LITHOTOMY-PELVIC FASCIA. 849 



in the operation for lithotomy, in its passage forwards to the bulb. The acces- 

 sory pudic may be divided near the posterior border of the prostate gland, if 



Fig. 461. Side View of the Pelvic Viscera of the Male Subject, showing the Pelvic and 



Perineal Fasciae. 



this is completely cut across: and the prostatic veins, especially in people 

 advanced in life, are of large size, and give rise, when divided, to troublesome 

 hemorrhage. 



PELVIC FASCIA. 



The Pelvic Fascia (Fig. 462) is a thin membrane which lines the whole of 

 the cavity of the pelvis, and is continuous with the transversalis and iliac 

 fascia3. It is attached to the brim of the pelvis for a short distance at the side 

 of the cavity, and to the inner surface of the bone round the attachment of the 

 Obturator Internus. At the posterior border of this muscle, it is continued 

 backwards as a very thin membrane in front of the Pyriformis muscle and 

 sacral nerves, behind the branches of the internal iliac artery and vein which 

 perforate it, to the front of the sacrum. In front, it follows the attachment of 

 the Obturator Internus to the bone, arches beneath the obturator vessels, com- 

 pleting the orifice of the obturator canal, and at the front of the pelvis is 

 attached to the lower part of the symphysis pubis ; being continuous below 

 the pubes with the fascia of the opposite side so as to close the front part of 

 the outlet of the pelvis, blending with the posterior layer of the triangular 

 ligament. At the level of a line extending from the lower part of the sym- 

 physis pubis to the spine of the ischium, is a thickened whitish band ; this 

 marks the attachment of the Levator Ani muscle to the pelvic fascia, and cor- 

 responds to its point of division into two layers, the obturator and recto-vesical. 



The obturator fascia descends and covers the Obturator Internus muscle. It 

 is a direct continuation of the pelvic fascia below the white line above men- 

 tioned, and is attached to the pubic arch and to the margin of the great sacro- 

 54 



