the human embryo starts life with two ducts in the pancreas; the ventral duct and the dorsal duct. in more than 90% of the embryos the dorsal and the ventral ducts will fuse to form one main pancreatic duct. the main pancreatic duct will join the common bile duct (the duct that drains bile from the gallbladder and the liver) to form a common bile and pancreatic duct which drains into the duodenum through the major papilla. in approximately 10% of embryos the dorsal and the ventral ducts fail to fuse. failure of the ventral and the dorsal pancreatic ducts to fuse is called pancreas divisum (because the pancreas is drained by two ducts). in pancreas divisum the ventral duct drains into the major papilla while the dorsal duct drains into a separate minor papilla.
what causes pancreas divisum?