128 THE URINARY BLADDER. 



branous structure, which occupies the anterior part of the cavity 

 of the pelvis, immediately within the ossa pubis. 



The size of the bladder is in a continued state of variation, 

 according to the quantity of urine secreted. When moderately 

 distended, it is of an irregular oval form, but rather more flat at 

 its lower extremity than above. It varies in form according to the 

 different circumstances of the pelvis to which it has been subjected. 



It is fixed firmly and immpvably to the pelvis immediately 

 within the symphysis pubis; so that it is always to be found 

 there of a larger or smaller size. This fixture is produced by 

 the attachment of the lower portion of the fundus of the bladder 

 to the parts beneath it, but principally by the anterior ligaments 

 of the bladder which proceed one on each side from the lateral 

 surfaces of the prostate gland, and are inserted into the pubis 

 of the corresponding side at the lower part of the symphysis. 

 These ligaments are in fact the extension of a membrane, 

 (called by the French anatomists, the pelvic aponeurosis,) 

 which proceeds from the upper part of the pelvis to the 

 side of the prostate gland and bladder, and which may be 

 seen by turning off the peritoneum from the levator ani 

 muscle.* It is sometimes completely empty, and occupies 

 no more space than the thickness of its coats requires. When 

 moderately distended, it occupies a considerable portion of the 

 pelvis : when distention increases, it presses the parts posterior 

 to it against the sacrum, and extends itself above the brim of 

 the pelvis into the general cavity, rising not only to the umbili- 

 cus, but in some cases to the epigastric region. 



In males the relative situation of the bladder and rectum is 

 such, that the upper and middle part of the rectum is behind 

 the bladder ; but the lower part of the rectum, following the 

 curve of the os sacrum and coccygis, is below the posterior 

 part of the bladder. 



In females the vagina and uterus are situated between the 

 bladder and rectum ; so that the connexion of these last men- 

 tioned parts is very different in the two sexes. 



* See Thesis on Femoral Hernia, &c., by Gilbert Breschet. Paris, April, 

 1819. Colics' Surgical Anatomy, Dublin, 1811, for a more minute account of 

 this membrane. H. 



