The common bile duct , sometimes abbreviated CBD, is a tube-like anatomic structure in the gastrointestinal tract of organisms that have a gall bladder. It is formed by the union of the common hepatic duct and the cystic duct (from the gall bladder). It is later joined by the pancreatic duct to form the ampulla of Vater. There, the two ducts are surrounded by the muscular sphincter of Oddi.