chnp. xvin.] THE PERINEUM. 387 



shows very readily any extravasations of blood that 

 may form beneath it. The superficial fascia is divided 

 into two layers, of which the more superficial is quite 

 unimportant, and contains what little subcutaneous 

 fat exists in this part. 



The deeper layer, known as the perineal fascia or 

 fascia of Colles, is attached on either side to the rami 

 of the pubes and ischium, and behind to the base of 

 the triangular ligament. In front it becomes continuous 

 with the dartos tissue. This fascia, therefore, by its 

 attachments forms with the triangular ligament a well- 

 isolated aponeurotic space, containing the bulb with 

 all that part of the spongy urethra between the 

 triangular ligament and the attachment of the scrotum, 

 the penile muscles, the transverse perineal muscles, 

 vessels, and nerves, and the pevineal vessels and nerves. 

 When extravasation of urine follows upon a rupture 

 of the part of the urethra above named, the course of 

 the escaping fluid is directed by the fascia of Colles. 

 It fills the aponeurotic space. It is unable to gain to 

 ischio-rectal fossa on account of the attachment of the 

 fascia to the triangular ligament. The lateral attach- 

 ments of this membrane prevent the urine from 

 passing into the thighs. It is, therefore, guided into 

 the scrotum, and there finds itself beneath the 

 dartos tissue. It distends the scrotal tissues, and 

 then mounts up on to the abdomen through the gap 

 left between the symphysis pubis and pubic spine 

 (page 291). It must be remembered that the fascia 

 of Colles, the dartos tissue, and the deeper layer of 

 the superficial fascia of the abdomen, are continuous, 

 and merely represent different parts of the same 

 structure. Pus or blood within this aponeurotic 

 space would follow the same course if the effusion 

 were extensive enough. The pain occasioned by 

 such effusion can be understood when it is noted 

 that the three chief sensory nerves of this region 



