DUCTS, VESSELS, AND NERVES, ETC. 179 



folds. Besides supplying the small intestine, the mesenteric 

 artery sends a separate division, called the ileo-colic, to the 

 caecum and termination of the ileum; another single divi- 

 sion supplies the ascending colon, and is called the colica 

 dextra; a third branch supplies the transverse colon, being 

 called the colica media; these three trunks anastomose 

 together by their terminal branches, and the last named 

 inosculates with the colica sinistra, a branch of the inferior 

 mesenteric, which supplies the descending colon and sig- 

 moid flexure, "and so completes," says John Bell, u the 

 great mesenteric arch, one of the most celebrated inoscula- 

 tions in the whole body, that of the circle of Willis hardly 



:cepted." 



* These several branches of the mesenteric artery are 

 accompanied by the nerves which constitute the, superior 

 mesenteric plexus ; they can be found, together with several 

 ganglionic masses, at the commencement of the artery, 

 which they surround, and may be traced back to the solar 

 plexus ; they supply the pancreas and intestinal canal. 



In the intervals of the branches of the mesenteric vessels 

 numerous lymphatic glands are lodged ; these are called 

 the mesenteric glands ; the chyliferous vessels of the small 

 intestine pass through these to reach the thoracic duct ; 

 these glands are often enlarged by disease. 



The INFERIOR MESENTERIC ARTERY arises about two 

 inches below the superior, also from the front of the 

 aorta; it inclines to the left, and by a series of arches 

 supplies the descending colon under the name of the colica 

 ftini.xtra, forming large and free anastomoses with the 

 colica media of the superior mesenteric ; a second branch 

 passes to the sigmoid flexure, and is called the sigmoid 

 nrfrry, and its terminal branch goes to the mesentery of 

 the rectum, under the name of the superior hemorrhoidal 

 (irfrry ; these three branches anastomose freely with each 

 other. 



: The front of the aorta, between the mesenteric arteries, 

 is covered by the aortic plexus of nerves ; this connects 

 with the solar plexus, and also unites with the lumbar 

 ganglia, situated upon the sides of the vertebrae ; from it 

 passes off the inferior mesenteric plexus, which, accom- 

 panying the artery of that name, supplies the parts to 

 which that vessel is distributed. 



The intestines should now be removed. To do this the rectum is 

 to be tied and divided ; the large intestine should then be dissected 



