Twelve cranial nerves

There are twelve pairs of cranial nerves that emerge directly from the base of the brain. There are 31 pairs of spinal nerves.
The cranial nerves mainly connect the brain to the head and neck region. The spinal nerves continue to split into branches throughout the body.


The numbering of the cranial nerves is related to the order in which they arise from the brain stem. The numbering runs from front to back.


Roman numerals
The cranial nerves are numbered with Roman numerals. I =1, II =2, III =3, IV = 4, V =5, VI =6, VII =7, VIII =8, IX =9, X =10, XI =11, XII =12.


The abbreviation for a nerve is N from the Latin word nervus.
Sometimes the abbreviation CN is used. This is the abbreviation for cranial nerve. For example, CN X is the 10th cranial nerve or vagus nerve.


N I Nervus Olfactorius - olfactory nerve

Olfactory nerve transmits information about smell to the brain. It is the shortest and oldest nerve of the twelve cranial nerves.

N II Nervus Opticus - optic nerve

Second cranial nerve. This nerve carries information from the photoreceptors to the brain. So it concerns visual stimuli. From the optic disc where the nerve fibers come together it forms the optic nerve.

N III Nervus Oculomotor - eye movement nerve

Third cranial nerve. This nerve has two nuclei, the somatic and the visceral efferent motor nerve. It is the main nerve for the control of the eye. It controls four of the six external eyeball muscles. It also ensures that the pupil size is adjusted to the amount of light.

N IV Nervus Trochlearis - external optic nerve

fourth cranial nerve. This nerve plays a role in eye movements by supplying the outer oblique muscles of the eye (extraocular muscles or extrinsic ocular muscles).

There are six extraocular muscles: four recti-(straight) and the superior and the inferior oblique muscles:

  • m rectus inferior
  • m rectus superior
  • m rectus lateralis
  • m rectus medialis
  • m obliquus inferior
  • m obliquus superior

Together they control the movements of the eyeball.


N V Nervus Trigeminus - trigeminal nerve

As the name suggests, this nerve consists of three parts. It transmits emotional information from the head and face to the brain. It provides information to the chewing muscles. It tenses the eardrum and palate and perceives the sensations of the face and mucous membranes.

  1. Nervus Ophthalmic / optic nerve (CN V1) - sensation of the skin of the forehead, eye socket, eyelids, eyebrows, nose and nasal cavity
  2. Nervus Maxillaris / maxillary nerve (CN V2) - sensation of the lower eyelid, cheek, upper lip, upper jaw, around the cheekbone, nose, gums, teeth and molars
  3. Nervus Mandibularis mandibular nerve (CN V3) - the skin of the mouth (buccal skin), teeth, salivary glands, anterior part of the tongue, lower lip, skin of temples and lower jaw

N VI Nervus Abducens - abducens nerve

sixth cranial nerve. This nerve controls the lateral rectus muscle (lateral extraocular rectus muscle), which allows the eye to turn outward.

N VII Nervus Facialis - facial nerve

seventh cranial nerve. This is a mixed nerve of the face.

  • The sensory (or sensitive) nerves transmit information about pressure differences or pressure sensations in the face.
  • They transmit sensory information of taste from the front 2/3 of the tongue.
  • The movement (motor) nerves control facial expressions. They also control the salivary and lacrimal glands.

N VIII Nervus Vestibulocochlearis - auditory and balance nerve

The eighth cranial nerve is a special somatic afferent nerve. It consists of two parts:

  • The vestibular nerve provides balance and movement, equilibrium information, the position and movement of the head.
  • The cochlear nerve ensures that we can hear.

This nerve is important for balance and orientation in space.

N IX Nervus Glossopharyngeus - glossopharyngeal nerve

The ninth cranial nerve. This nerve provides sensory information from the taste buds and allows a person to taste something. It transmits motor information to the neck muscles to enable swallowing. It controls salivary glands for saliva secretion. It provides visceral and general sensation in the oral cavity.

N X Nervus Vagus - vagus nerve

tenth cranial nerve. Vagus nerve. Sometimes called parasympathetic nerve.
It is the longest cranial nerve of the 12 cranial nerves. It descends through the neck and neck into the chest and abdominal cavities.
The vagus nerve conveys information about the condition of the organs to the brain. And conversely, it also sends signals to the various organs of the body and plays a major role in many different functions in the body.
For example, it regulates part of the external acoustic auditory canal (hearing), dura mater of the posterior cranial fossa, the control of the palate, the pharynx and the larynx and thus swallowing and tasting. It regulates autonomic functions such as heart rate,
blood pressure, breathing, digestion and bladder function.

It regulates the muscle control of the bronchi, lungs, vocal cords, glandular secretions, muscle control of the tongue and various muscles of the
soft palate, the pharynx and the larynx and vocal cords. It controls the movement of food (peristalsis) from the stomach to the left flexure of the large intestine and controls other abdominal organs such as the liver, spleen, pancreas, etc.

Involved in:

  • Hard meninges
  • External acoustic meatus
  • Tongue
  • Pharynx
  • Vocal cords
  • Esophagus
  • Larynx
  • Trachea
  • Tracheal branch / airway branch
  • Breathing
  • Heart
  • Blood pressure
  • Stomach
  • Liver
  • Pancreas
  • Spleen
  • Intestines
  • Inflammation
  • Pain and pain regulation
  • Mood and stress levels

The vagus nerve also regulates the parasympathetic nervous system, which can put the body in a state of rest and recovery. It can slow the heart rate and lower blood pressure and stimulate digestion.
It thus regulates stress levels.
The vagus nerve has four vagal nuclei that monitor the cardiovascular (heart and blood vessels), respiratory (breathing) and nutritional systems (digestion and glandular secretions).
Recent studies have shown that this tenth cranial nerve is also involved in inflammation, mood and pain regulation. Stimulation of the vagus nerve or vagal stimulation is the domain of many researchers to see whether relief from complaints can be achieved.

N XI Nervus Accessorius - accessory nerve / spinal nerve

eleventh cranial nerve. accesorius nerve. This nerve controls the turning movements (rotational movements) of the head and shoulders.
Two important muscles are controlled by the accesorius nerve:

  1. the trapezius muscle
  2. the sternum collarbone nipple muscle (sternocleidomastoid muscle) Named after three points to which the muscle is attached. The breastbone (sternum), the collarbone (clavicle) and nipple-shaped protrusion of the temporal bone (mastoid process) near the ear.

The 11th cranial nerve is a branch of the trigeminal nerve and the spinal cord between the first and fourth vertebrae. In case of damage, a person is less able to move their shoulder towards their head and their head is tilted.
The nerve roots that emerge from the cervical spine first form a network (cervical plexus) of nerves in the neck.

N XII Nervus Hypoglossus -- sublingual nerve

This nerve plays a role in controlling the tongue muscles. It is very important for functions such as speech and swallowing.

Tenth cranial nerve or vagus nerve

Vagus nerve is a very versatile cranial nerve. It is also the longest. It runs through the neck and neck to the chest and abdominal cavity.



Motor, sensory or autonomous? Afferent or efferent?

In which direction does the information go? From or to the brain? Or both?

  • If a nerve carries information from the brain to the ends of the body (periphery), it is called an "efferent" (motor) nerve.
    Motor cranial nerves are: N III, IV, V, VI, VII, IX.
  • Conversely, if the information from the body (periphery) goes to the brain, this is an "afferent" (sensory) nerve.
    Sensory cranial nerves are: N I, II, V, VII, VIII, IX.
  • If information goes from the brain to the body and from the body to the brain, it is a mixed/autonomic nerve with combined sensory and motor function.
    Mixed/Autonomic cranial nerves are: N III, VII, IX and X.

Spinal nerves are always mixed nerves.


Visceral efferent nerve

This type of nerve nerve transmits information to smooth muscle, cardiac muscle, or glands. Visceral is often (there are exceptions) synonymous with autonomic in the autonomic nervous system.


Somatic efferent nerve

This type of nerve transmits information to the skin or to the skeletal muscles. General somatic efferent nerve pathways contain information from the proprioception (information about movement and position) of muscles, tendons and joints.



To help you remember the order of the twelve nerves, see for mnemonics here.


What are the consequences of nerve damage?

The explanation of what consequences there may be due to damage to the 12 cranial nerves is explained on our neurological examination page.