URINARY BLADDER. 387 



to the anal passage. This part of the bowel is supported by the 

 triangular ligament of the urethra, and by the levatores ani and 

 external sphincter muscles. 



In front of this part are the prostate, the membranous part of the relations 

 urethra, and the bulb of the corpus spongiosum urethree. The armindT^ 

 levatores ani muscles descend on its sides, and unite beneath it, 

 supporting it as in a sling. Sometimes the lower half of the rectum sometimes 

 is very much enlarged, especially in women and old men ; and in SJJSjJd. 

 that condition in the male it rises up on each side of the prostate. 



The anal passage or canal (Symington) leads downwards and Anal canal, 

 backwards from the lower end of the rectum to the anal opening. 

 Its length varies from half an inch to one inch, being shorter when 

 the bowel is distended. It is surrounded by the internal and 

 external sphincter muscles, and is compressed laterally in the 

 intervals between defsecation, so that its side-walls are in contact, 

 and the lumen has the form of a median slit. 



The URINARY BLADDER (vesica urinaria ; figs. 144 and 145, a) Bladder is 

 is the receptacle for the urine, and is situate in the fore part of the 

 pelvis. 



When the bladder is contracted it is flattened, and of a triangular 

 form, and lies against the anterior wall of the pelvis ; but when 

 distended it becomes rather egg-shaped, with the larger part and projects 

 towards the rectum, and the apex to the abdominal wall. In }J{j when 

 distension during life it is slightly curved forwards over the pubic 

 bones, and projects above them ; and if its axis were prolonged Axis, 

 forwards and backwards, it would touch the abdominal wall a variable 

 distance (according to the distension) above the pubic symphysis 

 in front, and the lower end of the sacrum behind. 



The position and form of the bladder are not the same in Position in 

 early life as in the adult. In the new-born child it rises much the cllild > 

 above the brim of the pelvis into the hypogastric region of the 

 abdomen, and has little or 110 basal surface, simply tapering down 

 to the urethral orifice which is the lowest part and is opposite the 

 upper border of the symphysis pubic (Symington). During early 

 years the bladder rapidly sinks, but it is only after puberty that 

 its final position is attained. At all times its anterior surface is 

 uncovered by peritoneum. 



In the adult the bladder is for the most part contained within in the adult, 

 the space enclosed by the pelvic bones, and the base projects 

 backwards. 



Form. In the empty condition the bladder is somewhat flattened Form, 

 from above downwards, and triangular in outline, presenting an 

 upper surface with a posterior border and two lateral borders 

 converging in front at the apex or summit, a basal surface 

 opposed to the rectum, and an anterior surface opposed to the pul)ic 

 symphysis. 



The organ is maintained in position by the recto-vesical fascia 

 and the peritoneum, as already described (pp. 378 and 384). 

 The relations of the moderately full bladder are as follows : 



The summit or apex is rounded, and from it three ligamentous A P ex has 



three cords 

 C 2 from it. 



