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S66.305

⚠ Non-billable (Header)

Unspecified injury of extensor muscle, fascia and tendon of left ring finger at wrist and hand level

Injury, poisoning and certain other consequences of external causes (S00-T88)

⚠️ This is a category header code — not billable. Use a more specific child code below.

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⚠️ Excludes2

inherited

Rules inherited from parent codes.

S66.3
  • • Injury of extensor muscle, fascia and tendon of thumb at wrist and hand level (S66.2-)
S66
  • • sprain of joints and ligaments of wrist and hand (S63.-)

Child Codes (3)

S66.305AUnspecified injury of extensor muscle, fascia and tendon of left ring finger at wrist and hand level, initial encounterS66.305DUnspecified injury of extensor muscle, fascia and tendon of left ring finger at wrist and hand level, subsequent encounterS66.305SUnspecified injury of extensor muscle, fascia and tendon of left ring finger at wrist and hand level, sequela

Clinical Description

ICD-10-CM code S66.305 represents unspecified injury of extensor muscle, fascia and tendon of left ring finger at wrist and hand level. This code falls under the Injury, poisoning and certain other consequences of external causes (S00-T88) classification. It is a non-billable category header code. A more specific child code from the list below must be used for billing and reimbursement purposes.

This is a 7-character code at the 6th level of specificity. There are 3 more specific child codes under S66.305.

Frequently Asked Questions

What is ICD-10 code S66.305?

ICD-10-CM code S66.305 is "Unspecified injury of extensor muscle, fascia and tendon of left ring finger at wrist and hand level". It belongs to the category: Injury, poisoning and certain other consequences of external causes (S00-T88).

Is S66.305 a billable ICD-10 code?

No, S66.305 is a non-billable header code. A more specific child code must be used for billing.

Can S66.305 be coded with other codes?

S66.305 has 2 Excludes2 note(s). These conditions can be coded together if both are documented in the patient record.

Related Codes in S66.30

Other codes in the same category that may be relevant for differential coding:

S66.300Unspecified injury of extensor muscle, fascia and tendon of right index finger at wrist and hand levelS66.301Unspecified injury of extensor muscle, fascia and tendon of left index finger at wrist and hand levelS66.302Unspecified injury of extensor muscle, fascia and tendon of right middle finger at wrist and hand levelS66.303Unspecified injury of extensor muscle, fascia and tendon of left middle finger at wrist and hand levelS66.304Unspecified injury of extensor muscle, fascia and tendon of right ring finger at wrist and hand levelS66.306Unspecified injury of extensor muscle, fascia and tendon of right little finger at wrist and hand levelS66.307Unspecified injury of extensor muscle, fascia and tendon of left little finger at wrist and hand levelS66.308Unspecified injury of extensor muscle, fascia and tendon of other finger at wrist and hand levelS66.309Unspecified injury of extensor muscle, fascia and tendon of unspecified finger at wrist and hand level

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Code Information

CodeS66.305
BillableNo — Header code
ParentS66.30
CategoryInjury, poisoning and certain other consequences of external causes (S00-T88)
Excludes10 rule(s)
Excludes22 note(s)
Child codes3

Data Source

CMS ICD-10-CM 2026 Tabular List

Updated October 1, 2025 (FY2026)