7 - Head & Neck - Cranial Nerves 2 Flashcards

1
Q

Name the lining of the cavernous sinus:

A

Dura mater

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2
Q

The cavernous sinus lies in which bone?

A

Sphenoid bone

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3
Q

Which artery passes through the cavernous sinus?

A

Internal Carotid Artery

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4
Q

Describe the location of the Optic Chiasm:

A

Directly ventral to the pituitary gland

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5
Q

Describe the route of CN I from the optic disc to the forebrain:

A
  • Enters skull from the retina via the Optic canal
  • Optic nerve runs from retina to optic chiasm
  • Crossover occurs at optic chiasm
  • Via optic tract to the Geniculate nuclei
  • From geniculate nuclei to visual cortex
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6
Q

What part of the optic pathway may be compressed by a pituitary tumour? How may this present?

A

Optic chiasm

Loss of acuity +/- vision

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7
Q

Name some toxins which can damage the optic nerve:

A
  • Ethambutol
  • Amiodarone
  • Methanol
  • Tobacco exposure
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8
Q

How is the optic nerve tested?

A

1) Acuity via Snellen chart
2) Colour via Ishihara plates
3) Fields
4) Pupillary light reflexes
5) Fundoscopy

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9
Q

How is the oculomotor nerve tested?

A
  • Inspect eyelid and pupils
  • Eye movements (H)
  • Pupillary light reflexes
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10
Q

How does an oculomotor lesion present?

A
  • ‘down-and-out’ eye
  • diplopia
  • loss of pupil constriction
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11
Q

List some common ways the oculomotor nerve is damaged:

A
  • Tumour/haemorrhage = increased intracranial pressure
  • Aneurysm
  • Cavernous sinus thrombosis
  • Diabetes
  • Hypertension
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12
Q

How is the trochlear nerve tested?

A
  • Eye movements (H)
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13
Q

How does a lesion of the trochlear nerve present?

A
  • Very subtle deviation of the eye, may compensate by tilting head
  • May have diplopia, worse on downward gaze
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14
Q

How is the trigeminal nerve tested?

A
  • Test muscles of mastication by asking to clench jaw
  • Corneal reflex (sensation to cornea)
  • Sensation to face
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15
Q

Which 2 cranial nerves does Shingle most commonly affect?

A

CN V Trigeminal

CN VII Facial

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16
Q

How is the abducens nerve tested?

A

Eye movements (H)

17
Q

How does a lesion to the abducens nerve present?

A

Diplopia

18
Q

Where does the facial nerve branch into 5?

A

Within the Parotid gland

19
Q

How is the facial nerve tested?

A

Test muscles of facial expression:

  • Close eyes against resistance
  • Raise eyebrows
  • Puff out cheeks
  • Reveal teeth
20
Q

What are the common causes of a facial palsy?

A
  • Middle ear tumour
  • Infection
  • Parotid tumour/infection
  • Shingles
  • Compression
21
Q

How is the vestibulocochlear nerve tested?

A
  • Hearing
  • Rinne’s test
  • Weber’s test
22
Q

Which cranial nerve(s) gives special sensory fibres for taste?

A
  • Anterior 2/3rds of the tongue = Facial nerve
  • Posterior 1/3rd = Glossopharyngeal nerve
  • Epiglottis and root of tongue = Vagus nerve
23
Q

How is the glossopharyngeal nerve tested?

A
  • Gag reflex
24
Q

Which cranial nerve gives special sensory fibres for taste to the epiglottis and root of tongue?

A

CN X Vagus

25
Q

How is the vagus nerve tested?

A
  • Check position of uvula
  • Speech
  • Swallow
  • Cough
  • Gag reflex
26
Q

Which cranial nerves contain the efferent and afferent limbs of the gag reflex?

A
Efferent = vagus nerve
Afferent = glossopharyngeal nerve
27
Q

The accessory nerve contains roots from which segments of the c-spine?

A

C1-5/6

28
Q

How is the accessory nerve tested?

A
  • Shrug shoulders against resistance

- Turn head against resistance

29
Q

If a vagus nerve is damaged, will the uvula deviate towards or away from the side of the lesion?

A

Away from the side of the lesion

30
Q

Where is the accessory nerve susceptible to injury?

A

Posterior triangle of neck

  • Lymph node biopsy
  • Stab wound etc
31
Q

Which cranial nerve crosses the internal and external carotid arteries in the neck?

A

CN XII Hypoglossal

32
Q

How is the hypoglossal nerve tested?

A
  • Inspection of tongue

- Movement of tongue

33
Q

If a hypoglossal nerve is damaged, will the tongue deviate towards or away from the side of the lesion?

A

Towards the side of the lesion

34
Q

What is an acoustic neuroma?

A

A benign tumour around CN VIII

35
Q

If the CN III nerve is damaged, why is the first symptom loss of pupillary constriction?

A

CN III autonomics ‘hitchhike’ on the outside of CN III, therefore first to be damaged.