Low collarbone and high collarbone may be caused by shortening of one side of the collarbone, dislocation of the acromioclavicular joint, scoliosis and other factors. 1. Shortening of one side of the clavicle: one side of the clavicle is born with abnormal development or lying on the side for a long time, which may shorten one side of the clavicle and lead to one side of the clavicle being low and the other side being high. 2. Dislocation of acromioclavicular joint: Acute injury to the shoulder joint may be complicated by dislocation of acromioclavicular joint, which is not treated in time and cannot be healed completely, resulting in the two sides of the clavicle not being the same height, which may be accompanied by pain and swelling and other symptoms. 3. Scoliosis: For example, bony scoliosis or postural scoliosis may lead to uneven and asymmetric shoulder joints on both sides, and the clavicles may be high on one side and low on the other. If the clavicle is low on one side and high on the other, and it is more obvious, you should consult the doctor in time, and according to the results of the examination and diagnosis, you will be treated accordingly.