S66.310A — Strain of extensor muscle, fascia and tendon of right index finger at wrist and hand level, initial encounter
Is S66.310A billable?
Yes — S66.310A is billable for FY2027. S66.310A is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. S66.310A may be submitted for encounters from October 1, 2026 through September 30, 2027.
S66.310A at a glance
| Code | S66.310A |
|---|---|
| Description | Strain of extensor muscle, fascia and tendon of right index finger at wrist and hand level, initial encounter |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
| 7th character "A" | initial encounter |
What does the 7th character "A" mean in S66.310A?
In S66.310A, the 7th character A means initial encounter. The 7th character is required for S66.310A to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
Which MS-DRGs does S66.310A group to?
S66.310A sits in MDC 08 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 562Fracture, Sprain, Strain and Dislocation Except Femur, Hip, Pelvis and Thigh with MCCmedical
- 563Fracture, Sprain, Strain and Dislocation Except Femur, Hip, Pelvis and Thigh without MCCmedical
How is S66.310A listed in the Alphabetic Index?
The Alphabetic Index lists these routes under S66.31, the nearest indexed parent of S66.310A. Use them to find the family, then select the specific code.
- Injury › muscle › finger › index › extensor › hand level › strain
- Injury › muscle › finger › little › extensor › hand level › strain
- Injury › muscle › finger › middle › extensor › hand level › strain
- Injury › muscle › finger › ring › extensor › hand level › strain
Use additional code — inherited from Chapter 19
Report an additional code alongside S66.310A to fully describe the condition. S66.310A 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 S66.310A, but a patient may have both at the same time. When documentation supports it, S66.310A and the excluded code may both be reported.
Excludes2 — not included here — inherited from S60-S69
The conditions below are not part of S66.310A, but a patient may have both at the same time. When documentation supports it, S66.310A and the excluded code may both be reported.
Excludes2 — not included here — inherited from S66
The conditions below are not part of S66.310A, but a patient may have both at the same time. When documentation supports it, S66.310A and the excluded code may both be reported.
- sprain of joints and ligaments of wrist and hand (S63.-)
Excludes2 — not included here — inherited from S66.3
The conditions below are not part of S66.310A, but a patient may have both at the same time. When documentation supports it, S66.310A and the excluded code may both be reported.
- Injury of extensor muscle, fascia and tendon of thumb at wrist and hand level (S66.2-)
Code also — inherited from S66
Two codes may be needed to describe the condition fully. Whether S66.310A is sequenced first depends on the reason for the encounter.
- any associated open wound (S61.-)
How long has S66.310A existed?
S66.310A 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.