Anatomy of the duodenum
The Second (or “descending”) part of the duodenum is retroperitoneal and descends directly in front of the right renal vessels.
The major duodenal papilla is located in this part of the duodenum, and represents the site at which bile and pancreatic enzymes are secreted into the intestinal tract via contractions of the Hepatopancreatic ampulla (of Vater).
The location of the duodenal papilla also represents the junction between the embryological foregut and midgut.
