Small Intestine Anatomy Quiz: Duodenum and Jejunum Study

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Questions and Answers

What is the total length of the duodenum?

25 cm (correct)

10 inches

15 inches

30 cm

Which part of the duodenum is intraperitoneal (movable)?

First inch of the superior duodenum (correct)

Third part (horizontal)

Fourth part (ascending)

Second part (descending)

What structure does the duodenum wrap around?

Stomach

Liver

Kidney

Pancreas (correct)

Which part of the duodenum is the most common site of duodenal ulceration?

First part (superior) Signup and view all the answers

What structure is the duodenum connected to by the hepatoduodenal ligament?

Liver Signup and view all the answers

Which part of the duodenum lies posterior to the transverse colon and anterior to the right kidney?

Second part (descending) Signup and view all the answers

Which part of the duodenum is marked by the major duodenal papilla?

Second part Signup and view all the answers

Which vessel does the third part of the duodenum cross over?

Both a and b Signup and view all the answers

What is the name of the sharp turn where the duodenum joins the jejunum?

Duodenojejunal flexure Signup and view all the answers

What is the function of the suspensory muscle of the duodenum?

All of the above Signup and view all the answers

Where does the suspensory muscle of the duodenum originate?

From the right crus of the diaphragm Signup and view all the answers

What is the location of the fourth part of the duodenum?

After crossing the aorta, it ascends and curves anteriorly to join the jejunum Signup and view all the answers

Which part of the duodenum is intraperitoneal?

First inch of the first part Signup and view all the answers

Which duct opens into the medial wall of the second part of the duodenum?

Both common bile duct and pancreatic duct Signup and view all the answers

What is the anterior relation of the third part of the duodenum?

Superior mesenteric artery Signup and view all the answers

How is the fourth part of the duodenum attached to the diaphragm?

By the suspensory ligament Signup and view all the answers

Which arteries supply the fourth part of the duodenum?

Superior and inferior pancreaticoduodenal arteries Signup and view all the answers

Study Notes

Duodenum Structure

The duodenum is the most proximal part of the small intestine, derived from the Latin "duodenum digitorum" meaning twelve fingers length.
It is about 25cm long and wraps around the head of the pancreas in a "C" shape.

Four Parts of the Duodenum

First Part: 2 inches long, located at the level of L1 (transpyloric plane), and ascends upwards from the pylorus of the stomach.
Second Part: 3 inches long, descends from L1 to L3, and curves inferiorly around the head of the pancreas.
Third Part: 4 inches long, located at L3 (subcostal plane), and travels laterally to the left, crossing over the inferior vena cava and aorta.
Fourth Part: 1 inch long, ascends from L3 to L2, and curves anteriorly to join the jejunum at the duodenojejunal flexure.

First Part of the Duodenum

The first inch of the superior duodenum is intraperitoneal (movable part), and the remainder is retroperitoneal (only covered anteriorly).
It is connected to the liver by the hepatoduodenal ligament.
The first part is the most common site of duodenal ulceration.

Second Part of the Duodenum

The descending duodenum is marked by the major duodenal papilla, which is the opening at which bile and pancreatic secretions enter from the ampulla of Vater (hepatopancreatic ampulla).

Third Part of the Duodenum

It lies inferiorly to the pancreas and posteriorly to the superior mesenteric artery and vein.
It has an important anterior relation, the superior mesenteric artery, which if aneurysmal (enlarged), can compress the horizontal part of the duodenum, causing nausea and digestive problems.

Fourth Part of the Duodenum

It is attached to the diaphragm by the suspensory ligament of the duodenum (or ligament of Treitz).
The suspensory muscle of the duodenum contracts to widen the angle of the flexure, aiding movement of intestinal contents into the jejunum.

Arterial Supply

Above the major duodenal papilla, it is supplied by the superior pancreaticoduodenal artery.
Below the major duodenal papilla, it is supplied by the inferior pancreaticoduodenal artery.

Venous Drainage

The veins of the duodenum drain into the splenic vein, superior mesenteric vein, and portal vein.

Lymphatic Drainage

Pancreaticoduodenal nodes, hepatic nodes, coeliac nodes, and cisterna chyli are involved in lymphatic drainage.

Nerve Supply

Sympathetic nerves: T9 and T10
Parasympathetic nerves: Vagus

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Description

Learn about the structure and parts of the duodenum, the most proximal portion of the small intestine. Explore the fixed and movable sections, as well as the divisions of the duodenum into four parts.