ICD-10-CM > S00-T88 > S50-S59 > S56 > S56.0 > S56.00 S56.00 Unspecified injury of flexor muscle, fascia and tendon of thumb at forearm level Non-Billable/Non-Specific Codes S56.001Unspecified injury of flexor muscle, fascia and tendon of right thumb at forearm levelS56.001A..., initial encounterS56.001D..., subsequent encounterS56.001S..., sequelaS56.002Unspecified injury of flexor muscle, fascia and tendon of left thumb at forearm levelS56.002A..., initial encounterS56.002D..., subsequent encounterS56.002S..., sequelaS56.009Unspecified injury of flexor muscle, fascia and tendon of unspecified thumb at forearm levelS56.009A..., initial encounterS56.009D..., subsequent encounterS56.009S..., sequela