Ligament · Ankle

Posterior talofibular ligament

Ligamentum talofibulare posterius

The strongest and deepest of the three ligaments on the outer ankle, running almost horizontally backwards from the pit on the inner face of the lateral malleolus to the back of the talus. Its fibres are short, thick, and sit close to the axis the ankle turns on, so it stays slack through most of normal movement and tightens only when the foot is pulled fully upward and outward. That is the mirror image of its neighbour the anterior talofibular ligament, which is taut when the foot points down — the two take turns depending on where the ankle sits. Being both strong and slack through the range the ankle actually works in, it is the least loaded of the three.