Shoulder pain is a common complaint among baseball pitchers. Frequently, the nature of shoulder pathology can be traced to lack of flexibility and muscular imbalance. This paper describes: the normal biomechanics of a properly functioning shoulder during a baseball pitch, pathomechanics of shoulder problems, flexibility requirements of the throwing shoulder, and the muscular balance necessary for an effective throwing shoulder. Appropriate examination procedures are described along with remedial exercises which ensure normal glenohumeral motion and integrated muscle action.