450 



THE MUSCLES AND FASCIAE 



sheathes the nerves as they emerge from these foramina. Anterior to its iliopectineal 

 attachment the pelvic fascia sinks in its attachment below the brim of the pelvis. 

 It arches below the obturator vessels and nerves, completing the obturator canal, 

 and at the front of the pelvis the line of attachment is depressed distally on the 

 posterior surface of the os pubis, so that at the symphysis it lies just above the 

 inferior border of this bone. From this line of attachment the posterior part 

 is prolonged outward on the Obturator internus into the gluteal region. The 

 middle portion descends on the visceral surface of the Obturator internus to become 

 attached to the falciform process of the great sacrosciatic ligament. Because 

 of this relation with the Obturator internus this part is called the Obturator fascia. 

 The part attached to the body of the pubis descends to be attached to the ischio- 

 pubic ramus, and here becomes blended with the base of the triangular ligament. 

 From the ischiopubic ramus it is continued onward behind the Compressor 



Obturator fascia. 



Internal pudic vessels 

 and nerve. 



Tuberosity of 

 ischium. 



FIG. 342. A transverse section of the pelvis, showing the pelvic fascia from behind. 



urethrae muscle across the pubic arch, to be continuous with the fascia of the 

 opposite side. Here it takes a special name, the deep layer of the triangular 

 ligament (fascia diaphragmatis urogenitalis superior). This part of the fascia 

 is perforated by the urethra; a portion of it turns backward around the anterior 

 extremity of the Levator ani muscle to join the visceral layer next to be considered. 

 At the level of a line extending from the back part of the symphysis pubis to 

 the spine of the ischium is a thick, whitish band termed the white line (arcus 

 tendineus). Above this line the fascia lies in contact with the peritoneum and 

 belongs to the pelvic cavity. Below this line the obturator fascia has to do with 

 the ischiorectal space. The pudic vessels and nerves cross this area enclosed in a 

 special sheath (Alcock's canal). At the white line the obturator fascia gives off 

 a special layer to the pelvic viscera (fascia endopelvina); where these two layers 

 diverge partly arises the Levator ani. The visceral layer lies superior (cephalad) 

 to the Levator ani. Traced forward it is seen to be attached to the posterior 



