558 OMENTUM. MESO-COLON. MESENTERY. 



at this point, arising out of the necessity for the hepatic and gastric 

 arteries to pass forwards from the coeliac axis to reach their respective 

 viscera. 



If air be blown through the foramen of Winslow, it will descend 

 behind the lesser omentum and stomach to the space between the 

 descending and ascending pair of layers, forming the great omentum. 

 This is sometimes called the lesser cavity of the peritoneum, and that 

 external to the foramen the greater cavity ; in which case the fora- 

 men is considered as the means of communication between the two. 

 There is a great objection to this division, as it might lead the inex- 

 perienced to believe that there were really two cavities. There is but 

 one only, the foramen of Winslow being merely a constriction of that 

 one, to facilitate the communication between the nutrient arteries and 

 the viscera of the upper part of the abdomen. 



The Great omentum consists of four layers of peritoneum, the two 

 which descend from the stomach, and the same two, returning upon 

 themselves to the transverse colon. A quantity of adipose substance 

 is deposited around the vessels which ramify through its structure. 

 It would appear to perform a double function in the economy. 1st. 

 Protecting the intestines from cold ; and, 2ndly. Facilitating the 

 movement of the intestines upon each other during their vermicular 

 action. 



The Transverse meso-colon (pie-a;, middle, being attached to the 

 middle of the cylinder of the intestine) is the medium of connection 

 between the transverse colon and the posterior wall of the abdomen. 

 It also affords to the nutrient arteries a passage to reach the intestine, 

 and encloses between its layers, at the posterior part, the transverse 

 portion of the duodenum. 



The Mesentery (piffov sW^av, being connected to the middle of the 

 cylinder of the small intestine) is the medium of connection between 

 the small intestines and the posterior wall of the abdomen. It is ob- 

 lique in its direction, being attached to the posterior wall, from the 

 left side of the second lumbar vertebra to the right iliac fossa. It 

 retains the small intestines in their places, and gives passages to the 

 mesenteric arteries, veins, nerves, and lymphatics. 



The Meso-rectum, in like manner, retains the rectum in connection 

 with the front of the sacrum. Besides this, there are some minor 

 folds in the pelvis, as the rectovesical fold, the false liyaments of the 

 bladder, and the broad ligaments of the uterus. 



The Appendices epiploicae are small irregular pouches of the perito- 

 neum,filled with fat, and situated like fringes upon the large intestine. 



Three other duplicatures of the peritoneum are situated in the sides of 

 the abdomen ; they are the gastro-phrenic ligament, the gastro-splenic 

 omentum, the ascending and descending meso-colon. The gastro- 

 phrenic ligament is a small duplicature of the peritoneum, which de- 

 scends from the diaphragm to the extremity of the oesophagus, and 

 lesser curve of the stomach. The gastro-splenic omentum is the dupli- 

 cature which connects the spleen to the stomach. The ascending 



