494 OMENTA MESENTERY. 



or posterior layer of the peritoneum ; below, the hepatic artery, 

 curving forwards from the coeliac axis ; and above, the lobus 

 Spigelii. These, therefore, are the boundaries of the foramen of 

 Winslow, which is nothing more than a constriction of the general 

 cavity of the peritoneum 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 omen- 

 tum. This is sometimes called the lesser cavity of the peritoneum, 

 and that external to the foramen the greater cavity ; in which case 

 the foramen is considered as the means of communication between 

 the two. There is a great objection to this division, as it might 

 lead the inexperienced to believe that there were really two cavi- 

 ties. 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 abdo- 

 men. 



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, 2dly. Facilitating the move- 

 ment of the intestines upon each other during their vermicular 

 action. 



The Transverse meso-colon (petfos, middle, being attached to the 

 middle of the cylinder of the intestine) is the medi-um of connexion 

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

 It also affords to the nutrient arteries a passage to reach the intes- 

 tine ; and encloses between its layers, at the posterior part, the trans- 

 verse portion of the duodenum. 



The Mesentery (pstfov gWsgov, being connected to the middle of the 

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

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

 oblique 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 passage to 

 the mesenteric arteries, veins, nerves, and lymphatics. 



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

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

 folds in the pelvis, as the recto-vesical fold, the false ligaments of the 

 bladder, and broad ligaments of the uterus. 



The Appendices epiploicce are small irregular pouches of perito- 

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

 tine. 



Three other duplicatures of peritoneum are situated in the sides 

 of the abdomen ; they are the gastro-phrenic ligamen , the gastro- 



