Your cranial nerves are imperative to how your neck, head, and face function. Any damage to these 12 nerves could have a great impact on your day-to-day life.

Next, test the function of all 12 cranial nerves. Cranial-nerve lesions can affect one or both sides of the body, so it is important to examine each side and compare the results.

Some cranial nerves also contribute to voluntary and involuntary muscle movements. The trochlear nerve, also known as cranial nerve 4 (CN IV ), controls the superior oblique muscle in your eye.