Magnetic resonance imaging of the oculomotor nerve.

Oculomotor/cranial nerve III palsy is caused by numerous etiologies involving the brainstem, subarachnoid space, cavernous sinus or superior orbital fissure or orbit. Magnetic resonance imaging (MRI) is the most suitable neuro-imaging technique in patients with this presentation to rule out a mass, aneurysm or ischemic vasculopathy. A pictorial review of various pathologies affecting the oculomotor nerve is presented along with their MRI morphology.