THE PERITONEUM 



1255 



Traced downward it covers the antero-superior surface of the stomach and the 

 commencement of the duodenum, and is carried down from the greater curvature 

 of the stomach into a large free fold, the gastrocolic or greater omentum (Figs. 980 

 and 986). Reaching the free edge of this fold, it is reflected upward to cover 

 the under and posterior surfaces of the transverse colon, and thence to the pos- 

 terior abdominal wall as the inferior layer of the transverse mesocolon (Fig. 970). 

 It reaches the abdominal wall at the upper border of the third part of the duo- 

 denum, and is then carried down on the superior mesenteric vessels to the small 

 intestine as the anterior layer of the mesentery. It encircles the intestine, and 



-LESSER OMENTUM 

 ARROW IN FORAMEN 



OF WlNSLOW 



FIG 979. Diagram showing the vertical disposition of the peritoneum Lesser sac in red; greater sac in blue 



subsequently may be traced, as the posterior layer of the mesentery, upward and 

 backward to the abdominal wall. From this it sweeps down over the aorta into 

 the pelvis, where it invests the sigmoid colon, its reduplication forming the sig- 

 moid mesocolon (Fig. 988). Leaving first the sides and then the front of the rectum, 

 it is reflected on to the base of the bladder, and, after covering the upper surface 

 of that viscus, is carried along the urachus and impervious hypogastric arteries 

 to the back of the abdominal wall, from which a start was made. 



Between the rectum and the bladder the peritoneum forms, in the male, a pouch, 

 the rectovesical pouch (excavatio rectovesicalis), bounded on the sides by two 



