The duodenal bulb (also ampulla of duodenum, duodenal ampulla, or duodenal cap) is the initial, dilated portion of (the superior part of) the

duodenum The duodenum is the first section of the small intestine in most vertebrates, including mammals, reptiles, and birds. In mammals, it may be the principal site for iron absorption. The duodenum precedes the jejunum and ileum and is the shortest p ...

just distal to the

stomach The stomach is a muscular, hollow organ in the upper gastrointestinal tract of Human, humans and many other animals, including several invertebrates. The Ancient Greek name for the stomach is ''gaster'' which is used as ''gastric'' in medical t ...

; it begins at the

pylorus The pylorus ( or ) connects the stomach to the duodenum. The pylorus is considered as having two parts, the ''pyloric antrum'' (opening to the body of the stomach) and the ''pyloric canal'' (opening to the duodenum). The ''pyloric canal'' ends a ...

and ends at the neck of the

gallbladder In vertebrates, the gallbladder, also known as the cholecyst, is a small hollow Organ (anatomy), organ where bile is stored and concentrated before it is released into the small intestine. In humans, the pear-shaped gallbladder lies beneath t ...

. It is normally about 5 centimeters long.

Structure

Relations

It is located posterior to the liver and the gallbladder and superior to the pancreatic head. The

gastroduodenal artery In anatomy, the gastroduodenal artery is a small blood vessel in the abdomen. It supplies blood directly to the pylorus (distal part of the stomach) and proximal part of the duodenum. It also indirectly supplies the pancreatic head (via the anterio ...

portal vein The portal vein or hepatic portal vein (HPV) is a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver. This blood contains nutrients and toxins extracted from digested contents. Approxima ...

, and

common bile duct The common bile duct (also bile duct) is a part of the biliary tract. It is formed by the union of the common hepatic duct and cystic duct. It ends by uniting with the pancreatic duct to form the ampulla of Vater (hepatopancreatic ampulla). ...

are situated posterior to the duodenal bulb. The distal part of the bulb is located retroperitoneally. It is located immediately distal to the

pyloric sphincter The pylorus ( or ) connects the stomach to the duodenum. The pylorus is considered as having two parts, the ''pyloric antrum'' (opening to the body of the stomach) and the ''pyloric canal'' (opening to the duodenum). The ''pyloric canal'' ends a ...

Clinical significance

The duodenal bulb is the site of duodenal ulcer occurrence. Duodenal ulcers are more common than gastric ulcers and - unlike gastric ulcers - are caused by increased gastric acid secretion. Duodenal ulcers are commonly located anteriorly, and rarely posteriorly. Anterior ulcers can be complicated by perforation, while the posterior ones bleed. The reason for that is explained by their location. The peritoneal or abdominal cavity is located anterior to the duodenum. Therefore, if the ulcer grows deep enough, it will perforate, whereas if a posterior ulcer grows deep enough, it will penetrate the

and bleed.

Notes

External links

Diagram - look for figure #2, item #5
* {{LoyolaMedEd, Radio/curriculum/GI/sandy44a.jpg

Digestive system