The common hepatic duct is the duct formed by the convergence of the right hepatic duct (which drains bile from the right functional lobe of the liver) and the left hepatic duct (which drains bile from the left functional lobe of the liver). The common hepatic duct then joins the cystic duct coming from the gallbladder to form the common bile duct. The duct is usually 6–8 cm length and 6mm in diameter in adults.