The SC joint is one of the 4 joints of the shoulder. It is formed by your clavicle (collar bone) and sternum. This joint is located on the front of your chest.  There is only a small amount of movement that occurs here when the shoulder blade moves. This joint is usually fairly stable due to the strong ligaments but injury is possible following trauma or collar bone fracture. Your therapist will be able to assess this joint and create a care plan to restore your function.