Osteochondrosis of the vertebral ossification centers occurring at the cervicothoracic junction (C7-T1 region) in a skeletally mature adult patient.

Documentation tips

What should appear in the chart to support M42.13.

Source · Editorial brief grounded in 5 cited references ↓

• Provider must explicitly name the cervicothoracic region (or C7-T1 junction) as the affected site — imaging findings alone do not justify M42.13 without physician documentation of region.
• Document whether findings are adult-onset; if the patient is skeletally immature or juvenile, M42.03 applies instead.
• Record imaging modality used (X-ray, MRI, CT) along with specific findings such as endplate irregularity, disc space narrowing, or Schmorl's nodes at the cervicothoracic junction.
• If multiple spinal regions are involved, the provider should list each affected region to support M42.19 (multiple sites) rather than defaulting to M42.13 alone.
• For outpatient therapy billing under CMS LCD A53064, confirm M42.13 is listed as a covered diagnosis in the plan of care documentation.

Related CPT procedures

Procedure codes commonly billed with M42.13. Linking the right diagnosis to the right procedure is what establishes medical necessity.

Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis

Common coding pitfalls

The recurring mistakes coders make with M42.13 and adjacent codes.

Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓

• Coding M42.13 when documentation only states 'cervical spine' — the cervicothoracic region is distinct from the cervical region (M42.12) and requires the junction to be specifically identified.
• Using M42.13 alongside M42.12 or M42.14 for a single patient encounter when the correct code is M42.19 (multiple sites in spine).
• Defaulting to M42.10 (site unspecified) when the provider has documented the cervicothoracic region — always code to the highest specificity supported by documentation.
• Confusing adult osteochondrosis (M42.13) with juvenile osteochondrosis (M42.03) — verify patient age and skeletal maturity in the record before selecting the parent category M42.1 vs. M42.0.
• Appending a 7th-character extension to M42.13 — M-codes do not use 7th-character encounter designators; the code is valid as a 6-character billable code.

Clinical context

Source · Editorial summary grounded in 5 cited references ↓

Sibling codes

Other billable codes under M42.1 (laterality / anatomic variants).