M61.551 (Other ossification of muscle, right thigh) compared with M61.559 (Other ossification of muscle, unspecified thigh), from the official CMS tabular data. M61.551 and M61.559 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. M61.551 and M61.559 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.
| M61.551Other ossification of muscle, right thigh | M61.559Other ossification of muscle, unspecified thigh | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | M00-M99 — Diseases of the musculoskeletal system and connective tissue | M00-M99 — Diseases of the musculoskeletal system and connective tissue |
| Definition | Other ossification of muscle, right thigh is a billable ICD-10-CM diagnosis code (M61.551). | Other ossification of muscle, unspecified thigh is a billable ICD-10-CM diagnosis code (M61.559). |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources