358 THE ABDOMEN AND PELVIS 



bladder and is reflected from its apex on to the anterior abdominal 

 wall. 



The Urinary Bladder occupies the anterior part of the 

 pelvic basin and lies immediately behind the pubes. When 

 empty it is somewhat pyramidal in shape, with an apex, a base, 

 a superior, and two infero-lateral surfaces. 



The apex of the bladder is directed forwards and upwards 

 and is in contact with the pubic symphysis. An impervious 

 fibrous cord, known as the urachus (p. 381), passes upwards 

 from the apex to the umbilicus in the extra-peritoneal fat. 



The base or posterior surface is directed backwards and 



,. Ureter 



___ Membranous urethra 



FIG. in. Basal aspect of Bladder, Seminal Vesicles, and Prostate, 

 hardened by formalin injection. 



slightly downwards towards the rectum. It is roughly triangular 

 in shape ; the inferior angle is truncated and corresponds to the 

 internal orifice of the urethra, while the supero-lateral angles 

 are joined by the ureters. In the middle line the two ductus 

 deferentes lie side by side in apposition with this surface and 

 separate the seminal vesicles from one another (Fig. in). These 

 parts of the genital tract are embedded in visceral pelvic fascia 

 and intervene between the basal surface of the bladder and the 

 rectum. A small interval, however, exists between the ductus 

 deferentes near the upper border, and it slightly increases in 

 size as the bladder becomes distended. Through this area the 

 trochar was passed in puncture of the bladder by the old-fashioned 

 rectal route. 



