To strengthen the muscles whose function is to rotate the upper back, and to increase mobility in the joints of the thoracic spine.
Attach one end of an elastic exercise band securely to a strong structure, for example, the handle of a closed door. Hold the other end of the band in the hand of the affected side and stand with your back to the secured end so that the slack is taken up with the hand resting by your side.
Slowly and in a controlled manner, bring your arm straight out in front of you and across your body, driving your upper back into rotation. At end of range, pause, then slowly return to the starting position.
As your rehabilitation progresses your osteopath may advise you to increase both the number of repetitions and the strength of the exercise band.