ICD-10-CM 2027 diagnosis code
S66.1Injury of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level
S66.1 is a header code, so it can't be reported by itself. Choose one of the 4 more specific codes beneath it and add the required 7th character.Short description: Inj flexor musc/fasc/tend and unsp finger 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 S66.1
S66.1 is the ICD-10-CM diagnosis code for injury of flexor muscle, fascia and tendon of other and unspecified finger 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 4 subcodes must be used instead.
Within S66, choose S66.1 (flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level) only when documentation doesn't support a more specific option: long flexor muscle, fascia and tendon of thumb at wrist and hand level (S66.0), extensor muscle, fascia and tendon of thumb at wrist and hand level (S66.2), extensor muscle, fascia and tendon of other and unspecified finger at wrist and hand level (S66.3), intrinsic muscle, fascia and tendon of thumb at wrist and hand level (S66.4), intrinsic muscle, fascia and tendon of other and unspecified finger at wrist and hand level (S66.5), other specified muscles, fascia and tendons at wrist and hand level (S66.8) and unspecified muscle, fascia and tendon at wrist and hand level (S66.9).
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.
The conditions in its Excludes2 note aren't part of S66.1, but may be coded alongside it if the patient has both: Injury of long flexor muscle, fascia and tendon of thumb at wrist and hand level (S66.0-).
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
- S66.10Unspecified injury of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.100Unspecified injury of flexor muscle, fascia and tendon of right index finger at wrist and hand level
- S66.101Unspecified injury of flexor muscle, fascia and tendon of left index finger at wrist and hand level
- S66.102Unspecified injury of flexor muscle, fascia and tendon of right middle finger at wrist and hand level
- S66.103Unspecified injury of flexor muscle, fascia and tendon of left middle finger at wrist and hand level
- S66.104Unspecified injury of flexor muscle, fascia and tendon of right ring finger at wrist and hand level
- S66.105Unspecified injury of flexor muscle, fascia and tendon of left ring finger at wrist and hand level
- S66.106Unspecified injury of flexor muscle, fascia and tendon of right little finger at wrist and hand level
- S66.107Unspecified injury of flexor muscle, fascia and tendon of left little finger at wrist and hand level
- S66.108Unspecified injury of flexor muscle, fascia and tendon of other finger at wrist and hand level
- S66.109Unspecified injury of flexor muscle, fascia and tendon of unspecified finger at wrist and hand level
- S66.11Strain of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.110Strain of flexor muscle, fascia and tendon of right index finger at wrist and hand level
- S66.111Strain of flexor muscle, fascia and tendon of left index finger at wrist and hand level
- S66.112Strain of flexor muscle, fascia and tendon of right middle finger at wrist and hand level
- S66.113Strain of flexor muscle, fascia and tendon of left middle finger at wrist and hand level
- S66.114Strain of flexor muscle, fascia and tendon of right ring finger at wrist and hand level
- S66.115Strain of flexor muscle, fascia and tendon of left ring finger at wrist and hand level
- S66.116Strain of flexor muscle, fascia and tendon of right little finger at wrist and hand level
- S66.117Strain of flexor muscle, fascia and tendon of left little finger at wrist and hand level
- S66.118Strain of flexor muscle, fascia and tendon of other finger at wrist and hand level
- S66.119Strain of flexor muscle, fascia and tendon of unspecified finger at wrist and hand level
- S66.12Laceration of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.120Laceration of flexor muscle, fascia and tendon of right index finger at wrist and hand level
- S66.121Laceration of flexor muscle, fascia and tendon of left index finger at wrist and hand level
- S66.122Laceration of flexor muscle, fascia and tendon of right middle finger at wrist and hand level
- S66.123Laceration of flexor muscle, fascia and tendon of left middle finger at wrist and hand level
- S66.124Laceration of flexor muscle, fascia and tendon of right ring finger at wrist and hand level
- S66.125Laceration of flexor muscle, fascia and tendon of left ring finger at wrist and hand level
- S66.126Laceration of flexor muscle, fascia and tendon of right little finger at wrist and hand level
- S66.127Laceration of flexor muscle, fascia and tendon of left little finger at wrist and hand level
- S66.128Laceration of flexor muscle, fascia and tendon of other finger at wrist and hand level
- S66.129Laceration of flexor muscle, fascia and tendon of unspecified finger at wrist and hand level
- S66.19Other injury of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.190Other injury of flexor muscle, fascia and tendon of right index finger at wrist and hand level
- S66.191Other injury of flexor muscle, fascia and tendon of left index finger at wrist and hand level
- S66.192Other injury of flexor muscle, fascia and tendon of right middle finger at wrist and hand level
- S66.193Other injury of flexor muscle, fascia and tendon of left middle finger at wrist and hand level
- S66.194Other injury of flexor muscle, fascia and tendon of right ring finger at wrist and hand level
- S66.195Other injury of flexor muscle, fascia and tendon of left ring finger at wrist and hand level
- S66.196Other injury of flexor muscle, fascia and tendon of right little finger at wrist and hand level
- S66.197Other injury of flexor muscle, fascia and tendon of left little finger at wrist and hand level
- S66.198Other injury of flexor muscle, fascia and tendon of other finger at wrist and hand level
- S66.199Other injury of flexor muscle, fascia and tendon of unspecified finger at wrist and hand level
- Ainitial encounter
- Dsubsequent encounter
- Ssequela
Coding notes
- Injury of long flexor muscle, fascia and tendon of thumb at wrist and hand level (S66.0-)
Notes that apply from higher levels
Instructions written at a parent level also apply to S66.1.
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
- 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 S66.1
Is S66.1 billable?
- No. S66.1 is a header code. Report one of its more specific subcodes instead.