The two clavicles are not the same height, which may be caused by the following reasons: 1. It may be caused by the patient’s own posture problem. For example, some patients over-adduct or internally rotate one side of the shoulder joint due to their own habits, or have a hunched back, at which point bilateral clavicle asymmetry may occur. This asymmetry will disappear if the patient’s shoulder joints are excessively abducted and externally rotated, and if they are asked to lift their chest and head. 2. It may be caused by old damage to the clavicle. If there is an old fracture of the clavicle on one side or an old sprain and contusion of the soft tissue around the clavicle, after recovery, there may be a shortening of the clavicle on one side or a localized bulge protruding from the skin surface. 3. There may be a congenital deformity. This condition is often seen when the patient has a family history or has suffered a birth injury during childbirth, resulting in bilateral asymmetry of the clavicle. 4. This condition may also be caused by prolonged pressure. If the patient lies on one side for a long time, it may cause shortening of the clavicle on that side and bilateral asymmetry.