THE SCROTUM 



487 



Its head consists of lobules fLobuli epiclith'inidis), each of which consists of a 

 coiled tubule or conus vasculosus, which succeeds a vas efferens. By the union 

 of these tubules is formed a single tube, the duct of the epididymis (Ductus epididy- 

 midis), which, by its complex coils, forms the l)ody and tail of the epididymis and 

 terminates in the vas deferens. The tubules and the coils of the duct of the 

 epididymis are held together b}" connective tissue and unstriped muscle-fibers. 

 The tubules and duct are lined with ciliated epithelium, and the duct has a mus- 

 cular coat which consists of longitudinal and circular fibers. 



Vessels and Nerves. — The testicle is richly supplied with blood Ijy the sper- 

 matic artery, a branch of the posterior aorta. The artery descends in the anterior 

 part of the spermatic cord, and is very tortuous near the testicle; on reaching the 

 attached border of the gland it passes backward in a flexuous manner, giving 

 branches to the testicle and epididymis, turns around the posterior extremity, 



y 



( 



Fig. 391. — Rir.HT Testicle and Spermatic Cord of 

 Horse, Inclosed in Tunica Vaginalis. 

 c, Tunica vaginalis communis; g, prominence 

 caused by tail of epididymis; p, cremaster externus mus- 

 cle. (After Ellenberger-Baum, Top. Anat. d Pferdes.) 



Fig. 392. — Right Testicle and Spermatic Cord of 

 Horse, Exposed. 

 a' , External surface of testicle; c. tunica vagin- 

 alis, cut and reflected; d, ligament of epididymis; e, 

 mesorchium; <;, tail, h, body, t, bead of epididymis; k, 

 digital fossa or sinus epididymidis; /, spermatic vessels 

 showing through tunica vaginalis propria; m, end of 

 spermatic artery. Dotted line indicates position of vas 

 deferens on other side of mesorchium. (.\fter Ellen- 

 berger-Baum, Top. Anat. d. Pfenles.) 



and runs forward on the free l)order to the anterior extremity. It is partially 

 embedded in the tunica albuginea, and detaches lateral branches which ascend in 

 a tortuous fashion on each surface of the testicle; these give off small branches 

 which enter the gland on the septa. 



The spermatic veins on leaving the testicle, form the pampiniform plexus 

 around the artery in the spermatic cord. The vein which issues from this plexus 

 usually joins the posterior vena cava on the right side, the left renal vein on the 

 left side. 



The nerves, derived from the renal and posterior mesenteric plexuses, form 

 the spermatic plexus around the vessels. 



THE SCROTUM 

 The scrotum, in which the testicles and the lower parts of the spermatic cords 

 are situated, is somewhat glol^ular in form, but is commonly asymmetrical, since 



