1292 



THE UKO-GENITAL SYSTEM. 



Beyond the ureter the duct takes a somewhat sudden bend, and passes down- 

 wards and medially towards the median plane, beneath the peritoneum of the pelvic 

 floor. Beaching the interval between the base of the bladder in front and the 

 rectum behind, the ducts of opposite sides occupy the angle formed between the 

 vesiculse seminales (Fig. 1012). As they approach one another each duct becomes 

 somewhat tortuous, sacculated, and dilated, and assumes a general resemblance in 

 structure to a portion of the seminal vesicle. This dilated part of the ductus 

 deferens is termed the ampulla ductus deferentis. As it turns medially the duct 

 lies a short distance behind the ureter, and immediately in front of the free edge of 

 the peritoneal fold (sacro-genital) which bounds the recto-vesical or recto-genital 

 pouch of the peritoneum. Just above the base of the prostate the ductus deferens 

 becomes once more a narrow canal, and in this position it is joined by the duct 

 of the corresponding seminal vesicle to form the ductus ejaculatorius, which, after 

 a short course downwards, forwards, and medially through the prostate, opens into 

 the urethra. 



In some cases the ductus deferens crosses the obliterated umbilical artery before it enters the 

 cavity of the pelvis minor ; it normally does so in the fetus. 



Ejaculatory 

 duct 



Seminal vesicle 



A and B. Drawings illustrating the seminal vesicle and the ampulla of the ductus deferens taken from two j 



different subjects. 

 C. The seminal vesicle and ductus deferens have been cut into to show the pitted structure of their walls. 



Ductus Ejaculatorius (O.T. common ejaculatory duct). The ejaculatory d\ 

 is a very slender canal, formed by the union of the ductus deferens with th< 

 duct of the corresponding seminal vesicle. It is less than one inch in lengtl 

 and lies very close to its fellow of the opposite side as it passes through the prostat 

 behind its median lobe. The ducts open by slit-like apertures into the first part 

 the urethra, one on each side of the utriculus prostaticus. They are well seen ii 

 sections through the upper part of the prostate (Fig. 1011). 



The mucous membrane of the duct is thrown into numerous complicated folds, and ii 

 connexion with it are a number of remarkable minute diverticula, which are enck 

 within the muscular coat of the duct. 



Vesiculse Seminales. The seminal vesicles are a pair of hollow sacculat 

 structures placed in front of the rectum and behind the bladder (Fig. 1012). Eacl 

 vesicle is usually about two inches in length, and has its long axis direcl 

 downwards, medially, and somewhat forwards. The superior extremity of 

 vesicle, which is partly covered by peritoneum, is large and rounded, and lies at 

 considerable distance from the median plane, behind the inferior end of the ureter 

 The peritoneum of the recto-vesical or recto-genital pouch separates the upj 

 end of the seminal vesicle from the rectum ; below the peritoneal cavity the vesic 



