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Inferior mesenteric artery

Branch of the abdominal aorta supplying part of the large intestine

Field	Value
Name	Inferior mesenteric artery
Latin	arteria mesenterica inferior
Image	Gray538.png
Caption	Sigmoid colon and rectum, showing distribution of branches of inferior mesenteric artery and their anastomoses. (Inferior mesenteric artery labeled at center.)
Image2	gray985.png
Caption2	Abdominal part of digestive tube and its attachment to the primitive or common mesentery. Human embryo of six weeks. (Inferior mesenteric artery labeled at bottom right.)
BranchFrom	Abdominal aorta
BranchTo	Left colic artery, sigmoid branches, superior rectal artery
Vein	Inferior mesenteric vein
Precursor	Vitelline arteries
Supplies	Large Intestine

In human anatomy, the inferior mesenteric artery (IMA) is the third main branch of the abdominal aorta 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

Origin

The IMA arises from the anterior aspect of the abdominal aorta.****

The vertebral level of its origin is situated at L3 (subcostal plane),**** below the origins of the two renal arteries, 3.8 cm (1 and a half inches) above the aortic bifurcation,**** at the level of the umbilicus (transumbilical plane), and posterior to the inferior border of the horizontal (III) part of the duodenum.****

Branches

Along its course, the IMA has the following branches:

Branch	notes
left colic artery	supplies descending colon
sigmoid branches	the most superior being described as 'the superior sigmoid artery'
superior rectal artery	effectively the terminal branch of the IMA (the continuation of the IMA after all other branches)

All these arterial branches further divide into arcades which then supply the colon at regular intervals.

Relations

The IMA is accompanied along its course by a similarly named vein, the inferior mesenteric vein, which drains into the splenic vein. The IMV drains to the portal vein and does therefore not fully mirror the course of the IMA.

Distribution

Proximally, its territory of distribution overlaps (forms a watershed) with the middle colic artery, 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 (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.

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

Standring, Susan. (2016). "Gray's anatomy: the anatomical basis of clinical practice". Elsevier Limited.
Sinnatamby, Chummy. (2011). "Last's Anatomy".
(15 November 2015). "Gray's anatomy for students". Churchill Livingstone/Elsevier.
(13 February 2013). "Clinically oriented anatomy". Wolters Kluwer Health/Lippincott Williams & Wilkins.
(December 2015). "High Ligation of Inferior Mesenteric Artery in Left Colonic and Rectal Cancers: Lymph Node Yield and Survival Benefit". The Indian Journal of Surgery.
(January 2015). "CT findings of the main pathological conditions associated with horseshoe kidneys". The British Journal of Radiology.
"Clinical case: Horseshoe kidney transplantation".

Info: Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

arteries-of-the-abdomen

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