On assessment of the client's tongue, the client is unable to protrude the tongue and has poor strength on testing against resistance.This would indicate dysfunction of which cranial nerve?

Choice A rationaleThe optic nerve (CN II) is responsible for vision. It transmits visual information from the retina to the brain. Dysfunction in this nerve typically results in visual disturbances such as loss of vision, visual field defects, or difficulty in distinguishing colors. It does not control the movement or strength of the tongue.Choice B rationaleThe abducens nerve (CN VI) innervates the lateral rectus muscle of the eye, which is responsible for abducting the eye (moving it outward). Dysfunction in this nerve can lead to strabismus (misalignment of the eyes), double vision, or inability to move the eye outward. It does not affect tongue movement or strength.Choice C rationaleThe hypoglossal nerve (CN XII) innervates the muscles of the tongue, controlling its movement and strength. Dysfunction in this nerve can result in difficulty protruding the tongue, poor strength against resistance, and impaired speech or swallowing. Therefore, the symptoms described in the question indicate a dysfunction of the hypoglossal nerve.Choice D rationaleThe vestibulocochlear nerve (CN VIII) is responsible for hearing and balance. It transmits sound and equilibrium information from the inner ear to the brain. Dysfunction in this nerve can lead to hearing loss, tinnitus, vertigo, or balance problems. It does not control tongue movement or strength.