Injury

The acromio-clavicular joint, or ACJ, is located on the top of your shoulder. Injuries to this joint can lead to restricted and painful movement. If left untreated, postural changes and abnormal movement habits can occur, increasing the likelihood of secondary problems. The ACJ is formed by the end of your collar bone, or clavicle, and the acromion process; a bony bump at the top of your shoulder blade, or scapula.