T23.5 - Corrosion of first degree of wrist and hand
T23.51 - Corrosion of first degree of thumb (nail)
T23.511 - Corrosion of first degree of right thumb (nail)
T23.512 - Corrosion of first degree of left thumb (nail)
T23.519 - Corrosion of first degree of unspecified thumb (nail)