Chap, xvii.] ABDOMINAL VISCERA. 349 



from the region of the umbilicus to the pelvis. The 

 caecum is at first situated within the umbilicus, and then 

 ascends in the abdomen towards the left hypochon- 

 drium. It next passes transversely to the right hypo- 

 chondrium, and then descends into the corresponding 

 iliac fossa. It may be permanently arrested at any part 

 of its course. Thus the caecum may be found about the 

 umbilicus, or in a congenital umbilical hernia, or in the 

 left hypochondriac region (the ascending and trans- 

 verse parts of the colon being absent), or it may be 

 found in the right hypochondrium, the ascending 

 colon only being unrepresented. The whole of the 

 large intestine has at one time an extensive mesentery, 

 and in some rare cases this condition may persist 

 throughout life. 



Lumbar colotomy. The operation so named 

 consists in opening the colon in the loin behind the 

 peritoneum, for the purpose of establishing an arti- 

 ficial anus. The operation is performed, when possible, 

 upon the left side, in preference to the right, inasmuch 

 as the descending colon is nearer to the anus. The 

 position of the descending colon in the loin may be 

 represented by a line drawn vertically upwards from 

 a point half-an-inch behind the centre of the iliac 

 crest. In performing left lumbar colotomy an ink line 

 may be drawn vertically upwards from the centre of 

 the crest of the ilium. It will hit the outer end of 

 the last rib. An incision is made across the centre of 

 this line parallel to the last rib, and so planned that 

 the centre of the incision corresponds to the centre of 

 the line. The superficial tissues having been incised, 

 the following structures are then divided in layers in 

 the following order : (1) The latissimus dorsi and 

 external oblique nmscles to an equal extent. (2) The 

 internal oblique in the entire length of the incision. 

 (3) The fascia lumborum, with a few of the most 

 posterior fibres of the transversalis muscle. (4) The 



