmic, 208
pampiniform, 257

Vein or Veins (contd.) —
para-umbilical, 243
portal, 310

anastomoses of, 311
obstruction of, 243
pterygoid plexus, 181, 221
pudendal plexus, 365
pyloric, 294
renal, 352
saphenous, great, 398, 447

varicosity of, 448
small, 447

varicosity of, 448
scapular, transverse, 131
splenic, 321
of stomach, 298
subscapular, 34
superficial, of arm, 50

of forearm, 50
thoraco-epigastric, 243
thyreoid, 168
inferior, 166
middle, 119
superior, 119
vertebral, 141
Ventricular folds, 157
Vertebrae, ossification of, 516
Vertebral column, 516
caries of, 520
curvatures of, 523
angular, 520
backward, 524
forward, 524
lateral, 523
development of, 533
examination of, 522
fracture dislocation of, 529

line of anaesthesia in, 4
injuries of, 528
luxation of articular process, 528

bilateral, 529
movements of, 523
tuberculous disease of, 518
muscular rigidity in, 520
paraplegia in, 522
Verumontanum. See Crest, urethral
Vestibular glands, 397
Visceral arches, 148
clefts, 149

remains of, 150
pouches, 149
Viscero-motor reflex, 298
Viscero-sensory reflex, 328
Vitreous body, 209
Vocal cords, false. See Ventricular
folds

INDEX

557

Vocal cords, true. See Vocal folds

folds, 157

Volkmann's ischaemic contracture,
50

Wharton, duct of.

maxillary

Wolffian duct, 267

See Duct, sub-

Wrist, region of 65

bony landmarks of, 65
tuberculous disease in, 79

Zone of ciliary injection, 208
Zygomatic arch, 170
bone, fracture of, 199

THE END

q$$Zl Bee
B41 A
1916 a

sly, L,
manual of s
natomy

83933

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