BASIC SCIENCE FOR THE MRCS

42 SECTION ONE ANATOMY

l Posterior relations: l Anterior vagus nerve is closely applied to the
n lower cervical vertebrae surface behind its peritoneal covering.
n prevertebral fascia.
l Posterior vagus nerve is at a little distance from the
l To the left: posterior surface of the oesophagus.
n left common carotid artery
n left inferior thyroid artery Blood supply
n left subclavian artery
n thoracic duct. l In the neck: from the inferior thyroid arteries.
l In the thorax: from branches of the aorta.
l To the right: l In the abdomen: from the left gastric and inferior
n right common carotid artery
n recurrent laryngeal nerves lie on either side in phrenic arteries.
the groove between trachea and oesophagus. l Venous drainage:

Thoracic n cervical part to inferior thyroid veins
n thoracic part to azygos veins
l Oesophagus passes downwards through the supe- n abdominal part to azygos vein (systemic) and
rior and posterior mediastinum.
partly to the left gastric veins (portal).
l Initially passes to the right to reach the midline
opposite T5. Nerve supply

l Then passes downwards, forwards and to the left to l Upper third: parasympathetics via recurrent laryngeal
reach to the oesophageal hiatus in the diaphragm nerve and sympathetic nerves from the middle
at T10. cervical ganglion via the inferior thyroid artery.

l The two vagus nerves form a plexus on the surface l Below the root of the lung, the vagi and sympathetic
of the oesophagus in the posterior mediastinum, the nerves contribute to the oesophageal plexus.
left being anterior and the right posterior.
Microscopic structure
l Anterior relations:
n left common carotid artery The oesophagus consists of:
n trachea l Mucous membrane lined by stratified squamous
n left main bronchus, which constricts it
n pericardium separating it from left atrium and epithelium (occasionally there is gastric mucosa in
the diaphragm. the lower part of the oesophagus).
l Submucosa containing mucus glands.
l Posterior relations: l Muscular layer consisting of inner circular and outer
n thoracic vertebrae longitudinal muscle.
n thoracic duct l In upper third, muscle is striated, producing rapid
n hemiazygos vein contraction and swallowing.
n the descending aorta below. l In the lower two-thirds, it is composed of smooth
muscle exhibiting peristalsis.
l To the left side: l Outer layer of loose areolar tissue.
n left subclavian artery
n aortic arch Clinical points
n left vagus nerve and its recurrent laryngeal
branch l There are three narrow points in the oesophagus at
n thoracic duct which foreign bodies may impact:
n left pleura. n commencement of the oesophagus (17 cm
from the upper incisor teeth)
l To the right side: n point at which it is crossed by left main bron-
n right pleura chus (28 cm from incisor teeth)
n azygos vein. n termination (43 cm from upper incisor teeth).

Abdominal l In the lower oesophagus there is a site of portosys-
temic anastomosis: between the azygos vein (sys-
l Passes through oesophageal opening in the right temic) and the oesophageal tributary of the left
crus of the diaphragm at level T10. gastric vein (portal). Oesophageal varices may arise
at this site in portal hypertension.
l Lies in a groove on the posterior surface of the left
lobe of the liver with the left crus of the diaphragm
behind.

l Covered anteriorly and to left with peritoneum.

The abdomen, pelvis and perineum 2 43

l Left atrial enlargement due to mitral stenosis may l The thickened pyloric sphincter surrounds the
be noted on a barium swallow which shows marked pyloric canal.
backwards displacement of the oesophagus by the
dilated atrium. l Junction of pylorus with duodenum is marked by a
constant prepyloric vein of Mayo which crosses it
Stomach vertically.

l Approximately ‘J’ shaped. Relations
l Two surfaces: anterior and posterior.
l Two curvatures: greater and lesser curve. l Anteriorly: from left to right, the diaphragm, abdom-
l Two orifices: cardia and pylorus. inal wall and left lobe of the liver.
l Initially projects to left, the dome-like gastric fundus
l Posteriorly: separated from diaphragm, aorta, pan-
projecting above the level of the cardia. creas, spleen, left kidney and suprarenal gland,
l In the erect living subject, the vertical part of the ‘J’ transverse mesocolon, and colon by lesser sac of
peritoneum.
shape of the stomach represents the upper two-
thirds of the stomach. Blood supply
l Lesser curve of stomach is vertical in its upper two-
thirds but then turns upwards and to the right where The blood supply (Fig. 2.17) is via:
it becomes the pyloric antrum. l The left gastric artery, which is derived from the
l Junction of body with pyloric antrum marked along
the lesser curve by a notch—the incisura angularis. coeliac axis and runs along the lesser curvature
l Body of stomach lies between cardia and pylorus. of the stomach where it anastomoses with the right
l Pyloric antrum is a narrow area immediately before gastric branch of the hepatic artery.
the pylorus. l The right gastric artery from the hepatic artery.
l Left margin of stomach is the greater curvature. l The right gastroepiploic artery: arises from the
l In the erect subject, this may reach or lie below the gastrodudodenal branch of the hepatic artery and
umbilicus. anastomoses along the greater curve with the left
l Greater curvature then passes upwards to the right gastroepiploic artery.
as the lower margin of the pyloric antrum. l Left gastroepiploic artery arises from splenic artery.
l The lesser omentum is attached to the lesser l The short gastric arteries arise from the splenic
curvature of the stomach. artery.
l The greater omentum is attached to the greater l Venous drainage follows the arteries.
curvature of the stomach. l Venous drainage is into the portal system.
l Stomach has such a rich blood supply that ligation
of three of the four main arteries does not compro-
mise its blood supply.

Common hepatic artery Coeliac trunk
Hepatic artery Left gastric artery

Hepatic portal vein Body of Fundus of stomach
Cystic artery stomach Short gastric arteries

Common bile duct Pyloric part Splenic artery
of stomach Spleen
Gastroduodenal artery Left gastroepiploic artery

Right gastric artery Right gastroepiploic artery

Fig 2.17
The arterial blood supply of the stomach.

44 SECTION ONE ANATOMY

Gastric nodes

Hepatic nodes Splenic hilar nodes

Coeliac nodes
Suprapyloric nodes

Gastroepiploic nodes

Subpyloric nodes

Fig 2.18
The lymphatic drainage of the stomach.

Lymphatic drainage (Fig. 2.18) l Posterior vagus nerve gives off coeliac branch pass-
ing to coeliac axis before sending a gastric branch
l Area of stomach supplied by splenic artery drains to the posterior surface of the stomach.
via lymphatics accompanying that artery to lymph
nodes at the hilum of the spleen, and then to those l Gastric divisions of both anterior and posterior vagi
situated along the upper border of the pancreas and reach the stomach at the cardia and descend along
eventually to the coeliac nodes. the lesser curve between the anterior and posterior
peritoneal attachments of the lesser omentum.
l Cardiac area of the stomach drains along the left
gastric artery to reach the coeliac nodes. l These nerves are referred to as the anterior and
posterior nerves of Latarjet.
l The remainder of the stomach drains as follows:
n via branches of the hepatic artery through nodes l Nerve supply of stomach has become largely of
along the lesser curve to the coeliac nodes historical interest, as operations to divide the
n through nodes along the right gastroepiploic vagus nerve are rarely carried out nowadays
vessels to the subpyloric nodes and then to following the advent of H2 receptor antagonists,
the coeliac nodes. proton pump inhibitors, and the discovery of the
role of Helicobacter pylori in the aetiology of peptic
l Retrograde spread of carcinoma may occur into the ulceration.
hepatic lymph nodes at the porta hepatis—enlarge-
ments of these nodes may cause external compres- Structure of the gastric mucosa (Fig. 2.19)
sion of the bile ducts with obstructive jaundice.
l Surface of gastric mucosa covered by columnar
l Extensive and complex lymphatic drainage of epithelial cells that secrete mucus and alkaline
stomach creates problems in dealing with gastric fluid that protect the epithelium from mechanical
cancer—involvement of nodes around coeliac axis injury and from gastric acid.
may render growth incurable.
l The gastric mucosa can be divided into three areas:
Nerve supply n cardiac gland area via gastro-oesophageal
junction containing principally mucus-
l Anterior and posterior vagus nerves enter the abdo- secreting cells
men through the oesophageal hiatus. n acid-secreting region (oxyntic gland area) con-
taining parietal (oxyntic cells) and chief (zymo-
l Anterior vagus nerve lies close to wall of oesopha- gen) cells
gus but posterior nerve is at a little distance from n pyloric end area constituting the distal 30% of
the wall of the oesophagus. the stomach: contains ‘G’ cells that produce
gastrin together with mucus-secreting cells.
l Anterior vagus gives off hepatic branch and pyloric
branch to the pyloric sphincter.

The abdomen, pelvis and perineum 2 45

Surface Second part
mucous cells
Gastric pit l Descends as a curve around the head of the
pancreas.
Mucous
neck cells l Approximately 7.5 cm long.
l Bile ducts and main pancreatic ducts enter the sec-
Parietal
cells ond part of the duodenum together at the duodenal
papilla on its posteromedial side.
l Point of entry marks junction of foregut and midgut.
l Accessory pancreatic duct of Santorini opens into
the duodenum a little above the papilla.
l The second part of the duodenum is crossed by the
transverse colon and lies anteriorly to the right
kidney and ureter.

Chief (zymogen) Third part
cells
l Approximately 10 cm long.
Fig 2.19 l Runs horizontally to left.
A gastric gland and its cells. l Crosses the IVC, the aorta and third lumbar

l Histological features of the mucosa in the oxyntic vertebra.
gland area are shown in Figure 2.19. l Crossed anteriorly by the root of the mesentery and

Clinical points superior mesenteric vessels.

l An ulcer on the lesser curve of the stomach may Fourth part
erode into either the right or left gastric arteries,
resulting in haematemesis and melaena. l Approximately 2.5 cm long.
l Ascends vertically to end by turning abruptly ante-
l A posterior gastric ulcer or carcinoma may erode the
pancreas, giving rise to pain referred to the back. riorly to the left to continue as the jejunum.
l At the duodenojejunal (DJ) flexure, the small
Duodenum
intestine leaves the posterior abdominal wall and
l ‘C’ shaped. acquires a mesentery.
l Curves round the head of the pancreas and is l At surgery the DJ flexure may be identified by the
presence of the suspensory ligament of Treitz—a
approximately 25 cm (10 inches) long. peritoneal fold descending from the right crus
l Divided into four parts. of the diaphragm to the termination of the
duodenum.
First part
Blood supply of the duodenum
l Approximately 5 cm long.
l Ascends from the pylorus, being directed superiorly, l Superior pancreaticoduodenal artery arising from
the gastroduodenal artery.
posteriorly and to the right.
l First 2–3 cm has a complete investment of visceral l Inferior pancreaticoduodenal artery originating from
the superior mesenteric artery.
peritoneum.
l Relations: l These two arteries lie in the curve between
the duodenum and head of the pancreas, supply-
n anteriorly: liver and gall bladder ing both the duodenum and head of the pancreas.
n posteriorly: portal vein, common bile duct, gas-
Clinical points
troduodenal artery; behind these is the IVC.
l The relationship of the gastroduodenal artery to
the first part of the duodenum is important be-
cause erosion of posterior duodenal ulcers into
the gastroduodenal artery will cause haematem-
esis and melaena.

46 SECTION ONE ANATOMY

Small intestine Large intestine

l Variable in length, averaging some 6 m. The large intestine extends from the ileocaecal junc-
l Upper half is termed the jejunum, the remainder the tion to the anus. It is approximately 1.5 m in length in
average. It is divided into:
ileum, although the distinction between the two is l caecum with the vermiform appendix
not sharply defined. l ascending colon
l Jejunum and ileum lie in free edge of mesentery. l hepatic flexure
l The mesentery of the small intestine is about l transverse colon
15 cm long and attached across the posterior l splenic flexure
abdominal wall. l descending colon
l Commences at DJ flexure to the left of the second l sigmoid colon
lumbar vertebra and passes obliquely downwards to l rectum
the right sacroiliac joint. l anal canal.
l From left to right the root of the mesentery crosses
anterior to the following structures: Caecum

n third part of the duodenum l Dilated blind-ended pouch situated in the right iliac
n aorta fossa.
n IVC
n right psoas major muscle l Usually completely covered by peritoneum.
n right ureter l Ileocaecal valve lies on the left side of the junction
n right gonadal vessels
n right iliacus muscle. between caecum and ascending colon.
l Mesentery contains: l Appendix rises from the posteromedial aspect of the
n the superior mesenteric vessels which enter
caecum about 2.5 cm below the ileocaecal valve.
the mesentery anterior to the third part of the
duodenum Ascending colon
n lymph nodes draining the small intestine
n autonomic nerve fibres. l Extends from the caecum to the undersurface of the
l At surgery the following factors serve to distinguish liver, where at the hepatic flexure it turns left to
the jejunum from the ileum: become the transverse colon.
n the jejunum has a thicker wall due to circular
folds of mucosa (valvulae conniventes or plicae l Covered on anterior and lateral aspects by
circulares) which are larger and more numer- peritoneum.
ous than in the ileum
n the jejunum is of greater diameter than the l Posterior relations include:
ileum n iliacus
n in the mesentery of the jejunum, the arteries n quadratus lumborum
form one or two arcades some distance from n perirenal fascia over lateral aspect of kidney.
the free edge of the mesentery, and long
straight branches from these arcades run to Transverse colon
supply the jejunum. In the ileum, the arterial
supply forms several rows of arcades in the l Passes to the left where it becomes the descending
mesentery, and the final straight arteries to colon at the splenic flexure.
the ileum are shorter and more numerous than
in the jejunum l Attached to the anterior border of the pancreas by
n the mesentery becomes thicker and more fat- the transverse mesocolon.
laden from above downwards
n in general, the jejunum is most likely to be l Relations:
found at or above the level of the umbilicus n superiorly: liver, gall bladder, greater curvature
while the ileum tends to lie below the level of stomach and spleen
of the umbilicus in the hypogastrium and n inferiorly: coils of small intestine
pelvis. n anteriorly: anterior layers of the greater omentum
n posteriorly: right kidney, second part of duodenum,
pancreas, small intestine, and left kidney.

Descending colon

l Passes from splenic flexure to sigmoid colon.
l Peritoneum covers its anterior and lateral surfaces.
l Between the splenic flexure and diaphragm is a fold

of peritoneum, the phrenicocolic ligament.

The abdomen, pelvis and perineum 2 47

l Relations: obstruction of the appendicular lumen is a usual
n posteriorly: left kidney, quadratus lumborum precipitating cause of acute appendicitis, it is there-
and iliacus fore uncommon at the extremes of life.
n anteriorly: coils of small intestine. l A long pelvic appendix may hang down and irritate
the bladder, giving rise to frequency of micturition,
Sigmoid colon simulating cystitis.

l Commences at pelvic brim and extends to recto- Rectum
sigmoid junction.
The rectum is about 12 cm (5 inches) long, commenc-
l Has a mesentery which is occasionally extensive, ing anterior to the third segment of the sacrum and
allowing sigmoid colon to hang down into pelvis. ending about 2.5 cm in front of the coccyx, where it
bends sharply backwards to become the anal canal.
l Root of sigmoid colon crosses the external iliac l Peritoneal coverings:
vessels and left ureter.
n extraperitoneal on its posterior aspect
l The sigmoid loop rests on the bladder in the male n upper third: covered by peritoneum on its front
and is related to the uterus and posterior fornix of
the vagina in the female. and sides
n middle third: covered by peritoneum only on its
Taenia coli
anterior aspect
l Three flattened bands of longitudinal muscle which n lower third: completely extraperitoneal, lying
pass from the caecum to rectosigmoid.
below the pelvic peritoneum.
l Converge at the base of the appendix. l Curved to follow the contour of the sacral hollow.
l The taenia are shorter than the length of the bowel, l Three lateral inflexions projected to the left, right

hence the sacculated appearance of the large bowel. and left again from above downwards.
l There are no taenia coli on the appendix or rectum. l Each inflexion is capped by a valve of Houston.

Appendices epiploicae Relations

l Fat-filled tags scattered over the surface of the l Anteriorly:
colon. n in the male lie the rectovesical pouch, base of
bladder, seminal vesicles and prostate
l Most numerous in the sigmoid colon. n a layer of fascia (of Denonvilliers) lies in front of
l Absent on the appendix, caecum and rectum. the rectum, separating it from the prostate
n in the female lie the rectouterine pouch (of
Appendix Douglas) and posterior wall of the vagina
n the upper two-thirds of the rectum are covered
l Attached to posteromedial aspect of the caecum with peritoneum anteriorly and related to coils
below the ileocaecal valve. of small bowel and the sigmoid colon in the
rectovesical or rectouterine pouch.
l Variable in length but usually 5–10 cm.
l Position is variable: l Posteriorly: sacrum, coccyx, lower sacral nerves,
middle sacral artery.
n 75% lie behind the caecum or colon, i.e. retro-
caecal or retrocolic l Laterally: below peritoneal reflexion lie the levator
ani and coccygeus.
n 20% pelvic
n 5% preileal or retroileal. Blood supply of the large intestine
l Bears a mesentery containing the appendicular
artery, which is a branch of the ileocolic artery. (Fig. 2.20)
l Appendix mesentery descends behind the ileum as l Supplied by branches of both the superior and
a triangular fold containing the appendicular artery
in its free edge. inferior mesenteric artery.
l The branches of the superior mesenteric artery are:
Clinical points
n the ileocolic artery, supplying the caecum and
l Appendicular artery is an end-artery and therefore commencement of the ascending colon
in acute appendicitis, if it thromboses, there is a
consequent rapid development of gangrene with n the right colic artery, supplying the ascending
perforation of the appendix. colon

l The lumen of the appendix is relatively wide in
infancy and often obliterated in the elderly. Since

48 SECTION ONE ANATOMY Marginal artery
Superior mesenteric artery
Middle colic artery Inferior mesenteric artery
Right colic artery Left colic artery
Sigmoid branches
Ileocolic artery
Superior rectal artery

Fig 2.20
The arterial blood supply of the large intestine.

n the middle colic artery, supplying the trans- the level of the anal valves where they anastomose
verse colon. with branches of the inferior rectal artery.
l They are accompanied by tributaries of the superior
l The branches of the inferior mesenteric artery rectal vein draining into the portal system.
supplying the colon are: l The position of these vessels, one on the left
n the left colic artery, supplying the descending and two on the right, explain why haemorrhoids
colon occur at 3, 7 and 11 o’clock when the anal canal
n the sigmoid branches, supplying the sigmoid is viewed with the patient in the lithotomy
colon position.
n superior rectal artery, supplying the rectum.
Lymphatic drainage of the large
l Each branch of the superior and inferior mesenteric intestine
artery anastomoses with its neighbour above
and below, establishing a continuous chain of anas- l Lymphatics drain to small lymph nodes lying near or
tomosis along the length of the colon known as the even on the bowel wall.
marginal artery (of Drummond).
l These drain to further groups lying along the blood
l The superior rectal artery supplies the whole of the vessels.
rectum and upper half of the canal, while the inferior
rectal artery supplies the lower half of the anal l These then drain to nodes near the origins of the
canal. superior and inferior mesenteric arteries.

l The middle rectal artery is small and supplies only l Efferent vessels from these join to drain into the
the muscle coats of the rectum. cisterna chyli.

l When the superior rectal artery reaches the rectum, l Field of lymphatic drainage of each segment of
it first divides into two branches, which run either bowel corresponds more or less to its arterial blood
side of the rectum, then the right branch divides into supply.
two further branches. These branches descend to

The abdomen, pelvis and perineum 2 49

l High ligation of the vessels to the involved seg- the abdominal nodes whereas below this site
ment of bowel with the removal of a wide sur- drainage is to the inguinal nodes. This is clini-
rounding segment of mesocolon and bowel wall cally important as a carcinoma of the rectum
will result in the removal of lymph nodes draining which invades the lower anal canal may metas-
that particular area, e.g. division of the inferior tasise to inguinal lymph nodes.
mesenteric artery and resection of sigmoid meso-
colon would be performed for carcinoma of the Anal sphincters
sigmoid colon.
l The anal canal is surrounded by complex arrange-
Anal canal ment of muscles.

The anal canal is about 4 cm long and passes down- l The internal anal sphincter is composed of smooth
wards and backwards. muscle continuous above with the circular muscle
l Surrounded by a complex arrangement of sphincters of the rectum. It surrounds the upper two-thirds
of the canal and is supplied by sympathetic nerves.
consisting of smooth and striated muscle.
l At the midpoint of the canal there is a series of l The external anal sphincter is composed of striated
muscle, which surrounds the internal anal sphincter
vertical columns in the mucosa (the columns of but extends further distally (Fig. 2.21).
Morgagni).
l At the distal end of the vertical columns are some l The external anal sphincter is divided into three parts:
valve-like folds (the anal valves of Ball). n subcutaneous
l Behind these valves are the anal sinuses into which n superficial, which is attached to the coccyx
open the anal glands. behind and the perineal body in front
l The upper half of the anal canal is lined with colum- n deep, which is continuous with the puborectalis
nar epithelium. part of levator ani.
l The lower half is lined with stratified squamous ep-
ithelium transforming into skin near the anal verge. l The deep part of the external sphincter where it
l The boundaries between these zones are not blends with levator ani together with the internal
clear-cut. anal sphincter is termed the anorectal ring.
l The upper half of the anal canal is derived from en-
doderm; the lower half is derived from ectoderm. l The anorectal ring is palpable with a finger in the
There are some important anatomical facts with anal canal where it forms a ring, immediately
clinical significance resulting from this derivation above which the finger enters the ampulla of the
of the anal canal. They are as follows: rectum.

n The upper half is lined by columnar epithelium l The subcutaneous part of the external anal
and the lower half with stratified squamous sphincter is traversed by a fan-shaped expansion
epithelium; consequently, carcinoma of the of longitudinal muscle fibres of the anal canal.
upper anal canal is adenocarcinoma, while
that of the lower part is a squamous cell l Nerve supply of external sphincter is via the inferior
carcinoma. rectal branch and the pudendal nerve (S2, 3) and the
perineal branch of S4.
n The upper half of the anal canal is supplied by
the autonomic nervous system; the lower part Rectal examination
has somatic innervation from the inferior rectal
nerve. The lower part of the anal canal is sen- The following structures can be palpated by the finger
sitive to pinprick sensation, while the upper passed per rectum in the normal patient:
part is not. This is an important factor when l Both sexes:
injecting haemorrhoids.
n anorectal ring
n The upper half of the anal canal drains into the n coccyx
portal venous system whereas the lower half n sacrum
drains into the systemic venous system. This n ischiorectal fossae
therefore is an important site of portosystemic n ischial spines.
anastomosis in portal hypertension. l Male:
n prostate
n The lymphatic drainage of the upper half of the n rarely, the seminal vesicles.
anal canal is along the superior rectal vessels to l Female:
n perineal body
n cervix
n occasionally, the ovaries.

50 SECTION ONE ANATOMY Circular muscle coat of
the rectum
Rectum

External anal Deep Levator ani
sphincter Superficial
Subcutaneous Internal anal
sphincter

Fig 2.21
The anal sphincters.

The following abnormalities can also be detected: l Posteroinferior surface is related to the abdominal
l Lumen: oesophagus, stomach, duodenum, hepatic flexure
of the colon, right kidney and right suprarenal
n faecal impaction gland.
n foreign bodies.
l In the wall: l The posteroinferior surface is covered with perito-
n rectal tumours neum except where the gall bladder is attached
n rectal strictures and at the porta hepatis and the fissure for the liga-
n thrombosed haemorrhoids (haemorrhoids are mentum venosum.

not palpable unless thrombosed). l The posterior surface is connected to the diaphragm
l Outside rectal wall: over the right lobe of the liver by the coronary lig-
ament between the two layers of which is a non-
n prostatic abnormalities peritonealised area, i.e. the bare area.
n abnormalities of the uterine cervix
n ovarian enlargement l To the left of the bare area is the caudate lobe,
n masses in the pouch of Douglas which bounds the lesser sac in front.
n tenderness in the pouch of Douglas with
l The anatomical right and left lobes of the liver
peritonitis are separated anteriorly and superiorly by the
n pelvic bony tumours falciform ligament, and posteroinferiorly by
n foreign bodies in the vagina, e.g. tampon, pes- the H-shaped arrangement of the fossae
(Fig. 2.22).
sary or others.
Porta hepatis
Liver
l Gateway to and from the liver.
The liver is the largest organ in the body. It lies across l Contains the following structures:
the right hypochondrium, epigastrium and left hypo-
chondrium. It is divided into two unequal lobes by a n common hepatic duct anteriorly
fold of peritoneum, the falciform ligament. It has the n hepatic artery in the middle
following features: n portal vein posteriorly.
l Superior surface: dome-shaped; related to the dia- l Contains lymph nodes which when enlarged by ma-
lignancy may compress the bile ducts and cause
phragm which separates it from the pleura, lungs, obstructive jaundice
pericardium and heart.

The abdomen, pelvis and perineum 2 51

Fissure for the
ligamentum venosum

IVC

Caudate lobe

Gastric Renal
Duodenal

Porta hepatis

Colic

Ligamentum teres

Gall bladder

Quadrate lobe

Fig 2.22

The inferior aspect of the liver. The H-shape (dotted line) demonstrates the various fissures, the groove for
the IVC and the fossa for the gall bladder. The sites of impressions of the various relations are indicated in italics.

Portal vein Caudate process
Caudate lobe Inferior vena cava

Left triangular ligament Superior layer of
coronary ligament (cut)
Lesser omentum Left lobe Bare area
(cut) in the Inferior layer of coronary ligament (cut)
fissure for Right Right triangular ligament
lobe
ligamentum venosum Gall bladder

Hepatic artery

Left hepatic duct

Quadrate lobe

Porta hepatis Common bile duct
Common hepatic duct

Fig 2.23
The liver—posterior view.

Peritoneal relations of the liver (Fig. 2.23) l Upper and lower leaves of coronary ligament fuse to
form the right triangular ligament.
l The liver is almost completely covered by peritoneum,
except for the bare area in which the IVC is embedded. l Falciform ligament passes upwards from umbilicus
to right of midline, the ligamentum teres running in
l Bare area is between upper and lower leaves of its free border.
coronary ligament.

52 SECTION ONE ANATOMY

l Falciform ligament passes over dome of liver and VIII II
separates, its right part joining the upper leaf of IV III
the coronary ligament, while the left part forms part V
of the left triangular ligament, the latter being A Falciform ligament
attached to the peritoneum on the undersurface Gall bladder
of the diaphragm.
VIII II
l The left triangular ligament when traced to the right VII IV III
and posteriorly joins the lesser omentum in the
fissure for the ligamentum venosum. V Falciform ligament
Gall bladder
l The left triangular ligament contains no major blood VI
vessels and therefore may be divided safely so that B Gall bladder
the left lobe of the liver may be retracted to expose Falciform ligament
the oesophagus.
V IV
l The lesser omentum arises from the fissure for the VI III
ligamentum venosum and porta hepatis and passes
as a sheet to be attached along the lesser curve of VII II
the stomach. I

l The free edge of the lesser omentum contains the C IVC
common bile duct to the right, the hepatic artery
to the left and the portal vein posteriorly. Fig 2.24

Functional anatomy of the liver The functional division of the liver into segments:
A anterior view, as seen in the patient, B anterior
l The gross anatomical division of liver into right and view with the liver ‘flattened’ in the ex-vivo
left lobes demarcated by falciform ligament anteriorly position (note that segments VI and VII may now
and fissure for ligamentum teres and ligamentum be seen—in vivo they appear more laterally and
venosum posteroinferiorly is not pertinent to under- posteriorly), C inferior view.
standing of the surgical anatomy of the liver.
l They pass backwards and upwards from the sub-
l Functional anatomy is based on the description of stance of the liver, draining into the IVC at the
hepatic segmentation which divides the liver into superior limit of the liver.
segments according to the distribution of portal
pedicles and location of hepatic veins. l The caudate lobe of the liver has independent
hepatic veins which drain directly into the IVC.
l Functional division of liver into right and left lobes is
not demarcated by any visible line on the surface of l Three main hepatic veins divide the liver into four
the liver. sectors, each of which receives a portal pedicle,
with an alternation between hepatic veins and
l The division is through a plane which passes portal pedicles (Fig. 2.25).
through the gall bladder fossa and fossa for the IVC.
l Middle hepatic vein lies at the line of the principal
l Each of these two functional lobes has its own plane of the liver between its right and left func-
arterial and portal venous blood supply and its tional lobes.
own biliary drainage.
l Terminology in liver resection is based on function
l Surgical division of the right hepatic artery and right and segmental anatomy.
branch of the portal vein is followed by a clear de-
marcation on the liver surface running anteropos- l A right hemihepatectomy would involve segments
terior from the gall bladder fossa to the IVC in the V, VI, VII and VIII.
principal vascular plane.
l A left hemihepatectomy would involve segments II,
l These two functional lobes are further subdivided III and IV.
into segments, each lobe being divided into four
segments (Fig. 2.24).

Hepatic veins

l Three main hepatic veins:
n right
n central
n left.

The abdomen, pelvis and perineum 2 53

IVC

Right hepatic vein Middle hepatic vein
Left hepatic vein

I

VII VIII IV III II

VI
V

Portal vein

Fig 2.25

A schematic representation of the functional anatomy of the liver. The three main hepatic veins divide
the liver into four sectors, each of which receives a portal pedicle.

l Excision of the anatomical left lobe of the liver l The opening of the ampulla of Vater into the duode-
would involve only segments II and III. num is guarded by the sphincter of Oddi (periampul-
lary sphincter).
l Excision of the functional left lobe of the liver would
involve segments II, III, IV and possibly I. l Occasionally bile duct and pancreatic ducts open
separately into the duodenum.
Extrahepatic biliary system (Fig 2.26)
l There may be an additional duct, which receives
Right and left hepatic ducts join at porta hepatis to ducts from the lower part of the head of the pan-
form common hepatic duct. creas, known as the accessory pancreatic duct. It
l Common hepatic duct is joined by cystic duct to opens into the medial wall of the second part of
the duodenum about 2 cm proximal to the main
form bile duct (common bile duct). duodenal papilla (endoscopists should be aware
l Bile duct is about 9 cm long commencing approxi- of these anatomical variations).

mately 4 cm above the duodenum then passing l The common hepatic duct and supraduodenal part
behind it. of the common bile duct lie in the free edge of the
l Bile duct runs in a groove on the posterior aspect of lesser omentum. Their relations are as follows:
the head of the pancreas before opening into the n bile duct: anteriorly to the right
medial aspect of the second part of the duodenum. n hepatic artery: anteriorly to the left
l In 90% of individuals, the main pancreatic duct joins n portal vein: posterior
the common bile duct to form a common dilated n IVC, posteriorly: separated from the portal vein
channel, i.e. the ampulla of Vater. by the epiploic foramen.

54 SECTION ONE ANATOMY

Right hepatic duct Left hepatic duct
Cystic duct Common hepatic duct
Gall bladder Common bile duct
Pancreatic duct
Duodenum (2nd part)

Fig 2.26
Magnetic resonance cholangiopancreatogram (MRCP).

Gall bladder l Occasionally the cystic artery arises from the main
hepatic artery and crosses in front of or behind the
l Pear-shaped organ adherent to the undersurface (common) bile duct or common hepatic duct.
of the liver, lying in a fossa which separates the
morphological right and left lobes. l Gall bladder also obtains a blood supply directly
from arteries in the bed of the liver.
l Acts as a reservoir for bile, which it also
concentrates. l Venous drainage is via small veins draining directly
into the bed of the liver.
l Holds about 50 mL of bile when physiologically
distended. Clinical points

l The gall bladder consists of: l Variations in the anatomy of the extrahepatic biliary
n fundus system are not uncommon (Fig. 2.28).
n body
n neck: the neck opens into the cystic duct which l The close relationship between the fundus of the gall
conveys bile to and from the common bile duct. bladder and duodenum may result in inflamed gall
bladder ulcerating into the duodenum, causing
l The lumen of the cystic duct contains a spiral a cholecystoduodenal fistula and subsequent gall-
mucosal valve (of Heister). stone ‘ileus’.

l The gall bladder is related inferiorly to the duode- l Haemorrhage during cholecystectomy or from liver
num and transverse colon. trauma may be controlled by compressing the
hepatic artery and portal vein in the free edge
l A small pouch may be present on the ventral aspect of of the lesser omentum (Pringle’s manoeuvre).
the gall bladder just proximal to the neck (Hartmann’s
pouch); a stone may lodge in the pouch. l Gangrene of the gall bladder is rare because even if
the cystic artery thromboses, it gets a second blood
Blood supply (Fig. 2.27) supply directly from the liver bed.

l Via the cystic artery (usually a branch of the right l The wall of the gall bladder and cystic duct contains
hepatic artery). smooth muscle. This is virtually absent in the bile
duct, hence little pain from a gallstone in the
l Cystic artery lies in a triangle made up of the liver, bile duct.
the cystic duct and the common hepatic duct, i.e.
Calot’s triangle. l The mucosa is lined throughout by columnar cells
and bears a considerable number of mucus-
l Cystic artery passes behind the common hepatic producing goblet cells.
duct and cystic duct to gain the upper surface of
the neck of the gall bladder.

Right hepatic The abdomen, pelvis and perineum 2 55
artery
Left hepatic
Cystic artery artery

Gall bladder Common
hepatic artery

Cystic duct Common bile Fig 2.27
duct The gall bladder and its arterial supply.

A BC D

Fig 2.28

Variations in the extrahepatic biliary anatomy. A A long cystic duct joins the common hepatic duct behind
the duodenum. B The cystic duct is short or absent, the gall bladder opening directly into the common
hepatic duct. C The cystic duct enters the right hepatic duct. D Accessory hepatic ducts may open into
the gall bladder or cystic duct.

l When the neck of the gall bladder is obstructed, bile l Portal vein is formed by the junction of the splenic
is absorbed and the goblet cells produce mucus, vein and superior mesenteric vein behind the neck
resulting in a mucocele of the gall bladder. of the pancreas.

The portal venous system (Fig. 2.29) l Inferior mesenteric vein ascends above the point of
origin of its artery to enter the splenic vein behind
l A portal system is one that has capillaries at each the body of the pancreas.
end.
l Portal vein ascends behind first part of duodenum,
l The portal venous system drains blood from: entering the free edge of the lesser omentum in the
n the abdominal part of the alimentary canal anterior wall of the foramen of Winslow.
(excluding the lower part of the anus)
n spleen l At this point it lies immediately posterior to bile duct
n pancreas and hepatic artery.
n gall bladder.
l Portal vein ascends to porta hepatis where it divides
into right and left hepatic branches, breaking up into
capillaries running between the lobules of the liver.

56 SECTION ONE ANATOMY

IVC
Hepatic veins
draining into IVC

Portal vein

Splenic vein

Inferior mesenteric Fig 2.29
vein The portal venous system.

Superior mesenteric
vein

l These capillaries drain into the radicles of the Clinical points
hepatic vein, eventually emptying into the IVC.
l Surgery on patients with portal hypertension may be
l There are no valves in the portal system so that ob- very complicated and very bloody. This is due to di-
struction, e.g. due to cirrhosis of the liver, causes a lated veins in the abdominal wall, in the mesentery
rise in pressure throughout the system. and in the retroperitoneal area. Pressure in these
veins may be extremely high, resulting in consider-
l In order to escape, the blood passes through any able portal venous bleeding.
anastomosis between portal and systemic system
and the anastomotic veins become dilated and Pancreas
may bleed.
The pancreas lies retroperitoneally in the upper abdo-
l Sites of anastomosis between portal and systemic men in the transpyloric plane. It is divided into:
venous system are: l head
n between the oesophageal branch of the left l uncinate process
gastric vein (portal) and the oesophageal tribu- l neck
taries of the azygos system (systemic); in the l body
presence of portal hypertension oesophageal l tail.
varices will develop that may be the source The head of the pancreas lies in the C-shape of the
of severe haematemesis duodenum and is continuous with the uncinate pro-
n between the superior rectal branch of the inferior cess below, which passes posterior to the superior
mesenteric vein (portal) and the inferior rectal mesenteric vessels as they in turn pass from behind
veins (systemic); this may give rise to dilated the head of the pancreas and into the root of the
veins in the anal canal which bleed mesentery (Fig. 2.30).
n between the portal tributaries in the mesentery
and retroperitoneal veins (systemic), resulting Relations
in retroperitoneal varices
n between the portal veins in the liver and the l The head of the pancreas is adherent to the medial
veins of the abdominal wall (systemic) via veins aspect of the C-shaped portion of the duodenum
passing along the falciform ligament to the and lies in front of the IVC, renal vessels and
umbilicus; this may result in the formation of a superior mesenteric vessels.
group of dilated veins radiating out from the
umbilicus known as a caput medusae l The uncinate process lies behind the superior
n between portal branches in the liver and the mesenteric vessels.
veins of the diaphragm (systemic) in relation
to the bare area of the liver. l The common bile duct passes through a groove on
the posterior aspect of the head of the pancreas.

Common bile duct The abdomen, pelvis and perineum 2 57

Accessory pancreatic duct Main pancreatic duct (of Wirsung)
(of Santorini)

Duodenal papilla

Superior mesenteric artery and vein

Fig 2.30
The pancreas and duodenum, showing the common bile duct and pancreatic ducts with their orifices.

l The stomach and first part of the duodenum lie l Lobules composed of acini of serous cells, which
partly in front of the head of the pancreas, separated secrete pancreatic enzymes.
from it by the lesser sac.
l Ducts lined by cuboidal epithelium drain secretions
l Behind the neck of the pancreas lies the junction of into pancreatic ducts.
the superior mesenteric vein and splenic vein, form-
ing the portal vein. l Scattered throughout the pancreas are the islets of
Langerhans, which appear as spheroidal clusters of
l The body of the pancreas is in contact posteriorly pale-staining cells with a rich blood supply.
with the aorta, the left crus of the diaphragm, and
the suprarenal gland and left kidney. l Cells of islets of Langerhans secrete insulin and
glucagon.
l The tail of the pancreas lies at the splenic hilum.
l The tortuous splenic artery runs along the superior Blood supply

border of the pancreas. l From splenic artery via arteria pancreatica magna.
l The splenic vein runs behind the pancreas. l Supply to head and uncinate process is from supe-
l The transverse mesocolon is attached along the
rior pancreaticoduodenal artery, which is a branch
anterior aspect of the pancreas. of the gastroduodenal artery, and the inferior pan-
l Below the attachment of the transverse mesocolon, creaticoduodenal artery, which is a branch of the
superior mesenteric artery.
the duodenal-jejunal flexure, the left flexure of the
colon, the small intestine, lie in relation to the gland. Lymphatics
l The main pancreatic duct (of Wirsung) passes along
the gland from the tail to the head, joining the com- l These drain into:
mon bile duct before entering the medial aspect of n nodes along the upper border of the pancreas
the second part of the duodenum at the ampulla of n nodes related to the medial aspect of the duo-
Vater. denum and head of the pancreas
l The accessory duct (of Santorini) passes from the n nodes in the root of the mesentery.
lower part of the head in front of the main duct, usu-
ally communicating with it, and if present, opens Spleen
into the duodenum approximately 2 cm proximal
to the ampulla of Vater. l About the size of the patient’s clenched fist.
l Lies in the left hypochondrium.
Structure l Forms the left lateral extremity of the lesser sac.
l The gastrosplenic ligament connects it to the
l Gland encapsulated by fibrous capsule sending
septae into the gland, forming lobules. greater curvature of the stomach (carries the short
gastric and left gastroepiploic vessels).

58 SECTION ONE ANATOMY

l The lienorenal ligament connects it to the posterior Relations (Figs 2.31 and 2.32)
abdominal wall (carries the tail of the pancreas and
the splenic vessels). l At the medial aspect of the kidney there is a vertical
slit, the hilum, which transmits from before back-
Relations wards the renal vein, the renal artery and the pelvis
of the ureter.
l Anteriorly: the stomach.
l Posteriorly: the left part of the diaphragm separating l Lymphatics and nerves also enter at the hilum.
l The kidney lies in a fatty cushion (perinephric fat)
it from the pleura, left lung, and 9th, 10th and 11th
ribs. contained within the renal fascia.
l Inferiorly: the splenic flexure of the colon. l Above, the renal fascia blends with the fascia over
l Medially: the left kidney.
the diaphragm, leaving a separate compartment for
Blood supply the suprarenal gland (it is therefore easily separated
from the kidney and left behind during a
l Via the splenic artery which is a branch of the nephrectomy).
coeliac axis. l Medially, the fascia blends with the sheaths of the
aorta and IVC.
l The splenic vein is joined by the superior mesenteric l Laterally, it is continuous with transversalis fascia.
vein to form the portal vein. l It remains open inferiorly.
l The kidney has three capsules:
l The splenic artery and vein, lymph nodes and the
tail of the pancreas are enclosed in the lienorenal n fascial (renal fascia)
ligament. n fatty (perinephric fat)
n a true fibrous capsule, which strips readily from
Clinical points
the kidney surface.
l Trauma to the left lower chest wall and left upper
abdomen may result in damage to the spleen; look Blood supply
particularly for fractures of the left lower ribs.
l From the renal artery directly from the aorta.
l Accessory spleens (splenunculi) occur near the l The renal vein drains into the IVC.
hilum, tail of the pancreas, omentum, small bowel l The left renal vein which is longer than the right and
mesentery; if left behind they may hypertrophy and
result in persistence of symptoms following sple- receives two tributaries, the adrenal and gonadal
nectomy, e.g. for thrombocytopaenic purpura. vein, passes in front of the aorta immediately below
the origin of the superior mesenteric artery.
Kidneys l The right renal artery passes behind the IVC.
l Aberrant vessels are common.
l The kidneys lie retroperitoneally on the posterior
abdominal wall. The right kidney lies lower than Lymphatic drainage
the left, due to downward displacement by the liver.
l Lymph drains directly to the para-aortic lymph
nodes.

Area for suprarenal glands Gastric area
Duodenal area Splenic area
Hepatic area

Aorta

Pancreatic
area

Colic
area

Colic area Jejunal area Fig 2.31

Left renal vein The anterior surfaces of the kidneys and
Inferior vena cava their relations.

Areas for diaphragm The abdomen, pelvis and perineum 2 59

Suprarenal Areas for
glands transversus
abdominis
Areas for
quadratus
lumborum

Areas for psoas major Fig 2.32
The posterior relations of the kidneys.

Clinical points l The ureter is a hollow muscular tube which com-
mences at the renal pelvis and terminates at
l Hypermobility of the kidney may occur (floating kid- its entry into the bladder.
ney): the kidney can be moved up and down in its
fascial compartment, but not from side to side. l The upper end of each ureter is expanded at the pelvis,
which is divided into two parts called major calyces.
l Blood from a traumatic rupture of the kidney or These are subdivided into about 12 minor calyces.
pus in a perinephric abscess will distend the renal
fascia and then take the line of least resistance, l Papillae project into the calyces, the latter being the
tracking down within the fascial compartment to apices of the renal pyramids.
the pelvis.
l The ureter is divided into three parts:
l Anatomy of surgical exposure of the kidney via a n abdominal
loin approach: n pelvic
n an oblique incision is made halfway between n intravesical.
the 12th rib and iliac crest, extending forwards
from the lateral border of erector spinae to the l Relations of the ureter in the abdomen:
lateral border of rectus abdominis n anterior: peritoneum, colic vessels, testicular or
n latissimus dorsi and serratus posterior inferior ovarian vessels, ileum and mesentery (right
are divided side), sigmoid colon and sigmoid mesocolon
n the free posterior border of external oblique is (left side)
identified and split along the line of its fibres n posteriorly: psoas major, psoas minor tendon
n internal oblique and transversus are then (occasionally), genitofemoral nerve and bifur-
divided, revealing peritoneum anteriorly cation of common iliac artery
n the peritoneum is swept forwards n the right ureter lies close to the lateral side of
n the renal fascial capsule is opened the IVC.
n the subcostal nerve and vessels are usually
encountered and are preserved l Relations in the pelvis:
n if more room is required, the lateral edge of n In the male:
quadratus lumborum is divided and part of l each ureter enters the pelvis by crossing the
the 12th rib excised, being careful not to bifurcation of the common iliac artery; runs
damage the pleura which descends below down to ischial spine, crossing the obturator
the medial half of the rib. nerve and the anterior branches of the inter-
nal iliac artery; turns medial to reach the
Ureter bladder and passes below the vas deferens
just before entering the bladder.
l Conveys urine from kidneys to bladder. n In the female:
l Each ureter is 25–30 cm long and approximately l course as above for male, but ureter crosses
close to the lateral fornix of the vagina below
3 mm in diameter. the uterine artery and posterior part of blad-
der, and ends as in male.

60 SECTION ONE ANATOMY

l Narrowest parts of ureter are: l Cortex derived from mesoderm.
n pelviureteric junction l Medulla receives preganglionic sympathetic fibres
n at the brim of the pelvis
n at entry to bladder. from the greater splanchnic nerve and secretes
adrenaline and noradrenaline.
l Calculus may impact at one of these three areas. l The cortex secretes mineralocorticoids (from zona
glomerulosa), glucocorticoids (from zona fascicu-
Blood supply lata) and sex hormones (from the zona reticularis).

l The ureter receives a rich segmental blood supply Bladder
from:
n renal arteries (may receive a considerable con- The bladder is a distensible reservoir with muscular
tribution from a lower polar artery) walls. It lies in the true pelvis posterior to the symphy-
n testicular or ovarian artery sis pubis. It does not rise above the pubis until it is very
n internal iliac artery full. When fully distended, the adult bladder projects
n inferior vesical arteries. from the pelvic cavity into the abdomen, lifting the
peritoneum upwards from the abdominal wall as it
Clinical points distends.

l Ureter readily identified at operation as it strips up Relations
with the peritoneum and worm-like movements can
be noticed in its wall, particularly if it is stimulated l Anteriorly: the pubic symphysis.
by the tip of a pair of forceps. l Superiorly: covered by peritoneum with coils of

l A ureteric stone on a plain radiograph may be seen small intestine and sigmoid colon resting on it.
along the course of the ureter projected onto the The relationship between the sigmoid colon and
bony skeleton: bladder is important in diverticular disease when
n runs along the tips of the transverse processes a colovesical fistula may arise. In the female the
n crosses in front of the sacroiliac joint body of the uterus lies superior to the bladder.
n swings out on the pelvic wall and crosses the l Posteriorly: in the male, the rectum and seminal
ischial spine vesicles; in the female, the vagina and supravaginal
n passes medially to bladder. part of the cervix.
l Laterally: the bladder is separated from levator ani
Suprarenal glands and obturator internus muscle by loose connective
tissue.
l Asymmetrical. l The neck of the bladder fuses with the prostate in
l Right is pyramidal and embraces the upper pole of the male.
l In the female it lies directly on the pelvic fascia
the right kidney. surrounding the short urethra.
l Left is crescentic and embraces the medial border
Blood supply
of the left kidney above the hilum.
l Superior and inferior vesical arteries which are
Relations branches of the anterior division of the internal iliac
artery.
l Anteriorly: right side—liver, IVC; left side—stomach
across the lesser sac. l Rich venous plexus around the bladder draining into
the internal iliac veins.
l Posteriorly: the diaphragm.
l Inferiorly: the upper pole of the kidney. Lymphatic drainage

Blood supply l Drainage along the vesical vessels to the internal
iliac nodes and then to the para-aortic nodes.
l A branch from the aorta.
l A branch from the inferior phrenic artery. Nerve supply
l A branch from the renal artery.
l Venous drainage on the right is via a short vein l Efferent parasympathetic fibres from S2, 3, 4
accompany the vesical arteries to the bladder and
directly into the IVC. carry motor fibres to muscles of bladder wall and
l Venous drainage on the left is by a longer vein into inhibitory fibres to internal sphincter.

the left renal vein.

Structure

l Comprises a cortex and a medulla.
l Medulla derived from neural crest (ectoderm).

The abdomen, pelvis and perineum 2 61

l Sympathetic efferent fibres carry inhibitory fibres to Normally there are two prostatic capsules but with
bladder muscles and motor fibres to its sphincter. benign prostatic hypertrophy, a third develops:
l True capsule: a thin, fibrous sheath surrounding the
l The external sphincter is made up of striated
muscle supplied by the pudendal nerve. prostate.
l The false capsule: condensed extraperitoneal fascia
l Sensory fibres, stimulated by distension, are con-
veyed in both sympathetic and parasympathetic continuous with the fascia surrounding the bladder
nerves. and with the fascia of Denonvilliers posteriorly—the
prostatic venous plexus lies between the true and
Cystoscopy false capsules.
l Pathological capsule: benign prostatic hypertrophy
l Inspection of the interior of the bladder and three compresses the normal peripheral part of the gland,
orifices, i.e. the internal meatus and both ureters. creating a capsule.
l In enucleation of the prostate for benign prostatic
l Submucosa and mucosa of most of bladder are only hypertrophy, it is the plane between the adenoma-
loosely adherent to underlying muscles, and are tous mass and the pathological capsule that is
thrown into folds when bladder is empty. entered.

l Over the trigone, the mucosa is adherent and Blood supply
remains smooth even in the empty bladder.
l Via the inferior vesical artery which is a branch of
l Between the ureters there is a raised fold of mucosa the internal iliac artery.
called the interureteric ridge.
l Venous drainage is via the prostatic venous plexus
Prostate which drains into the internal iliac vein on each side.

The prostate surrounds the prostatic uretha. There are l Some venous blood drains posteriorly around the
two principal components to the prostate: rectum to the valveless vertebral veins of Bat-
l Glandular component. son—this may explain why prostatic carcinoma
l Smooth muscle component. metastasises early to the bones of the lumbar spine
Approximately 25% of the normal prostate is com- and pelvis.
posed of smooth muscle. The majority of the prostate
lies on the lateral and posterior aspect of the urethra Seminal vesicles
with little anterior prostatic tissue.
l Lie one on each side in the interval between the
Relations base of the bladder anteriorly and the rectum
posteriorly.
l Anteriorly: the pubic symphysis separated by the
extraperitoneal fat of the retropubic space (cave l Lie lateral to the termination of vas deferens.
of Retzius). l Each seminal vesicle has a common drainage

l Posteriorly: the rectum separated by the fascia of with its neighbouring vas via the common ejacu-
Denonvilliers. latory duct.
l The normal vesicles are usually impalpable on rec-
l Superiorly: the prostate is continuous with the neck tal examination; however, if they are enlarged by
of the bladder. infection, e.g. tuberculosis, they become palpable.

l Inferiorly: the apex of the prostate rests on the Uterus (Fig 2.33)
external urethral sphincter within the deep perineal
pouch. The uterus is a pear-shaped organ, which is approx-
imately 7 cm long, 5 cm from side to side at its
l Laterally: levator ani. widest point and 3 cm anteroposteriorly. It is com-
Clinically, the prostate is divided into lobes: posed of:
l The posterior lobe lies posterior to the urethra and l fundus
l body
inferior to the plane defined by the course of the l cervix.
ejaculatory ducts. The fallopian tubes enter into each supralateral angle,
l A median lobe lies between the ejaculatory ducts which lie above the fundus.
and posterior to the urethra.
l Two lateral lobes (right and left lobes) are separated
by a shallow posterior median groove which can be
felt on rectal examination.
l Anterior to the urethra there is a narrow isthmus
only, consisting of mainly fibromuscular tissue.

62 SECTION ONE ANATOMY Cavity of uterus
Rectouterine pouch
Sacral promontory (of Douglas)

Fundus of uterus Rectum
Uterovesical pouch Cervix of uterus

Bladder Vagina
Pubic symphysis

Fig 2.33
Sagittal MRI through the female pelvis showing the uterus and its relations.

Relations Lymphatic drainage

l Anteriorly: the body of the uterus is related to the Lymphatics from the uterus drain as follows:
uterovesical pouch of peritoneum and lies on either l The fundus:
the superior surface of the bladder or occasionally
on coils of intestine. The part of the cervix lying out- n drains along the ovarian vessels to the para-
side of the vagina is related directly to the bladder, aortic nodes
whereas the infravaginal cervix has the anterior
fornix as an immediate anterior relation. n some drains with lymphatics which pass via the
round ligament to the inguinal nodes
l Posteriorly: lies the rectouterine pouch (of Douglas),
which is directly related to coils of intestine lying in n metastases from the fundus of the uterus
the pouch. therefore may occur in the inguinal nodes.

l Laterally: lies the broad ligament; the ureter lies l Body drains via lymphatics in the broad ligament to
superiorly and lateral to the supravaginal cervix. the iliac lymph nodes.

Blood supply (Fig. 2.34) l The cervix drains in three directions:
n laterally via the broad ligament to the external
l Uterine artery (from the internal iliac artery) runs in iliac nodes
the base of the broad ligament, and about 2 cm lat- n posteriorly in the uterosacral fold to the sacral
eral to the cervix it passes anterior and superior to lymph nodes
the ureter, reaching the uterus at the level of the n posterolaterally along the uterine vessels to the
internal os. internal iliac nodes.

l The uterine artery then ascends in a tortuous man- Fallopian tubes
ner, running up the lateral side of the body of the
uterus before turning laterally and inferiorly to the The fallopian or uterine tubes are 10–12 cm long and
uterine tube (fallopian tube), where it terminates run from the lateral side of the body of the uterus to
by anastomosing with the terminal branches of the pelvic wall, where they end by opening near the
the ovarian artery. ovary. The opening of the fallopian tube is called the
ostium. The broad ligament of the peritoneum is draped
l The uterine artery also gives off a descending over the fallopian tube like a sheet over a washing line.
branch which supplies the cervix and upper vagina. l Each tube comprises the following parts:

l Uterine veins accompany the arteries, draining to n the infundibulum: this is the trumpet-shaped
the internal iliac vein. extremity which opens into the peritoneal cavity

Suspensory ligament of ovary The abdomen, pelvis and perineum 2 63

Anastomoses between uterine
and ovarian arteries

Ligament of ovary

Ovarian artery Ovary
Uterine artery

Vaginal artery
Midline artery

Fig 2.34
The arterial supply of the ovary, uterine tube, uterus and vagina.

at the ostium. Its opening is fimbriated and Broad ligament
overlies the ovary
n the ampulla, which is wide, thin-walled and l A fold of peritoneum which connects the lateral
tortuous margin of the uterus with the side wall of the pelvis.
n the isthmus, which is narrow, straight and The broad ligament contains or attaches to the
thick-walled following structures:
n the intramural part. n the fallopian tube in its free edge
l The fallopian tube: n the round ligament
n is covered by peritoneum except for the intra- n the ovarian ligament
mural part n the uterine vessels and branches of the ovarian
n contains a muscular coat of outer longitudinal vessels
and inner circular fibres n the mesovarium attaching the ovary to its
n is lined by mucosa in the form of columnar- posterior aspect
ciliated cells and lies in longitudinal ridges, n lymphatics.
each of which is thrown into numerous folds
n functions to propel ova along the lumen to the l In the base of the broad ligament, the ureter
uterus, accompanied by muscular contraction, passes forwards to the bladder lateral to and
ciliary action and the production of lubricating then immediately above the lateral fornix of the
fluid. vagina.
l A fertilised ovum may occasionally implant ectopi-
cally in the tube—this gives rise to ectopic preg- Vagina
nancy, which may cause rupture of tube with
intraperitoneal haemorrhage. l A muscular tube approximately 7 cm in length.
l The distal end of the tube is open into the peritoneal l The cervix opens into the anterior wall superiorly,
cavity, providing direct communication between the
peritoneum and the outside, and is therefore a bulging into the vaginal lumen.
potential pathway for infection. l The vagina forms a ring around the cervix and

although this ring is continuous, it is divided into
anterior, posterior and lateral fornices.

64 SECTION ONE ANATOMY

l It surrounds the cervix of the uterus and then passes Relations
downwards and forwards through the pelvic floor to
open into the vestibule (the area enclosed by the la- l Extremely variable in position.
bia minora and containing the urethral orifice lying l Lies on the side wall of the pelvis in a shallow ovar-
immediately behind the clitoris).
ian fossa surrounded by the external iliac vessels in
Relations front and the ureter and internal iliac vessels
behind.
l Anteriorly: cervix enters the vagina above, and be- l Fascia over obturator internus forms the floor of this
low this is the base of the bladder and the urethra fossa and obturator nerve is close by.
which is embedded in the anterior vaginal wall. l Ovary is very variable in position and may prolapse
into the pouch of Douglas.
l Posteriorly: the posterior fornix is covered by perito- l Relations of the ovary are of considerable impor-
neum in the rectouterine pouch (of Douglas). Below tance clinically. They may be divided into:
this the anterior wall of the rectum is immediately pos-
terior to the vagina and below that the anal canal is n structures within the broad ligament
separated from it by the perineal body. n structures on the lateral wall of the pelvis
n abdominal and pelvic viscera.
l Superiorly: the ureter lies superior and lateral to the
lateral fornix. Blood supply

l Laterally: levator ani and pelvic fascia. l From the ovarian artery, which is a branch of the
aorta arising at the level of the renal artery.
Blood supply
l The right ovarian vein drains into the IVC.
l The arterial blood supply is derived from several l The left ovarian vein drains into the left
sources on each side:
n the vaginal artery renal vein.
n the uterine artery
n the middle rectal artery Lymphatic drainage
n the internal pudendal artery supplying the lower
third. l Follows the ovarian arteries to the para-aortic
nodes.
l Venous drainage is via a plexus of veins in the con-
nective tissue around the vagina draining into the Vaginal examination
internal iliac vein.
l Inspection of the introitus while the patient
Lymphatic drainage strains detects uterine prolapse and stress
incontinence.
l From the upper third drains into the internal and
external iliac nodes. l Anteriorly, the urethra, bladder and pubis may
be felt.
l From the lower third drains into the superficial
inguinal nodes. l Posteriorly, the rectum may be felt and the presence
of invasion of the posterior vaginal wall by a rectal
Ovary neoplasm assessed; abnormalities may be felt in
the pouch of Douglas, e.g. ovarian lesions, malig-
l Size and shape of an almond. nant deposits.
l Attached to the posterior aspect of the broad liga-
l Laterally, the ovary, tube and side wall of the pelvis
ment by the mesovarium. may be felt; rarely a stone may be palpated in the
l The superior pole is attached to a prominent ureter via the lateral fornix.

fold of peritoneum, the suspensory ligament of l At the apex, the cervix is felt projecting back from
the ovary, which passes upwards over the pelvic the anterior wall of the vagina. In the normal ante-
brim and external iliac vessels to merge with the verted uterus the anterior lip of the cervix presents
peritoneum over psoas major. first; in retroversion either cervical os or posterior lip
l Ovarian artery gains access to the ovary through the are felt first; cervical neoplasia can be felt.
mesovarium and suspensory ligament.
l A further ligament, the ovarian ligament, runs within l Bimanual examination assesses pelvic size, size of
the broad ligament to the cornu of uterus. uterus, position of uterus, enlargement of ovary,
abnormalities of uterine tube.

OSCE SCENARIOS The abdomen, pelvis and perineum 2 65

OSCE scenario 2.1 OSCE scenario 2.2

A 19-year-old male presents with a history of A 40-year-old male presents with severe pain in
vague central abdominal pain of 8 h duration. He the right loin radiating into the right groin. A diag-
has now developed a sharp pain in the right iliac nosis of right ureteric colic is made and a plain
fossa which is exacerbated by moving and cough- abdominal radiograph is requested.
ing. He has a temperature of 37.4 C and a white 1. Where would you look for the course of the
cell count of 15 Â 109/L. He is tender with re-
bound in the right iliac fossa. A provisional diagno- ureter projected onto the bony skeleton?
sis is made of acute appendicitis and he elects for 2. At which points along the course of the ureter is
an open appendicectomy.
1. Explain the anatomical basis for the two types of a stone likely to impact?
3. How would you identify the ureter during an
pain he has experienced.
2. Describe the structures encountered in a extraperitoneal approach?
4. What is the blood supply of the ureter and why,
gridiron incision for appendicectomy.
3. What variations in position of the appendix may when removing a kidney for transplantation, is it
important to leave abundant connective tissue
be encountered when attempting to locate the around the ureter?
appendix? Answers in Appendix page 450

SECTION ONE ANATOMY

CHAPTER 3

The upper limb and breast

THE PECTORAL GIRDLE l It is the first bone to ossify in the fetus.
l It is the only long bone to develop in membrane.
The pectoral girdle consists of two bones: l It may be pierced by the supraclavicular nerves.
l clavicle l It transmits forces from the upper limb to the axial
l scapula.
These are joined to: skeleton.
l the axial skeleton at the sternoclavicular joint l It acts as a strut to hold the arm free from the
l each other at the acromioclavicular joint.
trunk.
THE BONES OF THE UPPER LIMB l It is the most commonly fractured bone in the body,

Scapula (Fig. 3.1) the fracture usually occurring at the junction of the
middle and outer thirds.
l Extends from 2nd to 7th ribs posteriorly (when arm
is by side). Humerus (Fig. 3.2)

l Spine, acromion and coracoid process are easily l Head is third of a sphere and faces medially,
palpable. upwards and backwards.

l The glenoid fossa laterally contributes to the l Head is separated from the greater and lesser
shoulder joint. tubercles by the anatomical neck.

l Rotation of the scapula is required in full abduction l The tubercles are separated from one another by
of the limb. the bicipital groove (containing the tendon of the
long head of the biceps).
l Strong muscular coverings protect the scapula
and fracture is rare, requiring direct and severe l The upper end and shaft meet at the surgical neck
violence. around which lies the axillary nerve and circumflex
humeral vessels.
Clavicle
l The shaft is circular in section above and flattened
l Medial two-thirds convex anteriorly and circular in lower down.
cross-section.
l The spiral groove lies posteriorly on the shaft
l Lateral third convex posteriorly and flattened in and is related to the radial nerve, which winds
cross-section. round it between the medial and lateral head of
triceps.
l Articulates medially at the sternoclavicular joint
(articular disc in joint). l The lower end bears the rounded capitulum laterally
for articulation with the radial head, and the trochlear
l Attached to first costal cartilage by costoclavicular medially for articulation with the trochlear notch of
ligament. the ulna.

l Articulates laterally with acromion at acromioclavi- l Medial and lateral epicondyles are extracapsular.
cular joint (incomplete articular disc in joint). The ulnar nerve lies in a groove on the posterior
aspect of the medial epicondyle.
l Attached to coracoid process by tough coracoclavi-
cular ligament. l Fractures of the humerus are common and impor-
tant in view of the close relationship of the axillary,
l It has no medullary cavity. radial and ulnar nerves.

66

The upper limb and breast 3 67

Scapular notch Coracoid process Acromion Superior angle
Acromion
Coracoid process
Superior
angle Glenoid Glenoid

Supraspinous cavity cavity
fossa

Spine of
scapula

Infraspinous
fossa

Anterior surface Medial
border

Lateral border

Inferior angle Inferior
angle
A
Fig 3.1 B
The scapula. A Posterior view, B anterior view.

Anatomical neck Head

Greater Lesser
tuberosity tuberosity
(tubercle) (tubercle)

Surgical Bicipital groove
neck (intertubercular
sulcus)

Deltoid Spiral groove
tuberosity for radial
nerve

Shaft Coronoid Lateral
fossa epicondyle
Lateral
supracondylar Medial Trochlea
epicondyle
ridge Olecranon
Trochlea Medial fossa Fig 3.2
Lateral epicondyle
epicondyle The humerus. A Anterior view,
B B posterior view.
Capitulum
Radial
fossa

A

68 SECTION ONE ANATOMY

Radius and ulna (Fig. 3.3) Metacarpals and phalanges

l Considered together as they are complementary in l First metacarpal is important because of the mobil-
the make-up of the forearm. ity of its carpometacarpal joint, which is responsible
for opposition of the thumb.
l Radius consists of head, neck, shaft and expanded
distal end. l Second metacarpal articulates with three carpal
bones: trapezium, trapezoid and capitate.
l Ulna consists of the olecranon, trochlear fossa, cor-
onoid process with its radial notch (for articulation l Capitate articulates with three metacarpals: second,
with the radial head), shaft and small distal head third and fourth.
(for articulation with the medial aspect of the distal
radius). JOINTS OF THE UPPER LIMB

The carpus (Figs 3.4 and 3.7) Shoulder joint (Fig. 3.5)

l Made up of two rows of four bones. l Ball-and-socket joint.
l Proximally, lateral to medial-scaphoid, lunate, tri- l Articular surfaces: head of humerus with shallow

quetral (plus attached pisiform). glenoid fossa of scapula (deepened somewhat by
l Distally, lateral to medial trapezium, trapezoid, cap- the labrum glenoidale—a cartilaginous ring).
l Capsule: lax and attached around epiphyseal line of
itate, hamate. glenoid and humeral head. Extends down to diaphy-
l Carpus is arched transversely, the palmar aspect sis on the medial aspect of the neck of the humerus.
Capsule lined by synovial membrane along tendon of
being concave. long head of biceps, which passes through joint.
l Arch is maintained by individual bones which are Synovium communicates with subcapsular bursa
beneath tendon of subscapularis.
broader posteriorly than anteriorly (except the lunate).
l Arch is also maintained by the flexor retinaculum

passing from the scaphoid and trapezium laterally
to the pisiform and hook of the hamate medially.

Radial notch of ulna Trochlear Olecranon
notch
Head of
radius Coronoid
process
Radial
tuberosity

Styloid process Head of ulna Styloid Dorsal tubercle
A Styloid process process Styloid process

B

Fig 3.3

The radius and ulna. A Anterior view, B posterior view.

The upper limb and breast 3 69

Distal phalanx Distal phalanx

Middle phalanx Second Middle phalanx
metacarpal
Proximal
Proximal phalanx phalanx
Head of
Head of phalanx
phalanx Head of fourth
metacarpal
Base of Second First
phalanx metacarpal metacarpal Base of
Sesamoid phalanx
Head of fourth bone Trapezoid
metacarpal Trapezium Capitate
Trapezoid Scaphoid Pisiform
Hamate Trapezium
Pisiform Hamate
Triquetrum Scaphoid Triquetrum

Lunate Capitate Lunate

AB

Fig 3.4
The carpals, metacarpals and phalanges. A Anterior view, B posterior view.

Acromion Clavicle
Supraspinatus
Humeral head Glenoid labrum
Greater tuberosity
Glenoid fossa
of humerus

Deltoid

Fig 3.5
Coronal MRI right shoulder joint.

l Stability depends largely on strength of surrounding Muscles acting on shoulder joint
muscles:
n rotator cuff l Abductors: supraspinatus, deltoid.
n long head of biceps l Adductors: pectoralis major, latissimus dorsi.
n deltoid, pectoralis major, latissimus dorsi, teres l Flexors: anterior fibres of deltoid, pectoralis major,
major, long head of biceps.
coracobrachialis.

70 SECTION ONE ANATOMY

l Extensors: latissimus dorsi, teres major, posterior l Deltoid then abducts to 90 .
fibres of deltoid. l Further movement to 180 is brought about by

l Medial rotators: pectoralis major, latissimus dorsi, rotation of the scapula by trapezius and serratus
teres major, subscapularis, anterior fibres of deltoid. anterior.
l As soon as abduction commences at the shoulder
l Lateral rotators: infraspinatus, teres minor, poste- joint, rotation of the scapula begins.
rior fibres of deltoid. l Movements of the scapula occur with reciprocal
movements of the sternoclavicular joint, i.e. elevate
The shoulder girdle the shoulder and the joint is depressed; move the
shoulder forwards and the joint moves backwards.
Movements of the shoulder joint itself cannot be l The scapula can be elevated (shrugging the shoul-
separated from those of the shoulder girdle as a ders) and depressed. Trapezius and levator scapu-
whole. lae elevate; gravity, pectoralis major and pectoralis
minor depress.
Sternoclavicular joint l The scapula can be protracted (moved forwards
round the chest wall) and retracted. Serratus ante-
l Articular surfaces: medial end of clavicle and sternum, rior and pectoralis minor protract; rhomboids and
intra-articular disc. middle fibres of trapezius retract.
l Rotation of the scapula upwards is carried out by
l Ligaments: costoclavicular ligament passes from trapezius and serratus anterior.
clavicle to first costal cartilage. This forms a fulcrum
so that when the outer end of the clavicle is raised, Clinical points
e.g. shrugging the shoulders, the medial end is
depressed. l In fractures of the clavicle, trapezius is unable to
support the weight of the arm. The patient therefore
Acromioclavicular joint supports the upper limb with the opposite hand. The
lateral fragment is depressed and drawn medially by
l Articular surfaces: lateral end of clavicle and the the shoulder adductors and the broken ends overlap.
acromion, incomplete articular disc. Slight elevation of the medial fragment occurs due to
sternocleidomastoid.
l Ligaments: coracoclavicular (conoid and trapezoid
ligaments). l Rupture of the tendon of supraspinatus results in in-
ability to actively initiate abduction of the shoulder.
l Movements: induced passively by scapula The patient develops a trick movement of tilting the
movement. body to the injured side so gravity allows the limb to
swing away from the trunk. Deltoid then comes into
l Dislocation of the outer end of the clavicle at the action.
joint is easily reduced; maintenance of reduction
is difficult, due to inclination of joint surfaces. l Supraspinatus tendinitis results in a painful arc of
shoulder movement between 60 and 120 . It is
Rotator cuff during this range of movement that the tendon
impinges against the overlying acromion and
l Sheath of tendons of short muscles of the shoulder coracoacromial ligament.
which surround and blend with all but the inferior
aspect of the joint. l Serratus anterior, which protracts the scapula and
keeps it applied to the chest wall, is supplied by
l Consists of supraspinatus, infraspinatus and teres the long thoracic nerve of Bell, C5, C6 and C7. Dam-
minor, which are inserted from above down into the age to this nerve (neck, breast or axillary surgery)
greater tuberosity of the humerus, and subscapularis, results in winging of the scapula.
which is inserted into the lesser tuberosity.
Elbow joint (Fig. 3.6)
l All the above muscles originate from the scapula.
l Supraspinatus is important in initiation of abduction Consists of three articulations and one synovial cavity.
l Humeroulnar: trochlea of humerus and trochlear
of the shoulder joint.
l Supraspinatus passes over the apex of the shoulder notch of ulna (hinge joint).

beneath the acromion and coracoacromial liga-
ment, from which it is separated by the subacromial
bursa.

Movements of shoulder girdle

l All but very slight glenohumeral movements are al-
ways accompanied by movements of the scapula
on the clavicle and of the clavicle on the manubrium.

l Abduction is initiated by supraspinatus (15 ).

The upper limb and breast 3 71

Shaft of humerus

Trochlea of humerus Olecranon fossa
of humerus
Coronoid process
of ulna Capitulum of humerus
Head of radius

Radial tuberosity

Fig 3.6
Coronal MRI left elbow joint.

l Humeroradial: capitulum and radial head (ball-and- l Condyloid joint: allows flexion, extension, adduction,
socket joint). abduction and circumduction.

l Proximal radioulnar: head of radius and radial notch l Movements are:
of ulna (pivot joint). n flexion: all muscles crossing the anterior aspect
of the joint
l Capsule: thin and lax anteriorly and posteriorly; n extension: all muscles crossing the posterior
thickened at sides to form medial and lateral collat- aspect of the joint
eral ligaments. The lateral ligament is attached to n adduction: flexor carpi ulnaris, extensor carpi
annular ligament, which holds the head of the ulnaris
radius in place. The medial and lateral epicondyles n abduction: flexor carpi radialis, extensor carpi
are extracapsular. radialis longus, abductor pollicis longus,
extensor pollicis longus.
l Movement: flexion and extension. Pronation and
supination occur at proximal radioulnar joint (with Joints of the hand
distal radioulnar joint).
Carpometacarpal joint
l Muscles acting on joint are:
n flexors: biceps, brachialis, brachioradialis, Thumb
forearm flexors l Saddle joint.
n extensors: triceps, anconeus l Flexion, extension, abduction, adduction, opposition.
n pronators: pronator teres, pronator quadratus l Flexion/extension in plane parallel to palm.
n supinators: biceps, supinator. l Abduction/adduction in plane at right angle to

Wrist joint (Fig. 3.7) palm.
l Opposition: thumb opposes to little finger.
l Articular surfaces: distal radius and head of ulna, l Other carpometacarpal joints have limited gliding
the latter separated from the carpus by an articular
disc. Proximal articular surfaces of scaphoid, lunate, movement only.
triquetral.

72 SECTION ONE ANATOMY

Base of metacarpal bones

Hamate Trapezium
Trapezoid
Triquetral Capitate
Lunate Scaphoid

Head of ulna Radial styloid

Pronator quadratus l Profundus tendon pierces superficialis tendon over
proximal phalanx.
Fig 3.7
Coronal MRI left wrist joint. l Profundus flexes the distal phalanx.
l Superficialis flexes the middle phalanx.
Metacarpophalangeal joints l Both muscles flex the fingers and the wrist.

l 60 range of flexion/extension at metacarpophal- Long extensors
angeal joint of thumb.
l Extensor digitorum longus inserted into the extensor
l 90 at other metacarpophalangeal joints, together expansion.
with abduction, adduction and circumduction.
l Extensor indicis inserted into the medial side of the
l Abduction and adduction are impossible with the extensor digitorum longus to index finger.
metacarpophalangeal joints flexed.
l Extensor digiti minimi inserted into the medial
l Metacarpophalangeal joints of fingers (not thumb) side of extensor digitorum longus to the little
are joined by deep transverse ligaments which finger.
prevent them spreading during a firm grip.
l They extend the fingers and wrist.
Interphalangeal joints
Extensor expansion (Fig. 3.8)
l Hinge joints.
l Flexion/extension only. l Covers the dorsum of the proximal phalanx and
l Collateral ligaments lax in extension and taut in sides of its base.

flexion. l Attaches by central slip into the base of middle
phalanx and two lateral slips into the base of
Muscles controlling the hand distal phalanx.

Long flexors l Receives the insertion of the interossei and
lumbricals.
l Flexor digitorum profundus: inserted into base of
distal phalanx.

l Flexor digitorum superficialis: inserted into sides of
middle phalanx.

The upper limb and breast 3 73

Distal phalanx Middle phalanx Proximal phalanx

Extensor
digitorum

Interosseous

A Extensor expansion Lumbrical

Extensor
digitorum
Interosseous

Lumbrical

B Flexor digitorum Flexor digitorum

superficialis profundus

Fig 3.8

The extensor expansion and tendons of a finger. A Dorsal view, B lateral view.

Small muscles of the hand Muscles of the little finger (hypothenar
eminence)
Interossei
l Arise from the sides and front of metacarpals. l Abductor digiti minimi.
l Abduct and adduct the fingers. l Opponens digiti minimi.
l Insert into the extensor expansion. l Flexor digiti minimi.
l Flex the metacarpophalangeal joints.
l Extend the interphalangeal joints. Muscle actions

Lumbricals l Flexor digitorum profundus flexes the distal
l Arise from the four profundus tendons. phalanx.
l Insert into the extensor expansion.
l Flex the metacarpophalangeal joints. l Flexor digitorum superficialis flexes the middle
l Extend the interphalangeal joints. phalanx.

Muscles of the thumb l Profundus and superficialis acting together flex the
fingers and wrist.
Long muscles
l Flexor pollicis longus: inserted into distal phalanx. l The interossei and lumbricals flex metacarpophal-
l Extensor pollicis longus: inserted into the distal angeal joints and extend the interphalangeal joints.

phalanx. l The interossei plus abductor digiti minimi abduct
l Extensor pollicis brevis: inserted into proximal and adduct the fingers.

phalanx. l Extensor digitorum has a weak abduction action.
l Abductor pollicis longus: inserted into the first l The long flexors have a weak adduction action.
l The abductor/adductor actions of extensor digi-
metacarpal.
torum and the long flexors are eliminated by placing
Short muscles (thenar eminence) the hand flat on a table. Abduction/adduction then
l Adductor pollicis: inserted into base of proximal become the actions of the intrinsic muscles only.
l The above can be tested by gripping a card between
phalanx. the fingers (tests T1 and partly ulnar nerve integrity).
l Flexor pollicis brevis: inserted into base of proximal
VEINS OF THE UPPER LIMB
phalanx.
l Abductor pollicis brevis: inserted into base of l Important in cannulation.
l Important in creation of arteriovenous fistula for
proximal phalanx.
l Opponens pollicis: inserted along the first dialysis.

metacarpal.

74 SECTION ONE ANATOMY

Superficial veins Clinical points

l Commence as dorsal venous network on dorsum of l The cephalic vein at the wrist is very constant and
hand. available for cannulation and for the formation of
radiocephalic (Cimino–Brescia) fistulae for dialysis
l Dorsal venous network drains into lateral cephalic (the radial artery is in close proximity).
vein and dorsal basilic vein.
l Avoid injection of irritant drugs into the veins at the
Cephalic vein elbow. There is a risk of accidentally entering the
brachial artery or a superficially placed aberrant
l Lies subcutaneously just behind the radial styloid, ulnar artery. Drug addicts are not aware of these
where it is very constant in position. anatomical relations!

l Runs up the anterior aspect of the forearm. Deep veins
l Lies in groove along the lateral border of biceps in
l Venae comitantes (accompanying the arteries).
the upper arm. l Usually in pairs or multiple.
l Passes to the deltopectoral triangle. l Nuisance value when exposing deep arteries, to
l Pierces the clavipectoral fascia to enter the axillary
which they are closely applied.
vein.
l Is superficial until it reaches the deltopectoral ARTERIES OF THE UPPER LIMB

triangle. (Fig. 3.9)

Basilic vein l Axillary.
l Brachial.
l Runs along the posteromedial aspect of the forearm. l Radial.
l Passes to the anterior aspect of the elbow on the l Ulnar.

medial side. Axillary
l Runs in the groove along the medial border of
l Commences at the lateral border of the 1st rib as
biceps. the continuation of the subclavian artery.
l Pierces the deep fascia at the middle of the upper
l Ends at the lower border of teres major to become
arm. the brachial artery.
l Joins venae comitantes of brachial artery, eventu-
l Divided into three parts by pectoralis major:
ally forming the axillary vein. n First part gives off one branch:
l superior thoracic artery.
Veins at the elbow n Second part gives off two branches:
l acromiothoracic artery
l Variable pattern. l lateral thoracic artery.
l Median cubital vein connects the cephalic and basi-

lic vein.
l The veins are separated from the underlying bra-

chial artery by the tough bicipital aponeurosis.

Radial artery Deep palmar arch
Anterior interosseous
Proper palmar
artery digital artery
Ulnar artery
Common palmar
Fig 3.9 digital artery
MRA left forearm and hand.

The upper limb and breast 3 75

n Third part gives off three branches: l Pierces first dorsal interosseous and adductor
l subscapular artery pollicis to contribute to deep palmar arch.
l anterior circumflex humeral artery
l posterior circumflex humeral artery. Ulnar artery

l Relations: brachial plexus cords surround the artery, l Commences at level of neck of radius (frequently
i.e. the lateral, medial and posterior cords. bifurcation may be higher).

Brachial artery l Passes deep to muscles from common flexor origin.
l Lies on flexor digitorum profundus, overlapped by
l Commences at the lower border of teres major as a
continuation of the axillary artery. flexor carpi ulnaris.
l Crossed superficially by the median nerve sepa-
l Terminates at the level of the neck of the radius
where it divides into the radial and ulnar artery. rated from it by the deep head of pronator teres.
l Distally in the forearm it becomes superficial be-
l It lies immediately below the deep fascia in most of
its course where it is readily accessible, e.g. for tween the tendons of flexor carpi ulnaris and flexor
brachial embolectomy. digitorum profundus.
l Crosses in front of the flexor retinaculum to form the
l It is crossed superficially from lateral to medial side superficial palmar arch with the superficial branch
by the median nerve at the level of midhumerus. of the radial artery.
l The ulnar nerve accompanies the artery on its
l High bifurcation of the artery is not unusual. medial side in the distal two-thirds of the forearm
and across the flexor retinaculum.
Radial artery
BRACHIAL PLEXUS (Fig. 3.10)
l Commences at the level of the radial neck lying on
the tendon of biceps (frequently bifurcation may be Partly in the neck and partly in axilla, the plexus is
higher). composed as follows:
l roots: between scalenus anterior and scalenus
l Overlapped by brachioradialis in its upper half.
l In the distal forearm it lies between brachioradialis medius
l trunks: in the posterior triangle of the neck
and flexor carpi radialis where it can be palpated at l divisions: behind the clavicle
the wrist. l cords: in the axilla.
l It is closely related to the radial nerve in the middle
of the forearm. Roots (5)
l Distal to the wrist the branches given off contribute
to the superficial palmar arch. l Anterior primary rami of C5, 6, 7, 8, T1.
l Passes deep to tendons of abductor pollicis longus
and extensor pollicis brevis to enter the anatomical
snuff box where it is palpable.

C5 Axillary nerve
C6
Musculocutaneous
C7 nerve
C8

T1
Roots

Upper trunk
Middle trunk
Lower trunk
Anterior and posterior

divisions
Lateral cord

Medial cord
Posterior cord

Ulnar nerve Radial nerve Fig 3.10
Median nerve The brachial plexus.

76 SECTION ONE ANATOMY

Trunks (3) The brachial plexus can be pre-fixed or post-fixed on
rare occasions. A pre-fixed plexus has a contribution
l Upper (C5, 6) from C4; a post-fixed from T2.
l Middle (C7)
l Lower (C8, T1). Nerves of the upper limb

Divisions (6) l Axillary.
l Radial.
l Each trunk divides into anterior and posterior l Musculocutaneous.
divisions. l Median.
l Ulnar.
Cords (3)
Axillary
l Lateral: fused anterior divisions of upper and middle
trunks. l Root value C5, 6.
l Arises from posterior cord.
l Medial: anterior division of lower trunk. l Winds round surgical neck of humerus.
l Posterior: fusion of all three posterior divisions. l Accompanied by circumflex humeral arteries.
l Muscular branches to deltoid, teres minor.
Nerves l Cutaneous branch supplying sensation to skin over

From the continuation of the cords: deltoid.
l musculocutaneous nerve: from the lateral cord
l ulnar nerve: from the medial cord Radial nerve
l radial nerve: from the posterior cord
l axillary nerve: from the posterior cord l Root value C5, 6, 7, 8, T1.
l median nerve: from a cross communication between l Arises from the posterior cord.
l Lies initially behind the axillary artery.
lateral and medial cords. l Passes posteriorly between the long and medial

Branches of the brachial plexus head of the triceps.
l Accompanied by profunda brachii artery.
Roots l Lies in the spiral groove of the humerus.
l Nerve to rhomboids. l Pierces the lateral intermuscular septum at the
l Nerve to subclavius.
l Nerve to serratus anterior (long thoracic nerve of lower third of the humerus and enters anterior
compartment.
Bell, C5, 6, 7). l Lies between brachialis and brachioradialis.
l Gives off posterior interosseous nerve at level of
Trunks lateral epicondyle.
l Suprascapular: upper trunk; supplies supraspinatus l Radial nerve continues as superficial branch to
brachioradialis.
and infraspinatus. l Above wrist emerges posteriorly from under bra-
chioradialis and supplies sensation by cutaneous
Cords branches to posterior aspect of radial three and a
Lateral half digits.
l Musculocutaneous. l Main radial nerve supplies triceps, anconeus,
l Lateral pectoral. brachioradialis, extensor carpi radialis longus and
l Lateral root of median. part of brachialis.
l Posterior interosseous branch supplies supinator,
Medial abductor pollicis longus and all remaining extensor
l Medial pectoral nerve. muscle.
l Medial cutaneous nerve of the arm and forearm. l Cutaneous supply is to the back of the arm, the
l Ulnar nerve. flexor and radial aspects of the dorsum of the hand.
l Medial root of median.
Musculocutaneous nerve
Posterior
l Thoracodorsal nerve (to latissimus dorsi). l Root value C5, 6, 7.
l Subscapular nerve. l Continuation of lateral cord of brachial plexus.
l Axillary nerve.
l Radial nerve.

The upper limb and breast 3 77

l Pierces coracobrachialis and runs between biceps l Accompanies ulnar artery in distal two-thirds of
and brachialis. forearm, which lies to its radial side.

l Supplies biceps, brachialis and coracobrachialis. l Gives off a dorsal cutaneous branch 5 cm above the
l Innervates the skin of the lateral forearm. wrist, which is sensory to the dorsal aspect of the
ulnar one and a half fingers.
Median nerve
l Crosses the flexor retinaculum superficially.
l Root value C6, 7, 8, T1. l Supplies:
l Arises from the joining of branches of the medial
n flexor carpi ulnaris
and the lateral cord of the plexus. n medial half of flexor digitorum profundus
l Lies initially anterior to the third part of the axillary n hypothenar muscles
n interossei
artery. n medial two lumbricals
l Continues along the lateral aspect of the brachial n adductor pollicis.

artery. ANATOMY OF NERVE LESIONS
l Crosses superficial (occasionally deep) to the bra-
Brachial plexus
chial artery at midhumeral level to lie on the medial
side of the brachial artery. Erb’s (Erb–Duchenne) paralysis
l Enters the forearm between the heads of pronator
teres. l Forced downward traction on arm during birth.
l At this level it gives off the anterior interosseous l Fall on side of head and shoulder, forcing the two
branch.
l The median nerve then lies on the deep aspect of apart.
flexor digitorum superficialis. l Root C5, C6 affected.
l Superficial at the wrist lying to the ulnar side of l Paralysis of deltoid, supraspinatus, infraspinatus,
flexor carpi radialis in the midline.
l Gives off palmar cutaneous branch at the wrist, brachialis, biceps.
which passes superficial to the flexor retinaculum l Arm hangs limply by side (abductors paralysed) with
and supplies the palmar skin over the thenar
eminence. forearm pronated (brachialis and biceps flex and
l It then passes deep to the flexor retinaculum, giving supinate) and palm facing backwards (waiter’s tip
a branch to the thenar muscles beyond the distal position).
skin crease.
l Supplies in its course all muscles of the flexor Klumpke’s paralysis
aspect of the forearm (except flexor carpi ulnaris
and the ulnar half of flexor digitorum profundus), l Upward traction on arm may damage T1 (e.g.
the muscles of the thenar eminence and the breech delivery).
radial two lumbricals.
l Supplies sensation to the radial three and a half l Intrinsic muscles of hand paralysed.
digits and skin of the radial side of the palm. l Claw hand:

Ulnar nerve n unopposed action of long flexors and long
extensors
l Root value C7, 8, T1.
l Formed by the medial cord of the plexus. n extensors extend metacarpophalangeal joints
l Lies medial to the axillary and brachial artery to n flexors flex the interphalangeal joints
n use of the intrinsic muscles is lost; therefore,
midhumerus.
l Pierces the medial intermuscular septum, descend- they cannot extend the interphalangeal joints,
and hence clawing occurs due to unopposed
ing on the anterior surface of the triceps. action of the long flexors.
l Passes behind the medial epicondyle (where it is l Associated area of numbness along inner and upper
arm and forearm centred on elbow joint level.
palpable). l May be associated with Horner’s syndrome due to
l Descends between flexor carpi ulnaris and flexor traction on sympathetic chain.
l Wasting of small muscles of hand; ‘channels’
digitorum profundus and then lies superficial between metacarpals, wasting of first dorsal
on the radial side of the tendon of flexor carpi interosseus.
ulnaris. l Similar lesions may occur with Pancoast’s tumour
or a cervical rib.

78 SECTION ONE ANATOMY

Axillary nerve l Damage at the wrist results in:
n clawing of the hand similar to Klumpke’s paral-
l Damaged in fracture of surgical neck of humerus or ysis, except less clawing in second and third
anterior dislocation of the shoulder joint. digits because of median nerve supply to
lumbricals, which is intact
l Deltoid paralysed therefore abduction lost. n sensory loss over medial one and a half fingers.
l Small patch of anaesthesia over the insertion of
l Damage at the elbow results in:
deltoid (‘badge area’). n similar lesion to wrist except less clawing in
fourth and fifth fingers, as flexor digitorum pro-
Radial nerve fundus to those fingers is paralysed
n flexor carpi ulnaris is paralysed, therefore a
l Damaged in fractures of midshaft of humerus, or tendency to radial deviation at the wrist.
compression of nerve against humerus when a
drunk falls asleep with the arm over the back of l Damage to ulnar nerve leaves a remarkably efficient
a hard chair, trapping the nerve between the chair hand. Confirmation of the diagnosis is by testing for
and the humerus (‘Saturday night palsy’). Also lack of sensation of the medial one and a half digits,
pressure from crutch, but axillary weight-bearing and loss of abduction and adduction of the fingers
crutches are rare nowadays. with the hand flat on a table (excludes trick move-
ments of long flexors and extensors).
l Posterior interosseous may be damaged in fractures
or dislocations of the radial head or in the surgical SPACES OF THE HAND
approach to the radial head.
Pulp spaces of fingers (Fig. 3.11)
l Results in wrist drop if main nerve is damaged.
l Damage to posterior interosseous branch allows l Pulp space is fat packed between fibrous septa from
skin to periosteum.
extension of the wrist (due to extensor carpi radialis
longus which is supplied by the main radial nerve l Blood vessels have to pass through this space, except
before the posterior interosseous branch is given off). the proximal branch to the base of the distal phalanx.
l Small area of anaesthesia on the skin on dorsum of
first web space. l Pulp space infection increases the pressure in the
space. This may result in arterial thrombosis and
Median nerve necrosis of distal phalanx with the exception of its
base, which is spared because of the proximal branch.
l Damaged in lacerations at the wrist and supracon-
dylar fractures of the humerus. Bursae of the hand and synovial
tendon sheaths (Fig. 3.12)
l Damage at the elbow results in:
n loss of forearm pronation l Flexor tendons traverse a fibro-osseous tunnel for
n weakness of wrist flexion with ulnar deviation each digit.
(flexion depends on flexor carpi ulnaris and
the medial half of flexor digitorum profundus) l The fibrous sheaths end at insertion of flexor digi-
n loss of sensation on the lateral palm and radial torum profundus.
three and a half digits.
Branch to base of
l Damage at wrist results in: distal phalanx (does not
n paralysis of the thenar muscles (except adduc- pass through pulp space)
tor pollicis)
n paralysis of radial two lumbricals Distal pulp
n loss of sensation over radial three and a half digits. space

l Damage of the nerve at both sites causes loss of Fibrous
accurate opposition, and the loss of cutaneous septa
innervation makes this a serious injury with loss
of tactile response. Digital Branches to shaft of distal
artery phalanx passing through
Ulnar nerve the pulp space

l Damage at medial epicondyle, e.g. fracture of the Fig 3.11
medial epicondyle or dislocations of the elbow;
lacerations at wrist. Distal pulp space of a finger showing the
blood supply to the distal phalanx.

The upper limb and breast 3 79

Synovial sheath for Thenar space
flexor tendons to
l Superficial to second and third metacarpals and
middle finger adductor pollicis.

Fibrous flexor l Separated from midpalmar space by fibrous partition.
sheath l Infection in spaces is usually from a direct penetrat-

Synovial sheath for ing injury or neglected tendon sheath infection.
flexor pollicis l Infection rare in spaces, due to antibiotics.
longus Palmar infections may result in marked dorsal
oedema. This is due to the thick palmar skin being
Synovial firmly bound down to the underlying palmar aponeu-
sheath rosis. In contrast, the skin of the dorsum of the hand is
loose and fluid can readily collect deep to it.
for flexor
tendons Palmar aponeurosis

Flexor l Part of the deep fascia of the hand.
retinaculum l Blends with the fibrous flexors sheath of the fingers.
l Attached to sides of proximal and middle phalanges.
Fig 3.12 l Dupuytren’s contracture results in thickening and

The synovial sheaths of the wrist and hand, anterior contraction of the palmar fascia with flexion of
view. the metacarpophalangeal joints and proximal inter-
phalangeal joints. The distal interphalangeal joint is
not involved.

l The fibrous sheaths are lined by synovial membrane. SPECIALISED AREAS OF THE ARM
l Second, third and fourth fingers have synovial
Axilla
sheaths that close proximally at the metacarpal
head. The axilla is a pyramidal space through which struc-
l Synovial sheaths of thumb and little finger extend tures from the head, neck and thorax pass into the
proximally into the palm. arm, and structures from the arm pass into the thorax.
l Synovial sheath of long flexor of the thumb extends Being pyramidal it has a base, four walls and an apex.
through the palm deep to the flexor retinaculum to l Base: skin and fascia of the armpit.
2.5 cm proximal to wrist (radial bursa). l Medial wall: rib cage covered by serratus anterior.
l Synovial sheath of fifth finger forms the ulnar bursa, l Lateral wall: bicipital groove of the humerus.
which encloses all finger tendons in the palm and l Anterior wall: pectoralis major and pectoralis minor.
extends proximally deep to the flexor retinaculum l Posterior wall: latissimus dorsi, teres major and
for 2.5 cm above the wrist.
l The radial and ulnar bursae may communicate. more superiorly supscapularis.
l Infection of the synovial sheath to second, third and l Apex is bounded anteriorly by the clavicle, first rib
fourth digits is confined to the finger. However
infection of the first and fifth sheaths may spread medially, and the acromion and superior border of
into the palm or from one bursa to another. the scapula posteriorly.
l Contents:
Palmar spaces
n brachial plexus
Midpalmar space n axillary artery
n axillary vein
l Behind the flexor tendons and ulnar bursa. n lymph nodes
l In front of the third, fourth and fifth metacarpals. n fat.
l First and second metacarpals are cut off by adduc-
Antecubital fossa
tor pollicis which arises from the shaft of third
metacarpal. l Bounded by pronator teres medially and brachio-
radialis laterally.

l Its floor is formed by brachialis and supinator.

80 SECTION ONE ANATOMY

l The roof is formed by skin, superficial fascia, and Structures around the wrist joint
deep fascia augmented by the bicipital aponeurosis.
These are shown in Figure 3.14.
l Contents include the brachial artery and medial to it
the median nerve. LYMPHATICS OF THE UPPER LIMB

Carpal tunnel (Fig. 3.13) l Superficial and deep lymphatics. Superficial lym-
phatics accompany the veins and the deep lym-
l The flexor retinaculum forms the roof of a tunnel, phatics accompany the arteries.
the floor and walls of which are formed by the
concavity of the carpal bones. l Few superficial lymph nodes in the upper limbs:
chiefly the epitrochlear nodes.
l Within this tunnel are the tendons of flexor digi-
torum superficialis, flexor digitorum profundus, l Efferents from epitrochlear nodes pierce the deep
flexor pollicis longus and flexor carpi radialis (the fascia and end in the axillary nodes.
latter tendon is in its own separate osseofascial
compartment). Axillary lymph nodes

l The most important structure to pass through the l Drain the following:
tunnel is the median nerve. Any lesion diminishing n the breast
the size of the tunnel may result in compression n the pectoral region
of the median nerve (carpal tunnel syndrome). n the upper abdominal wall down to the umbilicus
n the skin of the back down to the iliac crest
l The superficial palmar branch of the nerve is given n the upper limb.
off proximal to the flexor retinaculum, and therefore
there is no sensory impairment on the lateral side l Arranged in five groups, although these are not distinct:
of the palm if the nerve is compressed in the carpal n lying deep to pectoralis major along the lower
tunnel. border of pectoralis minor
n posterior: along the subscapular vessels
Anatomical snuffbox n lateral: along the axillary vein
n central: in the axillary fat
l Medial border formed by tendon of extensor pollicis n apical: immediately behind the clavicle at the
longus. apex of the axilla above pectoralis minor, and
arranged along the axillary vein (all other axil-
l Lateral border by the tendons of abductor pollicis lary nodes drain through this group).
longus and extensor pollicis brevis.
l From these nodes the subclavian lymph trunk emerges.
l Contents include the base of the metacarpal l Surgical anatomy of the axillary lymph nodes is im-
of the thumb, the trapezium, the scaphoid, the
radial styloid and the dorsal branch of the radial portant in relation to breast surgery. From this point
artery. of view they are classified into three levels:

l Important clinically as tenderness can be felt in the n level 1 nodes: present below and lateral to the
anatomical snuffbox with fractures of the scaphoid. inferolateral border of pectoralis minor

l Dorsal branch of the radial artery lies close to n level 2 nodes: behind pectoralis minor
the cephalic vein and therefore this is an appropriate n level 3 nodes: above the upper border of
site for creating arteriovenous fistulae for dialysis.
pectoralis minor.

Flexor Ulnar artery
retinaculum Ulnar nerve
Thenar muscles
Hypothenar muscles
Flexor carpi Median nerve
radialis
Flexor tendons
Trapezium (superficialis plus
profundus)
Flexor pollicis Hamate
longus

Trapezoid Capitate

Fig 3.13

Transverse section through carpal tunnel at level of distal carpal bones, showing the relations of structures to the
flexor retinaculum.

The upper limb and breast 3 81

Palmaris Median nerve Flexor digitorum
longus superficialis
Flexor carpi
radialis Flexor digitorum
profundus
Flexor pollicis Ulnar artery
longus
Flexor carpi
Radial ulnaris
artery
Ulnar nerve
Abductor pollicis
longus

Extensor pollicis Ulnar styloid
brevis process

Extensor carpi Extensor Extensor carpi
radialis longus indicis ulnaris

Extensor carpi Extensor digiti
radialis brevis minimi
Extensor
Extensor pollicis digitorum
longus

Fig 3.14

Relations around the wrist. Transverse section through distal right radius and ulna styloid, made with
hand and forearm in full supination and viewed from distal aspect.

DISTRIBUTION OF DERMATOMES l From the intercostal arteries via the lateral perforat-
AND CUTANEOUS NERVES IN ing branches.
THE UPPER LIMB
l Venous drainage is to the corresponding veins.
These are shown in Figure 3.15 (dermatomes) and
Figure 3.16 (cutaneous nerves). Lymphatic drainage

THE BREAST l Along tributaries of the axillary vessels to the
axillary lymph nodes.
l The female breast is made up of:
n fat l Along tributaries of the internal mammary vessels to
n fibrous tissue the internal mammary chain.
n glandular tissue.
l Although there is free communication between the
l Fat predominates in the non-lactating breast. lymphatic vessels lying between the lobules of the
l 15–20 lobules of glandular tissue. breast, there is a tendency for the lateral part of
l Lobules separated by fibrous septa running from the the breast to drain towards the axilla and the medial
part to drain to the internal mammary chain.
subcutaneous tissues to the fascia of the chest wall
(the ligaments of Astley Cooper). Male breast
l Each gland drains into a lactiferous duct which
converges towards the nipple, and each becomes l Rudimentary.
dilated to form a lactiferous sinus beneath the l Small, primitive ducts may be present, supported by
areola.
l The areola is lubricated by the glands of fibrous tissue and fat.
Montgomery—large modified sebaceous glands. l Carcinoma may occur.

Blood supply Clinical points

l The axillary artery via lateral thoracic and acro- l When spread of a carcinoma of the breast has infil-
miothoracic branches. trated normal pathways of lymphatic drainage, it
may spread by other routes to:
l The internal mammary (thoracic) artery via its n lymphatics of the opposite breast
perforating branches. n contralateral axillary lymph nodes
n inguinal lymph nodes
n cervical lymph nodes.

82 SECTION ONE ANATOMY C5

C3
C4

T3
C5

T2

Anterior T1
C6 Posterior

C6
C7

C8

Fig 3.15
Dermatomes of the upper limb.

Posterior cutaneous
nerve of arm

Supraclavicular nerve

Upper lateral cutaneous Medial
nerve of arm cutaneous
nerve of arm
Intercostobrachial nerve

Lower lateral cutaneous
nerve of arm

Posterior
cutaneous
nerve of forearm

Medial Lateral cutaneous Medial
cutaneous nerve of forearm cutaneous
nerve of forearm
nerve of Radial nerve
forearm Ulnar nerve

Ulnar nerve

Median nerve
AB

Fig 3.16
The territories of supply of the cutaneous nerves of the upper limb. A Anterior view, B posterior view.

The upper limb and breast 3 83

l Incisions in the breast are made radially, to avoid l The nipple may fail to evert and it is important to
cutting across the line of the ducts. know if this has been present since birth or is a
recent event, as the latter may indicate carcinoma
l A blocked duct may become dilated during lactation or duct ectasia.
to form a galactocoele.
l Supernumerary nipples may be present along the
l Glands of Montgomery become enlarged in preg- ‘milk line’ (line of mammary gland of primitive
nancy to form Montgomery’s tubercles. mammals).

l Dimpling of the skin over a carcinoma of the breast
is the result of malignant infiltration and contraction
of Cooper’s ligaments.

OSCE SCENARIOS OSCE scenario 3.2

OSCE scenario 3.1 A patient in chronic renal failure is being assessed
for construction of a radiocephalic arteriovenous
A patient attempts suicide by slashing the flexor fistula at the left wrist.
aspect of his wrists in a radial to ulnar direction. 1. Where would you palpate the radial and ulnar
1. Which tendons are likely to be divided and how
pulses to assess their integrity?
would you test their integrity? 2. The ulnar pulse is not readily palpable. What test
2. Which nerves are likely to be affected?
3. How would you test the integrity of these would you use to assess the integrity of the
circulation to the hand and how would you
nerves? perform it?
Answers in Appendix page 451

SECTION ONE ANATOMY

CHAPTER 4

The lower limb

THE PELVIC GIRDLE l Superior ramus connects the acetabulum and
symphyseal articular surfaces of the pubis.
The pelvis is made up of:
l innominate (hip) bones l The inferior ramus extends downwards from the
l the sacrum tubercle to its point of fusion with the ischium.
l the coccyx.
These bones are bound to one another by strong l The inguinal ligament attaches to the pubic
ligaments. tubercle.

The hip bone (os innominatum) (Fig. 4.1) l The adductors, perineal muscles and perineal
membrane attach to the inferior ramus.
This consists of three fused bones:
l ilium Ischium
l pubis
l ischium. l J-shaped bone with a massive body posteriorly
bearing the ischial component of the acetabulum.
Ilium
l Inferiorly is the ischial tuberosity, which bears the
l Anterosuperiorly is a broad, thin blade for muscle weight of the sitting trunk.
attachment and visceral protection.
l Anteriorly is the ramus uniting with the pubis.
l Posteroinferiorly is a thick, weight-transmitting bar l The posterior border of the body bears the ischial
with an articular surface at each end (laterally for
the head of the femur; medially for the sacrum). spine, separating the greater sciatic notch superi-
orly from the lesser sciatic notch inferiorly.
l Iliac crest runs superiorly between the anterior and l The hamstrings and short hip rotators (except piri-
posterior superior iliac spines; below each of these formis) attach to the outer aspect of the tuberosity
lies the corresponding inferior iliac spine. and the lower body.
l The ischium and pubis together form the circumfer-
l Posterior border of ilium curves inferiorly between ence of the obturator foramen.
the sacroiliac joint and the ischial spine, forming l All three bones fuse together at the acetabulum and
the greater sciatic notch. form a socket for the femoral head. The acetabulum
consists of about one-fifth pubis and two-fifths each
l The glutei and tensor fasciae latae muscles attach of ilium and ischium.
to the outer aspect of the blade of the ilium, produc-
ing well-defined ridges. The sacrum (Fig. 4.2)

l The three-layered abdominal wall muscles attach to l Made up of five fused vertebrae and roughly trian-
the anterior two-thirds of the crest. gular in shape.

l Latissimus dorsi and erector spinae attach posteri- l Anterior border of upper part forms the sacral
orly to the crest. promontory.

l The inguinal ligament attaches laterally to the ante- l The anterior aspect comprises:
rior superior iliac spine. n a central mass
n a row of four anterior sacral foramina on each
Pubis side (transmitting the upper four sacral anterior
primary rami)
l Shaped like a rotated L. n the lateral masses of the sacrum.
l Comprises a body and superior and inferior pubic

ramus.

84

The lower limb 4 85

Inferior gluteal line Anterior gluteal line

Ilium Posterior gluteal line
Anterior superior Posterior superior
iliac spine
iliac spine

Iliopubic eminence Acetabulum

Superior ramus Acetabular
of pubis notch
Ischium
Pubic Ischial
tubercle tuberosity
Pubic crest
Iliac fossa
Obturator foramen

Inferior
ramus of
A pubis

Articular Anterior Fig 4.1
surface for superior
iliac spine The innominate bone. A Lateral
sacrum view, B medial view.
Greater sciatic Anterior
notch inferior
iliac spine
Ischial spine
Lesser sciatic Arcuate line
Pectinal line
notch
Obturator foramen Pubic
tubercle
Ischial tuberosity
Surface for
B symphysis
pubis

l The superior aspect of the lateral mass on each side l Extending from the sacral canal is a row of four
forms the ala. posterior sacral foramina on each side.

l Posteriorly lies the sacral canal (the continuation of l Inferiorly, the vertebral canal terminates in the sa-
the vertebral canal), surrounded by short pedicles, cral hiatus, which transmits the fifth sacral nerve.
strong laminae and small spinous processes.
l On either side of the hiatus lies the sacral cornu.

86 SECTION ONE ANATOMY

Line of Foramina for
vertebral fusion anterior primary rami

Ala Sacral
promontory
Lateral
mass Sacroiliac
joint

Coccyx Coccyx

AB

Spinous Foramina for
process posterior primary rami

Sacral
hiatus

Coccyx Fig 4.2
C
The sacrum and coccyx. A Ventral surface, B lateral surface,
C dorsal surface.

l On the lateral aspect of the sacrum is a large facet for JOINTS AND LIGAMENTS OF
articulation with the corresponding surface of the ilium. THE PELVIS (Figs 4.3 and 4.4)

l Occasionally the fifth lumbar vertebra fuses with the Symphysis pubis
sacrum.
l Like all symphyses it lies in the median plane
l The dural sheath terminates distally at the second and comprises a disc of fibrocartilage firmly
piece of the sacrum. fixed between two articular surfaces of hyaline
cartilage.
l Beyond this the sacral canal contains the extradural
space, the cauda equina and the filum terminale. l Surrounded and strengthened by fibrous
ligaments.
Coccyx
l A non-synovial cavity often appears in the disc of
l Made up of three to five fused vertebrae, which fibrocartilage in adult life.
articulate with the sacrum.

Iliolumbar ligament The lower limb 4 87

Lumbosacral Sacrum
ligament Iliac crest

Anterior sacro-iliac Anterior superior
ligament iliac spine
Sacrospinous
Anterior ligament
inferior Sacrotuberous
iliac spine ligament
Sacrococcygeal
Symphysis
ligament pubis
Coccyx

Fig 4.3
The male pelvis showing the major ligaments, viewed from the front and slightly above.

Ilium

Ischiofemoral Sacrum
ligament
Posterior
sacro-iliac
ligament

Sacrospinous
ligament

Coccyx

Sacrotuberous
ligament

Fig 4.4

The ligaments of the pelvis and femur,
posterior view.

Sacro-iliac joints n in the elderly they are almost entirely fibrous,
with irregular surfaces.
l Large and very stable joints connecting the girdle
proper with the axial skeleton. l Stability of the sacroiliac joints is dependent on
powerful ligaments:
l Joints change in character with age: n posterior sacroiliac ligaments, which oppose the
n in the very young they are synovial, with almost tendency for downwards and backwards displace-
plane surfaces ment of the sacrum between the hip bones

88 SECTION ONE ANATOMY

n the iliolumbar ligaments attaching to the trans- Gluteus maximus
verse processes of L5 and the iliac crest.
Origin
l The sacrotuberous and sacrospinous ligaments
attach the sacrum to the ischium and oppose l Ilium above and behind posterior gluteal line.
downwards rotation of the sacrum in the sagittal l Sacrum and coccyx.
plane. l Sacrotuberous ligament.

l The sacrotuberous ligament passes from the ischial Insertion
tuberosity to the side of the sacrum and coccyx.
l lliotibial tract: three-quarters.
l The sacrospinous ligament passes from the ischial l Gluteal tuberosity of femur: one-quarter.
spine to the side of the sacrum and coccyx.
Nerve supply
l The sacrospinous and sacrotuberous ligaments
define two important exits from the pelvis: l Inferior gluteal nerve (L5, S1, 2).
n the greater sciatic foramen, formed by the
sacrospinous ligament and the greater sciatic Actions
notch
n the lesser sciatic foramen, formed by the sacro- l Extension of the thigh.
tuberous ligament and the lesser sciatic notch. l Lateral rotator of the thigh.
l Balances pelvis on thigh (with psoas and iliacus).
l Major anatomical relations include: l Steadies femur on knee joint on standing (via
n sacroiliac joints: the internal iliac vessels pass
anteriorly iliotibial tract).
n pubic symphysis: urethra and deep dorsal vein
of the penis pass inferiorly. General points

GLUTEAL REGION (Fig. 4.5) l Large, coarse muscle with small nerve supply and
therefore not capable of fine or precise movements.
The muscles of the gluteal region are:
l Gluteus maximus. l Covers posterior part of gluteus medius.
l Gluteus medius. l Covers all short muscles around hip joints, the
l Gluteus minimus.
l Piriformis. sciatic nerve, the proximal part of hamstrings, both
l Obturator internus. sciatic foramina and the structures passing through
l Superior and inferior gemelli. them.
l Quadratus femoris. l Lower border overlaps ischial tuberosity on standing
l Tensor fasciae latae. (but not sitting) and the sacrotuberous ligament.
The glutei form the mass of the buttock. l Its lower border does not correspond to the gluteal
fold.

Iliac crest Gluteus maximus (cut)
Superior gluteal
artery and nerve Gluteus medius

Sacrum Gluteus maximus (cut
and reflected)
Cut inferior
gluteal nerve Cut inferior gluteal
nerve supplying
Sacrotuberous gluteus maximus
ligament
Piriformis
Internal pudendal
artery and nerve Sciatic nerve Fig 4.5
Greater trochanter The gluteal region.
Posterior cutaneous Quadratus femoris
nerve of thigh
Sciatic nerve

The lower limb 4 89

Gluteus medius Piriformis
Origin
Origin
l Anterior surface of sacrum.
l Outer surface of ilium between anterior and poste-
rior gluteal lines. Insertion

Insertion l Passes out of greater sciatic foramen to upper
border of greater trochanter.
l Lateral side of greater trochanter of femur.
Nerve supply
Nerve supply
l Directly from second and third sacral nerves.
l Superior gluteal (L4, 5, S1).
Actions
Action
l This and the following three small muscles cause
l Abduction of thigh. lateral rotation of the thigh.
l Tilting upwards of opposite side of pelvis.
l Gluteus medius of limb that is on the ground during Obturator internus
Origin
walking supports the pelvis and prevents it from tilt-
ing to the other side. l Obturator membrane and surrounding bone.

Gluteus minimus Insertion

Origin l Tendon leaves by lesser sciatic foramen to
insert into the greater trochanter on its medial
l Outer aspect of ilium between anterior and inferior surface.
gluteal lines.
Nerve supply
Insertion
l Nerve to obturator internus (L5, S1, 2).
l Anterior aspect of greater trochanter.
Gemelli (superior and inferior)
Nerve supply Origin

l Superior gluteal nerve (L4, 5, S1). l Upper and lower margins of lesser sciatic notch.

Action Insertion

l Abduction of thigh. l Sides of tendon of obturator internus.
l Medial rotation of thigh.
l Assists gluteus medius in walking to prevent pelvis Nerve supply

tilting. l Superior by nerve to obturator internus.
l Inferior by nerve to quadratus femoris.
Tensor fasciae latae
Quadratus femoris
Origin Origin

l Anterior part of iliac crest posterior to the anterior l Outer border of tuberosity of ischium.
superior iliac spine.
Insertion
Insertion
l Quadrate tubercle of upper part of trochanteric
l Iliotibial tract. crest.

Nerve supply Nerve supply

l Superior gluteal nerve (L4, 5, S1). l Nerve to quadratus femoris (L4, 5, S1).

Action

l Assists gluteus maximus in tightening the iliotibial
tract.

90 SECTION ONE ANATOMY

Greater and lesser sciatic foramina and outer quadrant of the buttock will therefore
avoid accidental injection into the sciatic nerve
Sacrotuberous and sacrospinous ligaments convert (see Fig. 4.17).
the sciatic notches into foramina.
BONES OF THE LEG AND FOOT
Greater sciatic foramen
The femur (Fig. 4.6)
Boundaries
l Superior and anterior: greater sciatic notch. l The largest bone in the body, being about 45 cm
l Posterior: sacrotuberous ligament. long.
l Inferior: sacrospinous ligament and ischial spine.
l Upper end of femur consists of the rounded head,
Structures passing through the foramen the neck and two processes, the greater and lesser
include: trochanters.
l Piriformis.
l Above piriformis: l Head forms two-thirds of a sphere, facing upwards
medially and slightly forwards.
n superior gluteal vessels
n superior gluteal nerve. l It is covered with cartilage, except at the
l Below piriformis: central fovea where the ligamentum teres is
n inferior gluteal vessels attached.
n inferior gluteal nerve
n internal pudendal vessels l The neck is 5 cm long and lies at an angle of 125
n internal pudendal nerves to the shaft (in the female the angle is slightly
n sciatic nerve smaller).
n posterior cutaneous nerve of thigh
n nerve to quadratus femoris l The greater trochanter is a massive process which
n nerve to obturator internus. can be palpated as the most lateral bony point in the
region of the hip.
Lesser sciatic foramen
l The lesser trochanter is much smaller and it is
Boundaries situated most posteriorly on the femur.
l In front: body of ischium and sacrospinous ligament.
l Behind: sacrotuberous ligament. l The junction between neck and shaft is marked
anteriorly by the intertrochanteric line, laterally
Structures passing through the foramen by the greater trochanter, medially and posteri-
include: orly by the lesser trochanter and posteriorly by
l tendon of obturator internus the trochanteric crest which joins the two
l nerve to obturator internus trochanters.
l internal pudendal vessels
l pudendal nerve. l The femoral shaft is roughly circular in section at
its centre but is flattened posteriorly at each
Clinical points extremity.

l The buttock is a common site for intramuscular l The posterior surface carries a rough raised line in
injections. its middle third, i.e. the linea aspera. In the upper
and lower thirds, this line splits into two diverging
l It is important to remember that the buttock extends lines.
upwards as far as the iliac crest and laterally as far
at the greater trochanter. It does not just include the l Inferiorly the two diverging lines, i.e. the medial and
aesthetically pleasing mound. lateral supracondylar ridges, mark the medial and
lateral boundaries of a smooth, flattened area, i.e.
l The surface marking of the sciatic nerve is repre- the popliteal surface of the femur.
sented by a curved line joining the midpoint between
the posterior superior iliac spine and ischial tuberos- l The medial supracondylar line ends distally in the
ity with the midpoint between the ischial tuberosity adductor tubercle.
and the greater trochanter. Injections into the upper
l The lower end of the femur bears the prominent
condyles, which are separated by a deep intercon-
dylar notch posteriorly and join anteriorly to form the
articular surface for the patella.

l The lateral condyle is more prominent than the
medial and acts as a buttress to prevent lateral
displacement of the patella.

Greater trochanter Fovea Head The lower limb 4 91
Intertrochanteric line Head Neck
Neck Quadrate tubercle

Lesser trochanter Intertrochanteric
crest
Gluteal
tuberosity

Spiral line

Linea aspera
Shaft

Medial Lateral
supracondylar supracondylar
ridge
ridge
Popliteal surface
Adductor Adductor
tubercle tubercle Intercondylar
notch
Lateral epicondyle Medial
Lateral condyle condyle

A Medial
Fig 4.6 B epicondyle
The right femur. A Anterior view, B posterior view.

Blood supply of the femoral head fractures than extracapsular fractures because
intracapsular fractures are more likely to disrupt
l This is from: the retinacular blood flow.
n vessels from the hip capsule where this is l Fractures of the femoral neck result in shortening,
reflected onto the neck in longitudinal bands external rotation and adduction of the affected limb.
or retinacula (retinacular vessels) Shortening is due to the strength of the longitudi-
n vessels travelling up the diaphysis nally lying muscles, especially quadriceps and ham-
n an artery in the ligamentum teres, which is a strings. The adductors pull the limb superomedially.
negligible source in the adult. Instead of rotating about an axis between hip and
knee, the femur now rotates about the axis of its
l The chief source is from the retinacular vessels. shaft. Because of this, iliopsoas now acts as an
external rotator.
Clinical points l Fractures of the femoral shaft are accompanied by
considerable bleeding due to damage of the perfo-
l Fractures of the femoral neck completely interrupt rating branches of the profunda femoris artery,
the blood supply from the diaphysis. If the retinacula which are in close relation to the shaft.
are torn, avascular necrosis of the femoral head will
occur. Avascular necrosis of the femoral head is
much more likely to occur with intracapsular