The coeliac artery, [a. coeliaca, French : tronc cœliaque] , a short and very thick vessel, arises from the aorta close to the margin of the diaphragm. In the erect position of the body its direction is nearly horizontal forwards, and it is not more than half an inch long.

It is behind the small omentum, and lies close to the left side of the lobulus Spigelii of the liver, and above the pancreas, the two semilunar ganglia being in apposition with it, one on each side. After this very short course, the artery divides into three branches, viz., the coronary artery of the stomach, the hepatic, and the splenic. These three branches separate at the same time from the end of the artery like radii from an axis, whence, says Winslow, this trunk has been called axis arteriae coeliacae. Besides these which supply the the coeliac usually gives off one branch to the walls of the abdomen, viz., one of the phrenic arteries.

The coeliac axis is from time to time partly covered at its origin by the diaphragm. It may be longer than usual, in which case its branches are not given off together , or it may be wanting altogether the coronary, hepatic, and splenic arteries, arising separately from the aorta.the coronary, hepatic, and splenic arteries, arising separately from the aorta. In some cases the coeliac artery gives off only two branches at its division, (the coronary and the splenic,) the hepatic being supplied from another source. Rarely, it gives more than three branches to the viscera, the additional vessel being a second coronary, or a separate gastro- duodenal artery. Both phsenic arteries are sometimes derived from this trunk.

Cases have been met with in which a connection existed between the coeliac axis and the superior mesenteric artery close to their origin.