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 rationale

While individuals aged 19 to 30 years are generally at a lower risk for malignant melanoma compared to older adults, melanoma can still occur at any age, especially with certain risk factors. However, age alone does not significantly increase the risk of developing malignant melanoma without additional risk factors.

Choice B rationale

Hair color has minimal impact on the risk of developing malignant melanoma. Although individuals with fair skin and light hair have a higher risk of sunburn and subsequent melanoma, having dark hair does not significantly reduce the risk compared to other factors.

Choice C rationale

Female gender does not inherently increase the risk of developing malignant melanoma. Both males and females are at risk, although certain lifestyle factors and behaviors, such as sun exposure, can influence individual risk levels regardless of gender.

Choice D rationale

A history of repeated sunburn significantly increases the risk of developing malignant melanoma. Ultraviolet (UV) radiation from sunburns causes DNA damage in skin cells, leading to mutations that can result in melanoma. Repeated sunburns exacerbate this risk, making it a critical factor in melanoma development.

Choice A rationale

The 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 rationale

The 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 rationale

The 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 rationale

The 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.