Duodenum

Question 1

Superior duodenum (aka ampulla or duodenal cap)

Answer 1

• Lies at the transpyloric plane (L1)
• SMOOTH wall
• Duodenal ulcers (95%) occurs in posterior wall of superior duodenum and can lead to:
  1) Gastroduodenal artery rupture
  2) Liver and gallbladder ulceration
• Suspended by hepatoduodenal ligament (first 2-3cm of duodenum is intraperitoneal)

Important relations:
Anterior:
1) Caudate process of liver
2) Gallbladder

Posterior:

1) Bile duct
2) Hepatic portal vein
3) IVC
4) Gastroduodenal artery

Question 2

Descending duodenum

Answer 2

• L1-L3
• Plicae circularis
• Contains 2 major openings:
  1) Accessory pancreatic duct opening into minor duodenal papilla
  2) Hepatopancreatic ampulla opening into major duodenal papilla (marks boundary between foregut and midgut)
• Most common site for diverticula (outpouching of mucosa through wall)

Important Relations:
Anterior:
1) Transverse colon and mesocolon

Posterior:
1) Hilum of right kidney

Question 3

Inferior/Horizontal Duodenum

Answer 3

• L3
• Plicae circularis
• Fistula may occur between aorta and duodenum (e.g. surgery)

Important relations:
Anterior:
1) SMA
2) SMV

Posterior:

1) Aorta
2) IVC

Question 4

Ascending duodenum

Answer 4

• L3-L2
• Plicae circularis
• Ligament of Trietz (suspensory muscle of duodenum) located at duodenojejunal flexure – contraction of this muscle aids movement of content into jejunum

Question 5

Vasculature

Answer 5

Arterial:
Branches of gastroduodenal artery:
1) Supraduodenal
2) Right gastroepiploic/gastro-omental
3) Anterior and posterior superior pancreaticoduodenal arteries 

Branches of superior mesenteric artery:
1) Anterior and posterior inferior pancreaticoduodenal arteries

Venous:
1) Major veins eventually drain into hepatic portal vein

Question 6

Lymphatics

Answer 6

Superior to major duodenal papilla:
-From superior pancreaticoduodenal nodes to gastroduodenal nodes (and eventually into coeliac node)

Inferior to major duodenal papilla:
-From inferior pancreaticoduodenal nodes to superior mesenteric node

Question 7

Whipple Procedure

Answer 7

• Head of pancreas leads to surgical removal of:
  1) Common bile duct
  2) Gallbladder
  3) Head of pancreas
  4) Duodenum