Duodenmum Flashcards
Duodenum is ____ cm long
25cms
It starts and ends at :
Begins at the pylorus @ Transpyloric plane 2.5cms right of midline and ends at duodenojejununal junction 2.5cms left of midline just below transpyloric plane
The ‘C’ shape of duodenum encloses _____
The head of pancreas
Duodenum is located at which level in abdominal cavity :
Above the level of umbilicus at L1 L2 L3 Vertebrae
Parts of Duodenum :
- Superior ( First Part ) : 5cms
- Descending ( Second Part ) : 7.5cms
- Horizontal ( Third Part ) : 10cms
- Ascending ( Fourth Part ) : 2.5cms
The course of First Part :
Begins at the Pylorus from where it goes upwards and backwards towards the right side of vertebrae till it reaches the neck of gall bladder from where it curves downwards to form the 2nd Part ( Superior Duodenal Flexure )
The Features of First Part :
- The first part of duodenum is partly retroperitoneal
- It develops from foregut
- It is freely mobile and distensible
- Has no circular folds in the lumen in the first 2.5cms
- Site for duodenal ulcer
- Supplied by branches of celiac artery
Relations of First Part :
Anteriorly : Quadrate lobe of liver ; Gall Bladder
Posteriorly : Portal vein, Bile duct, Gastroduodenal Artery
Superiorly : Epiploic Foramen
Inferiorly : Head and neck of pancreas
The Course of Second Part :
Begins at superior duodenal flexrue and moves downwards in front of medial part of Right Kidney till the lower border of L3 Vertebrae from where it curves to left forming Inferior Duodenal Flexure
Features of First Part :
- Upper Half Develops from Foregut and Lower Half Develops from Midgut
- Lies Behind Transverse Colon
- Receives Bile Duct and Chief and Accessory Pancreatic Duct
- Only part of intestine supplied by double row of vasa recta arising from ant. and post. pancreaticoduodenal arterial arcades
Relations of Second Part :
Anterior : Rigth lobe of Liver ; Gall Bladder; Transverse Colon and Mesocolon
Posterior : Right Kidney and Right Renal Vessels; and Right Part of IVC and Right Psoas Major Muscle
Medially : Head of Pancreas
Laterally : Ascending Colon; Right Colic Flexure ; Right Lobe of Liver
The Course Of Third Part :
Runs horizontally from Inf. Duodenal Flexure at the level of lower border of L3, in front of IVC And then takes a smooth curve upwards
Relations of Third Part :
Anterior : Root Of Mesentery, Coils of Jejunum, Superior Mesenteric Arteries
Posterior : Right Psoas major muscles; Rt. Ureter , IVC, Abdominal Aorta and Rt Gonad Vessels
Superior : Head of Pancreas with Unicate process
Inferior : Coils of Jejunum
Course of Fourth Part :
From the third part it runs upwards on the left of Abdominal Aorta till the upper border of L2 from where it comes forwards i.e ventrally to continue as jejunum
Relations of Fourth Part :
Anterior : Transverse Colon and Mesocolon
Posterior : Lt Psoas Major, Lt . Gonad Vessels , Inferior Mesenteric Artery
Superior : Body of pancreas
On Left : Lt. Kidney and Ureter
On Right : Abdominal Aorta
The mucous membrane of the duodenum presents circular folds called ___ which start at
Valves of Kerckring
Starts in the second part of duodenum
Special features in the interior of second part :
- Major duodenal papillae
- Minor duodenal Papillae
- Arch of plica semicircularis
- Plica longitudinalis
What is Major Duodenal Papillae
Well marked conical projection and the posteromedial surface of 2nd part of duodenum; On its summit opens the common hepatiopancreatic Duct
What is Minor Duodenal Papillae
Small conical projection near the major duodenal papillae; On its summit opens the accessory pancreatic duct.
Arch of Plica semicircularis :
Plica semicircularis forms an arch over Major duodenal papillae like a hood called Monks Hood
Plica Longitudinalis :
Vertical Tortuous fold extending downwards from Major duodenal papillae
The suspensory ligament, which suspends the duodenojejunal flexure to the right crus of diaphragm is called
Ligament Of Treitz
What is duodenal Recess
In the region of duodenojejunal junction, small pocket like pouches of peritoneum called duodenal recesses occur
Important peritoneal recesses
Superior duodenal recess Inferior duodenal recess Paraduodenal Recess Retroduodenal Recess Mesenteroparietal recess
Superior Duodenal Recess location:
It lies to the left upper end of the fourth part of the duodenum, behind the superior duodenojejunal peritoneal fold with its mouth looking downward
Inferior Duodenal Recess
It lies a little below the superior recess behind the inferior duodenojejunal peritoneal fold with its orifice looking upward.
Paraduodenal Recess
It is the lowest when present. It lies
to the left of the fourth part of the duodenum behind the paraduodenal fold of the peritoneum with its orifice facing medially. “The paraduodenal fold contains inferior mesenteric vein in its free border” edge.
Retroduodenal Recess
It is the largest of duodenal
recesses, but is rarely present. If present, it lies behind the third and fourth parts of the duodenum. Its orifice looks downward and to the left
Mesenteroparietal Recess
It is found only in 1%
individuals. It lies below the duodenum behind the upper part of the mesentery. The superior mesenteric vessels lie in the anterior wall of its opening.
Arterial Supply
Upper Half Supplied By : Celiac Trunk
Lower Half Supplied By : Superior Mesenteric Artery
- Superior Pancreatoduodenal Artery ( B. of Celiac Trunk )
- Inferior Pancreatoduodenal Artery ( B. of S. Mesenteric Artery )
These 2 arteries each divided into anterior and posterior branches; Each respective branches form anastomosis to form anterior posterior pancreaticoduodenal arcades
Each arcade forms a vasa recta
- Supraduodenal artery of “Wilkie” ( Branch of gastroduodenal branch of Celiac trunk supplying ant. and post. part of first part of duodenum )
- Retroduodenal branches of the gastroduodenal artery.
- Leash of branches of the hepatic artery.
- Branches from the right gastroepiploic artery.
7. Artery from the first jejunal branch of the superior mesenteric artery ( Supplies the 4th Part )
Venous drainage :
Veins corresponds to the arteries but are superficial compared to them and drain into Splenic, Superior Mesenteric and Portal Vein
LYMPHATIC DRAINAGE :
Drain into pancreaticoduodenal nodes lying along the inner curve of the duodenum
Nerve Supply :
Sympathetic nerves to the duodenum are derived from :T6–T9 segments
Parasympathetic nerves from both the vagi through coeliac and superior mesenteric plexuses.
