MALE PERINEUM 173 



corresponding artery to the bulb. Half an inch farther forwards 

 the dorsal nerve of the penis and the internal pudendal artery 

 or its two terminal branches pierce the fascia on each side, 

 close to the margin of the pubic arch, and under cover of 

 the corresponding crus penis. 



The term " inferior fascia " of the urogenital diaphragm 

 which is applied to this membrane, implies that there is a 

 deeper fascia to be studied in connection with it. But whilst 

 the two fasciae are very intimately connected, they must be 

 looked upon as being distinct structures. The inferior fascia 

 of the urogenital diaphragm is in the same morphological 

 plane as the bony wall of the pelvis and the obturator mem- 

 brane, and, in fact, completes the pelvic wall in front. The 

 superior fascia of the urogenital diaphragm is merely the parietal 

 layer of the pelvic fascia carried round to the front of the 

 pelvis. Consequently the connections of the latter layer can 

 be examined very much better in conjunction with the pelvic 

 fascia. It should now be noted (i) that the two fasciae 

 enclose the urogenital diaphragm ; (2) that the anterior and 

 posterior margins of the two layers are blended together; 

 (3) that the interval between the two is closed laterally by 

 the attachment of both layers to the margins of the pubic 

 arch ; and (4) that the space between the two layers 

 contains : 



1. The membranous portion of the urethra and its sphincter muscle. 



2. The deep transverse perineal muscle. 



3. The bulbo-urethral (Cowper's) glands. 



4. The internal pudendal vessels, the dorsal nerves of the penis, and the 



arteries to the bulb. 



Dissection. To expose these parts, on one side, reflect the 

 inferior fascia of the urogenital diaphragm on that side, but 

 carefully preserve the fascia on the opposite side, so that it may 

 serve as a landmark in the subsequent dissection of the pelvis. 

 On the side selected detach the fascia from the pubic arch, and, 

 cautiously raising it from the subjacent structures, throw it 

 medially towards the bulb. 



As soon as the inferior fascia of the diaphragm is raised the 

 muscles of the diaphragm come into view. They are small and 

 difficult to dissect, therefore great care must be exercised as an 

 attempt is made to clean them and to define their limits. Com- 

 mence with the deep transverse muscle, which lies parallel with 

 the base of the inferior fascia. Its posterior border is not difficult 

 to define. Its anterior border blends with the sphincter muscle 

 of the membranous urethra, which occupies the anterior part 

 of the deep pouch. Clean the superficial surfaces of both 

 muscles. 



