ICD-10-CM · FY 2026 APRIL UPDATE

S66.31

Strain of extensor muscle, fascia and tendon of other and unspecified finger at wrist and hand level

Diagnosis reference

Nonbillable category

This entry is a category or subcategory. Choose the appropriate billable descendant based on the clinical documentation.

Effective periodOctober 1, 2026–September 30, 2027

SourceCMS ICD-10-CM order file

ClassificationDiagnosis · clinical modification

Related entries

Up to 30 descendants in this category

CODE	DESCRIPTION	TYPE
S66.310	Strain of extensor muscle, fascia and tendon of right index finger at wrist and hand level	Category
S66.310A	Strain of extensor muscle, fascia and tendon of right index finger at wrist and hand level, initial encounter	Billable
S66.310D	Strain of extensor muscle, fascia and tendon of right index finger at wrist and hand level, subsequent encounter	Billable
S66.310S	Strain of extensor muscle, fascia and tendon of right index finger at wrist and hand level, sequela	Billable
S66.311	Strain of extensor muscle, fascia and tendon of left index finger at wrist and hand level	Category
S66.311A	Strain of extensor muscle, fascia and tendon of left index finger at wrist and hand level, initial encounter	Billable
S66.311D	Strain of extensor muscle, fascia and tendon of left index finger at wrist and hand level, subsequent encounter	Billable
S66.311S	Strain of extensor muscle, fascia and tendon of left index finger at wrist and hand level, sequela	Billable
S66.312	Strain of extensor muscle, fascia and tendon of right middle finger at wrist and hand level	Category
S66.312A	Strain of extensor muscle, fascia and tendon of right middle finger at wrist and hand level, initial encounter	Billable
S66.312D	Strain of extensor muscle, fascia and tendon of right middle finger at wrist and hand level, subsequent encounter	Billable
S66.312S	Strain of extensor muscle, fascia and tendon of right middle finger at wrist and hand level, sequela	Billable
S66.313	Strain of extensor muscle, fascia and tendon of left middle finger at wrist and hand level	Category
S66.313A	Strain of extensor muscle, fascia and tendon of left middle finger at wrist and hand level, initial encounter	Billable
S66.313D	Strain of extensor muscle, fascia and tendon of left middle finger at wrist and hand level, subsequent encounter	Billable
S66.313S	Strain of extensor muscle, fascia and tendon of left middle finger at wrist and hand level, sequela	Billable
S66.314	Strain of extensor muscle, fascia and tendon of right ring finger at wrist and hand level	Category
S66.314A	Strain of extensor muscle, fascia and tendon of right ring finger at wrist and hand level, initial encounter	Billable
S66.314D	Strain of extensor muscle, fascia and tendon of right ring finger at wrist and hand level, subsequent encounter	Billable
S66.314S	Strain of extensor muscle, fascia and tendon of right ring finger at wrist and hand level, sequela	Billable
S66.315	Strain of extensor muscle, fascia and tendon of left ring finger at wrist and hand level	Category
S66.315A	Strain of extensor muscle, fascia and tendon of left ring finger at wrist and hand level, initial encounter	Billable
S66.315D	Strain of extensor muscle, fascia and tendon of left ring finger at wrist and hand level, subsequent encounter	Billable
S66.315S	Strain of extensor muscle, fascia and tendon of left ring finger at wrist and hand level, sequela	Billable
S66.316	Strain of extensor muscle, fascia and tendon of right little finger at wrist and hand level	Category
S66.316A	Strain of extensor muscle, fascia and tendon of right little finger at wrist and hand level, initial encounter	Billable
S66.316D	Strain of extensor muscle, fascia and tendon of right little finger at wrist and hand level, subsequent encounter	Billable
S66.316S	Strain of extensor muscle, fascia and tendon of right little finger at wrist and hand level, sequela	Billable
S66.317	Strain of extensor muscle, fascia and tendon of left little finger at wrist and hand level	Category
S66.317A	Strain of extensor muscle, fascia and tendon of left little finger at wrist and hand level, initial encounter	Billable

Use the complete reference

This reference does not reproduce the full tabular hierarchy, inclusion notes, Excludes1/2 notes, sequencing instructions, or seventh-character rules. Review the official tables and coding guidelines.

Open official CMS files

ICD-10-CM codes describe diagnoses. They do not have an independent Medicare PFS reimbursement amount, and billability alone does not establish coverage.