M21.4

Non-billable

Flat foot [pes planus] (acquired)

M21.4 is the ICD-10-CM code for Flat foot [pes planus] (acquired). It is a non-billable category code — use a more specific child code such as M21.40 for billing.

Status
Header (non-billable)
Chapter
M00-M99
Parent
M21
Subcodes
3
Edition
FY2026

M00-M99 Diseases of the musculoskeletal system and connective tissue

Excludes1 — not coded here

  • congenital pes planus (Q66.5-)

Frequently asked questions

What is ICD-10 code M21.4?
M21.4 is the ICD-10-CM code for "Flat foot [pes planus] (acquired)". It falls under M00-M99 Diseases of the musculoskeletal system and connective tissue.
Is M21.4 a billable code?
No — M21.4 is a non-billable header code. Use a more specific child code (such as M21.40) for billing.
What are the subcodes of M21.4?
M21.4 has 3 more specific child codes, including M21.40, M21.41, M21.42.
What is excluded from M21.4?
Excludes1 (not coded here): congenital pes planus (Q66.5-).

Source: CMS ICD-10-CM FY2026. For informational purposes only — not medical advice. See our medical disclaimer.

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