THE PELVIS 359 



The superior surface is entirely covered by peritoneum 

 and is related to coils of small intestine or pelvic colon. Along 

 its lateral borders the peritoneum is reflected on to the pelvic 

 walls as the so-called lateral false ligaments of the bladder. 



The infero-lateral surfaces are related in front to the bodies 

 of the pubes and the retro-pubic pad of fat. Posteriorly they 

 are in contact with the upper parts of the obturator internus and 

 levator ani muscles. 



The neck of the bladder is situated where the infero-lateral 

 and posterior surfaces meet one another. It is pierced by the 

 urethra and is partly continuous with the prostate. 



When the bladder distends, it becomes more or less ovoid in 

 shape. The neck and posterior surface are not much affected 

 but the infero-lateral and superior surfaces become greatly 

 stretched, and the upper part of the bladder comes to lie in the 

 abdomen. This increase in size does not involve any stretching 

 of the vesical peritoneum, for, as the bladder rises into the 

 abdomen, it strips the peritoneum off the lateral pelvic and 

 anterior abdominal walls. In this way the anterior part of the 

 infero-lateral surfaces comes to lie in direct contact with the 

 anterior abdominal wall, no peritoneum intervening. In aspirat- 

 ing the over-distended bladder supra-pubically, the surgeon takes 

 advantage of this alteration in the disposition of the peritoneum, 

 and in the operation of supra-pubic cystotomy the same condition 

 is obtained by distending the bladder artificially. 



In the infant, the bladder occupies a higher position than it 

 does in the adult owing to the smaller relative size of the pelvis 

 and the greater relative size of the bladder itself. The internal 

 orifice of the urethra lies almost on a level with the upper border 

 of the pubic symphysis, and most of the bladder is situated in the 

 abdomen. This difference must be borne in mind when opening 

 the abdomen in the infant, and care should be taken to see that 

 the bladder is evacuated before making an incision in the lower 

 part of the anterior abdominal wall. 



The retro -pubic pad of fat occupies the space of Retzius, 

 which is bounded in front by the symphysis pubis, behind by 

 the bladder, and below by the true pubo-prostatic ligaments. 

 In extra-peritoneal rupture of the bladder the extra vasated urine 

 collects temporarily in this space (p. 378). 



Supra -Pubic Cystotomy is commonly performed for the 

 removal of calculi, tumours, and soft, enlarged prostates capable 

 of easy enucleation. The bladder is emptied, and then filled 



