722 



A MANUAL OF ANATOMY 



The para-duodenal fossa is situated a little to the left of the terminal 

 part of the duodenum. It is bounded on the left side by a faint fold of peri- 

 toneum, called the inferior mesenteric fold, which is produced by the inferior 

 mesenteric vein. 



The retro-duodenal fossa is si uated behind the terminal part of the 

 duodenum. 



Duodeno-jejunal Fossa.— This fossa is situated on the left side of the 

 duodeno-jejunal flexure, and leads upwards and towards the left side. It is 

 bounded by two free portions of peritoneum, called the duodeno-raesocolic 

 folds, and it has the pancreas above, the left kidney on the left, and the aorta 

 on the right. It is of small size, and may admit the tip of the httle linger. 

 It is said to be present in from 15 to 20 per cent, of cases. 



Perl-Caecal Fossae. — These fossae are three in number, namely, ileo-coHc, 

 ileo-caecal, and retro-caecal, 



Superior Duodenal Fossg 



Inferior Duodenal Fossa 



Fig. 307. — Duodenal Foss.^. 



The ileo-colic fossa is situated in the angle between the termination of the 

 ileum and the commencement of the ascending colon, in front of the adjacent 

 part of the mesentery proper. It opens inwards, and is bounded in front 

 by a portion of the peritoneum, called the ileo-colic fold, which is produced by 

 the anterior caecal artery; behind, by the mesentery proper; below, by the 

 ileum ; and, on the right side, by the commencement of the ascending colon. 

 In size and depth the fossa is small. 



The ileo-csecal fossa is situated in the angle of junction of the ileum and 

 caecum, and opens downwards and inwards. It may extend upwards for a 

 variable distance behind the ascending colon, and sometimes is capable of 

 admitting two fingers. It is bounded anteriorly and infcriorly by a portion 

 of peritoneum, called the ileo-csecal told (bloodless fold of Treves) ; posteriorly, 

 by the meso-appendix; externally, by the caecum; and superiorly, by the 

 posterior aspect of the terminal part of the ileum and the inferior layer of 

 the mesentery proper. The importance of this fossa consists in the fact that 

 it often contains the vermiform appendix, or a portion of it. 



The retro-csecal fossa is situated behind the caecum, on the outer side of 

 the meso-appendix. It may extend upwards for a variable distance behind 

 the ascending colon, and is sometimes divided into an external and internal com- 

 partment. It occasionally contains the vermiform appendix, or a portio^i of it. 



Intersigmoid Fossa. — This fossa is of rare occurrence in the adult, but 

 is frequently present in early infancy. It is situated on the left side of the 

 pslvic meso-colon near the bifurcation of the left common iliac artery, and 



