62 THE OMENTUM. 



men, and from the coecum, which extends to some distance ; it 

 is formed of two lamina, that compose a cavity of an angular 

 form. This has been called the Omentum Colicum. 



The great and small omentum, with a portion of the peri- 

 toneum on the back of the abdomen, form a sac, which encloses 

 a distinct cavity in the abdomen. The anterior part of this sac 

 is composed of two lamina, and between these lamina are the 

 stomach and the great arch of the colon. This cavity formed 

 by the two omenta, communicates with the general cavity of 

 the abdomen by a foramen of a semicircular form, called the 

 Foramen of Winslow, which is behind the great cord of the 

 vessels that go to the liver. 



The omentum is so delicate in structure, that when free from 

 fat, it is very liable to laceration, merely by adhering to the 

 fingers, if they are dry. Winslow therefore advised that some 

 unctuous substance should be rubbed on the hands, before they 

 were applied to it. 



The appearance of the great omentum is very different in 

 different persons. In the emaciated, it appears like a delicate 

 transparent membrane : in the corpulent, if is like a broad 

 mass of adeps, which sometimes is very thick. When it is thus 

 loaded with adeps, it is most commonly spread over the small 

 intestines : when it is free from fat, it is often compressed to- 

 gether, so as to form a small mass near the arch of the colon, 

 on the left side. 



The principal blood-vessels of the omentum are derived from 

 those of the stomach, and are called gastro-epiploic arteries 

 and veins. 



The use of this membrane in the animal economy has not 

 been ascertained with certainty. It seems probable that one of 

 its principal objects is to protect the small intestines, and lessen 

 the friction consequent upon their motion ; but it has been sup- 

 posed to answer several other important purposes.* 



* See Halleri Elernenta Physiologiac, vol. vi. page 381 ; Gavard, Traite de 

 Splanchnologie, page 350 ; and Dr. James Rush's Inquiry into the use of the 

 Omentum. 



