THE PERITONEUM 



1159 



1. Duodenal Fossse (Figs. 1041, 1042). Three are fairly constant, viz. : (a) The 

 inferior duodenal fossa, present in from 70 to 75 per cent, of cases, is situated 

 opposite the third lumbar vertebra on the left side of the ascending portion of 

 the duodenum. Its opening is directed upward, and is bounded by a thin sharp 



Inferior 



mesenteric 



vein 



Duodenojejunal 

 fold 



Superior 

 duodenal fossa 



Inferior 

 duodenal fossa 



Duodenomesocol ic 

 fold 



Left colic artery 

 FIG. 1041. Superior and inferior duodenal fossae. (Poirier and Charpy.) 



fold of peritoneum with a concave margin, called the duodenomesocolic fold. The 

 tip of the index finger introduced into the fossa under the fold passes some 

 little distance behind the ascending portion of the duodenum. (6) The superior 

 duodenal fossa, present in from 40 to 50 per cent, of cases, often coexists with the 

 inferior one, and its orifice looks downward. It lies on the left of the ascending 



Duodenum 



Eight 

 duodeno- 

 mesocolic 



fold 



Inferior 

 mesenteric vein 



Left 



duodenomesocolic 

 fold 



Left colic artery 



fJNRSS 



Inferior mesenteric artery 

 FIG. 1042. Duodenojejunal fossa. (Poirier and Charpy.) 



portion of the duodenum, in front of the second lumbar vertebra, and behind a 

 sickle-shaped fold of peritoneum, the duodenojejunal fold, and has a depth of about 

 2 cm. (c) The duodenojejunal fossa exists in from 15 to 20 per cent, of cases, 

 but has never yet been found in conjunction with the other forms of duodenal 



