ICD-10-CM category
M20: Acquired deformities of fingers and toes
Codes under M20 (Acquired deformities of fingers and toes). A ✓ marks a billable (fully specified) code; category codes without a ✓ are not billable on their own.
| Code | Description | Billable |
|---|---|---|
| M20.0 | Deformity of finger(s) | — |
| M20.0 | Deformity of finger(s) | — |
| M20.00 | Unspecified deformity of finger(s) | — |
| M20.00 | Unspecified deformity of finger(s) | — |
| M20.001 | Unspecified deformity of right finger(s) | ✓ |
| M20.001 | Unspecified deformity of right finger(s) | ✓ |
| M20.01 | Mallet finger | — |
| M20.01 | Mallet finger | — |
| M20.1 | Hallux valgus (acquired) | — |
| M20.1 | Hallux valgus (acquired) | — |
| M20.002 | Unspecified deformity of left finger(s) | ✓ |
| M20.002 | Unspecified deformity of left finger(s) | ✓ |
| M20.02 | Boutonniere deformity | — |
| M20.02 | Boutonniere deformity | — |
| M20.2 | Hallux rigidus | — |
| M20.2 | Hallux rigidus | — |
| M20.03 | Swan-neck deformity | — |
| M20.03 | Swan-neck deformity | — |
| M20.3 | Hallux varus (acquired) | — |
| M20.3 | Hallux varus (acquired) | — |
| M20.4 | Other hammer toe(s) (acquired) | — |
| M20.4 | Other hammer toe(s) (acquired) | — |
| M20.5 | Other deformities of toe(s) (acquired) | — |
| M20.5 | Other deformities of toe(s) (acquired) | — |
| M20.5X | Other deformities of toe(s) (acquired) | — |
| M20.5X | Other deformities of toe(s) (acquired) | — |
| M20.5X1 | Other deformities of toe(s) (acquired), right foot | ✓ |
| M20.5X1 | Other deformities of toe(s) (acquired), right foot | ✓ |
| M20.5X2 | Other deformities of toe(s) (acquired), left foot | ✓ |
| M20.5X2 | Other deformities of toe(s) (acquired), left foot | ✓ |
| M20.5X9 | Other deformities of toe(s) (acquired), unspecified foot | ✓ |
| M20.5X9 | Other deformities of toe(s) (acquired), unspecified foot | ✓ |
| M20.6 | Acquired deformities of toe(s), unspecified | — |
| M20.6 | Acquired deformities of toe(s), unspecified | — |
| M20.009 | Unspecified deformity of unspecified finger(s) | ✓ |
| M20.009 | Unspecified deformity of unspecified finger(s) | ✓ |
| M20.09 | Other deformity of finger(s) | — |
| M20.09 | Other deformity of finger(s) | — |
| M20.10 | Hallux valgus (acquired), unspecified foot | ✓ |
| M20.10 | Hallux valgus (acquired), unspecified foot | ✓ |
| M20.011 | Mallet finger of right finger(s) | ✓ |
| M20.011 | Mallet finger of right finger(s) | ✓ |
| M20.11 | Hallux valgus (acquired), right foot | ✓ |
| M20.11 | Hallux valgus (acquired), right foot | ✓ |
| M20.012 | Mallet finger of left finger(s) | ✓ |
| M20.012 | Mallet finger of left finger(s) | ✓ |
| M20.12 | Hallux valgus (acquired), left foot | ✓ |
| M20.12 | Hallux valgus (acquired), left foot | ✓ |
| M20.019 | Mallet finger of unspecified finger(s) | ✓ |
| M20.019 | Mallet finger of unspecified finger(s) | ✓ |
| M20.20 | Hallux rigidus, unspecified foot | ✓ |
| M20.20 | Hallux rigidus, unspecified foot | ✓ |
| M20.021 | Boutonniere deformity of right finger(s) | ✓ |
| M20.021 | Boutonniere deformity of right finger(s) | ✓ |
| M20.21 | Hallux rigidus, right foot | ✓ |
| M20.21 | Hallux rigidus, right foot | ✓ |
| M20.022 | Boutonniere deformity of left finger(s) | ✓ |
| M20.022 | Boutonniere deformity of left finger(s) | ✓ |
| M20.22 | Hallux rigidus, left foot | ✓ |
| M20.22 | Hallux rigidus, left foot | ✓ |
| M20.029 | Boutonniere deformity of unspecified finger(s) | ✓ |
| M20.029 | Boutonniere deformity of unspecified finger(s) | ✓ |
| M20.30 | Hallux varus (acquired), unspecified foot | ✓ |
| M20.30 | Hallux varus (acquired), unspecified foot | ✓ |
| M20.031 | Swan-neck deformity of right finger(s) | ✓ |
| M20.031 | Swan-neck deformity of right finger(s) | ✓ |
| M20.31 | Hallux varus (acquired), right foot | ✓ |
| M20.31 | Hallux varus (acquired), right foot | ✓ |
| M20.032 | Swan-neck deformity of left finger(s) | ✓ |
| M20.032 | Swan-neck deformity of left finger(s) | ✓ |
| M20.32 | Hallux varus (acquired), left foot | ✓ |
| M20.32 | Hallux varus (acquired), left foot | ✓ |
| M20.039 | Swan-neck deformity of unspecified finger(s) | ✓ |
| M20.039 | Swan-neck deformity of unspecified finger(s) | ✓ |
| M20.40 | Other hammer toe(s) (acquired), unspecified foot | ✓ |
| M20.40 | Other hammer toe(s) (acquired), unspecified foot | ✓ |
| M20.41 | Other hammer toe(s) (acquired), right foot | ✓ |
| M20.41 | Other hammer toe(s) (acquired), right foot | ✓ |
| M20.42 | Other hammer toe(s) (acquired), left foot | ✓ |
| M20.42 | Other hammer toe(s) (acquired), left foot | ✓ |
| M20.60 | Acquired deformities of toe(s), unspecified, unspecified foot | ✓ |
| M20.60 | Acquired deformities of toe(s), unspecified, unspecified foot | ✓ |
| M20.61 | Acquired deformities of toe(s), unspecified, right foot | ✓ |
| M20.61 | Acquired deformities of toe(s), unspecified, right foot | ✓ |
| M20.62 | Acquired deformities of toe(s), unspecified, left foot | ✓ |
| M20.62 | Acquired deformities of toe(s), unspecified, left foot | ✓ |
| M20.091 | Other deformity of right finger(s) | ✓ |
| M20.091 | Other deformity of right finger(s) | ✓ |
| M20.092 | Other deformity of left finger(s) | ✓ |
| M20.092 | Other deformity of left finger(s) | ✓ |
| M20.099 | Other deformity of finger(s), unspecified finger(s) | ✓ |
| M20.099 | Other deformity of finger(s), unspecified finger(s) | ✓ |
Frequently asked questions
What is ICD-10-CM code M20?
M20 is an ICD-10-CM category covering Acquired deformities of fingers and toes. It contains 92 more specific diagnosis codes, 66 of which are billable.
Is M20 a billable code?
No — M20 is a category header and isn't billable on its own. Code to the highest level of specificity using one of its subcodes (for example M20.0 — Deformity of finger(s)). 66 of the 92 codes under M20 are billable.
What codes fall under M20?
M20 includes M20.0, M20.0, M20.00, M20.00, M20.001, plus 87 more. See the full list with descriptions and billable status above.
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Informational only, not coding or medical advice. Verify against the official ICD-10-CM (FY2026) and your payer's guidelines.
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