Descending (second) part of the duodenum

Overview

The second part of the duodenum descends along the right side of the pancreatic head. Its medial wall bears the major papilla, where bile and pancreatic secretion usually enter, and a more superior minor papilla when the accessory duct outlet is patent. Most of this segment is fixed against the posterior abdominal wall.

Reference facts

Location

Runs approximately from L1 to L3 on the right of the midline, lateral to the pancreatic head.

Parts

Bears the major and minor papillary regions on the medial wall; continues into the horizontal duodenum below.

Blood supply

Superior and inferior pancreaticoduodenal branches communicate in arcades, linking celiac and superior mesenteric inflow.

Innervation

Autonomic fibers arrive through celiac and superior mesenteric pathways, including vagal parasympathetic fibers.

Venous/Lymphatic drainage

Pancreaticoduodenal veins drain toward portal and superior mesenteric channels; lymph passes through pancreaticoduodenal nodes toward celiac and superior mesenteric groups.

Relations

The pancreatic head is medial; the right renal region, ureter and vena cava are posterior relations, while the transverse mesocolon crosses anteriorly.

Function

Combines gastric contents with bile and pancreatic enzymes while neutralization, digestion and absorption proceed.

Frequently asked questions