Quiz Form

Question Date: 17/11/2023

Question: A 42-year-old man develops vertical diplopia, which seems worst when watching television from bed. On examination, he has left hypertropia, which is exacerbated with downward gaze of an adducted left eye. If he tilts his head to the right, the vision improves. Which of the following is the affected cranial nerve?

Options:

Right oculomotor nerve
Left abducens nerve
Left trochlear nerve
Right trochlear nerve

Correct Answer: Left trochlear nerve

Explaination: The trochlear nerve innervates the superior oblique muscle, whose job is to abduct, depress, and intort the eye. With trochlear nerve palsy, patients generally have vertical diplopia that is worsened by looking down the nosewatching television from bed or descending stairs. Resting gaze tends to have hypertropia ipsilateral to the affected eye. The Bielschowsky head tilt test may also help localize the affected nerve, as tilting the head away from the affected eye leads to globe extorsion and correction of the diplopia. Individuals with chronic trochlear nerve palsy may have a chronic head tilt as an unconscious compensatory movement