ICD-10-CM > S00-T88 > S50-S59 > S56 > S56.9 > S56.99 S56.99 Other injury of unspecified muscles, fascia and tendons at forearm level Non-Billable/Non-Specific Codes S56.991Other injury of unspecified muscles, fascia and tendons at forearm level, right armS56.991A..., initial encounterS56.991D..., subsequent encounterS56.991S..., sequelaS56.992Other injury of unspecified muscles, fascia and tendons at forearm level, left armS56.992A..., initial encounterS56.992D..., subsequent encounterS56.992S..., sequelaS56.999Other injury of unspecified muscles, fascia and tendons at forearm level, unspecified armS56.999A..., initial encounterS56.999D..., subsequent encounterS56.999S..., sequela