Neuro - CN Flashcards
Name the cranial nerves (CN I - XII)
- I olfactory
- II optic
- III oculomotor
- IV trochlear
- V trigeminal
- VI abducens
- VII facial
- VIII vestibulocochlear
- IX glossopharyngeal
- X vagus
- XI accessory
- XII hypoglossal
Which are the visual cranial nerves?
- II optic
- III oculomotor
- IV trochlear
- VI abducens
Which are the bulbar cranial nerves?
- IX glossopharngeal
- X vagus
- XII hypoglossal
What is the exposure requried for a cranial nerve exam?
clavicle up
what might be observed on general inspection during a cranial nerve exam?
- unilateral neck muscle wasting neck (XI)
- facial droop/asymmetry (VII)
- articulation of words (V, VII, X, XII)
- ptosis (III)
- strabismus e.g. ambylopia (III, IV, VI)
- abnormal/asymmetric pupils (II, III)
How do you test CN II?
Inspection, AFRO
-
Acuity
- distant vision - Snellen test
- near vision
- colour vision - Ishihara plates
-
Fields
- inattention
- fields
- blind spots
-
Reflexes
- accommodation
- direct & consensual
- swinging light - normal reaction = slight constriction, then slight dilation
-
Ophthalmoscopy
- ‘to visualise optic disc’
a) What is Horner’s syndrome?
b) What are the signs of Horner’s syndrome?
a) range of symptoms when sympathetic trunk is damaged
b) ipsilateral: miosis, partial ptosis, anhydrosis, enophthalmus
How do you test CN I?
‘have you noticed any changes in your sense of smell?’
offer to test with UPen smell identification test
How do you test CN III, VI, VI?
CN III = optic ; CN IV = trochlear ; CN VI = abducens
Inspect
- H Test
- saccades test
- convergence test (bring finger towards nose, pupil shrinks)
What is the pathology if there is
a) partial ptosis
b) complete ptosis
a) Horner’s syndrome
b) CN III lesion
What are the afferent and efferent nerves for the accommodation reflex?
afferent = CN II
efferent = CN III
What are the afferent and efferent nerves for the
a) direct pupillary reflex
b) consensual pupillary reflex
a) afferent = CN II ipsilateral ; efferent = CN III ipsilateral
b) afferent = CN II contralateral ; efferent = CN III ipsilateral
What are the afferent and efferent nerves for the swinging light reflex?
????
- What is a Marcus-Gunn pupil?
- What does a Marcus-Gunn pupil suggest?
1) when pupils dilate (to some degree) when a bright light is swung from the unaffected eye to the affected eye;
* as opposed to normal reaction = slight constriction, then slight dilation*
2) optic nerve lesion e.g. due to glaucoma, MS
How do you test CN V?
inspect (wasting: masseter, temporalis, lateral pterygoids)
-
sensory:
- ‘any areas of pins and needles or numbness?’
- sharp & dull sensation testing over 3 branches (temporal, maxillary and mandibular) ‘does it feel the same on both sides?’
-
motor
- from behind: clench jaw, feel masseters, temporalis & lateral pterygoids
-
reflexes:
- offer: corneal reflex
- offer: jaw jerk reflex
When testing CN V, what would you do if there are any sensory abnormalities found?
test the 3 branches again for:
- temp sensation: cold tuning fork
- light touch sensation: cotton wool
What are the afferent and efferent nerves for the corneal reflex?
afferent = CN V: nasociliary branch of ophthalmic division
efferent = CN VII
How do you test CN VII?
inspect
Motor:
- Raise eyebrows
- Scrunch up eyes + try to prise each open in turn with your thumbs
- Purse lips together + try to prise each open in turn with your thumbs
- Show teeth
- Puff out cheeks + try to push air out
How does
a) UMN present when raising eyebrows (CN VII)?
b) LMN present when raising eyebrows (CN VII)?
a) forehead spared, bilateral eyebrow raise
b) unilateral eyebrow raise
How do you test CN VIII?
‘any changes in hearing?’
- Crude hearing test: rub fingers in one ear
-
Weber test -
- 512Hz
- forehead ‘which side is louder?’
-
Rinnes test -
- 512Hz
- mastoid process ‘tell me when it stops’
- by ear ‘can you hear it again?’
offer: vertigo tests e.g. Dill-Hallpike test
What would be the results of Weber & Rinne’s in
a) sensorineural hearing loss
b) conductive hearing loss
How do you test CN IX & X?
-
Inspect: open mouth say, ahhh
- look for palate symmetry (CN IX)
- look for uvula deviation (CN X)
-
Motor:
- speech - ‘say ahh & British constitution’
- cough
- swallow
-
Reflex:
- offer: gag reflex
How do you test CN XI?
Inspect: SCM, trapezius wasting
Motor: against resistance - turn head & shrug shoulders
How do you test CN XII?
‘have you noticed any changes/slurring in your speech?’
Inspect
- tongue wasting or fasciculations
Motor
- stick out tongue - deviation?
- against resist. press tongue inside cheek
CHow could you complete your cranial nerve examination?
- Full Hx
- Upper & lower limb neuro examination
- fundoscopy (if hearing impaired)
- nerve conduction study
- CT head
What is
a) bulbar palsy
b) pseudobulbar palsy
a) LMN lesion
b) UMN lesion
How could you differentiate between bulbar palsy and pseudobulbar palsy?
