180 PROFESSOR CHRISTOPHER ADDISON. 



IV. Shape of the Duodenum. 



The direction of the first part of the duodenum varies chiefly 

 with the position of the pylorus. In case 16, in which it was 

 horizontal, the pylorus was pulled across the middle line by 

 the stomach displaced to the left by the liver. 



The first part of the duodenum passed almost directly back- 

 wards in cases 2, 4, 8, 15, 18, 20, 21, 25, 27, 29, 32, 34, 

 and 38. 



The first and fourth parts of the duodenum are those most 

 subject to variation. The first from displacements ; the fourth 

 from abnormalities, connected chiefly with its special position 

 in regard to the development of the peritoneal folds in its 

 neighbourhood. 



The general shape of the duodenum accorded with the usual 

 descriptions. No attempt has been made to classify it under, 

 for instance, V-shaped or U-shaped varieties. 



The following cibnormal duodena call for special attention : — 

 In case 7 (see fig. 9) the duodenum was pushed down and to 

 the left by a displaced liver ; the lower left portion of the head 

 of the pancreas (corresponding to the part that is sometimes 

 spoken of as the lesser pancreas) extended across the front of the 

 fourth part of the duodenum towards the left into the root of 

 the mesentery for 3 cm. beyond the duodenum. The mesen- 

 teric vessels emerged from beneath the body of the pancreas as 

 usual and passed in front of this extended piece of the pancreas 

 into the mesentery. The third or transverse part of the duo- 

 denum was very reduced in length, the fourth, or ascending 

 part, being situated on the right side of the vertebral column. 

 It is difficult to believe that the condition had been produced 

 by displacement of the pancreas over the duodenum by the 

 descent of the liver. It is more likely that it represents a 

 duodenum of a simple bend like that of the bonnet monkey 

 (Treves, 15), with the pancreas in an approach to the normal 

 position in man. 



In case S the first part of the jejunum had a sharp bend 

 downwards lying in a groove between a mesocolic fold, ex- 

 ternally, and the fourth part of the duodenum internally. 



