Duodenum Flashcards

Examine the four parts of the duodenum, their anatomical relations, peritoneal coverings, vascular supply, and digestive functions.

Card 1 of 30Question

What is the duodenum?

The first and shortest portion of the small intestine, extending from the pylorus to the duodenojejunal flexure.

In This Section

1. What is the duodenum?

The first and shortest portion of the small intestine, extending from the pylorus to the duodenojejunal flexure.

2. What is the approximate length of the adult duodenum?

Approximately 25 cm.

3. What are the four anatomical parts of the duodenum?

Superior, descending, horizontal, and ascending parts.

4. What is the general shape of the duodenum?

A C-shaped loop surrounding the head of the pancreas.

5. At approximately which vertebral level does the first part of the duodenum begin?

L1, near the transpyloric plane.

6. What is the approximate length of the superior first part of the duodenum?

Approximately 5 cm.

7. What is the duodenal bulb?

The dilated proximal portion of the superior duodenum, immediately distal to the pylorus.

8. Which part of the duodenum is most freely mobile and covered by peritoneum?

The proximal portion of the superior first part.

9. Which major structures lie posterior to the superior part of the duodenum?

The gastroduodenal artery, common bile duct, and portal vein.

10. What is the approximate length and vertebral extent of the descending second part of the duodenum?

About 7.5 to 10 cm, descending along the right side of L1 to L3.

11. Which major biliary and pancreatic ducts usually open into the descending duodenum?

The common bile duct and main pancreatic duct, usually through the hepatopancreatic ampulla.

12. What is the major duodenal papilla?

A mucosal elevation on the posteromedial wall of the descending duodenum where the hepatopancreatic ampulla opens.

13. Which pancreatic duct may open at the minor duodenal papilla?

The accessory pancreatic duct.

14. Which muscle regulates the flow of bile and pancreatic secretions through the major duodenal papilla?

The hepatopancreatic sphincter, also called the sphincter of Oddi.

15. At approximately which vertebral level does the horizontal third part of the duodenum cross the midline?

L3.

16. Which major blood vessels cross anterior to the horizontal part of the duodenum?

The superior mesenteric artery and vein.

17. Which major blood vessels lie posterior to the horizontal part of the duodenum?

The abdominal aorta and inferior vena cava.

18. What is the approximate course of the ascending fourth part of the duodenum?

It ascends to the left of the aorta from approximately L3 to L2, ending at the duodenojejunal flexure.

19. What is the suspensory muscle of the duodenum?

The muscle of Treitz, a fibromuscular structure supporting the duodenojejunal flexure.

20. How is most of the duodenum classified in relation to the peritoneum?

Secondarily retroperitoneal, except for the proximal superior part.

21. Which embryological gut divisions contribute to the duodenum?

The foregut forms the proximal duodenum, and the midgut forms the distal duodenum.

22. Which artery primarily supplies the proximal duodenum?

The superior pancreaticoduodenal arteries, arising from the gastroduodenal artery.

23. Which arteries primarily supply the distal duodenum?

The inferior pancreaticoduodenal arteries, arising from the superior mesenteric artery.

24. Why are the pancreaticoduodenal arterial arcades anatomically important?

They provide collateral circulation between the celiac trunk and superior mesenteric artery territories.

25. Through which venous system does blood from the duodenum drain?

The hepatic portal system through pancreaticoduodenal veins draining into the superior mesenteric and portal veins.

26. Which lymph nodes receive lymphatic drainage from the duodenum?

Pancreaticoduodenal and pyloric nodes, draining onward to celiac and superior mesenteric nodes.

27. Which autonomic plexuses provide sympathetic innervation to the duodenum?

The celiac and superior mesenteric plexuses.

28. Which nerve provides parasympathetic innervation to the duodenum?

The vagus nerve (cranial nerve X).

29. Why can a posterior duodenal ulcer cause severe hemorrhage?

It may erode the gastroduodenal artery behind the superior part of the duodenum.

30. What anatomical relationship is responsible for superior mesenteric artery syndrome?

Compression of the third part of the duodenum between the superior mesenteric artery and abdominal aorta.