Cranial nerve · one in each half of the brain
Abducens nerve (VI)
Also called Cranial nerve VI, CN VI, Sixth nerve
Turns each eye outward, so you can glance to the side without moving your head.
The abducens nerve has one job: it powers the muscle that pulls the eye outward, away from your nose. Without it, you could not glance to the side. It leaves the brainstem low down and climbs a long way along the base of the skull, so rising pressure inside the head can squeeze it.
Where it is
It leaves the brainstem where the pons meets the medulla, then runs a long way up the back of the skull base and forward into the eye socket.
What it does
Outward gaze
It moves the eye outward, toward your ear, using a muscle called the lateral rectus.
Side-to-side teamwork
To look right, the right eye's abducens and the left eye's oculomotor nerve fire together, so both eyes turn the same way at the same moment.
Steady gaze
Balance signals from the inner ear feed into it, helping your eyes stay locked on a target while your head moves.
Think of it as a single rope tied to the outer side of the eyeball: pull it and the eye swings out toward your ear.
Works with
- PonsIts control center sits low in the pons, next to a gaze center that coordinates both eyes.
- Oculomotor nerve (III)It partners with the other eye's oculomotor nerve to make both eyes glance sideways together.
- Trochlear nerve (IV)The three eye-moving nerves share the work of pointing each eye in every direction.
- Vestibulocochlear nerve (VIII)Balance signals from the inner ear steer it, so your eyes counter your head movements automatically.
- Flocculonodular lobeThis part of the cerebellum fine-tunes eye movements so your gaze stays smooth and steady.
When it goes wrong
How doctors check it
You "follow my finger" as it moves out to each side. If one eye cannot turn outward past the middle, this nerve may be affected.
Sixth nerve palsy
The affected eye drifts in toward the nose, and the person sees two images side by side, worse when looking toward the weak side.
A pressure warning
Because of its long path, raised pressure inside the skull, from swelling, bleeding, or a tumor, can stretch it even when the actual problem is far away. Doctors call this a "false localizing sign".
For learning only, not medical advice. If you have a health concern, talk to a doctor.
Surprising facts
- A handy way to remember the eye nerves is "LR6, SO4, the rest are 3": the lateral rectus uses nerve VI, the superior oblique uses nerve IV, and all the other eye muscles use nerve III.
- Children sometimes get a temporary sixth nerve weakness after an ordinary virus, and it usually gets better on its own.
By the numbers
Where the name comes from
From the Latin abducere, "to lead away". It moves the eye away from the middle of the face.
Quick quiz
3 questions. Your answers are saved and come back in your daily review.
Which of these is a job of the abducens nerve (VI)?
Show the answer
Outward gaze. It moves the eye outward, toward your ear, using a muscle called the lateral rectus.
Outward gaze. It moves the eye outward, toward your ear, using a muscle called the lateral rectus.
The abducens nerve (VI) is part of which larger structure?
Show the answer
Cranial nerves. It belongs to the cranial nerves.
Cranial nerves. It belongs to the cranial nerves.
Which part fits this description? "Like a single rope tied to the outer side of the eyeball: pull it and the eye swings out toward your ear."
Show the answer
Abducens nerve (VI). It is the abducens nerve (VI). Turns each eye outward, so you can glance to the side without moving your head.
Abducens nerve (VI). It is the abducens nerve (VI). Turns each eye outward, so you can glance to the side without moving your head.
These parts now come back in your daily review, just before you would forget them.
Practice it and its neighbors in 3DSources
- Neuroanatomy, Cranial Nerve 6 (Abducens), StatPearls, NCBI Bookshelf
- Abducens Nerve Palsy, StatPearls, NCBI Bookshelf
- Neuroanatomy, Abducens Nucleus, StatPearls, NCBI Bookshelf
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