ICD-10-CM 2027 diagnosis code
S66Injury of muscle, fascia and tendon at wrist and hand level
Not billable — use a more specific code
S66 is a header code, so it can't be reported by itself. Choose one of the 8 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 S66
S66 is the ICD-10-CM diagnosis code for injury of muscle, fascia and tendon at wrist and hand level. It belongs to 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 8 subcodes must be used instead.
To report this condition, pick the subcode that matches the documentation: S66.0 (level), S66.1 (level), S66.2 (level), S66.3 (level), S66.4 (level), S66.5 (level), S66.8 (level) and S66.9 (level).
The conditions in its Excludes2 note aren't part of S66, but may be coded alongside it if the patient has both: sprain of joints and ligaments of wrist and hand (S63.-).
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 S66
- S66.0Injury of long flexor muscle, fascia and tendon of thumb at wrist and hand level
- S66.00Unspecified injury of long flexor muscle, fascia and tendon of thumb at wrist and hand level
- S66.001Unspecified injury of long flexor muscle, fascia and tendon of right thumb at wrist and hand level
- S66.002Unspecified injury of long flexor muscle, fascia and tendon of left thumb at wrist and hand level
- S66.009Unspecified injury of long flexor muscle, fascia and tendon of unspecified thumb at wrist and hand level
- S66.01Strain of long flexor muscle, fascia and tendon of thumb at wrist and hand level
- S66.02Laceration of long flexor muscle, fascia and tendon of thumb at wrist and hand level
- S66.09Other specified injury of long flexor muscle, fascia and tendon of thumb at wrist and hand level
- S66.091Other specified injury of long flexor muscle, fascia and tendon of right thumb at wrist and hand level
- S66.092Other specified injury of long flexor muscle, fascia and tendon of left thumb at wrist and hand level
- S66.099Other specified injury of long flexor muscle, fascia and tendon of unspecified thumb at wrist and hand level
- S66.00Unspecified injury of long flexor muscle, fascia and tendon of thumb at wrist and hand level
- S66.1Injury of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- 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
- S66.10Unspecified injury of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.2Injury of extensor muscle, fascia and tendon of thumb at wrist and hand level
- S66.20Unspecified injury of extensor muscle, fascia and tendon of thumb at wrist and hand level
- S66.201Unspecified injury of extensor muscle, fascia and tendon of right thumb at wrist and hand level
- S66.202Unspecified injury of extensor muscle, fascia and tendon of left thumb at wrist and hand level
- S66.209Unspecified injury of extensor muscle, fascia and tendon of unspecified thumb at wrist and hand level
- S66.21Strain of extensor muscle, fascia and tendon of thumb at wrist and hand level
- S66.22Laceration of extensor muscle, fascia and tendon of thumb at wrist and hand level
- S66.29Other specified injury of extensor muscle, fascia and tendon of thumb at wrist and hand level
- S66.291Other specified injury of extensor muscle, fascia and tendon of right thumb at wrist and hand level
- S66.292Other specified injury of extensor muscle, fascia and tendon of left thumb at wrist and hand level
- S66.299Other specified injury of extensor muscle, fascia and tendon of unspecified thumb at wrist and hand level
- S66.20Unspecified injury of extensor muscle, fascia and tendon of thumb at wrist and hand level
- S66.3Injury of extensor muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.30Unspecified injury of extensor muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.300Unspecified injury of extensor muscle, fascia and tendon of right index finger at wrist and hand level
- S66.301Unspecified injury of extensor muscle, fascia and tendon of left index finger at wrist and hand level
- S66.302Unspecified injury of extensor muscle, fascia and tendon of right middle finger at wrist and hand level
- S66.303Unspecified injury of extensor muscle, fascia and tendon of left middle finger at wrist and hand level
- S66.304Unspecified injury of extensor muscle, fascia and tendon of right ring finger at wrist and hand level
- S66.305Unspecified injury of extensor muscle, fascia and tendon of left ring finger at wrist and hand level
- S66.306Unspecified injury of extensor muscle, fascia and tendon of right little finger at wrist and hand level
- S66.307Unspecified injury of extensor muscle, fascia and tendon of left little finger at wrist and hand level
- S66.308Unspecified injury of extensor muscle, fascia and tendon of other finger at wrist and hand level
- S66.309Unspecified injury of extensor muscle, fascia and tendon of unspecified finger at wrist and hand level
- S66.31Strain of extensor muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.310Strain of extensor muscle, fascia and tendon of right index finger at wrist and hand level
- S66.311Strain of extensor muscle, fascia and tendon of left index finger at wrist and hand level
- S66.312Strain of extensor muscle, fascia and tendon of right middle finger at wrist and hand level
- S66.313Strain of extensor muscle, fascia and tendon of left middle finger at wrist and hand level
- S66.314Strain of extensor muscle, fascia and tendon of right ring finger at wrist and hand level
- S66.315Strain of extensor muscle, fascia and tendon of left ring finger at wrist and hand level
- S66.316Strain of extensor muscle, fascia and tendon of right little finger at wrist and hand level
- S66.317Strain of extensor muscle, fascia and tendon of left little finger at wrist and hand level
- S66.318Strain of extensor muscle, fascia and tendon of other finger at wrist and hand level
- S66.319Strain of extensor muscle, fascia and tendon of unspecified finger at wrist and hand level
- S66.32Laceration of extensor muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.320Laceration of extensor muscle, fascia and tendon of right index finger at wrist and hand level
- S66.321Laceration of extensor muscle, fascia and tendon of left index finger at wrist and hand level
- S66.322Laceration of extensor muscle, fascia and tendon of right middle finger at wrist and hand level
- S66.323Laceration of extensor muscle, fascia and tendon of left middle finger at wrist and hand level
- S66.324Laceration of extensor muscle, fascia and tendon of right ring finger at wrist and hand level
- S66.325Laceration of extensor muscle, fascia and tendon of left ring finger at wrist and hand level
- S66.326Laceration of extensor muscle, fascia and tendon of right little finger at wrist and hand level
- S66.327Laceration of extensor muscle, fascia and tendon of left little finger at wrist and hand level
- S66.328Laceration of extensor muscle, fascia and tendon of other finger at wrist and hand level
- S66.329Laceration of extensor muscle, fascia and tendon of unspecified finger at wrist and hand level
- S66.39Other injury of extensor muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.390Other injury of extensor muscle, fascia and tendon of right index finger at wrist and hand level
- S66.391Other injury of extensor muscle, fascia and tendon of left index finger at wrist and hand level
- S66.392Other injury of extensor muscle, fascia and tendon of right middle finger at wrist and hand level
- S66.393Other injury of extensor muscle, fascia and tendon of left middle finger at wrist and hand level
- S66.394Other injury of extensor muscle, fascia and tendon of right ring finger at wrist and hand level
- S66.395Other injury of extensor muscle, fascia and tendon of left ring finger at wrist and hand level
- S66.396Other injury of extensor muscle, fascia and tendon of right little finger at wrist and hand level
- S66.397Other injury of extensor muscle, fascia and tendon of left little finger at wrist and hand level
- S66.398Other injury of extensor muscle, fascia and tendon of other finger at wrist and hand level
- S66.399Other injury of extensor muscle, fascia and tendon of unspecified finger at wrist and hand level
- S66.30Unspecified injury of extensor muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.4Injury of intrinsic muscle, fascia and tendon of thumb at wrist and hand level
- S66.40Unspecified injury of intrinsic muscle, fascia and tendon of thumb at wrist and hand level
- S66.401Unspecified injury of intrinsic muscle, fascia and tendon of right thumb at wrist and hand level
- S66.402Unspecified injury of intrinsic muscle, fascia and tendon of left thumb at wrist and hand level
- S66.409Unspecified injury of intrinsic muscle, fascia and tendon of unspecified thumb at wrist and hand level
- S66.41Strain of intrinsic muscle, fascia and tendon of thumb at wrist and hand level
- S66.42Laceration of intrinsic muscle, fascia and tendon of thumb at wrist and hand level
- S66.49Other specified injury of intrinsic muscle, fascia and tendon of thumb at wrist and hand level
- S66.491Other specified injury of intrinsic muscle, fascia and tendon of right thumb at wrist and hand level
- S66.492Other specified injury of intrinsic muscle, fascia and tendon of left thumb at wrist and hand level
- S66.499Other specified injury of intrinsic muscle, fascia and tendon of unspecified thumb at wrist and hand level
- S66.40Unspecified injury of intrinsic muscle, fascia and tendon of thumb at wrist and hand level
- S66.5Injury of intrinsic muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.50Unspecified injury of intrinsic muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.500Unspecified injury of intrinsic muscle, fascia and tendon of right index finger at wrist and hand level
- S66.501Unspecified injury of intrinsic muscle, fascia and tendon of left index finger at wrist and hand level
- S66.502Unspecified injury of intrinsic muscle, fascia and tendon of right middle finger at wrist and hand level
- S66.503Unspecified injury of intrinsic muscle, fascia and tendon of left middle finger at wrist and hand level
- S66.504Unspecified injury of intrinsic muscle, fascia and tendon of right ring finger at wrist and hand level
- S66.505Unspecified injury of intrinsic muscle, fascia and tendon of left ring finger at wrist and hand level
- S66.506Unspecified injury of intrinsic muscle, fascia and tendon of right little finger at wrist and hand level
- S66.507Unspecified injury of intrinsic muscle, fascia and tendon of left little finger at wrist and hand level
- S66.508Unspecified injury of intrinsic muscle, fascia and tendon of other finger at wrist and hand level
- S66.509Unspecified injury of intrinsic muscle, fascia and tendon of unspecified finger at wrist and hand level
- S66.51Strain of intrinsic muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.510Strain of intrinsic muscle, fascia and tendon of right index finger at wrist and hand level
- S66.511Strain of intrinsic muscle, fascia and tendon of left index finger at wrist and hand level
- S66.512Strain of intrinsic muscle, fascia and tendon of right middle finger at wrist and hand level
- S66.513Strain of intrinsic muscle, fascia and tendon of left middle finger at wrist and hand level
- S66.514Strain of intrinsic muscle, fascia and tendon of right ring finger at wrist and hand level
- S66.515Strain of intrinsic muscle, fascia and tendon of left ring finger at wrist and hand level
- S66.516Strain of intrinsic muscle, fascia and tendon of right little finger at wrist and hand level
- S66.517Strain of intrinsic muscle, fascia and tendon of left little finger at wrist and hand level
- S66.518Strain of intrinsic muscle, fascia and tendon of other finger at wrist and hand level
- S66.519Strain of intrinsic muscle, fascia and tendon of unspecified finger at wrist and hand level
- S66.52Laceration of intrinsic muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.520Laceration of intrinsic muscle, fascia and tendon of right index finger at wrist and hand level
- S66.521Laceration of intrinsic muscle, fascia and tendon of left index finger at wrist and hand level
- S66.522Laceration of intrinsic muscle, fascia and tendon of right middle finger at wrist and hand level
- S66.523Laceration of intrinsic muscle, fascia and tendon of left middle finger at wrist and hand level
- S66.524Laceration of intrinsic muscle, fascia and tendon of right ring finger at wrist and hand level
- S66.525Laceration of intrinsic muscle, fascia and tendon of left ring finger at wrist and hand level
- S66.526Laceration of intrinsic muscle, fascia and tendon of right little finger at wrist and hand level
- S66.527Laceration of intrinsic muscle, fascia and tendon of left little finger at wrist and hand level
- S66.528Laceration of intrinsic muscle, fascia and tendon of other finger at wrist and hand level
- S66.529Laceration of intrinsic muscle, fascia and tendon of unspecified finger at wrist and hand level
- S66.59Other injury of intrinsic muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.590Other injury of intrinsic muscle, fascia and tendon of right index finger at wrist and hand level
- S66.591Other injury of intrinsic muscle, fascia and tendon of left index finger at wrist and hand level
- S66.592Other injury of intrinsic muscle, fascia and tendon of right middle finger at wrist and hand level
- S66.593Other injury of intrinsic muscle, fascia and tendon of left middle finger at wrist and hand level
- S66.594Other injury of intrinsic muscle, fascia and tendon of right ring finger at wrist and hand level
- S66.595Other injury of intrinsic muscle, fascia and tendon of left ring finger at wrist and hand level
- S66.596Other injury of intrinsic muscle, fascia and tendon of right little finger at wrist and hand level
- S66.597Other injury of intrinsic muscle, fascia and tendon of left little finger at wrist and hand level
- S66.598Other injury of intrinsic muscle, fascia and tendon of other finger at wrist and hand level
- S66.599Other injury of intrinsic muscle, fascia and tendon of unspecified finger at wrist and hand level
- S66.50Unspecified injury of intrinsic muscle, fascia and tendon of other and unspecified finger at wrist and hand level
- S66.8Injury of other specified muscles, fascia and tendons at wrist and hand level
- S66.80Unspecified injury of other specified muscles, fascia and tendons at wrist and hand level
- S66.801Unspecified injury of other specified muscles, fascia and tendons at wrist and hand level, right hand
- S66.802Unspecified injury of other specified muscles, fascia and tendons at wrist and hand level, left hand
- S66.809Unspecified injury of other specified muscles, fascia and tendons at wrist and hand level, unspecified hand
- S66.81Strain of other specified muscles, fascia and tendons at wrist and hand level
- S66.82Laceration of other specified muscles, fascia and tendons at wrist and hand level
- S66.821Laceration of other specified muscles, fascia and tendons at wrist and hand level, right hand
- S66.822Laceration of other specified muscles, fascia and tendons at wrist and hand level, left hand
- S66.829Laceration of other specified muscles, fascia and tendons at wrist and hand level, unspecified hand
- S66.89Other injury of other specified muscles, fascia and tendons at wrist and hand level
- S66.891Other injury of other specified muscles, fascia and tendons at wrist and hand level, right hand
- S66.892Other injury of other specified muscles, fascia and tendons at wrist and hand level, left hand
- S66.899Other injury of other specified muscles, fascia and tendons at wrist and hand level, unspecified hand
- S66.80Unspecified injury of other specified muscles, fascia and tendons at wrist and hand level
- S66.9Injury of unspecified muscle, fascia and tendon at wrist and hand level
- S66.90Unspecified injury of unspecified muscle, fascia and tendon at wrist and hand level
- S66.901Unspecified injury of unspecified muscle, fascia and tendon at wrist and hand level, right hand
- S66.902Unspecified injury of unspecified muscle, fascia and tendon at wrist and hand level, left hand
- S66.909Unspecified injury of unspecified muscle, fascia and tendon at wrist and hand level, unspecified hand
- S66.91Strain of unspecified muscle, fascia and tendon at wrist and hand level
- S66.92Laceration of unspecified muscle, fascia and tendon at wrist and hand level
- S66.99Other injury of unspecified muscle, fascia and tendon at wrist and hand level
- S66.90Unspecified injury of unspecified muscle, fascia and tendon at wrist and hand level
Coding notes
Notes that apply from higher levels
Instructions written at a parent level also apply to S66.
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.
Codes whose notes reference S66
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
Is S66 billable?
- No. S66 is a header code. Report one of its more specific subcodes instead.