Prof. Dr. Selda Önderoğlu DUODENUM

DUODENUM

Prof. Dr. Selda Önderoğlu

SMALL INTESTINE:

Extends from pylorus to ileocecal junction.

3 parts:

1-duodenum 2-jejunum 3-ileum.

Duodenum is the shortest, Widest, thickest walled and least movable part of small intestines

Duodenum :

• Like a C-shaped tube, about 25cm long

• Location: epigastric and umbilical regions

• Curves around the head of pancreas.

• It has the openings of the bile and pancreatic ducts.

• Divided into 4 parts:

• SUPERIOR (1st)

• DESCENDING (2nd)

• HORIZONTAL (3rd)

• ASCENDING (4th)

• only ampulla is intraperitoneal

• other parts: retroperitoneal

1st ( superior) part

- It is 5cm long .

- ampulla (Bulb)- the first half of the 1st part of duod.

- It begins at the pylorus and runs upward and backward on the right side of the L1 vertebra .

- It lies on the transpyloric plane.

- Relations:

• Anterior:quadrate lobe of the liver, gallbladder.

• Posterior:lesser sac, gastroduodenal artery,bile duct and portal vein , inferior vena cava.

• Superior: epiploic foramen

• Inferior: head of the pancreas.

THE SUPERIOR (FIRST) PART

THE DESCENDING (Second) PART

2

part of duodenum:

• Length:8 cm

• on the right side of the 2^nd and 3^rd lumbar vertebrae.

• On medial border:

major duodenal papilla : common bile duct + main pancreatic duct unite- forms hepatopancreatic ampulla-opens to papilla.

minor duodenal papilla: accessory pancreatic duct (if present) opens here.

Relations:

Anteriorly : gallbladder, right lobe of the liver, transverse colon and coils of small intestine .

Posteriorly : right kidney, right ureter

Laterally: ascending colon, right colic flexure, right lobe of liver Medially: head of pancreas, bile duct,main pancreatic duct.

BILE and PANCREATIC DUCTS

THE HORIZONTAL (Inferior) PART

3

(horizontal)part

• Length:8cm;

• Course: horizontally to the left on the subcostal plane , at lower margin of pancreas.

• Relations:

Anteriorly:root of mesentery(superior mesenteric vessels within it), coils of jejunum.

• Posteriorly :right ureter, right psoas major muscle , inferior vena cava, aorta, inf. Mesenteric av,testicular (ovarian) av

• Superiorly: head of pancreas .

• Inferiorly : Coils of jejunum.

4

( ascending)part

• Length:5cm

• Course:upwards and to the left to the duodenojejunal flexure (This flexure is held in position by a peritoneal fold , the suspensory muscle of diaphragm (ligament of Treitz) , attached to the right crus of diaphragm.

• Relations:

Anteriorly: root of the mesentery,coils of jejunum.

Posteriorly: left margin of aorta, left psoas major

muscle .

Suspensory muscle of duodenum-LIGAMENT OF TREITZ

STRUCTURE OF THE DUODENUM

Duodenum: blood supply ,lymph drainage and nerve supply:

Blood supply : - Arteries :

- superior pancreaticoduodenal artery (br. of gastroduodenal a. )

- inferior pancreaticoduodenal artery (br. of superior mesenteric a.).

- Veins:

- superior pancreaticoduodenal vein drains into portal vein - inferior vein joins the superior mesenteric vein.

- Splenic v

• Lymph drainge:

- celiac nodes and superior mesenteric nodes

• Nerve supply:

-sympathetic and parasympathetic (vagus) nn: from coeliac and superior mesenteric plexuses.

-

VESSELS OF DUODENUM

veins

Peritoneum and

DUODENAL RECESSES

-superior -inferior

- paraduodenal

- retroduodenal

LYMPHATICS

INNERVATION