H49.2 ICD-10-CM Code: Sixth [abducent] nerve palsy

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for H49.2 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on H49.2 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for H49.2

MedCoder structured workflow — derived from this code’s own official record

Before you code H49.2

1. H49.2 is not reportable as written. Select the more specific code beneath it that the documentation supports. Codes are reported to the highest level of specificity the classification provides (Guidelines I.B.2).

   ReviewH49.20, H49.21, H49.22, H49.23

   See the relationships section · Guide: How to choose an ICD-10-CM code →

Choose the right path

1. Does the documentation support one of the more specific codes beneath H49.2?
   Yes → Select that code and continue the checks below on its own page.
   No → H49.2 cannot be reported as written; query for the specificity its subcategory needs.

   ReviewH49.20, H49.21, H49.22, H49.23

Consider H49.2. Then confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement

Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).

Official instructions as workflow

• Excludes2 — not part of H49.2(4 notes)

  Coding workflow: The conditions named in this note are not included in H49.2. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

  CompareH52.51, H51.2, G23.1, H55

  See the official tabular notes · Guidelines I.A.12.b

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Don’t confuse H49.2 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of H49.2 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• H49.9— Specificity relationship (Review)

  Overlapping diagnoses in the same category.

  Overlapping codes in the same category — the documentation decides which is the more specific fit.

  What moves you there: A record that documents no more than “Unspecified paralytic strabismus” takes H49.9; specificity in the record moves it back here.

  Full comparison: H49.2 vs H49.9 →

• H52.51— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of internal ophthalmoplegia adds H52.51; it is not part of this code and both may be reported when both are documented.

  Full comparison: H49.2 vs H52.51 →

• H51.2— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of internuclear ophthalmoplegia adds H51.2; it is not part of this code and both may be reported when both are documented.

  Full comparison: H49.2 vs H51.2 →

• G23.1— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of progressive supranuclear ophthalmoplegia adds G23.1; it is not part of this code and both may be reported when both are documented.

  Full comparison: H49.2 vs G23.1 →

• H55— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of nystagmus and other irregular eye movements adds H55; it is not part of this code and both may be reported when both are documented.

  Full comparison: H49.2 vs H55 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Verify Before Coding

• Not billable as written — a more specific code is required: H49.20, H49.21, H49.22, H49.23.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name H49.2 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Excludes2 note: G52 — Disorders of other cranial nerves (via H49.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Related Codes

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Strabismus”; these codes share that main term but sit in a different category of the Tabular List.

H50.00 — Unspecified esotropia (convergent concomitant), H50.01 — Monocular esotropia (convergent concomitant, monocular), H50.02 — Monocular esotropia with A pattern (convergent concomitant, monocular, with, A pattern), H50.03 — Monocular esotropia with V pattern (convergent concomitant, monocular, with, V pattern), H50.04 — Monocular esotropia with other noncomitancies (convergent concomitant, monocular, with, specified nonconcomitances NEC), H50.05 — Alternating esotropia (convergent concomitant, alternating), H50.06 — Alternating esotropia with A pattern (convergent concomitant, alternating, with, A pattern), H50.07 — Alternating esotropia with V pattern (convergent concomitant, alternating, with, V pattern), H50.08 — Alternating esotropia with other noncomitancies (convergent concomitant, alternating, with, specified nonconcomitances NEC), H50.10 — Unspecified exotropia (divergent concomitant), H50.11 — Monocular exotropia (divergent concomitant, monocular), H50.12 — Monocular exotropia with A pattern (divergent concomitant, monocular, with, A pattern), H50.13 — Monocular exotropia with V pattern (divergent concomitant, monocular, with, V pattern), H50.14 — Monocular exotropia with other noncomitancies (divergent concomitant, monocular, with, specified noncomitances NEC), H50.15 — Alternating exotropia (divergent concomitant, alternating), H50.16 — Alternating exotropia with A pattern (divergent concomitant, alternating, with, A pattern), H50.17 — Alternating exotropia with V pattern (divergent concomitant, alternating, with, V pattern), H50.18 — Alternating exotropia with other noncomitancies (divergent concomitant, alternating, with, specified noncomitances NEC), H50.2 — Vertical strabismus (vertical), H50.30 — Unspecified intermittent heterotropia (heterotropia, intermittent), +20 more

Contextual Map

Every relationship of H49.2 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run H49.2 with this related code in Claim Check

Hierarchy

• H00-H59 — Chapter 7: Diseases of the Eye and Adnexa (H00-H59) (H00-H59)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• H49-H52 — Disorders of ocular muscles, binocular movement, accommodation and refraction[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes2 notes

• G52 — Disorders of other cranial nerves[Excludes2](via H49.-): “paralytic strabismus due to nerve palsy (H49.0-H49.2)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Nearest codes (37)

• H49 — Paralytic strabismus[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• H49.0 — Third [oculomotor] nerve palsy[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• H49.00 — Third [oculomotor] nerve palsy, unspecified eye[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• H49.01 — Third [oculomotor] nerve palsy, right eye[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• H49.02 — Third [oculomotor] nerve palsy, left eye[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• H49.03 — Third [oculomotor] nerve palsy, bilateral[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• H49.1 — Fourth [trochlear] nerve palsy[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• H49.10 — Fourth [trochlear] nerve palsy, unspecified eye[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 29 more

Change history

• FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Common coding questions

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data

CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page

Claim edits Official source data

CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page

Change history and date-of-service validity Official source data

CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page

Comparisons, relationships and the contextual map MedCoder structured relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder explanation

Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Nearest Codes in This Family

Official ICD-10-CM classifications closest to H49.2 in its code family, with their registry titles.

• H49.1 — Fourth [trochlear] nerve palsy
• H49.10 — Fourth [trochlear] nerve palsy, unspecified eye
• H49.11 — Fourth [trochlear] nerve palsy, right eye
• H49.12 — Fourth [trochlear] nerve palsy, left eye
• H49.13 — Fourth [trochlear] nerve palsy, bilateral
• H49.20 — Sixth [abducent] nerve palsy, unspecified eye
• H49.21 — Sixth [abducent] nerve palsy, right eye
• H49.22 — Sixth [abducent] nerve palsy, left eye
• H49.23 — Sixth [abducent] nerve palsy, bilateral
• H49.3 — Total (external) ophthalmoplegia

View all codes in the H49 family