cranial nerve examination
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Cranial nerve examinationTRANSCRIPT
Cranial Nerve Examination
Irfan Ziad MD UCDdrkupe.blogspot.com
CN2 :Optic
CN1 :Olfactory
CN3 :Oculomotor
CN4 :Trochlear
CN5: Trigeminal
CN6 :Abducens
CN7 :Facial
CN8: Vestibulocochlear
CN9: Glossoparyngeal
CN10: Vagus
CN11: Accessory
CN12: Hypoglossal
midbrain
pons
medulla
Anterior aspect of midbrain
Dorsal aspect of midbrain
InspectionPosition the patient sitting over the edge of the bed
Look for : Scars (eg. craniotomy), pupil equality, facial asymmetry, ptosis, proptosis, neurofibromas
Hi, my name is _____. Can I examine you?
CN 1CN 1Olfactory Nerve
CN I
Have you ever noticed any change in sense and
smell?
You ask the patient “Have you ever noticed any change in sense and smell?”If the answer is NO, proceed to the next CN
SmellCN 1CN 1Olfactory Nerve
CN I
If the answer is YES, Test: occlude one nostril, close eyes, identify smell (mint, coffee)
Anosmia- loss of the sense of smell (eg. flu, nasal polyps)Lesion- nose, cribiform plate of the eythmoid bone, base of skull- eg meningioma, early sign of parkinson.
SmellCN 1CN 1Olfactory Nerve
CN I
Can you tell me what smell is this?
Optic canal
CN 2CN 2 Optic NerveCN II
Ask patient do they have any difficulty with their vision.
“Can you see the clock on the wall?”“Can you read the newspaper?”
Ask the pt whether she’s myopic (nearsighted) or hyperopic(farsighted)
Visual Acuity
Can you see the clock on
the wall?
CN 2CN 2 Optic NerveCN II
Snellen chart is hold at arm-length
A portable Snellen’s chart will enable you to perform a more formal testA patient who is having visual problems should be asked to count fingers held up in front of each eye in turn, and if this is not possible then perception of hand movement should be assessed. Failing this, light perception only may be present
Visual AcuityCN 2CN 2 Optic NerveCN II
Test acuity with her glasses on. Pinhole if
she forgets her glasses
Confrontation test: ask the pt to look into your eyes while you place our index finger just outside the outer limits of your temporal fields. Move the fingers in turn and then together.
“Point to the moving finger”
In visual inattention (parietal lobe lesions) the patient will only point to one finger when you move both simultaneously.
Point to the moving finger
Visual FieldCN 2CN 2 Optic NerveCN II
Test her peripheral field on each eye separately.
“Can you see the whole of my face?”Can you see the whole of
my face?
Visual FieldCN 2CN 2 Optic NerveCN II
Keep looking at my nose, tell me when you see my finger
moves
Visual Field
Test her left temporal vision against your right temporal vision by moving your wagging finger from the periphery towards the centre
“Tell me when you see my finger moves”
The temporal field should be tested in the horizontal plane and in the upper and lower temporal quadrants.Change hands and repeat on the nasal side
CN 2CN 2 Optic NerveCN II
Bitemporal hemianopia: causes: optic chiasm lesion, pituitary tumour, craniopharyngioma
Right optic nerve lesion
Left Homonymous hemianopia
Left Superior Quadrantanopia
Left Inferior Quadrantanopia
Left homonymous scotoma
2a 2b
2b
1
2
3
4
2+2a
5
6
7
2a+2b Binasal hemianopia: Very rare
Left Homonymous hemianopia with macular sparing
Visual Field
Level of lesions
CN 2CN 2 Optic NerveCN II
Arcuate scotoma- moderate glaucoma
Unilateral defect found with arterial occlusion, branch retinal
vein thrombosis and inferior retinal detachment
Central scotoma- macular degeneration or
macular oedema
Lesions at the level of the retinaThese affect one eye only
Visual Field
CN IICN 2CN 2 Optic Nerve
Tell the pt to look at the tip of your nose. Move the red-headed pin from the temporal periphery through the central field to the nasal periphery, asking the patient
“tell me when the red pin disappears, and reappears.”
“tell me when the red pin disappears
and reappears.”
The blind spot enlarges with papilloedema e.g. raised intracranial pressure with brain tumour. Demyelination of the optic nerve in multiple sclerosis can cause loss of central vision
Blind SpotCN 2CN 2 Optic NerveCN II
This is affected in colour blindness and optic neuritis (loss red colour first).
CN 2CN 2 Optic NerveCN II
Colour Vision
Test is done with an Ishihara plate
FundoscopyTurn on, set diopters to zero, focus on specific distance, look for red reflex, adjust if pt wear glass, look for blood vessels, follow, look at optic disc- clear or blurred?
- Hypertensive, diabetic, papillodema, optic neuropathy, pigmentation (mithocondrial disorder, retinotitis pigmentosa)
CN 2CN 2 Optic NerveCN II
CN 3,4.6CN 3,4.6 Oculomotor, Trochlear, Abducens Nerve
Extraocular movements
CN III, IV, VI
From oculomotor nucleus
Pupillary light reflex
Direct and Consensual: Put your hand in between the patient’s eyes.With a pocket torch shine the light from the side. Do a swinging-light test.
Normally, the pupil into which the light is shone constricts rapidly (Direct light reflex)Simultaneously the other pupil constricts in the same way, (Consensual light reflex)Repeat this procedure on the other side
RAPD (Relative Afferent Pupillary Defect) previous optic neuritis)- swinging light test- damaged nerve dilate in response to lightCauses: eg previous optic neuritis
CN 3CN 3 Oculomotor Nerve
CN III
Accommodation reflex
“Look at that mark on the wall, now look at my finger”
“Look at that mark on the wall, now look
at my finger”
Examine the pupils for size, shape, equality and regularity
PERRLA : Pupils Equal, Round, Reactive to Light and Accommodation
PathologyUnilateral dilated pupil- drugs- cocaine, eye drops (mydriatic)- 3rd nerve palsy- any associated ptosis, strabismus- Holes-Adie pupil- pupil reacts sluggishly, associated with syphilis-Absent light reflex with an intact accommodation reflex occurs in Argyll Robertson pupil in neurosyphilis
CN 3CN 3 Oculomotor Nerve
CN III
Assess for eye movement, diplopia [double vision] and nystagmus
Ask the patient to look laterally left and right, continue moving the finger to complete H pattern.Tell the patient to inform you if they see double images [diplopia]
Diplopia is an early sign of ocular muscle weakness
Without moving your head, follow the pin with your eye. Tell me if you
see double
Extraocular movementsCN 3,4.6CN 3,4.6 Oculomotor, Trochlear, Abducens Nerve
Extraocular movements
SR SR
IRIR
IO
MRLR LR
SO
LR – Lateral RectusMR – Medial RectusSR- Superior RectusIR- Inferior RectusIO- Inferior ObliqueSO- Superior Oblique
CN IV supplies SOCN VI supplies LRCN III supplies all others + levator palpebrae superioris (which elevates the superior eyelids)
CN 3,4.6CN 3,4.6 Oculomotor, Trochlear, Abducens Nerve
Complete ptosisEye down and outDilated pupil which is not responsive to light and accommodation.
Double vision going down stairs or reading booksAsk patient to turn the eye in and then to look down- may cause vertical hypertropia (pic)
Failure of lateral movementNystagmus.
3rd nerve palsy 4th nerve palsy 6th nerve palsy
Extraocular movements
NystagmusThe direction of nystagmus is defined as that of the fast [correcting] movement
Vestibular lesion – nystagmus away from the side of the lesionCerebellar lesion – nystagmus to the side of the lesion
Internuclear ophthalmoplegia Abducting eye has greater nystagmus than the adducting eye. Problems btw nuclear, 3rd n 6th connected by medial longitudinal fasciculus (MLF) - MS
CN 3,4.6CN 3,4.6 Oculomotor, Trochlear, Abducens Nerve
CN 5CN 5 Trigeminal NerveCN V
Sensory branch
Ophthalmic (V1)
Maxillary (V2)
Mandibular (V3)
Motor Muscle of mastication
Masseter
Temporalis
Medial pterygoid
Lateral pterygoid
Tensor veli palatini
mylohyoid
Anterior belly of digastric
Tensor tympani
Others
All involved in biting, chewing, swallowing except for tensor tympani which acts to dampen sound produced from chewing
Masseter
Temporalis
Trigeminal Nerve
Test for soft touch using cotton wool - sternum first, close eyesin the 3 divisions of the nerveV1- ophthalmic- forehead up to the top of the headV2- maxillaryV3- mandibular (up to angle of the jaw)
The patient should be instructed to say “yes” each time the touch of the cotton wool is felt. Do not stroke the skin touch it.Test for pain using sharp object.Ask patient does it feel sharp or dull
Causes of sensory problems- MS- MS plaque in the brainstem in young people- Sjogren- dry eyes, dry mouth-Trigeminal neuralgia- older people
Facial Sensory
Say “yes” if you feel this
CN 5CN 5 Trigeminal NerveCN V
Ask the pt to look up and away, touch the corneal. Reflex blinking of both eyes is a normal response.
PathologyBell’s palsy- unable to blink due to damage to the efferent limb (CNVII)CNV forms the afferent limb
Corneal Reflex
I’m going to gently touch your eye with a cotton bud.
CN 5CN 5 Trigeminal NerveCN V
Inspect for wasting of the temporal and masseter musclesAsk patient to clench their teeth and palpate for contraction of the temporal and masseter muscles
Motor
Can you grit your teeth, please?
CN 5CN 5 Trigeminal NerveCN V
Ask patient to open their mouth and hold it open while the examiner attempts to force it shut [pterygoid muscles].
A unilateral weakness of the motor division causes the jaw to deviate towards the weak side.If weakness is suspected patients should be asked to move the jaw laterally against resistance. The jaw can be moved towards the affected muscle but cannot move towards the normal side.
Motor
Open up your mouth and hold it for me
CN 5CN 5 Trigeminal NerveCN V
Ask the pt to open her mouth fully, and close halfway, , place index finger on her chin and tap with a patella hammer, if jaw jerk is highly exaggerated.
Help to distinguish btw pseudobulbar palsy (UMN lesion of lower cranial nerve 9, 10,11,12) and a bulbar palsy (LMN lesion of lower cranial nerve 9,10,11,12)
The Jaw Jerk
I’m going to gently tap your jaw
CN 5CN 5 Trigeminal NerveCN V
CN 7CN 7 Facial NerveCN VII
Facial canal (tortuous course)
Internal auditory meatus
Geniculate ganglion
Stylomastoid foramen
Temporal
Zygomatic
Buccal
Mandibular
Cervical
Major facial branches
Inside SkullOutside skull
Other
Posterior auricular nerve
Posterior belly of Digastric
Stylohyoid muscle
Stapedius
Frontalis, orbicularis oculi
Z1: Eye & around orbitZ2: Mid face & smile
Buccinator, upper lip
Lower lip, orbicularis oris
Platisma
controls scalp muscles around the ear
3. SENSORY
2. PARASYMPATHETIC
Greater petrosal to Lacrimal gland, sphenoid sinus, frontal sinus, frontal sinus, maxillary sinus, eithmoid sinus, nasal cavity,
The facial nerve has four components:
1. BRANCHIAL MOTOR
4. TASTE
From facial nerve nucleus
Small contribution to external acoustic meatus
Palate via greater petrosalAnt 2/3 tongue via chorda tympani
From Nevus Intermedius
Petrous temporal bone
Ask the patient to shut the eyes tightlyObserve and try to force open each eye.
If a lower motor neuron lesion is detected [weakness on one side of face], check for ear and palatal vesicles of herpes zoster of the geniculate ganglion – the Ramsay Hunt syndrome
Motor
Shut your eyes tightly and don’t let me open them
CN 7CN 7 Facial NerveCN VII
Ask patient to look up and wrinkle her forehead. Feel for muscle strength by pushing down on forehead.
This movement is preserved on the side of an upper motor neurone lesion [a lesion which occurs above the level of the brainstem nucleus], because of bilateral supranuclear innervation giving some compensation to the upper face which is not the case in LMN lesion (Bells palsy/Ramsay Hunt- Herpes Zoster)
The remaining muscles of facial expression are usually affected on the side of an UMN lesion.In a LMN lesion all muscles of facial expression are affected on the side of the lesion.
Motor
Wrinkle your forehead for me please
CN 7CN 7 Facial NerveCN VII
Ask the patient to show their teeth
Compare the nasolabial grooves which are smooth on the weak side.
Left upper motor neuron seventh nerve lesion leads to drooping of the corner of the mouth, flattened nasolabial fold, and sparing of the forehead on the left side**
Motor
Show me your teeth
CN 7CN 7 Facial NerveCN VII
Ask the patient blow out her cheeks
Motor
Blow out your cheeks
CN 7CN 7 Facial NerveCN VII
CN 7CN 7 Facial NerveCN VII
Upper Motor Neurone Lower Motor Neurone
Pathway Rt motor cortex-corona-radiata-internal capsule-brainstem (midbrain-pons-medula)-crosses- anterior horn cell-
Anterior horn cell, intervertebral foramen, lumbar sacral(lower limb)/brachial plexus(upperl imb plexus, runs in peripheral nerve- stop at NMJ
Presentation increased tone, reflex, clonus, upgoing(extensor) plantar
- wasting, fasciculation, lose of tone, reflex, flexor plantar
Cerebrovascular accidentstroke! most common
Intracranial tumourCervical spine injury
Motor neuron diseasePeripheral nerve neuropathy
Diabetic neuropathy?Poliomyelitis
anterior horn cell affectedSpinal cord injury
with nerve root compression
CN 8CN 8 Vestibulo-Cochlear NerveCN VIII
Cochlear division- HearingFrom organ to Corti in cochleaHair cells to cell bodies in spiral ganglion (in modiolus)To 2 cochlear nuclei (ventral & dorsal)
Vestibular division – BalanceFrom semicircular canals, utricle & sacculeCell bodies in vestibular ganglion in outer part of internal acoustic meatusTo 4 vestibular nuclei (medial, lateral, superior, inferior)
Any problem with hearing? Hearing aids?Mask- cover the tragus of the ear and whisper a number, ask pt to repeat
If deafness is suspected perform Rinne’s test and Weber’s test
Hearing+Balance
I’m going to whisper a number. I want you to
repeat it.
CN 8CN 8 Vestibulo-Cochlear NerveCN VIII
Rinne’s Test
Rinne- base of tuning fork on the mastoid process,
“tell me when it stops”, then bring it to the ear,
“Can hear it? “
With nerve deafness the note is audible at the external meatus, as air and bone conduction are reduced equally, so that air conduction is better as is normal. This is termed Rinne-positive.With conduction [middle ear] deafness no note is audible at the external meatus. This is termed Rinne-negative.
Can you hear it?
CN 8CN 8 Vestibulo-Cochlear NerveCN VIII
Weber’s Test
A vibrating tuning fork is placed on the centre of the forehead. Normally the sound is heard in the centre of the forehead. With nerve deafness the sound is transmitted to the normal ear. With conduction deafness the sound is heard louder in the abnormal ear.
Patients with defective hearing should be referred for audiometry. This measures the degree of hearing loss at different sound frequencies.
Can you hear it?
CN 8CN 8 Vestibulo-Cochlear NerveCN VIII
CN 9CN 9 Glossopharyngeal NerveCN IX
CN 10CN 10 Vagus NerveCN X
CN 9, 10CN 9, 10 Glossopharyngeal and Vagus NerveCN IX, X
Uvula + Gag Reflex
UvulaGet the patient to open their mouth and inspect the palate with a torch. Note any displacement of the uvula. Ask the patient to say ‘Ah’. If the uvula is drawn to one side this indicates a unilateral tenth nerve palsy. The uvula is pulled towards the normal side.Now test gently for the gag reflex
Ninth is the sensory componentTenth is the motor component
Gag ReflexTouch the back of the pharynx on each side with a spatula. Ask the patient if the touch of the spatula is felt each time. Normally there is reflex contraction of the soft palate.
The ninth nerve supplies taste from the posterior two-thirds of the tongue this is not routinely tested for.
CN 9, 10CN 9, 10 Glossopharyngeal and Vagus NerveCN IX, X
Open your mouth and say “ah”
CN 12CN 12 Hypoglossal NerveCN XII
Its nucleus receive Corticonuclear fibers from both cerebral hemispheres, but the cells supplying the genioglossus muscle receives corticonuclear fibers only from the opposite cerebral hemisphere It supplies1. All the intrinsic muscles of the tongue2. Styloglossus3. Hyoglossus4. Genioglossus5. Doesn’t supply Palatoglossus – Supplied by the vagus Function is to control the movement of the tongue In the upper part, the Hypoglossal nerve is supplied by the C1 fibers
CN 12CN 12 Hypoglossal NerveCN XII
Motor Nerve of Tongue
Observe the tongue at rest- wasting? on one side? fasciculation?Stick out tongue straight- deviate to one side?Tongue deviate to the side of a lesion of CNXII
Wiggle tongue side-to-side - (coordination)altered in cerebellar disorder
Wiggle your tongue side-to-side
Cranial Root Spinal Root
Receives corticonuclear fibers from both cerebral hemispheres
It joins the spinal root & leaves the skull through jugular foramen
Then the roots separate again, cranial root joins the vagus
Situated in the anterior grey column of the spinal cord in the upper 5 cervical segments
Nerve fibers emerge from the spinal cord & form a nerve trunk that ascends into the skull through the foramen magnumSpinal part joins the cranial part & pas through the jugular foramenThen they separate again
Supply the muscles of:Soft palate (Except tensor veli palatini)Pharynx (Except stylopharyngeus)Larynx (Except cricothyroid)
Supplies the SCM muscle & trapezius muscle
CN 11CN 11 Accessory NerveCN XI
Trapezius
Ask the patient to shrug their shoulders and feel the bulk of the trapezius muscles and attempt to push the shoulders down.
CN 11CN 11 Accessory NerveCN XI
Shrug your shoulder, push up against my
hand
Sternocleidomastoid
Ask the patient to turn their head against resistance and feel the bulk of the sternomastoids. Feel for the sternomastoid on the side opposite to the turned head. There will be weakness on turning the head away from the side of a muscle whose strength is impaired.
(Optional)Test neck flexors if suspect myasthenia gravis, MND- “put chin on chest, I’ll put my hand onto
your forehead, push up against my hand”
CN 11CN 11 Accessory NerveCN XI
Turn your head against my hand
Thank You