70 



TOPOGRAPHICAL ANATOMY OF THE 



The skin of the scrotum is thin, soft to the touch, generally darkly 



pigmented, and shiny from the secretion of its numerous sweat and 



sebaceous glands. Hairs are fine and soft and comparatively few in 



number. 



Dissection. — Make an incision through the skin along the raphe, 

 and expose the underlying dartos tunic. When making the incision, 

 remember- that the skin is thin. 



The wall of the scrotum can be resolved into three or four layers, of 

 which the most superficial is formed by the skin. The second layer. 



A. pudenda externa. 



M. cremaster externus. 

 A. abdominalis subcutanea. 



A. dorsalis penis. 



M. retractor 

 penis. 



M. bulbocavernosus 



Right testis 



covered by 



tunica vaginalis. 



Corona 

 glandis. 



Urethral process. 



Fig. 29.— The male external genital organs. 



known as the tunica dartos,^ is pinkish-yellow in colour and contains a 

 considerable quantity of elastic and muscular tissue. Unlike the skin, 

 which forms a single investment for both testes, the dartos tunic is 

 double, that is, each testis is surrounded by its own dartos. The two 

 tunics, meeting in the middle line of the body, form a median septum 

 between the two scrotal cavities — the septum scroti — that splits close 

 to the abdominal wall in order to accommodate the penis. 



Removal of the dartos tunic exposes an ill-defined scrotal fascia, 

 within which is the fourth scrotal layer, the tunica vaginalis, con- 

 sisting of a fibrous lamina lined with a serous membrane. The fibrous 

 layer of the vaginal tunic is continuous with the fascia covering the deep 

 face of the transverse muscle of the abdominal wall, and is in the form 

 of a blunt-pointed, pear-shaped sac, the narrow end of which is con- 

 1 daprds (dartos) [Gr.], flayed, skinny. 



