S66.421A
✓ BillableLaceration of intrinsic muscle, fascia and tendon of right thumb at wrist and hand level, initial encounter
Injury, poisoning and certain other consequences of external causes (S00-T88)
⚠️ Excludes2
inheritedRules inherited from parent codes.
- • sprain of joints and ligaments of wrist and hand (S63.-)
Clinical Description
ICD-10-CM code S66.421A represents laceration of intrinsic muscle, fascia and tendon of right thumb at wrist and hand level, initial encounter. This code falls under the Injury, poisoning and certain other consequences of external causes (S00-T88) classification. It is a billable/specific code valid for HIPAA-covered transactions as of October 1, 2025 (FY2026). This code can be used to indicate a diagnosis for reimbursement purposes on insurance claims.
This is a 8-character code at the 7th level of specificity. This is the most specific code available in this subcategory.
Frequently Asked Questions
What is ICD-10 code S66.421A?
ICD-10-CM code S66.421A is "Laceration of intrinsic muscle, fascia and tendon of right thumb at wrist and hand level, initial encounter". It belongs to the category: Injury, poisoning and certain other consequences of external causes (S00-T88).
Is S66.421A a billable ICD-10 code?
Yes, S66.421A is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
Can S66.421A be coded with other codes?
S66.421A has 1 Excludes2 note(s). These conditions can be coded together if both are documented in the patient record.
Related Codes in S66.421
Other codes in the same category that may be relevant for differential coding:
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Data Source
CMS ICD-10-CM 2026 Tabular List
Updated October 1, 2025 (FY2026)