588 ABDOMEN 



orifice which separates it from the lower end of the fundus. 

 This border is separated from the back of the symphysis and 

 the pubo-prostatic ligaments by the retro-pubic pad of fat, 

 which appears in medial sections of the pelvis as a small wedge- 

 shaped mass of soft, fatty areolar tissue (Fig. 235). This pad 

 is continuous with other parts of the extra-peritoneal fat, and 

 adapts itself to the changing conditions of the bladder. 



The internal urethral orifice, by which the urine leaves the 

 bladder, is placed at the junction of the fundus with the 

 anterior border, and occupies the most dependent position. 

 It is surrounded by the base of the prostate which presents 



Ureter 

 Ductus 

 deferens 



Seminal XW\\ N Urachus 



vesicle 



Prostate ^b^aH I nfero-lateral surface 



-Membranous urethra 



FIG. 234. Bladder hardened in situ viewed from the right side. It 

 contained a slightly larger amount of fluid than the specimen depicted in 

 Fig. 232. (A. F. Dixon.) 



a structural continuity with the bladder wall. The term neck 

 is frequently applied to this region of the bladder. 



Changes in the form of the Bladder as it becomes filled 

 with Urine. The neck of the bladder is firmly fixed in 

 position by its attachment to the prostate and by its connec- 

 tion with the diaphragmatic layer of the pelvic fascia, and the 

 prostate is securely held in place by its strong sheath of pelvic 

 fascia ; therefore, as the bladder becomes filled, the internal 

 urethral orifice suffers very little change of position. It is 

 only in cases of excessive distension that any marked change 

 in its level becomes manifest, and under such circumstances 

 the internal urethral orifice sinks, to a certain extent, in 

 the pelvic cavity. 



