M79.A21 Nontraumatic compartment syndrome of right lower extremity

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applies from M79 Other and unspecified soft tissue disorders, not elsewhere classified

Excludes1 (never code together)

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

Applies from M79.A Nontraumatic compartment syndrome

Excludes1 (never code together)

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

Code first

• , if applicable, associated postprocedural complication

Applies from M79.A2 Nontraumatic compartment syndrome of lower extremity

Applicable to

• Nontraumatic compartment syndrome of hip, buttock, thigh, leg, foot, and toes

MS-DRG index

Defines the logic of DRG(s) 557-558 in MDC 08.

Approximate ICD-9-CM (GEMs)

• 729.72 Nontraumatic compartment syndrome of lower extremity (approximate)

Code annotations containing back-references to M79.A21

Back-references to M79.A

• Type 1 Excludes: M62.2 Nontraumatic ischemic infarction of muscle ("nontraumatic compartment syndrome (M79.A-)")
• Type 1 Excludes: T79.A Traumatic compartment syndrome ("nontraumatic compartment syndrome (M79.A-)")

Nearby codes

• M79.A1 Nontraumatic compartment syndrome of upper extremity
• M79.A11 Nontraumatic compartment syndrome of right upper extremity
• M79.A12 Nontraumatic compartment syndrome of left upper extremity
• M79.A19 Nontraumatic compartment syndrome of unspecified upper extremity
• M79.A2 Nontraumatic compartment syndrome of lower extremity
• M79.A21 Nontraumatic compartment syndrome of right lower extremity (this code)
• M79.A22 Nontraumatic compartment syndrome of left lower extremity
• M79.A29 Nontraumatic compartment syndrome of unspecified lower extremity
• M79.A3 Nontraumatic compartment syndrome of abdomen
• M79.A9 Nontraumatic compartment syndrome of other sites
• M79.8 Other specified soft tissue disorders