Case 2

A 43-year-old man presents complaining of double vision when he looks down. This started yesterday after he was hit in the right eye by a squash ball.

On examination, he has bruising around the eye and a subconjunctival haemorrhage. Visual acuity and pupil reaction are both normal. There is no tethering of upward gaze and infraorbital nerve sensation is intact.

CT scan shows a fracture involving the superior orbital fissure. There is no associated intracerebral haemorrhage.

Which cranial nerve is involved?

Apart from trauma, what other aetiologies may cause a CN IV palsy?

Select one or more options.

What are the benefits of sending this patient for a CT scan rather than a normal x-ray?

See if you can list at least three things here.