Facial Paralysis

The facial nerve (CN VII) provides somatic innervation to the facial and peri-ocular muscles, notably to the orbicularis oculi muscle (which mediates eyelid closure) via it’s auriculopalpebral branch. Interruption of innervation may result in any combination of a widened palpebral fissure, a diminished or absent palpebral reflex, deviation of the nasal planum and or drooping of the upper and/or lower lips. Symptoms are more commonly unilateral. Inability to effectively close the eyelids, results in exposure keratopathy, which may progress to ulcerative and/or perforating keratitis.