Which cranial nerve is primarily responsible for facial sensations?

The trigeminal nerve (CN V) is primarily responsible for facial sensation because it is the main sensory nerve for the face. It has three major branches—ophthalmic, maxillary, and mandibular—that transmit sensory information from various regions of the face to the brain. This nerve provides the ability to perceive touch, pain, temperature, and proprioception from the skin of the face, as well as from the mucous membranes of the oral and nasal cavities.

The facial nerve (CN VII) primarily controls the muscles of facial expression and provides some taste sensation from the anterior two-thirds of the tongue, but it does not significantly contribute to facial sensation. The glossopharyngeal nerve (CN IX) is mainly involved in taste and sensation from the posterior one-third of the tongue and the pharynx, while the accessory nerve (CN XI) primarily innervates the sternocleidomastoid and trapezius muscles, playing no role in facial sensation. Thus, the trigeminal nerve clearly fulfills the function of conveying facial sensations.