Shoulder impingement is a common cause of shoulder pain. Before jumping into the specifics of what “shoulder impingement” means, it is important to understand the anatomy of the shoulder.
Shoulders are inherently unstable joints. The head of your humerus sitting on your glenoid is much like a golf ball sitting on a tee. This instability actually benefits us as humans because it translates to having a lot of freedom of movement, more than any other joint in our bodies. Without that extra movement we would not be able to swim, throw, reach behind our backs, etc.
Description and causes of shoulder impingement
As you raise your arm overhead or out to the side, the subacromial space narrows. This can cause pinching or “impingement” of the tendons or bursa that live in the subacromial space. The majority of the time, our bodies can tolerate this pinching and loading. However, there are some situations when it is more than those structures can tolerate:
Shoulder impingement most often causes pain and tenderness in the front of the shoulder. This pain may also extend down the front and side of the arm. It is particularly painful with lifting the arm forward and out to the side. It may also be painful with lowering arm from a lifted position. It may be difficult or painful to sleep on the shoulder. People also describe feeling that the painful arm is weak and that motion is limited.
Treatment often is focused on protected the irritated tissues. It is also important to strengthen upper back musculature, which helps improve upright posture. This opens up the subacromial space and decreases pinching in that area. As the irritated rotator cuff muscles become less painful, rehab usually includes strengthening those muscles to increase the amount of load they are able to tolerate moving forward.
If you believe you may be experiencing shoulder impingement, a PT can further evaluate you and personalize a rehabilitation program!
Bob Cranny, PT