Download Cranial Nerve VIII

I
II
III
V
VII&VIII
VI
IX &X
XII
XI
Cranial Nerve I:
Olfactory
Bulbus
olfactorius
Foramen: cribiform
plate of ethmoid
Region Entered:
nasal cavity
Components:
special sensory
Target: olfactory
epithelium
Function: smell
50 million primary sensory receptor cells in 2.5 cm2
Bipolar
cells
Second neurons:
First neurons: Unmyelinated
8-20 cilia of 30-200  in length
The mucous lipids assist in transporting the
odorant molecules as only volatile materials
soluble in the mucous, can interact with the
olfactory receptors & produce the signals that our
brain interprets as odor
60  thick layer of mucous (lipid- rich
secretion that bathes the surface of the
receptors at the epithelium surface)
Lateral stria
anterior olfactory nucleus
pyriform cortex
olfactory tubercle
transitional entorhinal cortex
nucleus of horizontal limb of diagonal band
Medial stria
Olfactory Tract Connections& Lesion
 Lateral stria
primary olfactory cortex
(periamygdaloid & prepiriform areas)
secondary
olfactory cortex (entorhinal area (area 28))
 Medial stria
cross the anterior commisure to
join contralateral olfactory bulb
Unilateral anosmia : Compression due to abcess, glioma,
meningioma of frontal lob or hypothalamus which may
result in ipsilateral optic atropy & contralateral papilledema
Foster-Kennedy syndrome
Cranial Nerve II:
Opticus
Foramen: optic
canal of sphenoid
Region Entered:
orbit
Components:
special sensory
Target, Function:
retina-vision
1st neurone: rod & cone cells of the
retina
2nd neurone: bipolar neurones of the
retina
3rd neurone: multipolar neurones of
the retina
Axons of the ganglion opticum run
via the N. opticus to the chiasma
In the chiasma opticum, fibres of the
nasal part of the retina cross to the
contralateral side, and those of the
temporal part continue ipsilaterally
Each tractus opticus consists of
fibres transporting the information
from the contralateral halves of the
visual field
corpus geniculatum
laterale&mediale (some fibres),
hypothalamus
go directly to the
cortex of the brain
4th neurone: corpus geniculatum
laterale
areas 17&18 around the
sulcus calcarinus (area striata)
Acute right homonymous hemianopsia in a 59-year-old man due to
embolus in the left PCA. (A) MRI shows infarction in the medial left
occipital lobe (arrow). (B) Occlusion of the left PCA at its origin
(arrow) by an embolus (DSA, left vertebral artery, AP view). (C) The
capillary phase (arrow) is absent in the left occipital lobe due to the
proximal embolus.
Causes of Papillitis&Retrobulbar Neuritis
 Multiple sclerosis
 Viral illness; Syphilis
 Temporal arteritis & other kinds of
inflammation of the arteries (vasculitis)
 Poisoning by chemicals: lead, methanol...
 Tumors that have spread to the optic n.
 Allergic reactions to beestings
 Meningitis
 Uveitis
 Arteriosclerosis
Superior Orbital
Fissure Syndrome
IV
VI
III
preganglionic parasympathetic
to: ciliary ganglion (innervation of
sphincter pupillae and ciliary
muscle)
Cranial Nerve III:
Oculomotor
R eye
Foramen: Superior
orbital fissure
Region Entered: Orbit
Somatomotor Comp.:
Target, Function:
levator palpebrae sup.
superior rectus
medial rectus
inferior rectus
inferior oblique
Visceromotor Comp.:
preganglionic
parasympathetic to:
ciliary ganglion
THIRD CRANIAL NERVE PALSIES
During primary gaze, weakness of
the muscles innervated by, result in:
 Ptosis of the lid
 Mydriasis
 Outwardly turned eye
Pupil is completely spared:
• Myopathy
• but all other muscles innervated by the
3rd nerve are affected: diabetic 3rd
nerve paresis (ischemic process)
Fixed dilated pupils: 3rd nerve compression
- Aneurysm of the post. communicating art
- Trauma
- Intracranial mass lesion
- Increasingly unresponsive patient with
3rd n. palsy: transtentorial herniation
Neurologic examination with CT or MRI
• When CT does not show blood: Lumbar
puncture (suspected SAH)
• Cerebral angiography: if aneurysm is
suspected
+
Nuc. Ruber infarction in midbrain
contralat. tremor + İpsilat.
3rd n. palsy & fixed pupilla
Pupillary Reflex:
Afferent: NII
Edinger-Westpal nuc.
Efferent: NIII parasympath.
Argyll Robertson pupil
Accomodation Retained
Light reflex absent
• Ptosis
• Myosis
• Enophthalmus
• Loss of sweating on the affected side of the face
From hypothalamus, sympathetic nn. descend
ipsilat. through the brainstem & cervical cord & riches
the sympathetic chain via the motor root of T1. From
there, fibers pass along the outer sheath of the internal
carotid artery&its opht.branch &to the pupilla. Fibers to
the face travel with the ext. carotid artery
Pancoast tm, mass compress. cervical symp. chain
Superior Orbital
Fissure Syndrome
IV
VI
III
Cranial Nerve IV: Trochlear
Foramen: Superior orbital fissure
Region Entered: Orbit
Components: somatomotor
Target, Function: Superior oblique
muscle
Cranial Nerve IV: Trochlear
 Affect vertical eye position
when the eye is turned inward
 The patient sees double images:
one above & slightly to the
side of the other
 By tilting the head to the side
opposite the palsied m., the pt
may achieve full ocular motility without double vision
Causes: idiopathic, closed head trauma, aneurysms, tm, MS
Cranial Nerve VI:
Abducens
Foramen: Superior
orbital fissure
Region Entered:
Orbit
Components:
Somatomotor
Target, Function:
to lateral rectus
(best abductor!)
• Idiopathic: improvement within 2 mo
• Elderly or diabetic pts: small vessel disease
• Compression in cavernous sinus: severe
headache & anesthesia in the area of n.V1
• Increased intracranial pressure:
shift in the brain stretch the 6th n.
• Trauma (basilar skull fracture)
• Infections & tumors affecting the meninges
• Aneurysm, MS
• Wernicke's encephalopathy
Saccadic Eye Movements
Frontal eye
field
(FEF & SEF)
P
P
R
F
geniculatum lat.
Mesensephalon
ııı
VI
ıv
Nuc. Abducens
vı
VIIIN
MLF MLF
Optik nerve
Corpus
Lat. rectus Medial rectus
MLF
Retina
Area 17. & 19.
FEF
Pons
Mesencephalon
Pons (VI. contral.
III. & n. nuclei)
Saccadic Eye Movements
Frontal eye field
(FEF & SEF)
Lateral rektus
MLF
VI
ııı
Medial rektus
Mesencephalon
ıv
Nuc.VI Pons
P
vı
P
VIII
R MLF MLF
F
Saccadic Eye Movements
Frontal eye field
(FEF & SEF)
Lateral rektus
Medial rektus
MLF
VI
ııı
P
P
R
F
Mesencephalon
ıv
Nuc. Abducens Pons
vı
VIII
MLF MLF
Vertical Gaze
• Bilateral control
• Center: Dorsal rostral
mesencephalon
• 3 integral structures:
- riMLF
- Cajal’s interstitial nuc.
- Posterior commisure
• Inputs from PPRF &
vestibular nuclei
• Each riMLF projects
ipsilaterally to III & IV n.
nuclei
Vestibulo-ocular Reflexe paths
Rapid turn of the head to the left
Ant. motion of the
fluid in the labyrinth
Cupula is stimulated
Ipsilat. IIIrd & contralat. VIth
nerves are stimulated
Eyes turn right in order to
sustain forward gaze
Cranial Nerve V: Trigeminal
V1-Trigeminal ophthalmic
Major branches: Lacrimal, Frontal, Nasociliary & Meningeal
Foramen: superior
orbital fissure
Region Entered: orbit
Components: general
sensory
Target, Function:
general sensation
from skin and
mucosa in region
at & above orbit
V. NERVUS TRİGEMİNUS
Duysal
 Yüz
 Oral-nazal kavite
Dilin 2/3 ön kısmı: Ağrı-ısıdokunma
Meninksler: Ağrı
Motor
Çiğneme kasları, tensor veli palatini
Refleks Kornea-Göz kırpma, çene
SUPRANÜKLEER LEZYONLAR: Vasküler, demiyelinizan, tümör
Bilateral-yaygın premotor
nöron lezyonları
 Çiğneme kasları paralizisi
 Çene refleksi 
 Bilateral premotor nöron bulguları
 Affekt kontrol bozukluğu, demans
Talamik lezyonlar
Karşı yüz yarımında his kusuru
Parietal lezyonlar
Karşı taraf kornea refleksi kaybı  hemifasiyal his
kusuru
Cornea
Reflex
• Afferent:
N V1
• Efferent:
N VII
(blink)
Ciliary
ganglion
V2-Trigeminal maxillary
Infraorbital, Zygomatic,Nasopalatine, Palatine
Foramen:rotundum
Region Entered:
pterygopalatine fossa
Components:
general sensory
Target, Function:
gen.sensation from
skin & mucosa
in region from
orbit to mouth
V3-Trigeminal mandibular
Buccal, Auriculotemporal, Lingual, Inf. alveolar & Meningeal
Foramen: ovale
with lesser petrosal
from CN9
Region Entered:
infratemporal fossa
Components:
brachiomotor
Target, Function:
muscles of masticat.
tensor tympani & veli
palatini, mylohyoid
ant. belly digastric
 Lesion of spinal tract V
IPSILATERAL deficits
in pain & temperature from the face etc.
(the pain information never gets to the
caudal spinal nucleus)
 Interruption of the trigeminothalamic tract
deficits in pain & temperature on the
contralateral side of the face
(comprised of axons that have crossed
the midline)
Causes of Sensory Trigeminal Neuropathy
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Idiopathic
Systemic inflammatory disease
Sjögren's syndrome
Progressive systemic sclerosis
(scleroderma)
Mixed connective tissue disease
Systemic lupus erythematosus
Dermatomyositis
Rheumatoid arthritis
Sarcoidosis
Wegener's granulomatosis
Undifferentiated connective tissue
disease
Giant cell arteritis
Idiopathic hypertrophic cranial
pachymeningitis
Multiple sclerosis
Tumor
– Intracranial or extracranial
– Metastatic
– Primary: Meningioma, Schwannoma,
Epidermoid, Chordoma
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Trauma
Aneurysm
Dural external carotid artery cavernous
sinus fistula
Sickle ceil disease
Diabetes mellitus
Syringobulbia
Infections
Sinusitis
Herpes simplex
Herpes zoster
Hepatitis A infection
Nonspecific viral infection
Tuberculosis
Whipple's disease
Leprosy
Arachnoiditis
Tricloroethylene
Hydroxystilbamidine
Amyloidosis
Spinal epidural anesthesia
Piramidal yol
Kontralateral hemiparezi
Spinotalamik demet
Kontralateral gövde ve
ekstremitelerde his kusuru
Orta serebellar pedünkül
İpsilateral tremor
Medial Longitudinal fasikül
İnternükleer oftalmopleji
İnen sempatik lifler
İpsilateral Horner sendromu
Preganglionik sinir kökleri: Subaraknoid alan
TRİGEMİNAL
NEVRALJİ ?
GASSER GANGLİONUNDA YERLEŞİK LEZYONLAR
Vasküler
Anevrizma, kollagen doku hastalıkları
Tümör
İnfeksiyon
H. Zoster, abse, petrozitis
+ Sempatik pleksus
Okülosempatik paralizi
+ IV - VI
Diplopi
+ VIII
İşitme kaybı
KAVERNÖZ SİNÜSTE YERLEŞİK LEZYONLAR
SUPERİOR ORBİTAL FİSSÜRDE YERLEŞİK
LEZYONLAR
PERİFERİK DALLARI ETKİLEYEN LEZYONLAR
İnfeksiyon
İnflamasyon; Bakteriyel-tbc-karsinomatözgranülomatöz menenjit
Travma
Kafa kaidesi fraktürü
Tümör
Paget hastalığı
Vasküler
Anevrizma, infarkt (DM)
Guillain-Barre sendromu
Facial Nerve
Temporal, Zygomatic, Buccal,
Mandibular, Cervical&Post. Auricular
internal acoustic
meatus  facial
canal 
stylomastoid
foramen
• Brachiomotor: m. of facial expr.:
stapedius,stylohyoid,
mylohyoid, post.belly digastric
• facial canal middle ear
chorda tympani
petrotympanic fissure
• Special sensory: taste, ant. 2/3
tongue: facial canal middle
ear chorda tympani
petrotympanic fissure
• Visceromotor: preganglionic
parasympathetic to submand.
ganglia (innervates submand.
&sublingual glands)
greater superficial petrosal 
pterygoid canal
pterygopalatine ganglia to
lacrimal, nasal & palatine gl.
C
B
A
Lesion at A: Ipsilateral
 paralysis of all facial
movements
 corneal reflex is lost
 sensory area to ear is
lost
Lesion at B:
A(+) impaired
 sublingual, submandibular glands’ secretions&
 taste over ant. 2/3 of the
tongue
 hyperacusis
Lesion at C: A&B(+) impaired ipsilat.lacrimation
Causes of Peripheral Facial Nerve Palsy
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Idiopathic (Bell's palsy)
Infectious:
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Herpes simplex
Herpes zoster
Otitis media
Borrelia burgdorferi
Human immunodeficiency virus
Syphilis
Infectious mononucleosis
Mastoiditis
Poliomyelitis
Meningitis
Malaria
Leprosy
Rubella
Mumps
Osteomyelitis
Cat scratch disease
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Neoplastic
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Schwannoma
Neurofibroma
Meningioma
Cholesteatoma
Parotid gland tumor
Metastasis
Carcinomatous meningitis
Leukemia
Metabolic
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Inflammatory
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Guillain-Barré syndrome
Sarcoidosis
Multiple sclerosis
Arteritis
Melkersson-Rosenthal syndrome
Behçet syndrome
Wegener's granulomatosis
Lymphomatoid granulomatosis
Kawasaki disease
Angioedema
Pseudotumor (Tolosa-Hunt syndrome)
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Amyloidosis
Idiopathic hypertrophic cranial pachymeningitis
Diabetes mellitus
Hypothyroidism
Uremia
Porphyria
Trauma: Surgical trauma to nerve
Congenital, Familial
Miscellaneous
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Pregnancy
Paget's disease
Osteopetrosis
Hypertension
Diphtheria-pertussis-tetanus
vaccination
Pontine infarction
Myasthenia gravis
Traumatic external carotid artery
aneurysm
Lumbar extradural blood patch
Vascular malformation
Pseudotumor cerebri
Ethylene glycol poisoning
Cranial Nerve VIII: Vestibulocochlear
1st neurone: bipolar cells of the gang.
cochleare 2nd neurone: multipolar
neurones of nuclei cochleares
Auditory path.
2nd neurones  corpus
trapezoideum  opposite
side  form lemniscus lat.
colliculus inferior  3rd or
4th neurone colliculus
superior cerebellum &
corpus geniculatum mediale
4th or 5th neurone: Heschl's
transverse gyrus & Wernicke's
centre of the temporal lobe
Vestibular path
FLM
nuc. ruber
nuc. vestibularis sup.
(Bechterew's)
supplies some fibres
to cerebellum
1st neurone: bipolar
cells of the ganglion
vestibulare form the N.
vestibularis on the floor
of the internal acoustic
meatus
2nd & following neurones: from
nuc.vestibularis lat. (Deiter's) to:
- formatio reticularis - motor nuclei of
nerves III, IV & VI - nuc. ruber & as the tr.
vestibulosp. into the ant. column of the
sp. cord
Cranial Nerve VIII: Vestibulocochlear
internal auditory meatus
Disease affecting hearing
Acoustic neuroma (8th n)
Presbyacusis (cochlea)
Trauma
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Wax
(ext.&middle ear)
Otitis media
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Otosclerosis
“
Disease affecting balance
Vascular diseases(b.stem)
Demyelination
“
Drugs (DPH, streptomycin)
Viral, benign conditions
Disease affecting hearing &
balance (cochlea&labyrinth)
Meniere
Cochleo-vestibular Disease
Main Symptoms
Main Signs
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Deafness
Tinnitus
Vertigo
Loss of balance
• Deafness
• Nystagmus
• Ataxia
• Positional
nystagmus
Cranial Nerve IX:
• Foramen: jugular
• Special visceromotor: Function: elevates pharynx
nucleus ambiguus  stylopharyngeus
• Gen. Sensory Components Function: general sensation of external,
middle ear & auditory tube
 geniculate ganglion spinal trigeminal nucleus
• Special Viscerosensory Component:
• Function: taste, posterior 1/3 tongue=>
inferior petrosal ganglion  rostral tractus solitarius
• Region Entered: infratemporal fossa
• Gen. Viscerosensory: Sensory receptors of ant. surface epiglottis, root
of tongue, border of soft palate, uvula, tonsil, pharynx, eustachian tube,
carotid sinus & body  caudal tractus solitarius
• Gen.Visceromotor comp.: İnf.salivary nuc.tympani n. lesser
petrosal notic ganglionauriculotemporal n.
• Function: parotid gland secretion
Microvilli of the taste receptor cells project into an opening in the epithelium,
the taste pore, where they make contact with gustatory stimuli.
These epithelial receptor cells make synaptic
contact with distal processes of cranial nerves VII, IX, or X
Nervus Vagus
Special Viscerosensory: taste in
epiglottisinf. Gang.rostral
tr. solitarius
Special visceromotor: (deglutition
phonation)
n. Ambiguuspalatal, pharynx
& larynx muscles
General viscerosensory:
post.epiglottis,larynx, trachea,
bronchi, esopagus, stomach, s.
İntestine, colon inf.
ganglioncaudal tr. solitarius
General somatosensory: : auricle,
ext. auditory meatussup.
ganglionspinal trigeminal nuc
General Visceromotor: dorsal
motor nucleus preganglionic
parasympathetic to abdomen &
thorax cardiac depression, visc.
mov., secretion
Primary afferents in the IX and X cranial
nerves project to the NTS
vagal afferents
Right & Left
recurrent
laryngeal
nerves
Selected Causes of Vagus Nerve Dysfunction
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Lateral medullary syndrome
Hyperextension
injury of upper cervical spine
Chronic lead poisoning
Radiation therapy to head and neck
Glomus vagale tumor
Neuroma
Schwannoma presenting as cerebellopontine angle mass
Nasopharyngeal diphtheria
Viral or postviral mononeuritis
Herpes simplex
Cytomegalovirus
Herpes zoster
Multiple system atrophy
Superior laryngeal neuralgia
Cranial Nerve XI: Spinal Accessory
• Brachiomotor Comp:
Foramen:  exits by
jugular;  enters by
foramen magnum ant.
horn cells C1-C5
Target: trapezius,
sternokleidomastoid
Function: head & shoulder
movement
• Spc.Visceromotor Comp.:
Caudal nuc. ambiguus
vagus muscles of
larynx Function: phonation
Symptoms of the
11th n.
involvement
Torticollis
(dystonia)
Asymmetric
shoulders
Impaired arm
elevation
Cranial Nerve XII: Hypoglossal
• Foramen:
hypoglossal canal
• Region Entered:
neck
• Components:
somatomotor
• Target, Function: all
tongue muscles,
except palatoglossus
Infranuclear
paralysis of the
right trigeminal,
facial, and
hypoglossal nerves,
showing deviation
of the mandible and
tongue to the right
12th n. palsy:
Asymmetry
Deviation
Atrophy
Fasciculations
10th nerve
Common Condition Affecting
9th, 10th & 12th Nerve Function
 Motor neuron disease
 Cerebrovascular disease
 Syringobulbia
 Erosive tm of the skull base
 Guillain-Barré syndrome
 Recurrent laryngeal nerve palsy
 Myastenia gravis
Bulbar palsy
•Dysartria
•Dysphagia
•Dysphonia
•Aspiration