1: Scratch your thumb
Use the nail of your index finger to scratch the back of your thumb.
Numbness between the tip of the thumb and the knuckle suggests sensory damage to the median nerve.
Use the nail of your index finger to scratch the back of your thumb.
Numbness between the tip of the thumb and the knuckle suggests sensory damage to the median nerve.
Keep scratching all the way to the base of the thumb.
Numbness between the knuckles suggests sensory damage to the radial nerve.
With your thumbnail, scratch the outside of your pinkie finger.
Numbness in the pinkie suggests sensory damage to the ulnar nerve.
Push your thumb against your index and middle fingers, as though trying to make a thumbs up gesture.
Loss of strength in the thumb suggests motor damage to the radial nerve.