The shoulder is a very complex joint and can sometimes be very difficult to find the specific cause of pain.
The shoulder joint allows a large amount of movement due to it being a ball and socket joint. This means that it does not have a lot of surface area to support bone on bone contact so it relies heavily on static structures (ligaments, glenoid labrum) and dynamic structures (muscles) to stabilise the ball in the socket.
The shoulder is also complex as it does not just have one joint, it is a combination of 4 joints with the arm bone moving in rhythm with the shoulder blade, collar bone and upper back. This is important to recognise as injury, weakness or tightness can often occur in one or all of these joints. The movement of the shoulder blade (scapula) and the arm (humerus) is called scapulohumeral rhythm. In order to have efficient shoulder movement muscles need to be either tensing or relaxing to facilitate 3D movement of the shoulder blade. If this movement is not smooth and muscles are out of sync with each other then it can cause subacromial impingement.
Subacromial impingement is when the space between the arm and the shoulder blade narrows. This decrease in space can cause the bone to press on the tendon of the rotator cuff, bicep tendon or the bursa (a fluid filled sac to prevent excessive rubbing between bone and tendon) and can cause significant pain when lifting the arm above 90 degrees.
To address this shoulder pain, a physiotherapist will observe the posture and movement to analyse how the shoulder blade is resting and moving in relation to the ribcage and the arm. The ribcage and upper back can play a big role in shoulder pain because the shoulder blade has to sit against the rib cage. Therefore, if the upper back movement is limited it can affect the movement of the shoulder blade and cause impingement symptoms.
Manual therapy combined with exercise rehabilitation is the best approach
Manual techniques to reduce the tension in tight muscles and specific exercises to improve the movement of the shoulder blade and arm also yield positive results. Once pain free range of movement has been restored, then a strengthening program will be needed to gradually increase the load on muscles and tendon of the shoulder to improve the efficiency and overall function of the shoulder.
Two exercises to address the upper back stiffness to improve shoulder blade mechanics are: