S66.00 Unspecified injury of long flexor muscle, fascia and tendon of thumb at wrist and hand level

⚠ Non-Billable ICD-10-CM 2026
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The ICD-10-CM code for Unspecified injury of long flexor muscle, fascia and tendon of thumb at wrist and hand level is S66.00 (FY2026). It is a non-billable category code — select a more specific code below for claims.

Classification

Section
S60-S69: Injuries to the wrist, hand and fingers (S60-S69)
Category S66
221 codes (180 billable)
FY2026 Status
Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to S66.00:

  • Injury › muscle (and fascia) (and tendon) › thumb › flexor (forearm level) › hand level

Official Coding Guidelines

Sequence blood vessel/nerve injury first (fragment)

injury is to the blood vessels or nerves, that injury should be sequenced first.

— ICD-10-CM Official Guidelines for Coding and Reporting, FY2026, Section I.C.19.b.2
Do not assign injury codes for iatrogenic injuries; code complication

3) Iatrogenic injuries Injury codes from Chapter 19 should not be assigned for injuries that occur during, or as a result of, a medical intervention. Assign the appropriate complication code(s).

— ICD-10-CM Official Guidelines for Coding and Reporting, FY2026, Section I.C.19.b.3

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

Cite This Page

Reference S66.00 with the canonical source and edition:

S66.00 — Unspecified injury of long flexor muscle, fascia and tendon of thumb at wrist and hand level. ICD-10 Coding Pro (ICD-10-CM FY2026). https://icd10codingpro.com/codes/S66.00

Canonical URL: https://icd10codingpro.com/codes/S66.00

Related Codes

Parent Code

S66 Injury of muscle, fascia and tendon at wrist and hand level

More Specific Codes

S66.001 Unspecified injury of long flexor muscle, fascia and tendon of right thumb at wrist and hand level S66.002 Unspecified injury of long flexor muscle, fascia and tendon of left thumb at wrist and hand level S66.009 Unspecified injury of long flexor muscle, fascia and tendon of unspecified thumb at wrist and hand level

Related Codes in S66

S66 Injury of muscle, fascia and tendon at wrist and hand level S66.0 Injury of long flexor muscle, fascia and tendon of thumb at wrist and hand level S66.001 Unspecified injury of long flexor muscle, fascia and tendon of right thumb at wrist and hand level S66.002 Unspecified injury of long flexor muscle, fascia and tendon of left thumb at wrist and hand level S66.009 Unspecified injury of long flexor muscle, fascia and tendon of unspecified thumb at wrist and hand level S66.01 Strain of long flexor muscle, fascia and tendon of thumb at wrist and hand level S66.011 Strain of long flexor muscle, fascia and tendon of right thumb at wrist and hand level S66.012 Strain of long flexor muscle, fascia and tendon of left thumb at wrist and hand level S66.019 Strain of long flexor muscle, fascia and tendon of unspecified thumb at wrist and hand level S66.02 Laceration of long flexor muscle, fascia and tendon of thumb at wrist and hand level S66.021 Laceration of long flexor muscle, fascia and tendon of right thumb at wrist and hand level S66.022 Laceration of long flexor muscle, fascia and tendon of left thumb at wrist and hand level S66.029 Laceration of long flexor muscle, fascia and tendon of unspecified thumb at wrist and hand level S66.09 Other specified injury of long flexor muscle, fascia and tendon of thumb at wrist and hand level S66.091 Other specified injury of long flexor muscle, fascia and tendon of right thumb at wrist and hand level S66.092 Other specified injury of long flexor muscle, fascia and tendon of left thumb at wrist and hand level S66.099 Other specified injury of long flexor muscle, fascia and tendon of unspecified thumb at wrist and hand level S66.1 Injury of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level S66.10 Unspecified injury of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level S66.100 Unspecified injury of flexor muscle, fascia and tendon of right index finger at wrist and hand level
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Reviewed by Prajwal Shrestha, CPC, CRC
Certified Professional Coder (CPC) and Certified Risk Adjustment Coder (CRC) · AAPC Member ID 01997614 · About · Editorial policy · Content last reviewed: 2025-10-01

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