Cranial nerves can be damaged at different levels, resulting in upper or lower motor neuron weakness. Examination of the cranial nerves involves testing specific functions like smell, vision, eye movements, facial expression, hearing, swallowing and tongue movement. Common causes of cranial nerve lesions include tumors, infections, strokes and traumatic injuries. Examinations allow localization of lesions to particular cranial nerves or levels of the nervous system.

1. CRANIAL NERVE LESIONS
AND EXAMINATION

2. Cranial nerve palsy
•The upper motor neuron –
lesion results in an upper motor
neuron weakness, central palsy
• in: cortex, internal capsule, or
brain stem above the nucleus
•The lower motor neuron –
lesion results in an lower motor
neuron weaknesss, peripheral p.
• in: the nucleus in the brain stem
(the cell bodies form nuclei),
or in any lower part of the
cranial nerve

3. Olfactory nerve disorders
•hyposmia/anosmia: bilateral and transient – rhinitis
• unilateral:
• damage of the fila olfactoria – through cribriform plate of the ethmoid bone
head trauma - skull fractures
• olfactory bulb and tract damage – tumours – meningeoma, glioma
•uncinate fits – olfactory hallucinations (unpleasant)
lesion in the olfactory cortex (uncus gyri hippocampi) – tumour - glioblastoma

4. Olfactory nerve examination
• Testing the ability to smell or to identify different smells:
• each nostril separately
• the patient tries to identify the odor with eyes closed
• recommended:
perfume (flowers), spice (cinnamon, peppermint…), coffee,
tobacco, soap…
• avoid substances which irritate the trigeminal nerve (ammonia,
vinegar…)

5. Optic tract and manifestations of its damage
• the ocular systém reverses the image
• optic chiasma – partial decussation
• damage anterior to the chiasma:
• scotoma
• monocular blindness
• lesion at the chiasma:
• heteronymous hemianopsia
• damage posterior to the chiasma:
• homonymous hemianopsia
• lesion in the optic radiation:
• quadrantanopsia
• lesion to the visual cortex:
• one side – homonymous hemianopsia
• bilateral – cortical blindness
Mumenthaler

6. Optic nerve examination
•visual acuity
•optic fundus and disc:
• papilloedema – prominence is
measured in dioptres
• in increased intracranial pressure
(brain tumour?)
• contraindication of lumbar
punction!
•visual fields – gross testing by
confrontation

7. ISHIHARA CHART

8. TYPES OF EYE MOVEMENTS

9. NYSTAGMUS

10. Impaired ocular movement
•Disorders of gaze
• vertical
•upward gaze and
convergence are lost
•in midbrain tectum
lesion
= Parinaud´s syndrome
Netter

11. Impaired ocular movement
Lesions of the cranial nerves (peripheral
palsy):
• III (oculomotor)
• IV (trochlear)
• VI (abducens)
•with paralytic strabismus
•with double vision (diplopia)

13. Oculomotor palsy
• ptosis (levator palpebrae m.)
• divergent strabismus (the affected
eye deviates downwards &
laterally)
• paralysis of the eye movements and
accommodation
• pupil dilatation (mydriasis),
• reaction to light is absent

14. Oculomotor palsy - paralysis of the eye
movements (left eye)

15. Oculomotor palsy (on the right side)
•divergent strabismus
•mydriasis
•paralysis of the eye movements
Perkin

17. Trochlear palsy
•rare
•weakness of downward gaze
•double vision when looking
downwards
•the head may tilt to the
opposite side to minimise the
diplopia
•diplopia is vertical and
torsional
Right fourth nerve palsy, the
paretic eye turns up- and
outwards; head tilting

18. Abducent palsy
• convergent strabismus
• failure of abduction
on the affected eye
(on looking to the paralysed
side)
• horizontal diplopia
Left sixth nerve palsy
(looking to the left)

19. III, IV, VI cranial nerve examination
•palpebral fissures (symmetrical? ptosis?)
•position of the bulbs (parallel? strabismus convergent
or divergent?)
•ocular movements (full range? limitations?)
•nystagmus (direction? degree?)
• pupils: shape, size in mm (dilated – mydriasis,
constricted – miosis)
equality (isocoria? anisocoria?)
reaction to light (light reflex):
direct and consensual
near reaction to accommodation and convergence

20. Trigeminal nerve disorders
•the fifth nerve:
• sensory fibres subserve facial
sensation (half of the face, 3
divisions)
• motor fibres (in the
mandibular division)
innervate the muscles of
mastication (masseter,
pterygoids and temporalis)
•disorders:
• sensory loss
• muscle weakness, atrophy
(in peripheral palsy)
• neuralgia

21. Trigeminal nerve examination
•pressure to points where the divisions emerge –painful
•sensation (each division separately) for
• pain
• temperature
• light touch
•corneal reflex – blink response (trigemino-facial r.) –
symmetrical?
•masseter reflex (jaw jerk)
• motor function of the masseter, temporal and
pterygoid muscles

34. Facial nerve examination
• observation
• testing of the upper branches:
• to wrinkle forehead (raise eyebrows)
• to frown
• to close eys tightly (persisting fissure in mm)
• to close eyes against the resistance
• testing of the lower branches:
• to smile
• to show one´s teeth
• to purse the lips up
• to blow out the cheeks
• to whistle

35. Facial palsy
• upper motor neuron lesion,
central paralysis:
the upper branch is less affected
(because the rostral part of the
nucleus is innervated bilaterally)
paralysis is marked on the muscles
in the lower half of the face,
on the opposite side
• lower motor neuron lesion,
peripheral paralysis:
paralysis of all facial muscles
on the same side
Mumenthaler

39. Facial palsy
Peripheral:
• the upper branches
• flattened wrinkles on the forehead
• lagophthalmos
an attempt to close the eyes -
the one eye does not close
• Bell´s phenomenon
the eyeball rotates upwards

40. Facial palsy
Peripheral:
• the lower branches
• flattening of nasolabial fold
• mouth angle drop
• asymmetrical:
• smile
• showing teeth
• purse lips

48. CRANIAL NERVE VIII: AUDITORY NERVE
• FUNCTIONS
• 1 The cochlear nerve. This carries impulses of sound from the hair cells of
the organ of Corti, through the spiral ganglion in the cochlea, to the cochlear
nuclei in the pons. Most fibres cross, run in the lateral lemniscus to the
medial geniculate body and are relayed to the superior temporal gyrus. But
there is some uncrossed upwards transmission, so that deafness from a
unilateral cerebral cortical lesion is virtually precluded.
• 2 The vestibular nerve. Impulses arise in the labyrinth by displacement of
endolymph affecting the hair cells in the ampullae of the semicircular canals,
and the otoliths in the saccule and utricle. Fibres run to the vestibular
ganglia and on in the main trunk of the nerve to the vestibular nuclei in the
medulla. These nuclei have connections with the cerebellum, the
oculomotor nuclei via the medial longitudinal bundle, the nuclei of the
upper cervical nerves, the spinal cord and the temporal lobes

49. • EXAMINATION
• Test environment
Explain the test procedure.
Ensure a reasonably quiet environment.
Test procedure
Acoustic branch - check their hearing from the external auditory
meatus, either by whispering or by rubbing fingers lightly together.
Interpretation
If you suspect reduced hearing acuity decide if the problem is one of
the sound conduction through the ear (conductive deafness) or
conversion of sound into nerve impulses (sensori-neural deafness).

50. • RINNE'S TEST
➤ Test procedure
Place vibrating tuning fork on the mastoid and ask the patient
to say when it has stopped. When the patient says the sound
has stopped, hold the fork at the meatus, rotating it slightly.
Interpretation
If the sound is still heard air conduction>bone conduction this is
found in sensori-neural deafness.
If not heard bone conduction>air conduction - the finding in
conductive deafness.

51. • WEBER'S Test
Test procedure
Hold vibrating tuning fork in the middle of the patient's forehead. Ask
in which ear the sound is loudest.
interpretation
It should be heard equally loudly in both ears
It should be located more on one side then conductive deafness exists
on that side or the opposing ear has sensori-neural deafness.
• Tests of vestibular function
• 1. rotational test
• 2. caloric tests

52. • CONDUCTION DEAFNESS
• • All diseases of the external meatus,
middle ear, and Eustachian tubes
• • Middle ear infection in suspected
intracranial infection
• • Certain middle ear tumours (e.g.
tumours of the glomus jugulare
• PERCEPTION DEAFNESS
• At cochlear level - Meniere's disease,
advanced otosclerosis, deaf ness due to
drugs, internal auditory artery
occlusions, prolonged exposure to loud
noise
• • In the nerve trunk - Old age, post-
inflammatory lesions, toxic lesions,
meningitis, cerebellopontine angle
tumours, trauma
• • In the brainstem - Severe pontine
vascular lesions, severe demyelinating
lesions, occasionally tumour
• CAUSE OF VESTIBULAR DISTURBANCES
• 1. At labyrinthine level
• (a) Meniere's disease
• (b) Motion sickness
• (c) Drug toxicity
• (d) Probably migraine
• 2. In the vestibular nerve. As for
perception deafness, but add also
'vestibular neuronitis’
• 3. In the brainstem
• (a) Vascular deficiency, especially
vertebrobasilar artery disease
• (b) Cerebellar and IVth ventricular
tumours
• (c) Acute demyelinating disease,
migraine
• 4. In the temporal lobe. As an epileptic
manifestation, especially in children, or
as an ischaemic lesion in the elderly

53. CRANIAL NERVE IX&X: GLOSSOPHARYNGEAL
&VAGUS
• FUNCTION
• the following functions are of most importance in neurological
examination
• 1 To carry common sensation from the pharynx, tonsils, soft palate
and posterior one-third of the tongue.
• 2 To carry the sense of taste from the posterior one-third of the
tongue (probably almost purely by the IXth nerve).
• 3 To give motor supply to the palatal and pharyngeal muscles.
• 4 To give motor supply to the vocal cords (purely the vagus).

54. • EXAMINATIONS
• Preliminary observation
• Notice the pitch and quality of the patient's voice, and of his cough,
and whether there is any difficulty in swallowing his saliva. Ask if there
has been any nasal regurgitation of fluids.
• A high-pitched, hoarse voice may mean vocal cord paralysis
• A nasal tone that increases if the head is bent forwards means palatal
paralysis, when lying back this can become almost normal.
• If the patient chokes on his saliva while talking, there may be both
palatal and pharyngeal weakness
• Motor functions
• Ask the patient to open his mouth wide. The patient is then asked to
say 'Ah' while breathing out, followed by 'Ugh' while breathing in. In
each case, the palate should move symmetrically upwards and
backwards, the uvula remaining in the midline, and the two sides of
the pharynx should contract symmetrically.

55. • Sensory functions
• A throat swab, with the cotton wool safely attached, is passed to one side of the
back of the throat, while the tongue is gently and slowly depressed. Touching any
part of the palate, tonsil or the back of the tongue will normally result in
contraction of the pharynx, elevation of the palate and retraction of the tongue.
This is called the gag reflex, and varies in sensitivity from individual to individual
• Taste
• Testing taste on the posterior part of the tongue is so difficult by normal means
• INTERPRETATIONS
• On phonation
• The palate moves up and over to one side when there is paralysis of the opposite
side, owing to the pulling movement of the unopposed normal muscle.
• In pharyngeal paralysis, the muscles will also appear to move towards the normal
side, so resembling a flat sheet being drawn across that it is called the 'curtain
movement’(caused by lmn lesion)
• If there is no movement of the palate and pharynx, there should also be dysphagia,
nasal regurgitation and nasal speech, and this usually indicates either a bilateral
medullary nuclear lesion or a umn lesion

56. ON TESTING SENSATION
Unilateral absence of the gag reflex may be due to loss of sensation, or
motor power or both. Phonation will have shown if one side is
paralyzed. If due to loss of sensation alone, stimulation of the normal
side will produce a normal symmetrical reflex. This rare event would
be due to a glossopharyngeal lesion. If the defect, however, is due to
combined motor and sensory paralysis, stimulation of the normal side
will cause the palate to be pulled towards that side. This more
common finding indicates a combined lesion of glossopharyngeal and
vagus nerves

57. CRANIAL NERVE XI: ACCESSORY NERVE
• Functions
• To supply motor power to the upper part of the trapezii and to the
sternomastoid, and so to influence the posture and movements of
the head and shoulder girdles
• EXAMINATION
• 1 STERNOMASTOIDS
• Place one hand against the right side of the patient's face and ask
him to turn (not bend) his head against it. The left sternomastoid will
stand out clearly . Repeat this in the opposite direction and compare
the two sides for bulk and strength. Then rest a hand on his forehead
and ask him to bend his head forwards. Both sternomastoid will
stand out together and are easily compared . Now ask the patient to
sit up. Normally, the head leaves the pillow first and the movement is
easy

58. • 2 TRAPEZIUS
• Go behind the patient and compare the line and curve of the trapezii
and the position of the scapulae, making certain that he is sitting
symmetrically upright. Then ask him to raise his shoulders towards
his ears. (Asking patients to 'shrug their shoulders' often produces a
most unnatural convulsive movement.) Now try to depress the
shoulders forcibly. Even the most feeble patient is normally able to
resist the manoeuvre

59. • INTERPRETATIONS
• 1. In bilateral sternomastoid weakness, when the patient sits
up, the head seems to be left behind on the pillow and then is
raised with difficulty
• 2. In unilateral sternomastoid weakness, the patient will fail to
turn his head against resistance to the opposite side
• 3. Trapezius -weakness results in the shoulder dropping on one
side and the scapula being displaced downwards and laterally,
giving a steeper gradient to the contour of the neck. Shrugging
of that shoulder may be weaker, though not absent, because
part of the trapezius is supplied by cervical nerves
LESIONS OF XI CRANIAL NERVE
NUCLEAR XI NERVE: MND, SPINAL MUSCULAR ATROPHY POLIOMYELITIS
NERVE: POLYNEUROPATHY OR MONO NEUROPATHY
MUSCLE: POLYMYOSITIS, DERMATOMYOSITIS MYASTHENIA GRAVIS , OCULOPHARYNGEAL MUSCULAR DYSTROPHY

60. Cranial nerve xii: hypoglossal
• Functions
• To control all movements of the tongue, and certain movements of the hyoid bone and larynx during and after
deglutition
• Examination.
➤ Test procedure
Ask the patient to put out the tongue.
➤Interpretation
If deviated then that is the weak side.
Look for fasciculation or wasting with tongue in the mouth.
These indicate an infranuclear lesion

65. Common lesions of hypoglossal nerve
LOWER MOTOR NEURON LESIONS
UNILATERAL
1. SYRINGOMYELIA
2. POLIOMYELITIS
3. TRAUMA
4. ANGIOMAS
5. EARLY MOTOR NEURON
DISEASE
BILATERAL
1. PROGRESSIVE BULBAR PALSY
2. SYRINGOMYELIA
• UPPER MOTOR NEURON
LESIONS
• UNILATERAL
• 1. Profound hemiplegia (due to
vascular accidents or deep-
seated neoplasms)
• BILATERAL
• . Bilateral vascular accidents
producing a pseudobulbar palsy,
amyotrophiC

66. Bulbar and pseudobulbar palsy
bulbar (nuclear)
• bilateral affection of the lower
cranial nerves IX-XII or their nuclei in
the oblongata
• lower motor neuron lesion,
peripheral palsy
• dysarthria, dysphagia, n.VII,V
• masseter reflex absent
• tongue atrophy, fasciculations
• cause: polyradiculoneuritis - Guillain-
Barré syndrome), brainstem lesions –
tumours, meningoencephalitis,
motor neuron disease
pseudobulbar
(supranuclear)
• bilateral lesion of cortico-bulbar
tract
• upper motor neuron lesion, central
palsy
• dysarthria, dysphagia, n.VII,V
• masseter reflex increased
• emotional lability (unprovoked
crying or laughing)
• frontal type of the gait
• cause: cerebrovascular disease,
arteriosclerosis (multi-infarct
conditions)