A retrospective study was made of patients with initially negative radiographs and positive radionuclide bone images. Comparison of conventional radiography and bone scanning in traumatology shows that the masked bone fracture can be seen in the bone scan but a focal accumulation of the radioactive material may not correspond to a bone fracture in every case. The ligamentous avulsion of a bone chip and/or the periosteum can yield the same image. Usually bones respond to trauma with an abnormal focal tracer accumulation because of irregular metabolic processes and the disturbance of the local blood circulation. By using a highly sophisticated technique (3-phases bone scanning) the focal disturbances can be seen. The greatest problem in scanning is the nonspecificity of abnormal tracer accumulation. Although bone scanning is very important in the diagnosis of any traumatic lesion of the bone it cannot replace the conventional radiograph.