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S66.2 vs S66.323D

S66.2 (Injury of extensor muscle, fascia and tendon of thumb at wrist and hand level) compared with S66.323D (Laceration of extensor muscle, fascia and tendon of left middle finger at wrist and hand level, subsequent encounter), from the official CMS tabular data.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Summary

These codes can be reported together when both conditions are documented, because S66.323D lists S66.2 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named and billing status.S66.2 is “Injury of extensor muscle, fascia and tendon of thumb at wrist and hand level”; S66.323D is “Laceration of extensor muscle, fascia and tendon of left middle finger at wrist and hand level, subsequent encounter”. S66.2 is a non-billable header; S66.323D is billable.

Registry fact

Can these codes be reported together?

Yes, when both are documented.S66.323D lists S66.2 under Excludes2: “Injury of extensor muscle, fascia and tendon of thumb at wrist and hand level (S66.2-)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code.

Official rule

Is there an Excludes2 relationship?

Yes.S66.323D’s tabular entry: “Injury of extensor muscle, fascia and tendon of thumb at wrist and hand level (S66.2-)”. The note covers S66.2.

Official ruleGuide: Excludes1 vs Excludes2

Is one more specific?

No.Neither is a subdivision of the other, and neither title is the unspecified form; they describe different conditions within category S66.

Registry fact

Is one a parent or header code?

One is a header.S66.2 is a non-billable header, but S66.323D is not one of its subdivisions.

Registry fact

Are there sequencing instructions?

None.Neither entry carries a Code First or Use Additional Code note that names the other.

Official rule

Are there other coding relationships?

None found.No laterality, encounter-phase, Table of Neoplasms, Table of Drugs and Chemicals, or history-versus-active-disease relationship links these codes.

MedCoder-derived

Official rule: a tabular instructional note or a section of the ICD-10-CM Official Guidelines, quoted as published. Registry fact: the codes’ own published attributes (titles, billable status, position in the hierarchy, code set). MedCoder-derived: a reading MedCoder computes from those facts; it is not itself a rule. How to read the labels

Can these codes be reported together?

Informational

Excludes2 relationship

S66.323D
Laceration of extensor muscle, fascia and tendon of left middle finger at wrist and hand level, subsequent encounter
↔
S66.2
Injury of extensor muscle, fascia and tendon of thumb at wrist and hand level

What we found

Yes, when both are documented.S66.323D carries an Excludes2 note covering S66.2: “Injury of extensor muscle, fascia and tendon of thumb at wrist and hand level (S66.2-)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

What to review

Report both only when the documentation supports both conditions; otherwise report the one documented.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes2 note means the excluded condition is not part of the code above it, but a patient can have both. Report both when both are documented.

Source / rule

CMS ICD-10-CM tabular instructional notes

Official guidance behind these answers

  • Section I.A.12.b — Excludes2 · applies to: Excludes2

    A type 2 Excludes note represents “Not included here.” An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

    ICD-10-CM Official Guidelines FY2027

Quoted from the ICD-10-CM Official Guidelines for Coding and Reporting in effect for the release shown. The tabular notes above are the code-level instruction; these sections are the convention that says how such a note is applied. Source document (CMS PDF) · Release and checksum

Side by side

Similar descriptions do not make codes interchangeable. The documentation and the official instructions decide which code applies.

Official descriptionDiffers
S66.2

Injury of extensor muscle, fascia and tendon of thumb at wrist and hand level

S66.323D

Laceration of extensor muscle, fascia and tendon of left middle finger at wrist and hand level, subsequent encounter

StatusDiffers
S66.2
Non-billable header

A header is not reported on a claim; a code beneath it is.

Report instead: S66.201A, S66.201D, S66.201S, S66.202A, S66.202D

S66.323D
Billable
Excludes2Differs
S66.2
  • sprain of joints and ligaments of wrist and hand (S63.-)
  • burns and corrosions (T20-T32)
  • frostbite (T33-T34)
  • insect bite or sting, venomous (T63.4)
S66.323D
  • Injury of extensor muscle, fascia and tendon of thumb at wrist and hand level (S66.2-)
  • sprain of joints and ligaments of wrist and hand (S63.-)
  • burns and corrosions (T20-T32)
  • frostbite (T33-T34)
  • insect bite or sting, venomous (T63.4)
Code alsoSame for both
  • any associated open wound (S61.-)
CategorySame for both

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

ChapterSame for both

S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)

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

No Excludes1, Code first, Use additional code and Includes note at either code.

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on. In a row that differs, notes every code shares are dimmed.

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Derived from the official CMS ICD-10-CM tabular data (FY2027). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources