OF THE PERINEUM. 



373 



by the Transversus perinaei. The floor of this space is formed by the triangular 

 ligament of the urethra (deep perineal fascia), and running from behind forward 

 in it are the superficial perineal vessels and nerves, the long pudendal nerve ; the 

 transverse perineal artery coursing along the posterior boundary of the space on 

 the Transversus perineei muscle. 



The Triangular Ligament (Deep perineal fascia] is stretched almost horizontally 

 across the pubic arch, so as to close in the front part of the outlet of the pelvis. 

 It consists of two dense membranous laminae, which are united along their 

 posterior borders, but are separated in front by intervening structures. The 

 superficial of these two layers, the inferior layer of the triangular ligament, is 

 triangular in shape, about an inch and a half in depth. Its apex is directed 

 forward, and is separated from the subpubic ligament by an oval opening for the 

 transmission of the dorsal vein of the penis. Its lateral margins are attached on 

 each side to the rami of the ischium and os pubis, above the crura penis. Its base 

 is directed toward the rectum, and connected to the central tendinous point of the 

 perinaeum. It is continuous with the deep layer of the superficial fascia behind 

 the Transversus perinaei muscle, and with a thin fascia which covers the cutaneous 

 surface of the Levator ani muscle (anal or ischio-rectal fascia). 



Anterior layer of 

 deep perineal fascia removed, 



showing 



COMPRESSOR URETHRA:. 

 Internal pudic artery. 

 -Artery of the bulb. 

 Cowper's gland. 



FIG. 226. Triangular ligament or deep perineal fascia, 

 removed. 



On the left side the superficial layer has been 



This layer of the triangular ligament is perforated, about an inch below the 

 symphysis pubis, by the urethra, the aperture for which is circular in form and 

 about three or four lines in diameter ; by the arteries to the bulb and the ducts of 

 Cowper's glands close to the urethral orifice ; by the arteries to the corpora caver- 

 nosa one on each side, close to the pubic arch and about halfway along the 

 attached margin of the ligament ; by the dorsal arteries and nerves of the penis 

 near the apex of the ligament. Its base is also perforated by the superficial 

 perineal vessels and nerves, while between its apex and the subpubic ligament the 

 dorsal vein of the penis passes upward into the pelvis. 



If this superficial or inferior layer of the triangular ligament is detached on 

 either side, the following structures will be seen between it and the deeper layer: 

 the dorsal vein of the penis ; the membranous portion of the urethra, and the 



