1. Five cases are reported in which snapping of the scapula was caused by subscapular exostosis. In the four cases in which the exostosis was excised, symptoms were relieved without loss of scapular movement.

2. Antero-posterior views of the scapula do not always show the exostosis, and oblique views are recommended.

3. Winging of the scapula may be caused by a subscapular mass, with a neurologically intact subscapularis muscle.

4. Apart from subscapular exostoses, snapping of the scapula may be caused by exostoses or abnormal angles on the ribs, by Luschka's tubercle, or by an abnormal forward curve of the superior angle of the scapula.