PELVIS MINOR 413 



surface of the sacro-genital fold the peritoneum passes to 

 the front of the rectum, on which it is reflected upwards to 

 the pelvic colon. Below the line of reflection from the sacro- 

 genital fold there is a part of the rectum entirely devoid of 

 peritoneal covering. The part immediately above that is 

 covered only in front, but at a higher level the front and the 

 sides also are covered ; and when the pelvic colon is reached 

 the peritoneum entirely surrounds that part of the gut and 

 attaches it to the posterior wall of the pelvis by a fold or 

 mesentery, called the pelvic meso-colon. The hollow or pouch 

 between the sacro-genital fold in front and the rectum behind 

 is the recto-vesical or recto-genital pouch. 



The Peritoneal Fossae. : As the peritoneum follows the 

 contours of the more projecting viscera, three hollows or 

 secondary pouches are formed on each side : an anterior 

 or paravesical, a middle or genital, and a posterior or pararectal. 

 The paravesical fossa is bounded medially by the bladder, 

 laterally by the pelvic wall, and posteriorly by a ridge of 

 peritoneum, caused by the ureter, which runs backwards and 

 laterally from the postero-lateral angle of the upper surface 

 of the bladder towards the hypogastric artery. Beneath the 

 floor of the paravesical fossa the ductus deferens runs medially 

 towards the genital fossa. The genital fossa lies between the 

 ureteral ridge and the margin of the sacro-genital fold ; and 

 the pararectal fossa is between the sacro-genital fold and the 

 side of the rectum. The two pararectal fossae are continuous 

 with each other across the front of the rectum and form 

 together the recto-vesical pouch. When the rectum is dis- 

 tended the peritoneum of the pararectal fossae is lifted up to 

 cover the expanding wall of the viscus, the pararectal fossae 

 are obliterated, and the posterior ends of the sacro-genital 

 folds terminate on, or in close relation with, the wall of the 

 rectum. When the bladder is distended the middle part of 

 the sacro-genital fold is also opened out to help to cover the 

 upper part of the fundus of the bladder, but the lateral parts 

 remain. If, however, the bladder and rectum are simultane- 

 ously distended the lateral parts of the sacro-genital fold 

 pass from the back of the bladder either to the rectum 

 or to the posterior wall of the pelvis close to the rectum, 

 and under those conditions the folds in question were formerly 

 described as the recto-vesical folds or posterior false ligaments 

 of the bladder. 



