Like a swivelling seat for a gunnery shooter, the scapular must move to provide a base or platform of movement for the arm. This means that wherever the arm moves to, the scapula must move correspondingly to enable a platform or base against which to push. As the arm (humerus) is able to move so widely in such a wide arc of motion, the scapula must be able to move and rotate in a corresponding fashion providing adequate support and enabling efficient, functional biodynamics.
Shoulder injuries are amongst the most notorious and debilitating of beasts. They are amongst the most popular of issues presented to me in my working life and I will admit, one’s that will result in people giving you a random hug in a coffee shop months later when they remember that you helped fix their shoulder (TRUE). It’s not that the shoulder is the most painful of injuries or the most drastically impactive, but it is very much the most difficult one to get right. Due to it’s anatomy, it only responds to diligent treatment and adherence to treatment protocols. In other words – it’s a team approach (more homework for you).