In
human anatomy, the inferior mesenteric artery, often abbreviated as IMA, is the third main branch of the
abdominal aorta
In human anatomy, the abdominal aorta is the largest artery in the abdominal cavity. As part of the aorta, it is a direct continuation of the descending aorta (of the thorax).
Structure
The abdominal aorta begins at the level of the diaphr ...
and arises at the level of
L3, supplying the
large intestine from the distal transverse colon to the upper part of the anal canal. The regions supplied by the IMA are the
descending colon, the
sigmoid colon, and part of the rectum.
Structure
Proximally, its territory of distribution overlaps (forms a
watershed
Watershed is a hydrological term, which has been adopted in other fields in a more or less figurative sense. It may refer to:
Hydrology
* Drainage divide, the line that separates neighbouring drainage basins
* Drainage basin, called a "watershe ...
) with the
middle colic artery
The middle colic artery is an artery of the abdomen; a branch of the superior mesenteric artery distributed to parts of the ascending and transverse colon. It usually divides into two terminal branches - a left one and a right one - which go on ...
, and therefore the
superior mesenteric artery. The SMA and IMA anastomose via the
marginal artery of the colon (artery of Drummond) and via
Riolan's arcade
In human anatomy, the marginal artery of the colon, also known as the marginal artery of Drummond, the artery of Drummond, and simply as the marginal artery, is an artery that connects the inferior mesenteric artery with the superior mesenteric ...
(also called the "meandering artery", an arterial connection between the left colic artery and the middle colic artery). The territory of distribution of the IMA is more or less equivalent to the embryonic
hindgut.
Branches
The IMA branches off the anterior surface of the
abdominal aorta
In human anatomy, the abdominal aorta is the largest artery in the abdominal cavity. As part of the aorta, it is a direct continuation of the descending aorta (of the thorax).
Structure
The abdominal aorta begins at the level of the diaphr ...
below the
renal artery
The renal arteries are paired arteries that supply the kidneys with blood. Each is directed across the crus of the diaphragm, so as to form nearly a right angle.
The renal arteries carry a large portion of total blood flow to the kidneys. Up to ...
branch points, 3-4 cm above the
aortic bifurcation (into the
common iliac arteries) at the L3 vertebral level.
Along its course, the IMA has the following branches:
All these arterial branches further divide into
arcades which then supply the
colon at regular intervals.
Associated veins
The IMA is accompanied along its course by a similarly named
vein
Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated ...
, the
inferior mesenteric vein
In human anatomy, the inferior mesenteric vein (IMV) is a blood vessel that drains blood from the large intestine. It usually terminates when reaching the splenic vein, which goes on to form the portal vein with the superior mesenteric vein (SM ...
, which drains into the
splenic vein.
The IMV therefore drains to the
portal vein and does not fully mirror the course of the IMA.
Clinical significance
The IMA and/or its branches must be resected for a left hemicolectomy.
A
horseshoe kidney, a common (1 in 500) anomaly of the kidneys, will be positioned below the IMA.
Additional images
File:Gray531.png, The abdominal aorta and its branches.
File:Gray537.png, The inferior mesenteric artery and its branches.
File:Gray847.png, Abdominal portion of the sympathetic trunk, with the celiac plexus and hypogastric plexus.
File:Gray1042.png, Duodenojejunal fossa.
File:Gray1121.png, Posterior abdominal wall, after removal of the peritoneum, showing kidneys, suprarenal capsules, and great vessels.
File:Gray1227.png, Front of abdomen, showing surface markings for arteries and inguinal canal.
File:Slide4nn.JPG, Inferior mesenteric artery
File:Slide2erer.JPG, Lumbar and sacral plexus. Deep dissection.Anterior view.
File:Slide1ewew.JPG, Lumbar and sacral plexus. Deep dissection.Anterior view.
File:Slide2ewew.JPG, Lumbar and sacral plexus. Deep dissection.Anterior view.
References
External links
Lotti M. Anatomy in relation to left colectomy* - "Branches of the inferior mesenteric artery."
* - "Posterior Abdominal Wall: Branches of the Abdominal Aorta"
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* - "Posterior Abdominal Wall, Dissection, Anterior View"
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{{Authority control
Arteries of the abdomen