Drop Arm Test evaluates pathology of which rotator cuff muscle?

• A. Infraspinatus
• B. Supraspinatus
• C. Subscapularis
• D. Teres Minor

Answer: (B)

The Drop Arm Test targets the supraspinatus. This muscle starts the arm's elevation from about 0 to 90 degrees of abduction and helps control the movement eccentrically as the deltoid takes over. If the supraspinatus tendon is torn or significantly damaged, a patient cannot maintain that 90-degree position when slowly lowering the arm; the arm tends to drop abruptly or with pain. That inability to control the descent is what makes the test positive for supraspinatus pathology.

Other rotator cuff muscles are tested with different maneuvers: infraspinatus is evaluated by resisted external rotation, subscapularis by lift-off or related internal-rotation tests, and teres minor involvement is assessed through external rotation with various arm positions. Those tests focus on the specific actions of those muscles rather than the controlled lowering from a raised position, which is why the Drop Arm Test is best for supraspinatus pathology.