THE PERITONEUM. 981 



or fourth of the posterior wall of the vagina and then upon the uterus, covering 

 its posterior wall, its fundus. its anterior surface, but it does not pass on to 

 the vagina in front. About the level of the internal os it passes over the summit 

 of the bladder as far as the urachus. The deep pouch behind the uterus and 

 vagina is called the recto-vaginal pouch, or cul-de-sac of Douglas, or recto-uterine 

 pouch. The more shallow anterior pouch is the vesico-uterine. In the male the 

 peritoneum passes from the rectum directly upon the posterior wall and summit 

 of the bladder to the urachus, forming behind the recto-vesical pouch. In either 

 sex the peritoneum passes directly from the bladder to the anterior abdominal wall 

 and does not cover the bladder anteriorly. The surgeon makes use of this fact in 

 operating upon the bladder through this space below the peritoneum and above 

 the symphysis pubis. It is called the pre-vesical space of Retzius, and is much 

 increased in size by distending the bladder. By putting 420 c.c. of fluid into 

 a rubber bag in the rectum and 500 c.c. into the bladder, the rectum will so 

 push up the bladder and the bladder will so push up the peritoneum that a space of 

 8.5 cm. will exist between the lowest fold of peritoneum and the symphysis pubis. 



This parietal layer is then simply traced, lining the anterior abdominal wall 

 around to our starting-point between the liver and diaphragm. We see then that 

 this is a closed sac and the parietal layer is continuous with the visceral. This is 

 the cavity of the greater peritoneal sac. 



We have not yet brought the peritoneum into contact with the Spigelian lobe 

 of the liver or the posterior surface of the stomach or internal surface of the 

 spleen. Behind the upper part of the large cavity and running into its lower 

 part is another artificial cavity which we have not traced, viz. the cavity of the 

 lesser sa \ or the bursa omentalis. We have seen that these two sacs are. con- 

 tinuous with each other through the foramen of Winslow. That is best shown in 

 a cross section, but is indicated in the diagram. 



The boundaries of the lesser sac cannot be well seen at this stage, and for the 

 present must be mostly studied by diagram till the anterior parts are dissected. 

 Remember the diagram is only true for the median line or near it, and nowhere 

 else but in the region of the Spigelian lobe of the liver does the lesser sac reach 

 up behind it as here represented. Imagine the hand introduced through the 

 foramen of Winslow from right to left into the lesser sac ; push the finger up 

 behind the liver and in front of the diaphragm till stopped by the fornix made by 

 the transition of parietal to visceral layer. This layer invests the Spigelian lobe 

 only behind and inferiorly till the transverse fissure is reached ; it then descends, 

 as did the layer of greater sac in front of it. to the lesser curvature of the stomach 

 forming the posterior layer of the lesser omentuin. Next it descends behind the 

 stomach and in front of the transverse colon into the great omentum, passing 

 nearly to the free border of that apron. It now turns and ascends and covers 

 the upper surface of the transverse colon and goes back to the vertebral column, 

 forming the superior layer of the transverse mesocolon. It now covers the ante- 

 rior surface of the pancreas, next the vertebral column and crura of diaphragm 

 and great vessels to the reflection on to the liver. 



It is advised that the above tracings for both sacs be followed in Fig. 607. 

 which represents the organs in greater detail. This diagram shows two sections 

 of the duodenum, one in its first and one in its second portion. A median sec- 

 tion would show its third portion about at the root of the mesentery (Fig. 606). 



We have traced the layers singly, and some new features may be presented 

 if we take two layers together, beginning above at the liver. 



Anteriorly, a layer passes back under the diaphragm and from behind another 

 approaches it ; one is from the greater sac and the other from the lesser (if sec- 

 tion be near median line). They both turn down upon the liver, making these 

 the anterior and posterior layers of the coronari/ ligament, including between 

 them a small surface of liver directly connected to the diaphragm and uncovered 

 by peritoneum. These two layers then surround the liver, forming its serous 

 coat, and meet again at the transverse fissure. The two now descend to the 



