T23.42 - Corrosion of unspecified degree of single finger (nail) except thumb T23.4 - Corrosion of unspecified degree of wrist and hand T23.42 - Corrosion of unspecified degree of single finger (nail) except thumb T23.421 - Corrosion of unspecified degree of single right finger (nail) except thumb T23.422 - Corrosion of unspecified degree of single left finger (nail) except thumb T23.429 - Corrosion of unspecified degree of unspecified single finger (nail) except thumb