Comminuted fracture of the fibula with butterfly fragment on radiography

The frontal radiograph of the left fibula (A) shows a comminuted spiral fracture of the distal shaft. Image B shows the fracture outlined with black overlay, while image C reveals three fragments with the lightest turquoise green overlaying the triangular or butterfly fragment. The mechanism of this injury is usually a twisting or torsional injury (thick arrow). The interosseous membrane acts as a resisting force (thin arrows)accounting for the butterfly fragment.