Which cranial nerve provides sensory innervation to the face via its three divisions?

• A. CN V
• B. CN VII
• C. CN IX
• D. CN X

Answer: (A)

The main idea is that facial sensation is carried by the trigeminal nerve, which is the primary sensory nerve of the face and splits into three divisions that cover the entire face. These divisions are the ophthalmic, maxillary, and mandibular nerves. The ophthalmic branch supplies the forehead, scalp, upper eyelid, and cornea; the maxillary branch supplies the midface, cheeks, upper lip, upper teeth, and palate; the mandibular branch supplies the lower face, lower lip, and lower teeth (and also carries sensation from parts of the tongue). Together, they give the comprehensive sensory map of the face.

The other nerves listed don’t provide face sensation through three divisions: the facial nerve mainly handles facial expression and some taste; the glossopharyngeal and vagus nerves handle taste and sensory information in the oropharyngeal region and visceral areas rather than the face. Hence, the nerve that provides sensory innervation to the face via its three divisions is the trigeminal nerve.