Disorders of synovium and tendon (M65-M67) ICD-10-CM
The M65–M67 section covers disorders of synovium and tendon with 497 ICD-10-CM diagnosis codes, of which 376 are billable in fiscal year 2026. The section is organized into the 3 code ranges listed below.
Code Ranges in This Section 3 ranges · 497 codes
| Code Range | Title | Codes | Billable |
|---|---|---|---|
| M65 | Synovitis and tenosynovitis (M65) | 179 | 133 |
| M66 | Spontaneous rupture of synovium and tendon (M66) | 135 | 103 |
| M67 | Other disorders of synovium and tendon (M67) | 183 | 140 |
The info icon previews the code ranges inside each row and its instructional notations from the official Tabular List.
About the M65–M67 Code Range
ICD-10 codes M65-M67 are used to classify various disorders involving the synovium and tendons, including inflammation, infections, ruptures, and other tendon or synovial abnormalities. These codes specify the condition type and the affected anatomical location, such as the shoulder, hand, foot, or knee.
The M65 series covers synovitis and tenosynovitis and includes codes for abscesses of tendon sheaths (e.g., M65.0), other infective synovitis (e.g., M65.1), calcific tendinitis (e.g., M65.2), and trigger finger or thumb (e.g., M65.3). For example, "abscess of tendon sheath" or "tenosynovitis" can be identified using these codes. The M66 range pertains to spontaneous rupture of tendons and synovium, differentiating between extensor, flexor, and other tendon ruptures, with laterality and site-specific distinctions (e.g., M66.21 for spontaneous rupture of extensor tendons of the right shoulder). The M67 codes address other disorders of the synovium and tendon, including acquired short Achilles tendon (M67.0), synovial hypertrophy (M67.2), transient synovitis (M67.3), ganglions (M67.4), plica syndrome (M67.5), and other specified or unspecified synovium and tendon disorders (e.g., M67.8 and M67.9). Medical coders can use the provided synonyms to match common terms like “trigger finger,” “rupture of synovium,” or “ganglion cyst” to the corresponding ICD-10 code for accurate documentation and billing.
Questions About This Page
How many codes are in the M65-M67 range?
The M65-M67 range contains 497 ICD-10-CM diagnosis codes in FY 2026. 376 of them are billable, and the rest are category headers that organize the section.
What conditions does M65-M67 cover?
The range covers disorders of synovium and tendon. The code ranges listed above break it into groups of related conditions, and each one links to its own page with the full code list.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
