Cranial Nerves Flashcards
Olfactory nerve function
Smell
Unilateral anosmia
Subfrontal tumour
Bilateral anosmia
Mucous blockage Head trauma Congenital Parkinson’s Covid 19
Optic Nerve mnemonic
I-AFRO Inspect Acuity Fields Reflexes Ophthalmoscope
Miosis
Pupillary constriction
Mydriasis
Pupillary dilation
Aniscoria
Asymmetry in pupil size
Snellen chart numbers
Top number equates to distance in metres (should be 6)
Bottom number identifies the position on the chart of the smallest line read by the patient
What does bottom number on snellen chart equate to
The distance at which a normal person could read this line in metres
Snellen chart- if patient can read a line minus two letters/makes two mistakes
Can be recorded as e.g. 6/6 (-2)
Snellen chart- if person makes more than 2 mistakes
The previous line should be recorded as their acuity
If patient unable to read top of snellen chart from 6 metres
Reduce distance to 3m
Reduce distance to 1m
Assess if they can count number of fingers you’re holding up
Assess if they can see gross hand movements
Assess if they can detect light from pen torch
No perception of light
Extra things for visual acuity
Assess near vision by asking patient to read a paragraph in fine print (Jaeger eye chart)
Colour vision with Ischihara plates
Causes of decreased visual acuity
Optic nerve pathology (e.g. optic neuritis) Refractive errors Amblyopia Cataract Corneal scarring Age-related macular degeneration
If poor distance visual acuity, can repeat test through a
Pinhole
suggests refractive component to poor vision
Visual inattention during visual fields
Parietal lobe lesion
Three reflexes
Direct + consensual pupillary reflexes
Swinging light test
Accomodation reflex
Swinging light test
Move torch rapidly between two pupils
Assessing for paradoxical dilation of a pupil with a RAPD (marcus-gunn pupil)
Nystagmus
Cerebellar lesion
Inspection for CN III, VI and IV
Strabismus (squint)
Ptosis
What do u test for Trigeminal
Sensory V1-3
Motor- muscles of mastication
Reflexes
Trigeminal- motor testing
Temporalis
Masseter
Lateral pterygoids- open mouth whilst apply resistance
Lateral pterygoid issue
Deviation towards sign of lesion
Jaw jerk reflex
Brisk upwards movement of the jaw and mouth closing completely- UMN
Corneal reflex
Absence means either trigeminal or facial nerve palsy
Efferent- trigeminal
Afferent- facial
Facial nerve testing
Special sensory (taste) Motor- facial muscles
Weber’s test- Sensorineural deafness
Lateralises to (heard louder in) unaffected ear
Weber’s test- conductive deafness
Lateralises to affected ear
Rinne’s test- sensorineural deafness
AC>BC (rinne’s positive)
Rinne’s test- conductive deafness
BC>AC (rinne’s negative)
Vestibular testing
Turning test
Vestibular lesion- patient will turn towards side of lesion
Uvula
Deviates away from lesion
Gag reflex
Afferent= glosso Efferent= vagus
Tongue
Deviates towards side of lesion
Further tests
Full neurological of upper and lower limbs
Cerebellar
Formal hearing assessment
Neuroimaging
