SPLANCHNOLOGY 



The posterior border, to which the cord is attached, receives only a partial invest- 

 ment from that membrane. Lying upon the lateral edge of this posterior border 

 is a long, narrow, flattened body, named the epididymis. 



The epididymis consists of a central portion or body; an upper enlarged extremity, 

 the head (globus major); and a lower pointed extremity, the tail (globus minor), 

 which is continuous with the ductus deferens, the duct of the testis. The head 

 is intimately connected with the upper end of the testis by means of the efferent 

 ductules of the gland; the tail is connected with the lower end by cellular tissue, 

 and a reflection of the tunica vaginalis. The lateral surface, head and tail of the 

 epididymis are free and covered by the serous membrane; the body is also com- 

 pletely invested by it, excepting along its posterior border; while between the 

 body and the testis is a pouch, named the sinus of the epididymis (digital fossa). 

 The epididymis is connected to the back of the testis by a fold of the serous 

 membrane. 



Appendages of the Testis and Epididymis. On the upper extremity of the testis, 

 just beneath the head of the epididymis, is a minute oval, sessile body, the appendix 

 of the testis (hydatid ofMorgagni) ; it is the remnant of the upper end of the Miillerian 

 duct. On the head of the epididymis is a second small stalked appendage (some- 

 times duplicated) ; it is named the appendix of the epididymis (pedunculated hydatid), 

 and is usually regarded as a detached efferent duct. 



The testis is invested by three tunics: the tunica vaginalis, tunica albuginea, 

 and tunica vasculosa. 



The Tunica Vaginalis (tunica vaginalis propria testis) is the serous covering of 

 the testis. It is a pouch of serous membrane, derived from the saccus vaginalis 

 of the peritoneum, which in the fetus preceded the descent of the testis from the 

 abdomen into the scrotum. After its descent, that portion of the pouch which 

 extends from the abdominal inguinal ring to near the upper part of the gland 

 becomes obliterated; the lower portion remains as a shut sac, which invests the 

 surface of the testis, and is reflected on to the internal surface of the scrotum; 

 hence it may be described as consisting of a visceral and a parietal lamina. 



The visceral lamina (lamina visceralis) covers the greater part of the testis and 

 epididymis, connecting the latter to the testis by means of a distinct fold. From 

 the posterior border of the gland it is reflected on to the internal surface of the 

 scrotum. 



The parietal lamina (lamina parietalis) is far more extensive than the visceral, 

 extending upward for some distance in front and on the medial side of the cord, 

 and reaching below the testis. The inner surface of the tunica vaginalis is 

 smooth, and covered by a layer of endothelial cells. The interval between the 

 visceral and parietal laminae constitutes the cavity of the tunica vaginalis. 



The obliterated portion of the saccus vaginalis may generally be seen as a fibro- 

 cellular thread lying in the loose areolar tissue around the spermatic cord; some- 

 times this may be traced as a distinct band from the upper end of the inguinal 

 canal, where it is connected with the peritoneum, down to the tunica vaginalis; 

 sometimes it gradually becomes lost on the spermatic cord. Occasionally no trace 

 of it can be detected. In some cases it happens that the pouch of peritoneum does 

 not become obliterated, but the sac of the peritoneum communicates with the 

 tunica vaginalis. This may give rise to one of the varieties of oblique inguinal 

 hernia (page 1187). In other cases the pouch may contract, but not become 

 entirely obliterated; it then forms a minute canal leading from the peritoneum to 

 the tunica vaginalis. 



The Tunica Albuginea is the fibrous covering of the testis. It is a dense membrane, 

 of a bluish-white color, composed of bundles of white fibrous tissue which interlace 

 in every direction. It is covered by the tunica vaginalis, except at the points of 

 attachment of the epididymis to the testis, and along its posterior border, where 





