What is the primary cause of shoulder impingement syndrome?

The primary cause of shoulder impingement syndrome is compression of the rotator cuff tendons under the acromion. In this condition, anatomical structures within the shoulder joint, specifically the rotator cuff tendons, become irritated and inflamed as they pass beneath the acromion, which is a bony projection on the scapula. When the arm is lifted, these tendons can get pinched against the acromion, leading to pain and dysfunction.

This impingement can result from various factors, such as repetitive overhead activities, variations in shoulder anatomy, or previous injuries that may lead to inflammation or swelling. Understanding that this is the primary mechanism helps in developing appropriate treatment strategies, which may include physical therapy, activity modification, or anti-inflammatory measures to alleviate the symptoms and restore shoulder function.