This joint is very mobile with almost 3D movement and held in place by muscles, rather than a solid joint of bone fitting into bone.
Aside from an impact of wrenching injury, many things in day to day life are affecting shoulder stability
- Using a mouse at the computer
- Leaning on the car window
- Carrying a bag on one shoulder
- Asymmetric sports such as tennis/golf
What these do is allow the shoulder to drop forwards and the scapular wings and hangs away from the rib cage causing pain between the shoulder blades and neck.
The shoulder blade swings flush against the rib cage, so if posture is poor then the shoulder will be compromised in function.
Strapping can help to relieve discomfort and remind the patient where the shoulder should sit, however it is an unrealistic long term option, the best solution is changing habits and corrective work.