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The mesenteries and layers of the peritoneum
lower layers of the coronary ligament with its sharp-edged right tri-
The transverse colon, stomach, spleen and liver each have attached to
angular ligament. The layers of the coronary ligament are widely
them two ‘mesenteries’adouble layers of peritoneum containing arteries
and their accompanying veins, nerves and lymphaticsawhile the small ment while the right layer turns back on itself to form the upper and
separated so that a large area of liver between themathe bare areaa
intestine and sigmoid colon have only one. All the other viscera are re- is directly in contact with the diaphragm. The inferior vena cava is
troperitoneal. The mesenteries and their associated arteries are as follows: embedded in the bare area (Fig. 14.3).
• The colon (Fig. 14.1): (1) The transverse mesocolon (the middle • From the undersurface of the liver another ‘mesentery’ passes from
colic artery). (2) The posterior two layers of the greater omentum. the fissure for the ligamentum venosum to the lesser curvature of the
• The stomach (Fig. 14.1): (1) The lesser omentum (the left and right stomach to form the lesser omentum.
gastric arteries and in its free border, the hepatic artery, portal vein and • The lesser omentum splits to enclose the stomach and is continuous
bile duct). (2) The anterior two layers of the greater omentum (the right with the two layers of the greater omentum already described. The
and left gastroepiploic arteries and their omental branches). lesser omentum has a right free border which contains the portal vein,
• The spleen (Fig. 14.2): (1) The lienorenal ligament (the splenic the hepatic artery and the common bile duct.
artery). (2) The gastrosplenic ligament (the short gastric and left gas- • In the region of the spleen there are two more ‘mesenteries’ which are
troepiploic arteries). continuous with the lesser and greater omenta. These are the lienorenal
• The liver (Fig. 14.3): (1) The falciform ligament and the two layers ligament, a double layer of peritoneum reflected from the front of the
of the coronary ligament with their sharp edges, the left and right trian- left kidney to the hilum of the spleen, and the gastrosplenic ligament
gular ligaments. This mesentery is exceptional in that the layers of the which passes from the hilum of the spleen to the greater curvature of the
coronary ligament are widely separated so that the liver has a bare area stomach (Fig. 14.2).
directly in contact with the diaphragm (the obliterated umbilical artery • The mesentery of the small intestine is attached to the posterior ab-
in the free edge of the falciform ligament and numerous small veins in dominal wall from the duodenojejunal flexure to the ileocolic junction.
the bare area, p. 35). (2) The lesser omentum (already described). • The sigmoid mesocolon passes from a V-shaped attachment on the
• The small intestine (Fig. 14.1): (1) The mesentery of the small intes- posterior abdominal wall to the sigmoid colon.
tine (the superior mesenteric artery and its branches). • The general peritoneal cavity comprises the main cavityathe greater
• The sigmoid colon: (1) The sigmoid mesocolon (the sigmoid arteries sacaand a diverticulum from itathe omental bursa (lesser sac). The
and their branches). omental bursa lies between the stomach and the stomach bed to allow
free movement of the stomach. It lies behind the stomach, the lesser
The peritoneal cavity (Figs 14.1 and 14.2) omentum and the caudate lobe of the liver and in front of the structures
• The complications of the peritoneal cavity may best be described by of the stomach bed. The left border is formed by the hilum of the spleen
starting at the transverse mesocolon. Its two layers are attached to the and the lienorenal and gastrosplenic ligaments.
anterior surface of the pancreas, the second part of the duodenum and • The communication between the greater and lesser sacs is the epi-
the front of the left kidney. They envelop the transverse colon and con- ploic foramen ( foramen of Winslow). It lies behind the free border of
tinue downwards to form the posterior two layers of the greater omen- the lesser omentum and its contained structures, below the caudate pro-
tum, which hangs down over the coils of the small intestine. They then cess of the liver, in front of the inferior vena cava and above the first
turn back on themselves to form the anterior two layers of the omentum part of the duodenum.
and these reach the greater curvature of the stomach. The four layers of • The subphrenic spaces are part of the greater sac that lies between the
the omentum are fused and impregnated with fat. The greater omentum diaphragm and the upper surface of the liver. There are right and left
plays an important role in limiting the spread of infection in the peri- spaces, separated by the falciform ligament.
toneal cavity. • In the pelvis the parietal peritoneum covers the upper two-thirds of
• From its attachment to the pancreas, the lower layer of the transverse the rectum whence it is reflected, in the female, onto the posterior
mesocolon turns downwards to become the parietal peritoneum of the fornix of the vagina and the back of the uterus to form the recto-uterine
posterior abdominal wall from which it is reflected to form the mesen- pouch (pouch of Douglas). In the male it passes onto the back of the
tery of the small intestine and the sigmoid mesocolon. bladder to form the rectovesical pouch.
• The upper layer of the transverse mesocolon passes upwards to form
the parietal peritoneum of the posterior abdominal wall, covering the The anterior abdominal wall
upper part of the pancreas, the left kidney and its suprarenal, the aorta • The peritoneum of the deep surface of the anterior abdominal wall
and the origin of the coeliac artery (the ‘stomach bed’). It thus forms the shows a central ridge from the apex of the bladder to the umbilicus pro-
posterior wall of the omental bursa. It then covers the diaphragm and duced by the median umbilical ligament. This is the remains of the
continues onto the anterior abdominal wall. embryonic urachus. Two medial umbilical ligaments converge to the
• From the diaphragm and anterior abdominal wall it is reflected onto umbilicus from the pelvis. They represent the obliterated umbilical
the liver to form its ‘mesentery’ in the form of the two layers of the fal- arteries of the fetus. The ligamentum teres is a fibrous band in the free
ciform ligament. At the liver, the left layer of the falciform ligament margin of the falciform ligament. It represents the obliterated left
folds back on itself to form the sharp edge of the left triangular liga- umbilical vein.

The peritoneum 37