DEVELOPMENT OF THE INTESTINES 433 



intestines attached through its mesentery to the duodenum we may 

 look upon as belonging in the main to the primitive duodeno- 

 jejunal loop of the small intestines; that portion attached to the 

 left and below where the superior mesenteric artery crosses the 

 duodenum we may look upon as belonging in the main to the 

 umbilical coils of the intestines. The primitive relations of the 

 mesentery of these two portions of the small intestines is shown in 

 figure 7. They undoubtedly vary, to some extent inversely, in 

 development in different bodies. The duodeno-jejunal coils cor- 

 respond in the main with the transverse coils in the adult, described 

 by Henke, the umbilical coils to the vertical coils. 



Exceptionally good illustrations of the attachment of the mesen- 

 tery of the jejunum and ileum have been furnshed by Stopnitzki.^ 



He has pictured 'high forms' running nearly horizontally to 

 the right from the base of the superior mesenteric artery; low forms 

 bowing well to the left of the usual line of attachment and various 

 intermediate forms. He shows the cut base of the mesentery to 

 be widest in the region of the main trunk of the superior mesenteric 

 artery and to taper off from here toward the colic extremity of the 

 ileum and the jejunal end of the duodenum; He has divided the 

 base of the mesentery into twenty parts and the intestinal margin 

 into twenty parts and compared the distance between the corre- 

 sponding segments. He found that, as a rule, the mesentery showed 

 two regions of maximum width, one near the seventh to eighth 

 and one near the sixteenth to seventeenth of the twenty segTnents, 

 counting from the duodenal end. In only two out of every 

 twenty-five cases was there a marked departure. In these two 

 cases the mesentery was widest about the middle of the distance 

 between the two extremities of the small intestine. To what 

 extent the proximal and distal halves of the free small intestine, 

 each with its mesentery longest toward the junction of the distal 

 with the middle third, correspond with the parts of the intestine 

 the coils of which originated respectively within the umbilical cord 

 and within the abdominal cavity we have at present no data. 



" Untersuchungen ziir Anatomic i^los menschlichen Darmes, Internat. Monat- 

 schr. f. Anatomie u. Physiologie, Bd. 15, p. 219, 1898. 



