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ICD-10-CM 2027 diagnosis code

S66.021Laceration of long flexor muscle, fascia and tendon of right thumb at wrist and hand level

Not billable — use a more specific codeRequires 7th character

S66.021 is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it and add the required 7th character.Short description: Lacerat long flexor musc/fasc/tend right thumb at wrs/hnd lv

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 S66.021

S66.021 is the ICD-10-CM diagnosis code for laceration of long flexor muscle, fascia and tendon of right thumb at wrist and hand level. It belongs to category S66 (injury of muscle, fascia and tendon at wrist and hand level), block S60-S69 (injuries to the wrist, hand and fingers) and chapter 19 (injury, poisoning and certain other consequences of external causes). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

Within S66.02 (laceration of long flexor muscle, fascia and tendon of thumb at wrist and hand level), S66.021 is specifically for laceration of long flexor muscle, fascia and tendon of right thumb at wrist and hand level. Related codes cover left thumb at wrist and hand level (S66.022) and unspecified thumb at wrist and hand level (S66.029).

Codes in this range require a 7th character: A for initial encounter, D for subsequent encounter and S for sequela. Use placeholder "X" characters to fill any empty positions before the 7th character.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

7th character

The appropriate 7th character is to be added to each code from category S66

Notes that apply from higher levels

Instructions written at a parent level also apply to S66.021.

› From S66 Injury of muscle, fascia and tendon at wrist and hand level
Excludes2
  • sprain of joints and ligaments of wrist and hand (S63.-)
Code also
  • any associated open wound (S61.-)

Broader instructions also apply from S60-S69 Injuries to the wrist, hand and fingers and Chapter 19: Injury, poisoning and certain other consequences of external causes.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about S66.021

Is S66.021 billable?

No. S66.021 is a header code. Report one of its more specific subcodes instead.