ICD-10-CM > S00-T88 > S50-S59 > S56 > S56.9 > S56.99 > S56.991 S56.991 Other injury of unspecified muscles, fascia and tendons at forearm level, right arm Non-Billable/Non-Specific Codes S56.991A..., initial encounterS56.991D..., subsequent encounterS56.991S..., sequela