2026 ICD-10-CM Diagnosis Code S66Injury of muscle, fascia and tendon at wrist and hand level

ICD-10-CM Codes›S00–T88›S60-S69›S66

ICD-10-CM S66
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S66 is a non-billable ICD-10-CM category code for injury of muscle, fascia and tendon at wrist and hand level, so it cannot be submitted on claims. Use a more specific code from this category instead, such as S66.001A, S66.001D, S66.001S, and S66.002A.

Code Identity

ICD-10-CM Code
S66
Billable Status
No — Non-Billable Category
Code Describes
Injury of muscle, fascia and tendon at wrist and hand level
Short Description
Injury of muscle, fascia and tendon at wrist and hand level
Same as the full description in the CMS dataset.
Chapter
S60-S69
Injuries to the wrist, hand and fingers

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS60-S69Injuries to the wrist, hand and fingers
CategoryS66Injury of muscle, fascia and tendon at wrist and hand level
This CodeS66Injury of muscle, fascia and tendon at wrist and hand level

Specific Coding for Injury of muscle, fascia and tendon at wrist and hand levelOverview

Non-specific codes like S66 require more characters. Use one of these billable codes instead:

  • S66.0 for Injury of long flexor muscle, fascia and tendon of thumb at wrist and hand level

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

  • S66.01 for Strain of long flexor muscle, fascia and tendon of thumb at wrist and hand level

  • S66.02 for Laceration of long flexor muscle, fascia and tendon of thumb at wrist and hand level

  • S66.09 for Other specified injury of long flexor muscle, fascia and tendon of thumb at wrist and hand level

  • S66.1 for Injury of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level

  • S66.10 for Unspecified injury of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level

  • S66.11 for Strain of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level

  • S66.12 for Laceration of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level

  • S66.19 for Other injury of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level

  • S66.2 for Injury of extensor muscle, fascia and tendon of thumb at wrist and hand level

  • S66.20 for Unspecified injury of extensor muscle, fascia and tendon of thumb at wrist and hand level

  • S66.21 for Strain of extensor muscle, fascia and tendon of thumb at wrist and hand level

  • S66.22 for Laceration of extensor muscle, fascia and tendon of thumb at wrist and hand level

  • S66.29 for Other specified injury of extensor muscle, fascia and tendon of thumb at wrist and hand level

  • S66.3 for Injury of extensor muscle, fascia and tendon of other and unspecified finger at wrist and hand level

  • S66.30 for Unspecified injury of extensor muscle, fascia and tendon of other and unspecified finger at wrist and hand level

  • S66.31 for Strain of extensor muscle, fascia and tendon of other and unspecified finger at wrist and hand level

  • S66.32 for Laceration of extensor muscle, fascia and tendon of other and unspecified finger at wrist and hand level

  • S66.39 for Other injury of extensor muscle, fascia and tendon of other and unspecified finger at wrist and hand level

  • S66.4 for Injury of intrinsic muscle, fascia and tendon of thumb at wrist and hand level

  • S66.40 for Unspecified injury of intrinsic muscle, fascia and tendon of thumb at wrist and hand level

  • S66.41 for Strain of intrinsic muscle, fascia and tendon of thumb at wrist and hand level

  • S66.42 for Laceration of intrinsic muscle, fascia and tendon of thumb at wrist and hand level

  • S66.49 for Other specified injury of intrinsic muscle, fascia and tendon of thumb at wrist and hand level

  • S66.5 for Injury of intrinsic muscle, fascia and tendon of other and unspecified finger at wrist and hand level

  • S66.50 for Unspecified injury of intrinsic muscle, fascia and tendon of other and unspecified finger at wrist and hand level

  • S66.51 for Strain of intrinsic muscle, fascia and tendon of other and unspecified finger at wrist and hand level

  • S66.52 for Laceration of intrinsic muscle, fascia and tendon of other and unspecified finger at wrist and hand level

  • S66.59 for Other injury of intrinsic muscle, fascia and tendon of other and unspecified finger at wrist and hand level

  • S66.8 for Injury of other specified muscles, fascia and tendons at wrist and hand level

  • S66.80 for Unspecified injury of other specified muscles, fascia and tendons at wrist and hand level

  • S66.81 for Strain of other specified muscles, fascia and tendons at wrist and hand level

  • S66.82 for Laceration of other specified muscles, fascia and tendons at wrist and hand level

  • S66.89 for Other injury of other specified muscles, fascia and tendons at wrist and hand level

  • S66.9 for Injury of unspecified muscle, fascia and tendon at wrist and hand level

  • S66.90 for Unspecified injury of unspecified muscle, fascia and tendon at wrist and hand level

  • S66.91 for Strain of unspecified muscle, fascia and tendon at wrist and hand level

  • S66.92 for Laceration of unspecified muscle, fascia and tendon at wrist and hand level

  • S66.99 for Other injury of unspecified muscle, fascia and tendon at wrist and hand level

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Injury of muscle, fascia and tendon at wrist and hand level (S66). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Code Also

  • any associated open wound S61

Type 2 Excludes

  • sprain of joints and ligaments of wrist and hand S63

7th Character Note

  • The appropriate 7th character is to be added to each code from category S66

7th Character

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Patient EducationClinical

Hand Injuries and Disorders

No matter how old you are or what you do for a living, you are always using your hands. When there is something wrong with them, you may not be able to do your regular activities.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About S66Overview

Is S66 (Injury of muscle, fascia and tendon at wrist and hand level) a billable code?

No. This is a category header that groups the codes for injury of muscle, fascia and tendon at wrist and hand level, and headers cannot be submitted on claims. Claims for injury of muscle, fascia and tendon at wrist and hand level need a more specific code from this category, such as S66.001A, S66.001D, and S66.001S.