Drop Arm Test is most specific for pathology of which rotator cuff muscle?

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

Answer: (C)

Drop Arm Test targets the supraspinatus because this muscle initiates the first phase of shoulder abduction and provides eccentric control as the arm is lowered from an elevated position. When the supraspinatus is torn or significantly fatigued, a patient cannot smoothly control or slowly lower the arm from about 90 degrees of abduction; the arm drops abruptly, sometimes with pain. This pattern is highly specific to supraspinatus pathology, so a positive test strongly points to that muscle. Other rotator cuff muscles contribute to different movements—the infraspinatus mainly to external rotation, the subscapularis to internal rotation (lift-off/belly-press tests), and the teres minor to external rotation as well—so they don’t produce the same distinct dropping sign on this test.