THE PERITONEUM. 991 



kind on the right side would press upon the right inguinal region ; if upon the 

 left side, would have an inclination to gravitate to the true pelvic cavity. At 

 the root, the right layer is continued into the lower layer of the transverse meso- 

 colon ; on both sides the layers continue themselves, one into the inner lamella 

 of the left colon and the other into that one of the right colon. The left layer 

 continues downward into the peritoneum, covering the lumbar vertebrae, which 

 passes over the promontory to the pelvic organs. 



The Omenta and Bursa Omentalis. 



The great omentum we have seen consists of four layers formed by an anterior 

 descending lamella of two and a posterior ascending lamella of two. It was 

 derived from the mesogastrium (Fig. 599). Its two middle layers (Fig. 606) con- 

 stitute the walls of the lesser sac and come from the right leaf of the mesogastrium; 

 its two superficial layers belong to the greater peritoneal cavity and come from the 

 left leaf of the mesogastrium. 



Only in foetal life could the first and second or third and fourth layers be 

 separated and only up to about the age of two years does the cavity exist between 

 the second and third layers. Before that age and sometimes in adults the cavity 

 of the great omentum can be distended by air introduced through the foramen of 

 Winslow or a finger could be inserted into it through an incision made just below 

 the stomach dividing the two anterior layers. This finger would come in contact 

 with another introduced from right to left through the foramen of Winslow. This 

 can rarely be done in the adult without breaking down adhesions, for the reason 

 that at about the age mentioned the anterior lamella of two layers fell back upon 

 the transverse colon and became adherent to the posterior lamella, obliterating 

 the cavity of the great omentum, which may now be called the omental plate. 

 Figure 606 shows the opportunity. This arrangement gives the stomach a direct 

 connection with the transverse colon and the two layers descending from the 

 greater curvature cannot be lifted from it. Our former great omentum may now 

 be called yastro-colic omentum ; some speak of the layers between stomach and 

 colon only as the gastro-colic part of the great omentum. 



This part connects on the left with the gastro-splenic omentum and on the 

 right with the hepatic flexure of the colon and descending colon, meeting there 

 the hepato-colic ligament, and is distinguished at those points as omentum colicum 

 (Haller). In later time, the great omentum is a four-cornered curtain which 

 hangs down from the great curvature of the stomach in front of the small intes- 

 tines fused with the transverse colon, ending usually in a free edge and descend- 

 ing a little lower on the left side as evidenced by its greater frequency in left 

 hernise. It may be tucked between the intestines or wholly pushed upward. It 

 may accumulate much fat. 



Its vessels vasa epiploica are chiefly derived from the art. gastro-epiploica 

 sinistra, only the smallest part from the dextra. It is poorly supplied with 

 lymphatics. Its nerves are from the coeliac plexus. 



The gastro-splenic omentum we have seen (Figs. 610 and 611) as a double 

 fold, dipping in between the fundus of the stomach and the gastric surface of the 

 spleen. It is where the greater sac has opportunity to touch the lesser sac 

 between these two organs. In this fold, made by two sacs, the splenic artery 

 sends its vasa brevia to the stomach. 



The lesser omentum (omentum minus) or g astro-hepatic omentum or lig. hepato- 

 gastricum passes nearly vertically between the transverse fissure of the liver and the 

 lesser curvature of the stomach, continuous to the right upon the first part of the 

 duodenum. This right free edge going to the duodenum, containing vessels, is 

 called the lig. hepato-duodenale. The lesser omentum and hepato-duodenal liga- 

 ment are made of two layers, one from the greater and one from the lesser sac. 

 An index finger passed into the foramen of Winslow, if approximated to the thumb 

 placed upon the anterior surface, includes the two layers, thin as they are. The 



