which cranial nerve opens your eyelid
Facial Nerve Injury. The Facial Nerve or the Seventh (7th) Cranial Nerve is responsible for facial and eyelid muscle contraction and movement. If this nerve is injured or dysfunctional, then a facial droop and incomplete eyelid closure may result. This condition is called âFacial Nerve Palsyâ or âSeventh Nerve Palsyâ.
Ptosis is the lagging of an eyelid. It has 2 distinct etiologies. Sympathetics going to the eye innervate Muller's muscle, a small muscle that elevates the eyelid. The III cranial nerve also innervates a much larger muscle that elevates the eye lid: the levator palpebrae. Thus, disruption of either will cause ptosis. The ptosis from a III nerve palsy is of greater severity than the ptosis due to a lesion of the sympathetic pathway, due to the size of the muscles innervated.