Which cranial nerve is primarily responsible for facial sensation and chewing?

• A. I Olfactory
• B. V Trigeminal
• C. VII Facial
• D. XI Spinal Accessory

Answer: (B)

The main idea here is how facial sensation and chewing are controlled by the nervous system. The nerve responsible is the trigeminal nerve, the fifth cranial nerve, because it handles most of the face’s sensation and also supplies the muscles used for chewing.

Its three branches cover all regions of the face: V1 goes to the forehead and scalp, V2 to the midface and cheeks, and V3 to the jaw and lower face. The motor fibers in the mandibular branch (V3) innervate the muscles of mastication—masseter, temporalis, and the pterygoids—allowing chewing. So this nerve uniquely combines facial sensory input with motor control of chewing, making it the correct choice.

In contrast, the olfactory nerve is for smell, the facial nerve mainly controls facial expression and taste on the front part of the tongue, and the spinal accessory nerve moves neck muscles.