592 



ABDOMEN 



relation to the bladder, but to the entire bladder, with the 

 reflection, being pushed upwards and forwards by the ex- 

 panding gut. 



In the new-born infant the bladder differs both in form 

 and position from the bladder of the adult. It is more or 

 less pyriform, the narrow end passing into the urethra, and 

 there is little or no appearance of a basal portion (Fig. 237). 

 Further, it is placed very much higher. The internal urethral 

 orifice is at the level of the upper border of the symphysis 

 pubis, and the anterior surface of the organ is uncovered by 

 peritoneum, and lies in direct contact with the abdominal wall 

 (Symington). As growth goes on the urethral orifice sinks 

 rapidly from the period of birth up to the fourth year, and 



Reflection of peri- 

 toneum from 

 bladder to anterior 

 wall of abdomen 



Bladder ^S^^SS^WW^^l Recto-vesical 



- peritoneal 

 reflection 



Bulb of the urethra 



Sphincter ani 

 externus 



Sphincter ani 

 externus 



FIG. 237. Medial section through Pelvis of a newly-born full-time 

 Male Infant. 



R. Rectum. 



Sa. Sacrum. 



S. Symphysis pubis. 



more slowly from that period up to the beginning of the 

 ninth year. Then it remains stationary till puberty, after 

 which it sinks slowly till it attains its normal adult position 

 (Disse). It should also be noted that the recto-vesical re- 

 flection of peritoneum, in the infant at birth, is at the level of 

 the base of the prostate. 



Ureters. Having crossed the lower end of the common 

 iliac artery, or the upper end of the external iliac artery, at the 

 brim of the small pelvis, the ureter descends, along the front of 

 the hypogastric artery and its anterior division, till the level 

 of the visceral layer of the pelvic fascia is reached, i.e. the 

 level of the spine of the ischium. It then turns medially and 

 forwards on the upper surface of the visceral fascia. In this 

 part of its course it passes deep to the deferent duct, pierces 

 the vesical layer of the visceral fascia, and enters the bladder 



