Inferior mesenteric artery

The inferior mesenteric artery (IMA) is an anterior branch of the abdominal aorta that supplies the hindgut. It is the smallest of the three anterior branches of the abdominal aorta.

Gross anatomy

Location
  • within the mesentery of the hindgut
Origin
  • unpaired vessel from the anterior aspect of the abdominal aorta at L3 level
Course

The IMA runs obliquely downwards towards the pelvic brim, initially anterior and then to the left of the aorta. After giving off the left colic and sigmoid arteries, it crosses the origin of the left common iliac artery medial to the ureter, with the inferior mesenteric vein lying between the two. Within the pelvis, it continues as the superior rectal artery in the root of the sigmoid mesocolon.

Branches
Supply
  • splenic flexure of large bowel to the upper two thirds of the rectum
Relations

The left colic and sigmoid branches of the IMA cross anterior to the ureter

Variant anatomy

  • doubled IMA
  • absent IMA
  • common trunks (e.g. left colic and rectosigmoid, rectal and colosigmoid)
  • absent left colic branch
  • Arc of Riolan (SMA/IMA connection)
Anatomy: Abdominopelvic
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Article information

rID: 12485
Section: Anatomy
Tag: cases, cases
Synonyms or Alternate Spellings:
  • Inferior mesenteric artery (IMA)
  • IMA

Cases and figures

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    Figure 1: inferior mesenteric artery (Gray's illustration)
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    Figure 2: branches of the abdominal aorta
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