M65Header code — not billable
Synovitis and tenosynovitis
- Chapter
- 13. Diseases of the musculoskeletal system and connective tissue
- Category
- M65
- Effective date
- October 1, 2026
Related codes in category M65
M65.0Abscess of tendon sheathM65.00Abscess of tendon sheath, unspecified siteYesM65.01Abscess of tendon sheath, shoulderM65.011Abscess of tendon sheath, right shoulderYesM65.012Abscess of tendon sheath, left shoulderYesM65.019Abscess of tendon sheath, unspecified shoulderYesM65.02Abscess of tendon sheath, upper armM65.021Abscess of tendon sheath, right upper armYesM65.022Abscess of tendon sheath, left upper armYesM65.029Abscess of tendon sheath, unspecified upper armYesM65.03Abscess of tendon sheath, forearmM65.031Abscess of tendon sheath, right forearmYes
Frequently asked questions
What is ICD-10 code M65?
M65 is an ICD-10-CM diagnosis code for Synovitis and tenosynovitis.
Is M65 a billable code?
No. M65 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 M65 in?
M65 falls under Chapter 13: Diseases of the musculoskeletal system and connective tissue.
When did M65 become effective?
M65 has been effective since October 1, 2026, per the CMS/CDC ICD-10-CM annual release.
What other codes are related to M65?
M65 belongs to category M65, 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.