Disorders of Special Sensory Function: The Cranial Nerves Flashcards
Hehe lets recap-
CN I?
Olfactory
CN II?
Optic
CN III?
Oculomotor
CN IV?
Trochlear
CN V?
Trigeminal
CN VI?
Abducens
CN VII?
Facial
CN VIII?
Vestibulocochlear
CN IX?
Glossopharyngeal
CN X?
Vagus
CN XI?
Accessory
CN XII?
Hypoglossal
Name the special senses.
Olfaction
Vision
Taste
Hearing
Which cranial nerve has a role in olfaction?
CN I
Which cranial nerve has a role in vision?
CN II
Which cranial nerves have a role in taste?
CN VII, IX, X
Which cranial nerve has a role in hearing?
VIII
Which cranial nerve has a role in balance?
CN VIII
Which nerve mainly supplies ordinary sensation to the face?
Trigeminal nerve
Which nerves supplies the ear with ordinary sensation?
Facial nerve
Glossopharyngeal nerve
Which nerve controls the majority of the eye muscles?
Oculomotor nerve- CN III
Which nerves supplies the superior oblique muscle?
Abducent nerve- CN IV
Which nerve supplies the lateral rectus muscle?
Trochlear nerve- CN VI
Which cranial nerve supplies the muscles of mastrication?
Trigeminal nerve
Which nerve supplies the muscles of facial expression?
Facial nerve- CN VII
Which nerve supplies the muscles of the larynx and pharynx?
Mainly vagus nerve- CN X
Which nerve supplies the sternomastoid and trapezius muscles?
Accessory nerve- CN XI
Are all autonomic functions sympathetic or parasympathetic?
Parasympathetic
Which nerve causes pupillary restriction?
Oculomotor nerve
Which nerves cause salivation?
Submandibular and sublingual glands innervated by facial nerve
How do you test smell (olfactory nerve III)
-Unilaterally or bilaterally
-Usually history based
-Can use a smell test but rare
List the different areas that are tested when testing the optic nerve.
Visual acuity
Visual field
Pupillary reactions
Fundoscopy
Colour vision
What is used to test visual acuity?
Snellen chart
Which chart is used to assess colour vision?
Ishiara plate
When looking at a patient’s eye, what would be looked for?
-Ptosis- dropping of eyelid
-Equal pupil size
-Pupillary reactions
-Eye movements, both vertical and horizontal
When testing the trigeminal nerve, sensation in the ophthalmic, maxillary and mandibular regions must be tested.
How can sensation of these areas be tested?
Light touch, either with cotton wool or pin pricks
How are the muscles of mastication tested?
Asking patient to clench teeth and feel muscle bulk, feel for asymmetry.
Same thing while asking patient to open mouth
Which two reflexes are associated with the trigeminal nerve?
Corneal reflex
Jaw jerk reflex
What is tested when testing the facial nerve?
-Muscles of facial expression
-Corneal reflex
-Taste
How can the function of the vestibulocochlear nerve be tested?
Rinne’s and Weber’s tests
How is the vestibular function assessed?
Using Dix-Hallpike manoeuvre
Utemberger’s test
What is assessed when assessing the IX and X nerves?
Movement of palate
Gag reflex
Quality of speech
What is assessed when assessing the accessory nerve?
Head turning and shoulder shrugging
What do you look at when assessing the function of the hypoglossal nerve?
Appearance, movement and power of tongue
In the pupillary light response, which nerves are responsible for the -
1. afferent pathway
2. efferent pathway
- CN II (optic)
- CN III (oculomotor)
In the corneal reflex, which nerves are responsible for the -
1. afferent pathway
2. efferent pathway
- CN V (trigeminal)
- VII (facial)
In the jaw jerk, which nerves are responsible for the -
1. afferent pathway
2. efferent pathway
- V (trigeminal)
- V (trigeminal)
In the gag reflex, which nerves are responsible for the -
1. afferent pathway
2. efferent pathway
- IX (glossopharyngeal)
- X (vagus)
In which part of the brain would you find the oculomotor and trochlear nerve nuclei (CN III & IV)?
Midbrain
In which part of the brain would you find the trigeminal, abducent and facial nerves?
Pons
In which part of the brain would you find the vestibulocochlear nerve?
Pontomedullary junction
In which part of the brain would you find the glossopharyngeal, vagus, accessory, hypoglossal cranial nerves?
Medulla
If there was a III, IV and VI nerve palsy, which area of the brain would it arise from?
Superior orbital fissure
If there was a V and VIII nerve palsy, which area of the brain would it arise from?
Cerebellopontine angle
If you see an unusual combinations of cranial nerve lesions, what could this be?
Malignant meningitis
If a patient presents with purely motor signs, what could this be?
Myasthenia gravis
Apart from a cranial nerve lesion, when else may there be cranial nerve signs?
Eye movement disorders
Facial weakness
Difficulty swallowing after a stroke
Which conditions may there be double vision despite a cranial nerve lesion?
Myasthenia gravis
Thyroid eye disease
What can cause the cranial nerves in the brain to be damaged?
Ischaemia
Brain tumour
What can cause the cranial nerves crossing the sub-arachnoid space to become damaged?
Meningitis
What can cause the cranial nerves outside of the skull to become damaged?
Bases of skull fractures arising in the nasopharynx
What causes optic neuritis?
Demyelination of optic nerve causing inflammation
What can optic neuritis cause to happen?
Monocular visual loss
Pain on eye movement
Reduced visual acuity
Reduced colour vision
In those with optic neuritis, what may be seen upon fundoscopy?
Swollen optic disc
Which other condition can optic neuritis be associated with?
Multiple sclerosis
Sympathetic- pupil constriction or dilation?
Dilation
Parasympathetic- pupil constriction or dilation?
Constriction
What can cause dilation of pupils?
Youth
Dim lighting
Anxiety
Cocaine overdose
Mydriatic eye drops
What can cause constriction of pupils?
Old age
Bright lght
Miotic eye drops
Opiate overdose
In which condition is there a smaller pupil in one eye?
Horner’s syndrome
What are some of the causes of an isolated sixth nerve palsy?
Diabetes
Meningitis
Raised intracranial pressure
What can cause nyastagmus?
Congenital
Serious visual impairment
Peripheral vestibular problem
Central vestibular/brainstem disease
Toxins e.g. medications or alcohol
What happens in trigeminal neuralgia?
Paroxysmal attacks of lancinating pain
What is trigeminal neuralgia caused by?
Compression of fifth nerve in the posterior fossa
What is trigeminal neuralgia treated with?
Carbmazepine
What happens in Bell’s Palsy?
Unilateral facial weakness
Is Bell’s palsy an UMN or LMN issue?
Lower motor neuron
What often precedes Bell’s palsy?
Pain behind the ear
How is Bell’s palsy treated?
Steroids
If there is face paralysis caused by an upper motor neuron, what could’ve been the cause?
Stroke or tumour
If there is face paralysis caused by an lower motor neuron, what could’ve been the cause?
Bell’s Palsy
Lyme’s disease
Describe what happens in vestibular neuronitis.
Sudden onset
Disabling vertigo
Vomiting continuously
Dysarthria?
Disordered articulation, slurring of speech
Dysphagia?
Difficulty swallowing
When would dysphagia and dysarthria both be seen?
Bulbar and pseudobulbar palsy
Is bulbar palsy upper or lower motor neuron lesion?
LMN
Is pesudobulbar palsy upper or lower motor neuron lesion?
UMN
In pseudobulbar palsy, the the UML unilateral or bilateral?
Bilateral
What are some of the symptoms of pseudobulbar palsy?
Dysarthria
Dysphonia
Dysphagia
Immobile tongue
Brisk jaw jerk
Brisk gag reflex
In bulbar palsy, the the UML unilateral or bilateral?
Bilateral
Which nerves does bulbar palsy affect?
IX-XII
What are some of the symptoms of bulbar palsy?
Wasted, fasciculating tongue
Dysarthria
Dysphonia
Dysphagia
->Fasiculation = involuntary movements of a muscle, relevant in neuro examination in clinical skills when observing upper and lower limbs
What should you be careful of with patients with pseudobulbar and bulbar palsy?
Beware of feeding these patients due to swallowing difficulties, swallow assessment would need to be undertaken
