THE TESTIS. 



1287 



attached to the posterior border of the testis. Each border ends above in the 

 superior extremity, and below in the inferior extremity of the testis. Owing to an 

 obliquity of the long axis of the gland, the superior extremity of the testis lies on 

 a more anterior and lateral plane than the inferior extremity. 



Epididymis. The epididymis is a somewhat crescentic structure, which is curved 

 round the posterior border of the testis and overlaps to some extent the posterior 

 part of the lateral surface of that organ. The superior, somewhat swollen part of 

 the epididymis, is called the caput epididymidis or head, and overhangs the superior 

 end of the testis, to which it is directly connected by numerous emerging ducts, by 

 connective tissue, and by the serous covering of the organ. The inferior and smaller 

 end is termed the cauda epididymidis or tail, and is attached by loose areolar tissue 

 and by the serous covering to the inferior end of the testis. The intermediate part, 

 the body, or corpus epididymidis, is applied against, but is separated from, the 

 posterior part of the lateral surface of the testis by an involution of the serous 

 covering of the organ, which forms an intervening pocket termed the sinus epi- 

 didymidis (O.T. digital fossa). 



The main mass of the epididymis is composed of an irregularly twisted canal, 

 the ductus epididymidis, which forms the first part of the duct of the testis. 



Minute sessile, or pedunculated, bodies are often found attached to the head of the 

 epididymis or to the superior end of the testis. These are called appendices of the 

 epididymis and testis (O.T. hydatids of Morgagni), and have a developmental interest. 

 The minute body which lies on the superior end of the testis represents the free end of 

 Miiller's duct in the embryo and the fimbriated 'fend of the uterine tube of the female ; it 

 is usually sessile. Above the head of the epididymis, and in front of the lower part of 

 the spermatic cord, there may also be present a small rudimentary body called the 

 paradidymis. This is rarely seen in the adult, and is best marked in young children. 



Tunica Vaginalis. The cavity within which the testis and epididymis are 

 placed is lined by a smooth serous membrane the tunica vaginalis which 

 resembles in appearance and structure 

 the peritoneum, from which it is origin- 

 ally derived. The cavity is considerably 

 larger than the contained structures, 

 and extends not only down to a lower 

 level than the testis, but also reaches 

 upwards to a higher level than the 

 gland. The sac, or cavity, tapers as 

 it is traced upwards, and above the 

 level of the testis the funiculus sper- 

 maticus or spermatic cord bulges 

 forwards into its posterior part. The 

 tunica vaginalis lines the cavity for 

 the testis, and is reflected from the 

 posterior wall of the scrotal chamber 

 over the testis and epididymis, giving 

 a covering to each. The part of the 

 membrane lining the cavity is called 

 the lamina parietalis or parietal portion 

 of the tunica vaginalis, while the part 

 clothing the testis and epididymis is 

 termed the lamina visceralis or visceral FlG ' 1004 -- LEFT TESTIS 



DOrtion TWwppn rha latArol enrfpnp A part of the tunica vaginalis has been removed in order to 



show the ductuli efferentes and lobuli epididymidis. 



the testis and the body of the 



epididymis, the visceral part of the tunica vaginalis dips in and lines a narrow 

 interval called the sinus epididymidis (O.T. digital fossa). The entrance to the sinus 

 is limited above and below by short crescentic folds of the tunica vaginalis, which 

 pass from the testis to the head and tail of the epididymis. These folds are spoken 

 of as the superior and inferior ligaments of the epididymis. In three positions the 

 surface of the testis receives no covering from the tunica vaginalis superiorly 



Spermatic cord 



Body of 

 epididymis 



Sinus of 

 epididymis 



