1030 THE MALE REPRODUCTIVE ORGANS 



Each vesicula is of somewhat tvian.uular form, its liroad uj^per extremity lying be- 

 neath the peritoneum, its apex joining the vas deferens at the base of the prostate. 

 It averages about two and a quarter inches (6 cm.) in length and half an inch (12 

 mm. ) in diameter at its base. It is lolnilated on the surface, and on dissection is 

 found to consist of a central tube from three to five inches (8-12 cm. ) in length, with 

 two or more short lateral liranches. It is related in front to the posterior wall of the 

 bladder, and by its upper extremity overlajts the ureter; posteriurli/ it is covered by tbe 

 recto-vesical pouch of jieritoneum, for a short distance above; and below this point it 

 lies in direct contact with the front of the rectum, and external to the ami)ulla of 

 tlie vas deferens. It becomes constricted at its junction with the vas. Structurally 

 it consists of a fibrous external coat, a middle muscular coat, and an internal mucous 

 membrane. The muscularis is arranged in tln-ee layers, the inner and outer of 

 which are longitudinal in direction, the intermediate fibres ])eing transverse. 



The mucous membrane is plicated, sacculated, yellowish-brown in colour, and 

 lined with cylindrical epithelium. It is invested, together with the ampulla of the 

 vas, by a kind of sheath of fil:)rous tissue and by a layer of smooth muscular fibres 

 which is probably accessory in function to the contractile element of the proper 

 wall of the tubes. 



The EJACULATORY DUCT, formed on each side by the union of the vas def- 

 erens and vesicula seminalis, is an infundiljuliform tube about f of an inch in 

 length, and about ^ of an inch (3 nnn.) in width above, narrowing to ^ of that 

 size below, Avhile the lumen near its opening is not more than -^ of an inch 

 (O-o mm.) in diameter. The two ducts converge slightly as they descend, and 

 finally, passing behind the so-called ' middle lobe,' the hinder part of the basal 

 muscular ring of the prostate (page 1022), pierce the prostatic fissure and open on 

 to the verumontanum on either side of the orifice of the sinus pctcularis (fig. 624). 



Vessels and Nerves of the testicle and its appendages. — The testicle is 

 supplied with blood by the spermatic and deferential arteries, the two vessels 

 anastomosing with each other and with the scrotal arteries at tliie lower extremity 

 of the gland. The corresponding veins, spermatic and deferential, form like com- 

 munications and run up in two separate groups. The spermatic veins, large and 

 imperfectly valved, spring from the upper part of the testicle, and, running in front 

 of the deferential veins around the spermatic artery, are connected to each other by 

 means of short transverse branches; finally, the right ends in the vena cava, the 

 left in the left renal vein. The lymphatics of the vas and testicle accompany 

 the veins. The former terminate in the pelvic iliac glands, the latter in the lumbar 

 glands. 



The free anastomosis between the deferential, spermatic, and scrotal blood- 

 vessels explains why the ligature or excision of the spermatic veins and artery in 

 varicocele leaves the nutrition of the testicle unimpaired; while the intercommuni- 

 cation of the testicular and scrotal blood and h^mph vessels behind the epididymis 

 accounts for the extension of inflammatory affections of the epididymis to the 

 scrotal integument. 



The Nerves of the testicle come from the aortic, renal, and hypogastric 

 plexuses. 



The vesicula seminalis is supplied by the deferential, inferior vesical, and middle 

 hfiemorrhoidal arteries : its veins, large and numerous, form a kind of plexus 

 which receives some of the vesical veins, and communicates below and in front 

 with the prostatic jilexus: its lymphatics end in the pelvic glands, and the nerves 

 are derived from the hypogastric plexus. 



SPERMATIC CORD 



The spermatic cord is the elongated pedicle of the testicle. It extends from 

 the internal inguinal ring, where its component structures are collected together, 

 through the inguinal canal, and into the scrotum as far as the summit of the 

 testicle. Its constituent elements are as follow (fig. 626). 



1. The vas deferens, lying with the deferential vessels posterior to the other 

 structures, and recognisable by its cord-like resistance to pressure. 



