ICD-10-CM > S00-T88 > S20-S29 > S21 > S21.4 > S21.42 S21.42 Laceration with foreign body of back wall of thorax with penetration into thoracic cavity Non-Billable/Non-Specific Codes S21.421Laceration with foreign body of right back wall of thorax with penetration into thoracic cavityS21.421A..., initial encounterS21.421D..., subsequent encounterS21.421S..., sequelaS21.422Laceration with foreign body of left back wall of thorax with penetration into thoracic cavityS21.422A..., initial encounterS21.422D..., subsequent encounterS21.422S..., sequelaS21.429Laceration with foreign body of unspecified back wall of thorax with penetration into thoracic cavityS21.429A..., initial encounterS21.429D..., subsequent encounterS21.429S..., sequela