Guide the patient to pronate. With the patient relaxed, place the flat hand across the posterior proximal forearm. Remind the patient, if needed, to keep the fingers and thumb relaxed. Guide the patient to extend and radially deviate the wrist. The extensor carpi radialis longus muscle should be the most prominently contracting muscle. Palpate other wrist extensor muscles to verify the palpation. From medial to lateral on the posterior proximal forearm, palpate the extensor carpi ulnaris with wrist extension and ulnar deviation motion, then the extensor digitorum communis with metacarpophalangeal extension of the four fingers, then the extensor carpi radialis brevis with pure wrist extension, fingers relaxed, then the extensor carpi radialis longus with wrist extension and radial deviation, fingers relaxed. In addition, the brachioradialis is located lateral to the extensor carpi radialis longus and is activated with resistance to elbow flexion with the forearm positioned in neutral pronation and supination. This sequence is viewed on the right video clip after palpation of the extensor carpi radialis longus muscle alone. With unclear muscle activity, increase the contraction of the extensor carpi radialis longus by asking the patient to hold the wrist in extension and radial deviation while you provide a push on the hand in the direction of flexion and ulnar deviation.