The Duodenum
Definition
The first part of the small intestine
Followed by the jejunum
Widest and shortest part of the small intestine
C shaped
Situation
Lies in the upper abdomen near the midline
Parts
The pylorus of the stomach leads to the duodenum.
4 parts
- The first part or duodenal bulb (5 cm)
Connected to the undersurface of the liver (porta hepatis) by
hepaticoduodenal ligament containing the hepatic artery, portal vein and common bile duct
- The second part (descending part) (10 cm)
- The third part (horizontal part) (7.5 cm) : runs from right to left in front of the IVC and aorta with superior mesenteric vessels in front of it
- The fourth part (ascending part) 2.5 cm. continues as jejunum
Duodenojejunal junction attached to the wall by Treitz Ligament
2nd, 3rd and 4th part retroperitoneal.
Into the 2nd part opens the Pancreaticobiliary duct, through the ampulla of Vater
The opening is controlled by Sphincter of Oddi
Associated Structures
The relations of the duodenal C is depicted in the picture
Blood Supply
Arterial Supply
Right gastric artery & right gastro-epiploic artery
Gastroduodenal artery
Branches from superior mesenteric artery
Venous drainage
Into the portal vein
Nerve Supply
vagus nerves - Parasympathetic
Coeliac plexus - Sympathetic
Lymph Drainage
Pancreaticoduodenal, supra and infrapyloric, superior mesenteric, mesocolic and coeliac lymph nodes.
Applied Anatomy
I part of duodenum : Chronic Duodenal Ulcer
II part of duodenum : Carcinoma of Ampulla of Vater (cancer)
