966 



THE ORGAXS OF DIGESTION 



The fourth part of the duodenum, or second ascending portion, ascends vertically 

 by the left side of the spine. This vertical portion — which is covered entirely iii 

 front and i)artly at the sides by peritoneum — is at least an inch in length (figs. 570, 

 571, and 572). The end of the duodenum is very firndy fixed in its place by the 

 muscidus suspensorius daodeni. This name has been given to a fibrous band that 

 contains, according to Treitz, some plain muscular fibres, and that descends to the 



Fig. 571.— The Diuukxum fkom behind. 



Portal vein 



COMMON BILE 

 DUCT 



FOURTH PART OF DUODENUM 



HEAD Of PANCREAS 



vertical part of the duodenum from the left crus of the diaphragm and the tissues 

 about the coeliac axis. 



Mr. Lockwood points out that this band is continued on, after being inserted 

 into the duodenum, between the layers of the mesentery. He suggests the name 

 of the * suspensory muscle of the duodenum and mesentery, ' and snys, ' together 

 Avith the other constituents of the root of the mesentery, it forms a band of con- 



FiG. 572. — The Fossa Duodeno-jejunalis. (Treves.; 

 '^R^^^svERSE colow 



THE DUODENAL 

 FOLD 



Inferior mesenteric 

 rein 



sidcrable strength, sufticicnt not only to support the weiglit of tlic intestines and 

 mesentery, but also to resist the pressure of the descent of the diaphragm.' 



In coimection with the termination of the duodenum may be mentioned the 

 fossa duodeno-jejunalis. It is formed as a pouch behind a fold of peritoneum. 

 Tliis fold runs from tlie parietal peritoneum, just to tlic left of the terminal or 

 fourth part of tlie duodenum, and is attaclicd in n vertical line to the anterior 



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