Duodenum

Anatomical features:

• length = 30 cm
• considered in terms of four parts:
  • first part
    • intraperitoneal
    • 5cm long
    • anatomical relationships:
      • inferior vena cava and bile duct pass posteriorly
  • second part
  • retroperitoneal
    • anatomical relationships:
      • course around the the head of the pancreas
      • ampulla of Vater in the second part
  • third part
  • retroperitoneal
    • anatomical relationships:
      • crosses anterior to the inferior cava, aorta and the origin of the inferior mesenteric artery
      • the superior mesenteric artery is anterior to the third part
  • fourth part
  • anatomical relationships:
    • passes upwards along the left side of the aorta and terminates at the ligament of Trietz (start of the jejunum)
      
      
• muscle layers - outer longitudinal and inner muscular layer
• Brunner's glands - most prominent in the proximal duodenum (alkaline secretions)