[68 



ABDOMEN 



Corpus caver- 

 nosum urethrae 



Radix Penis. The root of the penis consists of a middle 

 part, the bulb of the urethra, and right and left lateral parts, 

 the crura of the penis. 



The crura penis are the posterior segments of the corpus 

 cavernosum penis, which forms the dorsal part of the body 

 of the penis. Each is attached to the rami of the pubis and 

 ischium of the corresponding side, and to the adjacent part 

 of the inferior surface of the inferior fascia of the urogenital 

 diaphragm. Its superficial surface is covered by and gives 

 attachment to the corresponding ischio-cavernosus muscle. 



The profunda artery of the 

 penis enters the anterior 

 part of its deep surface, 

 and the corresponding vein 

 issues from it at the same 

 point to form one of the 

 venae comites of the in- 

 ternal pudendal artery. 



The bulb of the urethra 

 is the posterior expanded 

 part of the corpus caver- 

 ncsum urethrae, which lies 

 on the lower surface of 

 the body of the penis, 

 partly embedded in a groove on the inferior aspect of the 

 corpus cavernosum penis. At the anterior end of the penis 

 the corpus cavernosum urethrse enlarges into a cap-like ex- 

 pansion, the glans penis, which covers the anterior end of 

 the corpus cavernosum penis, and posteriorly, in the super- 

 ficial pouch of the urethral triangle it separates from the 

 corpus cavernosum penis and again enlarges to form the bulb 

 of the urethra which is the middle segment of the root of 

 the penis (Figs. 80, 81, 82). 



The bulb of the urethra is attached to the inferior surface 

 of the inferior fascia of the urogenital diaphragm by fibrous 

 tissue and by the bulbo-cavernosus muscles. Immediately 

 anterior to its posterior end, the urethra, the ducts of the 

 bulbo-urethral glands, and the arteries to the bulb, one from 

 each internal pudendal artery, enter it, after they have pierced 

 the inferior fascia of the urogenital diaphragm. Occasionally 

 the posterior end of the bulb is divided by a median notch 

 which indicates its bilateral origin. 



urethrE 



FIG. 79. Transverse section through 

 the body of the Penis. 



