Which cranial nerve is responsible for both sensory and motor functions related to facial structures?

The trigeminal nerve, or cranial nerve V, is indeed responsible for both sensory and motor functions associated with facial structures. This nerve has three major branches: the ophthalmic, maxillary, and mandibular branches. The sensory functions of the trigeminal nerve include sensation from the skin of the face, the mucous membranes of the nose and mouth, and the teeth. It provides crucial sensory input necessary for facial awareness and protection.

In addition to its sensory capabilities, the trigeminal nerve also carries motor fibers that innervate the muscles of mastication, which are essential for chewing. This dual role makes it unique among cranial nerves, as it effectively combines sensory and motor functions in relation to the face.

Other cranial nerves listed serve different functions. The abducens nerve is primarily a motor nerve that innervates the lateral rectus muscle controlling lateral eye movement. The optic nerve is solely a sensory nerve responsible for vision, conveying visual information from the retina to the brain. Similarly, the vestibulocochlear nerve is a sensory nerve that manages hearing and balance, with no motor functions associated with facial structures. Thus, the trigeminal nerve stands out as the correct answer due to its comprehensive involvement in both sensory