M79.A21

✓ Billable

Nontraumatic compartment syndrome of right lower extremity

Diseases of the musculoskeletal system and connective tissue (M00-M99)

Check This Code

❌ Excludes1

inherited

Rules inherited from parent codes in the hierarchy.

M79.A

• compartment syndrome NOS (T79.A-)
• fibromyalgia (M79.7)
• nontraumatic ischemic infarction of muscle (M62.2-)
• traumatic compartment syndrome (T79.A-)

M79

• psychogenic rheumatism (F45.8)
• soft tissue pain, psychogenic (F45.41)

📋 Code Instructions

inherited

M79.A

• Code first: , if applicable, associated postprocedural complication

Clinical Description

ICD-10-CM code M79.A21 represents nontraumatic compartment syndrome of right lower extremity. This code falls under the Diseases of the musculoskeletal system and connective tissue (M00-M99) classification. It is a billable/specific code valid for HIPAA-covered transactions as of October 1, 2025 (FY2026). This code can be used to indicate a diagnosis for reimbursement purposes on insurance claims.

This is a 7-character code at the 6th level of specificity. This is the most specific code available in this subcategory. Coders should note that M79.A21 has 6 Excludes1 restriction(s) — codes that cannot be reported together on the same claim.

Frequently Asked Questions

What is ICD-10 code M79.A21?

ICD-10-CM code M79.A21 is "Nontraumatic compartment syndrome of right lower extremity". It belongs to the category: Diseases of the musculoskeletal system and connective tissue (M00-M99).

Is M79.A21 a billable ICD-10 code?

Yes, M79.A21 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.

What codes are excluded with M79.A21?

M79.A21 has 6 Excludes1 rule(s). These codes are mutually exclusive and cannot be coded together on the same claim.

Related Codes in M79.A2

Other codes in the same category that may be relevant for differential coding:

M79.A22Nontraumatic compartment syndrome of left lower extremity M79.A29Nontraumatic compartment syndrome of unspecified lower extremity

🧪 Validate Combinations

Add M79.A21 to the Excludes Checker to validate against your full code list.

Open in Checker →

Code Information

CodeM79.A21

BillableYes

ParentM79.A2

CategoryDiseases of the musculoskeletal system and connective tissue (M00-M99)

Excludes16 rule(s)

Excludes20 note(s)

Data Source

CMS ICD-10-CM 2026 Tabular List

Updated October 1, 2025 (FY2026)