THE PERINEUM ix THE MALE. 



1203 



been described (page 460). It is a layer of considerable strength, and encloses and 

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

 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 Trans versus perinaei muscles to join the 

 lower margin of the deep perineal fascia. 



It is between this layer of fascia and the next layer, the superficial layer of the deep perineal 

 fascia, that extravasation of urine most frequently takes place in cases of rupture of the urethra. 

 The superficial layer of the deep perineal fascia (see page 463) is also attached to the ischio^pubic 

 rarni, 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 Transversus perinaei muscles ; it cannot extend laterally, 

 on account of the connection of both these layers to the rami of the os pubis and ischium ; it 

 cannot find its way into the pelvis, because the opening into this cavity is closed by the deep 

 perineal fascia : 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 from thence 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 deep perineal fascia in which are contained the peri- 



FIG. 767. Dissection of perinseum and ischio- rectal region. 



neal branches of the internal pudic artery, with their accompanying veins; the 

 perineal branches of the internal pudic nerve; some of the muscles connected 

 with the penis and urethra ; in the middle line, the Accelerator urinae ; on each 

 side, the Erector penis ; and behind, the Transversus perinaei ; the crura 

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

 seen the eentriil f-///<7/,/,/x point of the perinceum. This is a fibrous point in the 

 middle line of the perinaeum between the urethra and the rectum, being about half 

 an inch in front of the anus. At this point five muscles converge and are 

 attached viz. the External sphincter ani, the Acceleratores 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 urinae. the Erector penis, and the Transversus perinaei muscles 

 have been already described (page 461). 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 (deep perineal fascia), and running from behind forward 

 in it are the superficial perineal vessels and nerves, and the transverse perineal 

 artery coursing along the posterior boundary of the space on the Transversus 

 perinaei muscle. The two terminal branches of the internal pudic artery are 

 not to be seen in this space, as they as well as the dorsal nerve of the penis are 

 dorsal to the superficial layer of the triangular ligament : the dorsal artery of the 

 penis ascending between the two layers of the ligament ; and the artery to the cor- 

 pus cavernosum entering the crus immediately after piercing from above downward 



