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, transmitting visual information from the retina to the brain. Dysfunction of the optic nerve would result in visual disturbances, such as loss of vision or changes in visual acuity, rather than difficulty with tongue movement. This nerve does not control motor functions of the tongue.Choice B rationaleThe abducens nerve (CN VI) controls the lateral rectus muscle of the eye, which is responsible for moving the eye outward, away from the nose. Dysfunction of the abducens nerve would result in issues with eye movement, such as double vision or inability to move the eye laterally, not tongue movement. It does not play a role in tongue motor control.Choice C rationaleThe hypoglossal nerve (CN XII) controls the muscles of the tongue, enabling movements necessary for speech, swallowing, and mastication. Dysfunction of this nerve would result in difficulty protruding the tongue and reduced strength during resistance testing. Symptoms can include atrophy of the tongue muscles, fasciculations, and deviation of the tongue to one side when extended.Choice D rationaleThe vestibulocochlear nerve (CN VIII) is responsible for hearing and balance, transmitting sound and equilibrium information from the inner ear to the brain. Dysfunction of the vestibulocochlear nerve would lead to symptoms such as hearing loss, tinnitus, or balance disorders like vertigo. It does not affect the motor control of the tongue.