ICD-10-CM > S00-T88 > T20-T25 > T23 > T23.4 > T23.41 T23.41 Corrosion of unspecified degree of thumb (nail) Non-Billable/Non-Specific Codes T23.411Corrosion of unspecified degree of right thumb (nail)T23.411A..., initial encounterT23.411D..., subsequent encounterT23.411S..., sequelaT23.412Corrosion of unspecified degree of left thumb (nail)T23.412A..., initial encounterT23.412D..., subsequent encounterT23.412S..., sequelaT23.419Corrosion of unspecified degree of unspecified thumb (nail)T23.419A..., initial encounterT23.419D..., subsequent encounterT23.419S..., sequela