Anatomy of the duodenum
The third part of the duodenum runs horizontally, passing in front of the following structures as it runs from the left to the right side of the abdominal midline:
Right Psoas Major muscle
Inferior Vena Cava (IVC)
Abdominal Aorta
Left Psoas Major muscle
This part of the duodenum is anterior to the right Ureter and Gonadal vessels.
This part is posterior to the Superior Mesenteric vein & artery, as well as the root of the Mesentery.
