PELVIS 597 



embedded. When it is unravelled several blind diverticula 

 will be found to proceed from the main tube. The lower end 

 of the tube, which is called the excretory duct, emerges from 

 the pointed lower end of the vesicle and joins with the ductus 

 deferens, at an acute angle, to torm the ejaculatory duct. 



Ductus Deferens (O.T. Vas Deferens). The deferent duct, 

 or duct of the testicle, was previously traced to the abdominal 

 inguinal ring (p. 410), through which it enters the abdomen. 

 Separating itself from the other constituents of the spermatic 

 cord, it hooks round the inferior epigastric artery, -and 

 descends on the medial side of the external iliac vessels to 

 the pelvis. It then runs backwards, on the side wall of the 

 pelvis, immediately lateral to the peritoneum, through which 

 it is clearly visible, and it crosses, in turn, the umbilical artery, 

 the obturator nerve, the superior vesical artery, and the ureter. 

 Immediately beyond the ureter it turns sharply medially 

 towards the fundus of the bladder, enters the pelvic fascia, 

 comes into relation with the blunt upper end of the seminal 

 vesicle, and runs downwards and medialwards, in close apposi- 

 tion with the upper or medial side of the vesicle, to the base 

 of the bladder. There, lying close to the median plane, and 

 to its fellow of the opposite side, it turns vertically downwards 

 to the base of the prostate. The lower part of the duct is 

 dilated, tortuous, and sacculated, and is termed the ampulla, 

 but its lower end narrows greatly and joins with the duct 

 of the seminal vesicle to form the ejaculatory duct. 



Triangle on the Base of the Bladder. It is customary 

 to describe a triangle at the base of the bladder, bounded 

 laterally by the deferent ducts, and above by the reflection of 

 the peritoneum at the bottom of the recto-vesical excavation. 

 When the pelvic viscera are hardened in situ, by formalin 

 injection, such a space can hardly be said to exist, owing to 

 the approximation of the ampullae of the deferent ducts, 

 but it is possible that when the bladder is distended the 

 space between the deferent ducts may be increased. 



Dissection. The peritoneum has already been lifted up and the 

 extra- peritoneal fat removed to show the visceral branches of the hypo- 

 gastric artery. The pelvic fascia must now be removed and the remaining 

 branches of the hypogastric artery and the accompanying veins must be 

 followed, so far as they lie in the pelvis. Accompanying the arteries a number 

 of nerve twigs from the pelvic plexuses, and from the third and fourth sacral 

 nerves, should be noticed and preserved. As the dissector approaches the 

 posterior pelvic wall he must pull the rectum forwards, and as he does 

 this he should note that branches from the sympathetic cord and from the 

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