MALE PERINEUM 165 



diaphragm (O.T. superficial layer of the triangular ligament), 

 and superior fascia of the urogenital diaphragm (O.T. deep 

 layer of the triangular ligament) form the transverse ligament of 

 the pelvis, and their blended posterior margins form the base of 

 the urogenital diaphragm. 



The space between the two fasciae of the urogenital dia- 

 phragm is spoken of as the deep pouch of the urethral triangle 

 of the perineum, in contradistinction to the superficial pouch 

 which lies between the inferior fascia of the diaphragm and 

 the fascia of Colles and has already been examined. 



The deep pouch of the urethral triangle contains the deep 

 transverse muscle of the perineum and the sphincter muscle 

 of the membranous urethra, which constitute the muscular 

 portion of the urogenital diaphragm ; the membranous part 

 of the urethra; the bulbo- urethral glands; the internal 

 pudendal arteries ; their branches to the bulb of the urethra 

 and their terminal branches the dorsal arteries of the penis 

 and the profunda arteries of the penis ; the terminal branches 

 of the deep division of the perineal nerve and the dorsal 

 nerve of the penis. 



The membranous part of the urethra enters the deep 

 pouch by piercing the superior fascia of the urogenital dia- 

 phragm and leaves it by piercing the inferior fascia. It is 

 accompanied at its exit by the ducts of the bulbo-urethral 

 glands. Each internal pudendal artery and each dorsal 

 nerve of the penis enters the posterior part of the deep 

 pouch at the anterior end of the canal in the obturator 

 fascia. The terminal branches which the internal pudendal 

 artery gives off in the deep pouch leave the pouch by piercing 

 the inferior fascia of the urogenital diaphragm. The dorsal 

 nerve of the penis accompanies the dorsal artery of the penis, 

 which is one of the terminal branches of the internal 

 pudendal artery. 



Dissection. Follow the constituent parts of the root of the 

 penis forwards until they blend to form the body of the penis. 

 Note (i) that the bulb of the urethra diminishes in size as it 

 passes forwards to the under surface of the body of the penis 

 where it forms the middle part of the corpus cavernosum 

 urethras, the bulb of the urethra being the posterior part and 

 the glans penis the anterior part of that structure. (2) That 

 immediately below the apex of the pubic arch the crura of the 

 penis blend together on the dorsum of the penis to form the corpus 

 cavernosum penis, which constitutes the large dorsal part of the 

 body of the penis. 



After the constituent parts of the root of the penis have been 

 n116 



