ABDOMINAL CAVITY 457 



forms three definite pouches : a median recto- vesical pouch, 

 bounded in front by the bladder and behind by the rectum 

 and laterally, on each side, by a sacro-genital fold of 

 peritoneum, which passes from the region of the fundus of 

 the bladder, past the side of the rectum, to the sacrum. 

 Each of the two lateral pouches is bounded medially by the 

 side of the bladder and the sacro-genital fold, and laterally by 

 the side wall of the pelvis. In the female the median recto- 

 vesical pouch of the male is divided, by the interposition of 

 the uterus and the upper part of the vagina, into a larger 

 posterior part, the recto-uterine pouch (pouch of Douglas), and 

 a smaller anterior part, the utero-vesical pouch ; and the broad 

 ligament which connects the lateral border of the uterus with 

 the side wall of the pelvis divides each of the single lateral 

 pouches present in the male into an anterior or paravesical 

 part, and a posterior part, the lateral pouch of Douglas, in 

 which the ovary and the termination of the oviduct are 

 situated. 



Peritoneum. The peritoneum is the great serous 

 membrane which forms the wall of the peritoneal cavity. 

 Externally it is blended with the subserous or extra-peritoneal 

 tissue of the abdomen through which the vessels and nerves 

 of the abdomen pass to their terminations. Internally it is 

 covered with a flat glistening epithelium. In the male the 

 cavity of the peritoneal sac is closed ; that is, it does not 

 communicate with the exterior of the body. In the female, 

 on the other hand, it does communicate with the exterior 

 through the female genital passages, the oviducts, the uterus, 

 and the vagina. In neither sex, however, is it an entirely 

 closed sac, for in both it is in direct communication with 

 the lymph vessels, by numerous minute openings which exist 

 on the lower surface of the diaphragm, and in other regions 

 of the wall of the sac, and it is on this account that fluids, 

 and fluid-borne micro-organisms which have gained entrance 

 into the cavity of the peritoneum, pass so readily into the 

 lymph, and thence into the general blood stream. 



When the abdomen was opened the cavity of the 

 peritoneum was also opened, and the dissector's attention 

 was drawn to the smooth and glistening appearance of the 

 inner surface of the serous membrane, which is due to the 

 lining epithelium. He must have noted, as the examination 

 of the cavity proceeded, that the peritoneum gave more or 



