228 ANATOMY OF THE ABDOMEN. 



THE OMENTUM, 



The omentum consists of folds of the peritoneum. One 

 cavity is spoken of as the large peritoneal sac {Fig 22 . LP) ; 

 the other as the lesser peritoneal sac {Fig 22 . SP) . The 

 larger peritoneum floats over part of the anterior surface 

 of the liver {Fig 22 . L) ; thence upon the posterior surface 

 of the diaphragm {Fig 22 . D). From this over the abdo- 

 minal muscles. Afterward upon the anterior portion of 

 the bladder {Fig 22 . B). Hence to the spine, whence it 

 descends to form the mesocolon {Fig 22. MC), and to 

 encircle part of the rectum {Fig 22 . R). Having done 

 this it proceeds forward, constitutes the mesentery, and 

 supports the small intestines {Fig 22 . I). After which it 

 covers part of the colon {Fig 22 . C) ; and then floating 

 loose in the abdomen constitutes one layer of the omentum 

 {Fig 22 . 0) which joins the stomach, over a portion of 

 which this peritoneal layer is reflected {Fig 22 . SS) ; and 

 then goes to the posterior part of the liver, from which 

 place it winds round to unite with the peritoneum upon 

 the anterior portion of the liver, from which point we 

 first set out. The lesser peritoneal sac is reflected 

 from the top of the liver {Fig 22 . L) to the crura of the 

 diaphragm {Fig 22 . D) over the pancreas ; it then descends, 

 constituting one side of the mesocolon (Fig 22 . MC) , and 

 covering part of the intestine, floats loose, forming the 

 inner layer of omentum {Fig 22 . 0) ; whence it joins the 

 stomach, a part of which, together wdth the spleen, it over- 

 lays {Fig 22 . SS) ; to be thence reflected to the top of the 

 liver, the point at which this description commenced. 

 "Within these duplicatures, adipose nodules are dispersed. 

 In the ox and in the sheep also, the folds inclose the four 

 stomachs and part of the duodenum : but in the horse their 

 extent is small ; besides it has attachments to the great cur- 

 vature of the stomach, which it does little more than cover, 

 as well as to a portion of the colon, to which it is also ap- 

 pended. The horse, therefore, is not subject to epiplocele. 

 The uses of the omentum are to facilitate the peristaltic 

 action, or to allow the abdominal viscera to glide over each 

 other without friction : it likewise serves as a store-house 

 for fat, against a period of starvation, during which the 

 adipose matter would be absorbed. 



