ICD-10-CM > S00-T88 > S20-S29 > S21 > S21.4 > S21.40 > S21.401 S21.401 Unspecified open wound of right back wall of thorax with penetration into thoracic cavity Non-Billable/Non-Specific Codes S21.401A..., initial encounterS21.401D..., subsequent encounterS21.401S..., sequela