ICD-10-CM 2027 diagnosis code
M66.8Spontaneous rupture of other tendons
M66.8 is a header code, so it can't be reported by itself. Choose one of the 10 more specific codes beneath it.
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About M66.8
M66.8 is the ICD-10-CM diagnosis code for spontaneous rupture of other tendons. It belongs to category M66 (spontaneous rupture of synovium and tendon), block M65-M67 (disorders of synovium and tendon) and chapter 13 (diseases of the musculoskeletal system and connective tissue). It is a header code, so it can't be reported by itself; one of its 10 subcodes must be used instead.
Within M66, choose M66.8 (Spontaneous rupture of other tendons) only when documentation doesn't support a more specific option: rupture of popliteal cyst (M66.0), rupture of synovium (M66.1), spontaneous rupture of extensor tendons (M66.2), spontaneous rupture of flexor tendons (M66.3) and spontaneous rupture of unspecified tendon (M66.9).
To report this condition, pick the subcode that matches the documentation: M66.80 (unspecified site), M66.81 (shoulder), M66.82 (upper arm), M66.83 (forearm), M66.84 (hand), M66.85 (thigh), M66.86 (lower leg), M66.87 (ankle and foot) and 2 more.
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Specific codes under M66.8
- M66.80Spontaneous rupture of other tendons, unspecified siteBillable
- M66.81Spontaneous rupture of other tendons, shoulder
- M66.82Spontaneous rupture of other tendons, upper arm
- M66.83Spontaneous rupture of other tendons, forearm
- M66.84Spontaneous rupture of other tendons, hand
- M66.85Spontaneous rupture of other tendons, thigh
- M66.86Spontaneous rupture of other tendons, lower leg
- M66.87Spontaneous rupture of other tendons, ankle and foot
- M66.88Spontaneous rupture of other tendons, other sitesBillable
- M66.89Spontaneous rupture of other tendons, multiple sitesBillable
Notes that apply from higher levels
Instructions written at a parent level also apply to M66.8.
› From M66 Spontaneous rupture of synovium and tendon
- rupture that occurs when a normal force is applied to tissues that are inferred to have less than normal strength
- rotator cuff syndrome (M75.1-)
- rupture where an abnormal force is applied to normal tissue - see injury of tendon by body region
Broader instructions also apply from Chapter 13: Diseases of the musculoskeletal system and connective tissue.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about M66.8
Is M66.8 billable?
- No. M66.8 is a header code. Report one of its more specific subcodes instead.