Duodenum Flashcards
What part of the small intestine is the duodenum?
It is most proximal portion of the small intestine
What is the shape of the duodenum?
C-shaped
Direction of the duodenum
It runs from the pylorus of the stomach to the duodenojejunal junction. It wraps around the head of the pancreas.
Length of the duodenum
25cm long
Parts of the duodenum
The duodenum can be divided into four parts; superior, descending, inferior and ascending
Location of Superior part of duodenum
Spinal level L1
What is the first section of the duodenum known as?
The cap
Direction of the superior duodenum?
It ascends upwards from the pylorus of the stomach
What connects the superior duodenum to the liver?
Hepatoduodenal ligament
Most common site of duodenal ulceration
Superior duodenum
What part of the duodenum is intraperitoneal?
The initial 3cm of the superior duodenum is covered anteriorly and posteriorly by visceral peritoneum (intraperitoneal), with the remainder retroperitoneal (only covered anteriorly).
Location of the descending duodenum (spinal)
L1 - L3
Direction of descending duodenum
The descending portion curves inferiorly around the head of the pancreas
Location of descending duodenum
It lies posteriorly to the transverse colon, and anterior to the hilum of the right kidney.
What marks the descending duodenum internally?
Internally, the descending duodenum is marked by the major duodenal papilla (bile and pancreatic duct) - the opening at which bile and pancreatic secretions to enter from the ampulla of Vater (hepatopancreatic ampulla).
Spinal level of inferior (horizontal) duodenum
L3
Direction of inferior (horizontal) duodenum
The inferior duodenum travels laterally to the left, crossing over the inferior vena cava and aorta
Location of inferior (horizontal) duodenum
It is located inferiorly to the pancreas, and posteriorly to the superior mesenteric artery and vein.
Spinal location of ascending duodenum
L3-L2
Direction of the ascending duodenum
After the duodenum crosses the aorta, it ascends and curves anteriorly to join the jejunum at a sharp turn known as the duodenojejunal flexure.
Duodenojejunal flexure.
Sharp turn where duodenum joins jejunum anteriorly after the duodenum crosses the aorta
Slip of muscle at the duodenojejunal junction
The suspensory muscle of the duodenum (or ligament of Treitz)
Function of the suspensory muscle of the duodenum
Contraction of this muscle widens the angle of the flexure, and aids movement of the intestinal contents into the jejunum.
The arterial supply of the duodenum
The arterial supply of the duodenum is derived from two sources:
Proximal to the major duodenal papilla - gastroduodenal artery (branch of the coeliac trunk).
Distal to the major duodenal papilla - pancreaticoduodenal artery (branch of superior mesenteric artery).
Which parts of the duodenum are mobile?
The superior part and ascending part
