what are the 3 cranial nerves

by D'angelo Altenwerth Published 3 years ago Updated 2 years ago

List of the Cranial Nerves

I Olfactory (Smell)
II Optic (Sight)
III Oculomotor (Moves eyelid and eyeball and adjusts the pupil and lens of the eye)
IV Trochlear (Moves eyeballs)
V Trigeminal (Facial muscles incl. ...
VI Abducens (Moves eyeballs)
VII Facial (Taste, tears, saliva, facial expressions)
VIII Vestibulocochlear (Auditory)
IX Glossopharyngeal (Swallowing, saliva, taste)

Olfactory nerve (CN I) enables sense of smell. Optic nerve (CN II) enables vision. Trigeminal nerve (CN V) enables sensation in your face.Aug 10, 2021

Full Answer

What is the function of the third cranial nerve?

The oculomotor nerve (the third cranial nerve; CN III) has three main motor functions:

Innervation to the pupil and lens (autonomic, parasympathetic)
Innervation to the upper eyelid (somatic)
Innervation of the eye muscles that allow for visual tracking and gaze fixation (somatic)

What is the third cranial nerve referred to as?

The third cranial nerve is also known as oculomotor nerve and has 2 major components: Outer parasympathetic fibers that supply the ciliary muscles and the sphincter pupillae

What is the easiest way to learn cranial nerves?

To learn them the best I suggest you:

Watch my teaching video (below) on how to remember them
Take the Quiz on Cranial Nerves
Memorize the illustration of the cranial nerves below
Print off this article for reference

What are three cranial nerves have only sensory function?

This article will provide an introduction to the cranial nerves which are considered primarily sensory nerves, which includes the olfactory nerve, the optic nerve, and the vestibulocochlear nerve. The terminal nerve (CN 0, or CN N), although not conventionally included in the list of cranial nerves, will also be discussed among this group.

What are the 3 main cranial nerves?

Abducens nerve: Ability to move your eyes. Facial nerve: Facial expressions and sense of taste. Auditory/vestibular nerve: Sense of hearing and balance.

What are the cranial nerves and their function?

The functions of the cranial nerves are sensory, motor, or both. Sensory cranial nerves help a person see, smell, and hear. Conversely, motor cranial nerves help control muscle movements in the head and neck. Each nerve has a name that reflects its function and a number according to its location in the brain.

Which 3 cranial nerves are tested together?

CN IX and CN X nerves can be assessed together:Ask the patient to cough (assessing CN X)Ask the patient to open the mouth wide and say 'ah', using a tongue depressor to visual the palate and posterior pharyngeal wall (assessing CN IX and X) The soft palate should move upwards centrally.

What are the cranial nerves in order?

Cranial nerve functionI. Olfactory nerve. The olfactory nerve sends sensory information to your brain about smells that you encounter. ... II. Optic nerve. ... III. Oculomotor nerve. ... IV. Trochlear nerve. ... V. Trigeminal nerve. ... VI. Abducens nerve. ... VII. Facial nerve. ... VIII. Vestibulocochlear nerve.More items...

What is the largest cranial nerve?

The vagus nerve (cranial nerve [CN] X) is the longest cranial nerve in the body, containing both motor and sensory functions in both the afferent and efferent regards.

How can I remember the cranial nerves?

0:001:40Cranial Nerves Mnemonic Easy to Remember - YouTubeYouTubeStart of suggested clipEnd of suggested clipCranial nerves can be hard to remember that's why in this first installment of pneumonic Monday we'MoreCranial nerves can be hard to remember that's why in this first installment of pneumonic Monday we'll be checking out a mnemonic on how to remember the 12 cranial nerves. And you'll never forget them

What does the 3rd cranial nerve control?

The oculomotor nerve (the third cranial nerve; CN III) has three main motor functions: Innervation to the pupil and lens (autonomic, parasympathetic) Innervation to the upper eyelid (somatic) Innervation of the eye muscles that allow for visual tracking and gaze fixation (somatic)

What is the function of the vagus nerve?

The vagus nerve is responsible for the regulation of internal organ functions, such as digestion, heart rate, and respiratory rate, as well as vasomotor activity, and certain reflex actions, such as coughing, sneezing, swallowing, and vomiting (17).

What happens when cranial nerve 3 is damaged?

The oculomotor (third) cranial nerve plays an important role in the efferent visual system by controlling ipsilateral eye movements, pupil constriction, and upper eyelid elevation. Accordingly, damage to the third cranial nerve may cause diplopia, pupil mydriasis, and/or upper eyelid ptosis.

What are the 12 cranial nerves names?

In higher vertebrates (reptiles, birds, mammals) there are 12 pairs of cranial nerves: olfactory (CN I), optic (CN II), oculomotor (CN III), trochlear (CN IV), trigeminal (CN V), abducent (or abducens; CN VI), facial (CN VII), vestibulocochlear (CN VIII), glossopharyngeal (CN IX), vagus (CN X), accessory (CN XI), and ...

Where are the 12 cranial nerves located?

The cranial nerves consist of 12 paired nerves that arise from the brainstem. The olfactory and optic nerves arise from the anterior portion of the brain called the cerebrum. The oculomotor and trochlear cranial nerves stem from the midbrain. The trigeminal, abducens, and facial nerves arise in the pons.

What are the 4 types of nerves?

It is conventional, however, to describe nerve types on the basis of their function: motor, sensory, autonomic or cranial.Motor Nerves. ... Sensory Nerves. ... Autonomic Nerves. ... Cranial Nerves.

What are the 12 cranial nerves names?

What are the 12 pairs of cranial nerves and their functions quizlet?

Terms in this set (12)I Olfactory. Smell.II - Optic. Vision.III - Oculomotor. Eyelid & eyeball movement.IV - Trochlear. Innervates superior oblique turns eye downward & laterally.V - Trigeminal. Chewing. ... VI - Abducens. Turns eye laterally.VII - Facial. Controls most facial expression. ... VIII - Vestibulocochlear (Auditory)More items...

Where are the 12 cranial nerves located?

What are cranial nerves definition?

Listen to pronunciation. (KRAY-nee-ul nerv) One of twelve pairs of nerves that pass from the brain, through openings in the skull, to different areas of the head, neck, chest, and abdomen. The cranial nerves send information between the brain and the sense organs (the eyes, ears, nose, and tongue).

How many cranial nerves are there in the human body?

There are 12 pairs of cranial nerves in the human body. The olfactory nerve, optic nerve, facial nerve, oculomotor nerve, vagus nerve, hypoglossal,...

What is the purpose of cranial nerves in the human body?

The cranial nerves carry information from the brain to all parts of the body and facilitate the sense of vision, smell, muscle movement and hearing.

How are cranial nerves different from spinal nerves?

The cranial nerves emerge directly from the brain and brain stem. On the contrary, the spinal nerves emerge from the segments in the spinal cord. T...

What is a spinal nerve?

A spinal nerve is a mixed nerve that transmits sensory, motor or autonomic signals between the spinal cord to the body. There are 31 pairs of spina...

What is the function of the optic nerve?

The optic nerve relays signals between the brain and the eyes and acts as the agent of vision.

What happens if the vestibulocochlear nerve gets damaged?

If the vestibulocochlear nerve gets damaged it results in dizziness and spinning.

What is an accessory nerve?

The accessory nerve is the cranial nerve that arises from the cranial and the spinal bones and is responsible for controlling the swallowing and th...

What are the cranial nerves?

What are Cranial Nerves? “Nerves that extend throughout the body on both sides emerging directly from brain and brain stem are called cranial nerves.”. Cranial nerves carry information from the brain to other parts of the body, primarily to the head and neck. These nerves are paired and present on both sides of the body.

Which system is the cranial nerve in?

Most of the cranial nerves belong to the somatic system. Some of the cranial nerves are responsible for sensory and motor functions as they contain only sensory fibres ...

What nerve is responsible for hearing and balance?

Vestibulocochlear nerve (auditory vestibular nerve): Vestibulocochlear (auditory vestibular nerve) is responsible for hearing and balance. This helps eyes to keep track of moving objects while your head is stable. The sensation of spinning and dizziness are the symptoms of damage to this nerve.

What nerves help with double vision?

Damage to this nerve leads to distortion in vision or double vision and even problem in the coordination of eyes. Trochlear and Abducens nerves: These nerves also help in eye movement. Damage to the Trochlear nerve might cause inability to move eyeball downwards and damage to abducens nerve might result in diplopia.

What are the functions of cranial nerves?

Functions of Cranial Nerves. Following is the cranial nerves list along with the important functions they perform: Olfactory nerve: This nerve helps to feel the sense of smell. This is the primary nerve that is responsible for the smell. Damage to this nerve may result in distortion of smell and taste.

Why are cranial nerves mixed?

Others are mixed nerves because they include both sensory and motor fibres. Only cranial nerves I and II are purely sensory and are responsible for the sense of smell and vision (optic nerve II). The rest of the cranial nerves contain both afferent and efferent fibres and are therefore referred to as the mixed cranial nerves.

How many pairs of spinal nerves are there in the human body?

A spinal nerve is a mixed nerve that transmits sensory, motor or autonomic signals between the spinal cord to the body. There are 31 pairs of spinal nerves in the human body.

How many cranial nerves are there?

What are cranial nerves? Your cranial nerves are pairs of nerves that connect your brain to different parts of your head, neck, and trunk. There are 12 of them, each named for their function or structure. Each nerve also has a corresponding Roman numeral between I and XII.

What are the functions of the cranial nerves?

Their functions are usually categorized as being either sensory or motor. Sensory nerves are involved with your senses, such as smell, hearing, and touch. Motor nerves control the movement and function of muscles or glands. Keep reading to learn more about each of the 12 cranial nerves and how they function.

What is the function of the oculomotor nerve?

The oculomotor nerve has two different motor functions: muscle function and pupil response. Muscle function. Your oculomotor nerve provides motor function to four of the six muscles around your eyes. These muscles help your eyes move and focus on objects.

How many divisions does the trigeminal nerve have?

The trigeminal nerve has three divisions, which are:

Which nerve is located in the ophthalmic, maxillary, and mandibular divisions?

The sensory root of your trigeminal nerve branches into the ophthalmic, maxillary, and mandibular divisions. The motor root of your trigeminal nerve passes below the sensory root and is only distributed into the mandibular division. VI. Abducens nerve.

Which nerve transmits sensory information to your brain regarding smells that you encounter?

The olfactory nerve transmits sensory information to your brain regarding smells that you encounter.

Where does the trigeminal nerve originate?

It also controls the movement of muscles within your jaw and ear. The trigeminal nerve originates from a group of nuclei — which is a collection of nerve cells — in the midbrain and medulla regions of your brainstem.

Which nerve enervates the muscles of the face?

The abducent nerve enervates a muscle, which moves the eyeball. The facial nerve enervates the muscles of the face (facial expression). The vestibulocochlear nerve is responsible for the sense of hearing and balance (body position sense). The glossopharyngeal nerve enervates muscles involved in swallowing and taste.

Which nerve controls the facial muscles?

The trochlear nerve controls an extraocular muscle. The trigeminal nerve is responsible for sensory enervation of the face and motor enervation to muscles of mastication (chewing). The abducent nerve enervates a muscle, which moves the eyeball. The facial nerve enervates the muscles of the face (facial expression).

Which nerve enervates the sternocleidomastoid muscles and the trapezius muscles?

The vagus nerve enervates the gut ( gastrointestinal tract ), heart and larynx. The accessory nerve enervates the sternocleidomastoid muscles and the trapezius muscles. The hypoglossal nerve enervates the muscles of the tongue.

Which nerve controls the sense of smell?

The olfactory nerve carries impulses for the sense of smell. The optic nerve carries impulses for the sense of sight. The occulomotor nerve is responsible for motor enervation of upper eyelid muscle, extraocular muscle and pupillary muscle. The trochlear nerve controls an extraocular muscle.

What is the name of the nerve that carries impulses for the sense of smell?

The following are the list of cranial nerves, their functions, and tumor examples: The olfactory nerve carries impulses for the sense of smell.

How many cranial nerves are there?

Test your knowledge about the cranial nerves by taking this quiz which is specially designed to cover the most important anatomy facts about the 12 cranial nerves!

Where do cranial nerves originate?

All cranial nerves originate from nuclei in the brain. Two originate from the forebrain (Olfactory and Optic), one has a nucleus in the spinal cord (Accessory) while the remainder originate from the brainstem. There's a LOT to learn about the cranial nerves.

What nerve controls the head?

The vagus nerve controls a large number of functions, including gland secretion, peristalsis, phonation, taste, visceral and general sensation of the head, thorax and abdomen. This cranial nerve is frequently tested in anatomy exams. Use our content to swot up on the vagus nerve and ace your cranial nerve exams!

Why is cranial nerve anatomy important?

Cranial nerves anatomy is essential for almost any medical specialty since they control so many body functions, such as rolling your eyes when you’re annoyed by something. So let’s break the stigma of them being hard to understand, and learn this important neuroanatomy topic once and for all.

What is the function of a nerve?

The function of a nerve is to carry sensory and/or motor information between the body and the brain. If the information goes from the brain to the periphery, then it is an efferent (motor) nerve. If it travels from the periphery to the brain, then it is an afferent (sensory) nerve. Nerves that do both are mixed nerves.

What is the CN IV?

Trochlear nerve (CN IV) Cranial nerve 4 is a general somatic motor nerve. The trochlear nerve originates from the midbrain and enters the orbit through the superior orbital fissure, supplying one extraocular muscle thus playing a role in eye movement. Key facts about the trochlear nerve (CN IV) Type. GSE.

Which nerve innervates the olfactory mucosa?

Cranial nerve 1 is a special somatic afferent nerve which innervates the olfactory mucosa within the nasal cavity. It carries information about smell to the brain.

What are the names of the cranial nerves?

Cranial nerves are generally named according to their structure or function. For example, the olfactory nerve (I) supplies smell, and the facial nerve (VII) supplies the muscles of the face. Because Latin was the lingua franca of the study of anatomy when the nerves were first documented, recorded, and discussed, many nerves maintain Latin or Greek names, including the trochlear nerve (IV), named according to its structure, as it supplies a muscle that attaches to a pulley ( Greek: trochlea ). The trigeminal nerve (V) is named in accordance with its three components ( Latin: trigeminus meaning triplets ), and the vagus nerve (X) is named for its wandering course ( Latin: vagus ).

How many cranial nerves are there in the human body?

Most typically, humans are considered to have twelve pair s of cranial nerves (I–XII), with the terminal nerve (0) more recently canonized. The nerves are: the olfactory nerve (I), the optic nerve (II), oculomotor nerve (III), trochlear nerve (IV), trigeminal nerve (V), abducens nerve (VI), facial nerve (VII), vestibulocochlear nerve (VIII), glossopharyngeal nerve (IX), vagus nerve (X), accessory nerve (XI), and the hypoglossal nerve (XII).

Why do nerves get compressed?

Nerves may be compressed because of increased intracranial pressure, a mass effect of an intracerebral haemorrhage, or tumour that presses against the nerves and interferes with the transmission of impulses along the nerve. Loss of function of a cranial nerve may sometimes be the first symptom of an intracranial or skull base cancer.

What nerves are responsible for the sense of smell and vision?

Cranial nerves relay information between the brain and parts of the body, primarily to and from regions of the head and neck, including the special senses of vision, taste, smell, and hearing. The cranial nerves emerge from the central nervous system above the level of the first vertebrae of the vertebral column.

What are the sensory nerves?

The ganglion of the sensory nerves, which are similar in structure to the dorsal root ganglion of the spinal cord, include: 1 The trigeminal ganglia of the trigeminal nerve (V), which occupies a space in the dura mater called Meckel's cave. This ganglion contains only the sensory fibres of the trigeminal nerve. 2 The geniculate ganglion of the facial nerve (VII), which occurs just after the nerve enters the facial canal. 3 A superior and inferior ganglia of the glossopharyngeal nerve (IX), which occurs just after it passes through the jugular foramen.

Why are nerves named IV?

Because Latin was the lingua franca of the study of anatomy when the nerves were first documented, recorded, and discussed, many nerves maintain Latin or Greek names, including the troch lear nerve (IV), named according to its structure, as it supplies a muscle that attaches to a pulley ( Greek: trochlea ).

How to check cranial nerves?

Vision may be tested by examining the visual fields, or by examining the retina with an ophthalmoscope, using a process known as funduscopy. Visual field testing may be used to pin-point structural lesions in the optic nerve, or further along the visual pathways. Eye movement is tested and abnormalities such as nystagmus are observed for. The sensation of the face is tested, and patients are asked to perform different facial movements, such as puffing out of the cheeks. Hearing is checked by voice and tuning forks. The patient's uvula is examined. After performing a shrug and head turn, the patient's tongue function is assessed by various tongue movements.

How many cranial nerves are there?

The twelve cranial nerves are a group of nerves that start in the brain and provide motor and sensory functions to the head and neck. Each cranial nerve has its unique anatomical characteristics and functions. Doctors can identify neurological or psychiatric disorders by testing cranial nerve functions. Last medically reviewed on October 10, 2019.

What are the functions of the cranial nerves?

Each has a different function for sense or movement. The functions of the cranial nerves are sensory, motor, or both: Sensory cranial nerves help a person to see, smell, and hear. Motor cranial nerves help control muscle movements in the head and neck.

What nerve helps the body sense changes in the position of the head with regard to gravity?

The vestibular nerve helps the body sense changes in the position of the head with regard to gravity. The body uses this information to maintain balance.

Which nerve provides movement to most of the muscles that move the eyeball and upper eyelid, known as extraocular?

The oculomotor nerve provides movement to most of the muscles that move the eyeball and upper eyelid, known as extraocular muscles.

Which nerve is involved in eye movement?

The trochlear nerve is also involved in eye movement.

Which nerves help control muscle movements in the head and neck?

Motor cranial nerves help control muscle movements in the head and neck.

How many nuclei are in the facial nerve?

The facial nerve is made up of four nuclei that serve different functions:

Which cranial nerve is responsible for eye movements?

The oculomotor nerve is the third cranial nerve (CN III). It enables eye movements, such as focusing on an object that’s in motion. Cranial nerve III also makes it possible to move your eyes up, down and side to side.

What nerve enables sensation in your face?

Trigeminal nerve (CN V) enables sensation in your face.

What nerve controls the movement of the eye?

The oculomotor nerve is the third cranial nerve. It controls four of the six muscles that enable eye movement. Conditions affecting cranial nerve III include third nerve palsy. It is often a complication of medical issues such as uncontrolled diabetes or a brain aneurysm. Third nerve palsy might impact your vision and the appearance of one or both of your eyes. Many people make a full recovery, although it can take around two months.

What is the oculomotor nerve?

The oculomotor nerve is one of 12 sets of cranial nerves. Many of these nerves are part of the autonomic nervous system. The autonomic nervous system supplies (innervates) organs, like your eyes.

How long does it take to see double vision after third nerve palsy?

An ophthalmologist will wait at least 6 months after onset of third nerve palsy to see if it gets better on its own. During this time, an eye patch or prism glasses may help you with double vision. Eye muscle surgery (strabismus surgery) may help to realign the eyes so that the eyes are straight when looking straight ahead. But it can sometimes take numerous procedures. People typically still experience double vision when looking to the sides after strabismus surgery.

When does third nerve palsy occur?

Third nerve palsy can be present at birth. It may also occur later in life due to:

Can CN III be prevented?

It might not be possible to prevent certain conditions that affect CN III. For example, complications from neurological disease or tumors may be unavoidable.

What is the ocular deviation of third nerve palsy?

Ocular deviation: In case of third-nerve palsy, the lateral rectus and superior oblique are spared, and their unopposed action brings the eye in a “down and out” position.

How long does it take to treat third nerve palsy?

In pupil-sparing cases, surgical treatment is advised after 6 months in acquired palsies, if there is no improvement in symptoms. Surgery for third-nerve palsy is nevertheless challenging, and the goals are to provide alignment of the eye in primary gaze and to provide binocular single vision. Before operating on the lid to correct ptosis, the eye should be aligned to prevent diplopia. Surgical options for TNP depend on the degree of the palsy: complete or partial. Surgery for complete third-nerve palsy includes resection of the medial rectus and recession of the lateral rectus muscle for correction of horizontal deviation.[13] This may be combined with superior oblique (SO) tendon transposition, which causes a tonic adducting force to the globe to keep it in the primary position.[2] In patients with partial third-nerve palsy, surgery depends on the extent of involvement of extraocular muscles[2]. After the paralytic strabismus is treated, the ptosis can be corrected. Pupil involving third-nerve palsy should be investigated thoroughly and referred to a neurologist. [14]

How long does it take for a third nerve palsy patient to recover?

Most patients with ischemic third-nerve palsy demonstrate improvement within 1 month and complete recovery in 3 months. In cases of diplopia, the affected eye can be occluded with the help of an eye patch or opaque contact lens.[2] In pediatric cases, amblyopia due to ptosis or squint can be prevented by alternate patching. Talebnejad et al. documented botulinum toxin injection in lateral rectus (LR) in the acute phase of partial third-nerve palsy.[12] Botulinum toxin causes paralysis of the LR, and subsequently, the outward deviation of the eye is neutralized in the primary position.

Where do the oculomotor nerves pass?

As shown in the figure below, fibers pass through the interpeduncular fossa before passing between the posterior cerebral artery and the superior cerebellar artery to reach the cavernous sinus. During this course, the oculomotor nerve lies lateral to the posterior communicating artery. The nerve then divides into a superior and inferior division and enters the orbit through the superior orbital fissure.[8] In the orbit, the smaller superior division supplies the superior rectus and the levator palpebrae superioris, whereas the larger inferior division supplies the medial rectus, the inferior rectus, and the inferior oblique. An interesting point to note is that before the 3 nerve reaches the orbit, the fibers innervating the pupillary muscles (pupillomotor fibers) are located superficially in the nerve trunk. The pial blood vessels supply these fibers. In contrast, the main trunk of the fibers is supplied by the vasa vasorum.

What is the Creative Commons 4.0 license?

This book is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, duplication, adaptation, distribution, and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, a link is provided to the Creative Commons license, and any changes made are indicated.

What causes nerve palsy?

Diabetes mellitus and hypertension cause ischemic changes in the nerve and are the most common systemic causes of acquired nerve palsy. [1]

Which lesions cause conjugate paresis?

Supranuclear lesions: Lesions at the level of the cerebral cortex or the supranuclear pathway cause conjugate paresis of both the eyes.