Common bile duct stones are mostly located in the middle and lower sections of the common bile duct. However, as the number of stones increases, the common bile duct expands, and the stones accumulate or move up and down, the common hepatic duct is often affected. The meaning of common bile duct stones should actually include the entire extrahepatic bile duct stones including the common hepatic duct. The sources of common bile duct stones are divided into primary and secondary. Primary common bile duct stones are a component of primary bile duct stones. They can be formed in the common bile duct, or stones originating from the intrahepatic bile duct descend into the common bile duct. Secondary common bile duct stones refer to stones originating from the gallbladder that descend into the common bile duct through the cystic duct.