ARRANGEMENT OF THE FASCIiE OF THE PELVIS. 139 



opposite side, and is finally lost over the sphincter muscles at 

 the lower end of the bowel. Between the bladder and rectum 

 the descending layers of the two sides are joined together, and 

 in this way the front part of the rectal sheath is completed. 

 The intervening layer, in addition, gives a covering to the 

 vesiculae seminales in the male, and to the vagina in the female. 



The significance of the ' white line ' of the pelvic fascia has 

 given rise to much speculation, and since one of the most 

 obvious differences in the general anatomy of the fascia visceralis 

 in man and the orang-utan is the absence of this line in the 

 latter, the question arises whether its appearance is not due to 

 the exigencies of the upright posture, rather than to a mere 

 thickening or opacity of the parietal pelvic fascia, along which 

 a division or splitting into various layers is said to take 

 place. 



Professor Thane's^ account of the white line of the pelvic 

 fascia is as follows : — " There is seen on the upper surface of 

 the recto-vesical fascia a thickened band, which springs from 

 the pubis in common with the anterior true ligament of the 

 bladder, and passes backwards and outwards to the ischial spine, 

 thus strengthening the floor of the pelvic cavity, and assisting 

 materially in the support of the bladder. This is the so-called 

 white line of the pelvic fascia, and in its posterior part it corre- 

 sponds to the place of origin of the recto-vesical fascia from the 

 obturator fascia." 



According to Luschka,^ the white line is either an elongated 

 thickening or a duplication of the pelvic fascia, which projects 

 as a ledge into the pelvic cavity, and lies on the upper surface 

 of the levator ani, and his observations support the view that 

 there is no absolute connection between it and the origin of the 

 muscle. The muscular fibres are attached to the white line, 

 but only by connective tissue. 



Kollmann ^ observes that the appearance of the white line 

 may be associated with the reduction of the levator ani. In a 

 Llama calf which he dissected, the ventral part of the levator ani 

 (pubo-coccygeus) was wanting, but in its place he found a well- 

 defined tendinous arch, which extended from the symphysis 

 pubis to the tuber ischii. In this case the muscle appeared to 



1 Quain's Anatomy. ^ Luschka, loc. cit. ^ Kollmann, loc. cit. 



