Transcript 18. Cranial Nerves

Cranial Nerves
Cranial Nerves
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Special Sense Nerves
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I,II,VIII
Somatic Motor Nerves
Eye—III,IV,VI
Tongue--XII
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“Rest of body” nerves
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IX,X,XI
Face and jaws
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VII, V
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
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Head I: Skull—a framework to hang on
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Overall organization of skull
Base of the skull—the hard part
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Developmental view
Cranial nerves out (to “targets”)
Head II: Throat targets
Head III: Special Sense targets
Head IV: Cranial nerves in depth
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
Nerve “targets” in head
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SENSORY
Special
Smell
Vision
Hearing
General
skin
teeth
eye
tongue
oral cavity
nasal cavity
middle ear
throat
meninges
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
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MOTOR
Muscles
Glands
eyes
salivary
extrinsic sweat
intrinsic lacrimal
jaws
mucous
facial expression
larynx
tongue
throat
ear
Base of the skull—cranial nerves out
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Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
Ethmoid (olfactory)
I. Olfactory
Sphenoid (optic)
II. Optic
III. Oculomotor
IV. Trochlear
VI. Abducens
Temporal (otic)
VII. Acoustic/Auditory/
Vestibulocochlear
Face/Jaws
V. Trigeminal
VII. Facial
Throat (rest of body)
IX Glossopharyngeal
X. Vagus
XI. Spinal Accessory
XII. Hypoglosal
Cranial nerves
Cranial nerves
Special Sense Nerves
NERVE
TARGET
EXIT FROM
CRANIAL CAVITY
I. Olfactory
Olfactory
epithelium
Cribiform plate
(ethmoid)
II. Optic
Retina
Optic canal
(sphenoid)
VIII. Auditory Inner ear
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
Internal auditory
meatus (temporal)
M&M, Table 14.3
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
Somatic Motor Nerves
(eye muscles and tongue)
NERVE
TARGET
IV. Trochlear
Superior oblique m.
(with trochlea)
VI. Abducens
Lateral rectus
III. Oculomotor
•Sup.,med.,inf.rectus
(Also parasympathetic
• Inferior Oblique
to ciliary mm, constrictor
•Levator palpebrae
pupillae)
superioris
XII. Hypoglossal
Intrinsic, extrinsic
mm. of tongue
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
EXIT CR. CAVITY
Sup. Orbital fissure
(sphenoid)
“
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Hypoglossal canal
(occipital)
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
Cranial nerves
Cranial nerves
“Rest of body” nerves
(all exit from jugular foramen)
NERVE
TARGET
 Somatic motor to larynx/pharynx
 Parasympathetic to most of gut
 Taste to back posterior pharynx
XI: (Spinal)  Motor to traps,
Accesory
sternocleidomastoid
IX: Glosso-  Sensory to carotid body/sinus
pharyngeal  Taste to posterior tongue
 Sensory to ear opening/middle
ear
 Parotid salivary gland
X: Vagus
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
VII: Facial Nerve
(exits cranial cavity with VIII--internal auditory meatus)
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Facial muscles (five branches fan out over face from
stylomastoid foramen)
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“chorda tympani” (crosses interior ear drum to join V3 )
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Temporal
Zygomatic
Buccal
Mandibular
Cervical
Taste to anterior 2/3 of tongue
Submandibular, sublingual salivary glands
Lacrimal glands
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
V: Trigeminal (3 nerves in 1!)
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V1. Ophthalmic
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V2. Maxillary
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Exits with eye muscle group (superior orbital fissure, through orbit to
superior orbital notch/foramina)
Sensory to forehead, nasal cavity
Exits foramen rotundum through wall of maxillary sinus to inferior
orbital foramina)
Sensory to cheek, upper lip, teeth, nasal cavity
V3. Mandibular
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Exits foramen ovale to mandibular foramen to mental foramen
Motor to jaw muscles--Masseter, temporalis, pterygoids, digastric
Sensory to chin
Sensory to tongue
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
Cranial Nerves
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I: Olfactory
II: Optic
III: Oculomotor
IV: Trochlear
V: Trigeminal
VI: Abducens
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VII: Facial
VIII:Vestibulocochlear
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Acoustic
IX: Glossopharyngeal
X: Vagus
XI: Accessory
XII: Hypoglossal
http://www.gwc.maricopa.edu/class/bio201/cn/cranial.htm
Mnemonic
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On
Old
Olympus’
Tower
Top
A
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Fin
And
German
Viewed
A
Hop
MNEMONIC
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OLFACTORY
OPTIC
OCULOMOTOR
TROCHLEAR
TRIGEMINAL
ABDUCENS
FACIAL
VESTIBULOCOCHLEAR
GLOSSOPHARYNGEAL
VAGUS
ACCESSORY
HYPOGLOSSAL
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OH
ONCE
ONE
TAKES
THE
ANATOMY
FINAL
VERY
GOOD
VACATION
A-HEAD
CN I: OLFACTORY
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Cranial nerve I
Function:
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smell
Clinical test for
damage:
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determine whether
a person can smell
something aromatic
CN II: OPTIC
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Cranial nerve II
Function:
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Clinical test for
damage:
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vision
tests peripheral vision
and visual acuity
Effects of damage:
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blindness in part or all
of the visual field
CNIII: OCULOMOTOR
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Cranial nerve III
Function:
 eye movements, opening of
eyelid, constriction of pupil,
focusing, proprioception
Clinical tests for injury:
 differences in pupil size;
pupillary response to light; eye
tracking
Effects of damage
 dropping eyelid, dilated pupil,
double vision
CNIV: TROCHLEAR
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Cranial nerve IV
Function: eye movements
and proprioception
Clinical test for injury: ability
to rotate eye inferolaterally
Effects of damage – double
vision, patient tilts head
toward affected side
CN V: TRIGEMINAL
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Cranial nerve V
Function: sensory nerve of the
face
Clinical test for injury:
 corneal reflex; sense of
touch, pain, and
temperature; clench teeth;
move mandible side to side
Effects of damage:
 loss of sensation and
impaired chewing
CN VI: ABDUCENS AND CN
VII: FACIAL
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Cranial Nerve VI
Function: Eye
movements
Clinical test: lateral eye
movement
Effects of damage:
inability to rotate eye
laterally; at rest – eye
rotates medially
because of action of
antagonistic muscles
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Cranial Nerve VII
Function: facial
expression; sense of
taste
Clinical test: motor
functions – close eyes,
smile, whistle, frown,
raise eyebrows; taste
Effects of damage:
inability to control
facial muscles;
distorted sense of taste
CN VIII:
VESTIBULOCOCHLEAR
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Cranial Nerve VIII
Function: hearing and equilibrium
Clinical tests: test hearing, balance, and
ability to walk a straight line
Effects of damage: deafness, dizziness,
nausea, loss of balance, and nystagmus
CN IX: GLOSSOPHARANGEAL
AND CN X: VAGUS
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Cranial Nerve IX
Function: swallowing,
salivation, gagging; touch,
pressure, taste, and pain
sensations from tongue,
pharynx, and outer ear
Clinical tests: gag reflex,
swallowing, and coughing
Effects of damage:
difficulty swallowing
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Cranial Nerve X
Function: swallowing; taste;
speech; respiratory, CV, and
GI regulation; sensations of
hunger, fullness, and
intestinal discomfort
Clinical tests: test with
cranial nerve IX
Effects of damage:
hoarseness or loss of voice;
impaired swallowing and GI
motility
CN XI: ACCESSORY AND
CN XII: HYPOGLOSSAL
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Cranial Nerve XI
Function: swallowing; head,
neck, and shoulder
movements
Clinical tests: rotate head
and shrug shoulders against
resistance
Effects of damage: impaired
movement of head, neck,
and shoulders; paralysis of
sternocleidomastoid
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Cranial Nerve XII
Function: tongue movements
of speech, food
manipulation, and
swallowing
Clinical test: tongue function
Effects of damage: difficulty
in speech and swallowing;
atrophy of tongue; inability
to stick out (protrude)
tongue