Cranial Nerve exam Flashcards
Introduction:
Go through the introduction of Cranial nerve examination
WIPE
- Wash hands
- Introduce self
- Ask Patient’s name, DOB and what they like to be called
- Explain examination and obtain consent
- General Inspection
Go through General inspection of cranial erve exam
Look at the patient in general from the end of the bed
* Posture
* Habitus
* Other signs of neurological conditions
And look around the bed for signs such as:
* Mobility aids
* NBM signs
* Fluid thickener
* Glasses
* Hearing aids
- How is CN I tested?
CN I: Optic nerve
* Changes in smell? Unilateral/bilateral
* Test each nostril with smelling salts/strong smelling substance
- How is CN II tested?
- Visual acuity
- Pupillary responses
- Visual fields
- Visual inattention
- Accommodation
- Fundoscopy
How is visual acuity tested?
- Crude: asking is pateint can see equally well from both eyes
- Snellen’s chart:
- Distant visionone eye at a time. Read down the line until pt gets > 2 letters wrong, previous line recorded as acuity
- Near vision: read a line of magazine/letter
- Colour vision: Ishihara plates
How is pupillary response tested?
- Inspect size/shape of pupil/ symmetry?
- Pt fixes gaze on distant point in dark room, light shone on each pupil
- Ipsilateral: direct response
- Contralateral: indirect repsonse
What is the afferent and efferent barnch of the pupuillary response?
- Afferent: CN II
- Efferent: CN III
How are visual fields tested?
Confrontation (compares the patient’s visual fields to your own)
* Sit at same level as patient (1m apart) Ask patient to cover
one eye and to look at your nose. You cover your opposite eye
(i.e. your left and patient’s right)
* Bring your finger from the furthest periphery towards the central vision and ask the patient to say ‘yes’ when they can see your finger moving. Test each quadrant in turn
* Positioning your hand equi-distant between you and the patient will allow you to compare your visual field with
that of the patient. Repeat for the other eye.
What are visual field defects a sign of?
- Cranial nerve problem: bitemporal hemianopia
- Hemisphere problem: homonomous hemianopia
What are visual field defects a sign of?
- Cranial nerve problem
- Hemisphere problem
What is monocular vsiual loss a sign of?
How is accomodation tested?
Ask the patient to focus on a distant object, then hold your finger close to their face and ask them to focus on it. Pupils should constrict and eyes should converge
How are CN III, CN IV and CN VI tested?
Eye movements
* Inspect eyes: pupilabnormality/ptosis/abnormal gaze
* Ask pateint to follow finger in slow H pattern. Ask if theres any double vision. Nyastagmus?
What does CN III innervate (motor)?
- Superior, medial and inferior rectus muscles
- Inferior oblique
- Levator palpebrae superioris
What does CN III innervate (parasympathetic)?
Constrictor pupillae
Cillairy msucles (accommodation)