Billable / Specific Code
ICD-10-CM S66.409 is the diagnosis code for Unspecified injury of intrinsic muscle, fascia and tendon of unspecified thumb at wrist and hand level. This code falls under the section "Injuries to the wrist, hand and fingers" within Chapter 19 — Injury, poisoning and certain other consequences of external causes (S00-T88). It is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
Always refer to the official ICD-10-CM Tabular List for complete coding guidelines. Ensure documentation supports the specificity of the code selected. When in doubt, consult a certified medical coder or the latest CMS guidelines.
Understanding where S66.409 sits in the ICD-10-CM classification helps ensure proper coding:
Yes, S66.409 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
S66.409 is the ICD-10-CM diagnosis code for "Unspecified injury of intrinsic muscle, fascia and tendon of unspecified thumb at wrist and hand level". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
The parent code of S66.409 is S66.40 ("Unspecified injury of intrinsic muscle, fascia and tendon of thumb at wrist and hand level"). S66.409 provides a more specific classification within this category.
S66.409 is located in Section S60-S69 — "Injuries to the wrist, hand and fingers" within Chapter 19 of the ICD-10-CM Tabular List.
Use S66.409 when the patients documented diagnosis matches "Unspecified injury of intrinsic muscle, fascia and tendon of unspecified thumb at wrist and hand level" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Unspecified injury of intrinsic muscle, fascia and tendon of unspecified thumb at wrist and hand level is S66.409.
Yes, S66.409 can be used as a primary diagnosis code since it is billable and specific.
S66.409 is in Chapter 19 of the ICD-10-CM Tabular List.
Yes, S66.409 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.