Injury to trochlear nerve

This code signifies damage or trauma to the trochlear nerve (cranial nerve IV), which is responsible for innervating the superior oblique muscle of the eye. Injury to this nerve typically results in impaired downward and outward eye movement, often leading to vertical diplopia (double vision).

This code is appropriate for documenting a diagnosed injury to the trochlear nerve, whether due to direct trauma, compression, or other etiologies. Documentation should clearly state the involvement of the trochlear nerve, often evidenced by clinical findings such as vertical diplopia or specific ophthalmological examination results.

• Differentiate from other cranial nerve palsies; ensure documentation specifically points to the trochlear nerve.
• Consider an E-code to identify the external cause of injury, if applicable.
• Review for laterality if specified in the clinical documentation (e.g., right, left, or bilateral).