Cranial Nerve Exam Flashcards
What is CN VIII (8)?
Vestibulocochlear nerve
What is CN IX (9)?
Glossopharyngeal Nerve
What is CN XI (11)?
Spinal accessory nerve
What is CN XII (12)?
Hypoglossal nerve
What is the pathology?
Bell’s Palsy (unilateral facial nerve weakness)
What is the pathology?
Stroke (UMN lesion affecting the facial muscles)
How can Bell’s be differentiated from a facial stroke?
Forehead sparing in stroke
Why is there forehead sparing in stroke?
Bilateral UMN supply to the superior part of the facial nerve nucleus
What is this sign?
Ptosis
What is this sign?
(Not the ptosis)
Miosis (pupil constricted)
What is this sign?
Mydriasis (pupil dilation)
How can you distinguish unilateral miosis from unilateral mydriasis?
The normal pupil should be more constricted in brighter light
What abnormality of speech is relevant to a cranial nerve exam?
Dysarthria (problems with articulation)
What are the aspects of a full optic nerve assessment?
(Doing all of these in an exam is excessive unless specifically asked to)
- Pupil inspection
- Visual acuity
- Pupillary reflexes
- Colour vision
- Visual fields
- Fundoscopy
What are the essential aspects of an optic nerve assessment?
- Pupil inspection
- Visual acuity (brief tests of ability to read/see)
- Visual fields
- Fundoscopy (may not be needed)
- Pupillary reflexes (also CN III)
What is the type of anisocoria and what is the likely cause?
Mydriasis - CN III lesion
What is the type of anisocoria and what is the likely cause?
Miosis - Horner’s syndrome
If performing fundoscopy as part of a cranial nerve exam, what aspects should be included?
- Red reflex
- Retinal visualisation
What is the name of and what can cause this sort of visual field defect?
- Monocular blindness
- Optic nerve or retinal lesion
What is the name of and what can cause this sort of visual field defect?
- Bitemporal hemianopia
- Lesion at the optic chiasm
What can cause a lesion at the optic chiasm?
Pituitary tumour
What is the name of and what can cause this sort of visual field defect?
- Right homonymous hemianopia
- Lesion of the optic tract
What is shown here?
Nystagmus
Palsy of which nerve is seen here?
Abducens
Palsy of which nerve is seen here?
Oculomotor nerve
Palsy of which nerve is seen here?
Trochlear nerve
What are the tests of pupillary reflexes?
- Accommodation reflex
- Direct pupillary reflex
- Consensual pupillary reflex
- Swinging light test
Which nerves are involved in the light reflexes?
2 and 3
If there is absence of direct reflex but presence of consensual, which nerve is affected?
2
If there is absence of direct and consensual reflexes in one eye, which nerve is affected?
3
If there is loss of consensual reflex only which nerve is affected?
The contralateral 2nd nerve
How can the vestibulocochlear nerve be tested?
- Whisper a number in the paitent’s ear and ask them to repeat it
- Weber’s test
- Rinne’s test
What is Weber’s test?
- Place a tuning fork on the patient’s forehead
- Ask them which ear it localises to if any
What does localisation of Weber’s test suggest?
Asymmetrical hearing loss
Where does the sound localise to in an asymmetrical sensorineural hearing loss in Weber’s test?
The unaffected ear
Where does the sound localise to in an asymmetrical conductive hearing loss in Weber’s test?
Affected ear
What is Rinne’s test?
- Place the tuning fork on the mastoid process and ask them to tell you when it stops
- Move fork to in front of ear and ask if they can still hear it
What result of Rinne’s suggests conductive hearing loss?
Unable to hear once moved from mastoid
What suggests sensorineural loss in Rinne’s test?
Able to hear sound when moved from mastoid process (in the ear that sound localised away from in Weber’s test - will show the same Rinne result in normal ear)
What are the Bulbar cranial nerves?
9, 10, 12
How should the bulbar nerves be tested?
- Cough
- Articulation
- Examine pharynx
- Tongue movements
What cranial nerve is tested by asking the patient to cough?
10 (vagus)
What nerves are involved in articulation?
- (7)
- 10
- 12
How is the pharynx examined?
- Use a tongue depressor and pen torch
- Ask the patient to say ahh and observe uvula
- Remove tongue depressor
- Ask to swallow
Where does the uvula deviate in a CN IX or X lesion?
Away from the lesion on saying ahh
What is not normally tested in a conscious patient?
Gag reflex
How is CN 12 tested?
- Ask the patient to stick their tongue out
- Observe for wasting
- Move side to side
- Push tongue into side of cheek and apply resistance
What indicates a CN 12 lesion?
Deviation towards the lesion
Which muscle provides shoulder shrugging?
Trapezius
What additional tests can be considered after a cranial nerve exam?
- Neuro exam of the limbs
- Gait and balance
- CT/MRI head
What is shown here?
Left CN XII lesion
What is shown here?
Left CN IX or X lesion
