THE PELVIC CAVITY 



413 



pectineal lines and the sacro-sciatic ligaments. The ventral wall or floor is formed 

 by the pubic and ischial bones. The boundary of the outlet is formed by the third 

 coccygeal vertebra dorsally, the ischial arch ventrally, and the posterior edges 

 of the sacro-sciatic ligaments and the semi- 

 membranosus muscles laterally. The out- 

 let is closed by the perineal fascia ; this con- 

 sists of superficial and deep layers which 

 are attached around the margin of the outlet 

 and centrally to the organs at the outlet— 

 the anus and its muscles, the vulva (in the 

 female), and the root of the penis (in the 

 male) . 



The cavity contains the rectum, parts 

 of the internal genital and urinary organs, 

 some fcetal remnants, muscles, vessels, and 

 nerves. It is lined by the fascia pelvis, and 

 in part by the peritoneum. 



The pelvic peritoneum is continuous in 

 front with that of the abdomen. It lines the 

 cavity for a variable distance backward, and 

 is then reflected on to the viscera, and from 

 one organ to another. We may therefore distinguish an anterior, peritoneal, and a 

 posterior, retroperitoneal, part of the cavity. Along the middorsal line it forms 

 a continuation of the colic mesentery, the mesorectum, which attaches the first or 

 peritoneal part of the rectum to the roof. In animals in fair condition a consider- 



FiG. 351. — Diagram or Sagittal Section of 

 Male PELvia to show Disposition of 

 Peritoneum. 

 a, Sacro-rectal pouch, continuous laterally with 



b, reoto-genital pouch: c, vesico-genital pouch; d, 



vesico-pubic pouch. The lateral line of reflection 



of the peritoneum is dotted. 



Fig. .352. — Schematic Cross-section to Show Ar- Fig. 353. — Schematic Cross-section to Show Ar- 



R.ANGEMENT OF PeLVIC PeRITONEUM IN THE MaLE. RANGEMENT OF PeLVIC PeRITONEUM IN THE FeMALE. 



a, b, Recto-genital pouch; c, c, vesico-genital pouch; d, d, vcsico-pubic pouch; 1, mesorectum; 2, 2, genital folds 

 in male, broad ligaments of uterus in female; 3, 3, lateral ligaments of bladder; 4, middle ligament of bladder; v.d., 

 ductus deferentes; u.m., uterus mascuUnus. 



able quantity of subserous and retroperitoneal fat is found on the walls and in the 

 various interstices. 



In the male the general disposition of the peritoneum here is as follows. If 

 traced along the dorsal wall, it is reflected from the sacrum on to the rectum. 



