What might a positive Drop Arm Test indicate?

A positive Drop Arm Test is indicative of a rotator cuff tear, specifically involving the supraspinatus muscle or tendon. This test assesses the integrity of the rotator cuff by having the patient abduct their arm to shoulder level and then lower it slowly. If the arm drops or falls uncontrollably, it suggests a loss of strength or control in the rotator cuff, which is a common occurrence with a tear.

The test's effectiveness lies in its focus on the rotator cuff's ability to stabilize the shoulder joint during abduction. A rotator cuff tear can compromise this stabilization, leading to an inability to maintain the arm's position.

In contrast, shoulder separation typically involves the acromioclavicular joint rather than the rotator cuff structures, and does not typically result in a positive Drop Arm Test. Tendinitis may present with pain and discomfort but does not usually produce the same drop response as a full tear. A fracture of the humerus could also lead to symptoms that impair arm movement, but the specific mechanism tested by the Drop Arm Test is more closely associated with rotator cuff integrity than with bone fractures.