The role of the subscapularis in preventing anterior glenohumeral subluxation in the abducted, externally rotated position of the arm

Exercises alone are unlikely to be adequate for all patients with anterior instability symptoms. Passive motion pattern of the humeral head might serve as an indicator as to whether the effect of strengthening the subscapularis might stabilize a shoulder without further operation. Development of a clinical test based on these findings might differentiate the non-operative from operative candidates among patients presenting with anterior instability of the shoulder.