488 ABDOMEN 



as in the male, and, between them, the vagina. In that way 

 the floor of the pelvis, in the female, is rendered relatively weak 

 and less capable of resisting strain, whilst at the same time it is 

 adapted to the function of child-bearing, for it is cleft by the 

 vaginal canal into two segments an anterior, including the 

 anterior vaginal wall and all the parts in front of it, and a 

 posterior, formed by the posterior vaginal wall and the parts 

 behind it. The former can be lifted into the pelvis and the 

 latter can be forced downwards, much as the two segments 

 of a folding door are displaced in opposite directions, and 

 thus a passage is made for the exit of the child (Berry Hart). 

 The dissector should note also, as a matter of clinical im- 

 portance, that, whilst the urethra and the anterior wall of the 

 vagina are closely bound together and cannot be separated, 

 except by the use of the knife, the posterior wall of the vagina 

 and the anterior wall of the rectum are only loosely united 

 together, and can easily be torn apart. 



Vesica Urinaria. The urinary bladder, in the female, has 

 normally a smaller capacity, and it lies at a somewhat lower 

 level in the pelvis than the male bladder ; but its shape when 

 empty and slightly contracted is the same as in the male, i.e., 

 it has the form of a three-sided pyramid, possessing a superior 

 surface, two infero-lateral surfaces, a fundus or base, and an 

 apex. The superior surface is covered with peritoneum. It 

 is bounded by two lateral borders, which separate it from 

 the infero-lateral surfaces, and by a posterior border, which 

 separates it from the base. The two lateral borders converge 

 anteriorly and meet at the apex, from which a fibrous cord, 

 the middle umbilical ligament or urachus, passes up the 

 posterior surface of the anterior abdominal wall to the 

 umbilicus. The urachus is the remains of part of the cloaca 

 of the foetus. The lateral borders meet the posterior border 

 of the upper surface at the posterior angles of the bladder, 

 where the ureters enter the wall of the viscus. The infero- 

 lateral surfaces, and the anterior border, which separates them, 

 are devoid of peritoneum. They form the posterior wall of 

 the lower part of the cave of Retzius, and are separated from 

 the back of the symphysis and the pelvic surfaces of the pubic 

 bones by a layer of loose, extra-peritoneal fat. The term 

 retro-pubic pad is applied to that portion of the fatty tissue 

 which intervenes between the back of the symphysis pubis, 

 the upper surfaces of the medial pubo-vesical ligaments, and 



