1272 



THE UKO-GENITAL SYSTEM. 



The urethra, or canal by which the urine reaches the surface, leads from the 

 bladder, its aperture lying in the median plane, not far from the openings of the 

 ureters, but on a lower and anterior plane. The size and shape of the bladder, 

 the thickness of its wall, and also to a great extent its relations, vary with the 

 amount of distension, or contraction, of the organ. When the bladder is empty, 

 or only slightly distended, it lies within the pelvis minor; as it becomes filled 

 with urine it rises above the pubis, and crossing the pelvic brim, enters the 



Inferior 

 epigastric artery 



Superior peritoneal lig. 



of bladder 



Urinary bladder 



Sacro-genital fold 



Recto-vesical pouch 



Ductus deferens 



Retro-pubic pad of fat 



Prostatic urethra 



Dorsal vein of penis 



Corpus cavernosum penis 



Corpus cavernosum 



urethrae 



Anal canal 

 j Membranous urethra 

 Bulb of urethra 



Cavernous portion of urethra 

 Fm. 989. MEDIAN SECTION THROUGH THE PELVIS OF AN ADULT MALE SUBJECT. 



The urinary bladder is empty and firmly contracted. The coils of small intestine have been removed to afford 



a view of the side wall of the pelvic cavity. 



abdominal cavity. These changes affect chiefly the upper part of the bladder, which 

 becomes altered in shape and size, and acquires new connexions and relations ; the 

 lower portion varies but slightly with the amount of distension of the organ (see 

 Figs. 989 and 990). The upper part of the bladder is covered with peritoneum, which 

 is reflected on to it from the anterior abdominal wall in front, from the sides of the 

 pelvis laterally, and, in the male, across the seminal vesicles and terminal parts of 

 the ductus deferentes from the rectum behind. In the female the peritoneum passes 

 on to the bladder posteriorly from the anterior surface of the uterus. The 

 peritoneum dips down posteriorly for a certain distance between the bladder and 



