M66
Spontaneous rupture of synovium and tendon
Non-billable headerNot valid on its own. Use one of the more specific codes under it.
M66 is a non-billable ICD-10-CM code category for spontaneous rupture of synovium and tendon. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are M66.0 Rupture of popliteal cyst, M66.1 Rupture of synovium, M66.2 Spontaneous rupture of extensor tendons, M66.3 Spontaneous rupture of flexor tendons and 2 more. Its coding notes include 12 Excludes2 entries.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
This code
- rotator cuff syndrome (M75.1-)
- rupture where an abnormal force is applied to normal tissue - see injury of tendon by body region
Also from chapter/block level (10 notes)
Inherited from Chapter 13 Diseases of the musculoskeletal system and connective tissue
- arthropathic psoriasis (L40.5-)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- compartment syndrome (traumatic) (T79.A-)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Includes
Further defines or gives examples of the content of the category.
This code
- rupture that occurs when a normal force is applied to tissues that are inferred to have less than normal strength
Notes
Also from chapter/block level (1 note)
Inherited from Chapter 13 Diseases of the musculoskeletal system and connective tissue
- Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition