ABDOMINAL VISCERA IN MAN. 171 



bends downwards, passing just under cover of the back part of the 

 eighth costal cartilage, and reaches its extreme right 1 inch 

 below E.F., nearly 3 inches from the middle line. It continues 

 downwards, passing slightly inwards to within half an inch of the 

 highest part of the iliac crest in the right lateral line ; then, 

 turning inwards, it crosses the middle line 1 inch above the 

 umbilicus and rather over 3 inches below E.F. Its terminal 

 part, the highest point of the duodeno-jejunal flexure, is 

 situated in the plane of E.F. about 1 inch to the left of the 

 middle line. 



Reference to fig. 3 b (Part I.) shows that, if a parallelogram 

 be constructed, having as its sides the middle line, E.F., the right 

 lateral line, and a line drawn transversely half-way between 

 E.F. and CD., the superior, external, and inferior sides of the 

 parallelogram practically bisect the first, second, and third 

 parts of the duodenum respectively, the fourth part inclining to 

 the left of the internal side of the parallelogram. 



II. Relations of the Duodenum to Adjoining Viscera. 



Birmingham (6) in his paper emphasises the point that in 

 his cast of the duodenum it passes to a considerable extent 

 on a sagittal plane. Very many of tliese cases illustrate the 

 same point. So that, when it is said that the highest point 

 of the first part of the duodenum is situated only 2 cm. 

 further outwards than the pylorus, it does not indicate neces- 

 sarily that the first part of the duodenum is only 2 cm. long, 

 for in many cases this part of the bowel passes almost directly 

 backwards. 



First Part. — Concerning the first part of the duodenum, it is 

 particularly to be noticed that in most cases it lies almost 

 wholly in a groove on the upper and anterior aspect of the 

 head of the pancreas — the aspect of the groove varying, of 

 course, with the direction of this part of the duodenum. 



Second Part. — The second part of the duodenum lies in a deep 

 groove along the outer or right border of the head of the pan- 

 creas. The lips of the groove frequently extend half-way across 

 the second part of the duodenum, the posterior one being com- 

 monly the larger. Cases 20, 25, and 30 presented the ex- 



