378 THE ABDOMEN AND PELVIS 



this region in irritative conditions of those viscera which receive 

 their nerve-supply from the same source, e.g. bladder, rectum, 

 seminal vesicles, etc. It has already been pointed out (p. 372) 

 that irritation of the perineal nerves may reflexly affect the 

 viscera mentioned. 



The Urogenital Diaphragm separates the perineum from 

 the pelvis anteriorly. It is formed by the sphincter urethrse 

 and the deep transverse perineal muscles, which are enclosed 

 between two layers of fascia. The two fascial layers blend 

 with one another and with the fascia of Colles inferiorly, and 

 they are attached on each side to the margin of the pubic arch. 

 The superior fascia (deep layer of triangular ligament) consists 

 of parietal pelvic fascia (p. 356), while the inferior fascia 

 (superficial layer of triangular ligament) forms the postero- 

 superior wall of the superficial perineal pouch. The space 

 between the two layers is completely closed and is termed the 

 deep perineal pouch. It contains (i) the membranous portion 

 of the urethra and its sphincter muscle, (2) the deep transverse 

 perineal muscle and the bulbo-urethral glands (of Cowper), 

 (3) the artery to the bulb, and (4) the internal pudendal vessels 

 and the dorsal nerve of the penis. 



Rupture of the membranous portion of the urethra leads to 

 extravasation of urine into the deep perineal pouch, and the 

 extravasated urine can only find an exit from this space by 

 bursting through either the anterior or the posterior wall of the 

 pouch. In the first case, the urine then passes into the superficial 

 perineal pouch, and its subsequent course is described on p. 376. 

 In the second case it enters the interval which lies immediately 

 below the pubo-prostatic ligaments (Fig. 115); and bursts 

 through between them, gaining the space of Retzius. It then 

 ascends the anterior abdominal wall between the trans versalis 

 fascia and the parietal peritoneum. Extravasated urine will 

 also be found in this situation after rupture of the prostatic 

 urethra, and after extra-peritoneal rupture of the bladder. 



The Internal Pudendal Artery, on leaving Alcock's canal, 

 pierces the base of the urogenital diaphragm and runs forwards 

 in the lateral part of the deep perineal pouch. It pierces the 

 inferior fascia of the diaphragm under cover of the cms penis 

 and ends by dividing into the deep artery of the penis (artery to 

 the corpus cavernosum} and the dorsal artery of the penis. Before 

 it enters the pouch, it gives off superficial branches, which ramify 

 in the superficial pouch and supply the muscles and skin. 



