What is the duodenum and what is its function?

The duodenum is the first part of the small intestine. It receives chyme from the stomach and mixes it with bile and pancreatic secretions to aid digestion.

How is the duodenum divided into parts?

It has four parts: First (Superior) Part: 5 cm long, site of duodenal ulcers. Second (Descending) Part: 7.5 cm, receives bile and pancreatic ducts. Third (Horizontal) Part: 10 cm, crosses anterior to aorta and IVC. Fourth (Ascending) Part: 2.5 cm, ascends to the duodenojejunal flexure.

What are the key internal features of the duodenum?

Key features include: Major duodenal papilla: Opening for bile and pancreatic ducts. Minor duodenal papilla: Opening for the accessory pancreatic duct. Duodenal cap: Smooth mucosa in the first part. Plica circularis: Circular folds that aid digestion.

What is the blood supply to the duodenum?

Arterial supply comes from two main sources: Upper half: Superior pancreaticoduodenal artery (from gastroduodenal/coeliac trunk). Lower half: Inferior pancreaticoduodenal artery (from superior mesenteric artery). Venous drainage goes into the portal system.

Why is the duodenum prone to ulcers?

Duodenal ulcers are common in the first part due to exposure to stomach acid and its end arteries, which can limit blood flow and healing.

What is the ligament of Treitz and why is it important?

The ligament of Treitz is a fibromuscular band that suspends the duodenojejunal flexure from the diaphragm. It acts as a surgical landmark and helps fix the duodenum in place.

How is the duodenum related to clinical procedures like ERCP?

During ERCP, the major duodenal papilla is catheterized to access the bile and pancreatic ducts for diagnosis or treatment.

What are duodenal recesses and why do they matter?

Duodenal recesses are peritoneal pouches near the duodenum, such as the superior and inferior duodenal recesses. They can be sites for retroperitoneal hernias if abnormal.

Duodenum Anatomy – 4 Parts, Relations & Major Papilla

❓ Frequently Asked Questions