SMALL INTESTINES. 



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passes nearly transversely across the front of the spine, terminating in the jeju- 

 num on the left side of the second lumbar vertebra. Hence the duodenum has 

 been divided into three portions : ascending, descending, and transverse. 



The first, or ascending portion (Fig. 401), about two inches in length, is free, 

 movable, and nearly completely invested by the peritoneum. It is in relation, 

 above and in front, with the liver and neck of the gall-bladder ; behind, with 

 the right border of the lesser omentum, the hepatic artery and duct, and vena 

 portae. This portion of the intestine is usually found, after death, stained with 

 bile, especially on its anterior surface, 



Fig. 401. Relations of the Duodenum. (The Pancreas has been cut away, except its head.) 



The second, or descending portion, about three inches in length, is firmly fixed 

 by the peritoneum and pancreas. It passes from the neck of the gall-bladder, 

 vertically downwards, in front of the right kidney, as far as the third lumbar 

 vertebra. It is covered by peritoneum only on its anterior surface. It is in 

 relation, in front, with the right arch of the colon and the meso-colon ; behind, 

 with the front of the right kidney ; at its inner side is the head of the pancreas, 

 and the common choledoch duct. The common bile duct and the pancreatic duct 

 perforate the inner side of this portion of the intestine obliquely, a little below 

 its middle. 



The third, or transverse portion, the longest and narrowest part of the duo- 

 denum, passes across the front of the spine, ascending from the third to the 

 second lumbar vertebra, and terminating in the jejunum ou the left side of that 



