S66.21 — Strain of extensor muscle, fascia and tendon of thumb at wrist and hand level
Is S66.21 billable?
No — S66.21 is a non-billable header code. S66.21 groups more specific codes and cannot be submitted on a claim. A valid ICD-10-CM code must be reported at the highest level of specificity available in its branch. Select one of the 9 billable codes beneath S66.21.
Billable codes under this header
- S66.211AStrain of extensor muscle, fascia and tendon of right thumb at wrist and hand level, initial encounter
- S66.211DStrain of extensor muscle, fascia and tendon of right thumb at wrist and hand level, subsequent encounter
- S66.211SStrain of extensor muscle, fascia and tendon of right thumb at wrist and hand level, sequela
- S66.212AStrain of extensor muscle, fascia and tendon of left thumb at wrist and hand level, initial encounter
- S66.212DStrain of extensor muscle, fascia and tendon of left thumb at wrist and hand level, subsequent encounter
- S66.212SStrain of extensor muscle, fascia and tendon of left thumb at wrist and hand level, sequela
- S66.219AStrain of extensor muscle, fascia and tendon of unspecified thumb at wrist and hand level, initial encounter
- S66.219DStrain of extensor muscle, fascia and tendon of unspecified thumb at wrist and hand level, subsequent encounter
- S66.219SStrain of extensor muscle, fascia and tendon of unspecified thumb at wrist and hand level, sequela
S66.21 at a glance
| Code | S66.21 |
|---|---|
| Description | Strain of extensor muscle, fascia and tendon of thumb at wrist and hand level |
| Billable | No — header code |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
How is S66.21 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to S66.21. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Injury › muscle › thumb › extensor › hand level › strain
Use additional code — inherited from Chapter 19
Report an additional code alongside S66.21 to fully describe the condition. S66.21 is sequenced first.
- code to identify any retained foreign body, if applicable (Z18.-)
Excludes2 — not included here — inherited from Chapter 19
The conditions below are not part of S66.21, but a patient may have both at the same time. When documentation supports it, S66.21 and the excluded code may both be reported.
Excludes2 — not included here — inherited from S60-S69
The conditions below are not part of S66.21, but a patient may have both at the same time. When documentation supports it, S66.21 and the excluded code may both be reported.
Excludes2 — not included here — inherited from S66
The conditions below are not part of S66.21, but a patient may have both at the same time. When documentation supports it, S66.21 and the excluded code may both be reported.
- sprain of joints and ligaments of wrist and hand (S63.-)
Code also — inherited from S66
Two codes may be needed to describe the condition fully. Whether S66.21 is sequenced first depends on the reason for the encounter.
- any associated open wound (S61.-)
What codes fall under S66.21? (3)
- S66.211Strain of extensor muscle, fascia and tendon of right thumb at wrist and hand levelnot billable
- S66.212Strain of extensor muscle, fascia and tendon of left thumb at wrist and hand levelnot billable
- S66.219Strain of extensor muscle, fascia and tendon of unspecified thumb at wrist and hand levelnot billable
How long has S66.21 existed?
S66.21 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.
What other codes are in the S66.2 family? (3)
- S66.20Unspecified injury of extensor muscle, fascia and tendon of thumb at wrist and hand levelnot billable
- S66.22Laceration of extensor muscle, fascia and tendon of thumb at wrist and hand levelnot billable
- S66.29Other specified injury of extensor muscle, fascia and tendon of thumb at wrist and hand levelnot billable