204 ANATOMY OF THE ABDOMEN, ETC. 



encircle the penis ; the posterior fibres are inserted into the 

 ramus of the pubes and ischium, the middle surround the 

 corpus spongiosum, and the anterior, spreading upon the 

 corpora cavernosa, are inserted into their investing fascia. 



By dividing the muscles inserted into the perineal centre, an< 

 reflecting them, the bulb of the corpus spongiosum penis will b 

 exposed, and, directly behind it, a strong fascia named the triangular 

 ligament, through which the membranous portion of the urethra 



The TRIANGULAR LIGAMENT, so called from its occupying 

 the triangular space formed by the arch of the pubes, is 

 the deep perineal fascia, extending from one ramus of the 

 ischium and os pubis to the other ; it is composed of two 

 layers, the anterior of which unites with the superficial 

 fascia in front of the anus, and the posterior, passing 

 backward, invests the membranous urethra and prostate, 

 and becomes continuous with the pelvic fascia. It furnishes 

 one of the chief supports and means of resistance to the 

 superincumbent weight of viscera pressing down upon the 

 perineum. The anterior layer of the triangular ligament 

 is traversed by the urethra, and the edges of the opening 

 through which it passes are continuous with the fibrous 

 sheath of the corpus spongiosum. Between the two la} T ers 

 lie the compressor muscle of the urethra, Cowper's glands, 

 and, for a part of their course, the external pudic arteries, 

 and arteries of the bulb. 



The artery of the bulb is a branch of considerable size, 

 arising from the internal pudic; it passes transversely in- 

 ward to the bulbous portion of the corpus spongiosum, to 

 which it is distributed. 



COWPER'S GLANDS, one on each side, are small bodies, 

 the size of a pea, situated behind the bulb of the corpus 

 spongiosum, between the two layers of the triangular liga- 

 ment ; they secrete a fluid carried by a duct into the bulb- 

 ous portion of the urethra. Their size, and the nature of 

 the locality in which they exist, often render them difficult 

 to demonstrate. 



The erector penis muscle is to be dissected away on one side, from 

 the ramus of the pubes and ischium, keeping close to the bone ; this 

 will permit the dissection of the internal pudic artery. 



The removal of the erector penis shows the strong ten- 

 dinous nature of that muscle at its origin from the bone ; 



