ICD-10-CM > S00-T88 > S50-S59 > S56 > S56.9 > S56.99 > S56.999 S56.999 Other injury of unspecified muscles, fascia and tendons at forearm level, unspecified arm Non-Billable/Non-Specific Codes S56.999A..., initial encounterS56.999D..., subsequent encounterS56.999S..., sequela