THE OMENTUM. 61 



nerves, while they are in the thorax, an important branch, 

 called the ramus splanchnicus, arises. These splanchnic 

 branches pass through the diaphragm, and are the chief con- 

 tributers to the ganglions and plexuses formed in the abdomen. 

 A plexus derived from this source surrounds the superior 

 mesenteric artery, and another the inferior mesenteric ; and 

 from these proceed the nerves of the intestines. 



The Omentum. 



Requires a separate description, although several circum- 

 stances connected with its structure have been already noticed. 

 It often varies in its position ; but when it is rendered firm by 

 a quantity of adipose matter, it is spread over the intestines 

 like an apron, extending from the lower edge, or great curva- 

 ture of the stomach, towards the bottom of the abdomen. 



As has been already said, it is an extension of the perito- 

 neum, in two lamina, from the concave surface of the liver to 

 the lesser curvature of the stomach ; and these lamina, after 

 surrounding the stomach, come in contact with each other near 

 its great curvature. From this portion of the stomach, from 

 the commencement of the duodenum, and also from the spleen, 

 the Omentum, composed of two lamina, descends over the 

 colon and the small intestines more or less low into the abdo- 

 men ; it is then folded backwards and upwards, and is continued 

 until it meets the great arch in the colon : here the lamina 

 again separate and enclose that portion of the intestine, on 

 the posterior side of which they again approach each other, 

 and form a membrane like the mesentery of two lamina, 

 which passes from the concave or posterior surface of the colon 

 to the back of the abdomen, where it is continued into the 

 membrane which lines that surface. This last portion is the 

 Mesocolon : the portion between the liver and stomach is called 

 the Omentum of Winslow, the lesser omentum or the omentum 

 hepatico-gastricum ; and the great portion between the stomach 

 and colon is called the Great Omentum, or the omentum gastro- 

 colicum. There is also a process of peritoneum continued from 

 that portion of the colon which is on the right side of the abdo- 



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