Abducens nerve root (CN VI)

Radix nervi abducentis

NervousOrgansHead

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What it is
Leaves the front of the brainstem at the pontomedullary junction, close to the midline above the pyramid. Shown as a short stub on both sides; the nerve continues in the peripheral nervous system.
Function
Motor to the lateral rectus, which turns the eye outward.
Size
Stub about 1 cm; root 1.6 mm thick
Clinical note
Its long climb over the petrous apex makes it a false-localising sign: raised intracranial pressure from any cause can paralyse it.

Nearby nervous structures Accessory nerve root (CN XI), Facial nerve root (CN VII), Glossopharyngeal nerve root (CN IX), Hypoglossal nerve root (CN XII), Medulla oblongata, Oculomotor nerve root (CN III), Pons, Trigeminal nerve root (CN V), Vagus nerve root (CN X), Vestibulocochlear nerve root (CN VIII)