The ankle joint consists of the talus resting within the mortise created by the tibia and fibula as previously described. Since the talus is wider anteriorly (in the front) than posteriorly (at the back), as the front of the foot is raised (dorsiflexed) reducing the angle between the foot and lower leg to less than 90°, then the mortise is confronted with an increasingly wider talus. The force is heightened when the foot is simultaneously forced into external rotation (turned outward). This chain of events may occur when the front of a hockey player's skate strikes the boards and the foot is forced outward. It may also occur in football, for example, when a player is on the ground with their leg behind them, the foot at right angles, and a rotational force is suddenly applied to the heel, as when someone falls on their foot. Overall, the most common mechanism is external rotation and may occur with sufficient rapidity that the actual mechanism is unrecognized. In this sequence of events, the most vulnerable structure is the anterior inferior tibio-fibular ligament, uniting the lower end of the tibia and fibula and playing an important role in the maintenance of the mortise. The injury to this ligament may vary from simple stretch to complete rupture. Some restraint to further injury is offered by the structures on the inside of the ankle, the medial malleolus and the medial collateral ligament. However, should these structures fail, then the force will be transmitted beyond the anterior inferior tibiofibular ligament to the strong membrane that holds the tibia and fibula together for most of their length. This force may then exit through the upper end of the fibula, creating a so-called Maisonneuve fracture.
High ankle sprain
Humerus fracture
Medial knee injuries
Elbow fracture
Ankle fracture
Patella fracture
Sprained ankle
Back strain