Billable / Specific Code
ICD-10-CM M66.321 is the diagnosis code for Spontaneous rupture of flexor tendons, right upper arm. This code falls under the section "Disorders of synovium and tendon" within Chapter 13 — Diseases of the musculoskeletal system and connective tissue (M00-M99). 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 M66.321 sits in the ICD-10-CM classification helps ensure proper coding:
Yes, M66.321 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
M66.321 is the ICD-10-CM diagnosis code for "Spontaneous rupture of flexor tendons, right upper arm". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
The parent code of M66.321 is M66.32 ("Spontaneous rupture of flexor tendons, upper arm"). M66.321 provides a more specific classification within this category.
M66.321 is located in Section M65-M67 — "Disorders of synovium and tendon" within Chapter 13 of the ICD-10-CM Tabular List.
Use M66.321 when the patients documented diagnosis matches "Spontaneous rupture of flexor tendons, right upper arm" 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 Spontaneous rupture of flexor tendons, right upper arm is M66.321.
Yes, M66.321 can be used as a primary diagnosis code since it is billable and specific.
M66.321 is in Chapter 13 of the ICD-10-CM Tabular List.
Yes, M66.321 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.