ICD-10-CM > S00-T88 > S10-S19 > S13 > S13.1 > S13.12 S13.12 Subluxation and dislocation of C1/C2 cervical vertebrae Non-Billable/Non-Specific Applicable To Subluxation and dislocation of atlantoaxial joint Codes S13.120Subluxation of C1/C2 cervical vertebraeS13.120A..., initial encounterS13.120D..., subsequent encounterS13.120S..., sequelaS13.121Dislocation of C1/C2 cervical vertebraeS13.121A..., initial encounterS13.121D..., subsequent encounterS13.121S..., sequela