<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> The hypoglossal nerve is the twelfth cranial nerve, and innervates all the extrinsic and intrinsic muscles of the tongue, except for the palatoglossus which is innervated by the vagus nerve . It is a nerve with a solely motor function . The nerve arises from the hypoglossal nucleus in the brain stem as a number of small rootlets, passes through the hypoglossal canal and down through the neck, and eventually passes up again over the tongue muscles it supplies into the tongue . There are two hypoglossal nerves in the body: one on the left, and one on the right . </P> <P> The nerve is involved in controlling tongue movements required for speech and swallowing, including sticking out the tongue and moving it from side to side . Damage to the nerve or the neural pathways which control it can affect the ability of the tongue to move and its appearance, with the most common sources of damage being injury from trauma or surgery, and motor neuron disease . The first recorded description of the nerve is by Herophilos in the third century BC . The name hypoglossus springs from the fact that its passage is below the tongue, from hypo (Greek: "under") and glossa (Greek: "tongue"). </P>

Several cranial nerves innervate structures of the tongue