Organ
Superior (first) part of the duodenum
The proximal duodenum beside the gastric outlet
High-yield
The duodenal bulb is a frequent site of peptic ulceration. The gastroduodenal artery behind it explains one source of severe ulcer bleeding.
Overview
The first duodenal segment leaves the pylorus and runs rightward before turning downward. Its proximal approximately 2 cm remains relatively mobile and is covered by peritoneum on both sides; the more distal portion is fixed to the posterior wall.
Reference facts
- Location
- Begins near L1 in a supine adult and passes rightward, posteriorly and slightly superiorly from the pylorus.
- Parts
- A mobile proximal bulb or cap followed by a more fixed distal first portion; only the initial short segment is freely peritoneal on both surfaces.
- Blood supply
- Variable supraduodenal and adjacent gastric branches, together with superior pancreaticoduodenal branches.
- Innervation
- Vagal and sympathetic fibers through the celiac region modulate enteric activity; visceral pain is commonly epigastric.
- Venous/Lymphatic drainage
- Veins reach the portal system through prepyloric and pancreaticoduodenal routes; lymph passes toward pyloric and pancreaticoduodenal nodes.
- Relations
- Liver and gallbladder are anterior; gastroduodenal artery, bile duct and portal vein lie posteriorly. This segment bounds the epiploic foramen inferiorly.
- Function
- Receives acidic chyme and participates in mixing it with alkaline secretions that protect the intestinal mucosa.
Clinical correlation
A posterior bulb ulcer can erode the gastroduodenal artery, while an anterior ulcer may perforate into the peritoneal cavity. These are useful anatomical associations rather than rules for every ulcer.
Frequently asked questions
Where is the superior (first) part of the duodenum located?
The superior (first) part of the duodenum lies begins near L1 in a supine adult and passes rightward, posteriorly and slightly superiorly from the pylorus.
What does the superior (first) part of the duodenum do?
Receives acidic chyme and participates in mixing it with alkaline secretions that protect the intestinal mucosa.
What are the parts of the superior (first) part of the duodenum?
A mobile proximal bulb or cap followed by a more fixed distal first portion; only the initial short segment is freely peritoneal on both surfaces.
What is the blood supply of the superior (first) part of the duodenum?
The superior (first) part of the duodenum is supplied by the variable supraduodenal and adjacent gastric branches, together with superior pancreaticoduodenal branches.