THE PERITONEUM 



1265 



mesocolon (mesocolon ascendens) and a descending mesocolon (mesocolon descendens) 

 respectively. At the place where the transverse colon turns downward to form the 

 descending colon, a fold of peritoneum is continued to the under surface of the 

 Diaphragm opposite the tenth and eleventh ribs. This is the phrenocolic ligament 

 (ligamentum phrenicocolicum)', it passes below the spleen, and serves to support 

 this organ, and therefore it has received the name of sustentaculum lienis. 



The transverse mesocolon (mesocolon transversum) (Fig. 9S8) is a broad fold, 

 which connects the transverse colon to the posterior wall of the abdomen. It is 

 formed by the two posterior layers of the greater omentum, which, after separating 

 to surround the transverse colon, join behind it, and are continued backward to the 

 vertebral column, where they diverge in front of the anterior border of the pancreas. 

 This fold contains between its layers the vessels which supply the transverse colon. 



The sigmoid mesocolon (mesocolon sigmoideum) (Fig. 988) is the fold of peri- 

 toneum which retains the sigmoid flexure in connection with the pelvic wall. 

 Its line of attachment forms a V-shaped curve, the apex of the curve being placed 

 about the point of division of the left common iliac artery. The curve begins 

 on the inner side of the left Psoas, and runs upward and backward to the apex, 

 from which it bends sharply downward and inward, and ends in the mesal plane 

 at the level of the third sacral segment. Between the two layers of this fold run 

 the sigmoid and superior hemorrhoidal vessels. 



t 



INFERIOR 



MESENTERIC 



VEIN 



SUPERIOR 

 DUODENAL 

 FOLD 



SUPERIOR 

 DUODENAL 

 FOSSA 



INFERIOR 



DUODENAL 



FOSSA 



INFERIOR 



DUODENAL 



FOLD 



LEFT 



COLIC 



ARTERY 



FIG. 989. Superior and inferior duodenal fossae. (Poirier and Charpy.) 



The mesoappendix or mesentery of the vermiform appendix (mesenteriolum pro- 

 cessus vermiformis] (Fig. 992) is a double fold of peritoneum derived from the 

 left leaf of the mesentery. In the majority of cases it is triangular in shape and 

 usually extends along the entire length of the appendix. Between its two layers 

 lie the appendicular artery (Fig. 1037), a branch of the ileocolic artery, some 

 connective tissue, and lymph vessels and nerves. 



The appendices epiploicae are small pouches of the peritoneum filled with fat 

 and situated along the colon and upper part of the rectum. They are chiefly 

 appended to the transverse colon. 



Retroperitoneal Fossae. In certain parts of the abdominal cavity there are 

 recesses of peritoneum forming culs-de-sac or pouches, which are of surgical inter- 

 est in connection with the possibility of the occurrence of retroperitoneal hernia. 

 One of these is the lesser sac of the peritoneum (Figs. 980 and 982), which may be 

 regarded as a recess of peritoneum through the foramen of Winslow, in which 

 a hernia may take place, but there are several others, of smaller size, which require 

 mention. 



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