Inferior mesenteric artery
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- The inferior mesenteric artery is the artery of the hindgut
- Supplies the bowel from the left third of the transverse colon to the upper part of the anal canal.
Course and Relations
- It arises from the front of the aorta at the level of the body of L3 (the subcostal plane).
- It appears from under the horizontal part of the duodenum
- It descends obliquely to the left, towards the middle of the left common iliac artery.
- From the middle of the left common iliac artery, the inferior mesenteric artery descends in front of the left sympathetic trunk and psoas major
- It enters the apex of the sigmoid mesocolon as the superior rectal artery.
- The inferior mesenteric vein lies on its left side
Branches and Distribution
- The branches of the inferior mesenteric artery come off its left side.
- They form an anastomotic trunk alongside the colon- marginal artery (of Drummond) that extends from the ileocaecal junction to the distal end of the sigmoid colon.
- The anastomosis between the left colic (of the inferior mesenteric) is usually a good one.
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| Branches of inferior mesenteric artery |
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Left colic artery
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Arises 2.5-5 cm below the upper end of the trunk
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It may lie superficial or deep to the inferior mesenteric vein.
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Near the descending colon, it divides into ascending and descending branches, which take part in the formation of the marginal artery.
The ascending branch
Sigmoid arteries
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Two or three in number
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Descend obliquely to the left.
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Each divides into ascending and descending branches which contribute to the marginal artery,
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The descending branch anastomoses with the superior rectal artery.
superior rectal artery
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Pelvic continuation of the inferior mesenteric artery below the middle of the left common iliac artery.
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curves medially in the sigmoid mesocolon and, reaching the upper end of the rectum
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Divides into right and left branches. The right branch divides into anterior and posterior branches.
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