2026 ICD-10-CM Diagnosis Code M63.862

Disorders of muscle in diseases classified elsewhere, left lower leg

ICD-10-CM Code:
M63.862
ICD-10 Code for:
Disorders of muscle in diseases classd elswhr, l low leg
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Not chronic
Code Navigator:

M63.862 is a billable diagnosis code used to specify a medical diagnosis of disorders of muscle in diseases classified elsewhere, left lower leg. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2025 through September 30, 2026.

Code Classification

  • Diseases of the musculoskeletal system and connective tissue
    M00–M99
    • Disorders of muscles
      M60-M63
      • Disorders of muscle in diseases classified elsewhere
        M63

Clinical Classification

Clinical Classifications group individual ICD-10-CM diagnosis codes into broader, clinically meaningful categories. These categories help simplify complex data by organizing related conditions under common clinical themes.

They are especially useful for data analysis, reporting, and clinical decision-making. Even when diagnosis codes differ, similar conditions can be grouped together based on their clinical relevance. Each category is assigned a unique CCSR code that represents a specific clinical concept, often tied to a body system or medical specialty.

Muscle disorders

CCSR Code: MUS026

Inpatient Default: X - Not applicable.

Outpatient Default: X - Not applicable.

Code Edits

The Medicare Code Editor (MCE) detects errors and inconsistencies in ICD-10-CM diagnosis coding that can affect Medicare claim validity. These Medicare code edits help medical coders and billing professionals determine when a diagnosis code is not appropriate as a principal diagnosis, does not meet coverage criteria. Use this list to verify whether a code is valid for Medicare billing and to avoid claim rejections or denials due to diagnosis coding issues.

Manifestation diagnoses

Manifestation codes describe the manifestation of an underlying disease, not the disease itself, and therefore should not be used as a principal diagnosis.

Convert M63.862 to ICD-9-CM

Below are the ICD-9 codes that most closely match this ICD-10 code, based on the General Equivalence Mappings (GEMs). This ICD-10 to ICD-9 crosswalk tool is helpful for coders who need to reference legacy diagnosis codes for audits, historical claims, or approximate code comparisons.

Muscle/ligament dis NOS

ICD-9-CM: 728.9

Approximate Flag - The approximate mapping means this ICD-10 code does not have an exact ICD-9 equivalent. The matched code is the closest available option, but it may not fully capture the original diagnosis or clinical intent.

Patient Education


Muscle Disorders

Your muscles help you move and help your body work. Different types of muscles have different jobs. There are many problems that can affect muscles. Muscle disorders can cause weakness, pain or even paralysis.

Causes of muscle disorders include:

  • Injury or overuse, such as sprains or strains, cramps or tendinitis
  • A genetic disorder, such as muscular dystrophy
  • Some cancers
  • Inflammation, such as myositis
  • Diseases of nerves that affect muscles
  • Infections
  • Certain medicines

Sometimes the cause of muscle disorders is unknown.


[Learn More in MedlinePlus]

Code History

  • FY 2026 - No Change, effective from 10/1/2025 through 9/30/2026
  • FY 2025 - No Change, effective from 10/1/2024 through 9/30/2025
  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.

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.