ABDOMINAL CAVITY 491 



orifice'of the vermiform process, which may be quite open, or 

 it may be partly guarded by a semilunar fold of mucous 

 membrane, the valve of the vermiform process. 



Colon Ascendens. The Ascending Colon passes upwards 

 from the caecum, in the iliac region, through the right lumbar 

 region to the right colic flexure in the right hypochondriac 

 region. It varies from about six to eight inches in length. It 

 is covered in front and at the sides by peritoneum which binds 

 it to the posterior wall of the abdomen. Occasionally it is 

 attached to the posterior abdominal wall by an ascending 

 meso-colon. Anteriorly it is either in contact with the 

 anterior wall of the abdomen or it is separated from the 

 abdominal wall by coils of small intestine and the right free 

 margin of the great omentum. 



Dissection. Turn the ascending colon upwards and clear away the fatty 

 areolar tissue from behind it, then note that it lies anterior to the upper part 

 of the iliacus, the crest of the ilium, and, above the crest, in front of the 

 fascia covering the quadratus lumborum and the medial part of the aponeur- 

 osis of origin of the transversus abdominis. It is separated from the 

 quadratus lumborum, however, not only by the anterior lamella of the 

 lumbar fascia, but also by the last thoracic, the ilio-hypogastric and ilio- 

 inguinal nerves. It is possible that the dissector will not be able to display 

 the last thoracic nerve at this stage of the dissection. 



Flexura Colica Dextra (O.T. The Hepatic Flexure of the 

 Colon). This flexure lies in the right hypochondrium below 

 and somewhat behind the anterior part of the lower surface of 

 the right lobe of the liver, to the right of the gall-bladder and 

 in front of the lower part of the right kidney. It is covered 

 by peritoneum except on its posterior surface, which is 

 attached to the kidney by loose areolar tissue. 



Colon Transversum (The Transverse Colon). The trans- 

 verse colon extends first downwards and forwards and then 

 upwards and backwards, from the under surface of the right 

 lobe of the liver, in the right hypochondriac region, to the 

 lower extremity of the spleen in the left hypochondriac 

 region. The lowest part of the curve usually crosses through 

 the upper half of the umbilical region, and a small but 

 acute secondary curve, which is developed upon the left 

 extremity of the main curve, lies against the medial border 

 of the upper part of the descending colon. In the greater 

 part of its extent it is enclosed in the posterior wall of the 

 omental bursa, its lower border being attached to the greater 

 curvature of the stomach by the greater omentum, whilst 



