CN VII and VIII (Facial and Vestibulocochlear Nerves) Flashcards
The facial nerve (CN VII) is derived from the ___ pharyngeal arch
2nd
The facial nerve arises from the facial nerve nucleus in the ____ pons
ventrolateral
The motor portion of the facial nerve enters the petrous temporal bone via the ____ ____ ____ then runs a tortuous course through the ____ canal, where it continues laterally between the internal and middle ears
internal auditory meatus; facial
After passing through the facial canal, the facial nerve bends posteriorly and laterally forming a _____ ganglion
sensory (geniculate)
After forming the geniculate ganglion, the facial nerve bends sharply downward, almost in a vertical course to emerge from the _____ foramen reaching the ____ gland, where it divides into 5 major branches
stylomastoid; parotid
This branch of the facial nerve is the only intracranial branch
nerve to the stapedius muscle
This branch of the facial nerve supplies the occipital belly of the occipitofrontalis muscle
posterior auricular nerve
True or false? a branch of the facial nerve supplies the posterior belly of digastric and the stylohyoid muscle
true
In the parotid gland, the facial nerve divides into 5 major branches (TZBMC). What does the temporal branch supply?
crosses the zygomatic arch to supply the superior and anterior auricular, the frontal belly of the occipitofrontalis muscle, and the superior part of the orbicular oculi
In the parotid gland, the facial nerve divides into 5 major branches (TZBMC). What do the zygomatic branches supply?
muscles inferior to eye
In the parotid gland, the facial nerve divides into 5 major branches (TZBMC). What does the buccal branch supply?
buccinator, muscles of upper lip
In the parotid gland, the facial nerve divides into 5 major branches (TZBMC). What does the marginal mandibular branch supply?
risorius and muscles of the lower lip and chin
In the parotid gland, the facial nerve divides into 5 major branches (TZBMC). What does the cervical branch supply?
platysma
The _____ _____ or “nerve of Wrisberg” is the part of the facial nerve located between the motor component of the facial nerve and the vestibulocochlear nerve. It contains the parasympathetic and sensory fibers of the facial nerve.
nervus intermedius
Upon reaching the facial canal, the nervus intermedius joins with the motor root of the facial nerve at the ____ ganglion
geniculate
The _____ _____ nucleus contains cell bodies of parasympathetic preganglionic axons. These axons are called the nervus intermedius.
superior salivatory
note: these fibers reach the geniculate ganglion but do not synapse
Some of the preganglionic parasympathetic fibers of nervus intermedius persist within the ____ ____ nerve as they exit the geniculate ganglion and subsequently synapse with neurons in the _____ ganglion
greater petrosal; pterygopalatine
The postganglionic neurons of the nervus intermedius send axons that provide parasympathetic innervation to the vessels, and glands of the nasal cavity, maxillary sinus, palate, and ____ gland
lacrimal
The remaining preganglionic fibers from the nervus intermedius continue as the mixed facial nerve proper as it extends through the facial canal. Before the nerve exits the skull and after the nerve to stapedius muscle has branched off, the facial nerve gives off the ____ ____ nerve
chorda tympani
The chorda tympani exits the skull through the _____ ____ to merge with the ____ nerve
petrotympanic fissure; lingual
After merging with the lingual nerve, the chorda tympani nerve synapses with neurons in the ____ ganglion
submandibular
Tast fibers from the anterior 2/3 of the tongue, floor of the mouth, and the palate are carried along the ____ ____ nerve
chorda tympani (via the lingual nerve)
The chorda tympani nerve joins the facial nerve inside the ___ ____
facial canal
The ____ ganglion contains the cell bodies of the sensory component of the nervus intermedius, including taste fibers from the chorda tympani
geniculate
The ____ nucleus is a series of nuclei forming a vertical column of grey matter embedded in the ____ _____
medulla oblongata
The ____ portion of the solitary complex is a component of the taste pathway carried within the chorda tympani nerve
rostral
The axons within the rostral tractus solitaires are the central process of cells from three cranial nerve ganglia, including the ____ ganglion
geniculate
The general sensory component of the nervus intermedius carries sensation from the skin of the external auditory meatus, from the mucous membrane of the nasopharynx and nose via the ____ ____ nerve
greater petrosal
note: somatic afferents from these areas arise form the caudal position of the solitary complex
This disorder is caused by the reactivation of herpes zoster virus in the geniculate ganglion. Patients present with the inability to move any facial muscles, pain in the ear, loss of taste from the anterior 2/3 of tongue, dry ears and mouth, and rash
Ramsay Hunt Syndrome type 2
____ ____ is a pain syndrome associated with the nervus intermedius
geniculate neuralgia
Injury to branches of the facial nerve causes paralysis of the facial muscle (____ ____) with or without loss of taste or altered secretion from lacrimal or salivary gland
bell’s palsy
Lesions near the origin of the facial nerve from the pons or proximal to the origin of the greater petrosal nerve (region of the geniculate ganglion) result in what?
loss of motor, taste, and autonomic (lacrimal and salivary secretions) functions and difficulty tolerating every day sounds (hyperacusis)
Lesions distal to the geniculate ganglion, but proximal to the origin of the nerve to stapedius result in what?
same dysfunction as before except that lacrimal secretion is not affected
Lesions istal to the origin of the nerve to stapedius, but proximal to the origin of the chorda tympani nerve result in what?
same dysfunction as before except that lacrimal secretion is not affected and hyperacusis is not present
Lesions distal to the origin of chorda tympani, near the stylomastoid foramen result in what?
loss of motor function only (paralysis of facial muscles)
What is the most common non traumatic cause of facial nerve palsy?
inflammation of the facial nerve near the sytlomastoid foramen due to viral infection
Facial nerve palsy may be ____ but it often follows exposure to ____
idiopathic; cold
A lesion of the ____ branch of the facial nerve causes paralysis including loss of tone of the orbicularis oculi in the inferior eyelid leading to eversion of the inferior eyelid so that the lacrimal fluid is not spread over the cornea leading to dryness and sometimes ulceration
zygomatic
Paralysis of the buccal branch of the facial nerve causes paralysis of what?
buccinator and superior portion of orbicularis oris and upper lip muscles
Paralysis of the marginal mandibular branch of facial nerve causes paralysis of what?
the inferior portion of the orbicularis oris and lower lip muscles
The actual sensory receptors of the vestibulocochlear nerve are the ____ ___ cells
inner hair
note: outer hair cells are amplifiers
The cochlear nerve relays with the first order sensory cells in the ____ ganglia which are in the base of the spiral lamina
spiral
The superior division of the vestibular nerve carries sensory fibers from the hair cells of the anterior and lateral ____ canals and ____
semicircular; utricle
The inferior division of the vestibular nerve carries sensory fibers from the ____
saccule
Where does the cochlear nerve run with the superior and inferior divisions of the vestibular nerve?
internal acoustic meatus
The vestibulocochlear nerve enters between the ____ and ____ lateral to the facial nerve and nervus intermedius, passing laterally though the ____ angle
pons; medulla; cerebellopontine
Clinical correlate: the cerebellopontine angle is a common site for the growth of what?
acoustic neuromas or schwanomas which can affect V, VII, and VIII
There are two cochlear nuclei that lie dorsal lateral and ventral lateral to the ____ ____ ____ at the rostral pole of the medulla
inferior cerebellar peduncle
How many vestibular nuclei are located in the brainstem?
4
Lesions of CN VIII (vestibulocochlear) may cause what?
tinnitus (ringing), vertigo, and loss of hearing
There are two kinds of deafness: conductive deafness and sensorineural deafness. Describe each.
conductive: involves external or middle ear
sensorineural: disease in the cochlea
An ____ ____ is a slow-growing benign tumor of the neurolemma (schwann) cells. The tumor begins in the vestibular nerve while its is in the internal acoustic meatus.
acoustic neuroma
people with head trauma often experience heartache, dizziness, vertigo, and a spinning sensation. These symptoms, often accompanied by nausea and vomiting, are usually related to what type of lesion?
peripheral vestibular nerve lesion
