ICD-10-CM > S00-T88 > S60-S69 > S66 > S66.4 > S66.42 > S66.421 S66.421 Laceration of intrinsic muscle, fascia and tendon of right thumb at wrist and hand level Non-Billable/Non-Specific Codes S66.421A..., initial encounterS66.421D..., subsequent encounterS66.421S..., sequela