ICD-10-CM > S00-T88 > S50-S59 > S56 > S56.3 > S56.39 > S56.391 S56.391 Other injury of extensor or abductor muscles, fascia and tendons of right thumb at forearm level Non-Billable/Non-Specific Codes S56.391A..., initial encounterS56.391D..., subsequent encounterS56.391S..., sequela