Major Duodenal Papilla
Major duodenal papilla is the mucosal opening through which bile and pancreatic secretions enter the duodenum.
The major duodenal papilla is a small but critical anatomical structure located in the second part of the duodenum. It marks the opening where the common bile duct and the main pancreatic duct empty their contents into the gastrointestinal tract. This papilla is the site of the hepatopancreatic ampulla (ampulla of Vater) and is regulated by the sphincter of Oddi. Despite its small size, the major duodenal papilla plays a central role in digestive physiology and is a common site of disease processes, including choledocholithiasis, pancreatitis, and ampullary tumors. It also serves as a key target in endoscopic procedures such as ERCP (Endoscopic Retrograde Cholangiopancreatography).
Structure
The major duodenal papilla is a conical or dome-shaped elevation on the medial wall of the second portion of the duodenum. It is formed where the hepatopancreatic ampulla pierces the mucosa. Structurally, it contains the junction of the biliary and pancreatic systems and is surrounded by smooth muscle fibers constituting the sphincter of Oddi.
Anatomical Components
Component | Description |
---|---|
Common bile duct | Delivers bile from the liver and gallbladder |
Main pancreatic duct (duct of Wirsung) | Delivers pancreatic enzymes |
Hepatopancreatic ampulla (ampulla of Vater) | Fused terminal segment of both ducts just before entry into the duodenum |
Sphincter of Oddi | Circular smooth muscle regulating the flow of bile and pancreatic juice |
The ampulla may vary anatomically — in about 10–15% of people, the common bile duct and pancreatic duct enter the duodenum separately, without forming a true ampulla.
Dimensions
- Length: 1–1.5 cm (ampulla)
- Diameter of papilla: 2–5 mm protrusion into the duodenal lumen
Location
The major duodenal papilla is located in the posteromedial wall of the descending (second) part of the duodenum. It lies roughly halfway between the pylorus and the duodenojejunal flexure.
Topographic Details
- Region: Second (descending) part of the duodenum
- Level: Approximately at L2 vertebral level
- Medial to: The lumen of the duodenum
- Posterior to: The pancreas head and common bile duct
- Landmark: Located about 7–10 cm distal to the pylorus
It serves as a useful endoscopic landmark and is the primary access point for diagnostic and therapeutic procedures targeting the biliary and pancreatic ducts.
Function
The major duodenal papilla is the anatomical gateway for bile and pancreatic juice to enter the duodenum. These secretions are essential for digestion and pH regulation of chyme entering from the stomach.
Bile and Enzyme Delivery
- Bile: Emulsifies fats and aids in absorption of fat-soluble vitamins
- Pancreatic enzymes: Break down proteins, carbohydrates, and fats
Sphincter of Oddi Regulation
The flow through the papilla is controlled by the sphincter of Oddi, which has three distinct parts:
- Sphincter choledochus: Surrounds the terminal bile duct
- Sphincter pancreaticus: Surrounds the terminal pancreatic duct
- Sphincter ampullae: Surrounds the common ampullary chamber (if present)
These sphincters open in response to hormonal signals (like cholecystokinin) and vagal stimulation during digestion. During fasting, the sphincter remains closed, diverting bile into the gallbladder for storage.
Clinical Relevance
The major duodenal papilla is implicated in various pathological conditions and is a central focus in gastrointestinal and hepatobiliary interventions.
1. Choledocholithiasis
- Definition: Presence of gallstones in the common bile duct
- Impact: Stones may lodge at the ampulla, causing biliary obstruction
- Symptoms: Jaundice, biliary colic, cholangitis
2. Acute Pancreatitis
Obstruction or dysfunction at the level of the major papilla can lead to backflow of pancreatic secretions, triggering pancreatitis. This is especially true when gallstones obstruct the common channel shared by bile and pancreatic ducts.
3. Ampullary Tumors
- Ampullary adenoma or carcinoma: Tumors can arise directly from the epithelial lining of the papilla
- Presentation: Often causes painless jaundice due to bile duct compression
- Diagnosis: Endoscopic biopsy via ERCP or endoscopic ultrasound (EUS)
- Treatment: May require local resection or pancreaticoduodenectomy (Whipple procedure)
4. ERCP and Papillotomy
The major papilla is the access point for endoscopic retrograde cholangiopancreatography (ERCP), which is used to:
- Inject contrast into bile or pancreatic ducts
- Extract stones from the bile duct
- Place stents across narrowed ducts
- Perform a sphincterotomy (cutting the sphincter) to improve drainage
5. Sphincter of Oddi Dysfunction (SOD)
This functional disorder involves inappropriate or uncoordinated contraction of the sphincter, leading to:
- Biliary-type pain without stones
- Transient elevation in liver or pancreatic enzymes
- Diagnosed via manometry (pressure studies during ERCP)
It is treated with endoscopic sphincterotomy if conservative management fails.
Last updated on May 7, 2025