Superior mesenteric artery syndrome.

Superior mesenteric artery syndrome is a rare and controversial form of upper intestinal obstruction in which the third part of the duodenum is compressed by the overlying superior mesenteric artery. Any disease process decreasing the angle between the superior mesenteric artery and the abdominal aorta can result in the external compression of the duodenum and subsequent intestinal obstruction. The aetiology, presentation, investigation and management of this unusual condition are discussed.