[2] It is located posterior to the liver and the gallbladder and superior to the pancreatic head.

[citation needed] The gastroduodenal artery,[3] portal vein, and common bile duct are situated posterior to the duodenal bulb.

Duodenal ulcers are commonly located anteriorly, and rarely posteriorly.

Anterior ulcers can be complicated by perforation, while the posterior ones bleed.

The peritoneal or abdominal cavity is located anterior to the duodenum.