M21.931 (Unspecified acquired deformity of right forearm) compared with M21.939 (Unspecified acquired deformity of unspecified forearm), from the official CMS tabular data. M21.931 and M21.939 code the same condition on opposite sides.
Same condition; these differ only in which side is documented.
These codes share a category and title and differ only in the side affected. The documentation decides which applies, and a bilateral code is reported only where the code set provides one.
Source: ICD-10-CM tabular list (laterality variant derived from the code title)
Same condition, opposite side. M21.931 and M21.939 name the same condition on opposite sides of the body.
Same category and title, differing only in which side is affected — the documentation decides which one applies, and a bilateral code is reported only where the code set provides one.
| M21.931Unspecified acquired deformity of right forearm | M21.939Unspecified acquired deformity of unspecified forearm | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) | M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) |
| Definition | Unspecified acquired deformity of right forearm is a billable ICD-10-CM diagnosis code (M21.931). | Unspecified acquired deformity of unspecified forearm is a billable ICD-10-CM diagnosis code (M21.939). |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources