The duodenal bulb is the portion of the
duodenum
The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear, and the terms anterior intestine or proximal intestine m ...
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 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,
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. Approx ...
, 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 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
gastroduodenal artery and bleed.
Notes
External links
Diagram - look for figure #2, item #5* {{LoyolaMedEd, Radio/curriculum/GI/sandy44a.jpg
Digestive system