BODY CAVITIES, DIAPHRAGM AND MESENTERIES 



191 



When the stomach changes its position and form so that its mid-ventral 

 line becomes the lesser curvature and lies to the right, the position of the lesser 

 omentum is also shifted. From its primitive location in a median sagittal plane 

 with its free edge directed caudally, it is rotated through 90° until it lies in a cor- 

 onal plane with its free margin facing to the right (Fig. 194). The epiploic fora- 

 men now forms a slit-Uke opening leading from the peritoneal cavity into the ves- 

 tibule of the omental bursa. The foramen is bounded ventrally by the edge of 

 the lesser omentum, dorsally by the inferior vena cava, cranially by the caudate 

 process of the hver, and caudally by the wall of the duodenum. 



During fetal life the greater omentum grows rapidly to the left and caudad 

 in the form of a sac, flattened dorso-ventrally. It overlies the intestines ven- 





Fig. 202. — Diagrams showing the development of the mesenteries (Hertwig). A illustrates the 

 beginning of the great omentum and its independence of the transverse mesocolon; in B the two come 

 into contact; in C they have fused; A, stomach; B, transverse colon; C, small intestine; D, duodenum; 

 E, pancreas; F, greater omentum; G, greater sac; H, omental bursa. 



trally and contains the inferior recess of the omental bursa (Fig. 202) . The dor- 

 sal wall of the sac during the fourth month usually fuses with the transverse colon 

 where it overlies the latter (Fig. 202 B). Caudal to this attachment the walls 

 of the greater omentum may be fused and its cavity is then obhterated. The 

 inferior recess of the omental bursa thus may be Hmited in the adult chiefly to a 

 space between the stomach and the dorsal fold of the greater omentum, which 

 latter is largely fused to the peritoneum of the dorsal body wall. The spleen 

 develops in the cranial portion of the greater omentum and that portion of the 

 omentum which extends between the stomach and spleen is known as the gastro- 

 lienic ligament (Fig. 200). The dorsal wall of the omentum between the spleen 

 and kidney is the lieno-renal ligament. 



Further Differentiation of the Mesenteries. — Ligaments of the Liver. — We 



