ICD-10-CM > S00-T88 > S20-S29 > S20 > S20.4 > S20.40 S20.40 Unspecified superficial injuries of back wall of thorax Non-Billable/Non-Specific Codes S20.401Unspecified superficial injuries of right back wall of thoraxS20.401A..., initial encounterS20.401D..., subsequent encounterS20.401S..., sequelaS20.402Unspecified superficial injuries of left back wall of thoraxS20.402A..., initial encounterS20.402D..., subsequent encounterS20.402S..., sequelaS20.409Unspecified superficial injuries of unspecified back wall of thoraxS20.409A..., initial encounterS20.409D..., subsequent encounterS20.409S..., sequela