Cranial Nerves Flashcards

1
Q

Cranial nerve 1 origin

A

Olfactory

Cerebrum

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2
Q

CN 1 exit skull

A

Cribriform plate

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3
Q

CN 1 modality /components

A

Special visceral Sensory (senses derived from endoderm)

Smell

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4
Q

CN II origin

A

Cerebrum

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5
Q

CN II exit skull

A

Optic canal

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6
Q

CN 2 modalities/components

A

Special somatic sensory (senses derived from ectoderm)

Sight

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7
Q

CN 3 origin

A

Midbrain - pontine junction

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8
Q

CN 3 components/modality

A

Motor
General somatic motor: 4 extrinsic eye muscles and levator palpebrae superioris
General visceral motor: parasympathetic to pupillary sphincter and ciliary m

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9
Q

CN 3 exit skull

A

Superior orbital fissure

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10
Q

CN 4 origin

A

Midbrain posterior (longest intracranial length of all CNs)

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11
Q

CN4 exit skull

A

Superior orbital fissure

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12
Q

CN4 modality/components

A

Motor

General somatic motor: superior oblique

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13
Q

CN V origin

A

Pons

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14
Q

CN 5.1 exit skull

A

Superior orbital fissure

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15
Q

Ophthalmic nerve modality/components

A

General somatic sensory (skin): scalp, forehead, nose

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16
Q

CN 5.2 exit skull

A

foramen rotundum

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17
Q

Maxillary nerve modality/ components

A

General somatic sensory: cheeks, lower eye lid, nasal mucosa, upper lip, upper teeth, palate

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18
Q

CN 5.3 exit skull

A

Foramen ovale

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19
Q

Mandibular nerve modality/ components

A

General somatic sensory: anterior 2/3 tongue, skin over mandible, lower teeth
Special visceral motor (mm derived from pharyngeal arches) :muscles of mastication, tensor tympani muscle

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20
Q

CN 6 origin

A

Pontine - medulla junction

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21
Q

CN 6 exit skull

A

Superior orbital fissure

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22
Q

CN6 modality/components

A

General somatic motor: lateral Rectus

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23
Q

CN 7 origin

A

Pontine-medulla junction

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24
Q

CN 7 exit skull

A

Internal acoustic meatus

Stylomastoid foramen

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25
Q

CN 7 modality/components

A

Motor and sensory
General somatic sensory: external ear . stapedius mm
Special visceral sensory: taste ant 2/3 tongue, hard and soft palate
Special visceral motor: muscles facial expression
General visceral motor: parasympa- lacrimal, submandibular, sublingual, mucous glands of mouth and nose.

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26
Q

CN 8 origin

A

Pontine- medullary junction

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27
Q

CN8 exit skull

A

Internal acoustic meatus

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28
Q

CN8 modality/components

A

Special somatic sensory: hearing and balance

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29
Q

CN IX origin

A

Medulla oblongata posterior to olive

30
Q

CN IX exit skull

A

Jugular foremen

31
Q

CN IX modality/components

A

Motor and sensory
General somatic sensory: posterior 1/3 tongue, external ear, middle ear cavity
General visceral sensory: carotid body and sinus
Special visceral Sensory: taste post 1/3 tongue
General visceral motor: parotid gland parasympa
Special visceral motor: stylopharyngeus

32
Q

CN X origin

A

Medulla oblongata posterior to the olive

33
Q

CN X exit skull

A

Jugular foramen

34
Q

CN X modality/components

A

Motor and sensory (vagus)
General somatic sensory: external ear, larynx, pharynx
General visceral sensory: larynx, pharynx, thoracic and abdominal viscera
Special visceral sensory: taste from epiglottis region of tongue
General visceral motor: parasympa. smooth muscles pharynx, larynx, most of GIT. Palatoglossus
Special visceral motor: most muscles pharynx and larynx

35
Q

CNXI origin

A

Medulla oblongata posterior to olive

36
Q

CN XI exit skull

A

Jugular foramen

37
Q

CN XI modality/components

A

Motor
General somatic motor: trapezius, sternocleidomastoid
Special visceral motor: a few fibres run with CNX to viscera

38
Q

CNXII origin

A

Medulla oblongata anterior to olive

39
Q

CNXII exit skull

A

Hypoglossal canal

40
Q

CN XII modality/components

A

General somatic motor: intrinsic and extrinsic muscles of tongue, except palatoglossus (CNX)

41
Q

How test olfactory nerve

A

Ask if any changes in smell

42
Q

How test optic nerve (8)

A
  • Pupil size, symmetry and shape
  • visual acuity with Snellen chart!
  • direct and consensual pupillary reflex!
  • swinging light test to check for relative afferent pupillary defect (Marcus Gunn pupil) (positive = paradoxical dilatation of affected pupil when light shone into it)
  • Accommodation reflex: pupillary convergence and constriction when focus from far object to finger!
  • colour vision using Ishihara plates at arms length
  • visual fields: pt cover one eye and you mirror patient. Your finger equal distance between you and patient. Bring closer to test peripheral visual field! Ask if can see your face to check for central scotoma . Then how many hands do they see to test for hemisnopia eg. Then how many fingers in each visual field. Then how many fingers total for visual neglect. Then tell me when you can see my finger for periph field.
    Do opposite to test blind spot
  • fundoscopy!
43
Q

Describe the muscles responsible for the eye movements (6)

A

Up: superior rectus and inferior oblique

Down: inferior rectus, superior oblique

Adduction: medial rectus (and secondary action of superior rectus, inferior rectus)

Abduction: lateral rectus, superior oblique, inferior oblique

Medial rotation: superior oblique (superior rectus)

Lateral rotation: inferior oblique (inferior rectus )

44
Q

Function superior rectus?

A

Primary: elevation
Secondary: adduction, medial rotation

45
Q

Function inferior rectus?

A

Primary: depression
Secondary: adduction, lateral rotation

46
Q

Function medial rectus?

A

Adduction

47
Q

Function lateral rectus?

A

Abduction

48
Q

Function superior oblique?

A
  • depress
  • abduct
  • medial rotation
49
Q

Function inferior oblique?

A
  • Elevate
  • Abduct
  • laterally rotate
50
Q

How test trigeminal nerve (6)

A

Sensory

  • light touch and pinprick of forehead (ophthalmic division v1 ) , cheek (maxillary v2 ), lower jaw (mandibular V3)

Motor: muscles of mastication

  • masseter muscle (clench teeth)
  • temporalis muscle
  • lateral and medial plerygoid muscles (open and close jaw against resistance )

Reflexes

  • jaw jerk reflex
  • corneal reflex
  • nasal tickle
51
Q

How test facial nerve (10)

A

Sensory

  • ask if taste changes (anterior 2/3 of tongue)

Motor

  • ask if hearing changes (stapedius muscle. Paralysis = hyperacusis )
  • frontalis muscle: raise eyebrows
  • orbicularis oculi: scrunched eyes
  • buccinator: blow out cheeks
  • levator anguli oris and zygomaticus major: smile
  • buccinator and orbicularis oris: pursed lips (whistle)
  • platysma

Autonomic

  • lactimation
  • salivation
52
Q

How test vestibulocochlear nerve (5)

A

Sensory only

  • ask if change in hearing
  • whisper word from 60 cm away
  • Rinne and Weber’s test
  • turning test: patient march on spot with arms out and eyes closed. If vestibular lesion, will turn towards side of lesion
  • Vestibular-ocular reflex: patient fixate on your nose throughout. Use your hands to rapidly rotate their head each way. Should maintain ocular fixation.
53
Q

How test glossopharyngeal nerve (3)

A

Motor

  • stylopharyngeus muscle: elevates pharynx during swallow and speech
    (Afferent limb of swallow)

Sensory

  • taste post 1/3 tongue

Reflex

  • afferent limb of gag reflex
54
Q

How test vagus nerve (5)

A

Motor

  • speech
  • say “ahh” and inspect soft palate and uvula. Lesion = deviate to normal side
  • cough: lesion = weak, non-explosive bovine cough
  • swallow: efferent limb

Reflex

  • efferent limb of gag reflex
55
Q

How test accessory nerve (2)

A

Motor

  • sternocleidomastoid: palpate both heads
  • trapezius
56
Q

How test hypoglossal nerve (3)

A

Motor to extrinsic muscles of tongue except palatoglossus (vagus)

  • fasciculation’s and wasting while tongue in mouth
  • protrude: deviation (will deviate to side of lesion)
  • push pt tongue against cheek
  • speed of tongue movement
57
Q

How does CN iii palsy present

A
  • Down and out (unopposed action of lateral rectus and superior oblique)
  • Ptosis (levator palpebrae superioris)
  • mydriasis (loss of parasympathetic fibres to sphincter pupillae muscle)
    (With: surgical 3rd nerve palsy, without: medical 3rd nerve palsy )
58
Q

How does CN iv palsy present

A
  • Vertical diplopia, often compensated for by tilting head forward and tucking chin in
  • Torsional diplopia compensated by tilting head to other side
59
Q

How does CN vi palsy present

A

Convergent squint and horizontal diplopia

60
Q

Define exotropia

A

Eye at rest: laterally
Cover test direction of shift: medially

61
Q

Define esotropia

A

Eye at rest: medial
Cover test direction of shift: laterally

62
Q

Define hypertropia

A

Eye at rest: up
Cover test direction of shift: down

63
Q

Define hypotropia

A

Eye at rest: Down
Cover test direction of shift: up

64
Q

How does facial nerve palsy caused by lower motor neuron present and example

A
  • Weakness of all ipsilateral muscles of facial expression
  • Bell’s palsy
65
Q

How does facial nerve palsy caused by upper motor neuron lesion present and example

A
  • Unilateral facial weakness with sparing of upper facial muscles ( frontalis)
  • stroke
66
Q

Name features Bell’s palsy (5)

A

= CN VII LMN palsy

  • Weakness of all ipsilateral muscles of facial expression
  • decreased/ absent lacrimation
  • hyperacuses
  • Loss taste anterior 2/3 tongue
  • Vesicles external ear canal and lobe due to herpes zoster infection
67
Q

Name the near triad of accommodation

A
  • Convergence
  • miosis
  • accommodation of lens
68
Q

Name the afferent and efferent limbs of the corneal reflex

A

Afferent: cn V
Efferent: cn vii (orbicularis oculi)

69
Q

Define bulbar palsy

A

Impaired function of cranial nerves 9, 10,11 and 12.
All originate in medulla oblongATA

70
Q

Describe innervation of the tongue

A

Sensory

  • anterior 2/3: trigeminal Nerve (mandibular division, lingual nerve)
  • posterior 1/3 : glossopharyngeal Nerve

Taste

  • anterior 2/3: facial nerve (chorda tympani)
  • posterior 1/3 : glossopharyngeal Nerve
71
Q

Name 6 causes LMN CN VII lesions

A
  • vascular: cerebrovascular ischaemia
  • idiopathic: Bell’s palsy (pregnancy, DM)
  • nerve; posterior fossa tumours
  • infective: herpes zoster (Ramsay Hunt syndrome), EBV, CMV, HIV
  • inflammatory: sarcoidosis
  • autoimmune: rheumatoid arthritis
72
Q

Name 4 causes umn CN VII lesions

A
  • Cerebrovascular incident
  • intracranial tumour
  • multiple sclerosis
  • HIV