Cranial nerve examination (Dr Ummu and Telly O Connor)
Olfactory nerve, 1st cranial nerve (sensory)
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External appearance of nose: rash and deformity
Anosmia (loss of smell): frontal or temporal lobe lesion
o Test each nostril with coffee or alcohol swab
o Avoid use any pungent substances because it will irritate the patient
o Causes of anosmia
▪ URTI (Commonest)
▪ Smoking and increase in age
▪ Ethmoid Ca.
▪ Basal skull fracture
▪ Frontal fracture
Hyperosmia (increase in sensitivity sense of smell)
o Sign of psychosis, migraine, hysteria and encephalitis
Parosmia (perversion of smell)
o Due to head trauma and psychosis
Optic nerve, 2nd cranial nerve (sensory)
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Visual acuity
o Snellen chart by wearing glasses if they have and close one eyes with palm of hand
and each eye tested separately. To make thing fast, ask patient to read smallest line
possible
o Normal visual acuity is when line marked 6 can be read correctly with each eye
o Causes of bilateral blindness
▪ Bilateral occipital lobe infarct
▪ Bilateral occipital lobe trauma
▪ Bilateral optic nerve damages
▪ Hysteria
o Sudden blindness in one eye (MONA)
▪ Retinal artery or vein occlusion
▪ Temporal arteritis (appearance of prominent and tender artery)
▪ Optic neuritis
▪ Migraine
o Bilateral blindness of gradual onset cgdncd
▪ Cataracts
▪ Acute glaucoma
▪ Macular degeneration
▪ Bilateral optic nerve damage
▪ Diabetic neuropathy
▪ Bilateral optic nerve or chiasmal compression
Visual field
o Use your fingers to perform a quick screening test of the visual fields.
o Usually you hold up two fingers and bring them into the centre of vision in the four
quadrants.
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Wiggle your fingers and ask the patient to say ‘yes’ when movement of the fingers is
first seen.
Fundoscopy
Ocular nerves 3rd, 4th and 5th cranial nerve (motor)
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Assess pupil and movement of eyes
o Ptosis of eyelids
o Pupils (look at an object with distance then examine:
▪ Size
▪ Shape
▪ Equality
▪ Regularity
o Light reflex
▪ Direct response
▪ Consensual response
o Accommodation
▪ Look at object with near and far distance
o Eye movement (LR6SO4)
▪ Lateral Rectus (6th nerve) move eyes horizontally outwards
▪ Medial Rectus (3rd nerve) move eyes horizontally inwards
▪ Eye abducted:
• The elevator is superior rectus (3rd nerve)
• Depressor is inferior rectus (3rd nerve)
▪ Eye adducted:
• Elevator is inferior oblique (3rd nerve)
• Depressor is superior oblique (4th nerve)
Trigeminal nerve, 5th cranial nerve
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Facial sensation
o Pain and sharp sensation
▪ Test sharp end and ask patient to close eyes
▪ Apply the pin and ask patient either sharp or dull
▪ Loss of pain sensation will result pin prick feeling dull
o Light touch sensation
▪ Use cotton wool and instruct patient to say yes, each time touch of cotton
wool is felt
Examine motor
o Ask patient to clench teeth and palpate contraction of muscle:
▪ Masseter muscle above mandible
Jaw reflex
o Ask patient to let mouth fall open slightly
o Place finger on tip of jaw and tap it lightly with tendon hammer
Facial nerve, 7th cranial nerve
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Facial asymmetry
Muscle power
o Ask patient to look up so as wrinkle of forehead
o Ask patient to close eyes tightly and try to force open each eye
o Ask patient to puff their cheek
o Ask patient to smile and show their teeth
Acoustic nerve, 8th cranial nerve
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If patient wearing hearing aid, remove it for a while
Inspect the ears for any scars and deformity
Test the hearing with testing one ear while another ear covered by finger
Whisper a number and ask patient to repeat the number
If partial deafness is suspected, perform weber test first then Rinne’s test using 512 Hz fork
Glossopharyngeal, 9th cranial nerve and vagus nerve, 10th cranial nerve
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Ask patient to open the mouth and inspect the uvula by asking patient saying “Ahhhhhhh!”
Gag reflex (not necessary)
Ask patient to speak to access hoarseness of voice
Accessory nerve, 11th cranial nerve
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Ask patient to shrug shoulder and feel the bulk of trapezius muscle and attempt to push the
shoulder down and ask patient to resist the push
To test right sternocleidomastoid muscle: Ask patient to turn the head to the left, and ask
patient to turn head straight (midline) against resistant of your left hand. Then for left
sternocleidomastoid muscle, use your right hand
Hypoglossal nerve, 12th cranial nerve
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Inspect tongue on floor of the mouth for any wasting and fasciculation (fine, irregular, nonrhythmical muscle fibre contraction) as sign of lower motor neuron lesion
Ask patient to protrude his tongue and look for any deviation to weaker side