The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the

pons The pons (from Latin , "bridge") is part of the brainstem that in humans and other bipeds lies inferior to the midbrain, superior to the medulla oblongata and anterior to the cerebellum. The pons is also called the pons Varolii ("bridge of Va ...

of the brainstem, controls the

muscles of facial expression The facial muscles are a group of striated skeletal muscles supplied by the facial nerve (cranial nerve VII) that, among other things, control facial expression. These muscles are also called mimetic muscles. They are only found in mammals, al ...

, and functions in the conveyance of

taste The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception produced or stimulated when a substance in the mouth reacts chemically with taste receptor ...

sensations from the anterior two-thirds of the

tongue The tongue is a muscular organ (anatomy), organ in the mouth of a typical tetrapod. It manipulates food for mastication and swallowing as part of the digestive system, digestive process, and is the primary organ of taste. The tongue's upper surfa ...

. The nerve typically travels from the pons through the

facial canal The facial canal (''canalis nervi facialis''), also known as the Fallopian canal, is a Z-shaped canal running through the temporal bone of the skull. It runs from the internal acoustic meatus to the stylomastoid foramen. It contains the facial ...

in the

temporal bone The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples, and house the structures of the ears. Th ...

and exits the skull at the stylomastoid foramen. It arises from the brainstem from an area posterior to the cranial nerve VI (abducens nerve) and anterior to

cranial nerve VIII The vestibulocochlear nerve or auditory vestibular nerve, also known as the eighth cranial nerve, cranial nerve VIII, or simply CN VIII, is a cranial nerve that transmits sound and equilibrium (balance) information from the inner ear to the b ...

(vestibulocochlear nerve). The facial nerve also supplies preganglionic parasympathetic fibers to several head and neck ganglia. The facial and

intermediate nerve The intermediate nerve, nervus intermedius, nerve of Wrisberg or Glossopalatine nerve, is the part of the facial nerve (cranial nerve VII) located between the motor component of the facial nerve and the vestibulocochlear nerve (cranial nerve VIII) ...

s can be collectively referred to as the nervus intermediofacialis.

Structure

The path of the facial nerve can be divided into six segments: # intracranial (cisternal) segment # meatal (canalicular) segment (within the internal auditory canal) # labyrinthine segment (internal auditory canal to geniculate ganglion) # tympanic segment (from

geniculate ganglion The geniculate ganglion (from Latin ''genu'', for "knee") is a collection of pseudounipolar sensory neurons of the facial nerve located in the facial canal of the head. It receives fibers from the facial nerve. It sends fibers that supply the la ...

to pyramidal eminence) # mastoid segment (from pyramidal eminence to stylomastoid foramen) # extratemporal segment (from stylomastoid foramen to post parotid branches) The motor part of the facial nerve arises from the facial nerve nucleus in the

, while the sensory and parasympathetic parts of the facial nerve arise from the

. From the brain stem, the motor and sensory parts of the facial nerve join together and traverse the

posterior cranial fossa The posterior cranial fossa is part of the cranial cavity, located between the foramen magnum and tentorium cerebelli. It contains the brainstem and cerebellum. This is the most inferior of the fossae. It houses the cerebellum, medulla and pons. ...

before entering the

petrous temporal bone The petrous part of the temporal bone is pyramid-shaped and is wedged in at the base of the skull between the sphenoid and occipital bones. Directed medially, forward, and a little upward, it presents a base, an apex, three surfaces, and three a ...

via the

internal auditory meatus The internal auditory meatus (also meatus acusticus internus, internal acoustic meatus, internal auditory canal, or internal acoustic canal) is a canal within the petrous part of the temporal bone of the skull between the posterior cranial fossa ...

. Upon exiting the internal auditory meatus, the nerve then runs a tortuous course through the

, which is divided into the labyrinthine, tympanic, and mastoid segments. The labyrinthine segment is very short, and ends where the facial nerve forms a bend known as the geniculum of the facial nerve (''genu'' meaning knee), which contains the

for sensory nerve bodies. The first branch of the facial nerve, the

greater petrosal nerve The greater petrosal nerve (or greater superficial petrosal nerve) is a nerve in the skull that branches from the facial nerve; it forms part of a chain of nerves that innervate the lacrimal gland. The preganglionic parasympathetic axons of this ne ...

, arises here from the geniculate ganglion. The greater petrosal nerve runs through the

pterygoid canal The pterygoid canal (also vidian canal) is a passage in the sphenoid bone of the skull leading from just anterior to the foramen lacerum in the middle cranial fossa to the pterygopalatine fossa. Structure The pterygoid canal runs through the me ...

and synapses at the

pterygopalatine ganglion The pterygopalatine ganglion (aka Meckel's ganglion, nasal ganglion, or sphenopalatine ganglion) is a parasympathetic ganglion found in the pterygopalatine fossa. It is largely innervated by the greater petrosal nerve (a branch of the facial n ...

. Postsynaptic fibers of the greater petrosal nerve innervate the

lacrimal gland The lacrimal glands are paired exocrine glands, one for each eye, found in most terrestrial vertebrates and some marine mammals, that secrete the aqueous layer of the tear film. In humans, they are situated in the upper lateral region of each or ...

. In the tympanic segment, the facial nerve runs through the

tympanic cavity The tympanic cavity is a small cavity surrounding the bones of the middle ear. Within it sit the ossicles, three small bones that transmit vibrations used in the detection of sound. Structure On its lateral surface, it abuts the external auditory ...

, medial to the

incus The ''incus'' (plural incudes) or anvil is a bone in the middle ear. The anvil-shaped small bone is one of three ossicles in the middle ear. The ''incus'' receives vibrations from the ''malleus'', to which it is connected laterally, and transmit ...

. The pyramidal eminence is the second bend in the facial nerve, where the nerve runs downward as the mastoid segment. In the temporal part of the facial canal, the nerve gives rise to the nerve to the

stapedius muscle The stapedius is the smallest skeletal muscle in the human body. At just over one millimeter in length, its purpose is to stabilize the smallest bone in the body, the stapes or strirrup bone of the middle ear. Structure The stapedius emerges from ...

and

chorda tympani The chorda tympani is a branch of the facial nerve that originates from the taste buds in the front of the tongue, runs through the middle ear, and carries taste messages to the brain. It joins the facial nerve (cranial nerve VII) inside the fa ...

. The chorda tympani supplies taste fibers to the anterior two thirds of the tongue, and also synapses with the

submandibular ganglion The submandibular ganglion (or submaxillary ganglion in older texts) is part of the human autonomic nervous system. It is one of four parasympathetic ganglia of the head and neck. (The others are the otic ganglion, pterygopalatine ganglion, and ci ...

. Postsynaptic fibers from the submandibular ganglion supply the sublingual and

submandibular glands The paired submandibular glands (historically known as submaxillary glands) are major salivary glands located beneath the floor of the mouth. They each weigh about 15 grams and contribute some 60–67% of unstimulated saliva secretion; on stimula ...

. Upon emerging from the stylomastoid foramen, the facial nerve gives rise to the posterior auricular branch. The facial nerve then passes through the

parotid gland The parotid gland is a major salivary gland in many animals. In humans, the two parotid glands are present on either side of the mouth and in front of both ears. They are the largest of the salivary glands. Each parotid is wrapped around the ma ...

, which it does not innervate, to form the

parotid plexus The parotid plexus or plexus parotideus is the branch point of the facial nerve (extratemporal) after it leaves the stylomastoid foramen. This division takes place within the parotid gland. Branches Commonly, it divides into the following branche ...

, which splits into five branches (temporal, zygomatic, buccal, marginal mandibular, and cervical) innervating the

Intracranial branches

The

arises at the

superior salivatory nucleus The salivatory nuclei are the superior salivatory nucleus, and the inferior salivatory nucleus that innervate the salivary glands. They are located in the pontine tegmentum in the brainstem. They both are examples of cranial nerve nuclei. The s ...

of the pons and provides parasympathetic innervation to several glands, including the

nasal glands The nasal glands are the seromucous glands in the respiratory The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and pl ...

, the

palatine glands The palatine glands form a continuous layer on the posterior surface of the mucous membrane of the soft palate and around the uvula The palatine uvula, usually referred to as simply the uvula, is a conic projection from the back edge of the midd ...

, the

, and the

pharyngeal gland Pharyngeal may refer to: Anatomy * Pharynx, for pharyngeal anatomy * Pharyngeal muscles ** Superior pharyngeal constrictor muscle ** Middle pharyngeal constrictor muscle ** Inferior pharyngeal constrictor muscle * Pharyngeal artery * Pharyngeal sl ...

. It also provides parasympathetic innervation to the

sphenoid sinus The sphenoid sinus is a paired paranasal sinus occurring within the within the body of the sphenoid bone. It represents one pair of the four paired paranasal sinuses.Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012 ...

frontal sinus The frontal sinuses are one of the four pairs of paranasal sinuses that are situated behind the brow ridges. Sinuses are mucosa-lined airspaces within the bones of the face and skull. Each opens into the anterior part of the corresponding middle ...

maxillary sinus The pyramid-shaped maxillary sinus (or antrum of Highmore) is the largest of the paranasal sinuses, and drains into the middle meatus of the nose through the osteomeatal complex.Human Anatomy, Jacobs, Elsevier, 2008, page 209-210 Structure It i ...

ethmoid sinus The ethmoid sinuses or ethmoid air cells of the ethmoid bone are one of the four paired paranasal sinuses. The cells are variable in both size and number in the lateral mass of each of the ethmoid bones and cannot be palpated during an extraoral ...

, and

nasal cavity The nasal cavity is a large, air-filled space above and behind the human nose, nose in the middle of the face. The nasal septum divides the cavity into two cavities, also known as fossae. Each cavity is the continuation of one of the two nostrils. ...

. This nerve also includes taste fibers for the

palate The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly separ ...

via the lesser palatine nerve and

greater palatine nerve The greater palatine nerve is a branch of the pterygopalatine ganglion. This nerve is also referred to as the anterior palatine nerve, due to its location anterior to the lesser palatine nerve. It carries both general sensory fibres from the maxi ...

. The communicating branch to the

otic ganglion The otic ganglion is a small parasympathetic ganglion located immediately below the foramen ovale in the infratemporal fossa and on the medial surface of the mandibular nerve. It is functionally associated with the glossopharyngeal nerve and inn ...

arises at the

and joins the

lesser petrosal nerve The lesser petrosal nerve (also known as the small superficial petrosal nerve) is the general visceral efferent (GVE) component of the glossopharyngeal nerve (CN IX), carrying parasympathetic preganglionic fibers from the tympanic plexus to the p ...

to reach the otic ganglion. The

nerve to stapedius The nerve to the stapedius is a branch of the facial nerve (CN VII) which innervates the stapedius muscle. It arises from the CN VII opposite the pyramidal eminence and passes through a small canal in this eminence to reach the stapedius muscle T ...

provides motor innervation for the

in middle ear The

provides parasympathetic innervation to the sublingual and submandibular glands, as well as special sensory taste fibers for the anterior two thirds of the tongue.

Extracranial branches

Distal to stylomastoid foramen, the following nerves branch off the facial nerve: * Posterior auricular nerve which controls movements of some of the scalp muscles around the ear * Branch to posterior belly of

digastric muscle The digastric muscle (also digastricus) (named ''digastric'' as it has two 'bellies') is a small muscle located under the jaw. The term "digastric muscle" refers to this specific muscle. However, other muscles that have two separate muscle belli ...

as well as the

stylohyoid muscle The stylohyoid muscle is a slender muscle, lying anterior and superior of the posterior belly of the digastric muscle. It is one of the suprahyoid muscles. It shares this muscle's innervation by the facial nerve, and functions to draw the hyoid ...

* Five major facial branches (at

) – from superior to inferior: ** Temporal branch ** Zygomatic branch **

Buccal branch The buccal branches of the facial nerve (infraorbital branches), are of larger size than the rest of the branches, pass horizontally forward to be distributed below the orbit and around the mouth. Branches The ''superficial branches'' run beneath ...

** Marginal mandibular branch ** Cervical branch # At the tip of tragus where the nerve is 1 cm deep and inferior # At the posterior belly of digastric by tracing this backwards to the tympanic plate, the nerve can be found between these two structures # By locating the

posterior facial vein The retromandibular vein (temporomaxillary vein, posterior facial vein) is a major vein of the face. Anatomy Origin The retromandibular vein is formed by the union of the superficial temporal and maxillary veins. Course It descends in th ...

at the inferior aspect of the gland where the marginal branch would be seen crossing it. #

Lateral semicircular canal The semicircular canals or semicircular ducts are three semicircular, interconnected tubes located in the innermost part of each ear, the inner ear. The three canals are the horizontal, superior and posterior semicircular canals. Structure The ...

# Foot of incus

Nucleus

The

cell bodies The soma (pl. ''somata'' or ''somas''), perikaryon (pl. ''perikarya''), neurocyton, or cell body is the bulbous, non-process portion of a neuron or other brain cell type, containing the cell nucleus. The word 'soma' comes from the Greek '' σῶ� ...

for the facial nerve are grouped in anatomical areas called nuclei or ganglia. The cell bodies for the afferent nerves are found in the

for taste sensation. The cell bodies for muscular efferent nerves are found in the

facial motor nucleus The facial motor nucleus is a collection of neurons in the brainstem that belong to the facial nerve ( cranial nerve VII). These lower motor neurons innervate the muscles of facial expression and the stapedius. Structure The nucleus is situate ...

whereas the cell bodies for the parasympathetic efferent nerves are found in the

Development

The facial nerve is developmentally derived from the second

pharyngeal arch The pharyngeal arches, also known as visceral arches'','' are structures seen in the embryonic development of vertebrates that are recognisable precursors for many structures. In fish, the arches are known as the branchial arches, or gill arche ...

, or branchial arch. The second arch is called the hyoid arch because it contributes to the formation of the lesser horn and upper body of the hyoid bone (the rest of the hyoid is formed by the third arch). The facial nerve supplies motor and sensory innervation to the muscles formed by the second pharyngeal arch, including the muscles of facial expression, the posterior belly of the digastric, stylohyoid, and stapedius. The motor division of the facial nerve is derived from the basal plate of the embryonic pons, while the sensory division originates from the

cranial neural crest The cranial neural crest is one of the four regions of the neural crest. The cranial neural crest arises in the anterior and populates the face and the pharyngeal arches giving rise to bones, cartilage, nerves and connective tissue. The endocraniu ...

. Although the anterior two thirds of the tongue are derived from the first pharyngeal arch, which gives rise to the trigeminal nerve, not all innervation of the tongue is supplied by it. The lingual branch of the

mandibular division In neuroanatomy, the mandibular nerve (V) is the largest of the three divisions of the trigeminal nerve, the fifth cranial nerve (CN V). Unlike the other divisions of the trigeminal nerve (ophthalmic nerve, maxillary nerve) which contain only aff ...

(V3) of the

trigeminal nerve In neuroanatomy, the trigeminal nerve ( lit. ''triplet'' nerve), also known as the fifth cranial nerve, cranial nerve V, or simply CN V, is a cranial nerve responsible for sensation in the face and motor functions such as biting and chew ...

supplies non-taste sensation (pressure, heat, texture) to the anterior part of the tongue via

general somatic afferent fibers The general somatic afferent fibers (GSA, or somatic sensory fibers) afferent fibers arise from neurons in sensory ganglia and are found in all the spinal nerves, except occasionally the first cervical, and conduct impulses of pain, touch and tempe ...

. Nerve fibers for taste are supplied by the chorda tympani branch of the facial nerve via

special visceral afferent A Special visceral afferent fibers (SVA) is a afferent fiber that develop in association with the gastrointestinal tract. They carry the special senses of smell (olfaction) and taste (gustation). The cranial nerves containing SVA fibers are the olfa ...

fibers.

Function

Facial expression

The main function of the facial nerve is motor control of all of the

. It also innervates the posterior belly of the

digastric The digastric muscle (also digastricus) (named ''digastric'' as it has two 'bellies') is a small muscle located under the jaw. The term "digastric muscle" refers to this specific muscle. However, other muscles that have two separate muscle belli ...

muscle, the

stylohyoid The stylohyoid muscle is a slender muscle, lying anterior and superior of the posterior belly of the digastric muscle. It is one of the suprahyoid muscles. It shares this muscle's innervation by the facial nerve, and functions to draw the hyoid ...

muscle, and the stapedius muscle of the

middle ear The middle ear is the portion of the ear medial to the eardrum, and distal to the oval window of the cochlea (of the inner ear). The mammalian middle ear contains three ossicles, which transfer the vibrations of the eardrum into waves in the ...

. All of these muscles are striated muscles of branchiomeric origin developing from the 2nd pharyngeal arch.

Facial sensation

In addition, the facial nerve receives

sensations from the anterior two-thirds of the

via the

. Taste sensation is sent to the gustatory portion (superior part) of the

solitary nucleus In the human brainstem, the solitary nucleus, also called nucleus of the solitary tract, nucleus solitarius, and nucleus tractus solitarii, (SN or NTS) is a series of purely sensory nuclei (clusters of nerve cell bodies) forming a vertical column ...

. General sensation from the anterior two-thirds of tongue are supplied by afferent fibers of the third division of the fifth cranial nerve (V-3). These sensory (V-3) and taste (VII) fibers travel together as the lingual nerve briefly before the chorda tympani leaves the lingual nerve to enter the tympanic cavity (middle ear) via the petrotympanic fissure. It joins the rest of the facial nerve via the canaliculus for chorda tympani. The facial nerve then forms the

, which contains the cell bodies of the taste fibers of chorda tympani and other taste and sensory pathways. From the geniculate ganglion, the taste fibers continue as the intermediate nerve which goes to the upper anterior quadrant of the fundus of the

internal acoustic meatus The internal auditory meatus (also meatus acusticus internus, internal acoustic meatus, internal auditory canal, or internal acoustic canal) is a canal within the petrous part of the temporal bone of the skull between the posterior cranial fossa ...

along with the motor root of the facial nerve. The intermediate nerve reaches the posterior cranial fossa via the internal acoustic meatus before synapsing in the

. The facial nerve also supplies a small amount of afferent innervation to the

oropharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its struc ...

below the

palatine tonsil Palatine tonsils, commonly called the tonsils and occasionally called the faucial tonsils, are tonsils located on the left and right sides at the back of the throat, which can often be seen as flesh-colored, pinkish lumps. Tonsils only present a ...

. There is also a small amount of cutaneous sensation carried by the

nervus intermedius The intermediate nerve, nervus intermedius, nerve of Wrisberg or Glossopalatine nerve, is the part of the facial nerve (cranial nerve VII) located between the motor component of the facial nerve and the vestibulocochlear nerve (cranial nerve VII ...

from the skin in and around the auricle (outer ear).

Other

The facial nerve also supplies parasympathetic fibers to the submandibular gland and sublingual glands via

. Parasympathetic innervation serves to increase the flow of saliva from these glands. It also supplies parasympathetic innervation to the nasal mucosa and the

via the

. The parasympathetic fibers that travel in the facial nerve originate in the

. The facial nerve also functions as the efferent limb of the

corneal reflex The corneal reflex, also known as the blink reflex or eyelid reflex, is an involuntary blinking of the eyelids elicited by stimulation of the cornea (such as by touching or by a foreign body), though it could result from any peripheral stimulus. S ...

Functional components

The facial nerve carries axons of type GSA,

general somatic afferent The general somatic afferent fibers (GSA, or somatic sensory fibers) afferent fibers arise from neurons in sensory ganglia and are found in all the spinal nerves, except occasionally the first cervical, and conduct impulses of pain, touch and temp ...

, to skin of the posterior ear. The facial nerve also carries axons of type GVE,

general visceral efferent General visceral efferent fibers (GVE) or visceral efferents or autonomic efferents, are the efferent nerve fibers of the autonomic nervous system (also known as the ''visceral efferent nervous system'' that provide motor innervation to smooth m ...

, which innervate the sublingual, submandibular, and lacrimal glands, also mucosa of nasal cavity. Axons of type SVE,

special visceral efferent Special visceral efferent fibers (SVE) are the efferent nerve fibers that provide motor innervation to the muscles of the pharyngeal arches in humans, and the branchial arches in fish. Some sources prefer the term "branchiomotor" or "branchial eff ...

, innervate muscles of facial expression, stapedius, the posterior belly of digastric, and the stylohyoid. The axons of type SVA,

, provide taste to the anterior two-thirds of tongue via chorda tympani.

Clinical significance

Palsy

People may suffer from

acute facial nerve paralysis Facial nerve paralysis is a common problem that involves the paralysis of any structures innervated by the facial nerve. The pathway of the facial nerve is long and relatively convoluted, so there are a number of causes that may result in facial ...

, which is usually manifested by facial paralysis. Bell's palsy is one type of

idiopathic An idiopathic disease is any disease with an unknown cause or mechanism of apparent wikt:spontaneous, spontaneous origin. From Ancient Greek, Greek ἴδιος ''idios'' "one's own" and πάθος ''pathos'' "suffering", ''idiopathy'' means approxi ...

acute facial nerve paralysis, which is more accurately described as a multiple cranial nerve ganglionitis that involves the facial nerve, and most likely results from viral infection and also sometimes as a result of

Lyme disease Lyme disease, also known as Lyme borreliosis, is a vector-borne disease caused by the ''Borrelia'' bacterium, which is spread by ticks in the genus ''Ixodes''. The most common sign of infection is an expanding red rash, known as erythema migran ...

. Iatrogenic Bell's palsy may also be as a result of an incorrectly placed dental local-anesthetic ( inferior alveolar nerve block). Although giving the appearance of a hemiplegic stroke, effects dissipate with the drug. When the facial nerve is permanently damaged due to a birth defect, trauma, or other disorder, surgery including a cross facial nerve graft or masseteric facial nerve transfer may be performed to help regain facial movement. Facial nerve decompression surgery is also sometimes carried out in certain cases of facial nerve compression.

Examination

Voluntary facial movements, such as wrinkling the brow, showing teeth, frowning, closing the eyes tightly (inability to do so is called

lagophthalmos Lagophthalmos is the inability to close the eyelids completely. Cline D; Hofstetter HW; Griffin JR. ''Dictionary of Visual Science''. 4th ed. Butterworth-Heinemann, Boston 1997. Blinking covers the eye with a thin layer of tear fluid, thereby p ...

),Kliniska Färdigheter: Informationsutbytet Mellan Patient Och Läkare, LINDGREN, STEFAN, pursing the lips and puffing out the cheeks, all test the facial nerve. There should be no noticeable asymmetry. In an

upper motor neuron Upper motor neurons (UMNs) is a term introduced by William Gowers in 1886. They are found in the cerebral cortex and brainstem and carry information down to activate interneurons and lower motor neurons, which in turn directly signal muscles t ...

lesion, called

central seven Central facial palsy (colloquially referred to as central seven) is a symptom or finding characterized by paralysis or paresis of the lower half of one side of the face. It usually results from damage to upper motor neurons of the facial nerve. T ...

, only the lower part of the face on the contralateral side will be affected, due to the bilateral control to the upper facial muscles ( frontalis and

orbicularis oculi The orbicularis oculi is a muscle in the face that closes the eyelids. It arises from the nasal part of the frontal bone, from the frontal process of the maxilla in front of the lacrimal groove, and from the anterior surface and borders of a short ...

Lower motor neuron Lower motor neurons (LMNs) are motor neurons located in either the anterior grey column, anterior nerve roots (spinal lower motor neurons) or the cranial nerve nuclei of the brainstem and cranial nerves with motor function (cranial nerve low ...

lesions can result in a CN VII palsy (Bell's palsy is the idiopathic form of facial nerve palsy), manifested as both upper and lower facial weakness on the same side of the lesion. Taste can be tested on the anterior two-thirds of the tongue. This can be tested with a swab dipped in a flavoured solution, or with electronic stimulation (similar to putting your tongue on a battery).

Corneal reflex The corneal reflex, also known as the blink reflex or eyelid reflex, is an involuntary blinking of the eyelids elicited by stimulation of the cornea (such as by touching or by a foreign body), though it could result from any peripheral stimulus. S ...

. The afferent arc is mediated by the general sensory afferents of the trigeminal nerve. The efferent arc occurs via the facial nerve. The reflex involves consensual blinking of both eyes in response to stimulation of one eye. This is due to the facial nerves' innervation of the muscles of facial expression, namely orbicularis oculi, responsible for blinking. Thus, the corneal reflex effectively tests the proper functioning of both cranial nerves V and VII.

Additional images

File:Brain human normal inferior view with labels en.svg, Inferior view of the human brain, with the cranial nerves labelled. File:Gray781.png, Mandibular division of the trifacial nerve. File:Gray788.png, Plan of the facial and intermediate nerves and their communication with other nerves. File:Gray789.png, The course and connections of the facial nerve in the

. File:Gray792.png, Upper part of medulla spinalis and hind- and mid-brains; posterior aspect, exposed in situ. File:Gray1209.png, Left temporal bone showing surface markings for the tympanic antrum (red), transverse sinus (blue), and facial nerve (yellow). File:Head facial nerve branches.jpg, Head facial nerve branches File:Slide2umr.JPG, Facial nerve. Deep dissection.

References

External links

{{Authority control Cranial nerves Motor system Innervation of the face Autonomic nervous system Gustatory system Human mouth anatomy

Structure

Intracranial branches

Extracranial branches

Nucleus

Development

Function

Facial expression

Facial sensation

Other

Functional components

Clinical significance

Palsy

Examination

Additional images

See also

References

External links