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ICD-10/S44.31XA

S44.31XA ICD-10-CM Code: Injury of axillary nerve, right arm, initial encounter

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

Inpatient Payment Groups (MS-DRG)

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0, Appendix B.

  • MS-DRG 073 — CRANIAL AND PERIPHERAL NERVE DISORDERS WITH MCC (MDC 01)
  • MS-DRG 074 — CRANIAL AND PERIPHERAL NERVE DISORDERS WITHOUT MCC (MDC 01)
  • MS-DRG 963 — OTHER MULTIPLE SIGNIFICANT TRAUMA WITH MCC (MDC 24)
  • MS-DRG 964 — OTHER MULTIPLE SIGNIFICANT TRAUMA WITH CC (MDC 24)
  • MS-DRG 965 — OTHER MULTIPLE SIGNIFICANT TRAUMA WITHOUT CC/MCC (MDC 24)

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.

Official Registry Overview & Definition

Injury of axillary nerve, right arm, initial encounter is a billable ICD-10-CM diagnosis code (S44.31A).

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for S44.31XA in the official ICD-10-CM tabular list.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • injuries of axilla
  • injuries of scapular region

Excludes2 — Not Included Here

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

Code Also

Additional codes that may be required to fully describe the encounter.

  • any associated open wound (S41.-)

Change history

No changes recorded for this code — unchanged since the FY2016 baseline of the change ledger.

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.

Contextual Map

Every relationship of S44.31XA 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]
  • S40-S49 — Injuries to the shoulder and upper arm [Hierarchy]

Clinical classification (CCSR)

  • INJ025 — Injury to nerves, muscles and tendons, initial encounter [CCSR]

Potential MS-DRG

  • DRG 073 — CRANIAL AND PERIPHERAL NERVE DISORDERS WITH MCC [MS-DRG]: “CRANIAL AND PERIPHERAL NERVE DISORDERS WITH MCC (MDC 01)”
  • DRG 074 — CRANIAL AND PERIPHERAL NERVE DISORDERS WITHOUT MCC [MS-DRG]: “CRANIAL AND PERIPHERAL NERVE DISORDERS WITHOUT MCC (MDC 01)”
  • DRG 963 — OTHER MULTIPLE SIGNIFICANT TRAUMA WITH MCC [MS-DRG]: “OTHER MULTIPLE SIGNIFICANT TRAUMA WITH MCC (MDC 24)”
  • DRG 964 — OTHER MULTIPLE SIGNIFICANT TRAUMA WITH CC [MS-DRG]: “OTHER MULTIPLE SIGNIFICANT TRAUMA WITH CC (MDC 24)”
  • DRG 965 — OTHER MULTIPLE SIGNIFICANT TRAUMA WITHOUT CC/MCC [MS-DRG]: “OTHER MULTIPLE SIGNIFICANT TRAUMA WITHOUT CC/MCC (MDC 24)”

MDC crossing · procedures (31849)

  • MDC 01 — Diseases and Disorders of the Nervous System [MDC crossing]: “Diseases and Disorders of the Nervous System — 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.”
  • MDC 24 — Multiple Significant Trauma [MDC crossing]: “Multiple Significant Trauma — 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.”
  • 0016070 — Bypass Cerebral Ventricle to Nasopharynx with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Nasopharynx with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • 0016071 — Bypass Cerebral Ventricle to Mastoid Sinus with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Mastoid Sinus with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • 0016072 — Bypass Cerebral Ventricle to Atrium with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Atrium with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • 0016073 — Bypass Cerebral Ventricle to Blood Vessel with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Blood Vessel with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • 0016074 — Bypass Cerebral Ventricle to Pleural Cavity with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Pleural Cavity with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • and 31844 more

Nearest codes (40)

  • S44 — Injury of nerves at shoulder and upper arm level [Sibling]
  • S44.12XS — Injury of median nerve at upper arm level, left arm, sequela [Sibling]
  • S44.2 — Injury of radial nerve at upper arm level [Sibling]
  • S44.20 — Injury of radial nerve at upper arm level, unspecified arm [Sibling]
  • S44.20XA — Injury of radial nerve at upper arm level, unspecified arm, initial encounter [Sibling]
  • S44.20XD — Injury of radial nerve at upper arm level, unspecified arm, subsequent encounter [Sibling]
  • S44.20XS — Injury of radial nerve at upper arm level, unspecified arm, sequela [Sibling]
  • S44.21 — Injury of radial nerve at upper arm level, right arm [Sibling]
  • and 32 more

Relationships & Classification

Clinical classification (AHRQ CCSR):INJ025 — Injury to nerves, muscles and tendons, initial encounter (default).

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

Potential MS-DRG Relationships (FY2026)

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

Named in the grouper logic of 5 MS-DRGs: DRG 073 (MDC 01), DRG 074 (MDC 01), DRG 963 (MDC 24), DRG 964 (MDC 24), DRG 965 (MDC 24).

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

Frequently Asked Questions (FAQ) & Clinical Guidance

Does S44.31XA require a 7th character?

Yes. The appropriate 7th character is to be added to each code from category S44.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to S44.31XA in its code family, with their registry titles.

  • S44.30 — Injury of axillary nerve, unspecified arm
  • S44.30XA — Injury of axillary nerve, unspecified arm, initial encounter
  • S44.30XD — Injury of axillary nerve, unspecified arm, subsequent encounter
  • S44.30XS — Injury of axillary nerve, unspecified arm, sequela
  • S44.31 — Injury of axillary nerve, right arm
  • S44.31XD — Injury of axillary nerve, right arm, subsequent encounter
  • S44.31XS — Injury of axillary nerve, right arm, sequela
  • S44.32 — Injury of axillary nerve, left arm
  • S44.32XA — Injury of axillary nerve, left arm, initial encounter
  • S44.32XD — Injury of axillary nerve, left arm, subsequent encounter

View all codes in the S44 family