Male Perineum 439 



diameter averages 3^ in., its transverse 3| in. (vide Planes of Pelvis, 

 p. 364). If a line be drawn between the ischial tuberosities the space 

 is divided into the urethral and the anal triangles ; superficial to the 

 former are the tissues of the perineum ; the posterior is occupied by 

 the lower end of the rectum and the ischio-rectal fossae. Thus the 

 anterior triangle is subservient to genito-urinary functions, and the 

 posterior to the alimentary canal. For the most part these two func- 

 tions have separate and distinct sets of muscles, nerves, and vessels. 



Surface markings. In the middle line is a soft, antero-posterior 

 elevation, caused by the hinder part of the corpus spongiosum and 

 the bulb of the urethra ; over it is the median raphe. The rapJic is 

 not a trustworthy indication to the middle line, it is easily displaced 

 to one side or the other by inflammatory adhesions ; it is the embryonic 

 seam in which the integumental halves of the perineum were joined. 

 At the side of the urethral projection the finger can be thrust into a 

 shallow space beneath which the triangular ligament blocks the front 

 of the pelvic outlet ; more externally can be traced the rami of the 

 pubes and ischium. Passing forwards, the corpus spongiosum loses 

 itself within the base of the scrotum. 



Beneath the skin is the superficial layer of the superficial fascia, 

 which is continuous with the non-striated muscular tissue of the 

 scrotum, laterally with the fat of the buttock, and behind with the fat 

 in the ischio-rectal fossa. This layer of fascia consists of loose con- 

 nective tissue with a little fat ; it has no deep connections. 



The deep layer of the superficial fascia is thin and membranous ; it 

 loosely covers in the corpus spongiosum, and, passing forwards, enters 

 the tissue of the scrotum, becoming continuous with the clartos ; it 

 also invests the penis and passes up on to the abdomen, being attached 

 below to Poupart's ligament and to the iliac crest. Laterally, in the 

 perineum, this important fascia is attached to the pubic and ischial 

 rami ; posteriorly it loses itself on the base of the triangular ligament. 

 An incomplete and unimportant septum attaches the deep surface of 

 this fascia to the triangular ligament. (The student should demon- 

 strate the arrangement of this fascia, with a sheet of muslin, upon a 

 pelvis to which the ligaments are attached.) 



When, in rupture of the urethra, urine is extravasated beneath this 

 fascia, it cannot pass backwards into the fossae, nor laterally on to the 

 buttocks, but, coursing along by the penis and scrotum, it ascends by 

 the spermatic cords to the iliac and hypogastric regions. In the dis- 

 secting-room air forced beneath the fascia takes the same course. 



Perineal abscess. Urine or pus locked in beneath this fascia 

 causes a tense bulging behind the scrotum and beneath its root ; as 

 the fascia is too dense to allow of fluctuation, the tumour may feel as 

 hard and solid as a cartilaginous growth. The pressure of the fluid 

 beneath the urethra drives the floor against the roof, rendering mic- 

 turition difficult, and the introduction of a catheter distressing and 



