Which symptom results from damage to Cranial Nerve XII?

Damage to Cranial Nerve XII, also known as the hypoglossal nerve, specifically affects the function of the tongue. This nerve is primarily responsible for the motor control of the tongue muscles. When there is damage to this nerve, the most characteristic symptom observed is the deviation of the tongue towards the side of the lesion (ipsilateral side) when the tongue is protruded. This occurs because the muscles on the affected side are weak or paralyzed, leading to an inability to counteract the strength of the muscles on the opposite side, which remain intact.

In contrast, symptoms associated with dysphagia (difficulty swallowing) and hoarseness are more closely related to damage to other cranial nerves, such as the vagus nerve (CN X) and the glossopharyngeal nerve (CN IX). Similarly, diplopia (double vision) and convergence issues pertain to the function of the oculomotor nerve (CN III), which controls eye movements, rather than any functions associated with the hypoglossal nerve. Problems with dry mouth and loss of taste are typically linked to the glossopharyngeal nerve and the facial nerve (CN VII), which innervates the salivary glands and taste sensations from the