Inferior mesenteric artery

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Inferior mesenteric artery
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Sigmoid colon and rectum, showing distribution of branches of inferior mesenteric artery and their anastomoses. (Inferior mesenteric artery labeled at center.)
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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.)
Details
Precursor Vitelline arteries
Source Abdominal aorta
Branches Left colic artery, sigmoid branches, superior rectal artery
Vein Inferior mesenteric vein
Supplies Large Intestine
Identifiers
Latin arteria mesenterica inferior
MeSH D017537
TA98 A12.2.12.069
TA2 4291
FMA 14750
Anatomical terminology

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. [1]

Contents

Structure

Origin

The IMA arises from the anterior aspect of the abdominal aorta. [2] [3]

The vertebral level of its origin is situated at L3 (subcostal plane), [2] [3] below the origins of the two renal arteries, [3] 3.8 cm (1 and a half inches) above the aortic bifurcation, [3] [2] at the level of the umbilicus (transumbilical plane), and posterior to the inferior border of the horizontal (III) part of the duodenum. [2]

Branches

Along its course, the IMA has the following branches: [1] [4] [3]

Branchnotes
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. [1] The IMV drains to the portal vein and does therefore not fully mirror the course of the IMA.[ contradictory ] [1] [4] [3]

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. [1] [4]

Clinical significance

The IMA and/or its branches must be resected for a left hemicolectomy. [5]

A horseshoe kidney, a common (1 in 500) anomaly of the kidneys, will be positioned below the IMA. [6] [7]

Additional images

See also

Superior mesenteric artery

References

  1. 1 2 3 4 5 Standring, Susan (2016). Gray's anatomy: the anatomical basis of clinical practice (41st ed.). Philadelphia: Elsevier Limited. ISBN   978-0-7020-5230-9. OCLC   920806541.
  2. 1 2 3 4 Sinnatamby, Chummy (2011). Last's Anatomy (12th ed.). p. 246. ISBN   978-0-7295-3752-0.
  3. 1 2 3 4 5 6 Drake, Richard L.; Vogl, Wayne; Mitchell, Adam W. M.; Gray, Henry (15 November 2015). Gray's anatomy for students (3rd ed.). Philadelphia, PA: Churchill Livingstone/Elsevier. ISBN   978-0-7020-5131-9. OCLC   881508489.
  4. 1 2 3 Moore, Keith L.; Dalley, Arthur F. II; Agur, A. M. R. (13 February 2013). Clinically oriented anatomy (7th ed.). Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins. ISBN   978-1-4511-1945-9. OCLC   813301028.
  5. 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.
  6. 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.
  7. "Clinical case: Horseshoe kidney transplantation". Kenhub. Retrieved 2019-09-28.