260 FASCIA OF THE PERIK/EUM AND PELVIS. 



The deep perinc&al or subpubic fascia is stretched across the pubic arch 

 on the deep surface of the crura of the penis and the bulb of the urethra. 

 It consists of two distinct layers of strong fibrous membrane, separated by 

 intervening structures. The anterior layer, or triangular ligament of the 

 urethra, attached to the inferior margin of the syinphysis pubis and to the 

 rami of the pubic and ischial bones, and extending in the middle line back 

 to the central point of the periuseum, is perforated about an inch from the 

 symphysis by the urethra, immediately before its expansion into the bulb, 

 and above and in front of this by the dorsal vein of the penis in the 

 middle line, and by the pudic arteries and nerves on each side. At its 

 posterior and inferior extremity it is connected with the deep layer, 

 and with the recurved margin of the perineeal fascia. Between the two 

 layers of the subpubic fascia are placed the membranous portion of the 

 urethra, the deep transverse and constrictor muscles of the urethra, and 

 Cowper's glands, together with the pudic arteries and nerves and the arteries 

 of the bulb. The posterior or deep layer consists of a right and left lateral 

 half, which are separated in the middle line by the urethra close to the neck 

 of the prostate, and are continued into the capsule of that gland. This 

 layer of fascia is superficial to the anterior fibres of the levator ani muscle, 

 which lie between it and the pelvic fascia, and is connected, not only with 

 the superficial layer, but likewise with a thin web of areolar tissue which 

 lies on the surface of the levator ani muscle, and is distinguished as the 

 anal fascia. 



In the female the subpubic fascia is divided in the middle by the vagina. 



EASCTJE OF THE PELVIS. 



The fascia lining the pelvis is described in three parts, viz., the upper 

 part, or undivided pelvic fascia, and the two lower the recto-vesical fascia, 

 and the obturator fascia. The first of these is divided into the other two 

 at the level of a white band of fibres, stretched from the lower part of the 

 symphysis pubis to the spine of the ischium. The space between those two 

 fasciae is occupied by the levator ani and the fat and other contents of the 

 ischio-rectal fossa. 



a. The pelvic fascia is attached at the side superiorly for a short space to 

 the brim of the pelvis, but in front of the line of its osseous attachment it 

 inclines downwards towards the lower part of the symphysis pubis, following 

 the margin of the obturator internus muscle. Anterior to the spine of the 

 ischium, it lies between the obturator internus and the peritoneum, and at 

 the back part of the pelvis is continued as a thin membrane over the 

 pyriformis muscle and the sacral nerves, and is perforated by branches of 

 the internal iliac artery and vein. 



b. The recto-vesical fascia is the direct continuation of the pelvic fascia 

 downwards and inwards to the viscera, below the level of the white line 

 previously mentioned ; it descends, immediately in contact with the inner 

 surface of the levator ani muscle, to the prostate gland, the urinary bladder, 

 and the rectum. On reaching those organs it spreads over them, and 

 to some extent encases them. Close to the symphysis pubis, a short band 

 is directed backwards above the prostate gland, to the bladder, with which 

 it is intimately connected. A similar baud exists at the opposite side of 

 the symphysis pubis, and the two are separated by a narrow depression, in 

 which the dorsal veins of the penis lie, after entering the pelvis. The 

 bands in question are named the anterior true ligaments of the urinary 



