Snapping scapula, also sometimes called scapulothoracic crepitus or scapular crepitus, is characterized by a painful cracking or snapping in the shoulder blade. The disorder can occur as a result of poor posture, shoulder trauma or surgery, and can be treated either by physical therapy or more aggressively through surgical procedure.The characteristic involuntary “snapping” of the shoulder blade of snapping scapula is believed to result from improper motion of the shoulder blade against the rib cage and thoracic (upper) vertebrae. There is some dispute regarding whether snapping scapula results simply from specific behaviors and events, or whether an actual pre-existing physical abnormality may produce the condition.
Specific behaviors and events that can result in snapping scapula are poor posture, misalignment of the shoulder blade from trauma, surgery or other incident. In general, abnormal movement of the shoulder blade causes an improper drag or catch on the rib cage, creating friction and the characteristic snap. For individuals with poor posture, this problem is the result of a drooping scapula, which enhances contact with the rib cage. The same effect can result from trauma to the shoulder or surgery in which back muscles or other support structures are injured.
Additionally, there is increasing evidence that pre-existing microscopic bony projections or rough areas at the edge of the scapula may also be responsible for incidence of snapping scapula. Such skeletal or soft-tissue abnormalities were often missed using older imaging systems, but new technologies, such as three-dimensional computed tomography, have recently identified this additional origin of impairment. Yet another source for the pain accompanying this condition is the possible inflammation of the bursae, or sack of viscous fluid, that sits between the scapula and adjacent thorax.
