Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Shoulder Injuries and Disorders ?
    ### Response:
    Your shoulder joint is composed of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone). Your shoulders are the most movable joints in your body. They can also be unstable because the ball of the upper arm is larger than the shoulder socket that holds it.
    