M66Header code — not billable
Spontaneous rupture of synovium and tendon
- Chapter
- 13. Diseases of the musculoskeletal system and connective tissue
- Category
- M66
- Effective date
- October 1, 2026
Related codes in category M66
M66.0Rupture of popliteal cystYesM66.1Rupture of synoviumM66.10Rupture of synovium, unspecified jointYesM66.11Rupture of synovium, shoulderM66.111Rupture of synovium, right shoulderYesM66.112Rupture of synovium, left shoulderYesM66.119Rupture of synovium, unspecified shoulderYesM66.12Rupture of synovium, elbowM66.121Rupture of synovium, right elbowYesM66.122Rupture of synovium, left elbowYesM66.129Rupture of synovium, unspecified elbowYesM66.13Rupture of synovium, wrist
Frequently asked questions
What is ICD-10 code M66?
M66 is an ICD-10-CM diagnosis code for Spontaneous rupture of synovium and tendon.
Is M66 a billable code?
No. M66 is a category/header code, not billable on its own — use one of its more specific child codes instead.
What ICD-10-CM chapter is M66 in?
M66 falls under Chapter 13: Diseases of the musculoskeletal system and connective tissue.
When did M66 become effective?
M66 has been effective since October 1, 2026, per the CMS/CDC ICD-10-CM annual release.
What other codes are related to M66?
M66 belongs to category M66, which includes 12 other codes — see the related codes list on this page.
ICD-10-CM data maintained by CDC/CMS (public domain). Always verify codes with authoritative sources before making coding or billing decisions.