2026 ICD-10-CM Diagnosis Code S46.001AUnspecified injury of muscle(s) and tendon(s) of the rotator cuff of right shoulder, initial encounter

ICD-10-CM Codes›S00–T88›S40-S49›S46

ICD-10-CM S46.001A
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S46.001A is a billable ICD-10-CM diagnosis code for unspecified injury of muscle(s) and tendon(s) of the rotator cuff of right shoulder, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 913 through 914, 963 through 965. Coders also document this condition as injury of right rotator cuff. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Injury to nerves, muscles and tendons, initial encounter.

Code Identity

ICD-10-CM Code
S46.001A
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified injury of muscle(s) and tendon(s) of the rotator cuff of right shoulder, initial encounter
Short Description
Unsp inj musc/tend the rotator cuff of r shoulder, init
Parent Code
S46.001
Unspecified injury of muscle(s) and tendon(s) of the rotator cuff of right shoulder

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS40-S49Injuries to the shoulder and upper arm
CategoryS46Injury of muscle, fascia and tendon at shoulder and upper arm level
This CodeS46.001AUnspecified injury of muscle(s) and tendon(s) of the rotator cuff of right shoulder, initial encounter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Injury of right rotator cuff

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Injury of muscle, fascia and tendon at shoulder and upper arm level (S46). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INJ025
Injury to nerves, muscles and tendons, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Rotator Cuff Injuries

Your rotator cuff is part of your shoulder joint. It's a group of muscles and tendons that holds the top part of your upper arm bone firmly in your shoulder socket. The rotator cuff keeps your shoulder stable when you move your arm in any direction.

The full article covers:

  • What is a rotator cuff?
  • What are rotator cuff injuries?
  • Who is more likely to develop a rotator cuff injury?
  • What are the symptoms of rotator cuff injuries?
  • How are rotator cuff injuries diagnosed?
  • What are the treatments for rotator cuff injuries?
  • When should I see a health care provider for shoulder pain?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert S46.001A to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
959.2 Shldr/upper arm inj NOS
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About S46.001AOverview

Is S46.001A a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unspecified injury of muscle(s) and tendon(s) of the rotator cuff of right shoulder, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in S46.001A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for unspecified injury of muscle(s) and tendon(s) of the rotator cuff of right shoulder, such as an emergency visit or first evaluation.

What MS-DRG does S46.001A group to?

When unspecified injury of muscle(s) and tendon(s) of the rotator cuff of right shoulder, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 913, 914, 963, 964, 965, with relative weights from 0.8855 to 2.7338 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of S46.001A?

Under the General Equivalence Mappings, unspecified injury of muscle(s) and tendon(s) of the rotator cuff of right shoulder, initial encounter converts to ICD-9-CM 959.2 (shldr/upper arm inj NOS). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.