There are several standard clinical tests for shoulder impingement. Your doctor probably conducted one or more of these tests on you to find the cause of the problem. Most of the time these tests are accurate enough that MRI, CT scans, or other imaging studies aren't needed.

The most definitive test is done by injecting a local anesthestic (like lidocaine) into the subacromial space. This is a space below the acromion, a curved piece of bone that comes over the shoulder blade, forming the highest point of the shoulder. The deltoid and trapezius muscles attach to the acromion.

Pain relief with testing after injection is a positive sign of impingement.