ICD-10-CM > S00-T88 > S20-S29 > S21 > S21.2 > S21.23 S21.23 Puncture wound without foreign body of back wall of thorax without penetration into thoracic cavity Non-Billable/Non-Specific Codes S21.231Puncture wound without foreign body of right back wall of thorax without penetration into thoracic cavityS21.231A..., initial encounterS21.231D..., subsequent encounterS21.231S..., sequelaS21.232Puncture wound without foreign body of left back wall of thorax without penetration into thoracic cavityS21.232A..., initial encounterS21.232D..., subsequent encounterS21.232S..., sequelaS21.239Puncture wound without foreign body of unspecified back wall of thorax without penetration into thoracic cavityS21.239A..., initial encounterS21.239D..., subsequent encounterS21.239S..., sequela