Which cranial nerve is involved in Bell palsy?

Which cranial nerve is involved in Bell palsy?

• A. Facial Nerve (CN VII)
• B. Trigeminal Nerve (CN V)
• C. Vagus Nerve (CN X)
• D. Olfactory Nerve (CN I)

Answer: (A)

Bell palsy involves acute unilateral weakness of the muscles of facial expression due to a lesion of the facial nerve (CN VII). The facial nerve is responsible for innervating the muscles that move the face, and when it is inflamed or compressed, it causes weakness on the same side of the face, including trouble closing the eye and drooping of the mouth. This is distinct from issues caused by other cranial nerves listed: the trigeminal nerve handles facial sensation and muscles of mastication, the vagus nerve governs many pharyngeal and laryngeal muscles plus autonomic functions, and the olfactory nerve is involved in sense of smell. In Bell palsy the pattern is a lower motor neuron problem affecting the entire ipsilateral face, unlike an upper motor neuron stroke where forehead movement is often preserved due to bilateral cortical input.

Bell palsy involves acute unilateral weakness of the muscles of facial expression due to a lesion of the facial nerve (CN VII). The facial nerve is responsible for innervating the muscles that move the face, and when it is inflamed or compressed, it causes weakness on the same side of the face, including trouble closing the eye and drooping of the mouth. This is distinct from issues caused by other cranial nerves listed: the trigeminal nerve handles facial sensation and muscles of mastication, the vagus nerve governs many pharyngeal and laryngeal muscles plus autonomic functions, and the olfactory nerve is involved in sense of smell. In Bell palsy the pattern is a lower motor neuron problem affecting the entire ipsilateral face, unlike an upper motor neuron stroke where forehead movement is often preserved due to bilateral cortical input.