Figure 10. (a) Lateral radiograph of the femur showing an ossified mass abutting the bone. A thick, predominantly single lamina of periosteal new bone extends proximally and distally (arrows). (b) Axial CT through the lesion shows that the ossification is in a peripheral location (zoning phenomenon), and has matured to form an outer cortex and inner medulla. There is a lucent space separating the lesion from the femur. Diagnosis: post-traumatic myositis ossificans.