ICD-10-CM > S00-T88 > S60-S69 > S66 > S66.2 > S66.20 > S66.209 S66.209 Unspecified injury of extensor muscle, fascia and tendon of unspecified thumb at wrist and hand level Non-Billable/Non-Specific Codes S66.209A..., initial encounterS66.209D..., subsequent encounterS66.209S..., sequela