Painful arc (impingement) syndrome
The rotator cuff is a group of four muscles and their tendons. It controls movement and also helps to hold your shoulder joint together. When rotator cuff tendons become inflamed or worn, it causes a painful arc or 'impingement' syndrome.
Doctors may use different terms to describe the same condition, such as supraspinatus tendinitis or subacromial bursitis.
If you have a painful arc you'll usually feel pain as you lift your arm away from your body. This may happen because there isn’t enough space for the tendons to pass freely.
Treatment for painful arc is mainly with physiotherapy. Sometimes a steroid injection, combined with a local anaesthetic, into the space below the acromion can help with the pain. But if the pain doesn’t settle, or comes back within a few months, you may need keyhole surgery.