BRANCHES OF THE ABDOMINAL AORTA 



617 



2. The ileo-caeco-colic artery ramifies on the right face of the spiral part of the 

 colon. It gives off the ileo-caecal artery, which divides into ileal and caecal arteries. 



3. An artery (Ramus collateralis) runs in the mesentery in a curve along the 

 ventral border of the coils of the colon. (This vessel is absent in the sheep.) 



4. An artery which constitutes the direct continuation of the anterior mesen- 

 teric pursues a course in the mesentery corresponding to the series of mesenteric 

 lymph glands. 



The two preceding vessels are essentiallj' the arteries of the small intestine, 



Fig. 474. — Pi..\x of Br.\nches of A.nterior Mesenteric Artery of Ox. 

 1, Anterior mesenteric artery; 2, middle colic artery; S, ileo-cseco-colic artery; 4, ramus collateralis; 5, 

 continuation of anterior mesenteric artery, giving off branches to small intestine; 6, csecal artery; 7, colic branch 

 of posterior mesenteric artery; .4, termination of duodenum. 



which they supply with the exception of its initial and terminal parts. The first 

 gives off no considerable branches in its course along the ventral border of the coils 

 of the colon, but on curving upward along the latter it anastomoses with the second 

 artery and detaches numerous branches to the small intestine which form series of 

 superposed anastomotic arches. It supphes, roughly speaking, about one-third of 

 the small intestine and terminates by joining the ileal artery. The second artery 

 gives off numerous branches which also form arches and supply about the first 

 two-thirds of the small intestine, exclusive of the small part supplied by branches 

 of the coehac artery. Both arteries give branches to the lymph glands.' 



1 It is difficult to make the arrangement of these vessels clear in a brief textual description, 

 but a reference to the schematic figure will explain the main facts. 



