A 73 year old man who is recovering from surgery on the left carotid artery in his neck. He has slurred speech. On protusion of his tongue, the tip deviated to the left. What is the single most appropriate option?

The key is D. Hypoglossal nerve. [Testing function of the nerve is performed by asked the subject to

stick their tongue straight out. If there is a loss of innervation to one side, the tongue will curve toward

the affected side, due to unopposed action of the opposite genioglossus muscle. If this is the result of

alower motor neuron lesion, the tongue will be curved toward the damaged side, combined with the

presence of fasciculations or atrophy. However, if the deficit is caused by an upper motor neuron lesion,

the tongue will be curved away from the side of the cortical damage, without the presence of

fasciculations or atrophy].