ICD-10 Code H50.639 – Inferior rectus muscle entrapment, unspecified eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H50.639 – Inferior rectus muscle entrapment, unspecified eye
What it is
This code identifies entrapment of the inferior rectus muscle in an unspecified eye. Use it when documentation states the muscle is trapped, but the eye side is not specified.
Clinical signs
Typical findings include restricted upward gaze, diplopia, and orbital pain after trauma or fracture. Clinical features vary; refer to documentation.
When to use this code
Use H50.639 when the record clearly documents inferior rectus muscle entrapment and does not identify right or left eye. It may appear in emergency, ophthalmology, or maxillofacial notes after orbital injury or surgery. Check documentation for laterality if available.
Do not use for
Do not use this code for general strabismus, isolated diplopia, or orbital fracture without documented muscle entrapment. If the side is specified, use the laterality-specific code instead.
Coding tip
Confirm both the trapped muscle and the unspecified eye before assigning H50.639.