Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

AHNNS > 7. Cranial Nerves I-VII > Flashcards

7. Cranial Nerves I-VII Flashcards

1
Q

What is the location of the majority of the cranial nerve nuclei?

A

Brainstem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the role of the brainstem?

A

Regulation of cardio-respiratory functions and maintaining consciousness.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How many cranial nerves arise from the brain (forebrain), midbrain, pons and medulla?

A

Brain (forebrain) - 2.
Midbrain - 2.
Pons - 4.
Medulla - 4.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What cranial nerves arise from the forebrain?

A

I - olfactory nerve.

II - optic nerve.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the function of CN I, the olfactory nerve?

A

Special sensory - olfaction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Through which foramen does CN I, the olfactory nerve pass?

A

Cribiform foramina.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Damage to the CN I, the olfactory nerve, can cause anosmia. What injuries can cause this?

A

Head injury causing anosmia secondary to shearing forces and/or a basilar skull fracture damaging the olfactory nerve.
Intracranial tumours at base of frontal lobes within the anterior cranial fossa.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the most common cause of anosmia?

A

Common cold.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How would you test clinically for damage to CN I, the olfactory nerve?

A

Ask if patient has noticed any difficulties or changes in sense of smell.
Test one nostril at a time with smelling salts, coffee, peppermint etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the function of CN II, the optic nerve?

A

Special sensory - vision.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Through which foramen does CN II, the optic nerve, pass?

A

Optic canal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why can the optic nerve swell due to raised intracranial pressure?

A

Carries an extension of the meninges.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What would you see as evidence of raised intracranial pressure on a fundoscopy?

A

Swollen optic disc (papillodema).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why do lesions involving the retina or the optic nerve cause visual disturbances affecting only one eye?

A

Lesion occurring before the optic chiasm, so there is no mixing of optic nerve fibres.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What can the optic nerve be seen directly with?

A

An ophthalmoscope.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How would you test for damage to CN II, the optic nerve?

A

Test one eye at a time.

Do both visual tests and test the pupil responses/reflexes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What can cause bilateral visual symptoms (bitemporal hemianopia) and why?

A

Pituitary tumours, as compressive optic chiasm.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the purpose of there being some communication from the optic tracts with the brainstem?

A

To allow for certain visual reflexes eg pupillary reflexes to light.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What two cranial nerves arise from the midbrain?

A

CN III - oculomotor.

CN IV - trochlear.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the function of CN III, the oculomotor nerve?

A

Motor - supplies most extra-ocular muscles and levator palpebrae superioris (opens eyelid).
Autonomic (parasympathetic) - ciliary muscle (lense) and sphincter pupillae (pupil).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Through which foramen does CN III, the oculomotor nerve pass?

A

Superior orbital fissure.

22
Q

Why can raised intracranial pressure lead to compression of CN III, the oculomotor nerve, causing an enlarged pupil on the affected side?

A

Oculomotor nerve runs very close to the tentorium cerebelli, so raised intracranial pressure pushes the uncus onto the oculomotor nerve.

23
Q

Where do the autonomic and motor fibres sit in CN III, the oculomotor nerve?

A

Autonomic (parasympathetic) found at the edge of the nerve, motor fibres in the centre.

24
Q

What is seen clinically in compression of CN III, the oculomotor nerve?

A

Pupillary dilation and/or diplopia.

‘Down and out’ position with sever ptosis (eyelid droop).

25
Q

What can cause compression of CN III, the oculomotor nerve?

A

Raised intracranial pressure (due to tumour or haemorrhage).
Aneurysms of the posterior communicating artery.
Vascular secondary to diabetes of hypertension (typically pupil sparring).
Cavernous sinus thrombosis.

26
Q

How would you test for damage to CN III, the oculomotor nerve?

A

Inspection of eyelid and pupils.
Test eye movements.
Test pupillary light reflexes.

27
Q

What is the function of CN IV, the trochlear nerve?

A

Motor - innervates 1 extra-orbital muscle the superior oblique.

28
Q

Through which foramen does CN IV, the trochlear nerve pass?

A

Superior orbital fissure.

29
Q

What cranial nerve is the only nerve to emerge from the dorsal aspect of the brain, giving it the longest intracranial course of any of the cranial nerves?

A

CN IV, the trochlear nerve.

30
Q

What can be seen clinically when there is damage to CN IV, the trochlear nerve?

A

Diplopia which is worse on downward gaze, and can be corrected with tilt of the head.

31
Q

What injuries and conditions can cause damage to CN IV, the trochlear nerve?

A

Head injury.
Any cause of raised intracranial pressure.
Congenital palsies.

32
Q

How would you test for damage to CN IV, the trochlear nerve?

A

Test eye movements.

33
Q

What intracranial nerves arise from the pons?

A

V - trigeminal.
VI - abducens.
VII - facial.
VIII - vestibulocochlear.

34
Q

What is the function of CN V, the trigeminal nerve?

A

S - main sensory nerve of the face.

M - supplies muscles of mastication.

35
Q

What are the 3 branches of the trigeminal nerve and what foramen does each pass through?

A

Opthalmic nerve - superior orbital fissure.
Maxillary nerve - foramen rotundum.
Mandibular nerve - foramen ovale.

36
Q

What may be seen clinically due to injury of CN V, the trigeminal nerve?

A

Loss of sensation in dermatomes Va, Vb or Vc.

Lack of corneal reflex as forms afferent limb of corneal reflex.

37
Q

What injuries and conditions can lead to damage of CN V, the trigeminal nerve?

A

Orbital/facial trauma damaging cutaneous branches.
Trigeminal neuralgia.
Shingles.

38
Q

How would you test for damage to CN V, the trigeminal nerve?

A

For sensation test dermatomal areas CN Va, Vb and Vc.
Muscles of mastication.
Corneal reflex.

39
Q

Where does the maxillary nerve branch of CN V, the facial nerve, run through before exiting the skull for the second time and what as?

A

Runs through base of orbit, exits as infraorbital nerve.

40
Q

Why can a blow out fracture lead to reduced sensation to the cheek underneath the orbit?

A

Damaged infraorbital nerve.

41
Q

What 3 branches does the mandibular nerve of Cn V, the trigeminal nerve, give rise to, and what does each innervate?

A

Interior alveolar nerve - gum.
Mental nerve - lip.
Lingual nerve - tongue.

42
Q

Why does a fracture to the mandible lead to reduced chin sensation?

A

The inferior leveller nerve runs through the mandibular foramen, and emerges as the mental nerve through the mental foramen. So a fracture severed the nerve leading to loss of sensation.

43
Q

What is the function of CN VI, the abducens nerve?

A

Motor - innervates the lateral rectus for lateral abduction of the eye.

44
Q

Through which foramen does CN VI, the abducens nerve pass?

A

Superior orbital fissure.

45
Q

What type of injury can cause damage to CN VI, the abducens nerve? Why?

A

Injury eg bleed, tumour leading to raised intracranial pressure.
Nerve emerges anteriorly at the ponto-medullary junction before running under the surface of the pons upwards towards the cavernous sinus, so can be easily stretched in raised intracranial pressure.

46
Q

What do patients present with when there is damage to CN VI, the abducens nerve?

A

Diplopia.

47
Q

What is the function of CN VII, the facial nerve?

A

Motor - innervates muscles of facial expression.
Special sensory - taste at anterior 2/3 tongue.
Autonomic (parasympathetic) - to lacrimal gland and salivary gland.

48
Q

Through which foramen does CN VII, the facial nerve pass through?

A

The internal auditory meatus, then through the petrous part of the temporal bone.

49
Q

How many branches does CN VII, the facial nerve, give off?

A

5 extracranial and 2 intracranial (within petrous).

50
Q

What structures does CN VII, the facial nerve, have a close relationship with?

A

Vestibulocochlear nerve.
Middle ear.
Parotid gland.

51
Q

What can cause damage to CN VII, the facial nerve?

A

Idiopathic facial nerve palsy eg Bell’s palsy.

52
Q

How would you test for damage to CN VII, the facial nerve?

A

Test muscles of facial expression.
Test corneal reflex (efferent limb).
Test taste on anterior 2/3 of tongue.

AHNNS (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions