THE PERINEUM PROPER IN THE MALE. 



1065 



been described (page 370). It is a layer of considerable strength, and encloses and 

 covers a space in which are contained muscles, vessels, and nerves. It is continu- 

 ous in front with the dartos of the scrotum ; on each side it is firmly attached to 

 the margin of the ischio-pubic ramus and to the tuberosity of the ischium ; and 

 posteriorly it curves down behind the Transversus peririaei muscles to join the base 

 of the triangular ligament. 



It is between this layer of fascia and the triangular ligament of the urethra that extravasa- 

 tion of urine most frequently takes place in cases of rupture of the urethra. The triangular 

 ligament of the urethra (see page .'J7.'!i is attached to the ischio-pubic mini, and in front to the 

 subpubic ligament. It is clear, therefore, that when extravasation of fluid takes place between 

 these two layers, it cannot pass backward, because the two layers are continuous with each other 

 around the Trans versi perinsei muscles : it cannot extend laterally, on account of the connection 

 of both these layers to the mini of the os pubis and ischium ; it cannot find its way into the 

 pelvis, because the opening into this cavity is closed by the triangular ligament, and, therefore, 

 so long as these two layers remain intact, the only direction in which the fluid can make its way 

 is forward into the areolar tissue of the scrotum and penis, and then on to the anterior wall of 

 the abdomen. 



When the deep layer of the superficial fascia is removed, a space is exposed, 

 between this fascia and the triangular ligament, in which are contained the super- 

 ficial perineal vessels and nerves and some of the muscles connected with the penis 

 and urethra, viz., in the middle line, the Accelerator urinae ; on each side, the 

 Erector penis; and behind, the transversus perinaei ; together with the crura of 

 the corpora cavernosa and the bulb of the corpus spongiosum. Here also is seen 

 the central tendinous point of the perineum. This is a fibrous point in the middle 

 line of the perineum between the urethra and the rectum, being about half an inch 

 in front of the anus. At this point four muscles converge and are attached, viz., 



FIG. 590. Dissection of perinseum and ischio-rectal region. 



the External sphincter ani, the Accelerator urinae, and the two Transversi perinaei 

 muscles ; so that by the contraction of these muscles, which extend in opposite 

 directions, it serves as a fixed point of support. 



The Accelerator urimie, the Erector penis, and the Transversus perinsei muscles 

 have been already described (page 371). They form a triangular space, bounded, 

 internally, by the Accelerator urinae ; externally, by the Erector penis ; and 

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

 triangular ligament of the urethra; and running from behind forward in it are the 

 superficial perineal vessels arid nerves, and the transverse perineal artery coursing 

 along the posterior boundary of the space, on the Transversus perinaei muscle. 



The Accelerator urinte and Erector penis should now be removed, when the triangular liga- 

 ment of the urethra will be exposed, stretching across the front of the outlet of the pelvis. 

 The urethra is seen perforating its centre, just behind the bulb ; and on each side is the crus 

 penis, connecting the corpus cavernosum with the rami of the ischium and os pubis. 



The Triangular Ligament, which has already been described (see page 373), 

 consists of two layers, the inferior superficial layer of which is now exposed. 



