CHAPTER XXIII. 

 THE INTESTINES. 



ANATOMY. NERVOUS REFLEXES. 



THE MESENTERY. APPENDICITIS. 



RELATIONS. OBSTRUCTION. 



LANDMARKS. OPERATIVE WORK. 



The Small Intestine averages in length about 

 twenty- two and a half feet in the male, and about twenty- 

 three and a half in the female, and is composed of three 

 parts, the duodenum, the jejenum and the ileum. The 

 duodenum is from ten to twelve inches in length and from 

 one and a half to two inches in width, and is either U, V 

 or annular-shaped. It is divided into four portions. The 

 first portion passes transversely, when the stomach is 

 empty, but posteriorly, when it is distended, and is direct- 

 ed towards the upper border of the first lumbar vertebra. 

 Relations : This part lies under the gall bladder and the 

 quadrate lobe of the liver; forms the lower boundary of 

 the foramen of Winslow ; has behind it the portal vein and 

 the hepatic vessels ; is situated above the pancreas and is 

 almost entirely surrounded by peritoneum. The second 

 or descending portion lies on the right of the vertebrae ex- 

 tending from the upper border of the first lumbar to the 

 lower border of the third and occasionally the fourth 

 lumbar vertebra, and is about three inches in length. Re- 

 lations : It has in front of it the liver, the transverse colon 

 and the meso-colon ; behind, are the inner border of the 

 right kidney, the renal vessels, the vena cava and the 

 common bile duct, the latter running downwards, near 

 the inner border, to join the pancreatic duct in the sub- 

 stance of the inner wall of this second portion of the duo- 

 denum, a little below its middle. This part of the duo- 



