S66.01Header code — not billable
Strain of long flexor muscle, fascia and tendon of thumb at wrist and hand level
Short description: Strain of long flexor musc/fasc/tend thumb at wrs/hnd lv
- Chapter
- 19. Injury, poisoning and certain other consequences of external causes
- Category
- S66
- Effective date
- October 1, 2026
Related codes in category S66
S66Injury of muscle, fascia and tendon at wrist and hand levelS66.0Injury of long flexor musc/fasc/tend thumb at wrs/hnd lvS66.00Unsp inj long flexor musc/fasc/tend thumb at wrs/hnd lvS66.001Unsp inj long flexor musc/fasc/tend r thm at wrs/hnd lvS66.001AUnsp inj long flxr musc/fasc/tend r thm at wrs/hnd lv, initYesS66.001DUnsp inj long flxr musc/fasc/tend r thm at wrs/hnd lv, subsYesS66.001SUnsp inj long flxr musc/fasc/tend r thm at wrs/hnd lv, sqlaYesS66.002Unsp inj long flexor musc/fasc/tend l thm at wrs/hnd lvS66.002AUnsp inj long flxr musc/fasc/tend l thm at wrs/hnd lv, initYesS66.002DUnsp inj long flxr musc/fasc/tend l thm at wrs/hnd lv, subsYesS66.002SUnsp inj long flxr musc/fasc/tend l thm at wrs/hnd lv, sqlaYesS66.009Unsp injury of long flexor musc/fasc/tend thmb at wrs/hnd lv
Frequently asked questions
What is ICD-10 code S66.01?
S66.01 is an ICD-10-CM diagnosis code for Strain of long flexor muscle, fascia and tendon of thumb at wrist and hand level.
Is S66.01 a billable code?
No. S66.01 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 S66.01 in?
S66.01 falls under Chapter 19: Injury, poisoning and certain other consequences of external causes.
When did S66.01 become effective?
S66.01 has been effective since October 1, 2026, per the CMS/CDC ICD-10-CM annual release.
What other codes are related to S66.01?
S66.01 belongs to category S66, 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.