ICD-10-CM > S00-T88 > T20-T25 > T23 > T23.7 > T23.71 T23.71 Corrosion of third degree of thumb (nail) Non-Billable/Non-Specific Codes T23.711Corrosion of third degree of right thumb (nail)T23.711A..., initial encounterT23.711D..., subsequent encounterT23.711S..., sequelaT23.712Corrosion of third degree of left thumb (nail)T23.712A..., initial encounterT23.712D..., subsequent encounterT23.712S..., sequelaT23.719Corrosion of third degree of unspecified thumb (nail)T23.719A..., initial encounterT23.719D..., subsequent encounterT23.719S..., sequela