Gerber's Lift-Off Sign tests the integrity of which muscle?

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

Answer: (A)

Gerber's lift-off sign directly assesses the subscapularis because it requires the muscle to contract to internally rotate the shoulder while the hand is placed behind the back. In the test, the patient places the back of the hand on the lower back and attempts to lift the hand away from the back against the examiner’s resistance. The subscapularis is the primary internal rotator and a key stabilizer of the humeral head, so a normal subscapularis can perform this lift-off and hold the position against pressure. If the subscapularis is torn or weak, the patient can’t initiate or maintain the lift-off, producing a positive sign. The other rotator cuff muscles are mainly involved in external rotation or initial abduction, which this maneuver does not primarily test, so their dysfunction wouldn’t yield the same result.