The ankle is the joint between the foot and the lower leg, mainly consisting of the distal end of the tibia and the distal end of the fibula of the lower leg together with the talus of the foot. It is surrounded by ligaments and joint capsule to stabilize the ankle joint. The medial ligament is called the deltoid ligament, the lateral ligament is called the lateral collateral ligament, the anterior side is mainly the anterior talofibular ligament, the posterior side is the posterior talofibular ligament, and the middle part is the heel-fibular ligament. Especially after a foot sprain, it is easy to cause damage to the ligamentous joint capsule of the ankle, thus causing significant swelling, pain and bruising in the ankle, and a serious sprain may also lead to fracture of the inner or outer ankle.