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Anatomy - BB Exam 3 > Cranial Nerves > Flashcards

Cranial Nerves Flashcards

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1
Q

which cranial nerves are especially susceptible to compression or injury related to pathologies of sinus? why?

A

3, 4, V1, 6 - due to close relationship to cavernous sinus

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2
Q

anosmia

A

loss of smell

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3
Q

things associated with anosmia

A
  • upper respiratory infection
  • sinus disease
  • head trauma
  • aging
  • tumor/abscess in frontal lobe
  • tumor of meninges in anterior cranial fossa
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4
Q

what do people usually complain of w/ anosmia and why?

A

lost or altered taste - b/c most people confuse taste with flavor

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5
Q

allergic rhinitis

A

inflammation of nasal mucous membrane - causes transitory olfactory impairment

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6
Q

how do you test for sense of smell?

A

person blindfolded and asked to ID common odors, like coffee

-test each nostril separately b/c anosmia is usually unilateral

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7
Q

rhinorrhea

A

leakage of fluid through the nose

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8
Q

meningioma

A

tumor of meninges

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9
Q

what are olfactory hallucinations and when can you get them?

A

false perceptions of smell - lesions in temporal lobe

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10
Q

what could a lesion of lateral olfactory area, deep to uncus, cause?

A

temporal lobe epilepsy/uncinate fits - imaginary bad odors + involuntary movements of lips and tongue

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11
Q

what can cause CN I lesion that causes anosmia and CSF rhinorrhea?

A

fracture of cribriform plate

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12
Q

what can cause CN II lesion that causes loss of pupillary constriction? (2 things)

A
  • direct trauma to orbit or eyeball

- fracture involving optic canal

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13
Q

what can cause CN II lesion that results in visual field defects? (2 things)

A
  • pressure on optic pathway

- laceration or intracerebral clot in temporal, parietal, or occipital lobes

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14
Q

what can cause CN III lesion that results in:
-dilated pupil
-ptosis
-eye turns down and out
-pupillary reflex on side of lesion lost
(3 things)

A
  • pressure from herniating uncus on nerve
  • fracture involving cavernous sinus
  • aneurysms
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15
Q

what can cause CN IV lesion that results in inability to look down when eye is adducted? (2 things)

A
  • stretching of nerve during its course around brainstem

- fracture of orbit

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16
Q

what can cause CN V lesion that results in:
-loss of pain and touch sensations
-paresthesia
-masseter and temporalis mm. do not contract
-deviation of mandible to side of lesion w/ open mouth
(2 things)

A
  • injury to terminal branches (particularly V2) in roof of maxillary sinus
  • pathological processes affecting trigeminal ganglion
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17
Q

what can cause CN VI lesion that results in:
-eye fails to move laterally
-diplopia on lateral gaze
(2 things)

A
  • lesion of base of brain

- fracture involving cavernous sinus or orbit

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18
Q

what can cause CN VII lesion that results in:

  • paralysis of facial muscles
  • eye remains open
  • angle of mouth droops
  • forehead does not wrinkle
A

laceration or contusion in parotid region

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19
Q

what can cause CN VII lesion that results in:

  • paralysis of facial muscles
  • eye remains open
  • angle of mouth droops
  • forehead does not wrinkle
  • associated involvement of cochlear n. and chorda tympani
  • dry cornea
  • loss of taste on anterior 2/3 of tongue
A

fracture of temporal bone

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20
Q

what can cause CN VII lesion that results in:

  • forehead wrinkles b/c of bilateral innervation of frontalis
  • otherwise paralysis of contralateral facial muscles
A

intracranial hematoma “stroke”

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21
Q

what can cause CN VIII lesion that results in:

  • progressive unilateral hearing loss
  • tinnitus
A

tumor of nerve (acoustic neuroma)

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22
Q

what can cause CN IX lesion that results in:
-loss of taste on posterior 1/3 of tongue
-loss of sensation on affected side of soft palate
(2 things)

A
  • brainstem lesion

- deep laceration of neck

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23
Q

what can cause CN X lesion that results in:
-sagging of soft palate
-deviation of uvula to normal side
-hoarseness owing to paralysis of vocal fold
(2 things)

A
  • brainstem lesion

- deep laceration of neck

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24
Q

what can cause CN XI lesion that results in:

  • paralysis of SCM and descending fibers of trapezius
  • drooping of shoulder
A

laceration of neck

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25
what can cause CN XII lesion that results in: -protruded tongue deviates toward affected side -moderate dysarthria (disturbance of articulation) (2 things)
- neck laceration | - fractures of cranial base
26
what nerve is susceptible to demyelinating diseases of CNS and why? what is an example of one such disease?
optic nerves - they are actually CNS tracts - myelin sheath formed by oligodendrocytes instead of Schwann cells -MS (multiple sclerosis)
27
optic neuritis
lesions of the optic nerve that cause diminution of visual acuity, w/ or w/o changes in peripheral fields of vision -optic disc is pale and smaller than normal
28
what can cause optic neuritis?
inflammatory, degenerative, demyelinating, or toxic disorders
29
what causes visual field defects?
lesions that affect different parts of visual pathway
30
what visual field defects result from complete section of an optic nerve?
blindness in the temporal and nasal visual fields of the ipsilateral eye
31
what visual field defects result from complete section of the optic chiasm?
reduces peripheral vision - bitemporal hemianopsia (loss of vision of 1/2 of the visual field of both eyes
32
what visual field defects result from complete section of the right optic tract at the midline?
eliminates vision from left temporal and right nasal visual fields - contralateral homonymous hemianopsia (visual loss in similar fields)
33
what is the most common type of visual field loss and in what patients is it often seen?
contralateral homonymous hemianopsia (section or either right or left nerve) - seen in stroke patients
34
what does a lesion of CN III result in?
ipsilateral oculomotor palsy
35
CN III compression: where can it be compressed, and what is the first sign?
- crest of petrous part of temporal bone | - ipsilateral slowness of pupillary response to light
36
what can cause CN III compression?
- rapid increase in intracranial pressure (from extradural hematoma) - aneurysm of a posterior cerebral or superior cerebellar artery - injuries or infections of cavernous sinus
37
characteristic sign of a trochlear nerve injury
diplopia when looking down - b/c SO normally assists the IR in depressing pupil and is the only muscle to do so when pupil is adducted
38
how can a patient compensate for diplopia caused by trochlear nerve injury?
inclining head anteriorly and laterally toward side of the normal eye
39
what does injury to CN V cause? (4 things)
- paralysis of muscles of mastication w/ deviation of mandible towards side of lesion - loss of ability to appreciate soft tactile, thermal, or painful sensations on face - loss of corneal reflex - loss of sneezing reflex
40
what are common causes of facial numbness? (6 things)
- dental trauma - herpes zoster ophthalmicus - cranial trauma - head and neck tumors - intracranial tumors - idiopathic trigeminal neuropathy
41
trigeminal neuralgia is also called?
tic douloureux
42
what is trigeminal neuralgia/ tic douloureux?
produces excruciating, episodic pain that is usually restricted to areas supplied by the maxillary and/or mandibular divisions of trigeminal n. (from compression of nerve)
43
what is the principal disease of the sensory root of CN V?
tic douloureux
44
which nerve is most often blocked during dental anesthesia administration?
inferior alveolar nerve from V3
45
what does complete paralysis of CN VI cause?
- medial deviation of affected eye due to unopposed action of MR m. - diplopia always
46
what can cause CN VI paralysis? (4 things)
- space occupying lesion, such as brain tumor - aneurysm of cerebral arterial circle - pressure from an atherosclerotic internal carotid a. in the cavernous sinus - septic thrombosis of sinus subsequent to infection in nasal and/or paranasal cavities
47
what is the most frequently paralyzed of motor CNs?
CN VII
48
what does a lesion of CN VII near it's origin or near geniculate ganglion cause?
- loss of motor, gustatory, and autonomic functions | - motor paralysis on superior and inferior ipsilateral parts of face
49
what does a central lesion of CN VII cause?
- motor paralysis on contralateral inferior face | - can still wrinkle forehead
50
Bell's palsy
unilateral facial paralysis of sudden onset resulting from a lesion of CN VII
51
what can lesions of CN VIII cause?
- tinnitis - vertigo - impairment/loss of hearing
52
two kinds of deafness?
1. conductive deafness: involves external or middle ear | 2. sensorineural deafness: involves disease in cochlea or in pathway from cochlea to brain
53
acoustic neuroma
neurofibroma - slow-growing benign tumors of Schwann cells that begins in the vestibular nerve while in the internal acoustic meatus
54
symptoms of acoustic neuroma
- loss of hearing (early symptom) - dysequilibrium - tinnitis
55
vertigo
hallucination of movement involving the person or the environment - often a spinning sensation or swaying back and forth - comes w/ nausea, vomiting
56
what type of nerve lesion is vertigo typically associated with?
peripheral vestibular nerve lesion
57
losses in isolated CN IX lesion?
- no taste on posterior 1/3 of tongue - no gag reflex - ipsilateral weakness - change in swallowing
58
jugular foramen syndrome
tumors in region of jugular foramen produce multiple cranial nerve palsies - IX, X, XI all run through jugular foramen
59
glossopharyngeal neuralgia
sudden intensification of burning or stabbing pain often initiated by swallowing, protruding tongue, talking, or touching palatine tonsil - uncommon - unknown cause
60
what do injury to pharyngeal branches of CN X cause?
dysphagia
61
what does injury to superior laryngeal nerve cause?
- anesthesia of superior part of larynx - paralysis of cricothyroid muscle - weak voice that tires easily
62
what does injury to recurrent laryngeal nerve cause?
-hoarseness -dysphonia (difficulty speaking) (paralysis of vocal cords)
63
what does paralysis of both recurrent laryngeal nerves cause?
- aphonia - loss of voice | - inspiratory stridor
64
what is inspiratory stridor?
harsh, high pitched respiratory sound
65
which recurrent laryngeal nerve is more commonly injured and why?
left - b/c of its longer course
66
iatrogenic injury of CN XI
physician-caused injury that may occur during surgical procedures such as: - lymph node biopsy - cannulation of internal jugular vein - carotid endarterectomy
67
what does injury to CN XII do?
paralyzes ipsilateral half of tongue | -atrophy of that side of tongue
68
which side does the tongue protrude to in CN XII injury?
-protruded tongue deviates toward paralyzed side b/c of unopposed action of the genioglossus muscle on normal side of tongue

Anatomy - BB Exam 3 (13 decks)

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