The sound of the bones in the arm is a common occurrence in daily life, and is caused by friction between the synovial membrane, ligaments and tendons in the joint when moving the arm. If the sound of bones is not accompanied by pain or discomfort, there is no need for special treatment and regular observation is sufficient; if the sound of bones is accompanied by pain, swelling and limited movement, it may be triggered by diseases such as osteoarthritis or localized bone ossification. The sound of bones may also be caused by a lack of calcium in the body, which may lead to the sound of bones.