THE URINARY BLADDER 1363 



hinder part of the lateral surface obliquely, and passes between the ureter and the 

 bladder. When the bladder is empty the peritoneum descends on the pelvic 

 wall as low as the lateral border of the bladder and enters a groove known as the 

 paravesical fossa. The lateral surfaces, the pubic surface, and the abdominal 

 surface together constitute the body of the bladder (corpus vesicae). 



The fundus or base (fundus vesicae) (Figs. 1111 and 1135) is directed downward 

 and backward, and is partly covered by peritoneum. In the male the upper por- 

 tion, to within about an inch and a half of the prostate, is covered by the recto- 

 vesical pouch of peritoneum (Fig. 982). The lower part is in direct contact with 

 the anterior wall of the second part of the rectum, the seminal vesicles, and the 

 vasa deferentia (Figs. 1111 and 1118). The ureters enter the bladder at the upper 

 part of its base, about an inch and a half above the base of the prostate gland 

 (Fig. 1111). 



The portion of the bladder in relation with the rectum corresponds to a tri- 

 angular space, bounded below, by the prostate gland; above, by the rectovesical 

 fold of the peritoneum; and on each side, by the seminal vesicles and the vas 

 deferens. It is separated from direct contact with the rectum by the rectovesical 

 fascia. When the bladder is very full, the peritoneal fold is raised with it, and the 

 distance between its reflection and the anus is about four inches; but this distance 

 is much diminished when the bladder is empty and contracted. In the female, 

 the base of the bladder is connected to the anterior aspect of the cervix uteri 

 by areolar tissue, and is adherent to the anterior wall of the vagina (Fig. 980). 

 Its upper surface is separated from the anterior surface of the body of the uterus 

 by the uterovesical pouch of the peritoneum (Fig. 980). 



The so-called neck or cervix of the bladder (collum vesicae) is the point of com- 

 mencement of the urethra; there is, however, no tapering part, which would 

 constitute a true neck, but the bladder suddenly contracts to the opening of the 

 urethra (Fig. 339). In the male it is surrounded by the prostate gland and its 

 direction is oblique when the individual is in the erect posture (Figs. 339 and 

 1111). In the female its direction is obliquely downward and forward. The 

 so-called neck is the most fixed portion of the bladder, and is located one inch 

 (2.5 cm.) behind the junction of the inferior and middle thirds of the symphysis 

 pubis; or two inches (5 cm.) behind and below the superior border of the sym- 

 physis. 



The summit or apex (vertex vesicae) is the portion of the bladder which when 

 that organ is empty or nearly empty is nearest to the upper border of the symphysis. 

 It is directed upward and forward. In a distended bladder the apex is well above 

 the pubes in the abdominal cavity. 



The urachus or middle umbilical ligament (ligamentum umbilicale medium } 

 (Fig. 978) is the impervious remains of the tubular canal of the allantois, which 

 existed in the embryo, and a portion of which expanded to form the bladder. 

 It passes upward, from the apex of the bladder, between the transversalis fascia 

 and peritoneum, to the umbilicus, becoming thinner as it ascends. It is composed 

 of fibrous tissue, mixed with plain muscle fibres. 



The urachus causes the formation of a peritoneal fold, the plica umbilicalis media (Fig. 978). 

 On each side of it is placed a fibrous cord, the impervious portion of the hypogastric artery, 

 which, passing upward from the side of the bladder, approaches the urachus above its summit. 

 Over each cord is the fold known as the plica umbilicalis lateralis (Fig. 978). In the infant, at 

 birth, the urachus is occasionally found pervious, so that the urine escapes at the umbilicus, and 

 calculi have been found in its canal. 



Ligaments. The bladder is retained in its place by ligaments, which are divided 

 into true and false. The true ligaments are five in number two anterior, two 

 lateral, and the urachus. The false ligaments, also five in number, consist of 

 folds of the peritoneum. 



