Abdominal Vessels and Regions. 265 



are divided, the peritoneum is stripped from the iliac fas- 

 cia and the common iliac artery is identified, and, on fol- 

 lowing this vessel upwards, the aorta is felt pulsating. 

 This vessel should be well bared before ligating it, so as 

 to avoid the sympathetic plexus of nerves that overlies it. 



The inferior vena cava is a little longer than 

 the aorta, to the right of which it lies, and is formed by the 

 junction of the two common iliacs, which unite on the right 

 side of the intervertebral substance between the fourth 

 and fifth lumbar vertebrae. Below, this vein is on a plane 

 posterior to the artery, but above, it is separated from this 

 vessel by the right crus, and, near the diaphragm, lies an- 

 terior to it. 



Contents of the Abdominal Regions. The 

 division of the abdomen into nine regions by means of two 

 vertical and two horizontal planes has already been con- 

 sidered, but, in place of naming the different viscera in 

 each region, we prefer to illustrate their relative situations 

 from a pathological standpoint, as. follows : 



A TUMOR SITUATED IN THE RIGHT HYPOCHONDRIAC REGION 

 MAY BE : 



A dilated gall-bladder. , 



A tongue-like projection of the right lobe of the liver. 



A movable or diseased kidney. 



Fcecal impaction in the hepatic flexure of the colon. 



IN THE EPIGASTRIC REGION IT MAY BE : 



A dilated gall-bladder (the vertical plane cuts this 

 structure). 



A tumor involving the caudate, quadrate, Spigelian or 

 the left lobe of the liver. 



A carcinoma or cyst of the pancreas. 



A carcinoma of the middle or pyloric end of the stom- 

 ach, or of the first, second, or the end of the third portions 

 of the duodenum. 



