Imaging the child with a limp.

A great many pathologic conditions can cause a child to limp. Prior to imaging, it is necessary to complete a thorough history and physical examination in order to limit the differential diagnosis to a few possible causes. The selection of imaging modalities should then be guided by the history and physical examination findings. Because of their sensitivity and specificity for detecting a wide range of bone pathology, radiographs should be obtained first. Plain radiographs often are diagnostic. The choice of sonography, CT, bone scintigraphy, or MR imaging is made while keeping in mind the strengths of each imaging modality.