ICD-10-CM > S00-T88 > T20-T25 > T24 > T24.4 > T24.40 > T24.409 T24.409 Corrosion of unspecified degree of unspecified site of unspecified lower limb, except ankle and foot Non-Billable/Non-Specific Codes T24.409A..., initial encounterT24.409D..., subsequent encounterT24.409S..., sequela