First (Superior) Part

extent of the first part of the duodenum?

from pylorus to superior duodenal flexure.

Anterior relations of the first part?

Gallbladder and quadrate lobe of liver.

Posterior relations of the first part?

Gastroduodenal artery,

portal vein,

and 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.