This is a very common instability where the inside edge of the shoulder blade is not connected with the upper back. Isolating arm and shoulder movement can be a challenge for this group. The ‘winging’ position of the scapula on the upper back, has a knock on effect at the glenohumeral (shoulder) joint, pushing it forwards.
The muscular biomechanics have shifted, muscles at the front of the chest have shortened and are potentially pulling the front of the shoulder forwards. The bigger stronger muscles of the back, latissimus and lower traps, have weakened and become long.
Combined this presenting picture may lead to poor mobility and pain in the neck and shoulder, wide open (literally) for injury. Re-positioning is effective, using all kinds of tools, tape, scapula resetting, somatic and pilates based stability exercises. Retraining the breath can have huge positive results here. Check out my tutorial on pulleys for a 4 minute fix.
Wild Atlantic Physio 