T23.52 - Corrosion of first degree of single finger (nail) except thumb T23.5 - Corrosion of first degree of wrist and hand T23.52 - Corrosion of first degree of single finger (nail) except thumb T23.521 - Corrosion of first degree of single right finger (nail) except thumb T23.522 - Corrosion of first degree of single left finger (nail) except thumb T23.529 - Corrosion of first degree of unspecified single finger (nail) except thumb