Superior mesenteric artery

Dr Craig Hacking ◉ and Dr Donna D'Souza ◉ et al.

The superior mesenteric artery (SMA) is one of the three non-paired arteries that provide blood to the midgut and other abdominal viscera.

Courses anteroinferiorly, behind the neck of pancreas and splenic vein, crossing anterior to the left renal vein. It emerges anterior to the uncinate process of the pancreas and crosses anterior to the third part of duodenum. It then enters the upper portion of the small bowel mesentery and runs along the root of the mesentery downwards to the right. Branches to the jejunum and ileum are given off to the left, and branches to the proximal and mid colon are given off to the right.

The SMA terminates at the ileum where it anastomoses with the ileal branch of the ileocolic artery. Some anatomists believe the ileocolic artery is the terminal portion of the SMA and that what many consider the terminal SMA is the last of the ileal branches.

The superior mesenteric vein (SMV) should always lie to the right of the SMA, otherwise malrotation should be suspected.

Branches

inferior pancreaticoduodenal artery

Left-sided

Right-sided

Marginal artery of Drummond

The terminal branches of the ileocolic, right colic and middle colic arteries - along with the terminal branches of the left colic artery and sigmoid branches of the IMA - form a continuous arterial circle or arcade along the inner border of the colon known as the marginal artery of Drummond. From this marginal artery, straight vessels (also known as vasa recta) pass to the colon.

Supply

The SMA is the artery to the midgut. It supplies the gut from the ampullary region of the 2^nd part of the duodenum to the splenic flexure. The inferior pancreaticoduodenal artery also supplies the head of the pancreas.