Major duodenal papilla

Where is the ampulla of Vater located?

The major duodenal papilla is located in the descending part of the duodenum, on its posteromedial wall. Topographically, this corresponds to the middle of the descending part or the border of its middle and lower thirds.

The mucous membrane in this region forms permanent circular folds (plicae circulares), occupying about ½–⅔ of the intestinal circumference. However, on the medial wall (in the lower, less frequently in the upper half of the descending part), the longitudinal fold of the duodenum (plica longitudinalis duodeni) is formed. Its length is about 11 mm, and the major papilla is located precisely at its distal end.

3–4 cm proximal to it, the minor duodenal papilla (papilla duodeni minor) may be present, where the accessory pancreatic duct opens (occurs in more than 30% of cases).

Morphology and structure

Visually, the structure appears as an elevation ranging from 0.2 to 2 cm in height. The diameter of the orifice at the apex varies from 2.0 to 4.5 mm.

Often, the papilla is covered superiorly by a proximal transverse fold of the mucous membrane, which is 1–2 cm in length.

In the region of the orifice lies the sphincter of the hepatopancreatic ampulla (m. sphincter ampullae hepatopancreaticae). It functionally combines the sphincter of the common bile duct and the sphincter of the pancreatic duct.

Which ducts open into the major papilla?

The common bile duct and the pancreatic duct open at the apex of the papilla:

• Common bile duct (ductus choledochus) — its interstitial (intramural) part is about 1.6 cm long and pierces the posterior wall of the duodenum in an oblique direction.
• Pancreatic duct (ductus pancreaticus) — runs through the entire gland from the tail to the head and approaches the papilla. Before its opening, its circular muscle layer thickens to form its own sphincter (m. sphincter ductus pancreatici).

Two variants of the opening of these ducts are distinguished:

1. Formation of a common ampulla (80% of cases): in the region of the right margin of the head of the pancreas, the ducts merge. They form the hepatopancreatic ampulla (ampulla hepatopancreatica, or biliopancreatica), which opens via a single orifice.
2. Separate orifices (20% of cases): the ducts do not merge and open at the apex of the papilla via two separate orifices, one located above the other.

Clinical significance

• Gastrointestinal surgery: When managing a bleeding ulcer of the posterior duodenal wall, the surgeon must consider the topography of this region to eliminate the risk of injuring the major duodenal papilla, the common bile duct, and the underlying pancreatic tissues.
• Oncological practice: According to the NCCN Guidelines in Oncology (2010), a separate TNM staging classification for neuroendocrine tumors has been approved for the small intestine, including the duodenum and the ampulla of Vater.

Class and exam questions

What else to study on this topic

• Duodenum
• Common bile duct (ductus choledochus)
• Pancreas
• Hepatopancreatic ampulla (ampulla hepatopancreatica)

Other topics in the "Anatomical Structures" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.