My doctor told me that I have shoulder “impingement”. What does that mean?
Both athletes and the general population can develop shoulder discomfort or pain, particularly if they perform repetitive overhead motions. If you are throwing a baseball, swimming the butterfly, or painting a wall, repeated overhead motions can become very painful if your rotator cuff is not functioning properly.
Shoulder impingement is one of the most common causes of pain in the shoulder. It results from the rotator cuff being pinched between the humerus and the scapula. The rotator cuff is made up of four muscles: the supraspinatus, the infraspinatus, the teres minor, and the subscapularis. The job of this quartet of muscles, is to depress the shoulder joint when performing overhead activities. The acromion is the front of the scapula or shoulder blade. It sits just above the humeral head and rotator cuff tendons. When the rotator cuff is insufficient, the acromion (bony prominence at the top of the shoulder blade), rubs or “impinges” on the tendons when the arm is lifted overhead, causing pain and inflammation.
There are three main risk factors for developing shoulder impingement. First is anatomy. If you have a Type III or “hooked” acromion, you are more predisposed to shoulder impingement. Secondly, weakness in your posterior cuff (infraspinatus/teres minor) can cause abnormal shoulder mechanics leading to impingement. Lastly, tightness or decreased range of motion (particularly, internal rotation) may increase your risk of shoulder impingement. Recent studies suggest that athletes with a 20% deficit in internal rotation (range of motion) in the dominant shoulder are more likely to experience a rotator cuff injury.
Melissa Prestipino, DPT
Sparta Fit For Life - Therapeutics Unlimited Rehab