M66.1
Non-Billable

Rupture of synovium

Non-Billable / Non-Specific Code

What is Rupture of synovium?

ICD-10-CM M66.1 is the diagnosis code for Rupture of synovium. 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.

💡 Inclusions
â„šī¸ Excludes2

Coding Guidelines for M66.1

✅ This Code Includes

  • Rupture of synovial cyst

â„šī¸ Type 2 Excludes (Code separately if applicable)

The following conditions are not included in M66.1. If the patient has both, code each condition separately:

  • rupture of popliteal cyst (M66.0)

ICD-10-CM Code Hierarchy

Understanding where M66.1 sits in the ICD-10-CM classification helps ensure proper coding:

Sub-Codes 8 entries
M66.10Rupture of synovium, unspecified jointBillableM66.11Rupture of synovium, shoulderNon-BillableM66.111Rupture of synovium, right shoulderBillableM66.112Rupture of synovium, left shoulderBillableM66.119Rupture of synovium, unspecified shoulderBillableM66.12Rupture of synovium, elbowNon-BillableM66.121Rupture of synovium, right elbowBillableM66.122Rupture of synovium, left elbowBillableM66.129Rupture of synovium, unspecified elbowBillableM66.13Rupture of synovium, wristNon-BillableM66.131Rupture of synovium, right wristBillableM66.132Rupture of synovium, left wristBillableM66.139Rupture of synovium, unspecified wristBillableM66.14Rupture of synovium, hand and fingersNon-BillableM66.141Rupture of synovium, right handBillableM66.142Rupture of synovium, left handBillableM66.143Rupture of synovium, unspecified handBillableM66.144Rupture of synovium, right finger(s)BillableM66.145Rupture of synovium, left finger(s)BillableM66.146Rupture of synovium, unspecified finger(s)BillableM66.15Rupture of synovium, hipNon-BillableM66.151Rupture of synovium, right hipBillableM66.152Rupture of synovium, left hipBillableM66.159Rupture of synovium, unspecified hipBillableM66.17Rupture of synovium, ankle, foot and toesNon-BillableM66.171Rupture of synovium, right ankleBillableM66.172Rupture of synovium, left ankleBillableM66.173Rupture of synovium, unspecified ankleBillableM66.174Rupture of synovium, right footBillableM66.175Rupture of synovium, left footBillableM66.176Rupture of synovium, unspecified footBillableM66.177Rupture of synovium, right toe(s)BillableM66.178Rupture of synovium, left toe(s)BillableM66.179Rupture of synovium, unspecified toe(s)BillableM66.18Rupture of synovium, other siteBillable
Related Codes

Frequently Asked Questions

Is M66.1 a billable ICD-10-CM code?

No, M66.1 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.

What does M66.1 mean?

M66.1 is the ICD-10-CM diagnosis code for "Rupture of synovium". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.

What is the parent code of M66.1?

The parent code of M66.1 is M66 ("Spontaneous rupture of synovium and tendon"). M66.1 provides a more specific classification within this category.

What section is M66.1 in?

M66.1 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 M66.1?

M66.1 has 8 sub-code(s) that provide more specific detail: M66.10, M66.11, M66.12, M66.13, M66.14 and more.

When should I use M66.1?

Use M66.1 when the patients documented diagnosis matches "Rupture of synovium" 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 Rupture of synovium?

The ICD-10-CM code for Rupture of synovium is M66.1.

Can M66.1 be used for primary diagnosis?

No, M66.1 is non-billable. Use a more specific sub-code for primary diagnosis billing.

What chapter is M66.1 in?

M66.1 is in Chapter 13 of the ICD-10-CM Tabular List.

Is M66.1 valid for 2026?

Yes, M66.1 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.

See Also

← PreviousM66.0Rupture of popliteal cystNext →M66.10Rupture of synovium, unspecified joint
Code Details
M66.1
Rupture of synovium
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