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Hypoglossal nerve

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noun, plural: hypoglossal nerves

The cranial nerve that innervates the muscles of the tongue (except for the palatoglossus), and is involved in controlling various tongue movements such as speech and swallowing


Cranial nerves are paired nerves that emerge from the brain and the brainstem. They supply the motor pathways between organs in the face and the upper body, and account for detecting and processing various sensations. One of the cranial nerves is the hypoglossal nerve, which is also referred to as the twelfth cranial nerve or cranial nerve XII (CN XII).

In humans and other vertebrates, the hypoglossal nerve is a pair of cranial nerves that innervates the muscles of the tongue, except for the palatoglossus. The vagus nerve is the one that innervates the palatoglossus.

Lesions of the twelfth nerve may result in the deviation of the tongue toward the paralysed side and thick speech. When the upper motor neuron is damaged, the outcome may be the weakness of the innervated muscles. When the lower motor neuron is damaged, the possible outcome is atrophy of the muscles of the tongue or fasciculations.


  • cranial nerve XII (CN XII)
  • twelfth cranial nerve

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