During cranial nerve assessment, sticking out the tongue and moving it from side to side tests which nerve?

During cranial nerve assessment, sticking out the tongue and moving it from side to side tests which nerve?

• A. Cranial Nerve V (CN V)
• B. Cranial Nerve VII (CN VII)
• C. Cranial Nerve IX (CN IX)
• D. Cranial Nerve XII (CN XII)

Answer: (D)

The movement of sticking out the tongue and moving it side to side mainly tests the motor function of the tongue via the hypoglossal nerve. This nerve innervates the intrinsic tongue muscles and the extrinsic muscles that control tongue movement, especially the genioglossus, which protrudes the tongue. When you have the patient protrude the tongue, you’re checking for symmetric strength and any signs of weakness, atrophy, or fasciculations. If there’s a lesion on one side, the tongue tends to deviate toward the weaker (affected) side when protruded because the genioglossus on that side cannot push the tongue straight. The other nerves listed don’t govern tongue protrusion: the trigeminal nerve is mainly about jaw muscles and facial sensation, the facial nerve controls facial expressions, and the glossopharyngeal nerve handles swallowing and posterior tongue sensation. Thus, this particular tongue movement exam specifically assesses the hypoglossal nerve.

The movement of sticking out the tongue and moving it side to side mainly tests the motor function of the tongue via the hypoglossal nerve. This nerve innervates the intrinsic tongue muscles and the extrinsic muscles that control tongue movement, especially the genioglossus, which protrudes the tongue. When you have the patient protrude the tongue, you’re checking for symmetric strength and any signs of weakness, atrophy, or fasciculations. If there’s a lesion on one side, the tongue tends to deviate toward the weaker (affected) side when protruded because the genioglossus on that side cannot push the tongue straight. The other nerves listed don’t govern tongue protrusion: the trigeminal nerve is mainly about jaw muscles and facial sensation, the facial nerve controls facial expressions, and the glossopharyngeal nerve handles swallowing and posterior tongue sensation. Thus, this particular tongue movement exam specifically assesses the hypoglossal nerve.