The Intestines. 237 



Lumbar Colotomy is not performed now as often as 

 formerly, being replaced by iliac colotomy, since the dan- 

 ger of opening the peritoneum is now almost nil, but, 

 when for any reason this operation is justified, the guide 

 to the incision is the normal situation of the colon. This 

 may be represented, posteriorly, by a line drawn upwards 

 from a point one half inch internal to the middle of the 

 crest of the ilium, i.e., half an inch internal to a point mid- 

 way between the anterior and the posterior superior spin- 

 ous processes of the ilium. The following description has 

 been synopsized from Treves' Operative Surgery : "The 

 incision in lumbar colotomy may be made parallel to the 

 last rib, or in an oblique direction from the anterior supe- 

 rior spinous process to the angle of junction of the last 

 rib with the erector spinse muscle. After section of the 

 skin and fasciae, the external oblique and the latiss.dorsi 

 muscles are exposed and divided and the internal oblique is 

 brought into view. On dividing and retracting its fibres 

 the transversalis muscle and the fascia lumborum are 

 seen, and after section of these, the transversalis fascia 

 and the outer edge of the quadratus lumborum present 

 themselves, and the former being incised, the subperiton- 

 eal fat is now reached. If the colon does not present 

 itself it must be sought for, and one of the best guides to 

 it is the feeling communicated when the bowel is picked 

 up between the finger and thumb. If sight, only, were 

 relied on, there would be a possibility of mistaking the 

 subperitoneal fat for bowel, since the former is at times 

 arranged in strata separated by distinct layers of fascia. 

 If the colon still remain undiscovered, the index finger 

 should be inserted into the wound and the angle of junc- 

 tion between the psoas and the quadratus lumborum mus- 

 cles sought for, as it is towards this situation that the un- 

 covered part of the colon presents. If the kidney be felt, 

 the bowel will lie in front of it." 



