Inferior mesenteric artery

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.)
Details
Precursor	vitelline arteries
Source	abdominal aorta
Branches	left colic artery, sigmoid branches, superior rectal artery
Vein	inferior mesenteric vein
Identifiers
Latin	arteria mesenterica inferior
MeSH	A07.231.114.565.510
TA	A12.2.12.069
FMA	14750
Anatomical terminology []

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 left colic (or splenic) flexure to the upper part of the rectum, which includes the descending colon, the sigmoid colon, and part of the rectum. 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.

The IMA branches off the anterior surface of the abdominal aorta below the renal artery branch points, and approximately midway between these and the aortic bifurcation (into the common iliac arteries), L3 vertebral level.

The IMA has the following branches:

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

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