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S13.131A vs S16.1

S13.131A (Dislocation of C2/C3 cervical vertebrae, initial encounter) compared with S16.1 (Strain of muscle, fascia and tendon at neck level), from the official CMS tabular data.

Summary

These codes can be reported together when both conditions are documented, because S13.131A lists S16.1 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named and billing status.S13.131A is “Dislocation of C2/C3 cervical vertebrae, initial encounter”; S16.1 is “Strain of muscle, fascia and tendon at neck level”. S16.1 is a non-billable header; S13.131A is billable.

Registry fact

Can these codes be reported together?

Yes, when both are documented.S13.131A lists S16.1 under Excludes2: “strain of muscle or tendon at neck level (S16.1)”. 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.S13.131A’s tabular entry: “strain of muscle or tendon at neck level (S16.1)”. The note covers S16.1.

Official ruleGuide: Excludes1 vs Excludes2

Is one more specific?

Not comparable.The codes sit in different categories; specificity is only comparable within one category.

Is one a parent or header code?

One is a header.S16.1 is a non-billable header, but S13.131A 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

S13.131A
Dislocation of C2/C3 cervical vertebrae, initial encounter
↔
S16.1
Strain of muscle, fascia and tendon at neck level

What we found

Yes, when both are documented.S13.131A carries an Excludes2 note covering S16.1: “strain of muscle or tendon at neck level (S16.1)”

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 FY2026

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

S13.131ADislocation of C2/C3 cervical vertebrae, initial encounterS16.1Strain of muscle, fascia and tendon at neck level
Billing statusBillableNon-billable header

Report instead: S16.1XXA, S16.1XXD, S16.1XXS

ClassificationS00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)
DefinitionDislocation of C2/C3 cervical vertebrae, initial encounter is a billable ICD-10-CM diagnosis code (S13.131A).Strain of muscle, fascia and tendon at neck level is a non-billable ICD-10-CM category code (S16.1).
7th characterThe appropriate 7th character is to be added to each code from category S13The appropriate 7th character is to be added to each code from category S16
Includes
avulsion of joint or ligament at neck level
laceration of cartilage, joint or ligament at neck level
sprain of cartilage, joint or ligament at neck level
traumatic hemarthrosis of joint or ligament at neck level
injuries of nape
injuries of supraclavicular region
injuries of throat
Excludes2
fracture of cervical vertebrae (S12.0-S12.3-)
strain of muscle or tendon at neck level (S16.1)
burns and corrosions (T20-T32)
effects of foreign body in esophagus (T18.1)
effects of foreign body in larynx (T17.3)
effects of foreign body in pharynx (T17.2)
effects of foreign body in trachea (T17.4)
frostbite (T33-T34)
insect bite or sting, venomous (T63.4)
sprain of joint or ligament at neck level (S13.9)
burns and corrosions (T20-T32)
effects of foreign body in esophagus (T18.1)
effects of foreign body in larynx (T17.3)
effects of foreign body in pharynx (T17.2)
effects of foreign body in trachea (T17.4)
frostbite (T33-T34)
insect bite or sting, venomous (T63.4)
Code also
any associated:
open wound of neck (S11.-)
spinal cord injury (S14.1-)
any associated open wound
any associated open wound (S11.-)

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.

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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