Hypoglossal nerve

The hypoglossal nerve is the twelfth and last cranial nerve and supplies the tongue with motor control. It only has one catch: it receives hitch-hiking C1 nerve root fibres, which it distributes before reaching the tongue.

Gross anatomy

The nerve emerges from the medulla laterally, between the pyramid and the olive as a number of rootlets. These join to form two roots, and passing anteriorly, they enter the hypoglossal canal, located between the occipital condyle and jugular tubercle, which runs obliquely forwards (posteromedial to anterolateral), emerging below the base of the skull. Within the canal the two roots join, such that a single nerve arises from it.

It proceeds to run behind the inferior ganglion of the vagus nerve, and then between the internal jugular vein and internal carotid artery until the occipital artery and its branch to sternocleidomastoid that hook over it (laterally). At this point, the nerve runs forwards, with the carotid artery and uppermost loop of the lingual artery located medial to it.

The lingual artery passes medially (deep) to hyoglossus whereas the hypoglossal nerve remains lateral (superficial). From here it gives off its terminal branches that supply all the muscles of the tongue except for palatoglossus.

Branches

Neuroanatomy
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Article Information

rID: 1483
Section: Anatomy
Tag: refs
Synonyms or Alternate Spellings:
  • Hypoglossal nerve (CN XII)
  • Hypoglossal nerve (XII)

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