The =cœliac artery= is about four to five inches (ca. 10 to 12 cm.) in
length. It passes downward and curves forward between the rumen and
pancreas on the left and the right crus of the diaphragm and the
posterior vena cava on the right. It gives off five chief branches.
1. The =hepatic artery= arises from the convex side of the curve of the
cœliac artery as it crosses the posterior vena cava. It passes downward,
forward, and to 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
pancreatico-duodenal branches. The right gastro-epiploic artery
anastomoses with the left gastro-epiploic. The pancreatico-duodenal
artery 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 by a short common 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,
branches 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
posterior 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
continuation of the cœliac. 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
supplies branches to the omasum and to the lesser curvature and pyloric
part of the abomasum. The =ventral branch= (A. gastroepiploica 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 abomasum, and anastomoses with the right gastro-epiploic. A
considerable branch from it curves around in front of the neck of the
omasum to communicate with 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 forward 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
cœliac, 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.
[Illustration: