Neuroanatomy of Cranial
Nerves
Overview
CNS
Brain and Spinal Cord
Information processing/Interneurons
Sensory/Afferent
PNS
Motor/Efferent
Nerves
•General Sensory
(Somatic and Visceral)
•Special Sensory
RECEPTORS
•Somatic Motor
•Visceral Motor (ANS)
EFFECTORS
Functional Components of Nerves
• General sensory
– Somatic sensory (GSA)
– Visceral sensory (GVA)
• Special sensory (SSA, SVA)
• Somatic motor (GSE)
– Branchial motor (SVE) to skeletal muscles
derived from branchial arches
– Somatic motor (GSE) to skeletal muscles
derived from other sources
• Visceral motor (GVE) to smooth muscle
and glands
Cranial Nerves
• Carry 1-4 functional
components
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–
General sensory
Special sensory
Somatic motor
Visceral motor
What to Know About Cranial Nerves
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Name and Number
Origin from brain
Functional components
Location of cell bodies
– Nucleus
– Ganglion
• Foramen of exit from cranial cavity
• Distribution: branches, targets, and
functions
• Testing and lesions
Cell Bodies of Cranial Nerves
• General sensory neurons – in a sensory
ganglion (no synapses, pseudounipolar)
• Special sensory neurons – in a sensory
ganglion or in the sensory organ
• Somatic motor neurons – in a nucleus
• Visceral motor neurons–
– Preganglionic – in a nucleus
– Postganglionic – in an autonomic ganglion
(synapses)
General Sensory
Pathways
• Neurons
– Primary/peripheral
– Secondary
– Tertiary (cell body in
thalamus)
L 1-23
Voluntary Motor
Pathway
• AKA Pyramidal system
• Upper motor neurons
• Lower motor neurons
L Fig 1-23
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I Olfactory
II Optic
III Oculomotor
IV Trochlear
V Trigeminal
VI Abducens
VII Facial
VIII Vestibulocochlear
IX Glossopharyngeal
X Vagus
XI Spinal accessory
XII Hypoglossal
Special Sensory
• CN I – Olfactory (olfaction)
• CN II – Optic (vision)
• CN VIII – Vestibulocochlear (hearing,
equilibrium)
• CN’s VII, IX, X - taste
General Sensory
• CN V – Trigeminal
– V1
– V2
– V3
– Sensory neuron cell bodies in trigeminal
ganglion
• Other cranial nerves with general sensory
fibers – CN’s VII, IX, and X
Somatic Motor
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CN’s III, IV and VI
CN XI
CN XII
CN V3 (arch I)
CN VII (arch II)
CN IX (arch III)
CN X (arches IV, VI)
ocular muscles
SCM and trapezius
tongue muscles
muscles of mastication, etc.
m’s of facial expression, etc.
stylopharyngeus
m’s of soft palate, pharynx,
and larynx
Visceral Motor
(Parasympathetic)
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CN’s III, VII, IX, X
Ganglia:
Targets:
Postganglionic
parasympathetics tend to
follow branches of the
trigeminal nerve.
L 1-25
Sympathetics
to the Head
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Origin:
Ganglia:
Targets:
Postganglionic
sympathetics follow
branches of carotid
arteries (in a
perivascular plexus)
L 1-26
CN’s Carrying All Four
Functional Components
• CN VII
• CN IX
• CN X
Branches of Cranial Nerves May
Serve Different Functions
V3
Netter Plate 42
References
• Regional anatomy – Liebgott Chapter 7
• Systemic anatomy – Liebgott Chapter 8
• Images – Netter Plates 112-125