NEET PG Medical – 2015 – Question – 71
All are true about 1st part of duodenum, except ?
a) 5 cm long
b) Is superior part
c) Develops from foregut
d) Supplied by superior mesenteric artery
Show Answer
Correct Answer – D
Ans. is ‘D’ i.e., Supplied by superior mesenteric artery Duodenum
- Duodenum is ‘C’ shaped, shortest, widest and most fixed part of small intestine. It is 25 cm long. It is devoid of mesentery. Most of the duodenum is retroperitoneal and fixed, except at its two ends where it is suspended by folds of peritoneum, and is therefore mobile. Duodenum lies opposite L1, L2 and L3 vertebrae.
- Duodenum is C-shaped curve which encloses the head of pancreas and is subdivided into four parts :
1. First part (Superior part) : It is 5 cm (2 inches) long. It begins at the pylorus and meet the second part at superior duodenal flexure.
This part appears as duodenal cap on barium studies.
2. Second part (Descending part) : It is about 7.5 cm (3 inches) long.
It is vertical part which begins at superior duodenal flexure and meet the third part at inferior duodenal flexure. The interior of second part of duodenum shows following features :
i) Major duodenal papilla : It is present 8-10 cm distal to the pylorus.
The hepatopancreatic ampulla or ampulla of Vater (joint part of bile duct and pancreatic duct) opens here.
ii) Minor duodenal papilla : It is present 6-8 cm distal to the pylorus.
Accessory pancreatic duct opens here.
3. Third part (Horizonal part) : It is 10 cm (4 inches) long. It begins at inferior duodenal flexure and passes towards the left in front of IVC behind superior mesenteric vessels and root of mesentery to meet 4th part of duodenum.
Fourth part : It is 2-5 cm (1 inches) long and runs upward immediately to the left of aorta. It ends at duodenojejunal flexure by joining the jejunum.
Arterial supply
The part of duodenum before the opening of bile duct (major duodenal papilla) develops from foregut and therefore is supplied by coeliac trunk through superior pancreaticoduodenal artery, a branch of gastroduodenal artery, which in turn is a branch of common hepatic artery. Part of duodenum distal to opening of bile duct is developed from midgut and therefore is supplied by superior mesenteric artery through inferior pancreatic duodenal artery. First part of duodenum receives additional supply from right gastric artery, supraduodenal artery (a branch of common hepatic artery), retro-duodenal branch of gastroduodenal artery and right gastropiploic artery.
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