Cranial nerve · one in each half of the brain
Trigeminal nerve (V)
Also called Cranial nerve V, CN V, Fifth nerve
The face's feeling nerve: touch, pain, and heat from your whole face, plus chewing.
The trigeminal is the biggest cranial nerve. It splits into three branches that cover your forehead, your cheek and upper jaw, and your lower jaw. It lets you feel a kiss, a breeze, a hot drink, or a toothache. It also powers the strong muscles you chew with.
Where it is
It leaves the side of the pons, the bulge in the middle of the brainstem. Its three branches spread out from a knot of nerve cells on the floor of the skull and fan across the face.
What it does
Feeling the face
It carries touch, pain, and temperature from your skin, eyes, nose, mouth, gums, and teeth.
Chewing power
Its lower branch works the powerful jaw muscles. Clench your teeth and feel them bulge at your temples and jaw.
Blink protection
If something touches the surface of your eye, it senses it instantly and triggers a protective blink.
Spicy and cool
It lets you feel the burn of chili and the cool of mint in your mouth and nose.
Think of it as a three-pronged cable fanning out to three floors of the face: the forehead on top, the cheeks in the middle, and the jaw at the bottom.
Works with
- PonsIts main control centers sit in the pons, where it enters the brainstem.
- Ventral posterior nucleus of the thalamusFace sensations pass through this relay station in the thalamus on the way to the cortex.
- Primary somatosensory cortexSignals end up in the face area of your touch map, which is extra large because the face is so sensitive.
- Facial nerve (VII)In the blink reflex, the trigeminal feels the touch and the facial nerve closes the eyelids.
- Spinal cordIts pain and temperature fibers take a surprising detour down into the top of the spinal cord before heading back up.
When it goes wrong
How doctors check it
With your eyes closed, the doctor lightly touches your forehead, cheek, and chin on both sides and asks if they feel the same. Then you clench your jaw while they feel the muscles.
Trigeminal neuralgia
Sudden, electric-shock stabs of pain on one side of the face, set off by light touches like brushing teeth, shaving, or a breeze. It is often caused by a blood vessel pressing on the nerve, and medicines or surgery can help.
Numb at the dentist
The injection that numbs your lower teeth blocks a branch of this nerve. That is why your lip and chin feel fat and numb for hours afterward.
For learning only, not medical advice. If you have a health concern, talk to a doctor.
Surprising facts
- Migraine pain is thought to be carried largely by trigeminal fibers around blood vessels in the brain's coverings. Some newer migraine medicines work by blocking a chemical these fibers release.
- Shingles, a reawakened chickenpox virus, can hide in this nerve for many years and later flare up as a painful rash on one side of the face.
By the numbers
Where the name comes from
From the Latin trigeminus, "born as triplets" (tri, "three", and geminus, "twin"), because it splits into three branches.
Learn it in a lesson
- The brainstem and cranial nervesLife support and the nerves of the head. A short guided lesson in 3D.
Quick quiz
3 questions. Your answers are saved and come back in your daily review.
Which of these is a job of the trigeminal nerve (V)?
Show the answer
Feeling the face. It carries touch, pain, and temperature from your skin, eyes, nose, mouth, gums, and teeth.
Feeling the face. It carries touch, pain, and temperature from your skin, eyes, nose, mouth, gums, and teeth.
The trigeminal nerve (V) 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 three-pronged cable fanning out to three floors of the face: the forehead on top, the cheeks in the middle, and the jaw at the bottom."
Show the answer
Trigeminal nerve (V). It is the trigeminal nerve (V). The face's feeling nerve: touch, pain, and heat from your whole face, plus chewing.
Trigeminal nerve (V). It is the trigeminal nerve (V). The face's feeling nerve: touch, pain, and heat from your whole face, plus chewing.
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 5 (Trigeminal), StatPearls, NCBI Bookshelf
- Trigeminal Neuralgia, National Institute of Neurological Disorders and Stroke (NINDS)
- Migraine, Radiopaedia
Spotted a mistake? Tell us.
Explore the trigeminal nerve (V) in 3D
Turn it around, zoom inside and see how it connects to the rest of the brain, then test yourself with quick quizzes.
Open it in 3D