If a patient has tongue motor impairments that show ipsilateral wasting and deviation, which cranial nerve is likely involved?

The correct answer is the Hypoglossal Nerve, which is designated as Cranial Nerve XII. This nerve is primarily responsible for motor function of the tongue. When there is impairment in the Hypoglossal Nerve, it can lead to symptoms such as ipsilateral wasting of the tongue muscles and deviation of the tongue towards the affected side during protrusion.

Ipsilateral wasting means that the muscle tissue on the same side as the affected nerve appears reduced in size, indicating atrophy due to lack of innervation. When the tongue is protruded, it deviates towards the side of the nerve damage because the muscle on the unaffected side is stronger and pulls the tongue over.

The involvement of the other cranial nerves listed is unlikely concerning tongue motor impairment as described. The Vagus Nerve (Cranial Nerve X) primarily controls muscles involved in phonation and the soft palate, while the Glossopharyngeal Nerve (Cranial Nerve IX) contributes to taste and some swallowing functions, but does not directly control tongue movement. The Spinal Accessory Nerve (Cranial Nerve XI) predominantly innervates the sternocleidomastoid and trapezius muscles, having no direct effect