Hepatopancreatic arterial ring: bilateral symmetric typology in human celiaco-mesenteric arterial system.

The celiac and mesenteric arterial system including the left gastric, splenic, common hepatic, and superior mesenteric arteries shows various types of origins, courses, ramifications and anastomoses. In order to explain the various expressions of this system, we have proposed a typological model, in which celiacomesenteric arteries develop as paired or bilaterally symmetrical primordial vessels originated from the anterior aspect of the aorta, and these vessels anastomose each other with longitudinal and horizontal pathways. Here, we report 3 unusual cases characterized by arterial rings, formed by the left gastric, left accessory hepatic, proper hepatic, anterior pancreaticoduodenal, and dorsal pancreatic arteries. The dorsal pancreatic and anterior pancreaticoduodenal arteries are located to the right and left of the embryonic pancreas developing in the dorsal mesentery, respectively. Such hepatopancreatic arterial rings simultaneously containing right and left elements can only be explained using our typological model, in which the concept of paired arteries or bilateral symmetry is introduced.