CN VII-XII Flashcards
what muscles does CN VII innervate?
all muscles of facial expression as well as taste sensitivity to the anterior 2/3 of the tongue (sweet, sour, salty)
the corticobulbar tract controls…
volitional movements of he forehead musculature equally from each cerebral hemisphere
what is usually spared in unilateral lesions involving corticobulbar pathways?
forehead movement
the lower face requires ____movement, therefore it receives a greater percentage of ____observation and _____lesions may have long term effects
unilateral
contralateral
contralateral
CN VII innervates what muscle?
stapedius
what is the function of the the stapedius?
dampen movement of tympanic membrane
stimulation of the parasympathetic fibers cause increased secretion of ____saliva
thin and watery
stimulation of sympathetic fibers cause increased secretion of _____saliva
thick and turbid
bell’s palsy
a condition that causes facial paralysis and is considered a LMN lesion (all ipsilateral facial muscles distal to the lesion are affected)
stroke
a type of facial paralysis, gradient of facial weakness due to bilateral innervations
Forehead is spared
examination of CN VII
instruct patient to look up and check fro symmetry in head wrinkles (note drooling, dysarthria, dysphagia)
the receptors are located in what part of the ear?
semicircular canals, utricle and saccule of middle ear
describe the pathway sound gets to the ear
impulses are carried to the vestibular ganglia and pass through the vestibular nerve
vestibular nerve through internal auditory meatus to brainstem and terminate on 4 of vestibular nuclei OR
pass through the inferior cerebellar peduncle as part of the vestibulocerebellum
what conflicting information will result in nystagmus?
CN II, IV or VI and CN VIII
the receptors of the cochlear division are located where?
organ of corti in the cochlea
hypoacusis with or without tinnitius is probably from…
conduction loss, receptor disease or lesion affecting CN VIII
hypoacusis
partial loss of hearing
hyperacusis
increased sensitivity to certain frequency and vlume ranges of sound
hyperacusis can be due to…
CN VII disorder or centrally located problem
there are 2 major varieties of hearing loss
conductive and sensorineural
common etiologies for conductive hearing loss
auditory canal obstruction
direct/indirect trauma to tympanic membrane
trauama/aging of ossicles
accumulation/fluid in middle ear
sensorineural hearing loss is typically treated to…
disease of organ of corti or auditory nerve
what do you assess for when testing the vestibular division of CN VIII?
signs of vertigo
unsteadiness with or without falling, nystagmus, pallor, sweating, vomiting and hypotension
the side toward which the fast component of nystagmus occurs…
on the side which the nystagmus is named
carloric irrigation
utilizes warm (103-110F) or cold (drops/ice) water
COWS
cold opposite
warm same
explain the mechanism of a positive swivel chair test
holding head keeps vestibulocochlear proprioceptors inactivated, therefore only activating cervical proprioceptors
what are the four cochlear divisions tests?
observation of external and internal ear
weber and rinne test
what are the two tests of the vestibular division?
swivel chair tests, caloric irrigation
what do you do with the earlobe during an adult otoscopic exam?
pull ear up and back
what do you do with the earlobe during a child otoscopic exam?
pull ear down and out
weber’s test lateralizes to the right, what are the findings?
right air conduction deafness or left sensorineural deafness
weber’s test lateralizes to the right and rinne’s on the right was 10:10 (bone conduction:air conduction) and on the left was 10:20, what are the findings?
right air conduction deafness
weber lateralizes to the right and rinne’s on the right was 10:20 (bone conduction:air conduction) and on the left was 10:10, what are the findings?
sensorineural deafness on the left
weber’s test lateralizes to the right and rinne’s on the right was 10:20 (bone conduction:air conduction) and on the left was 2:4 (bone conduction:air conduction), what are the findings?
sensorineural deafness on left
review picutres of otoscopic pictures
normal red reflex foreign body in ear acute otitis media suppurative otitis media tympanostomy tube perforated tympanic membrane
CN IX and X innervate what muscle?
stylopharyngeus
stylopharyngeus
elevates the pharynx and larynx as well as aids in raising the soft palate
CN X action
helps with active swallowing and articulation as a unilateral paralysis of CN X will be followed by tranient paresis of the soft palate, pharynx and larynx on the affected side along with absent gag reflexes and absens ocular cardiac reflex
what happens with bilateral CN X paralysis
it is not compatible with life
dysarthria
faulty articulation
dysphagia
difficulty swallowing
hypernasal
increased air entering the nasal pathway
hyponasal
decreased air entering nasal pathway
What are the tests for CN IX and X?
have the patient say AHH and watch for bilateral elevation of soft palate
say ku-lah-me
gag reflex
gag reflex
touch the base of the tongue, the initiation of the gag reflex is sensory portion of cranial nerve IX and the motor function of CN X
tests for CN XI
muscle strength of trap and SCM
SCM actions
tilt head to the same side
turn chin to opposite side
flex head when contracted bilaterally
trapezius actions
tilt head to same side
turn chin to opposite side
elevate shoulder when contracted bilaterally
fibers of CN XII originate in what nucleus? where does it emerge?
hypoglossal nuclei
emerge from the bottom of the brainstem
what are the tests for CN XII
have patient stick out the tongue
have patient do tongue in cheeck test
a lesion involving the R CN XII will cause the tongue to what?
deviate to the left
what do you look out for when the patient sticks out the tongue?
fasciculations