The duodenal bulb is the portion of the duodenum closest to the

stomach The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach i ...

. It normally has a length of about 5 centimeters. The duodenal bulb begins at the

pylorus The pylorus ( or ), or pyloric part, 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 ''pylori ...

and ends at the neck of the

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

. It is located posterior to the liver and the gallbladder and superior to the

pancreatic head The pancreas is an organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e. it has both an endocr ...

. 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, and

common bile duct The common bile duct, sometimes abbreviated as CBD, is a duct in the gastrointestinal tract of organisms that have a gallbladder. It is formed by the confluence of the common hepatic duct and cystic duct and terminates by uniting with pancrea ...

lie just behind it. The distal part of the bulb is located retroperitoneally. It is located immediately distal to the

pyloric sphincter The pylorus ( or ), or pyloric part, 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 ''pylori ...

. The duodenal bulb is the place where duodenal ulcers occur. 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