194 SURGICAL ANATOMY OF 



anteriorly and laterally, and is for that reason selected 

 for the operation of opening the colon in the left loin 

 (Amussat). 



That portion of the spinal column which is inclosed 

 between these regions, has upon its anterior surface the 

 crura of the diaphragm, covered by peritoneum and sub- 

 peritoneal fat and fascia, the vena cava ascendens, ab- 

 dominal aorta, and on either side the chain of the sym- 

 pathetic, the thoracic duct, the receptaculum chyli, vena 

 azygos major, and a large number of lymphatic ganglia. 



Lumbar Colotomy. The colon may be reached either 

 by a transverse incision (Amussat), or by a longitudinal 

 one (Hilton, Callisen). 



Structures divided in Amussafs Operation. A point is 

 taken midway between the crest of the ilium and the 

 last rib at the outer edge of the erector spinae, varying 

 in length according to the development of the individual, 

 and is directed outwards, at first dividing the integu- 

 ments, the aponeurotic origin of the latissimus dorsi, and 

 some few fibres of the external oblique ; next the origin 

 of the internal oblique and transversal is, and a portion 

 of the quadratus lumborum and its fascial investment. 

 After the transversalis fascia has been divided, a quantity 

 of loose cellular tissue and fat is seen, which, being 

 scratched through, exposes the colon. During life, how- 

 ever, the distension is generally so great that the bowel 

 bulges into the wound. 



In the vertical incision, which is made about four 

 inches or so external to the spinous processes of the ver- 

 tebra?, the structures divided would be, the integument, 

 the aponeurotic origin of the latissimus dorsi, the origin 

 of the internal oblique, tendon, transversalis and trans- 



