Inferior rectus muscle entrapment, unspecified eye

This code describes a condition where the inferior rectus muscle, responsible for downward movement of the eye, becomes trapped or restricted. This entrapment typically results from trauma, such as an orbital floor fracture, leading to impaired eye movement and potential diplopia.

Use this code when documentation clearly indicates entrapment of the inferior rectus muscle without specifying laterality. This diagnosis is often supported by imaging studies (e.g., CT scan) showing muscle incarceration within a fracture site, along with clinical findings of restricted upgaze or downgaze.

• Ensure documentation specifies "unspecified eye" if laterality is not documented. If laterality is known, use the more specific H50.631 (right eye) or H50.632 (left eye).
• This code is often a secondary diagnosis following an orbital fracture (e.g., S02.3xx).
• Differentiate from other causes of restricted eye movement, such as nerve palsies or thyroid eye disease, which have different ICD-10-CM codes.