9 - Cranial Nerves I - VI Flashcards

1
Q

What do the cranial nerves supply in general?

A
  • Part of the PNS and supply structures of the head and neck, apart from the vagus nerve which supplies structures in thorax and abdomen
  • 12 pairs
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2
Q

Where are the majority of cranial nerve nuclei found?

A

BRAINSTEM - which is the area of cardiorespiratory control and consciousness

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3
Q

How can you remember all of the names of the cranial nerves?

A

Function:

Some Say Marry Money But My Brother Says Big Brains Matter More

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4
Q

Which of the following cranial nerves are:

  • Purely sensory?
  • Carry autonomics?
A

- Sensory (all special sensory): Vestibulocochlear (VIII), Optic (II), Olfactory (I) [1,2,7]

- Efferent autonomics: Oculomotor (III), Facial (VII), Glossopharyngeal (IX), Vagus (X) [3.7.9.10]

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5
Q

What is the function, path and origin of CNI?

A

SMELL

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6
Q

How would you test cranial nerve I and what would cause this nerve to be damaged?

A

OLFACTORY

Test: not often but sense of smell one nostril at a time

Anosmia: common cold due to swollen nasal cavity, head injury (shearing or basilar fracture), tumours as base of frontal lobe

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7
Q

What is the function, path and origin of CNII?

A

OPTIC

  • After the optic chiasm the fibres from both eyes start to mix and go down the optic tract
  • Travels back to occipital lobe to get to primary visual cortex to be percieved
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8
Q

What makes the first two cranial nerves, olfactory and optic, different from the other ten?

A

They are paired anterior extensions of the forebrain, not originating from the brain stem

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9
Q

How would you test CNII?

A
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10
Q

Why do you get photophobia in meningitis?

A

The optic nerve carries an extension of the meninges so this is irritated so when stimulating this nerve it causes pain

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11
Q

What are some ways the optic nerve can be damaged?

A
  • Different lesions lead to different visual pathway issues, e.g one eye affected if retina or optic nerve affect
  • Retinal detachment, optic neuritis, stroke
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12
Q

How would a pituitary tumour affect the optic nerve?

A

Would compress optic chiasm and cause bitemporal hemianopia

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13
Q

Although the optic nerve originates in the forebrain, what is it’s connection with the midbrain?

A

In the visual pathway

Communication of optic tract with brainstem

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14
Q

What is the function, path and origin of CNIII?

A

- OCULOMOTOR

  • Motor and Autonomic
  • Parasympathetic: sphincter and cilliary muscles
  • From midbrain
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15
Q

How would you test CNIII and how can this nerve be injured?

A
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16
Q

How is the oculomotor nerve damaged by a raised ICP?

A
  • Compressed between the tentorium cerebelli and uncus part of the temporal lobe as it herniates
  • Compresses the outside of the nerve which contains the parasympathetic fibres so leads to a blown pupil
17
Q

How can you remember which cranial nerves are to open and close the eyes?

A

- VII Fish Hook: closes by orbicularis oculi

- III Bars Holding Open: opens by levator palpebrae superior

Balance between the two to hold eyelid so if one goes the other wins

18
Q

A patient presents with this, what is the most likely lesion?

A
  • Ptosis and Down n Out

- Oculomotor (III) lesion

  • Appears pupil sparing so if no head injury may be a microvascular complication
19
Q

What is the function, path and origin of CNIV?

A
  • TROCHLEAR

- Motor

  • From DORSAL ASPECT of midbrain, one of the longest intracranial courses
20
Q

How would you test CNIV and how may this nerve be injured?

A
21
Q

What is the function, path and origin of CNV?

A

- TRIGEMINAL

  • From the pons
  • Sensory to face, teeth, sinuses
  • Motor to muscles of mastication
22
Q

What are the dermatomes of the face?

A
23
Q

How would you test CNV and what are some causes of damage to this nerve?

A

Corneal reflex is the blink reflex when the cornea is touched

24
Q

What is trigeminal neuralgia?

A
  • Sudden, severe facial pain.
  • Sharp shooting pain or like electric shock in the jaw, teeth or gums.
  • Short, unpredictable attacks that can last from a few seconds to about 2 minutes. The attacks stop as suddenly as they start.
  • Usually just one side of face, in lower part
  • Attacks can be triggered by certain actions e.g talking, smiling, brushing teeth, kissing
  • The compression of nerve is usually by nearby blood vessel, or can be due to MS or a tumour
25
Q

What is this and what is the major concern?

A
  • Opthalmic shingles
  • Vesicles can affect the front of the eye and can scar, which is vision threatening
26
Q

What is this and why is it painful?

A
  • Corneal ulcer
  • Innervated by sensory part of opthalmic nerve (Va)
27
Q

What are the important branches of the opthalmic nerve (Va)?

A

- Frontal: exits front of the orbit as supraorbital and supratrochlear to give sensory supply to forehead (trochlear), upper eyelid, conjuctiva and scalp (Conjunctiva upwards)

- Lacrimal: sensory to lacrimal gland, conjuctiva and upper eyelid

- Nasocilliary: sensory to sinuses, noses and eyes

ALL EXIT THROUGH SUPERIOR ORBITAL FISSURE

28
Q

What are the important branches of the maxillary nerve (Vb)?

A
29
Q

What are the important branches of the mandibular nerve (Vc)?

A

- Inferior alveolar: through bony canal and exits as mental nerve at mental foramen. Sensory to mental protuberance, lower lip and gum. Can be injured in mandible fracture

  • Lingual: general sensory from anterior tongue

- Auriculotemporal: general sensory from ear, temple, scalp and TMJ

30
Q

Label where the origin of each of the cranial nerves is?

A
31
Q

Which cranial nerves have a route through the cavernous sinus?

A

Not mandibular branch of trigeminal

32
Q

Where is the sensory for CN IX?

A

Baroreceptors in carotid sinus

33
Q

Which cranial nerves contain parasympathetics?

A

III, VII, IX, X

34
Q

Where is the pterygoid process?

A

Part of the sphenoid bone

35
Q

What foramina is the ICA linked with?

A

Comes in through carotid canal and runs over the foramen lacerum