In this article, we shall look at the anatomical course of the nerve, and the motor, sensory and parasympathetic functions of its terminal branches. The course of the facial nerve is very complex. There are many branches, which transmit a combination of sensory, motor and parasympathetic fibres. The nerve arises in the pons , an area of the brainstem. It begins as two roots; a large motor root , and a small sensory root the part of the facial nerve that arises from the sensory root is sometimes known as the intermediate nerve.
The pterygoid nerve travels through the pterygoid canal until it reaches pterygopalatine Do teen girls wank. Eye patching and artificial tears protect from corneal scarring. Butterworths; Boston: Orbicularis oris reflexalso known merve snout reflex, is produced by percussion on the upper Facial nerve diagram nose or the side of Facial nerve diagram nose nose and results in ipsilateral elevation of the angle of the mouth. The risk is greatest in children who are being treated for muscle spasticity in their necks. Clinical Significance Damage to the facial nerve can have various etiologies including iatrogenic, trauma, stroke, idiopathic Bell palsy, neoplasm or granulomatous meningitis. Musculoskeletal pain refers to pain in the muscles, bones, ligaments, tendons, and nos.
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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 Fadial transfer may be performed to help regain facial movement. Nuclei vestibular nuclei cochlear nuclei Cochlear nerve striae medullares lateral lemniscus Vestibular Scarpa's ganglion. This can be due to the absence of Facial nerve diagram nose or both nasal bones, shortened nasal bones, or nasal bones that have not fused in the midline. In addition, the facial nerve receives taste sensations from the anterior two-thirds of the tongue via the chorda tympani. Nose piercings are also common, such as in the nostril, septum, or bridge. There Facial nerve diagram nose a nasal valve area in the cavity responsible for providing resistance to the flow of air. They slowly expand within the maxillary bones and continue to expand throughout childhood. Inferior cardiac Pulmonary Vagal trunks anterior posterior. The facial nerve supplies motor and sensory innervation to the muscles formed by the second pharyngeal arch, including the muscles of facial expressionthe posterior belly of the digastric, Facil and stapedius. The Porn moviers motor doagram arises within the facial canal; the nerve to stapedius. When light enters your eye, it comes into contact with special receptors in your retina called rods and cones. The nerve arises in the facial canal, and travels across the bones of the middle ear, exiting via the petrotympanic fissureand entering the infratemporal fossa. 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 along with the motor root of the facial nerve.
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- The facial nerve is also known as the seventh cranial nerve CN7.
- The facial nerve is one of the twelve pairs of cranial nerves in the peripheral nervous system.
- Your cranial nerves are pairs of nerves that connect your brain to different parts of your head, neck, and trunk.
The facial nerve is also known as the seventh cranial nerve CN7. This nerve performs two major functions. It conveys some sensory information from the tongue and the interior of the mouth. Specifically, CN7 serves about two-thirds of the tongue's tip. The nerve extends from the brain stem, at the pons and the medulla.
Also, this nerve innervates facial muscles, controlling how to contract and produce facial expressions. During its course, CN7 splits into several branches. The greater petrosal nerve serves the lacrimal gland the gland that produces tears and the nasal cavity, as well sphenoid, frontal, maxillary, and ethmoid sinuses cavities in the skull. One of the branches provides motor signals to the stapedius muscle, which is situated in the inner ear.
The branch called the chorda tympani serves the sublingual glands a major salivary gland and the submandibular glands glands that lie under the floor of the mouth.
The chorda tympani also conveys taste sensations from the tip of the tongue. Most problems involving the facial nerve include paralysis, commonly with Bell's palsy. This condition, as well as other forms of paralysis, is sometimes triggered by a viral infection or complications of Lyme disease. Identifying your triggers can take some time and self-reflection. In the meantime, there are things you can try to help calm or quiet your anxiety….
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Distal to stylomastoid foramen , the following nerves branch off the facial nerve:. Their edges interlock by one scrolling upwards and one scrolling inwards. Genitourinary system Kidney Ureter Bladder Urethra. Both portions combine to form the vestibulocochlear nerve. From different areas of the nose superficial lymphatic vessels run with the veins and deep lymphatic vessels travel with the arteries. The oculomotor nerve has two different motor functions: muscle function and pupil response.
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Facial nerve - Wikipedia
NCBI Bookshelf. Dominika Dulak ; Imama A. Authors Dominika Dulak 1 ; Imama A. Naqvi 2. It arises from the brain stem and extends posteriorly to the abducens nerve and anteriorly to the vestibulocochlear nerve. It courses through the facial canal in the temporal bone and exits through the stylomastoid foramen after which it divides into terminal branches at the posterior edge of the parotid gland.
The facial nerve provides motor innervation of facial muscles that are responsible for facial expression, parasympathetic innervation of the glands of the oral cavity and the lacrimal gland, and sensory innervation of the anterior two-thirds of the tongue. The facial nerve carries both motor and sensory fibers. Motor axons innervate the muscles of facial expression and the stapedius muscle.
Parasympathetic fibers go to the ganglia that supply glands in the oral cavity and the lacrimal gland. The sensory component provides innervation to the external auditory meatus, the tympanic membrane, and the pinna of the ear. The facial nerve also carries taste sensation from the anterior two-thirds of the tongue.
Special visceral efferent SVE fibers branchiomotor are a major component of the facial nerve. The neurons of these fibers are localized in the facial nucleus in the caudal pontine tegmentum.
General visceral efferent GVE fibers parasympathetic preganglionic motor fibers leave the facial nerve as the greater petrosal nerve and the chorda tympani nerve. After synapsing in the pterygopalatine ganglion, the greater petrosal nerve provides postganglionic parasympathetic innervation to nasal, oral, and palatine glands.
The greater petrosal nerve supplies the lacrimal gland by giving branches to the zygomatic branch of the maxillary nerve, which later travels as the lacrimal nerve to the lacrimal gland.
These postganglionic fibers cause vasodilation and cause secretion in the lacrimal gland. The chorda tympani synapses in the submandibular ganglion and later with GVE travels as the lingual nerve, a branch of the mandibular nerve.
The lingual nerve reaches the submandibular and sublingual glands where the GVE fibers cause vasodilation and stimulate secretion. GVE preganglionic neurons are located in the superior salivatory nucleus in the brain stem. The general visceral afferent GVA component is very small. The primary sensory neurons are in the geniculate ganglion and gather sensory information via the greater petrosal nerve from the nasal cavity, part of the soft palate and the sinus cavities.
Fibers enter the brain stem with the intermediate nerve and synapse in the nucleus of the solitary tract. The special visceral afferent SVA component primarily sensory carries information about taste from the anterior two-thirds of the tongue.
Its fibers travel with the lingual nerve and the chorda tympani. The primary neurons are in the geniculate ganglion — at the genu of the facial nerve.
The fibers enter the brain via the intermediate nerve and terminate at the ipsilateral nucleus of the solitary tract in the rostral medulla. The general somatic afferent GSA component gathers sensory information from the pinna of the ear and the external acoustic meatus by forming the auricular nerve together with the vagal nerve.
Primary sensory neurons are located in the geniculate ganglion. Their central processes enter the brain stem with the intermediate nerve and terminate in the spinal nucleus of cranial nerve V. The facial nerve is derived from the second branchial arch.
The second branchial arch also produces the muscles of the face, the occipitofrontalis muscle, the platysma, the stylohyoid muscle, the posterior belly of the digastric muscle, the stapedius muscle, and the auricular muscles, all of which are innervated by CN VII.
The facial nerve exits the brain stem from its venterolateral surface at the cerebellopontine angle. It consists of two parts: a proper facial nerve and the intermediate nerve.
The proper facial nerve contains only a motor component and very small general somatic afferent component, whereas the intermediate nerve carries sensory and parasympathetic visceromotor component. The facial nerve anatomy can be divided based on its relation to the cranium and the temporal bone into intracranial, intratemporal, and extratemporal parts. The upper motor neuron UMN of the facial nerve is located in the primary motor cortex of the frontal lobe.
UMN axons descend ipsilaterally as the corticobulbar tract via the genu of the internal capsule and reach the facial nucleus in the pontine tegmentum. The facial nucleus is divided into a dorsal and ventral region. It contains the cell bodies of the facial nerve lower motor neurons LMN. The dorsal region supplies innervation of the muscles of the upper face, whereas neurons in the ventral region innervate muscles of the lower face. The dorsal aspect of the facial nucleus receives input from both the left and right cerebral hemispheres.
This results in both hemispheres having control over the muscles of the upper face. The ventral aspect of the facial nucleus receives mainly contralateral inputs. The intratemporal part of the facial nerve begins when the facial nerve, together with the intermediate nerve, passes through the internal auditory meatus of the temporal bone to enter the facial canal within the petrous part of temporal bone.
After synapsing on the geniculate ganglion, the facial nerve gives rise to the first branch; the greater petrosal nerve, which carries visceromotor parasympathetic fibers GVE to the lacrimal gland and GVA from the nasal cavity, paranasal sinuses and part of the soft palate. The second branch of the facial nerve running in the facial canal is the nerve to stapedius muscle, which provides motor SVE innervation to the stapedius muscle of the inner ear.
The chorda tympani nerve is the last branch of the facial nerve within the facial canal and at the same time, the terminal extension of the intermediate nerve. It runs through the ossicles in the middle ear and exits the tympanic cavity at the petrotympanic fissure where it joins the lingual nerve, which is itself a branch of the trigeminal nerve. Fibers from the submandibular ganglion later innervate the submandibular and sublingual glands.
The extratemporal part of the facial nerve begins when the facial nerve leaves the cranium through the stylomastoid foramen. As the facial nerve exits, it gives GSA fibers to the pinna of the ear and external auditory meatus and SVE fibers to the posterior belly of digastric, stylohyoid, the superior and inferior auricular, and occipitalis muscles.
Thereafter, the facial nerve divides at the end of the posterior edge of the parotid gland into the terminal branches. Usually, five branches can be identified:. Damage to the facial nerve can have various etiologies including iatrogenic, trauma, stroke, idiopathic Bell palsy, neoplasm or granulomatous meningitis.
It is very important not only to recognize the cause of the paralysis but also the side at which the lesion has occurred. Precise neurologic examination allows us to point to the side of the lesion with the greatest likelihood. Occurs as a result of damage to UMN of the facial nerve. The most common cause of this condition is a lacunar stroke in the posterior limb of the internal capsule.
However, UMN lesions can be caused by damage to any part of the corticobulbar tract as it travels from the primary motor cortex in the precentral gyrus of the frontal lobe. From there, the corticobulbar tract descends through the corona radiata and the anterior part of the posterior limb of the internal capsule, and then further in the crus cerebri to the caudal portion of the ventrolateral pontine tegmentum.
In the pons, axons of UMN synapse with lower motor neurons in the facial motor nucleus. As was described previously, the supranuclear innervation is bilateral to the muscles of the upper part of the face and contralateral to the muscles of the middle and lower part of the face.
UMN lesion results in paralysis of the contralateral middle and lower parts of the face with sparing of the muscles of the forehead and the orbicularis oculi muscle. Lesions that involve the facial motor nucleus or the infranuclear portion of the facial nerve result in complete paralysis of all the facial muscles on the ipsilateral side.
The patient presents with mouth droop, flattening of nasolabial fold, inability to close eye, and smoothing of the brow on the damaged side. The precise anatomic location of the lesion can be evaluated by the characteristics of the dysfunctions and involvement of associated structures:. Bell palsy is an idiopathic form of facial nerve palsy. One theory is that it is caused by edema because of a viral infection. Bell palsy can be distinguished from other causes of facial paralysis by rapid onset over several hours and lack of trauma.
What is more, this kind of facial paralysis is very often self-limiting, and the patient usually recovers within days to weeks. Residual symptoms can include facial weakness, synkinesis, tearing, and contracture. Patients can benefit from early initiation of steroids as this prevents progression of edema, diminishes chances of further damage, and speeds recovery.
There is no established evidence for use of antiviral agents. Eye patching and artificial tears protect from corneal scarring. The facial motor nucleus receives afferent information from several origins and participates in a number of reflexes:.
Corneal reflex is tested by stimulating the cornea with a wisp of cotton. It results in reflex closure of both eyelids. The afferent limb of this reflex is mediated by the trigeminal nerve, and the efferent limb is mediated by the facial nerve. Orbicularis oculi reflex can be evoked by various stimuli such as stimulation of the supraorbital nerve, light, and sound.
The afferent limb of this reflex is mediated by the trigeminal, optic and vestibulocochlear nerves respectively. The efferent limb is mediated by the facial nerve and produces bilateral eye blink. Orbicularis oris reflex , also known as snout reflex, is produced by percussion on the upper lip or the side of the nose and results in ipsilateral elevation of the angle of the mouth.
The trigeminal nerve stands for the afferent limb and the facial nerve for the efferent limb of the reflex. Orbicularis oris reflex can be evoked in infants and disappears later in life. It can recur in the setting of the supranuclear facial nerve lesion and extrapyramidal diseases like Parkinson disease.
To access free multiple choice questions on this topic, click here. Branches and components of the facial nerve. Contributed by Dominika Dulak. This book is distributed under the terms of the Creative Commons Attribution 4.
Turn recording back on. National Center for Biotechnology Information , U. StatPearls [Internet]. Search term. Affiliations 1 Gdansk Medical University. Structure and Function The facial nerve carries both motor and sensory fibers. Embryology The facial nerve is derived from the second branchial arch.
Nerves The facial nerve exits the brain stem from its venterolateral surface at the cerebellopontine angle.