M66

Non-billable

Spontaneous rupture of synovium and tendon

M66 is the ICD-10-CM code for Spontaneous rupture of synovium and tendon. It is a non-billable category code — use a more specific child code such as M66.0 for billing.

Status
Header (non-billable)
Chapter
M00-M99
Subcodes
6
Edition
FY2026

M00-M99 Diseases of the musculoskeletal system and connective tissue

What this means — in plain language

MedlinePlus · NIH

What are joints? Your joints are places where two or more bones come together. Your shoulders, elbows, hips, knees, and knuckles are all joints. Your spine has joints, too. But joints are more than bones. They include the soft tissues around them, such as cartilage, tendons and ligaments. Cartilage is the hard slippery flexible tissue that covers the ends of your bones at a joint. Tendons are tough, flexible bands…

Read more about Joint Disorders at MedlinePlus ↗

Source: U.S. National Library of Medicine (MedlinePlus). Informational only — not medical advice.

Includes

  • rupture that occurs when a normal force is applied to tissues that are inferred to have less than normal strength

Excludes2 — not included here

  • rotator cuff syndrome (M75.1-)
  • rupture where an abnormal force is applied to normal tissue - see injury of tendon by body region

Frequently asked questions

What is ICD-10 code M66?
M66 is the ICD-10-CM code for "Spontaneous rupture of synovium and tendon". It falls under M00-M99 Diseases of the musculoskeletal system and connective tissue.
Is M66 a billable code?
No — M66 is a non-billable header code. Use a more specific child code (such as M66.0) for billing.
What are the subcodes of M66?
M66 has 6 more specific child codes, including M66.0, M66.1, M66.2.

Source: CMS ICD-10-CM FY2026. For informational purposes only — not medical advice. See our medical disclaimer.

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