922 A MANUAL OF ANATOMY 



The exact position of the ovary should receive special attention, andthecofpus 

 fimbriatum of the Fallopian tube, with its ovarian fimbria, is to be noted. 



The peritoneum is now to be stripped from the walls of the pelvis to 

 expose the pelvic fascia. On the lateral wall of the cavity the obturator 

 vessels and nerve are to be shown on their way to the obturator canal, 

 through which they pass. The pelvic fascia is then to be carefully examinea. 

 This fascia will be seen to line the lateral wall, where it covers the obturator 

 internus, and the posterior wall, where it forms the fascia of the pyriformis. 

 To see it in front, the bladder must be drawn well backwards. The lining 

 portion of the fascia is called the parietal pelvic fascia. To study it more fully 

 the dissector should remove a large part of the os innominatum by means of 

 the following cut : place the saw over the back part of the iliac crest and over 

 the pubic bone, keeping as near as possible to the pelvic brim, but external to it. 

 The bone is now to be sawn downwards in such a manner as to remove a 

 large part of the tuber ischii, but the great and small sciatic notches are to be 

 avoided. The obturator externus muscle is then to be carefully removed 

 from the outer surface of the obturator membrane, and the obturator artery 

 is to be shown in two branches, which form a loop upon the membrane round 

 its circumference. The obturator membrane is then to be removed, which 

 will expose a portion of the obturator internus. 



When this part of that muscle is taken away, a good view of the parietal 

 pelvic fascia from the outside will be obtained through the obturator fora- 

 men. The thickened portion of the fascia, known as the white line, is to be 

 observed extending from near the lower part of the symphysis pubis to the 

 spine of the ischium. On looking deeply into the pelvic cavity, the bladder 

 having been well displaced to one side, the parietal pelvic fascia, along the 

 white line, will be seen to send inwards its visceral layer, and the portion 

 of the parietal fascia below the white line will be seen, from the perineal 

 point of view, to line the outer wall of the ischio-rectal fossa, where it 

 contains Alcock's canal. From the under aspect of the white line the levator 

 ani muscle arises, and immediately below this the parietal pelvic fascia gives 

 off the anal fascia, which covers the perineal surface of the levator ani. The 

 dissector will now understand what structures separate the pelvic cavity, on 

 either side of the bladder, from the ischio-rectal fossa, this partition being 

 formed, from above downwards, by the visceral pelvic fascia, the levator ani, 

 and the anal fascia. 



At the upper part of the obturator foramen the parietal pelvic fascia should 

 be shown, on the side not yet dissected, to join the upper border of the 

 obturator membrane over the obturator internus muscle, thus converting the 

 obturator groove on the under surface of the superior pubic ramus into 

 a fibro-osseous tunnel, called the obturator canal. Through this canal the 

 obturator vessels and nerve will be seen to pass, and it will be evident that the 

 obturator artery escapes from the pelvic cavity without piercing the parietal 

 pelvic fascia. As the parietal fascia is attached along the ischio-pubic ramus, 

 at either side, it is continued inwards until it meets with the urethra. This 

 portion of it, with its fellow, forms the postero-superior layer of the triangular 

 ligament. From the urethra the fascia is continued backwards over the 

 anterior border of the levator ani to the prostate gland, where it becomes 

 continuous with the visceral layer of the fascia, which ensheathes that gland. 

 The visceral layer of the fascia is now to be followed inwards to the bladder, 

 rectum, and prostate gland. Opposite the vesicula seminalis it divides into 

 an upper or vesical, a middle or recto-vesical, and a lower or rectal layer, the 

 vesical layer forming the lateral true ligament of the viscus. Opposite the 

 prostate the visceral fascia divides into prostatic, recto-prostatic, and rectal 

 layers. In the female the visceral fascia divides into four layers, namely, 

 vesical, vesico- vaginal, recto-vaginal, and rectal. The bladder being pulled 

 well backwards, two stout bands of the visceral pelvic fascia will be seen to 

 extend from the lower part of the body of each pubic bone over the anterior 

 surface of the prostate gland to the bladder. These constitute the anterior 

 true ligaments of the bladder, and each will be found to contain some of its 

 external longitudinal muscular fibres. Between these two ligaments a well- 



