Motility disorders of the small intestine: new insights into old problems.

Motility of the gastrointestinal tract is responsible for the orderly movement of food, in an oral-to-aboral direction, and allows for the digestion and absorption of nutrients and water, and the elimination of indigestible material. This complex series of events results from the integrated activity of enteric nerves, extrinsic nerves, the intrinsic properties of smooth muscle, and gastrointestinal hormones. Abnormalities in any of these components or in their integration can result in dysmotility: increased transit, decreased transit, or nonpropulsive activity. This review outlines the current understanding of the causes, pathophysiology, diagnostic evaluation, and treatment of motility disorders of the small intestine.