382 THE ABDOMEN AND PELVIS 



necessary, the lower part of the sacrum may be removed, but 

 the bone must be divided below the third pair of sacral foramina, 

 otherwise incontinence of urine and faces will result. 



The middle sacral artery (p. 370) is ligatured, and then, by 

 dissection with the fingers, the levator ani is separated from 

 the rectum on each side and the visceral layer of the pelvic fascia 

 is torn through as it passes from the upper surface of the muscle 

 on to the gut. In the region of the rectal ampulla, the fingers 

 may be gradually insinuated round the bowel, passing between 

 it and the base of the bladder and prostate. One blade of a 

 pair of scissors is next inserted above the levator ani at the 

 point where the median incision meets the incision round the 

 anus, and, with the other blade in the circular incision, the 

 wound is deepened around the anal canal. In this process 

 the levatores ani are divided until their anterior free borders are 

 reached on the antero-lateral aspect of the rectum. Anteriorly, 

 the recto-urethralis and the attachment of the external sphincter 

 to the central point of the perineum require to be cut through, 

 and the former must be divided as close to the rectum as possible, 

 in order to avoid injuring the membranous part of the urethra. 



As a result of this step, the anal canal and the lower two 

 inches of the rectum can be dragged downwards and a further 

 inch can be freed, with the fingers and with scissors, from its 

 anterior peritoneal covering. 



Some difficulty will be experienced in dragging down more 

 of the rectum, as it is anchored in place by the cellular tissue 

 in which the middle hsemorrhoidal vessels are embedded. These 

 " lateral ligaments " having been clamped and divided, the 

 bowel is only held by its peritoneal covering. The peritoneum is 

 incised transversely, close to the rectum, along the recto-vesical 

 line of reflexion. As the bowel is gradually pulled down, the 

 peritoneum is incised along each side and the branches of the 

 superior hsemorrhoidal artery are secured as they are met with. 



After the bowel has been mobilised for some distance above 

 the diseased area, its peritoneal surface is stitched to the cut 

 recto-vesical peritoneum. Just below the sutured area, the 

 bowel is ligated and cut through, and it can then be lifted away. 

 The proximal cut end may be surrounded with a purse-string 

 suture and invaginated, the usual procedure in closure of the 

 large intestine. 



This operation produces less shock than some of the more 

 extensive operations which provide the patient with a new 



