DEEP PERINEAL FASCIA. 181 



the Levator ani into the side of the vagina. The other muscles are precisely 

 similar to those in the male. 



The Deep Perineal Fascia (triangular ligament) is a dense membranous lamina, 

 which closes the front part of the outlet of the pelvis. It is triangular in shape, 

 about an inch and a half in depth, attached above, by its apex, to the under 

 surface of the symphysis pubis and sub-pubic ligament ; and, on each side, to the 

 rami of the ischia and pubes, beneath the crura penis. Its inferior margin or 

 base is directed towards the rectum, and connected to the central tendinous point 

 of the perineum. It is continuous with the deep layer of the superficial fascia, 

 in front of the Transversus perinei muscle, and with a thin fascia, which covers 

 the outer surface of the Levator ani muscle. 



The deep perineal fascia is perforated by the urethra, about an inch below the 

 symphysis pubis. The aperture is circular in form, and about three or four lines 

 in diameter. Above this is the aperture for the dorsal vein of the penis ; and 

 outside the latter, the pudic nerve and artery pierce it. 



The deep perineal fascia consists of two layers, anterior and posterior : these 

 are separated above, but united below. 



The anterior layer is continued forwards, around the anterior part of the mem- 

 branous portion of the urethra, becoming lost upon the bulb. 



The posterior layer is derived from the pelvic fascia : it is continued backwards 

 around the posterior part of the membranous portion of the urethra, and the 

 outer surface of the prostate gland. 



If the anterior layer of this fascia is detached on either side, the following 

 parts are seen between it and the posterior layer : the sub-pubic ligament above, 

 close to the pubes ; the dorsal vein of the penis ; the membranous portion of the 

 urethra, and the muscles of the urethra ; Cowper's glands, and their ducts ; the 

 pudic vessels and nerve; the artery and nerve of the bulb, and a plexus of 

 veins. 



The Compressor Urethrse (constrictor urethroe) surrounds the whole length of 

 the membranous portion of the urethra, and is contained between the two layers 

 of the deep perineal fascia. It arises by aponeurotic fibres, from the upper part 

 of the ramus of the pubes on each side, to the extent of half or three quarters of 

 an inch ; each segment of the muscle passes inwards, and divides into two 

 fasciculi, which surround the urethra from the prostate gland behind, to the 

 bulbous portion of the urethra in front ; and unite, at the upper and lower sur-^ 

 faces of this tube, with the muscle of the opposite side, by means of a tendinous 

 raphe. 



Circular muscular fibres surround the membranous portion of the urethra, from 

 the bulb in front to the prostate gland behind : they are placed immediately beneath 

 the transverse fibres already described, and are continuous with the circular fibres 

 of the bladder. These fibres are involuntary. 



Cowper's Glands are situated immediately below the membranous portion of the 

 urethra, close behind the bulb, and below the artery of the bulb (p. 736). 



The Pudic vessels and Nerves are placed along the inner margin of the pubic arch 

 (p. 433). 



The Artery of the Bulb passes transversely inwards from the internal pudic along 

 the base of the triangular ligament, between the two layers of fascia, accompanied 

 by a branch of the pudic nerve (p. 434). 



If the posterior layer of the deep perineal fascia is removed, and the crus 

 penis of one side detached from the bone, the under or perineal surface of the 

 Levator ani is brought fully into view. This muscle, with the triangular ligament 

 in front and the Coccygeus and Pyriformis behind, closes in the outlet of the 

 pelvis. 



The Levator ani is a broad thin muscle, situated on each side of the pelvis. It 

 is attached to the inner surface of the sides of the true pelvis, and, descending, 

 unites with its fellow of the opposite side to form the floor of the pelvic cavity. 

 It supports the viscera in this cavity, and surrounds the various structures which 



