XII-Hypoglossal

 The twelfth nerve - the Hypoglossal nerve is motor in function.

Innervation

• Intrinsic and extrinsic muscles of the tongue

Function

• Movement of the tongue.

Click here to see an image showing the distribution of the hypoglossal nerve

Anatomy

The axons originate in the hypoglossal nucleus, travel ventrally through the medulla and exit between the pyramid and olive by a series of rootlets.

The hypoglossal nerve exits the skull via the hypoglossal canal.                                                         

Afferents from the nuclear solitarius and the trigeminal sensory nucleus also enter the hypoglossal nucleus, and are important in chewing, sucking, and swallowing. The hypoglossal nucleus also receives corticobulbar fibres from the opposite motor cortex and is involved with speech.

 Image courtesy of https://en.wikipedia.org/wiki/Image:Gray130.png