Ductus pancreaticus accessorius

Most people have just one pancreatic duct.

However, some have an additional accessory pancreatic duct, also called the Duct of Santorini.

An accessory pancreatic duct can be functional or non-functional.

It may open separately into the second part of the duodenum, which is dorsal, and usually (in 70% of people) drains into the duodenum via the minor duodenal papilla.

In the other 30% of people, 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.