THE SPERMATIC DUCTS. 



1955 



wall by going through the internal abdominal ring. After emerging from the latter 

 it parts company with the spermatic vessels, hooks over the external and posterior 

 surface of the deep epigastric artery, crosses obliquely the external iliac vessels and 

 the pelvic brim, and enters the true pelvis. From its entrance at the internal ring 

 the vas lies within the subserous tissue immediately beneath the peritoneum, through 

 which it may usually be traced. 



During its further course (pars pelvina) the duct at first lies along the lateral 

 pelvic wall, directed backward and slightly upward towards the ischial spine, crossing 

 to their inner or median side the obliterated hypogastric artery, the obturator nerve 

 and vessels, the vesical vessels, and the ureter. After passing in front and to the 

 inner side of the ureter, the duct turns sharply downward and inward and traverses 

 the subperitoneal tissue covering the pelvic floor to reach the vicinity of the seminal 

 vesicle in the space between the posterior surface of the bladder and the rectum. 



Where in relation with the seminal vesicle, the vas deferens presents a somewhat 

 flattened spindle-form enlargement, known as the ampulla (ampulla ductus deferen- 

 tis), from 3-4 cm. in length and from 7-10 mm. in its greatest width, that passes in 

 front and then along 



the median side of the FlG - l66 3- 



seminal vesicle in its 

 descent to the pros- 

 tate gland. The con- 

 tour of the ampulla is 

 uneven and humpy, 

 especially after re- 

 moval of the invest- 

 ing fibrous tissue, due 

 to the sacculations 

 and tortuosity of the 

 canal (Fig. 1666) and 

 the short diverticula 

 that pass off from the 

 main duct at various 

 angles, thus antici- 

 patingin simplerform 

 the arrangement seen 

 in the seminal vesicle. 

 Just before reach- 











 ' 



Circular muscle 



-Longitudinal 

 muscle 



Cross-section of ampulla of spermatic duct. X 18. 



ing the latter the vas 

 usually describes a 



curve directed backward and outward (Fig. 1469) and occupies the crescentic recto- 

 vesical (sacro-genital) peritoneal fold. At the lower end of the ampulla the vas loses 

 its sacculations and again becomes a narrow tube which, joining with the passage 

 from the seminal vesicle, is continued as the ejaculatory duct that traverses the sub- 

 stance of the prostate gland and terminates in the urethra at the side of the pros- 

 tatic utricle. The ampullae of the two sides converge as they descend, so that their 

 lower ends are almost in contact where the spermatic duct receives the seminal vesi- 

 cles. The intimacy of the relation between the vasa deferentia and the bladder 

 varies with the condition of the latter organ. With the increased volume incident to 

 its distention, the posterior surface of the bladder is pressed against the spermatic 

 ducts; on the other hand, when the bladder is empty, only the lower parts of these 

 structures are in close relation with the vesical wall. 



The ejaculatory duct (ductus ejaculatorius), the terminal segment of the 

 spermatic canal and apparently formed by the union of the duct of the corresponding 

 seminal vesicle and the vas deferens, is really the morphological continuation of the 

 latter, from which the seminal vesicle is developed as a secondary outgrowth. Be- 

 ginning with a diameter of from 1.52 mm., the ejaculatory duct enters the posterior 

 surface of the prostate (Fig. 1680), defining the lower limit of the middle lobe, and 

 after a course from 18-20 mm. (about ^ in.) in length, ends in the urethra by a 

 minute elliptical opening situated on the crest at the side of the orifice of the prostatic 



