Spiral fracture of the femur in a non-mobile infant is always worrying for non-accidental injury (child abuse). Radiographic skeletal survey was performed in this case but no other injury was seen. Bone scan however revealed focal increased uptake in the right 4th to 7th ribs posteriorly consistent with fracture. This is the most common site of non-accidental rib fracture in infants due to a compressive squeezing force applied to the chest.
The lack of tracer uptake around the right femur fracture does not necessarily mean the fractures happened at different times as the degree of displacement of the femoral fracture may have prevented osteoblastic activity.