Technique: Extend your arm straight outwards and bend it at a 90 degree angle Point your fingers upwards and your thumb to one side Pull your thumb down with your other hand   Primary muscles: Flexor pollicis longus. Flexor pollicis brevis. Secondary muscles: Adductor pollicis. Opponens pollicis.   Injury where stretch may be useful: Tennis elbow. Golfer’s elbow. Thrower’s elbow. Wrist sprain. Wrist dislocation. Wrist tendonitis. Carpal tunnel syndrome. Ulnar tunnel syndrome. Note: There are many small muscles, tendons and ligaments in the palm and thumb. Do not apply too much force too quickly.        ...