LEC53: Pathology of Cranial Nerves Flashcards
disorders in what part of brain might CNI: olfactory n be involved with?
frontal lobe, because located just under frontal lobe
what is most common cause of loss of smell
common cold, not CNI lesion
how to test if pt has CNI: olfactory n issue?
make sure pt has clear nasal paths by putting odor under nose - ensure it’s not noxious
what & where is this, & what does it cause?
meningioma on CNI: olfactory n
pt has loss of smell on 1 side
optic disc
where optic nerve enters globe
what does using opthalmoscope allow?
look into eye
look for signs of either:
1) opticatrophy
2) papilodema - swelling of the disc
what is papilodema, what does it suggest?
swellings of the optic disc
sign of increased intercranial pressure
how to test visual field?
testing CNII: optic n
move fingers to different areas in pt’s visual field; assess what they can see
what they can or cannot see tells where meningioma is
which cranial nerves are occulomotor nerves?
CNIII, IV, VI
all move the eye
what does CNIII innervate re: eye
all extraoccular muscles EXCEPT lateral rectus, superior oblique
what does CNIII do re: pupil?
CNIII involves fibers that constrict pupil
if knock out CNIII, pupil dialates
what happens if CNIII knocked out?
1) pupil dialates
2) eye deviates LATERALLY b/c CNIII doesn’t innervate lateral rectus m
3) eye deviates DOWNWARD b/c CNIII doesn’t innervate superior oblique m
which structure is CNIII?
CNIII=oculomotor n, #3
what might pressure on CNIII indicate?
brain herniation
b/c CNIII located adjacent to TEMPORAL LOBE
if anything pushes temporal lobe, will compress CNIII
what is this condition? nerve damaged?
trochlear nerve palsy - head tilted slightly
occurs b/c CNIV is a rotator; if knocked out, get slight head tilt
what is this condition?
abducens palsy - knock out of CNVI
pt gets double vision & knock out of lateral rectus m so eye cannot ABduct
can be unilateral or bilateral
what is this condition
anducens (CN VI) palsy
what optic reflex is associated with CNV, trigeminal n?
corneal reflex
NOT SCLERAL REFLEX
what is sensory field of CNV?
cause and presentation of trigeminal neuralgia?
like “seizure” of CN V
sudden, severe pain in 1 of divisions of CN V
agonizing pain caused by chewing or slightest stimulation to effected area
what does lesion of CN VII cause?
facial nerve palsy
lesion involves ALL muscles of effected side of face
what condition is this, what nerve is effected, what is presentation?
facial nerve (CN VII) palsy
1) L eye open wider b/c weakness of eye closure muscles
2) nasal labia fold more prominent on R side
3) if ask pt to show teeth, marked weakness contracting L facial muscles > see magnified asymmetry of eye fissures
what is this condition
central (woman) and peripheral (man) bell’s palsy
CN VII facial n is effected
usually 1 side of CN VII effected
what is an acoustic neuroma, which CN does it effect?
tumor on CNVIII, vestibulo-cochlear n
what is nystagmus, which CN involved?
sudden small movements of eyes
CNVIII
how to test auditory capability? which nerve tested?
CNVIII, vestibulocochlear n
make dinging sound near ear
which nerves involved with gag reflex?
CN IX, CN X
where does this pt have a lesion?
R side of CN IX glossopharyngeal, CN X vagus
uvula deviates to STRONGER side
here deviation is to L side so lesion is R side
which muscles does CNXI, accessory, innervate?
1) trapezius
2) sternocleidomastoid
drop shoulder is sign of what?
lesion to CNIX, spinal accessory n b/c innervates trapezius
what is this, what does it indicate?
scalloping on side of tongue due to atrophy of tongue muscle, innervated by CN XII, hypoglassal n
what is effected here?
R side of tongue effected b/c strong side - L - pushes tongue out toward weaker muscle
innervation = CN XII, hypoglossal
