Most people have just one pancreatic duct. However, some have an additional accessory pancreatic duct also called the Duct of Santorini, which is dorsal and usually (in 70%) drains into to the duodenum via the minor duodenal papilla. In the other 30% it drains into the main pancreatic duct, which drains into the duodenum via the major duodenal papilla. The main pancreatic duct and the accessory duct both eventually - either directly or indirectly - connect to the second part ('D2', the vertical segment) of the duodenum.