1016 THE ORGANS OF DIGESTION. 



at the fourth lumbar vertebra into its two primitive iliacs. A little to the right 

 is the inferior vena cava, having just received the two common iliac veins. It 

 also receives, behind the descending and ascending part of the duodenum, the 

 renal veins the right on the level of the lower part of the second lumbar verte- 

 bra, and the left a little higher on the level of the upper part of the same vertebra, 

 having passed in front of the aorta. 



The superior hepatic curve of the duodenum rests on the vena cava at the 

 first lumbar vertebra right side. The descending portion covers about the two 

 external thirds of the anterior surface of the vena cava and the right renal 

 vessels. 



The horizontal portion of the duodenum in the U-form applies itself in one 

 part to the vena cava, and in another to the aorta, and sometimes passes over the 

 common iliacs. In the duodenum in the V-form the inferior angle lies upon the 

 vena cava to the right of the aorta, then the ascending portion crosses the aorta 

 sharply, from right to left, then borders it on the left and crosses the left renal 

 vein and ends in the duodeno-jejunal angle. 



The ascending portion in the U-form runs along the left surface of the aorta 

 and finally over the left renal vein as the above. 



(3) Relations to the Lumbar Column. By fixing the duodenum with pins 

 while in situ, Jonnesco examined thirty subjects and found that the first portion 

 of the duodenum lies to the right of the first lumbar vertebra. Its pyloric end 

 in the median line is on the level of the inferior extremity of this vertebra, and 

 it is directed up to the right and backward to reach the upper border of the 

 same vertebra. 



The pre-aortic portion, or inferior angle, reaches a variable point; in children, 

 the superior border of the fourth lumbar, or the disk between it and the third. 

 In adults with the duodenum in U-form, this pre-aortic portion moulds itself 

 over the convexity of the fourth lumbar vertebra in 12 out of 20 cases. In some 

 cases it passes over the fifth vertebra. In the duodenum in V-form the inferior 

 angle applies itself most often to the right of the column, and the lower border 

 of the fourth lumbar vertebra, in 5 out of 8 cases. Again it may go to the side 

 of the fifth lumbar three times in 8 cases. 



There may be three types : a high type, corresponding to the superior border 

 of the fourth, or articulation between it and the third, seen in the child ; middle 

 type, to the body of the fourth lumbar ; lotv type, to the body of the fifth lumbar, 

 confined almost wholly to the V-type. 



The duodeno-jejunal angle corresponds to the left of the vertebral column, 

 may be to the first lumbar vertebra (infantile type), or to the second (adult type 

 in U or V). In the first case the angle approaches the median line, in the latter 

 it is thrown to the side of the column. 



Relations of Duodenum in Detail. 



Superior Hepatic Curve, First Portion. 



Above and in front: 



Quadrate lobe of liver ; 

 Neck of gall-bladder; 

 Foramen of Winslow ; 

 Hepatic artery. 



Behind : 



Common bile-duct ; 



Vena portse ; 



Gastro-duodenal artery ; 



Vena cava inferior (at summit of curve) ; 



First lumbar vertebra (on the left). 



