Superior mesenteric artery

The superior mesenteric artery is a large artery that supplies the whole length of the small intestine, except the superior part of the duodenum; it also supplies the caecum and the ascending part of the colon and about one-half of the transverse part of the colon.

The superior mesenteric artery arises from the front of the aorta, about 1.25 cm. below the celiac trunk, and is crossed at its origin by the splenic vein and the neck of the pancreas.

The superior mesenteric artery passes downward and forward, anterior to the processus uncinatus of the head of the pancreas and inferior part of the duodenum, and descends between the layers of the mesentery to the right iliac fossa, where, considerably diminished in size, it anastomoses with one of its own branches, the ileocolic artery.

In its course, the superior mesenteric artery crosses in front of the inferior vena cava, the right ureter and psoas major, and forms an arch, the convexity of which is directed foward and downward to the left side, the concavity backward and upward to the right. It is accompanied by the superior mesenteric vein, which lies to its right side, and it is surrounded by the superior mesenteric plexus of nerves.