Cranial nerve examination Flashcards
CN-1
Olfactory, sensory
Any change in sense of smell
CN-2
Optic - sensory
Visual acuity
CN-3
Occulomotor - motor
EOM except superior oblique and lateral rectus
Pupillary constriction
CN-4
Trochlear - motor
Superior oblique
CN-5
Trigeminal - mixed
Sensation to face
Muscles of mastication
Jaw-jerk and corneal reflex
CN-6
Abducens - motor
Lateral rectus
CN-7
Facial nerve - mixed
Muscles of facial expression, stapedius muscle
Taste - anterior two-thirds of tongue
CN-8
Vestibulocochlear - sensory
Balance and hearing
CN-9
Glossopharyngeal - mixed
Sensation to pharynx, posterior third of tongue
Motor to stylopharyngeus
CN-10
Vagus - mixed
sensation to pharynx and larynx
Muscles of pharynx, larynx and palate
CN-11
Accessory - motor
Trapezius, SCM
CN-12
Hypoglossal - motor
Muscles of the tongue
Corneal reflex
Afferent - CN5
Efferent - CN7
Jaw-jerk reflex
Afferent - CN5
Efferent - CN5
gag reflex
Afferent - CN9 (glossopharyngeal)
Efferent - CN10 (vagus)(
Eye exam process
Visual acuity
Visual fields
Fundoscopy
Pupils - size, reactivity (direct and consensual), RAPD
Movements
Accommodation
Causes of RAPD
Optic nerve disease:
Demyelination - Multiple sclerosis, Neuromyelitis optica spectrum disorder, anti-MOG
Ischaemia - including GCA
Compression - orbital tumours, thyroid eye disease
Other optic nerve inflammation: sarcoidosis, SLE, sjogrens
Eye disease:
Retina - ischaemia (retinal artery or vein), retinal detachment,
Other - intra-occular tumour, glaucoma
Causes of absent light reflex with preserved accommodation reflex
Midbrain lesion - Argyll Robertson pupil of syphilis
Ciliary ganglion lesion - Adie’s pupil
Types of eye movements
Pursuit - following a moving object (cerebellum and brainstem)
Saccadic - rapid movement to fix on an object (frontal lobe, brainstem, cerebellum)
Convergence - midbrain
Vestibulo-occular reflex - compensate for movements of the head to remain fixed on a target (vestibular organs, cerebellar and vestibular nuclei)
Six eye muscles
Superior rectus
Lateral rectus
Inferior rectus
Superior oblique
Medial rectus
Inferior oblique
Features of third nerve palsy
complete or partial ptosis
down and out eye
dilated pupil, unreactive to direct light and accommodation
causes of third nerve palsy
Central causes: brainstem lesions (tumours, demyelination, vascular)
Peripheral causes: compressive lesions (aneurysm, usually posterior communicating artery), tumour, basal meningitis, nasopharyngeal carcinoma, orbital lesions. Ischaemia or infarction, migraine
features of fourth nerve lesion
paralysis of the superior oblique muscle (causes weakness of downward movement)
causes of fourth nerve lesion
idiopathic or trauma
Features of sixth nerve lesion
failure to abduct eye
causes of sixth nerve lesion
bilateral lesions - wernicke’s encephalopathy, mononeuritis multiplex, raised intracranial pressure
unilateral lesions - idiopathic, trauma related, vascular lesion, raised intracranial pressure, diabetes
What distinguishes supranuclear palsy from cranial nerve lesions
- both eyes affected
- pupils may be fixed
- Usually no diplopia
- reflex eye movements are usually intact (flexing / extending the neck)
PSP eye findings
loss of vertical gaze then later horizontal gaze
associated with extrapyramidal signs, neck rigidity, dementia
Localising lesions - unilateral 3, 4, V1 and 6 nerves
cavernous sinus involvement
Localising lesions - unilateral 5, 7 and 8 lesions
cerebellopontine angle lesion
Localising lesions - unilateral 9, 10 and 11
Jugular foramen lesion
Localising lesions - bilateral 10, 11, 12
Bulbar palsy - if lower motor neurone changes are present
Pseudobulbar palsy - if upper motor neurone signs present
