2026 ICD-10-CM Diagnosis Code S46.311AStrain of muscle, fascia and tendon of triceps, right arm, initial encounter
S46.311A is a billable ICD-10-CM diagnosis code for strain of muscle, fascia and tendon of triceps, right arm, 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 562 through 563, 963 through 965. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Sprains and strains, initial encounter.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Injury of muscle of right upper arm
- Injury of triceps brachii muscle
- Right triceps injury
- Right triceps tendon tear
- Rupture triceps tendon
- Strain of muscle of right upper arm
- Strain of muscle of upper arm
- Strain of right triceps brachii muscle
- Strain of right triceps brachii muscle and/or tendon
- Strain of triceps brachii muscle
- Strain of triceps brachii muscle and/or tendon
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.
Patient EducationClinical
Arm Injuries and Disorders
Of the 206 bones in your body, three of them are in your arm: the humerus, radius, and ulna. Your arms are also made up of muscles, joints, tendons, and other connective tissue. Injuries to any of these parts of the arm can occur during sports, a fall, or an accident.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert S46.311A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S46.311AOverview
Is S46.311A (Strain of muscle, fascia and tendon of triceps, right arm) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report strain of muscle, fascia and tendon of triceps, right arm, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in S46.311A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for strain of muscle, fascia and tendon of triceps, right arm, such as an emergency visit or first evaluation.
What MS-DRG does S46.311A group to?
When strain of muscle, fascia and tendon of triceps, right arm, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 562, 563, 963, 964, 965, with relative weights from 0.8955 to 2.7338 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of S46.311A?
Under the General Equivalence Mappings, strain of muscle, fascia and tendon of triceps, right arm, initial encounter converts to ICD-9-CM 840.8 (sprain shoulder/arm NEC). 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.
