Billable / Specific Code
ICD-10-CM M21.40 is the diagnosis code for Flat foot [pes planus] (acquired), unspecified foot. This code falls under the section "Other joint disorders" within Chapter 13 — Diseases of the musculoskeletal system and connective tissue (M00-M99). It is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
Always refer to the official ICD-10-CM Tabular List for complete coding guidelines. Ensure documentation supports the specificity of the code selected. When in doubt, consult a certified medical coder or the latest CMS guidelines.
Understanding where M21.40 sits in the ICD-10-CM classification helps ensure proper coding:
Yes, M21.40 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
M21.40 is the ICD-10-CM diagnosis code for "Flat foot [pes planus] (acquired), unspecified foot". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
The parent code of M21.40 is M21.4 ("Flat foot [pes planus] (acquired)"). M21.40 provides a more specific classification within this category.
M21.40 is located in Section M20-M25 — "Other joint disorders" within Chapter 13 of the ICD-10-CM Tabular List.
Use M21.40 when the patients documented diagnosis matches "Flat foot [pes planus] (acquired), unspecified foot" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Flat foot [pes planus] (acquired), unspecified foot is M21.40.
Yes, M21.40 can be used as a primary diagnosis code since it is billable and specific.
M21.40 is in Chapter 13 of the ICD-10-CM Tabular List.
Yes, M21.40 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.