of the portal vein and then, for a short distance, became separated from the back of the portal vein by a thin piece of the neck of the pancreas. On emerging from behind the neck of the pancreas it lay between the portal vein and bile-duct, but on a plane posterior to both, and then passed behind the terminal part of the cystic duct, where it could be seen in the triangle of Chalot close to the right side of the bulge in the common hepatic artery.
DISCUSSIONThe presence of large right and left accessory hepatic arteries, together with a practically normal common hepatic artery, is a rare occurrence, and was not described among the cases studied by Flint and Michels.Among the zoo subjects examined by Michels, in 36 specimens the aberrant right arteries were the only right hepatic arteries present, replacing the normal right branch of the common hepatic artery, and arising from the arteries other than the coeliac artery, 24 of them from the superior mesenteric. I n 16 specimens there were accessory right hepatic arteries, 10 of which arose from the superior mesenteric. I n 30 specimens the aberrant left arteries replaced the normal left branch of the common hepatic, while in 24 cases there were accessory left arteries; in all these cases the left hepatic arteries arose almost exclusively from the left gastric. The occurrence of an accessory right hepatic artery, arising from the superior mesenteric, associated with a normal common hepatic artery, was found in 7 of the 200 specimens studied by Flint. A hepatic artery, either the common hepatic or an aberrant right artery, running behind the portal vein was observed in only 4 cases by Flint.In the present case, the common hepatic artery bulged to the right of the common hepatic duct, as was noted in cases described by Flint, who observed that the arterial bulge may be mistaken for a lymphgland. The accessory right hepatic artery noted in the present specimen would be in a vulnerable position during pancreatectomy, in opening the bileduct, or during dissection of the cystic duct in cholecystectomy .The accessory left hepatic artery in the present case, which would appear to be large enough to form the main arterial blood-supply to the left lobe of the liver, would be endangered when ligating the left gastric artery during, for example, a high partial or a total gastrectomy. The effect of interruption of the major part of the blood-supply to one lobe of the liver has not been ascertained in man. Normally, the extrahepatic anastomoses between the right and left hepatic arteries might compensate for such a loss, but in the present instance, accidental ligation of the left accessory hepatic might lead to permanent damage of the left lobe of the liver owing to the absence of anastomoses.
SUMMARYAn unusual combination of aberrant hepatic arteries in a dissecting-room specimen is described. The relation of the arterial conditions to certain surgical procedures is noted. I wish to thank Professor Francis Davies for his help and advice in the preparation of this report.
