DESCENT OP THE TESTIS. 



627 



downwards along the spermatic cord nearly to the testis. That portion 

 of the peritoneum which immediately surrounds the testis is, by the 

 above process, cut off from its continuity with the peritoneum, and is 

 termed the tunica vaginalis ; and as this membrane must be obviously 



Fig, 185.* 



Fig. i86f. 



a shut sac, one portion of it investing the testis, and the other being 

 reflected so as to form a loose bag around it, its two portions have re- 

 ceived the appellations of tunica vaginalis propria, and tunica vaginalis 

 reflexa. 



The descent of the testis is effected by means of the traction of the 

 muscle of the gubernaculum (cremaster). " The fibres," writes Mr. 

 Curling,^ " proceeding from Poupart's ligament and the obliquus in- 

 ternus, tend to guide the gland into the inguinal canal ; those attached 

 to the os pubis, to draw it below the abdominal ring ; and the process 

 descending to the scrotum, to direct it to its final destination." 

 During the descent " the muscle of the testis is gradually everted, 

 until, when the transition is completed, it forms a muscular envelope 

 external to the process of peritoneum, which surrounds the gland and 

 the front of the cord." " The mass composing the central part of the 



* A diagram illustrating the descent of the testis. 1. The testis. 2. The 

 epididymis. 3- 3. The peritoneum. 4. The pouch formed around the testis 

 by the peritoneum, the future cavity of the tunica vaginalis. 5. The pubic 

 portion of the cremaster attached to the lower part of the testis. 6. The por- 

 tion of the cremaster attached to Poupart's ligament. The mode of eversion of 

 the cremaster is shewn by these lines. 7- The gubernaculum, attached to the 

 bottom of the scrotum, and becoming shortened by the contraction of the mus- 

 cular fibres which surround it. 8, 8. The cavity of the scrotum. 



t In this figure the testis has completed its descent. The gubernaculum is 

 shortened to its utmost, and the cremaster completely everted. The pouch of 

 peritoneum above the testis is compressed so as to form a tubular canal. 1. 

 A dotted line marks the point at which the tunica vaginalis will terminate su- 

 periorly ; and the figure 2 its cavity. 3. The peritoneal cavity. 



i Loc. cit. 



