Major duodenal papilla

Structure

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 junction between the foregut and midgut occurs directly below the major duodenal papilla. 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.