438 CLINICAL APPLIED ANATOMY. 



found here, and that the urethra is usually torn by injury in this 

 region. Stricture may also occur in the penile part, but it never 

 occurs in the prostatic portion. 



Extravasation of Urine. Extravasation of urine is most 

 usually caused by a giving way of the wall of the urethra. This 

 may be induced by, (1) a peri-urethral abscess, generally the 

 result of gonorrhoea, and usually on the proximal side of a 

 stricture, opening into the urethra, thus allowing urine to be 

 forced into the emptied cavity of the abscess during micturition, 

 and if the pressure is great the extravasation may be wide- 

 spread : (2) laceration of the urethra as the outcome of falls 

 astride, or blows upon the perineum. Here blood will pass from 

 the meatus independently of micturition, and should the patient 

 attempt to pass urine, some of it will invariably be extravasated 

 through the rupture ; (3) perforation of the wall of the urethra 

 by the forcible use of instruments ; (4) the giving way of the 

 dilated and perhaps even ulcerated wall of that portion of the 

 urethra immediately proximal to the site of a stricture ; (5) lacera- 

 tions of the urethra associated with fracture of the bones of the 

 pelvis. 



If it is the membranous part of the urethra which has given 

 way, urine will pass into the substance of the compressor urethras 

 muscle between the two layers of the triangular ligament, and 

 theoretically, should be limited to this space, but usually trans- 

 gresses it in a superficial direction. Extravasation, however, is 

 far more common in front of, that is superficial to, the anterior 

 layer of the triangular ligament. Here there is a space which is 

 securely limited behind and at the sides, but open in front. It 

 is sometimes spoken of as the superficial compartment of the 

 urogenital triangle, and has the following boundaries, which 

 readily serve to limit the progress of extravasated urine, and 

 direct its advance in one direction only. Superficially are found 

 the skin and two layers of superficial fascia. The superficial 

 layer of this fascia is continuous with the subcutaneous tissue of 

 the thighs, scrotum, penis and the lower part of the anterior 

 abdominal wall. The deep layer of this fascia is distinctly 



