THE SMALL INTESTINE. 



407 



stomach, it does not tend to involve the duodenum. This is probably due to the 

 lymph stream from the pylorus running toward the stomach and away from the 

 duodenum. The duodenum is also of interest in consequence of its intimate relation 

 to the biliary passages and gall-bladder as well as to the pancreas and its ducts. 

 Inflammations, such as accompany gall-stones, frequently give rise to adhesions, to 

 relieve which operations are performed. The second portion of the duodenum is 

 sometimes opened in order to extract a biliary calculus impacted in the ampulla of 

 Vater at the mouth of the common bile-duct. The upper portion of the duodenum 

 in Finney's operation for pyloroplasty is slit down from the strictured pylorus and 

 sewed to a corresponding slit in the stomach, thus making a large communication 

 between the duodenum and the stomach and eliminating the stricture. 



In shape the duodenum resembles a horseshoe. It begins on the right side 

 of the body of the first lumbar vertebra and ends on the left side of the body of the 

 second lumbar vertebra. At its commencement it is suspended from the liver by 



Common bile duct 



First portion of 

 duodenum 



Second portion 

 of duodenum 



Pancreas 



Hepatic flexure 

 of colon 



Pylorus 



Splenic flexure 

 of colon 



Transverse 

 mesocolon 

 Duodenojejunal 

 flexure 



Fourth portion of 

 duodenum 



Third portion of duodenum 



Mesentery 

 FIG. 419. The duodenum, showing its course and relation to the surrounding organs. 



the duodenohepatic ligament, which is the free edge of the gastrohepatic omentum 

 in which run the hepatic artery, portal vein, and common bile-duct. 



The duodenum is composed of four portions. The first portion (superior) 

 begins at the pylorus and ends at the neck of the gall-bladder. It is about 5 cm. (2 

 in. ) long, and runs backward along the body of the first lumbar vertebra. The 

 second portion (descending) is about 10 cm. (4 in. ) long, and runs down the right 

 side of the bodies of the lumbar vertebrae to the lower border of the third. The 

 third portion (variously called ascending, transverse, or inferior) runs diagonally 

 upward across the body of the third lumbar vertebra to its left side and then the 

 fourth portion ascends to the left side of the second, where it takes a sharp turn and 

 is continued as the jejunum (Fig. 419). 



Relations. First portion: Above and in front are the quadrate lobe of the 

 liver and the gall-bladder; below is the pancreas; and behind, from left to right, lie 

 the gastroduodenal artery, the portal vein, the common bile-duct, and the vena cava. 



Second portion :' In front is the liver, the neck of the gall-bladder, and the 

 transverse colon. Behind are the renal vessels, ureter, right kidney, and psoas 

 muscle. To its inner side lie the pancreas and vena cava. The common bile-duct 

 runs on the inner side between the duodenum and the pancreas; at the middle of this 

 portion of the duodenum the bile-duct joins with the pancreatic duct to empty into 

 the duodenum through the ampulla of Vater, about 10 cm. (4 in. ) from the pylorus. 



