First (Superior) Part

extent of the first part of the duodenum?

• Extends from: pylorus → superior duodenal flexure

• Projection: at L1, right side of vertebral column

• Two parts:

  • Proximal part: intraperitoneal, inside the hepatoduodenal ligament → duodenal bulb 

  • Remaining part: secondary retroperitoneal, with coalescence fascia of Treitz

Anterior relations of the first part?

Gallbladder and quadrate lobe of liver.

Posterior relations of the first part?

common bile duct,

gastroduodenal artery,

portal vein,

and through the coalescence fascia with the IVC.

choledochus

Superior relation of the first part?

Insertion of lesser omentum (hepatoduodenal ligament) –

forms inferior limit of Winslow hiatus (epiploic foramen).

Inferior relation of the first part?

Head of pancreas

and duodenocolic ligament.