The nerve that innervates the tongue protruder is which cranial nerve?

The nerve that innervates the tongue protruder is which cranial nerve?

• A. CN X
• B. CN XII
• C. CN IX
• D. CN V

Answer: (B)

The ability to protrude the tongue comes mainly from the genioglossus muscle. This muscle is innervated by the hypoglossal nerve (cranial nerve XII), which supplies most of the intrinsic tongue muscles and the extrinsic tongue muscles except for a few exceptions. So the nerve that actually innervates the tongue protruder is cranial nerve XII. The other nerves don’t feed the tongue’s protruding action: the vagus nerve supplies the palatoglossus (not the primary protruder), the glossopharyngeal nerve supplies the stylopharyngeus, and the trigeminal nerve provides motor to muscles of mastication and carries general sensation from the anterior two-thirds of the tongue but does not motor innervation to the tongue muscles themselves. If cranial nerve XII were damaged, the tongue would deviate toward the side of the lesion when protruded due to weakness of the genioglossus.

The ability to protrude the tongue comes mainly from the genioglossus muscle. This muscle is innervated by the hypoglossal nerve (cranial nerve XII), which supplies most of the intrinsic tongue muscles and the extrinsic tongue muscles except for a few exceptions. So the nerve that actually innervates the tongue protruder is cranial nerve XII.

The other nerves don’t feed the tongue’s protruding action: the vagus nerve supplies the palatoglossus (not the primary protruder), the glossopharyngeal nerve supplies the stylopharyngeus, and the trigeminal nerve provides motor to muscles of mastication and carries general sensation from the anterior two-thirds of the tongue but does not motor innervation to the tongue muscles themselves. If cranial nerve XII were damaged, the tongue would deviate toward the side of the lesion when protruded due to weakness of the genioglossus.