The major duodenal papilla is situated in the second part of the
duodenum, 7–10 cm from the
pylorus, at the level of the second or third
lumbar vertebrae. It is surrounded by the
sphincter of Oddi, a circular muscle, and receives a mixture of pancreatic enzymes and
bile from the
Ampulla of Vater, which drains both the
pancreatic duct and
biliary system. The major duodenal papilla projects less than a centimetre into the
lumen of the duodenum. It appears rounded and is often covered by a fold on the uppermost side of the papilla; that is, the side which receives contents from the stomach. The major duodenal papilla is seen from the duodenum as lying within a
mucosal fold. The
minor duodenal papilla is situated 2 cm proximal.
Variation The major duodenal papilla is occasionally found in the junction between the descending and horizontal parts of the duodenum, or in the horizontal part of the duodenum; a case study of 1000 people demonstrated this in 12 and 8% respectively. in the third part of the duodenum, the level of the vertebrae may be L2-3, and in about 10% of people, it may not receive
bile. Additionally, in a small number of people, the primary papilla for draining the pancreas may in fact be the
accessory pancreatic duct. == Function ==