TOPOGRAPHY OF THE THORAX AND ABDOMEN 43 



most anatomists the duodenojejunal angle is at the level 

 of the second instead of the first lumbar vertebra. Jon- 

 nesco^ places the transverse portion across the fourth or 

 fifth lumbar vertebra and the pylorus and duodenojejunal 

 angle at the side of the first lumbar vertebra. 



The jejunoileum begins at the duodenojejunal angle 

 about 5 cm. to the left of the midplane at the level of the 

 first lumbar vertebra, and ends at the ileocolic valve about 

 3 cm. to the right of the midplane over the right end of the 

 disc between the fourth and fifth lumbar vertebrae. The 

 coils of this part of the intestine are so variable in position 

 and relations that they are not represented in the projec- 

 tions. The mesentery is attached to the posterior body 

 wall along a line nearly straight from the duodenojejunal 

 angle to the ileocolic valve. In the upper half this attach- 

 ment is to the front of the fourth portion of the duodenum. 

 In the lower half it is at first attached to the aorta, then to 

 the vena cava inferior and right common iliac vessels. 



THE LARGE INTESTINE 



The caecum lies in the right iliac fossa and extends as 

 far down as the promontory of the sacrum. Its apex is 

 about 4 cm. below the ileocolic valve. The latter is anterior 

 and to the right of the disc between the fourth and fifth 

 lumbar vertebrae, about 1 cm. below a line connecting the 

 highest points of the crests of the ilia and 3 or 4 cm. above 

 a line connecting the anterior superior iliac spines. 



The vermiform appendix arises from the posterior part 

 of the internal surface of the caecum about midway between 

 the ileocolic valve and the apex of the caecum, and extends 



^Jonnesco, T., Poirier, P. et Charpy,A., Traits d'anatomie humaine, 

 IV. 



