Aas 
THE PERITONEUM. 1049 
liver varies according as it is traced at the right, the left, or the middle portion of the liver. It 
clothes the right portion as far back as the lower edge of the uncovered area of the liver, where 
it is reflected on to the posterior wall of the abdomen and the top of the right kidney (constitut- 
ing the hepato-renal ligament), as the lower layer of the coronary ligament. On the left portion 
it is continued back as far as the posterior border of the left lobe—or even a little way on to its 
upper surface—whence it passes to the diaphragm as the inferior layer of the left lateral 
ligament. The middle region of the under surface it clothes only as far as the portal fissure and 
the fissure of the ductus venosus ; from these the peritoneum is carried down as the anterior layer 
of the lesser omentum to the lesser curvature of the stomach, where we shall return to it directly. 
The peritoneum, which passes back on the under surface of the diaphragm to the left of the 
liver, is continued down on the posterior abdominal wall, behind the fundus of the stomach and 
the spleen, until the left kidney is reached. It covers the upper and outer part of the kidney, 
and is then carried forward as the leno-renal ligament to the spleen, around which it passes 
—clothing its renal, phrenic, and gastrie surfaces—as far as the hilus (Fig. 709); from this it 
is carried to the stomach as the anterior layer of the gastro-splenic omentum. Similarly, the 
under layer of the left lateral ligament is continued down on the back part of the diaphragm to 
the w@sophagus, the anterior and left sides of which it clothes. It also forms a little fold at the 
left of the @sophagus, known as the gastro-phrenic ligament (see p. 1007 and Fig. 710). 
At the right side, the portion of the peritoneum which forms the under layer of the 
coronary ligament is carried down over the right kidney (and lower part of the suprarenal 
capsule) to the duodenum and hepatic flexure, over both of which it passes. 
We shall now follow down the posterior layer of the great sac—which we 
have already traced to the stomach—as seen in a sagittal section (Fig. 707). 
Having reached the lesser curvature of the stomach, it passes down over the 
front of that organ, clothing it completely as far as the great curvature. From 
this it descends, in front of the transverse colon and small intestine, forming the 
anterior layer of the great omentum—a large apron-like fold, containing the lower 
part of the small sac in its interior, which hangs down from the stomach. Arrived 
at the lower border of the great omentum, the membrane returns on itself, and 
passes upwards towards the posterior abdominal wall, forming the posterior layer 
of that omentum. On the way it meets, and passes behind the transverse colon, 
clothing its posterior aspect at the same time (Fig. 707), and is then continued, 
as the posterior layer of the transverse mesocolon, up to the posterior abdominal 
wall, which it reaches at the anterior border of the pancreas (Fig. 707). 
From the anterior border of the pancreas it is continued downwards again, 
clothing first the lower part of that organ, then the front of the third portion of 
the duodenum, and below this the posterior abdominal wall. From this latter, 
however, it is soon carried forwards again by the branches of the superior mesen- 
teric vessels, passing to the small intestine. Running out along these, it forms 
the upper (or more correctly, the right) layer of the obliquely-placed mesentery 
(Fig. 707): on reaching the small bowel at the border of the mesentery, it invests 
that tube, giving it its serous coat, and then returns—as the under, or left, layer 
of the mesentery—to the posterior abdominal wall, on which it runs down, covering 
the great vessels near the middle line, and the psoas muscles and ureters at each 
side, to enter the pelvis. The mesentery 1s described at page 1020. 
Pelvic Peritoneum.—The detailed arrangement of the peritoneum in the pelvic 
cavity is somewhat complicated, and is fully described in connexion with the 
several pelvic organs. A general account will suffice here. 
Having passed over the brim all round, it enters the pelvis, and covers its 
walls as low as the pelvic floor, across which it passes to the various organs. 
Behind, it invests completely, and forms a mesentery (pelvic mesocolon) for, the 
pelvic colon, as far down as the third sacral vertebra. Here the colon joins the 
rectum proper, and the complete investment of the bowel ceases. 
As the end of the pelvic colon is approached the two layers of its mesocolon 
become shorter, and when the rectum is reached, they separate, leaving its posterior 
surface uncovered, whilst the bowel is clothed in front and at the sides. Lower 
down, the membrane leaves the sides, and finally, at a point which is usually about 
3 inches (7°5 em., see page 1039) above the anus, it leaves the front of the bowel, 
and in the male is carried on to the back part of the bladder (here covered by the 
seminal vesicles and vasa deferentia), forming the floor of the recto-vesicle pouch 
(excayatio recto-vesicalis, recto-genital pouch) found between these organs. It 
then covers the upper surface of the bladder, and passing off from its sides to the 
Bei 
