Radiographic measurements of the ankle for syndesmotic injury

The diagram above shows several important anatomic relationships of the ankle that are used to help diagnose syndesmotic injury. The medial clear space (MCS) is the distance between the medial border of the talus (point E) and the lateral border of the medial malleolus (point F) measured 5 mm below the talar dome. The tibiofibular clear space (TFCS) is the distance between the posterolateral tibia (point D) - sometimes called the incisura fibularis - and the medial fibula (point C) measured 10 mm above the tibial articular surface.