What is the most common cause of shoulder impingement syndrome?

Shoulder impingement syndrome is primarily caused by the entrapment of the rotator cuff tendons and surrounding tissues beneath the acromion, especially during overhead activities. Subacromial bursitis, which refers to inflammation of the subacromial bursa, is a key contributor to this syndrome. When the bursa becomes inflamed, it can lead to pain and reduced range of motion as it gets compressed during arm movements. This condition often occurs in tandem with other issues, but inflammation of the subacromial bursa is recognized as a central factor that exacerbates the impingement.

While rotator cuff tears, shoulder instability, and osteoarthritis are valid pathologies that can lead to shoulder problems, they are typically not the primary cause of impingement syndrome itself. Impingement is more frequently linked to the anatomical and functional changes at the subacromial space that can occur over time or due to repetitive overhead motions, making subacromial bursitis the most common cause in many cases.