ICD-10 Code S46.191A: Other injury of shoulder muscle and tendon

Key Takeaways

ICD-10 Code S46.191A describes other injury of muscle, fascia and tendon at shoulder and upper arm level, other muscles, initial encounter.

S46.191A is a billable/specific ICD-10-CM code valid for HIPAA-covered claim submission as of FY2026 (effective October 1, 2025).

The 7th character A denotes initial encounter; sibling codes S46.191D (subsequent) and S46.191S (sequela) cover later care phases.

Pabau’s claims management software helps orthopedic, physical therapy, and sports medicine practices track encounter phases and submit accurate injury codes.

Shoulder and upper arm soft-tissue injuries generate a surprisingly high rate of coding errors. A claim submitted with the wrong 7th character or the wrong S46 sibling code can trigger a denial before a clinician even sees the remittance. ICD-10 Code S46.191A covers other injury of muscle, fascia and tendon at shoulder and upper arm level, other muscles, initial encounter, and it applies across orthopedics, physical therapy, sports medicine, and workers compensation settings. This reference covers billable status, the full 7th character set, code hierarchy, related codes, ICD-9 crosswalk, and documentation requirements.

The ICD-10-CM coding guidelines maintained by the Centers for Medicare and Medicaid Services (CMS) govern how injury codes in Chapter 19 (S00-T88) are applied, including the 7th character rules that distinguish active treatment from follow-up care. Getting this right matters: incorrect 7th character selection is one of the most cited reasons for injury-code denials in orthopedic and physical therapy billing. Practices managing HIPAA-compliant billing workflows need a reliable reference for every code in their typical encounter mix.

ICD-10 Code S46.191A: full description and billable status

ICD-10 Code S46.191A is a billable/specific ICD-10-CM code valid for submission on HIPAA-covered transactions. The 2026 edition became effective October 1, 2025, and it remains current for fiscal year 2026 claims. The full clinical description is: Other injury of muscle, fascia and tendon at shoulder and upper arm level, other muscles, initial encounter.

The term “other injury” in the descriptor is important. Within the S46 category, strains of shoulder muscles are coded under S46.01x, while S46.191A captures injuries to non-rotator-cuff muscles that do not meet the definition of a strain or sprain. Coders should verify the clinical notes confirm the injury type before selecting this code over a strain-specific sibling. The CDC/NCHS ICD-10-CM web tool provides the official tabular list for confirming current code descriptions and inclusion notes.

Understanding the 7th character in S46.191A: A, D, and S

The 7th character is where most S46.191x errors occur. Per the ICD-10-CM Official Guidelines for Coding and Reporting, every traumatic injury code in Chapter 19 requires a 7th character that identifies the encounter type. Three options apply to S46.191:

S46.191A: initial encounter (7th character A)

Use S46.191A when the patient is receiving active treatment for this shoulder injury. “Active treatment” includes the first evaluation, surgical intervention, application of immobilization, or the first physical therapy session directed at the injury itself. The number of visits does not determine whether A applies; the phase of care does.

• Emergency department visit for the acute injury
• Initial orthopedic evaluation with imaging review
• First physical therapy evaluation and plan of care establishment
• Surgical repair performed during active treatment phase

S46.191D: subsequent encounter

Switch to S46.191D once active treatment has transitioned to routine healing and recovery care. Follow-up visits for wound checks, range-of-motion monitoring, or continued physical therapy after the initial plan of care is underway all fall here. Coders commonly apply A too long, continuing it through weeks of follow-up PT when D became appropriate after the first session established the treatment plan. Practices using appointment and encounter tracking software can flag the phase transition automatically.

S46.191S: sequela

Sequela coding applies when the patient presents with a late effect of the original shoulder injury. Two codes are required: S46.191S plus the code for the nature of the sequela (for example, a chronic pain or range-of-motion limitation code). Sequela coding errors are rare for this injury type, but they occur when providers document a new complaint that traces directly to the prior shoulder incident.

Code hierarchy and parent codes for ICD-10 Code S46.191A

Understanding where S46.191A sits in the ICD-10-CM tabular list helps coders navigate to the correct code and verify there is no more specific option available. The WHO ICD-10 framework organises injury codes hierarchically from chapter down to the specific billable code. The hierarchy for ICD-10 Code S46.191A is:

Coders using the ICD-10-CM classification system to navigate Chapter 19 injury codes will recognise this hierarchy pattern across all musculoskeletal injury categories. The category S46 distinguishes between specific muscle groups: S46.0x covers the rotator cuff, S46.1x covers the biceps, and S46.19x captures all other muscles not classified under the rotator cuff or biceps groupings.

Approximate synonyms and clinical terminology for S46.191A

Providers and coders may encounter this injury documented under several clinical terms. None of these are exact synonyms, but they map to S46.191A when the injury involves muscle, fascia, or tendon at the shoulder or upper arm in a non-strain, non-sprain presentation:

• Other injury of muscle of shoulder
• Other injury of tendon at shoulder and upper arm level
• Other injury of fascia at shoulder level
• Contusion of muscle, shoulder region (non-strain classification)
• Blunt soft-tissue injury, upper arm musculature
• Overuse injury, shoulder soft tissue (non-rotator cuff, non-biceps)

The key clinical distinction is between a strain (coded under S46.01x for rotator cuff or S46.11x for biceps) and an “other injury” under S46.19x. When provider notes describe a muscle tear, laceration, or contusion without using strain or sprain terminology, S46.191A is typically the correct code if the injured structure is not the rotator cuff or biceps. Documentation that specifies the anatomical structure injured helps coders avoid unspecified sibling codes. Practices relying on clinical record documentation tools can prompt providers to capture this specificity at the point of care.

Related and sibling codes in the S46 category

Selecting the right code within S46 requires comparing S46.191A against its siblings. These codes share the same anatomical site but differ by injured structure or injury type. The table below focuses on initial-encounter (A suffix) codes for direct comparison:

The AAPC Codify ICD-10-CM lookup allows coders to browse the full S46 code tree alongside index references, which helps when the clinical note describes the injury in terms that don’t map cleanly to one code. For traumatic injury diagnosis codes across all Chapter 19 blocks, the same 7th character rules apply.

ICD-9-CM crosswalk: converting S46.191A

Legacy systems, research queries, and some state workers compensation reporting still reference ICD-9-CM codes. The approximate crosswalk for S46.191A maps to ICD-9-CM code 959.2 (Injury, other and unspecified, shoulder and upper arm). This is an approximate mapping, not an exact equivalent: ICD-9 959.2 is broader and covers a range of shoulder injuries that ICD-10-CM distinguishes with far greater specificity across the S40-S49 block.

For research or retrospective audits requiring ICD-9 conversion, use the PGM Billing ICD-9 to ICD-10 crosswalk tool, which references CMS General Equivalence Mappings (GEMs) files. Workers compensation payers that have not fully migrated to ICD-10 may still accept 959.2 on some legacy forms, but current HIPAA-covered transactions require the ICD-10-CM code. Review physiotherapy compliance requirements in your jurisdiction before using ICD-9 codes on any active claim.

Clinical documentation requirements for S46.191A

A claim supported by S46.191A must have documentation that justifies each component of the code. The provider note needs to support: the anatomical site (shoulder or upper arm), the structure involved (muscle, fascia, or tendon), the injury type (other than strain or sprain), the encounter type (initial, which means active treatment), and laterality if relevant to the claim.

• Anatomical specificity: note should identify shoulder or upper arm level; ideally names the specific muscle group (deltoid, teres major, coracobrachialis)
• Injury type: documentation must indicate an injury category other than strain/sprain; contusion, laceration, tear, or overuse injury without strain language all qualify
• Encounter type: chart must support that this visit constitutes active treatment, not routine follow-up
• Mechanism of injury: optional for code selection but required for workers comp and some casualty claims; document how the injury occurred
• Laterality: S46.191A is unspecified for laterality; if the payer or program requires laterality, verify whether a more specific sibling code exists

Good documentation at the point of care protects against payer audits and reduces query volumes from coders. Practices using claims management workflows can build documentation prompts into their intake and assessment templates to capture these elements before the claim is submitted. The injury and condition ICD-10 coding principles that apply to Chapter 19 codes require the same documentation discipline across all injury types, not just musculoskeletal.

Common billing scenarios: who uses ICD-10 Code S46.191A?

S46.191A appears across several specialties. The 7th character selection and pairing requirements vary by payer and care setting, which is where most billing differences arise.

Workers compensation billing deserves a specific note. State workers comp boards set their own billing rules, and some require additional external cause codes paired with S46.191A to document the mechanism and place of injury. Blanket statements about workers comp coverage cannot be made; always confirm with the applicable state board or payer. Physical therapy documentation systems that support ICD-10 encounter-phase tracking reduce the risk of carrying A through an entire course of PT treatment when D became appropriate after the first session.

Sports medicine practices benefit from workflow tools that connect the injury code to the specific encounter date and treatment phase. Sports medicine practice workflows that integrate scheduling with clinical records make it easier to identify when a patient has transitioned from active treatment to the follow-up phase, removing the guesswork from 7th character selection.

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Conclusion

Coding errors on S46.191A claims almost always come down to two issues: using the wrong 7th character after the initial treatment phase, or selecting an unspecified sibling when documentation supports a more specific code. Both problems trace to gaps between the clinical note and the coding workflow.

Practices that capture injury type, anatomical structure, and encounter phase at the point of documentation submit cleaner claims with fewer queries. Pabau’s practice management and billing software connects clinical documentation with claims submission so the encounter phase is never an afterthought. To see how Pabau handles injury code tracking across specialties, book a demo.

Continue your research

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Coding multiple injury types in a musculoskeletal practice? Physiotherapy clinic compliance requirements outlines documentation standards that support clean ICD-10 claims.

Want to streamline workers comp and commercial claims in one system? Claims management workflows shows how Pabau connects injury documentation to claim submission across payer types.

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