ICD-10-CM > S00-T88 > S20-S29 > S20 > S20.3 > S20.34 > S20.342 S20.342 External constriction of left front wall of thorax Non-Billable/Non-Specific Codes S20.342A..., initial encounterS20.342D..., subsequent encounterS20.342S..., sequela