Acute lateral ankle ligament injuries are often also referred to as ankle sprains. It is one of the most common injuries in orthopedic outpatient and emergency departments. According to statistics, ankle injuries account for 15% of all sports injuries, and 85% of these are lateral ligament injuries. In acute injuries, the ankle joint has a history of inversion sprain, and some patients can hear or feel the sound of tissue tearing at the time of injury. Some patients are able to continue to walk with weight after the injury. 24-48 hours after the injury, there may be bruising and ecchymosis under the skin of the lateral ankle joint due to the absorption and decomposition of the hematoma. On examination, swelling of the anterolateral aspect of the ankle joint can be seen. Early in the injury, when the swelling is not severe, a careful search for pressure points can help determine the exact site of the ligament injury. Anterior talofibular ligament injuries often have pressure points at the fibular attachment point, while heel-fibular ligament ruptures often have pressure points at the heel attachment point. When the ligament is completely ruptured, the ligament rupture gap can sometimes be palpated. However, if it has been several hours since the injury and the swelling is heavy, the pressure point is not clear. When the forefoot is passively inwardly retracted and the ankle is turned inwardly, the local pain can be increased. After complete rupture of this ligament, the talus may become unstable in the anterior-posterior direction. According to the patient’s performance after the injury, the lateral ligament injury is divided into mild, moderate and severe degrees: 1. Mild degree: the function of the ankle joint is mildly affected. There is no claudication, no or mild swelling. There are limited pressure points, which can cause pain when the trauma mechanism is repeated. 2.Moderate: Ankle function is moderately affected. Walking limp, ankle cannot be actively dorsiflexed, localized swelling and pressure pain. 3.Severe: extensive swelling and pressure pain. Whether acute injury or chronic instability, examination of stability is very important. In clinical practice, anterior drawer test and talar tilt test are often required to help determine whether the ankle joint is stable.