Bell's Palsy is a disorder of which nerve?

• A. The seventh cranial nerve (facial nerve)
• B. The fifth cranial nerve (trigeminal nerve)
• C. The optic nerve (cranial II)
• D. The hypoglossal nerve (cranial XII)

Answer: (A)

Bell's Palsy involves the facial nerve, the seventh cranial nerve, which is responsible for innervating the muscles of facial expression. When this nerve is affected, signaling to the facial muscles on one side is disrupted, causing sudden weakness or paralysis of that side of the face—often with an inability to close the eye, drooping of the mouth, and lack of forehead movement. Additional signs can include changes in taste from the anterior two-thirds of the tongue and, less commonly, sensitivity to sound due to stapedius muscle involvement. This pattern fits Bell's Palsy and distinguishes it from issues caused by other nerves: the trigeminal nerve would affect facial sensation and chewing, the optic nerve handles vision, and the hypoglossal nerve controls tongue movement.