A bag bulging above the ankle is commonly caused by trauma, tendon sheath cyst and so on, as follows: First, local trauma: such as fracture, muscle tendon strain, can cause local bleeding, and then the formation of hematoma, manifested as local bruising, and the formation of lumps, relatively soft texture and painful symptoms when pressed, can be diagnosed through ultrasound examination, need to be punctured to extract the hematoma. If the hematoma has become mechanized, it needs to be absorbed by itself or removed by incision. Secondly, tendon sheath cyst: long time sports and repeated activities of ankle joint will cause serious wear and tear of local tendons and tendon sheaths, degenerative changes will occur and tendon sheath cysts will be formed, the texture of local pressure is soft and painful, ultrasound examination can find the cyst wall and cyst fluid, all need to consider surgical treatment to remove the cysts.