Colotomy 331 



flexure through the anterior abdominal wall, and through that part of 

 the bowel which is covered with peritoneum. The operation is ex- 

 tremely simple, and, as the bowel is usually stitched to the skin wound, 

 and is there allowed to become glued by adhesive inflammation before 

 it is opened, the risk of peritonitis is very slight 



A curved incision of about 3 in. is made in the iliac region with 

 the convexity towards the anterior superior iliac spine much as 

 for ligation of an iliac artery (p. 295). But after the two obliques, the 

 transverse muscle, and the transversal! s fascia have been divided the 

 peritoneum is opened and the sigmoid loop brought up ; it is easily 

 recognised. Before it is stitched to the abdominal wound all its slack 

 folds should be drawn down, so that the artificial anus may be made 

 in the highest part and the risk of subsequent prolapse of bowel may 

 be diminished. 



By drawing out a spur of the bowel evacuation can be completely 

 and permanently secured by the artificial opening ; unless this is done 

 merely a faecal fistula will be formed and much of the motions will 

 escape again per anum. 



Amussat's operation is best performed upon the left side, as ob- 

 struction in the large intestine is likely to be in the sigmoid flexure or 

 rectum ; thus the artificial anus is made much nearer the end of the 

 canal than when the colon is opened on the right side, and faecal ac- 

 cumulation is the more effectually obviated. Before operating, the 

 surgeon inflates the bowel through the rectum, so as to steady it and 

 to widen out the strip which is destitute of serous covering. He feels 

 for the last rib and the iliac crest and makes his incision through the 

 intervening space. 



A line is drawn up from \ in. behind the middle of the iliac crest 

 to the last rib, and a 4-in. or 5-in. incision is made across that line. 



The outer border of the erector spinae is easily made out, and the 

 incision is begun, or ended, just over it say i| to 2 in. from the spine. 

 (By the horizontal incision the lumbar arteries are avoided.) Skin and 

 fascia are divided, and the fleshy borders of the latissimus dorsi and 

 external oblique (figs, on pp. 303, 327) are notched ; the posterior part 

 of the fleshy internal oblique is freely incised on a director just as it 

 arises from the lumbar fascia, and the transversalis muscle, chiefly a 

 shining aponeurosis (fascia lumborum), though slightly fleshy at the front 

 of the wound, is opened up. Then the outer border of the quadratus 

 is bared, and, crossing from the front of it, the anterior division of the 

 last dorsal, or an upper lumbar nerve is seen. Next comes a quantity 

 of fat through which the surgeon carefully works with director and 

 forceps ; in front of this is the unimportant transversalis fascia, which 

 is to be carefully torn through. Then the lower end of the kidney is 

 felt, and the colon, which lies upon it, is traced down, and opened well 

 on its posterior and internal aspect. Unless the surgeon keep quite 

 to the back of the wound, he is apt to injure the peritoneum where it 



