Duodenum (English)

The anterior wall of the superior and descending parts of the duodenum is removed to reveal its internal structure. Circular folds (of Kerckring) define the mucosa from the descending part onwards. Two small openings are seen amongst them in the descending part of the duodenum. The major duodenal papilla allows pancreatic enzymes and bile to enter the duodenum from the union of the pancreatic duct and bile duct, known as the hepatopancreatic ampulla. The minor duodenal papilla is an opening for pancreatic enzymes from the accessory pancreatic duct. The different layers of the duodenum are exposed on its horizontal part. The head of the pancreas sits within the curve of the duodenum. The abdominal aorta, hepatic portal vein (pictured), inferior vena cava, pancreaticoduodenal arteries, bile duct, right kidney, ureter and psoas major, gonadal vessels and vertebra L3 (not pictured) are located posterior to the duodenum. The superior mesenteric artery and vein (pictured), right lobe of the liver and the gallbladder (not pictured) extend over the anterior surface of the duodenum.