TESTICLE (NORMAL ANATOMY). 



from the contracted part of the canal of the 

 epididymis at an acute angle, it ascends along 

 the inner side of this body, from which it is 

 separated by areolar tissue and the spermatic 

 arteries and veins. A right or left testicle may 

 thus always be distinguished by the circum- 

 stance that when the testicle is in position, 

 the vas deferens is situated on the inner or 

 mesial side of the organ. In this part of its 

 course, for the distance of about an inch and 

 a half, or more, the vas deferens forms numer- 

 ous convolutions, (fig*. 632., and 633, z.), 

 which gradually cease as the duct mounts 

 above the testicle. The inflected part of the 

 vas deferens, when unravelled, was found by 

 Lauth to measure six inches and a half. It 

 afterwards takes a direct course (/.) up the 

 spermatic cord to the inguinal canal, passing 

 behind anil at a short distance from the 

 spermatic arteries and veins. On entering the 

 abdomen at the internal ring, it quits the 

 spermatic vessels and descends into the pelvis, 

 passing at first by the side of, and afterwards 

 behind and below the bladder, on the inner 

 side of the corresponding vesicula seminalis, 

 the excretory duct of which it joins at an 

 acute angle, to form the ejacnlatory canal. 

 The canal of the vas deferens is extremely 

 fine, and its walls are nearly uniform in thick- 

 ness until it reaches the vesicula seminalis. 

 It is lined by a fine membrane of a mucous 

 character, which is continuous with the 

 urethra. This membrane forms longitudinal 

 folds. The vas deferens is round and in- 

 durated, harder than any other excretory 

 duct in the body, by which character it is 

 easily distinguished, when handled, from the 

 other parts constituting the spermatic cord. 

 Many anatomists have entertained the opinion 

 that the parietes of this duct are muscular. 

 It is distinctly so in the bear, bull, and other 

 animals. On careful examination, however, 

 of sections of the human vas deferens with the 

 microscope, I could discover nothing more 

 than simple fibrous tissue. Huschke makes 

 three layers of fibres ; two longitudinal, and 

 one circular, situated between them ; the 

 latter being the thickest. The duct has an 

 external investment of condensed areolar 

 tissue. 



IV. The Vessels and Nerves. Spermatic 

 Vessels. The spermatic arteries, the chief 

 vessels supplying the testicles, arise in pairs, 

 at a very acute angle, from the fore-part of 

 the aorta, immediately below the renal ar- 

 teries. Their origin is subject to consider- 

 able varieties. The two seldom arise at the 

 same level, and the right is often a branch of 

 the right renal artery. Sometimes one or 

 both come off from the superior mesenteric. 

 Occasionally there are two spermatic arteries 

 on one or both sides, arising in the regular 

 way. All these deviations are more frequently 

 met with on the left than on the right side of 

 the body. Each artery pursues a tortuous 

 course downwards and outwards, passing 

 behind the peritoneum obliquely across the 

 psoas muscle and ureter, to which, as well 

 as to the surrounding areolar tissue, it gives 



981 



off several branches. The artery then enters 

 the inguinal canal through the internal ring, 

 and emerging at the external, passes down 

 the cord, being surrounded in its course by 

 the spermatic veins. The further distribution 

 of the artery is thus correctly described by 

 Sir A. Cooper : " When the artery reaches 

 from one to three inches from the epididymis, 

 varying in different subjects, it divides into 

 two branches, which descend to the testicle 

 on its inner side, opposite to that on which 

 the epididymis is placed ; one passing on the 

 anterior and upper, the other to the posterior 

 and lower part of the testis. From the anterior 

 branch the vessels of the epididymis arise: 

 first, one which passes to its caput; secondly, 

 another to its body, and, thirdly, one to its 

 cauda and the first convolutions of the vas 

 deferens, communicating freely with the de- 

 ferential artery. The spermatic artery, after 

 giving off branches to the epididymis, enters 

 the testis, by penetrating the outer layer of 

 the tunica albuginea ; and dividing upon its 

 vascular layer, they form an arch by their 

 junction at the lower part of the testis, from 

 which numerous vessels pass upwards ; and 

 then descending, they supply the lobes of the 

 tubuli serniniferi. Besides this lower arch, 

 there is another passing in the direction of 

 the rete, extremely convoluted in its course, 

 and forming an anastomosis between the prin- 

 cipal branches.'' The testis receives a further 

 supply of blood from another vessel, the ar- 

 tery of the vas deferens, or posterior spermatic 

 artery, which arises from one of the vesical 

 arteries, branches of the internal iliac. This 

 artery divides into two sets of branches, one 

 set descending to the vesicula seminalis and 

 to the termination of the vas deferens ; the 

 other, ascending upon the vas deferens, runs 

 in a serpentine direction upon the coat of that 

 vessel, passing through the whole length of 

 the spermatic cord ; and when it reaches the 

 cauda epididymis, it divides into two sets of 

 branches, one advancing to unite with the 

 spermatic artery to supply the testis and epi- 

 didymis, the other passing backwards to the 

 tunica vaginalis and cremaster. 



The spermatic veins spring in three sets 

 from the testicle, one from the rete and tubuli, 

 and another from the vascular layer of the 

 tunica albuginea, and a third from the lower 

 extremity of the vas deferens. The veins of 

 the testicle pass in three courses into the 

 beginning of the spermatic cord ; two of these 

 quit the back of the testicle, one at its anterior 

 and upper part, and a second at its centre ; 

 and these, after passing from two or three 

 inches, become united into one. The other 

 column accompanies the vas deferens. There 

 is also a large vein, just above the testicle, 

 which crosses to join the three columns. The 

 veins of the epididymis are one from the 

 caput, another from its body ; one from its 

 cauda, and another from its junction with the 

 vas deferens, besides some small branches ; 

 they terminate in the veins of the spermatic 

 cord. The veins, after quitting the testicle, 

 become extremely tortuous, and frequently 



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