130 



HUMAN EMBRYOLOGY AND MORPHOLOGY. 



the downgrowth of the gubernacular bud which pushes its way to 

 the scrotum (Figs. 103 and 104). The gubernaculum grows 

 downwards as a solid fibro-muscular mass, until it reaches the 

 subcutaneous tissue which at that time completely fills the 

 scrotum. Its attachment to the scrotum is slight and easily 

 broken. The gubernaculum, as it grows through the abdominal 

 wall, carries with it : — 



(1) A process of peritoneum (the processus vaginalis) ; 



(2) The trans versalis fascia (the infundibuliform fascia) ; 



(3) The internal oblique and transversalis muscles to form the 

 cremaster ; 



(4) The spermatic fascia from the external oblique ; 



(5) The deep layer (Scarpa's) of the superficial fascia of the 

 groin. All these layers are added to the primitive coverings of 

 the scrotum, which until then is made up simply of skin and 

 superficial fascia (Fig. 104). 



peritoneum 



plica vascularis. 



testis 



Pouparts lig. 

 gubernaculum 



internal ob. 

 peritoneum 



cremaster 

 penis 

 processus, uag. 



scrotum 



Fig. 104.— The manner in which the structures in the wall of the abdomen are carried 

 out so as to form the Inguinal Canal and Coverings of the Testis. 



It will be thus seen that the gubernaculum testis is an actively 

 growing mass of fibro-muscular tissue, which starting from the 

 inner muscular layer of the abdominal parietes in the groin, in- 

 vades first the plica gubernatrix and then the abdominal wall 

 itself, every layer of which it carries as a prolongation within the 

 scrotum. .It is an invading army of cells. It draws with it into 

 the scrotum the peritoneum in the iliac fossa, on which the testis 

 is dragged like a log on a sledge. 



