Cranial Nerve Examination Flashcards
What should be completed in the introduction of the examination?
- Wash hands
- Introduction
- Identify patient
- Explain the exam
- Consent
- Confirm well-being
- Patient on chair at eye level
What should be noted on general inspection in a cranial nerve examination?
- Facial asymmetry
- Scars
- Ptosis
- Proptosis
- Speech abnormalities
- Eyelid & pupillary abnormalities
- Strabismus
- Arm & Leg Weakness
What is ptosis?
The drooping/falling of the upper eyelid
What is proptosis?
The protrusion of the eyeball
What is strabismus?
When the eyes don’t align properly when looking at an object
How is the Olfactory Nerve assessed (formally and informally)?
- Informal - ask if there is any change in their sense of smell
- Formal - using scratch and sniff cards, ask patient to close eyes & cover one nostril while other is tested
What is the name of the first cranial nerve?
Olfactory Nerve
What may be found in an abnormal olfactory nerve examination?
- Hyposmia
- Ansomnia
- Parosmia
- Phantosmia
What is hyposmia?
Reduced ability to smell
What is anosmia?
Inability to perceive odour
What may cause hyposmia & anosmia?
- Disease/damage to olfactory filaments due to trauma, compression or invasion by basal skull tumours
- Pre-symptomatic stages of Parkinson’s/Alzheimer’s
What is parosmia?
Pleasant smells are perceived as bad smells
What may cause parosmia?
- Head trauma
- Sinus infection
- Adverse drug reactions
What is phantosmia?
Olfactory hallucinations
What may cause phantosmia?
- Alzheimer’s disease
- Focal epilepsy
What 6 things are performed to inspect the optic nerve?
- Inspect the size, shape and symmetry of the pupils
- Use of the Snellen chart
- Test direct & consensual pupillary reflexes using a pen torch
- Visual inattention
- Visual fields
- Fundoscopy
What is the name of the second cranial nerve?
Optic nerve
What findings may there be when inspecting size, shape and symmetry of the pupils?
- Anisocoria
- Large & fixed pupils
- Small & reactive pupils
What is anisocoria?
- Pupil size asymmetry more than 0.4mm
- May be normal
What will the pupils look like in oculomotor nerve palsy?
Large & fixed
What will the pupils look like in Horner’s syndrome?
Small and reactive
What are the signs/symptoms of Horner’s syndrome?
- Ptosis
- Anhidrosis
- Miosis
- Inability to completely close or open the eyelid
- Facial flushing
- Headaches
What is ptosis?
Drooping of the upper eyelid
What is anhidrosis?
Decreased sweating
What is mitosis?
Constriction of the pupil
What is a Snellen chart used for?
To assess patient vision
What findings may be found on a Snellen chart?
- Decreased visual acuity
- If it improves by asking patient to read through a pinhole, there is a refractive element to poor vision
What are some causes to poor visual acuity?
- Refractive erros
- Amblyopia
- Cataracts/corneal scarring
- Macular degeneration
- Optic neuritis
- Lesions higher in the visual pathways
What is amblyopia?
A ‘lazy’ eye
How do you test direct and consensual pupillary reflexes using a pen torch?
- Bring the light source in from the side so that the patient doesn’t focus on it and accommodate
What is the direct pupillary reflex?
Shine a light into the pupil and observe constriction of that pupil
What is the consensual pupillary reflex?
Shine a light into the pupil and observe that pupil
What is the ‘normal’ result from a consensual pupillary reflex?
The eye without the light shone in should constrict
What is the swinging light test and how is it performed?
- Ensure the patient is looking forward at a select point
- Swing the light in front of the patient
What may a swinging light test reveal?
A relative afferent pupillary defect
What is a relative afferent pupillary defect?
When pupils respond differently to light stimuli shone in one eye at a time due to unilateral/asymmetrical disease of the optic nerve
How do you test visual inattention?
- Wiggle fingers from above and below & get patient to point at which one is moving
- Make sure patients are looking into your eyes
How do you test visual fields?
- Doctor and patient cover eyes opposite each other
- Move your finger in from the side
- Get the patient to tell you when it’s coming in to view
How are the oculomotor, trochlear & abducens nerves tested?
- Test the eye movements of the patient
- Tracing a H shape & central I shape, get them to follow with their eyes
- Perform a cover test
What is the name of the third cranial nerve?
Oculomotor nerve
What is the name of the fourth cranial nerve?
Trochlear nerve
What is the name of the sixth abducens nerve?
Abducens nerve
How do you perform the trace test for CN 3, 4 & 6?
- Hold your finger 30cm in front of the patient’s eyes and ask them to hold their head still
- Slowly trace a large H shape and a central I shape with your finger, taking the patient’s eyes to the limits of their gaze as you do so
What are the potential findings of the trace test for CN 3, 4 & 6?
- Diplopia
- Disconjugate eye movements
- Nystagmus
- Ptosis
- Restriction of eye movements
What is diplopia?
Double vision
What is nystagmus?
Involuntary eye movement
What may ptosis indicate?
An oculomotor lesion
How do you perform a cover test for CN 3, 4 & 6?
- Get a target to focus on, such as a pen top
- Cover one of the patient’s eyes and observe the uncovered eye for movement
- Repeat on the other eye
What may be the findings for a cover test for CN 3, 4 & 6?
- Convergent squint
- Divergent squint
What is a convergent squint?
When the eye moves temporally
What is a divergent squint?
When the eyes moves nasally
How would you test the trigeminal nerve?
- Demonstrate the tension of cotton wool with eyes open
- Get patient to close their eyes
- Place on forehead, cheek & jaw
What is the name of CN 5?
Trigeminal Nerve
Cotton wool isn’t felt on the forehead when testing for CN5. What branch is affected?
Ophthalmic branch
Cotton wool isn’t felt on the cheek when testing for CN5. What branch is affected?
Maxillary branch
Cotton wool isn’t felt on the jaw when testing for CN5. What branch is affected?
Mandibular branch
What should be noted when assessing CN5?
Whether there feels a difference between the sides of the body
How do you test the motor component of the trigeminal nerve?
Assess the temporals and masseter muscle
How do you assess the temporalis/masseter muscles?
- Get the patient to clench their teeth & palpate the temporalis simultaneously
- Get the patient to open their jaw and try and get them to resist you closing it
- Also perform a jaw jerk
How do you perform a jaw jerk?
- Relax jaw down slightly
- Place finger below lip
- Hit finger with hammer
- Sudden brisk closure = UMN lesion
How do you assess the facial nerve?
- Inspect the patient’s face for asymmetry, paying attention to the forehead wrinkles, nasolabial folds and the angles of the mouth
- Test the motor supply of the face
- Ask about changes to taste/hearing
What is the name of CN7?
Facial nerve
How is the motor supply of the facial nerve tested?
Ask the patients to copying you doing these actions:
- Raised eyebrows
- Close eyes
- Blow out cheeks
- Smile
- Purse lips
- Close lips
What symptoms may a patient have with changes to the facial nerve?
Changes to hearing or taste
How is the vestibulocochlear nerve tested?
- Ask about changes to the hearing
- Perform a gross hearing test
- Perform Rinne’s Test
- Perform Weber’s Test
- May perform Turning Test
What is the name of CN8?
Vestibulocochlear nerve
How is a gross hearing test performed?
- Assess the hearing by covering one ear, and whisper a number into another
- Repeat at arms length away
- Repeat on other side
How is Rinne’s test performed?
- Tap a tuning fork and place it on the base of the mastoid process
- If they can hear = get them to tell you when it has stopped
- Once the patient can no longer hear, move the tuning fork to approx 1 inch from the external auditory meatus
- Air conduction should be better than bone conduction
What is a Rinne’s positive finding?
The ability to hear the tuning fork via air conduction
What is neural deafness?
Both air and bone conduction are reduced equally
What is a Rinne’s negative finding?
Bone conduction is better than air conduction (conductive deafness)
How is a Weber’s Test performed?
- Place a tuning fork onto the forehead of the patient
- Tap the tuning fork and place it in the midline of the forehead
What are the two findings of Weber’s test?
- Conductive deafness = sound is heard louder on the side of the affected ear
- Neural deafness = sound is heard louder on the side of the intact ear
How is the Turning test performed?
- Stand patient up
- March on spot
- Pathology = patient turns towards lesion side
How are the glossopharyngeal & vagus nerves tested?
- Assess the soft palate and uvula
- Assess whether the uvula is in the midline at rest & note any deviation when saying ‘ah’
What is the name of CNIX?
Glossopharyngeal nerve
What is the name of CNX?
Vagus nerve
What findings may be found on assessment of glossopharyngeal/vagus nerves?
- Deviation of uvula = occurs away from the side of a glossopharyngeal nerve palsy
- Assess for a Bovine cough for vagus nerve palsy
What is a Bovine cough?
A non-explosive cough
What may a Bovine cough indicate?
A palsy in CNX
How is the accessory nerve tested?
- Test the trapezius muscle by asking the patient to shrug their shoulders against resistance
- Test the power in the sternocleidomastoids by asking the patient to turn their head against resistance
What is the name for CNXI?
Accessory Nerve
How is the hypoglossal nerve assessed?
- Inspect the tongue for wasting and fasciculations at rest
- Ask the patient to stick their tongue out to see if there is any deviation (towards lesion side)
- Place your hand on the cheek of the patient and get them to push their tongue against your hand - to see if there is weakness of the tongue
What are fasciculations?
A spontaneous, involuntary muscle twitch
What is the name of CNXII?
Hypoglossal nerve
What would be done to complete a cranial nerve examination?
- Full neurological examination of the upper and lower limbs
- CT/MRI head
