Definition
Ankle sprain is the result of stretching and/or tearing of ligaments that join the ankle bones together. They are usually an acute injury with the lateral (outside) ligament more commonly injured than the medial (inside) ligament.
The mechanism of injury usually involves landing on a foot that is pointing downwards and inwards (plantarflexed and inverted), causing damage to the lateral ligaments (ATFL). This usually occurs when running on uneven terrain, stepping in a hole, stepping on another person’s foot when landing from a jump in an unbalanced position. Occasionally but less commonly, the foot can twist outwards damaging the medial ligaments.
The extent of the damage depends on the direction and amount of forces applied to the foot and the position of the foot and ankle during the incident. Ankle injuries are usually classified as Grade 1 (mild), Grade 2 (moderate) and Grade 3 (severe).
