Author: Jana Vasković MD•Reviewer: Nicola McLaren MScLast reviewed: December 21, 2021Reading time: 22 minutes


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facial nerve (lateral appropriate view)

You recognize when someone mentions cranial nerves and also you roll your eyes all the means back to your midbrain? We understand that cranial nerves have constantly been a an overwhelming subject among anatomy students. So we’re here to do it simpler for you.

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Cranial nerves anatomy is necessary for virtually any clinical specialty since they regulate so plenty of body functions, such as rolling her eyes as soon as you’re annoyed by something. Therefore let’s break the stigma of lock being hard to understand, and learn this necessary neuroanatomy topic once and for all.

crucial facts about the cranial nerves
meaning A set of 12 peripheral nerves arising from the mind that innervate the frameworks of the head, neck, thorax and abdomen.
Nerves Olfactory nerve (CN I), optic nerve (CN II), oculomotor nerve (CN III), trochlear nerve (CN IV), trigeminal nerve (CN V), abducens nerve (CN VI), face nerve (CN VII), vestibulocochlear nerve (CN VIII), glossopharyngeal nerve (CN IX), vagus nerve (CN X), accessory nerve (CN XI), and hypoglossal nerve (CN XII). Mnemonics: - Oh, Oh, Oh, To Touch And Feel Very Good Velvet, such-A Heaven- On, On, On, They Traveled And Found Voldemort Guarding Very Ancient Horcruxes.
types of nerves - Sensory: Olfactory nerve (CN I), optic nerve (CN II), vestibulocochlear nerve (CN VIII) - Motor: Oculomotor nerve (CN III), trochlear nerve (CN IV), abducens nerve (CN VI), accessory nerve (CN XI), hypoglossal nerve (CN XII). - blended (both): trigeminal nerve (CN V), facial nerve (CN VII), glossopharyngeal nerve (CN IX), vagus nerve (CN X). Mnemonic (by the numerical order): Some Say Money Matters, But My Brother Says Big Brains Matter Most

Contents
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Anatomy

Cranial nerves are the 12 nerves of the peripheral nervous system that arise from the foramina and also fissures the the cranium. Their numerical order (1-12) is identified by their skull leave location (rostral to caudal). All cranial nerves originate from nuclei in the brain. 2 originate indigenous the forebrain (Olfactory and also Optic), one has a nucleus in the spinal cord (Accessory) while the remainder originate native the brainstem.

There"s a LOT come learn around the cranial nerves. You could like to ease yourself right into this topic with our cranial nerves quizzes and also labeling exercises.

Cranial nerves supply sensory and motor information to frameworks of the head and also neck, managing the task of this region. Just the vagus nerve extends past the neck, come innervate thoracic and ab viscera.


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<12 cranial nerves (diagram)>

We’re certain that while analysis textbooks, you encountered through terms such as afferent, efferent, mixed, general, visceral, special, somatic etc, these refer to modalities that the cranial nerves. They often bring confusion, therefore let’s explain them before proceeding.

The role of a nerve is to bring sensory and/or engine information between the body and the brain. If the details goes from the mind to the periphery, then it is one efferent (motor) nerve. If it travel from the periphery to the brain, then it is one afferent (sensory) nerve. Nerves that execute both are blended nerves. Uneven spinal nerves i m sorry are always mixed, cranial nerves have the right to be completely motor, purely sensory or mixed. 

Now let’s understand the terms special, general, somatic and visceral. The details is classified as special if it travel from our distinct senses (vision, smell, taste, hearing and balance), when general describes details to/from everywhere else. The information brought by a nerve is called somatic if the goes to/from the skin and also skeletal muscles, or visceral if it travel to/from our interior organs. 

Combining these categories allows us to define the functional materials of a nerve. Because that example, if the nerve yarn exclusively lug special sensory information, that is called a special afferent nerve. If that carries other species of sensory information, like touch, pressure, pain, temperature, climate it is a general afferent nerve.

If the nerve carries info to smooth muscle, cardiac muscle or glands, then it is a visceral efferent nerve. If that carries information to skin or skeleton muscle, then it is a somatic efferent nerve. Together the hatchet visceral is often a synonym for autonomic (nervous system), keep in mind that general visceral nerves lug autonomic nerve fibers to/from the target organs. The exemption to this space the special visceral efferent nerves, sometime described as branchial efferent (BE). These room motor nerves, called for the embryological beginning of the fibres. Details of movement and also position (proprioception) indigenous somatic structures choose muscles, tendons, and also joints is brought by basic somatic afferent nerves. Lastly, be mindful that over there is no special somatic efferent classification. 

So come conclude, considering the feasible directions and modalities, cranial nerves can be:

General somatic afferent (GSA)General somatic efferent (GSE)General visceral afferent (GVA)General visceral efferent (GVE)Special somatic afferent (SSA)Special visceral afferent (SVA)Special visceral efferent (SVE)

Here is a cranial nerves starter pack for you:


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12 cranial nerves discover study unit
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Cranial nerve nuclei discover study unit

12 cranial nerves list

To get familiar with this nerves, let’s list all castle in one place. 

Cranial nerves list
Cranial nerve 1Olfactory nerve (CN I) - sensory
Cranial nerve 2Optic nerve (CN II) - sensory
Cranial nerve 3Oculomotor nerve (CN III) - motor
Cranial nerve 4Trochlear nerve (CN IV) - motor
Cranial nerve 5Trigeminal nerve (CN V) - mixed
Cranial nerve 6Abducens nerve (CN VI) - motor
Cranial nerve 7Facial nerve (CN VII) - mixed
Cranial nerve 8Vestibulocochlear nerve (CN VIII) - sensory
Cranial nerve 9Glossopharyngeal nerve (CN IX) - mixed
Cranial nerve 10Vagus nerve (CN X) - mixed
Cranial nerve 11(Spinal) Accessory nerve (CN XI) - motor
Cranial nerve 12Hypoglossal nerve (CN XII) - motor

Test your knowledge about the cranial nerves by acquisition this quiz i m sorry is especially designed come cover the most crucial anatomy facts about the 12 cranial nerves!


Mnemonics

If we take the first letter of every nerve, we can build a mnemonic to help remember the cranial nerve names! 

Oh, Oh, Oh, To Touch And Feel Very Good Velvet, Such A Heaven

Olfactory nerve (CN I)Optic nerve (CN II)Occulomotor nerve (CN III)Trochlear nerve (CN IV)Trigeminal nerve (CN V)Abducens nerve (CN VI)Facial nerve (CN VII)Vestibulocochlear nerve (CN VIII)Glossopharyngeal nerve (CN IX)Vagus nerve (CN X)Accessory nerve (CN XI)Hypoglossal nerve (CN XII)

Or, if she a member the the take care of Potter fandom, you have the right to learn this one: On, On, On, They Traveled And Found Voldemort Guarding Very Ancient Horcruxes. Psychic these, and you’ll always be able come recall the cranial nerves in their numerical order. 


In addition, to remember if a nerve is sensory, engine or both in number order, mental this:

"Some say money matters, but my brothers says large brains issue most" 

Sensory (CN I)Sensory (CN II)Motor (CN III)Motor (CN IV)Both (CN V)Motor (CN VI)Both (CN VII)Sensory (CN VIII)Both (CN IX)Both (CN X)Motor (CN XI)Motor (CN XII)

Now that we’ve learned the tip on how to psychic cranial nerves and also their modalities, let’s get introduced to the anatomy the each one of them. 

Olfactory nerve (CN I)

Cranial nerve 1 is a unique somatic afferent nerve which innervates the olfactory mucosa within the sleep cavity. The carries information around smell to the brain.

Key facts about the olfactory nerve (CN I)
TypeSVA/SSA*
NucleusNone
Field that innervationSensory: sleep mucosa

The many branches the the olfactory nerve, referred to as fila olfactoria, happen from the nasal cavity v the cribriform bowl of the ethmoid bone. They terminate in the olfactory bulb, which proceeds as the olfactory tract. In ~ the brain, the fibers of the olfactory tract disperse and end in ~ the olfactory cortex (piriform cortex, amygdala, entorhinal cortex). 

The olfactory nerve doesn’t have actually a specific nucleus that its own. Instead its cabinet bodies are discovered in the olfactory area-the sleep mucosa that covers the roof that the sleep cavity. 

*Note that there is an recurring discussion about the modality that the olfactory nerve. Part authors speak it’s SSA, whilst the rather classify it together SVA. In any kind of case, friend won"t make a failure if you just say that it is a special afferent nerve.

Find out an ext about the olfactory nerve in the examine unit below, or take the quiz to see what you"ve learned therefore far!


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Olfactory nerve explore study unit
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tradition quiz: Olfactory nerve start quiz

Optic nerve (CN II)

Cranial nerve 2 is a distinct somatic afferent nerve i beg your pardon innervates the retina the the eye and also brings visual details to the brain. 

Key facts around the optic nerve (CN II)
TypeSSA
NucleusNone
Field of innervationSensory: Retina

Neural fibers originate from the photoreceptors the the retina. Lock converge in ~ the optic disc, forming the optic nerve. The optic nerve pipeline the orbit v the optic canal.

On the floor the the middle cranial fossa, the nasal components of every nerve cross to the contrary side creating the optic chiasm. The nerve fibers then continue as the 2 optic pathways. CN II likewise doesn’t have its very own nuclei, but instead its cabinet bodies are discovered in the retina. The optic nerve synapses with the visual relay centers of the brain. 

Eager to learn everything about the optic nerve? check out this study unit and also quiz we have actually prepared because that you.


Oculomotor nerve (CN III)

Cranial nerve 3 is both a somatic and also visceral efferent motor nerve. This way it has two nuclei and also carries two types of efferent fibers. As the name suggests, the oculomotor nerve is the chief motor nerve offering the eye.

It originates native the midbrain and leaves the skull with the exceptional orbital fissure to enter the orbit where it permits eye movement, constriction the the pupil (miosis) and lens accommodation.

Key facts about the oculomotor nerve (CN III)
TypeGSE, GVE (parasympathetic)
NucleiNucleus of oculomotor nerve (GSE)Accessory nuclei that oculomotor nerve (Edinger-Westphal) (GVE)
Field the innervationMotor: all extraocular muscles other than for the lateral rectus and also superior slope (GSE); ciliary muscle, sphincter pupillae muscle (GVE)

Solidify your knowledge around the oculomotor nerve with this research unit:


Trigeminal nerve (CN V)

Cranial nerve 5 is a combined nerve, include both distinct visceral and general somatic fibers. The fibers originate indigenous the brainstem, creating the trigeminal ganglion near the apex the the petrous part of the temporal bone.

The trigeminal nerve divides into three divisions; ophthalmic nerve (CN V1), maxillary nerve (CN V2) and also mandibular nerve (CN V3). Each of them leaves the skull through a various opening. Ophthalmic leaves through the superior orbital fissure, maxillary through the foramen rotundum and the mandibular nerve exit via the foramen ovale.

Key facts about the trigeminal nerve (CN V)
TypeSVE, GSA
NucleiMotor cell nucleus of trigeminal nerve (SVE)Principal sensory cell core of trigeminal nerve (GSA)Spinal nucleus of trigeminal nerve (GSA)Mesencephalic cell nucleus of trigeminal nerve (GSA)
DivisionsOphthalmic nerve (CN V1)Maxillary nerve (CN V2)Mandibular nerve (CN V3)
Field that innervationMotor: muscle of mastication, mylohyoid, anterior belly of digastric, tensor tympani muscles (SVE)Sensory: Scalp, face, orbit, paranasal sinuses, anterior two-thirds the the tongue (GSA) 

All three branches that the trigeminal nerve supply sensation to the facial skin. The areas of cutaneous innervation (dermatomes) room as follows; Ophthalmic nerve (CN V1 dermatome) gives the forehead, orbit and nose, maxillary nerve (CN V2 dermatome) the zygomatic region and top lip, if the mandibular nerve (CN V3 dermatome) innervates the buccal skin, reduced lip and also skin of the mandibular region.

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Abducens nerve (CN VI)

Cranial nerve 6 is a basic somatic efferent nerve which innervates the lateral rectus muscle (extraocular). The abducens nerve originates from the brainstem and also exits the skull via the remarkable orbital fissure.

Key facts around the abducens nerve (CN VI)
TypeGSE
NucleusNucleus that abducens nerve
Field that innervationMotor: Lateral rectus muscle

Although it might seem the the very least relevant, the abducens nerve dram a very important function in eye movement. Just ask anyone through strabismus.

Learn all around this nerve in the research unit below and then check what you"ve learned for this reason far around the oculomotor, trochlear and also abducens nerve v our qustom quiz below!


Facial nerve (CN VII)

Cranial nerve 7 is a multimodal nerve, delivering both general and special fibers. It originates indigenous the brainstem as two separate divisions; a larger primary root transferring motor fibers and also a smaller sized intermediate nerve delivering sensory and parasympathetic fibers.

The two departments leave the cranial cavity v the internal acoustic meatus and also then travel v the face canal. Below they join developing the face nerve proper and also leave the cranium together with the stylomastoid foramen. When the facial nerve reaches the face it allows many functions, such as facial expression, cheap of glands and also taste sensation.

Key facts around the facial nerve (CN VII)
TypeGVE (parasympathetic), SVE, GVA, SVA, GSA
NucleiSuperior salivatory cell core (GVE)Motor cell core of face nerve (SVE)Nuclei the solitary street (GVA, SVA)Spinal cell core of trigeminal nerve (GSA)
Field that innervationSensory: middle ear, sleep cavity, soft palate (GVA); anterior two-thirds of the tongue (SVA); exterior auditory meatus (GSA)Motor: lacrimal, submandibular, sublingual, basal, palatine glands (GVE); muscle of face expression (SVE)

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Vestibulocochlear nerve (CN VIII)

Cranial nerve 8 is a unique somatic afferent nerve. That is comprised of 2 parts: the vestibular nerve and the cochlear nerve. The cochlear component allows hearing, while the vestibular part mediates balance and motion. In ~ the fundus of internal acoustic meatus, both components unite to kind the vestibulocochlear nerve and enter the cranium with the internal acoustic meatus.

Key facts about the vestibulocochlear nerve (CN VIII)
TypeSSA
NucleiVestibular nucleiDorsal and ventral cochlear nuclei 
Field that innervationSensory: Spiral organ (of Corti), macula of utricle, macula that saccule, ampullae the the semicircular canals (SSA)

The 2 components synapse with their particular nuclei in the brainstem. To conserve you native confusion, keep in mind that dorsal and ventral cochlear nuclei hatchet varies. Periodically you’ll watch them together anterior and posterior cochlear nuclei, and elsewhere just grouped together the auditory nuclei. 

Master the vestibulocochlear nerve anatomy with our user resources:


Glossopharyngeal nerve (CN IX)

Cranial nerve 9 is an additional multimodal nerve. It originates native the brainstem and also leaves the skull with the jugular foramen. It permits swallowing, salivation, and taste sensation, as well as visceral and general sensation in the dental cavity.

Key facts about the glossopharyngeal nerve (CN IX)
TypeSVE, GVE (parasympathetic), SVA, GVA, GSA
NucleiNucleus ambiguus (SVE, GVA)Inferior salivatory cell nucleus (GVE)Nuclei of solitary street (SVA, GVA)Spinal cell nucleus of trigeminal nerve (GSA)
Field of innervationMotor: stylopharyngeus and also pharyngeal constrictors (SVE); parotid gland (GVE)Sensory: posterior one-third the the tongue (SVA); center ear, pharynx, epiglottis, carotid body, carotid sinus (GVA); posterior one-third that the tongue, soft palate (GSA)

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Vagus nerve (CN X)

Cranial nerve 10 is additionally a multimodal nerve, it originates indigenous multiple nuclei in the brainstem, and also exits the skull with the jugular foramen. It is the longest cranial nerve and the only one to leaving the head and neck region. The vagus nerve travels right into the thoracic and ab cavities, offering parasympathetic supply to visceral organs. 

Key facts about the vagus nerve (CN X)
TypeGVE (parasympathetic), SVE, SVA, GVA, GSA
NucleiPosterior nucleus of vagus nerve (dorsal motor nucleus) (GVE)Nucleus ambiguus (SVE)Nuclei of solitary tract (SVA, GVA)Spinal cell nucleus of trigeminal nerve (GSA)
Field of innervationMotor: thoracic and abdominal viscera (GVE); laryngeal and also pharyngeal muscles (SVE)Sensory: epiglottis (SVA); thoracic and ab viscera, carotid body (GVA); exterior acoustic meatus, retroauricular skin, posterior part of meninges (GSA)

CN 10 has actually two ganglia, called the premium ganglion the the vagus nerve and also the worse ganglion that the vagus nerve (nodose ganglion). The former provides fibers for basic sensory function, when the latter gives special sensory and visceral output.

The vagus nerve controls a big number the functions, including gland secretion, peristalsis, phonation, taste, visceral and also general emotion of the head, thorax and abdomen. This cranial nerve is frequently tested in anatomy exams.

Use our contents to swot increase on the vagus nerve and also ace her cranial nerve exams!


Accessory nerve (CN XI)

Cranial nerve 11 is an efferent nerve originating from the brainstem and spinal cord. It exit the skull with the jugular foramen, acting to enable phonation and movements that the head and shoulders.

Sensory yarn of the cervical plexus sign up with the accessory nerve enabling general sensation because that its target muscles. So when you feeling comfortable while obtaining a shoulder massage, give thanks to your cervical plexus because that that.

Key facts around the accessory nerve (CN XI)
TypeGSE/SVE*
NucleiAmbiguusNucleus that the accessory nerve (C1-C5)
Field the innervationMotor: Laryngeal muscles, sternocleidomastoid, trapezius

The (spinal) accessory nerve is exciting in that anatomists still don’t agree on exactly where that is nerve fibers originate from. *Some dispute that the is a SVE nerve, believing the spinal accessory nucleus come be consistent with the cell core ambiguus (which is SVE). Yet others describe it together a GSE nerve, providing motor innervation come the three muscles there is no nucleus ambiguus involvement. There are likewise anatomists who believe that the CN XI contains both SVE and GSE nerves, receiving fibers from both nuclei sources.

Learn everything around the accessory nerve through our rwcchristchurchappeal.com examine materials.


Hypoglossal nerve (CN XII)

Cranial nerve 12 is a basic somatic efferent nerve originating from the brainstem. It pipeline the skull v the hypoglossal foramen. It’s function is to allow tongue movements.

Key facts about the hypoglossal nerve (CN XII)
TypeGSE
NucleusNucleus the hypoglossal nerve
Field of innervationMotor: Intrinsic tongue muscles, extrinsic tongue muscle (except because that the palatoglossus)

The hypoglossal nerve is extremely necessary for smooth everyday functioning that every person, as it dram a far-reaching role in necessary mouth features such together speech and swallowing. Similar to CN XI, the hypoglossal nerve additionally interacts v the cervical plexus. The receives GSE yarn from C1 and C2 spinal nerves, and GSA yarn from the spinal ganglion that C2 spinal nerve.

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Master the hypoglossal nerve anatomy v our study material:


Sources

References:

Blumenfeld, H. (2018). Neuroanatomy with clinical situations (2nd ed.). Sunderland, MA: Sinauer.Haines, D. E. (2012). Neuroanatomy: one atlas that structures, sections, and systems (8th ed.). Philadelphia, PA: Wolters Kluwer/ Lippincott Williams & Wilkins Health.Jacobson, S., & Marcus, E. M. (2008). Neuroanatomy because that the neuroscientist. New York: Springer.Kahle, W., Frotscher, M., & Spitzer, G. (2003). Concerned system and also sensory organs. Brand-new York: Thieme.Waxman, S. G. (2010). Clinical neuroanatomy (26th ed.). New York: McGraw-Hill Medical.

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