THE COELOM, DIGESTIVE, AND RESPIRATORY SYSTEMS 19] 



the greater part of it first descends posteriorly, forming a bag, the greater omentum 

 This is a very large and extensive sheet in the cat, covering the intestine ventrallj 

 as noted above. In the rabbit it is a short membrane dependent from the greate: 

 curvature of the stomach. The greater omentum is to be thought of as formec 

 in the following way. Suppose one should grasp the mesogaster and pull it pos 

 teriorly, drawing it into a sac. Such a sac would have two walls, each double 

 i.e., composed of the two layers of the mesogaster; the sac would contain ; 

 cavity which is known as the lesser peritoneal sac and would open anteriorly (thi 

 opening will be seen later) (see Fig. 50, p 198.). By manipulating the omentun 

 determine that it consists of two separate walls. Having formed the greate 

 omentum the mesogaster returns to the stomach wall and passes onto the stomacl 

 along the greater curvature. The spleen is inclosed in the ventral wall of th< 

 great omentum just before the latter passes to the stomach. The portion of thi 

 great omentum between the spleen and the stomach is called the gastrospleni 

 (or gastrolienal) ligament. Posterior to the spleen, near the left kidney, a second 

 ary fusion, the gastrocolic ligament, has formed between the mesogaster and thi 

 mesentery of the intestine (see Fig. 50). 



The greater omentum owes its origin in part to the rotation of the stomach 

 The line of attachment of the omentum to the greater curvature is the origina 

 dorsal surface of the stomach, while the lesser curvature is the original ventra 

 surface. The mesogaster passes over the stomach, forming the visceral peri 

 toneum of the stomach, and inclosing the stomach between its walls, and a 

 the lesser curvature is continued by a strong ligament, the lesser omentum, whicl 

 passes to the liver. 



The liver may be studied next. It presents a convex anterior surface, fittinj 

 against the posterior surface of the diaphragm, and a concave posterior surface 

 fitting over the stomach and first part of the small intestine. The liver is divide* 

 into right and left lobes, each of which is subdivided into two lobes, a median and 

 lateral. The left lateral and right median lobes are larger than the others. I: 

 the cat the right lateral lobe is deeply cleft into two lobules. The large elongate* 

 gall bladder is imbedded in the right median lobe, on its dorsal surface in th 

 rabbit, in a cleft in this lobe in the cat. On raising the liver and looking betwee: 

 the liver and the stomach another small lobe, the caudate lobe, will be seen. It i 

 situated between the two layers of the lesser omentum. The lesser omentun 

 or gastro-hepato-duodenal ligament, is the ligament passing from the lesser curva 

 ture of the stomach to the posterior surface of the liver. It is divisible into tw 

 portions: the gastrohepatic ligament from the lesser curvature to the liver, an 

 the hepatoduodenal ligament from the liver to the first part of the small intestint 

 That portion of the gastrohepatic ligament which contains the caudate lobe c 

 the liver forms a sac which continues anteriorly the cavity of the greater omer 

 turn. In the hepatoduodenal ligament runs the bile duct which should be trace 

 from the gall bladder by gently dissecting in the ligament. Note the cystic du< 



