Wide mortise associated with tibiofibular syndesmosis tear

This anteroposterior radiograph of the ankle shows widening of the ankle mortise. Note the increased space between the medial malleolus and the adjacent talus (also called wide medial clear space). This appearance strongly suggests a tear of the distal tibiofibular syndesmosis, an injury that is referred to as a syndesmotic sprain or, in layman's terms, a high ankle sprain.