226 SURGICAL ANATOMY OF 



ceedings upon these viscera, without danger of wounding 

 it. The space beneath the membrane varies considerably 

 in different parts of the floor of the pelvis : thus, in front 

 and at the sides it is tolerably closely applied to the 

 underlying pelvic fascia, leaving, however, a considerable 

 interspace in front of the bladder, the point selected for 

 puncturing that viscus above the pubis. Behind, and 

 above the anal region, there is a considerable interval, 

 containing a great deal of loose cellular tissue, which 

 allows of the distension of the rectum, and of the inter- 

 nal iliac vessels and their branches, the ureters, sacral, 

 sympathetic and hypogastric plexuses, and the origin of 

 the pyriformis muscle. 



SURGICAL ANATOMY OF THE BLADDER. 



The bladder is situated in the mesial line, beneath the 

 pelvic fascia and peritoneum, and lies obliquely from 

 above downwards. Being attached to the pelvic floor 

 by its body and base only, it is freely movable, but the 

 urachus and anterior reflexion of the peritoneum limit 

 its mobility posteriorly. When empty, the bladder lies 

 deep in the pelvis as a flattened sac, with its apex reach- 

 ing up to the symphysis pubis, but when distended, its 

 relations are considerably altered, and are of great sur- 

 gical importance. When moderately full, it is round and 

 partially fills the true pelvis, but when greatly distended 

 it rises up into the abdomen, perhaps even reaching to 

 the umbilicus, and becomes curved forwards. 



In children, as has been before stated, it is rather an 

 abdominal than a pelvic viscus, and is conical in shape, 

 owing to the position of the but recently obliterated 

 urachus. 



