Superior Part of the Duodenum

pars superior duodeni

The superior part is the first part of the duodenum, about 5 cm long, running from the pylorus up and back to the right at the level of L1. Its first 2-3 cm, the duodenal bulb or cap, is mobile and covered by peritoneum, with the hepatoduodenal ligament attached above and the greater omentum below. The rest is retroperitoneal.

Anatomical Data

Structure & Supply

Location	From the pylorus at L1, passing to the right, upward and backward toward the neck of the gallbladder
Parts	Duodenal bulb (ampulla) Attachment of hepatoduodenal ligament Attachment of greater omentum
Nerve Supply	Vagus nerve; Coeliac plexus
Blood Supply	Supraduodenal artery; Gastroduodenal artery and its retroduodenal branches; Right gastric artery
Venous drainage	Prepyloric and pancreaticoduodenal veins Hepatic portal vein
Lymphatic drainage	Pyloric nodes Hepatic nodes Coeliac nodes

Biomechanics

Function & Actions

Receives acid chyme from the stomach and begins neutralising it with alkaline mucus from duodenal glands.

Clinical Relevance

Clinical Notes

Most duodenal ulcers occur here. An ulcer on the front wall may perforate into the peritoneal cavity, giving free air under the diaphragm and peritonitis, while an ulcer on the back wall may erode the gastroduodenal artery, which lies just behind it, and cause major bleeding. The common bile duct and portal vein also run directly behind this part.

Pathology

Common Injuries & Conditions

Perforated Duodenal Ulcer

Full-thickness perforation of an anterior wall ulcer causing sudden severe abdominal pain, peritonitis and free intraperitoneal gas.

Bleeding Posterior Duodenal Ulcer

Ulcer of the back wall eroding the gastroduodenal artery, causing haematemesis or melaena and often needing endoscopic or radiological control.

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