The sternoclavicular joint occurs between the proximal end of the clavicle and the clavicular notch of the manubrium of the sternum together with a small part of the first costal cartilage. The sternoclavicular joint is a saddle-type joint that allows movement of the clavicle, predominantly in anteroposterior and vertical planes, although some rotation also occurs. The ability to thrust the arm and shoulder forward requires sound function of this joint.
Usually only through significant force do the ligaments supporting the sternoclavicular joint become completely disrupted, enabling dislocation of the joint. The extent of the damage to the supporting ligaments and capsule dictates whether the joint subluxes or dislocates. Sternoclavicular joint injuries are graded into three categories.