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M21.249 ICD-10-CM Code: Flexion deformity, unspecified finger joints

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
3 Excludes1 · 3 Excludes2

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v44, Appendix B.

  • MS-DRG 564 — OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITH MCC (MDC 08)
  • MS-DRG 565 — OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITH CC (MDC 08)
  • MS-DRG 566 — OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITHOUT CC/MCC (MDC 08)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for M21.249 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2027Effective: October 1, 2026

Trace:FY2027 changesChange historyRelease, file and checksum

Notes without a marker are published on M21.249 itself; “inherited from” names the category or block whose note applies here.

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Source: inherited from M21

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Coder workflow for M21.249

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

Before you code M21.249

  1. Unspecified does not mean incorrect. When the record gives no greater specificity, M21.249 may be the appropriate code. Check the record for detail that supports a more specific sibling. An unspecified code is for records that do not provide the detail a more specific code needs; a query, not an assumption, is the route to specificity (Guidelines I.A.9.b, I.B.18).

    ReviewM21.241, M21.242

    See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →

  2. Laterality is coded in this family. Confirm the side documented — right, left, or bilateral — and select the matching code (this page’s code: unspecified). The unspecified-side code applies only when the record states no side. Laterality is assigned from the documented side; where a bilateral code exists and both sides are documented, it is used instead of two unilateral codes (Guidelines I.B.13).

    ReviewM21.241 · right, M21.242 · left

    Guide: Laterality coding →

  3. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with M21.249. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the record document the detail a more specific sibling code needs?
    Yes → Review the specific siblings in this subcategory.
    No → Continue — M21.249 is appropriate when the documentation goes no further.

    ReviewM21.241, M21.242

  2. Does the documentation support a condition named in M21.249’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

    ReviewZ89

  3. Is the side documented?
    Yes → Select the code for the documented side (or the bilateral code when both sides are documented and one exists).
    No → Use the unspecified-side code only when the record states no side; a query is the alternative.

    ReviewM21.241 · right, M21.242 · left

Consider M21.249. 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).
Laterality
Right, left or bilateral as documented; unspecified only when the record states no side (Guidelines I.B.13).
Any detail beyond this code’s title
What the record states that a more specific sibling code would capture — or its absence, which itself supports the unspecified code.

Official instructions as workflow

  • Excludes1 — check before selecting M21.249(3 notes)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with M21.249: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareZ89

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

  • Excludes2 — not part of M21.249(3 notes)

    Coding workflow: The conditions named in this note are not included in M21.249. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareM20, M91.2

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

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: The provider documents the condition in the terms of this code’s title and records no further detail.

Coding question: Is a more specific sibling code supportable?

Path: Review the specific siblings in this subcategory and what each requires the record to state.

Reason: A more specific code needs documentation of the distinguishing element; without it the unspecified code is appropriate, and a provider query is the route to specificity (Guidelines I.A.9.b, I.B.18).

ReviewM21.241, M21.242

Documentation: Both the condition M21.249 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

ReviewZ89

Documentation: The record documents the condition on one side only.

Coding question: Which code in this family applies?

Path: Select the sibling code for the documented side.

Reason: Laterality is assigned from the documented side; the unspecified-side code is for records that state no side (Guidelines I.B.13).

ReviewM21.241 · right, M21.242 · left

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 M21.249 with…

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

The codes most likely to be picked instead of M21.249 — 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.

  • Z89— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of acquired absence of limb moves the case to Z89; the two are not reported together unless documented as unrelated.

    Full comparison: M21.249 vs Z89 →

  • Q71— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of congenital absence of limbs moves the case to Q71; the two are not reported together unless documented as unrelated.

    Full comparison: M21.249 vs Q71 →

  • Q73— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of congenital absence of limbs moves the case to Q73; the two are not reported together unless documented as unrelated.

    Full comparison: M21.249 vs Q73 →

  • Q65— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of congenital deformities and malformations of limbs moves the case to Q65; the two are not reported together unless documented as unrelated.

    Full comparison: M21.249 vs Q65 →

  • Q66— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of congenital deformities and malformations of limbs moves the case to Q66; the two are not reported together unless documented as unrelated.

    Full comparison: M21.249 vs Q66 →

  • Q68— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of congenital deformities and malformations of limbs moves the case to Q68; the two are not reported together unless documented as unrelated.

    Full comparison: M21.249 vs Q68 →

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.

Code Overview

Flexion deformity, unspecified finger joints is a billable ICD-10-CM diagnosis code (M21.249).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

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 M21.249 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 2 Excludes1 notes across 2 chapters: M23 — Internal derangement of knee (via M21.-), Z89 — Acquired absence of limb (via M21.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 3 Excludes2 notes: M24.5 — Contracture of joint (via M21.-), M25 — Other joint disorder, not elsewhere classified (via M21.-), M95 — Other acquired deformities of musculoskeletal system and connective tissue (via M21.-).

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

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 3 MS-DRGs: DRG 564 (MDC 08), DRG 565 (MDC 08), DRG 566 (MDC 08).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):MUS023 — Acquired deformities (excluding foot) (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same condition, opposite side

Same category and title, differing only in which side of the body is affected.

M21.241 — Flexion deformity, right finger joints (right)Compare M21.249 vs M21.241 →, M21.242 — Flexion deformity, left finger joints (left)Compare M21.249 vs M21.242 →

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Acquired deformities (excluding foot)).

M21.212 — Flexion deformity, left shoulder, M21.219 — Flexion deformity, unspecified shoulder, M21.221 — Flexion deformity, right elbow, M21.222 — Flexion deformity, left elbow, M21.229 — Flexion deformity, unspecified elbow, M21.231 — Flexion deformity, right wrist, M21.232 — Flexion deformity, left wrist, M21.239 — Flexion deformity, unspecified wrist, M21.241 — Flexion deformity, right finger joints, M21.242 — Flexion deformity, left finger joints, M21.251 — Flexion deformity, right hip, M21.252 — Flexion deformity, left hip, M21.259 — Flexion deformity, unspecified hip, M21.261 — Flexion deformity, right knee, M21.262 — Flexion deformity, left knee, M21.269 — Flexion deformity, unspecified knee, M21.271 — Flexion deformity, right ankle and toes, M21.272 — Flexion deformity, left ankle and toes, M21.279 — Flexion deformity, unspecified ankle and toes, M21.331 — Wrist drop, right wrist, +124 more

Same Index main term, other category

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

M20.01 — Mallet finger (finger, mallet finger), M20.02 — Boutonnière deformity (finger, boutonniere), M20.03 — Swan-neck deformity (finger, swan-neck), M20.09 — Other deformity of finger(s) (finger, specified NEC), M20.1 — Hallux valgus (acquired) (toe, hallux valgus), M20.2 — Hallux rigidus (toe, hallux rigidus), M20.3 — Hallux varus (acquired) (toe, hallux varus), M20.4 — Other hammer toe(s) (acquired) (toe, hammer toe), M20.5X — Other deformities of toe(s) (acquired) (toe, specified NEC), M20.6 — Acquired deformities of toe(s), unspecified (toe), M26.9 — Dentofacial anomaly, unspecified (jaw), M27.8 — Other specified diseases of jaws (palate, acquired), M62.89 — Other specified disorders of muscle (muscle), M95.0 — Acquired deformity of nose (nose), M95.2 — Other acquired deformity of head (head), M95.3 — Acquired deformity of neck (neck), M95.4 — Acquired deformity of chest and rib (rib), M95.5 — Acquired deformity of pelvis (ilium), M95.8 — Other specified acquired deformities of musculoskeletal system (trunk), M95.9 — Acquired deformity of musculoskeletal system, unspecified (bone NOS), +192 more

Contextual Map

Every relationship of M21.249 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 M21.249 with these 5 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

Referenced by Excludes2 notes

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 08 — Diseases and Disorders of the Musculoskeletal System and Connective Tissue[MDC crossing]: “Diseases and Disorders of the Musculoskeletal System and Connective Tissue — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 18,439 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027

Nearest codes (40)

Change history

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

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 FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v44 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

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "M21.249 — Flexion deformity, unspecified finger joints." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/m21.249-flexion-deformity-unspecified-finger-joints

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Flexion deformity, unspecified finger joints

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027, and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to M21.249 in its code family, with their registry titles.

View all codes in the M21 family