Rotator cuff tendonitis is irritation of the tendons that center the ball in the socket during every arm movement. The modern understanding is less about pure inflammation and more about load imbalance: tendon asked to do more than its current capacity - a spike in overhead work, training, or lifting - degrades faster than it repairs, and pain follows. That is why the signature complaints are position-based: a painful arc as the arm passes shoulder height, ache reaching behind the back or into a jacket sleeve, and night pain lying on the affected side.
One variant deserves its own name: calcific tendonitis, where calcium deposits form within the tendon and can trigger episodes of abrupt, severe pain. It shows on plain X-rays and is managed differently, which is one reason imaging earns its place when symptoms are atypical or intense. Untreated cuff overload can progress along a spectrum toward partial or full-thickness rotator cuff tears, so persistent symptoms deserve a diagnosis rather than repeated rest cycles.
What is rotator cuff tendonitis?
Rotator cuff tendonitis is inflammation of the rotator cuff tendons (supraspinatus, infraspinatus, teres minor, subscapularis) without tearing. It results from repetitive overhead activities, impingement, poor posture, or age-related degeneration. It's a precursor to rotator cuff tears.
