Riolan's arcade

Marginal artery of the colon
Frontal view of the abdominal aorta and the territory supplied by the inferior mesenteric artery. The arteries on the right side (left side of image) arise from the superior mesenteric artery (SMA). The marginal artery (not labeled) connects the middle colic artery (a branch of the SMA) to the left colic artery (a branch of the IMA).
Colonic blood supply (Marginal artery is #9)
Details
Source	superior mesenteric artery, inferior mesenteric artery
Supplies	large intestine
Identifiers
Latin	arteria marginalis coli
Dorlands /Elsevier	a_61/12154972
TA	A12.2.12.068
FMA	14824
Anatomical terminology []

In human anatomy, the marginal artery of the colon, also known as the marginal artery of Drummond and artery of Drummond (named after Hamilton Drummond (1882 - 1925) a son of Dr|Sir David Drummond]] (1852-1932) an English physician), is a blood vessel that anastomoses (connects) the inferior mesenteric artery (IMA) with the superior mesenteric artery (SMA). It is sometimes absent, as an anatomical variant.

Along with branches of the internal iliac arteries , also known as Cherbanyk's arteries, it is usually sufficiently large to supply the oxygenated blood to the large intestine covered by the inferior mesenteric artery and is a reason that in abdominal aortic aneurysm repair the inferior mesenteric artery does not have to be re-implanted (re-attached) into the repaired abdominal aorta.

The Marginal Artery of Drummond runs in the mesentery close to the bowel as part of the vascular arcade that connects the SMA and IMA. This artery is almost always present and its absence should be considered a variant.

The Arc of Riolan (Riolan's arcade, Arch of Riolan, Haller's anastomosis), also known as the meandering mesenteric artery, is another vascular arcade present in the colonic mesentery that connect the proximal middle colic artery with a branch of the left colic artery. This artery is found low in the mesentery, near the root. In the setting of chronic ischemic colitis, both the marginal artery and the meandering mesenteric artery may be enlarged significantly, and may provide significant blood flow to the ischemic colonic segment.