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Cranial Nerves
Sanjaya Adikari
Department of Anatomy
12 pairs of cranial nerves
III to XII attached to
brain stem
Their cell bodies form
nuclei in the brain stem
First cell body of sensory
nerves lie out side CNS
(form ganglia)
Summary of cranial nerves
Aspects to study
1.
Position of nucleus
2.
Emerging point from brain stem
3.
Intracranial course
4.
Point of exit from the cranial cavity
5.
Extracranial course
6.
Distribution
Few terms: Somatic, branchial and visceral
Branchial
Branchial (Pharyngeal) Arches
ectoderm
endoderm
• Core of mesodermal
tissue covered by
ectoderm and
endoderm
• Each of the arch will
have its own
bone/cartilage, muscles,
nerve and artery
Mandibular branch of
trigeminal nerve (V)
Facial nerve
(VII)
Premaxilla, maxilla, zygomatic
bone, part of temporal bone and
mandible
Glossopharyngeal nerve
(IX)
Superior laryngeal branch
of vagus nerve (X)
Recurrent laryngeal branch
of vagus nerve
(X)
Visceral
• In relation to internal organs
– Heart
– Lung
– Intestines
………………
……………..
Few hints
Nerve A
Nerve B
Posterior
Somatic sensory
Visceral sensory
Sensory
Motor
Visceral motor
Somatic motor
Spinal cord (thoracic or lumbar)
Posterior horn
Lateral horn
Sensory
Motor
Anterior horn
Brain stem
SM
BM
VM
VS
GSS
SS
SpS
Types of sensations
General Visceral sensory
Visceral sensory
pain, temperature, touch, viration
position sense
Special Visceral sensory
taste
General Somatic sensory
Somatic sensory
pain, temperature, touch, vibration
position sense
Special Somatic sensory
hearing
SM
III
IV
VI
XII
V
VII
IX
X
XI
III
VII
IX
X
BM
VM
VS
GSS
SS
VII
IX
X
V
VII
IX
X
VIII
Functional components of cranial nerves
III
IV
Somatic Motor
Muscles of the orbit
(III, IV, VI)
Muscles of tongue
(XII)
VI
XII
Branchial Motor
Muscles of mastication (V)
Facial muscles (VII)
Pharyngeal and laryngeal
muscles (Nucleus ambiguus
via IX, X, XI nerves)
Visceral Motor
Edinger Westphal nucleus
(accessory oculomotor)
Salivary nuclei (NI part of VII, IX)
Dorsal motor nucleus of vagus
(for cardiac muscles, smooth
muscles of alimentary tract)
Sensory
Consists of single nuclei for visceral
and somatic sensory
Visceral sensory with taste
Nucleus of tractus solitarious which
receives taste fibres from the tongue
through VII, IX
and sensory from heart, lungs and
other viscera through X
General somatic sensory
Sensory nucleus of trigeminal
nerve extending from the
midbrain to the cervical spinal
cord
Special somatic sensory
Hearing via VIII
(vestibulocochlear nerve)
BM
SM VM
III
IV
VI
XII
III
VII
IX
X
V
VII
IX
X
XI
VS
GSS
SS
VII
IX
X
V
VII
IX
X
VIII
Intracranial course and exit
Sanjaya Adikari
Department of Anatomy
Optic canal
(II)
Superior orbital fissure
(III, IV, V1, VI)
Foramen rotundum
(V2)
Foramen ovale
(V3)
Foramen spinosum
Foramen lacerum
Internal acoustic meatus
(VII, VIII)
Jugular foramen
(IX, X, XI)
Hypoglossal canal
(XII)
Olfactory Nerve (I)
Olfactory tract
Olfactory bulb
Anterior perforated
substance
Uncus
Nerve filaments
Cribriform plate of
ethmoid bone
Bypass thalamus and goes directly into
the taste area
Optic Nerve (II)
T
N
T
Optic Nerve (II)
Optic nerve
Optic chiasma
Optic tract
Optic
radiation
Pretectal nucleus
(pupillary reflexes)
Internal
capsule
Lateral geniculate body
of thalamus
Superior colliculus
(body reflexes)
Oculomotor Nerve (III)
Somatic motor nucleus
Visceral motor nucleus
(Edinger westphal nucleus)
Nerve emerges from ventral
aspect of midbrain
travel’s in the lateral wall of the
cavernous sinus
Oculomotor Nerve… cont.
Levator palpabrae
superioris
Sympathetic from
Internal carotid plexus
Dilator pupillae
Superior division
Superior rectus
Inferior division
Medial rectus, inferior
rectus, inferior oblique
Parasympathetic from
EW nucleus
Ciliary muscle
Sphincter pupillae
Ciliary ganglion
Trochlear Nerve (IV)
Somatic motor nucleus
Emerges from the dorsal aspect of
midbrain
Travels in the lateral wall of the
cavernous sinus
Supplies the superior oblique muscle
Abducens Nerve (VI)
Somatic motor nucleus
Nucleus lies in lower pons near
midline
Emerge between pons and pyramid
of medulla
Travels through the cavernous sinus
Supply the lateral rectus muscle
Oculomotor N (III)
Ventral
midbrain
Lateral wall
Cavernous S
Divide
Sup. & Inf.
divisions
Lateral wall
Cavernous S
Superior
orbital
fissure
Trochlear N (IV)
Dorsal
midbrain
Abducent N (VI)
Between
Pons & pyramid
of medulla
within
Cavernous S
Superior
orbital
fissure
Sup/infrao
rbital
fissure
Cavernous sinus
1- Oculomotor N
2- Trochlear N
3- Abducent N
4- Ophthalmic branch of TN
5- Maxillary branch of TN
6- Sympathetic plexus of N
7- Internal carotid A
8- Pituitary gland
LR6(SO4)3
Trigeminal nerve (V)
Branchial motor nucleus
Somatic sensory nucleus
Emerge from the ventral aspect of pons
Sensory and motor roots emerge
separately
Trigeminal nerve… cont.
Somatic
sensory
nucleus
Trigeminal ganglion
Cell bodies of 1st order
SA fibres
Ophthalmic
division
Maxillary
division
Lat. Wall of
cavernous
sinous
Mandibular
division
Branchial
motor
nucleus
Foramen ovale
Mandibular
nerve
(mixed)
Facial Nerve (VII)
Branchial motor nucleus
Visceral motor nucleus
(Superior salivary nucleus)
Taste sensory nucleus
(Tractus solitarius)
Main facial nerve and the
nervous intermedius parts
emerge from the
cerebellopontine angle
Facial Nerve…cont.
Internal acoustic
meatus
Geniculate ganglion
(taste 1st order cell bodies)
Branchial motor
nucleus
Sup. salivary
nucleus
Nucleus of
Tractus
solitarious
Chorda tympani
nerve
Nervous
intermedius
Taste from
anterior tongue
Ear drum
Greater petrosal
nerve
Nerve to
stapedius
Stylomastoid
foramen
Pure branchial motor facial nerve
VE to submandibular gland
and glands on the mouth floor Supply muscles of facial
expression
Vestibulocochlear Nerve (VIII)
Internal acoustic
meatus
Spiral ganglion of cochlea
Cochlear
nuclei
in pons
Cochlear nerve
Hair cells of spiral
organ
Vestibular ganglion
Vestibular
nuclei
in medulla
Cerebellopontine
angle
Vestibular nerve
Hair cells of utricle,
saccule and semilunar
canals
Glossopharyngeal Nerve (IX)
Branchial motor nucleus (Nucleus ambiguus)
supplies stylopharyngeus muscle
Parasympathetic nucleus (Inferior salivary
nucleus)
supplies parotid gland
Sensory nuclei
GSS from posterior tongue goes to sensory
nucleus of trigeminal nerve
Taste from the posterior tongue goes to the
tractus solitarius
VS from baroreceptors go to nucleus of tractus
solitarius
Vagus Nerve (X)
Branchial motor nucleus (Nucleus ambiguus)
supplies pharyngeal constrictors
Visceral motor nucleus (Dorsal motor nucleus
of vagus)
supplies muscles of heart, bronchi, oesophagus,
stomach and intestines
Visceral sensory nucleus
VS from larynx, heart, lung… goes to nucleus of
tractus solitarius
GSS goes to sensory nucleus of trigeminal nerve
Accessory Nerve (XI)
Branchial motor nerve
Cranial root
From nucleus ambiguus
Fibres in the cranial root join the vagus
nerve
Somatic motor nerve
Spinal root
Anterior horn cells of upper 5-6
cervical spinal segments
Fibres in the spinal root supply
sternocleidomastoid and trapezius
muscles
Hypoglossal Nerve (XII)
Somatic motor nerve
Leaves cranial cavity through the hypoglossal canal
Supplies all muscles (intrinsic and extrinsic) of tongue except
palatoglossus