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