The Lateral Ankle

By Ben Benjamin, PhD

Question: Does the ankle have one, two or three lateral collateral ligaments?

Answer: The ankle has three lateral collateral ligaments: the anterior talo-fibular ligament, the calcaneo-fibular ligament and the posterior talo-fibular ligament (also known as the posterior lateral ligament).

Question: Why is the lateral aspect of the ankle more prone to injury than the medial ankle?

Answer: Don't try it, but it's a lot easier to fall over on your ankle laterally than to fall medially.

But why is that so? The ligaments of the ankle hold the foot and the lower leg together. These ligaments, which consist of the three lateral collateral ligaments named above and the deltoid ligaments at the medial ankle between the lower tibia and the bones of the foot, are the stabilizing structures of the ankle joint.

There is more movement at the lateral side of the ankle than at the medial side of the ankle, because there is more play in the lateral ligaments of the ankle. The bone structure of the ankle is also configured to allow more movement in supination than in pronation. The principle to keep in mind is that with more movement comes more vulnerability to injury; therefore the lateral ankle ligaments are more prone to injury than the medial ligaments.

When the peroneal tendons (A and B) are torn, you feel pain at 1, 2, 3.Question: Which ankle ligament is the most commonly injured?

Answer: The anterior talo-fibular ligament.

When treating a lateral ankle sprain, it is important to identify which of the three ligaments is injured, so that the appropriate treatment can be applied. In more serious sprains, all three ligaments are often injured. After the swelling is gone and the person can walk normally again, there is sometimes an unexplained pain just behind the lateral ankle bone. Injury to the peroneal tendons, which pass behind the lateral malleolus, is often the cause of this residual pain.