An abnormality of nail growth associated with median nerve damage.

It has been recognised for a long time that damage to the median or ulnar nerves is usually followed by slowing of growth of the fingernails. In the past, this has always been ascribed to immobilization of the appropriate digits, rather than to a neurotrophic factor. No other nail changes appear to have been described in association with nerve damage. We present two patients with marked nail changes following median nerve injury, in which immobilization does not appear to be responsible.