THE ABDOMEN 615 



subdivided into two compartments by an incomplete septum, which 

 extends upwards from the deep or superior surface of the fascia of 

 Colles to be attached to the median raphe above. This septum is 

 only complete for a short distance at the back part ; elsewhere it 

 is very imperfect, and is continued forwards into the scrotum. 



When air is blo\vn beneath the back part of the fascia of Colles on 

 one side of the middle line, the fascia of that side and the correspond- 

 ing half of the scrotum become distended. As more air is blown in, 

 the fascia of the opposite side and the corresponding half of the 

 scrotum also become distended. 



It is into the perineal pouch that urine is extravasated in rupture of the 

 urethra in the perineum. In such cases the urine cannot pass into either 

 ischio-rectal fossa, its backward course being arrested at the posterior borders 

 of the superficial transverse perineal muscles, where the fascia of Colles, as 

 a whole, turns round to join the base of the triangular ligament. Neither 

 can the urine make its way down the inner side of the thigh, its passage in 

 this direction being stopped at the ischio-pubic ramus to which the fascia 

 of CoUes is attached. The only course, therefore, which is impressed upon 

 the extravasated urine is fonvards into the scrotal wall and on to the penis, 

 in each case beneath the dartos tunic, whence it passes upwards along the 

 spermatic cord to the anterior wall of the abdomen, in which situation it lies 

 beneath the fascia of Scarpa. 



The fascia of Colles covers the following structures : the crura 

 penis, covered by the ischio - cavemosi muscles ; the bulb of the 

 urethra, covered by the bulbo-cavernosi muscles ; the superficial 

 transverse perineal muscles ; the superficial perineal vessels of each 

 side ; the three long scrotal nerves of each side ; and the deep 

 perineal triangle of each side, in the area of which is one half of 

 the antero-inferior layer of the triangiilar ligament. 



Muscles — Transversus Perinaei Superflciaiis — Origin. — ^The inner 

 aspect of the tuber ischii above the origin of the ischio-cavernosus. 



Insertion. — ^The central tendinous point of the perinemn. 



Nerve-supply. — ^The deep division of the perineal branch of the 

 pudic nerve. 



Action. — ^To draw back and fix the central tendinous point, and 

 so' to aid the action of the bulbo-cavemosus. 



The muscle is directed obliquely inwards and forwards, being 

 accompanied by the transverse perineal artery, and it forms the 

 base of the deep perineal triangle. 



Ischio-cavernosus (erector penis) — Origin. — (i) The inner aspect 

 of the tuber ischii close below the origin of the superficial transverse 

 perineal muscle ; and (2) the inner border of the ramus of the 

 ischium on either side of the crus penis. 



Insertion. — The under surface of the fibrous sheath of the crus 

 penis in its front part, and the outer and upper surfaces of the 

 fibrous sheath of the corpus cavernosum penis, in which latter 

 situation it is continuous with the fascial investment of the penis 

 and with the insertion of the suspensory ligament of that organ. 



Nerve-supply. — ^The deep division of the perineal branch of the 

 pudic nerve. 



