Isometric ring finger abduction (4th dorsal interosseous)

Sit upright in a chair.
Place your affected arm on a table with your palm facing down and your fingers flat.
Place your index finger from your unaffected hand on the little finger side of your ring finger.
Try to move your ring finger towards your little finger, using your opposite hand to resist the movement.
Keep your palm and forearm flat on the table throughout the exercise.