Abnormal scapula morphology Scapulothoracic incongruity 2026-02-24T07:47:23Z Snapping scapula syndrome, washboard syndrome, or scapulothoracic crepitobursitis are clinical manifestations of scapulothoracic incongruity usually associated with painful crepitus and shoulder joint dysfunction when attempting overhead motion. A lack of smooth, physiological alignment or movement between the scapula (shoulder blade) and the posterior thoracic wall (the rib cage). The scapulothoracic joint is unique, as it lacks true synovial articulation and is dynamically controlled through surrounding muscular contractions. The scapula glides on the posterior thorax covered with muscle layers rather than a cartilaginous surface. This feature can be ascertained by radiography or CT scan of the scapula showing incongruity of the scapulothoracic space.