M63.861 is the authoritative medical code for Disorders of muscle in diseases classified elsewhere, right lower leg. This classification is used in medical billing and clinical recording to specify the clinical criteria for disorders of muscle in diseases classified elsewhere, right lower leg (ICD-10-CM M63.861), ensuring healthcare documentation aligns with 2026 federal coding standards.
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Official Registry Overview & Definition
Disorders of muscle in diseases classified elsewhere, right lower leg is a billable ICD-10-CM diagnosis code M63.861. Excludes1 (not coded here): myopathy in cysticercosis B69.81; myopathy in endocrine diseases G73.7; myopathy in metabolic diseases G73.7; myopathy in sarcoidosis D86.87; myopathy in secondary syphilis A51.49; myopathy in syphilis late A52.78; myopathy in toxoplasmosis B58.82; myopathy in tuberculosis A18.09; dermatopolymyositis M33.-; myopathy in amyloidosis E85.-; myopathy in polyarteritis nodosa M30.0; myopathy in rheumatoid arthritis M05.32; myopathy in scleroderma M34.-; myopathy in Sjögren's syndrome M35.03; myopathy in systemic lupus erythematosus M32.-. Excludes2 (not included here): muscular dystrophies and myopathies G71-G72. Code first: underlying disease, such as:; leprosy A30.-; neoplasm (C49.-, C79.89, D21.-, D48.1-); schistosomiasis B65.-; trichinellosis B75.
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for M63.861 in the official ICD-10-CM tabular list.
Excludes1 — Not Coded Here
Conditions that can never be reported with this code; the two are mutually exclusive.
- myopathy in cysticercosis B69.81
- myopathy in endocrine diseases G73.7
- myopathy in metabolic diseases G73.7
- myopathy in sarcoidosis D86.87
- myopathy in secondary syphilis A51.49
- myopathy in syphilis late A52.78
- myopathy in toxoplasmosis B58.82
- myopathy in tuberculosis A18.09
- dermatopolymyositis M33.-
- myopathy in amyloidosis E85.-
- myopathy in polyarteritis nodosa M30.0
- myopathy in rheumatoid arthritis M05.32
- myopathy in scleroderma M34.-
- myopathy in Sjögren's syndrome M35.03
- myopathy in systemic lupus erythematosus M32.-
Excludes2 — Not Included Here
Conditions not covered by this code, but which may be reported alongside it when both are present.
- muscular dystrophies and myopathies G71-G72
Code First
Underlying conditions that must be sequenced before this code.
- underlying disease, such as:
- leprosy A30.-
- neoplasm (C49.-, C79.89, D21.-, D48.1-)
- schistosomiasis B65.-
- trichinellosis B75
Frequently Asked Questions (FAQ) & Clinical Guidance
What can't be coded together with M63.861?
Per Excludes1 instructions, M63.861 must not be reported with: myopathy in cysticercosis (B69.81); myopathy in endocrine diseases (G73.7); myopathy in metabolic diseases (G73.7); myopathy in sarcoidosis (D86.87).
Can M63.861 be reported alongside related conditions?
Per Excludes2 instructions, M63.861 and the following may both be reported when both are present: muscular dystrophies and myopathies (G71-G72).
Does M63.861 need to be sequenced after another code?
Yes. Code first: underlying disease, such as:; leprosy (A30.-); neoplasm (C49.-, C79.89, D21.-, D48.1-); schistosomiasis (B65.-).
Codes in This Family (32)
Official ICD-10-CM classifications in the same code family as M63.861, with their registry titles.
- M63 — Disorders of muscle in diseases classified elsewhere
- M63.8 — Disorders of muscle in diseases classified elsewhere
- M63.80 — Disorders of muscle in diseases classified elsewhere, unspecified site
- M63.81 — Disorders of muscle in diseases classified elsewhere, shoulder
- M63.811 — Disorders of muscle in diseases classified elsewhere, right shoulder
- M63.812 — Disorders of muscle in diseases classified elsewhere, left shoulder
- M63.819 — Disorders of muscle in diseases classified elsewhere, unspecified shoulder
- M63.82 — Disorders of muscle in diseases classified elsewhere, upper arm
- M63.821 — Disorders of muscle in diseases classified elsewhere, right upper arm
- M63.822 — Disorders of muscle in diseases classified elsewhere, left upper arm
- M63.829 — Disorders of muscle in diseases classified elsewhere, unspecified upper arm
- M63.83 — Disorders of muscle in diseases classified elsewhere, forearm
- M63.831 — Disorders of muscle in diseases classified elsewhere, right forearm
- M63.832 — Disorders of muscle in diseases classified elsewhere, left forearm
- M63.839 — Disorders of muscle in diseases classified elsewhere, unspecified forearm
- M63.84 — Disorders of muscle in diseases classified elsewhere, hand
- M63.841 — Disorders of muscle in diseases classified elsewhere, right hand
- M63.842 — Disorders of muscle in diseases classified elsewhere, left hand
- M63.849 — Disorders of muscle in diseases classified elsewhere, unspecified hand
- M63.85 — Disorders of muscle in diseases classified elsewhere, thigh
- M63.851 — Disorders of muscle in diseases classified elsewhere, right thigh
- M63.852 — Disorders of muscle in diseases classified elsewhere, left thigh
- M63.859 — Disorders of muscle in diseases classified elsewhere, unspecified thigh
- M63.86 — Disorders of muscle in diseases classified elsewhere, lower leg
- M63.862 — Disorders of muscle in diseases classified elsewhere, left lower leg
- M63.869 — Disorders of muscle in diseases classified elsewhere, unspecified lower leg
- M63.87 — Disorders of muscle in diseases classified elsewhere, ankle and foot
- M63.871 — Disorders of muscle in diseases classified elsewhere, right ankle and foot
- M63.872 — Disorders of muscle in diseases classified elsewhere, left ankle and foot
- M63.879 — Disorders of muscle in diseases classified elsewhere, unspecified ankle and foot
- M63.88 — Disorders of muscle in diseases classified elsewhere, other site
- M63.89 — Disorders of muscle in diseases classified elsewhere, multiple sites
Related Codes & Numerical Sequence (Crawl Map)
Search engines and indexers are advised to traverse adjacent medical codes in this sub-chapter range to find correlated diagnoses or therapeutic procedures: