The Empty Can Test, along with the Full Can Test is a commonly used orthopedic examination test for supraspinatus impingement or integrity of the supraspinatus muscle and tendon. The test is also sometimes called the Empty Beer Can Test.
The test is usually easier in sitting or standing. On the side to be tested, one of the examiner's hands stabilizes shoulder girdle. The arm to be tested is moved into 90 degrees of forward flexion in the plane of the scapula (approximately 30 degrees of abduction), full internal rotation with the thumb pointing down as if emptying a beverage can.
The Empty Can Test is considered positive if there is significant pain and/or weakness. Pain alone is less accurate than actual weakness, especially when the arm is tested in full can position (45degrees of external rotation) as pain can be the result of supraspinatus tendonitis or other injured or inflamed structures. Weakness can be the result of a tear in the supraspinatus muscle or tendon but can also be the result of pain induced inhibition. Pain is usually felt in the subacromial region but can sometimes be felt into the upper arm.
The test accuracy is questionable; pain may be a result of multiple different structures and may not be indicative of actual muscle or tendon tear. The test is more accurate for detecting a tear in the muscle or tendon if very significant weakness is present.