S23.9XXS ICD-10-CM Code: Sprain of unspecified parts of thorax, sequela

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for S23.9XXS in the official ICD-10-CM tabular list, quoted as published.

Notes without a marker are published on S23.9XXS itself; “inherited from” names the category or block whose note applies here.

7th Character Guide

"The appropriate 7th character is to be added to each code from category S23"

• A — initial encounter
• D — subsequent encounter
• S — sequela (this page’s code)

How the encounter character is assigned. “Initial encounter” means the patient is receiving active treatment for the condition — it is not limited to the first visit, and a different or new provider giving active treatment still assigns it. “Subsequent encounter” covers care during the healing or recovery phase after active treatment. “Sequela” is for complications or conditions that arise as a direct result of the original condition.

ICD-10-CM Official Guidelines for Coding and Reporting, Section I.C.19.a (paraphrased by MedCoder).

Variant codes in this family

S23.9XXA, S23.9XXD, S23.9XXS

Character meanings are CMS's official 7th-character extensions for this family, as carried in each variant code's official description; variant codes are registry rows. The explanation of how the encounter character is assigned is MedCoder editorial, distinct from the official content above it.

Do Not Confuse With

Codes named in S23.9XXS's own official notes, or sharing its encounter family, with what separates them. Each links to the full comparison.

• S23.9XXA— Encounter relationship (Review)

  Same underlying diagnosis, different encounter phase.

  The same diagnosis at a different phase of care; one encounter takes one 7th character.

  Full comparison: S23.9XXS vs S23.9XXA →

• S23.9XXD— Encounter relationship (Review)

  Same underlying diagnosis, different encounter phase.

  The same diagnosis at a different phase of care; one encounter takes one 7th character.

  Full comparison: S23.9XXS vs S23.9XXD →

• S43.2— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

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

  Full comparison: S23.9XXS vs S43.2 →

• S43.6— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

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

  Full comparison: S23.9XXS vs S43.6 →

• S29.01— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

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

  Full comparison: S23.9XXS vs S29.01 →

• T20— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

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

  Full comparison: S23.9XXS vs T20 →

Relationships are read from this code's own official notes and its encounter family; the wording of each distinction is MedCoder editorial. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

1. A 7th character applies in this family. Confirm the documented encounter matches the character assigned. See the official 7th-character definitions and this code’s variants
2. 1 Code Also note — a second code may apply; the guidelines leave its sequencing to the circumstances of the encounter. See the Code Also notes
3. 13 Excludes2 entries — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

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

MS-DRG Grouper Relationships (FY2026)

Not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity.

Potential MS-DRG participation — not a DRG assignment.

Named in the grouper logic of 2 MS-DRGs: DRG 562 (MDC 08), DRG 563 (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):INJ073 — Injury, sequela (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 injury, other encounter phase

Same injury, coded at a different phase of treatment via the 7th character.

S23.9XXA — Sprain of unspecified parts of thorax, initial encounterCompare S23.9XXS vs S23.9XXA →, S23.9XXD — Sprain of unspecified parts of thorax, subsequent encounter

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Injury, sequela).

+7578 more

Contextual Map

Every relationship of S23.9XXS 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.

Hierarchy

• S00-T88 — Chapter 19: Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) (S00-T88)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S20-S29 — Injuries to the thorax[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Clinical classification (CCSR)

• INJ073 — Injury, sequela[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

• DRG 562 — FRACTURE, SPRAIN, STRAIN AND DISLOCATION EXCEPT FEMUR, HIP, PELVIS AND THIGH WITH MCC[MS-DRG]: “FRACTURE, SPRAIN, STRAIN AND DISLOCATION EXCEPT FEMUR, HIP, PELVIS AND THIGH WITH MCC (MDC 08)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 563 — FRACTURE, SPRAIN, STRAIN AND DISLOCATION EXCEPT FEMUR, HIP, PELVIS AND THIGH WITHOUT MCC[MS-DRG]: “FRACTURE, SPRAIN, STRAIN AND DISLOCATION EXCEPT FEMUR, HIP, PELVIS AND THIGH WITHOUT MCC (MDC 08)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

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. 18,508 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Nearest codes (40)

• S23 — Dislocation and sprain of joints and ligaments of thorax[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S23.20XA — Dislocation of unspecified part of thorax, initial encounter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S23.20XD — Dislocation of unspecified part of thorax, subsequent encounter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S23.20XS — Dislocation of unspecified part of thorax, sequela[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S23.29 — Dislocation of other parts of thorax[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S23.29XA — Dislocation of other parts of thorax, initial encounter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S23.29XD — Dislocation of other parts of thorax, subsequent encounter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S23.29XS — Dislocation of other parts of thorax, sequela[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 32 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

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 — v43 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 S23.9XXS in its code family, with their registry titles.

• S23.429 — Unspecified sprain of sternum
• S23.429A — Unspecified sprain of sternum, initial encounter
• S23.429D — Unspecified sprain of sternum, subsequent encounter
• S23.429S — Unspecified sprain of sternum, sequela
• S23.8 — Sprain of other specified parts of thorax
• S23.8XXA — Sprain of other specified parts of thorax, initial encounter
• S23.8XXD — Sprain of other specified parts of thorax, subsequent encounter
• S23.8XXS — Sprain of other specified parts of thorax, sequela
• S23.9 — Sprain of unspecified parts of thorax
• S23.9XXA — Sprain of unspecified parts of thorax, initial encounter

View all codes in the S23 family