1908 



HUMAN ANATOMY. 



Uterus 



Uiachus 



Bladdet 



Symphysis pubis 



Urethra 



tions with the seminal vesicles and ducts. The condition of the rectum markedly influences the 

 degree to which the distending bladder rises above the symphysis, since, when the bowel is empty, 

 and hence more intrapelvic space is available, the bladder gains a lower suprapubic level than 

 when its ascent is favored by a distended rectum. With the elevation of the vesical apex above 

 the level of the symphysis, the bladder acquires a temporary relation with the anterior abdominal 

 wall in front, and its sides, in case of marked distention, may come nearly or actually into con- 

 tact with the vasa deferentia, the obliterated hypogastric arteries, and the obturator vessels and 

 nerves, as these structures lie along the pelvic wall embedded within the fat-laden subperitoneal 

 tissue. 



The bladder in the female lies lower within the pelvis than in the male, chiefly in conse- 

 quence of the absence of the prostate, and when empty never quite reaches the level of the upper 

 border of the symphysis. When distended, therefore, it less often rises into the abdomen, 

 since the capacity of the normal organ in the female is somewhat less than in the male. The 

 fundus, or postero-inferior surface, is firmly united by connective tissue with the anterior vaginal 

 wall and sometimes the lower part of the uterus. Where reflected from the anterior surface of 

 the uterus onto the bladder, the peritoneum lines the shallow utero-vesical fossa and then con- 

 tinues over the superior vesical surface. Upon the latter rests the body of the uterus, rising or 

 falling with the expansion or contraction of the bladder-wall, but normally remaining in contact, 



— a relation predisposing to the production 

 Fig. 1623. of the concave or sunken condition of the su- 



R^'^'"'" perior surface not infrequently seen in frozen 



sections of the female pelvis. 



The infantile bladder differs both in form 

 and position from the adult organ. Since 

 the greater part of the bladder represents a 

 persistent and dilated portion of the intra- 

 embryonic segment of the allantois, its fcetal 

 form is essentially tubular. In the new-born 

 child (Fig. 1623), in both sexes alike, the 

 bladder is spindle-shaped and extends from 

 about midway between the umbilicus and 

 the symphysis to the level of the pelvic brim, 

 its anterior surface being in contact with the 

 abdominal wall. Only the lower pole of the 

 infantile bladder, corresponding to the ure- 

 thral orifice, lies slightly below the upper 

 border of the symphysis, the body lying 

 entirely within the abdomen, lateral and 

 posterior surfaces being undifferentiated. 

 Leaving the anterior abdominal wall, the 

 peritoneum completely invests the posterior 

 surface of the bladder, as well as the semi- 

 nal vesicles and the ampullae of the seminal 

 ducts, before passing onto the rectum. The 

 bottom of the recto-vesical fossa lies often below the le\el of the urethral orifice, which does not 

 come into relation with the pelvic floor. In the new-born female child the uterus is situated rela- 

 tively high and comes into contact with the bladder, while the vagina does not, only touching 

 the urethra. The reflection of the peritoneum to form the utero-vesical fossa varies in position, 

 and when high, as it often is, may leave a part of the young bladder unprovided with a serous 

 covering. Coincident with the descent of the bladder, associated with the growth and expansion 

 of the pelvis, its posterior wall increases more rapidly than the anterior, this inequality resulting 

 in the production of a fundus that gradually approaches the pelvic floor. According to Disse,^ 

 the descent of the young bladder is rapid during the first three years, slower from the fourth 

 to the ninth year, between which and puberty little change occurs. Succeeding this period of 

 rest the bladder renews its descent, and by the twenty-first year has gained its definite position 

 on the pelvic floor. Before the third year the empty bladder always remains above the symphy- 

 sis ; by the ninth year it has sunken below that level, but when distended the apex rises within 

 the abdomen. During descent the non-peritoneal area on the posterior surface progressively 

 increases, the serous investment in general extending farther downward in the male than in the 

 female child. Persistence of infantile relations often accounts for variations observed in the adult. 



Structure. — The bladder consists essentially of a muscular sac lined with mucous 

 membrane and covered on its upper surface with peritoneum, a layer of connective tis- 

 sue loosely uniting the mucous and muscular coats. From within outward, four coats 



' Anatomische Hefte, Bd. i., 1892. 



Vagina 



Sagittal section lhrou:n-h pelvis of new-born female child, 



hardened in formalin, showing infantile form 



and suprapubic position of bladder. 



