1278 



THE UKO-GENITAL SYSTEM. 



of that canal. The ureters pierce the bladder wall very obliquely, and so the 

 minute orificium ureteris, or opening, of each has an elliptical outline. The lateral 

 boundary of each opening is formed by a thin, cresceiitic fold, which, when the 

 bladder is artificially distended in the dead subject, acts as a valve in preventing 

 water or air from entering the ureter. Hence the term " valvula ureteris " is some- 

 times used to designate the fold. In the empty bladder the urethral orifice and 

 the openings of the two ureters lie at the angles of an approximately equilateral 

 triangle, whose sides are about one inch in length. When the bladder is distended the 

 distance between the openings may be increased to one and a half inches or more. 

 Bladder in the Female. In the female the bladder is related posteriorly to 



Urethral orifice 



Folds of mucous 

 membrane 



Muscular coat 

 of bladder 



Trigonum vesicse Retro-ureteric fossa 



Torus uretericus 

 FIG. 995. EMPTY AND CONTRACTED URINARY BLADDER, OPENED UP BY THE REMOVAL OF ITS UPPER WALL. 



The peritoneum is seen spreading out from the lateral and posterior borders of the organ. Compare with 



Fig. 1000. 



the uterus and upper part of the vagina. The anterior surface of the uterus in its 

 upper part is separated from the upper surface of the bladder by the shallow utero- 

 vesical pouch of peritoneum, but the two organs are nevertheless normally in 

 apposition. So close is this relationship that the upper surface of the bladder very 

 often shows a slight concavity, due to contact with the convex anterior wall of the 

 uterus. The lower part of the uterus and upper part of the vagina are not 

 separated by peritoneum from the basal surface of the bladder, but are in actual 

 apposition with it (Fig. 996). Thus, below the level of the utero-vesical pouch, 

 the female bladder is related in much the same manner to the uterus and anterior 

 wall of the vagina as the male bladder is related to the vesiculse seminales and 

 ductus deferentes. The apex of the bladder, where the urachus is attached, often lies 

 on a lower level than in the male, so that the organ, even when distended, rises 

 less freely into the abdomen. The bladder as a whole is placed deeper in the pelvis 

 than in the male, and the internal urethral orifice lies just above, or just below, a 

 line drawn from the lower margin of the symphysis to the lower end of the sacrum 

 (p. 1274). The lower level of the internal urethral orifice is probably correlated 

 with the absence of a distinct prostate in the female. It is probable that as 

 regards capacity no difference exists between the bladder in the male and in the 

 female ; the conflicting results arrived at by different observers are probably due to the 

 faulty methods which have been employed in estimating the capacity of the organ. 



