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 foetal 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 
Fie. 351—Diacram or Sacitrat Secrion oF 
Marte Petyis To sHOW DISPOSITION OF 
PERITONEUM. 
a, Sacro-rectal pouch, continuous laterally with 
6, recto-genital pouch; c, vesico-genital pouch; d, 
vesico-pubic pouch. The lateral line of reflection 
of the peritoneum is dotted. 
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 mid-dorsal 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- 
Fic. 353—Scuematic Cross-section To SHow ArR- 
RANGEMENT OF PeLvic PERITONEUM IN THE FEMALE. 
Fig. 352.—Scnematic Cross-section To SHow ArR- 
RANGEMENT OF PeELvic PERITONEUM IN THE MALE. 
a, b, Recto-genital pouch; c, c, vesico-genital pouch; d, d, vesico-pubie 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 masculinus. 
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 
raced along the dorsal wall, it is reflected from the sacrum on to the rectum, 
