Ankle sprains are classified based on the severity of the injury. They are given a grade of 1, 2 or 3.
Grade 1 sprains have slight stretching and some damage to the fibers of the ligament.
Grade 2 sprains have partial tearing of the ligament. If the ankle joint is examined and moved in certain ways, abnormal looseness of the ankle joint is found.
Grade 3 sprains have a complete tear of the ligament. If the provider pulls or pushes on the ankle joint in certain movements, gross instability occurs.