[Standardized sonographic measurement of the width of the extrahepatic bile ducts].

As there are no exact data available which part of the bile duct should be measured, the hepatoduodenal ligament was examined in 20 cadavers. The constant anatomic relationship between the right hepatic artery and the common hepatic duct is shown. A right hepatic artery properly originating from the hepatic artery passes to 85% dorsally and to 15% ventrally of the common hepatic duct, but remains ventrally to the portal vein. If the right hepatic artery is shown dorsal to the portal vein (20%), an accessory right hepatic artery should be suggested. To maintain uniformity of measurement, the size of the common hepatic duct should be recorded immediately caudal to the right hepatic artery.