ICD-10-CM > S00-T88 > S50-S59 > S56 > S56.5 > S56.59 > S56.599 S56.599 Other injury of other extensor muscle, fascia and tendon at forearm level, unspecified arm Non-Billable/Non-Specific Codes S56.599A..., initial encounterS56.599D..., subsequent encounterS56.599S..., sequela