Inferior mesenteric artery

In human anatomy, the inferior mesenteric artery, often abbreviated as 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.[1]

Inferior mesenteric artery
Sigmoid colon and rectum, showing distribution of branches of inferior mesenteric artery and their anastomoses. (Inferior mesenteric artery labeled at center.)
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.)
Precursorvitelline arteries
Sourceabdominal aorta
Branchesleft colic artery, sigmoid branches, superior rectal artery
Veininferior mesenteric vein
Latinarteria mesenterica inferior
Anatomical terminology

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 medial colic artery). The territory of distribution of the IMA is more or less equivalent to the embryonic hindgut.[1][2]


The IMA branches off the anterior surface of the abdominal aorta below the renal artery branch points, 3-4 cm above the aortic bifurcation (into the common iliac arteries) at the L3 vertebral level.[3]

Along its course, the IMA has the following branches:[1][2][3]

left colic arterysupplies descending colon
sigmoid branchesthe most superior being described as 'the superior sigmoid artery'
superior rectal arteryeffectively 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.

Associated veins

The IMA is accompanied along its course by a similarly named vein, the inferior mesenteric vein, which drains into the splenic vein.[1]

The IMV therefore drains to the portal vein and does not fully mirror the course of the IMA.[1][2][3]

Surgery and pathology

The IMA and/or its branches must be resected for a left hemicolectomy.[4]

A horseshoe kidney, a common (1 in 500) anomaly of the kidneys, will be positioned below the IMA.[5][6]

Additional images


  1. Standring, Susan. Gray's anatomy : the anatomical basis of clinical practice (41st ed.). Philadelphia: Elsevier Limited. ISBN 9780702052309. OCLC 920806541.
  2. Moore, Keith L.; Dalley, Arthur F., II; Agur, A. M. R. Clinically oriented anatomy (7th ed.). Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins. ISBN 1451119453. OCLC 813301028.
  3. Drake, Richard L.; Vogl, Wayne; Mitchell, Adam W. M.; Gray, Henry. Gray's anatomy for students (3rd ed.). Philadelphia, PA: Churchill Livingstone/Elsevier. ISBN 9780702051319. OCLC 881508489.
  4. Charan, Ishwar; Kapoor, Akhil; Singhal, Mukesh Kumar; Jagawat, Namrata; Bhavsar, Deepak; Jain, Vikas; Kumar, Vanita; Kumar, Harvindra Singh (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. 77 (Suppl 3): 1103–1108. doi:10.1007/s12262-014-1179-2. ISSN 0972-2068. PMC 4775673. PMID 27011519.
  5. Schiappacasse, G; Aguirre, J; Soffia, P; Silva, C S; Zilleruelo, N (January 2015). "CT findings of the main pathological conditions associated with horseshoe kidneys". The British Journal of Radiology. 88 (1045). doi:10.1259/bjr.20140456. ISSN 0007-1285. PMC 4277381. PMID 25375751.
  6. "Clinical case: Horseshoe kidney transplantation". Kenhub. Retrieved 2019-09-28.
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