288 Anatomy Applied to Medicine and Surgery. 



by side, throughout the rest of their extent, except, in 

 front, where they again diverge to accommodate the cor- 

 pus spongiosum which forms the glans penis. The mus- 

 cles connected with the penis are: The erector penis, the 

 accelerator urinae, and the superficial transversus perinei. 

 The erector penis aids in the erection of the penis by com- 

 pressing the venous circulation ; the accelerator urinae 

 assists in ejaculation of the semen, while the transversus 

 perinei acts as an accessory to the accelerator by fixing the 

 raphe from which the fibres of the latter arise. The nerves 

 of the penis are derived from the sympathetic and from 

 the internal pudic. 



The Urethra, about six and a half inches in length, 

 is divided into a prostatic portion, a membranous portion 

 which lies between the two layers of the deep or triangu- 

 lar ligament, and a spongy portion. The shape of the 

 urethra in the different parts of its course is, in the re- 

 laxed condition, as follows : At the meatus urinarius, a 

 vertical slit, a little farther back, T-shaped because of the 

 presence of the lacuna magna in the dorsal wall still 

 farther back, i.e., in the spongy portion, it forms a trans- 

 verse slit, while in the membranous it is stellate, and in 

 the prostate, resembles an inverted U. 



The Scrotum. The integument of the scrotum is 

 thin and presents a median raphe showing the line of 

 union of its two halves. Beneath the skin are the follow- 

 ing layers : ( 1 ) The dartos, containing yellow elastic tis- 

 sue and unstriped muscular fibres. This layer is contin- 

 uous with the superficial fascia of the abdomen and of the 

 perineum. (2) The external spermatic fascia which is 

 continuous with the intercolumnar fascia. (3) The cre- 

 masteric fascia. (4) The internal spermatic fascia the 

 projection downwards of the infundibuliform process of 

 the transversalis fascia. (5) The tunica vaginalis, the un- 



