What are the ligaments of the ankle?
The ankle is a hinge joint between the leg and the foot, and allows up and down movement. The bones of the leg (tibia and fibula) form a slot, and the talus bone of the foot fits between them. The talus is held to the tibia and fibula by strong bands of tissue called ligaments. Each ligament is made of many strands or fibres of a material called collagen, which is extremely strong.
The ligament on the inside of the ankle (the deltoid ligament) has two layers; the deepest one is most important. This ligament is mainly torn in association with severe fractures of the ankle bones. Sporting injuries of this ligament are rare.
The ligament on the outside of the ankle (lateral ligament) is made up of three separate bands: one at the front (anterior talo-fibular ligament), one in the middle (calcaneo-fibular ligament) and one at the back (posterior talo-fibular ligament). The front and middle bands are the ligaments injured in a sprain.
The tibia and fibula form a joint between themselves just above the ankle. This also has strong ligaments, one at the front and one at the back (tibio-fibular ligaments). The ligament at the front is involved in 10-20% of ankle sprains; this injury is important, as it takes a long time to heal, although it usually heals without the need for surgical treatment.