M66.3
Non-Billable

Spontaneous rupture of flexor tendons

Non-Billable / Non-Specific Code

What is Spontaneous rupture of flexor tendons?

ICD-10-CM M66.3 is the diagnosis code for Spontaneous rupture of flexor tendons. This code falls under the section "Disorders of synovium and tendon" within Chapter 13 — Diseases of the musculoskeletal system and connective tissue (M00-M99). It is a non-billable/non-specific ICD-10-CM code that should not be used for reimbursement. A more specific sub-code is required for billing. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.

Coding Guidelines for M66.3

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.

ICD-10-CM Code Hierarchy

Understanding where M66.3 sits in the ICD-10-CM classification helps ensure proper coding:

Sub-Codes 10 entries
M66.30Spontaneous rupture of flexor tendons, unspecified siteBillableM66.31Spontaneous rupture of flexor tendons, shoulderNon-BillableM66.311Spontaneous rupture of flexor tendons, right shoulderBillableM66.312Spontaneous rupture of flexor tendons, left shoulderBillableM66.319Spontaneous rupture of flexor tendons, unspecified shoulderBillableM66.32Spontaneous rupture of flexor tendons, upper armNon-BillableM66.321Spontaneous rupture of flexor tendons, right upper armBillableM66.322Spontaneous rupture of flexor tendons, left upper armBillableM66.329Spontaneous rupture of flexor tendons, unspecified upper armBillableM66.33Spontaneous rupture of flexor tendons, forearmNon-BillableM66.331Spontaneous rupture of flexor tendons, right forearmBillableM66.332Spontaneous rupture of flexor tendons, left forearmBillableM66.339Spontaneous rupture of flexor tendons, unspecified forearmBillableM66.34Spontaneous rupture of flexor tendons, handNon-BillableM66.341Spontaneous rupture of flexor tendons, right handBillableM66.342Spontaneous rupture of flexor tendons, left handBillableM66.349Spontaneous rupture of flexor tendons, unspecified handBillableM66.35Spontaneous rupture of flexor tendons, thighNon-BillableM66.351Spontaneous rupture of flexor tendons, right thighBillableM66.352Spontaneous rupture of flexor tendons, left thighBillableM66.359Spontaneous rupture of flexor tendons, unspecified thighBillableM66.36Spontaneous rupture of flexor tendons, lower legNon-BillableM66.361Spontaneous rupture of flexor tendons, right lower legBillableM66.362Spontaneous rupture of flexor tendons, left lower legBillableM66.369Spontaneous rupture of flexor tendons, unspecified lower legBillableM66.37Spontaneous rupture of flexor tendons, ankle and footNon-BillableM66.371Spontaneous rupture of flexor tendons, right ankle and footBillableM66.372Spontaneous rupture of flexor tendons, left ankle and footBillableM66.379Spontaneous rupture of flexor tendons, unspecified ankle and footBillableM66.38Spontaneous rupture of flexor tendons, other siteBillableM66.39Spontaneous rupture of flexor tendons, multiple sitesBillable
Related Codes

Frequently Asked Questions

Is M66.3 a billable ICD-10-CM code?

No, M66.3 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.

What does M66.3 mean?

M66.3 is the ICD-10-CM diagnosis code for "Spontaneous rupture of flexor tendons". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.

What is the parent code of M66.3?

The parent code of M66.3 is M66 ("Spontaneous rupture of synovium and tendon"). M66.3 provides a more specific classification within this category.

What section is M66.3 in?

M66.3 is located in Section M65-M67 — "Disorders of synovium and tendon" within Chapter 13 of the ICD-10-CM Tabular List.

What are the sub-codes of M66.3?

M66.3 has 10 sub-code(s) that provide more specific detail: M66.30, M66.31, M66.32, M66.33, M66.34 and more.

When should I use M66.3?

Use M66.3 when the patients documented diagnosis matches "Spontaneous rupture of flexor tendons" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.

People Also Ask

What is the ICD-10 code for Spontaneous rupture of flexor tendons?

The ICD-10-CM code for Spontaneous rupture of flexor tendons is M66.3.

Can M66.3 be used for primary diagnosis?

No, M66.3 is non-billable. Use a more specific sub-code for primary diagnosis billing.

What chapter is M66.3 in?

M66.3 is in Chapter 13 of the ICD-10-CM Tabular List.

Is M66.3 valid for 2026?

Yes, M66.3 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.

See Also

← PreviousM66.29Spontaneous rupture of extensor tendons, multiple sitesNext →M66.30Spontaneous rupture of flexor tendons, unspecified site
Code Details
M66.3
Spontaneous rupture of flexor tendons
Non-Billable / Non-Specific Code
13 — Diseases of the musculoskeletal system and connective tissue (M00-M99)
M65-M67 — Disorders of synovium and tendon
2026 ICD-10-CM