2OO 



THE ENTODERMAL CANAL AND ITS DERIVATIVES 



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

 inferior recess of the omental bursa thus may be limited 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. 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 

 have seen (p. 188) that the cranial portion of the ventral mesentery forms the 

 mesocardium of the heart. In the ventral mesentery caudal to the septum trans- 



A B c 



FIG. 195. 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, duode- 

 num; E, pancreas; F, greater omentum. 



versum develops the liver. From the first, it is enveloped in folds of the splanch- 

 nic mesoderm which give rise to its capsule and ligaments as the liver increases 

 in size (Fig. 183 B). Wherever the liver is unattached, the mesodermal layers 

 of the ventral mesentery form its capsule (of Glisson), a fibrous layer covered 

 by mesothelium continuous with that of the peritoneum (Fig. 183 B). Along 

 its mid-dorsal and mid- ventral line the h'ver remains attached to the ventral 

 mesentery. The dorsal attachment between the liver, stomach and duodenum 

 is the lesser omentum. This in the adult is differentiated into the duodeno-hepatic 

 and gastro-hepatic ligaments. The attachment of the liver to the ventral body 

 wall extends caudally to the umbilicus and forms the falciform ligament. 



In its early development the liver abuts upon the septum transversum, and 

 in 4 to 5 mm. embryos is attached to it along its cephalic and ventral surfaces. 



