Pain of musculoskeletal origin in children.

Pain in infants and children may be manifest by deformity, altered function, or discomfort. These manifestations are highly age related. Pseudoparalysis may be the only manifestation of septic arthritis of the hip in the neonate; a limp is often the presenting complaint in Perthes' disease, and scoliosis may be the primary manifestation of a herniated disc in an adolescent. New imaging methods aid in diagnosis. Ultrasound is helpful in assessing joint effusions; bone scans localize the cause of a limp; and magnetic resonance imaging shows spinal cord and root lesions. The traditional methods of assessment have not been replaced. History and physical examination are most essential to provide a rational basis on which to select the appropriate imaging study.