| S13.120 | Subluxation of C1/C2 cervical vertebrae | NON-BILLABLE CODE |
| S13.120A | Subluxation of C1/C2 cervical vertebrae, initial encounter | BILLABLE CODE |
| S13.120D | Subluxation of C1/C2 cervical vertebrae, subsequent encounter | BILLABLE CODE |
| S13.120S | Subluxation of C1/C2 cervical vertebrae, sequela | BILLABLE CODE |
| S13.121 | Dislocation of C1/C2 cervical vertebrae | NON-BILLABLE CODE |
| S13.121A | Dislocation of C1/C2 cervical vertebrae, initial encounter | BILLABLE CODE |
| S13.121D | Dislocation of C1/C2 cervical vertebrae, subsequent encounter | BILLABLE CODE |
| S13.121S | Dislocation of C1/C2 cervical vertebrae, sequela | BILLABLE CODE |
