M40.56 identifies lumbar lordosis of unspecified type — meaning the provider has documented exaggerated inward curvature of the lumbar spine but has not specified whether the cause is postural, positional, or associated with an underlying condition.

Documentation tips

What should appear in the chart to support M40.56.

Source · Editorial brief grounded in 5 cited references ↓

• Specify the spinal region by name (lumbar vs. thoracolumbar vs. lumbosacral) — the 6th character distinction between M40.55, M40.56, and M40.57 hinges entirely on provider documentation of location.
• Document whether the lordosis is postural or structural; postural lordosis routes to M40.4x, not M40.5x — the distinction affects code family selection.
• Record imaging findings that support the diagnosis: lateral lumbar X-ray with Cobb angle measurement or radiologist description of hyperlordosis strengthens medical necessity.
• If an underlying condition (e.g., neuromuscular disease, hip pathology) is driving the lordosis, document it explicitly so the 'Code First' instruction at the M40 category level can be applied correctly.
• Note any prior spinal surgery; postprocedural lordosis must be coded from M96.- rather than M40.56, so surgical history directly changes the code selection.

Related CPT procedures

Procedure codes commonly billed with M40.56. 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 M40.56 and adjacent codes.

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

• Assigning M40.56 when the lordosis is postprocedural — postprocedural kyphosis and lordosis belongs in the M96.- category, not M40.5x.
• Using M40.56 for congenital lumbar lordosis — that condition codes to Q76.4, which is an Excludes1 exclusion at the M40 category level.
• Selecting M40.50 (site unspecified) when the record clearly states lumbar — always capture the documented region at the 6th-character level.
• Confusing M40.56 with M40.55 (thoracolumbar) or M40.57 (lumbosacral) — if the documented region is ambiguous, query the provider rather than defaulting to unspecified site.
• Failing to code the underlying disease first when lordosis is attributed to a known systemic or neuromuscular condition, violating the 'Code First' instruction at M40.

Clinical context

Source · Editorial summary grounded in 5 cited references ↓

Sibling codes

Other billable codes under M40.5 (laterality / anatomic variants).