Hypoglossal nerve (CN XII)
On completing this study unit, you will be able to:
- Describe the origin of the hypoglossal nerve and its associated nuclei.
- Understand the course of the hypoglossal nerve.
- Identify the branches of the hypoglossal nerve and their supply areas.
The hypoglossal nerve (CN XII), is primarily a motor nerve which arises as a series of rootlets from the lateral surface of the medulla oblongata, between the pyramid and olive.
It supplies motor innervation to the extrinsic muscles of the tongue with the exception of palatoglossus (i.e. genioglossus, hyoglossus and styloglossus muscles) as well as all of the intrinsic muscles of the tongue (superior longitudinal muscle of tongue, inferior longitudinal muscle of tongue, transverse muscle of tongue and vertical muscle of tongue).
Find out more about the pathway, branches and function of the hypoglossal nerve by watching the video below!
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Take a look at our atlas gallery to further review the course, distribution and supply of the hypoglossal nerve in more detail.
|Structure and features||
Fibers: General somatic efferent (GSE)
Origin: Medulla oblongata (between pyramid and olive)
Exits skull: Hypoglossal canal
Associated nuclei: Nucleus of hypoglossal nerve
|Branches||Lingual branches of hypoglossal nerve
Note that whilst the following branches are given off by the hypoglossal nerve, their fibers originate from the cervical plexus (C1-2):
Superior root of ansa cervicalis
Extrinsic muscles of the tongue: genioglossus, hyoglossus and styloglossus
Intrinsic muscles of the tongue: superior longitudinal lingual, inferior longitudinal lingual, transversus linguae and verticalis linguae muscle