1948 



HUMAN ANATOMY. 



Fig. 1660. 



Fibrous envelope 



Canal of 

 epididymis 



in the canal of the epididymis, the tubules become narrowed and surrounded by a 

 thin layer of circularly disposed involuntary muscle. The canal of the epididymis — 

 from .4-5 mm. in diameter — is lined throughout by a double layer of tall and 

 slender columnar cells, the free ends of which bear groups of cilia of exceptional 

 length that adhere and form pointed tufts surmounting the cells. A noteworthy 

 feature of the wall of the canal is the layer of involuntary muscle, from .015-030 mm. 

 in thickness, that enqircles the membrana propria and, especially in the globus minor, 



almost entirely replaces the stroma 

 of the mucous membrane. Exter- 

 nally the muscle fades into the con- 

 nective tissue holding together the 

 convolutions of the canal. 



Vessels of the Testis and 

 Epididymis. — The arteries sup- 

 plying these organs are the sper- 

 matic and the deferential, the former 

 being distributed especially to the 

 testis and the latter to the epi- 

 didymis. An additional source is 

 provided by anastomoses with the 

 cremasteric artery. The spermatic 

 artery (a. testicularis) — a slender 

 branch from the abdominal aorta 

 arising a short distance below the 

 renal — is distinguished by its long 

 course necessitated by the migra- 

 tion of the sexual gland from the 

 lumbar region into the scrotum. 

 On reaching the posterior surface of 

 the testicle, it divides into three or 

 four branches that enter the medi- 

 astinum and break up into super- 

 ficial and deep twigs, which follow 

 the tunica albuginea and the septa 

 respectiA'ely and form the rich ca- 

 pillary net-works surrounding the 

 seminiferous tubules. One or more 

 branches pass to the head of the 

 epididymis and anastomose with the 

 artery of the vas. The latter fa. deferentialis), from the inferior or superior vesical, 

 accompanies the spermatic duct and supplies chiefly the body and tail of the epididy- 

 mis, by its connections with the spermatic artery establishing an anastomosis that 

 may become of importance in maintaining the nutrition of the testicle. 



The vei7is, superficial and deep, emerge from the testis and, joining with those 

 from the globus major, form several stems of considerable size that ascend within the 

 spermatic cord in front of the vas deferens, while those from the body and tail of 

 the epididymis unite into a smaller posterior group that accompany the canal 

 (page i960). 



The lymphatics of the testicle, beginning in the walls of the tubules and the sur- 

 rounding connective tissue, follow in general the course of the veins as a superficial 

 and a deep set, and emerge as a half-dozen or more relatively large trunks to which 

 the lymphatics of the epididymis are tributary. Within the spermatic cord they ac- 

 company the groups of veins, and finally empty into the lumbar lymph-nodes. 



The nerves of the testis and epididymis, chiefly sympathetic fibres destined 

 for the walls of the blood-vessels, accompany the latter as the spermatic and the 

 deferential plexuses that surround the corresponding arteries. Medullated fibres, 

 probably conveying sensory impressions, occur among the more usual pale ones. 

 The relations between the terminations of the nerves and the tubules are uncertain, 

 Letzerich and Sclavunos describing intercellular filaments within the canals in addition 



Blood- 

 vessels 



Attachment 

 to testis 



Intertubular 

 stroma 



Vas aberrans 



Vas deferens 

 Section across lower part of epididymis. 



X 15- 



