Superior mesenteric Artery

In human anatomy, the superior mesenteric artery (SMA) is an artery which arises from the anterior surface of the abdominal aorta, just inferior to the origin of the celiac trunk, and supplies blood to the intestine from the lower part of the duodenum through two-thirds of the transverse colon, as well as the pancreas.

• It arises anterior to lower border of vertebra L1 in an adult. It is usually 1 cm lower than the celiac trunk. It initially travels in an anterior/inferior direction, passing behind/under the neck of the pancreas and the splenic vein. Located under this portion of the superior mesenteric artery, between it and the aorta, are the following:

• left renal vein - travels between the left kidney and the inferior vena cava (can be compressed between the SMA and the abdominal aorta at this location, leading to nutcracker syndrome).
• the third part of the duodenum, a segment of the small intestines (can be compressed by the SMA at this location, leading to superior mesenteric artery syndrome).
• uncinate process of pancreas - this is a small part of the pancreas that hooks around the SMA.
• The SMA typically runs to the left of the similarly named vein, the superior mesenteric vein. After passing the neck of the pancreas it starts giving off its branches.