If you have a patient come in complaining of new or acute onset of unilateral facial paralysis without any other sensory or motor deficits i. Have the patient attempt to raise both eyebrows as if surprised. Then have the patient smile. Bell's palsy also called idiopathic facial paralysis is the most common cause of unilateral facial paralysis. It has the following features:. While the exact cause is unknown, it appears that viral infection herpes virus is associated.
NCBI Bookshelf. Dominika Dulak ; Imama A. Authors Dominika Dulak 1 ; Imama A. Naqvi 2. It arises from the brain stem and extends posteriorly to the abducens nerve and anteriorly to the vestibulocochlear nerve.
NCBI Bookshelf. Boston: Butterworths; The motor portion, or the facial nerve proper, supplies all the facial musculature. The principal muscles are the frontalis, orbicularis oculi, buccinator, orbicularis oris, platysma, the posterior belly of the digastric, and the stapedius muscle.
Patient information: See related handout on Bell's palsy , written by the authors of this article. Bell's palsy is a peripheral palsy of the facial nerve that results in muscle weakness on one side of the face. Affected patients develop unilateral facial paralysis over one to three days with forehead involvement and no other neurologic abnormalities. Symptoms typically peak in the first week and then gradually resolve over three weeks to three months.