12 56 THE ORGANS OF DIGESTION 



crescentic or semflunar folds (plicae rectovesicales], which pass from the posterior 

 surface of the bladder to the sides of the rectum ; the bottom of this pouch is about 

 on a level with the middle of the seminal vesicles i. e., three inches or so from 

 the orifice of the anus. When the bladder is distended the peritoneum is carried 

 up with the expanded viscus, so that a considerable part of the anterior surface 

 of the latter lies directly against the abdominal wall without the intervention of 

 the peritoneal membrane. When the bladder is empty the peritoneum forms 

 a transverse fold over its upper surface (plica vesicalis transversa). 



In the female the peritoneum is reflected from the rectum to the upper part 

 of the posterior vaginal wall, forming the recto vaginal pouch or pouch of Douglas 

 (excavatio rectouterina) (Fig. 980). It is continued over the posterior surface 

 and fundus of the uterus on to its anterior surface, which it covers as far as 

 the junction of the body and cervix uteri, forming here a second but shallower 

 depression, the uterovesical pouch (excavatio vesicouterina). It is also reflected 

 from the sides of the uterus to the lateral wall of the pelvis on each side as two 

 expanded folds, the broad ligaments of the uterus (ligamenta lata uteri), in the 

 free margin of each of which is the Fallopian tube. 



Vertical Disposition of the Lesser Sac (Fig. 979). A start may be made in this 

 case on the posterior abdominal wall above the pancreas. From this region 

 the peritoneum may be followed upward on to the inferior surface of the Dia- 

 phragm, and thence on to the Spigelian and caudate lobes of the liver to the fissure 

 for 'the ductus venosus and the transverse fissure; this cul-de-sac is the Spigelian 

 recess. Traced laterally, it is continuous over the inferior vena cava with the 

 posterior wall of the greater sac. From the liver it is carried downward to the 

 lesser curvature of the stomach as the posterior layer of the gastrohepatic omentum, 

 and is continuous on the right, around the hepatic artery, bile duct, and portal vein, 

 with the greater sac. The posterior layer of the gastrohepatic omentum is carried 

 down to the greater curvature of the stomach as a covering for the postero-inferior 

 surface of this viscus, and from the greater curvature is continued downward 

 as the deep layer of the greater or gastrocolic omentum. From the free margin 

 of this fold it is reflected upward on itself to the anterior and superior surfaces of 

 the transverse colon and thence as the superior layer of the transverse mesocolon 

 to the upper border of the third part of the duodenum, from which it may be 

 followed over the front of the pancreas to the level at which a start was made. 

 It will be seen that the loop formed by the wall of the lesser sac below the transverse 

 colon follows, and is closely applied to, the deep surface of that formed by the 

 greater sac, and that the greater omentum or large fold of peritoneum which hangs 

 in front of the small intestine therefore consists of four layers, two anterior and 

 two posterior, separated by the potential cavity of the lesser sac though inseparably 

 blended, as a rule, in the adult. 



Horizontal Disposition of the Peritoneum. Below the transverse colon the 

 arrangement is extremely simple, as it includes only the greater sac (Fig. 981); 

 above the level of the transverse colon it is more complicated on account of the 

 existence of the two sacs. Below the transverse colon it may be considered in 

 in three regions viz., in the pelvis and in the abdomen proper, upper and lower 

 portions. 



1. In the Pelvis. The peritoneum here follows closely the surfaces of the pelvic 

 viscera and the irregularities of the pelvic walls and presents important differences 

 in the two sexes: (a) In the male it encircles the sigmoid flexure, from which 

 it is reflected to the posterior wall as a fold, the sigmoid mesocolon. It then 

 leaves the sides and, finally, the front of the rectum, and is continued to the bladder; 

 on either side of the rectum it forms a fossa, the pararectal fossa, which varies in 

 size with the distention of the rectum. In front of the rectum the peritoneum 

 forms the rectovesical pouch, which is limited laterally by peritoneal folds extending 



