BRANCHES OF THE ABDOMINAL AORTA 615 



the right above the portal vein to the portal fissure, and gives off the following 

 branches: 



(1) Pancreatic branches. 



(2) Dorsal and ventral branches to the liver. The ventral branch is the larger; 

 it gives off the right gastric artery, which runs in the lesser omentum to supply the 

 origin of the duodenum and the pylorus, anastomosing with the dorsal branch of 

 the omaso-abomasal artery. 



(3) The cystic artery supplies the gall-bladder. 



(4) The gastro-duodenal artery divides into right gastro-epiploic and pan- 

 creatico-duodenal branches. The right gastro-epiploic artery anastomoses with 

 the left gastro-epii)loic. The pancreatico-duodenal arter}^ anastomoses with the 

 first intestinal branch of the anterior mesenteric artery. 



2. The right ruminal artery (A. ruminalis dextra) is the largest branch, and 

 usually arises l)y a short coniiuon trunk with the splenic. It runs downward and 

 backward on the right face of the dorsal sac of the rumen to the posterior transverse 

 fissure, in which it turns around to the left and anastomoses with branches of the 

 left ruminal artery. It gives off a pancreatic branch, dorsal and ventral coronary 

 arteries, brancii(>s to the great omentum, and ramifies on both surfaces of the rumen. 



3. The left ruminal artery (A. ruminalis sinistra) runs downward on the anterior 

 part of the right face of the rumen, enters the anterior furrow, in which it runs from 

 right to left, and continues backward in the left longitudinal groove, anastomosing 

 with branches of the right artery. It supplies chiefly the left face of the rumen, 

 but not its ])()sterior part. It usually gives off near its origin the reticular artery 

 (A. reticularis); this rather small vessel passes forward on the dorsal curvature of 

 the rumen and turns downward in the rumino-reticular groove, in the bottom of 

 which it runs around ventrally to the right side. It gives off a branch which passes 

 to the left of the cardia and along the lesser curvature of the reticulum to the neck 

 of the omasum. The reticular branches anastomose with the omaso-abomasal and 

 left ruminal arteries. 



4. The omaso-abomasal artery (A. gastrica sinistra) appears as the continua- 

 tion of the coeliac. It passes forward and downward to the greater curvature of 

 the omasum and divides after a course of four or five inches into two branches. 

 The dorsal branch curves sharply backward on the dorsal surface of the omasum, 

 continues along the lesser curvature of the abomasum, and anastomoses with the 

 hepatic artery. It supj^dies branches to the omasum and to the lesser curvature 

 and pyloric part of the abomasum. The ventral branch (A. gastro-epiploica 

 sinistra) runs forward and downward over the anterior extremity of the omasum, 

 passes backward in the great omentum close to the ventral curvature of the aboma- 

 sum, and anastomoses with the right gastro-epiploic. A considerable branch from it 

 curves around in front of the neck of the omasum to communicate wdth the reticular 

 artery. Another branch runs back across the left side of the omaso-abomasal 

 junction, and a third goes to the lesser (ventral) curvature of the omasum. 



5. The splenic artery usually arises by a common trunk with the right ruminal 

 artery. It passes forw^ard and to the left across the dorsal curvature of the rumen 

 and enters the hilus of the spleen. 



The anterior mesenteric artery arises from the aorta just behind the coeliac, 

 and has about the same caliber as the latter. It passes downward and a little to 

 the right, and crosses the colon as it emerges from the spiral to run backward. 

 After detaching twigs to the pancreas it gives off in succession the following 

 branches : 



1. A branch (A. colica media) passes to the colon as it emerges from the spiral 

 arrangement. This artery is comparable to the middle colic or artery of the 

 small colon of the horse; it runs backward along the terminal part of the colon, 

 which it supplies. 



