Transcript Cranial Nerve

The Cranial Nerves: A Review
Dr. Ann Gathers
Department of Biological Sciences
The University of Tennessee at Martin
Health Science Teacher Education Symposium
Nashville, Tennessee
October 1-2, 2007
Athletes and Cranial Nerves
• Contact sports have the highest incidence of
nerve injuries.
• In the US, approximately 1/3 of diagnosed
nerve injuries were related to football
trauma.
• Others included wrestling, weight-lifting, and
baseball and softball (regional differences)
• 12 Pairs of Peripheral Nerves
• Originate in or near the brain
• Sensory, Motor, and Mixed
• Voluntary, Involuntary, and Mixed
Olfactory (I)
Optic (II)
Oculomotor (III)
VENTRAL
VIEW
Trochlear (IV)
Trigeminal (V)
Facial (VII)
Abducens (VI)
Glossopharyngeal (IX)
Vagus (X)
Hypoglossal (XII)
Auditory (VIII)
Spinal
Accessory (XI)
Facial
Oculomotor
Optic
Trochlear
Olfactory
Glossopharyngeal
Vagus & Auditory
Trigeminal
Abducens
Glossopharyngeal
Hypoglossal Spinal Accessory
Oh
Once
One
Takes
The
Anatomy
Final
Very
Good
Vacations
Seem
Heavenly
Olfactory (I)
Optic (II)
Oculomotor (III)
Trochlear (IV)
Trigeminal (V)
Abducens (VI)
Facial (VII)
Vestibulocochlear (VIII)
Glossopharyngeal (IX)
Vagus (X)
Spinal accessory (XI)
Hypoglossal (XII)
Functions
Olfactory (I)
• Provides sense of smell
• Damage causes impaired sense of smell
Optic (II)
Optic (II)
• Provides vision
• Damage causes blindness in visual field
Oculomotor (III)
• Some eye movement, opening of eyelid (innervates
all extraocular muscles except lateral rectus &
superior oblique)
• Constriction of pupil (parasympathetic)
• Focusing
• Damage: drooping eyelid (ptosis), dilated pupil,
double vision (diplopia), difficulty focusing & inability
to move eye in certain directions
Trochlear (IV)
• Provides eye movement
• Damage causes double vision (diplopia) &
inability to rotate eye downward and outward
Trigeminal (V)
Trigeminal (V)
Three Branches:
1.Opthalmic
2.Maxillary
3.Mandibular
• Main sensory nerve to face (touch, pain and
temperature) and muscles of mastication
• Damage produces loss of sensation &
impaired chewing
Abducens (VI)
• Provides eye movement (lateral rectus)
• Damage results in inability to rotate eye
laterally & at rest eye rotates medially
(strabismus = cross-eyed)
Facial (VII)
• Facial expressions
• Taste on anterior 2/3’s of tongue,
• Salivary glands and tear, nasal & palatine glands
• Damage: sagging facial muscles (ptosis and corner
of mouth droops) and disturbed taste (no sweet &
salty sensations)
i.e. Unilateral sagging facial muscles
Bell’s Palsy
Auditory/
Vestibulocochlear (VIII)
• Provides hearing & sense of balance
• Damage produces deafness, dizziness,
nausea, loss of balance & nystagmus
Glossopharyngeal (IX)
• Provides control over swallowing, salivation
(parotid), gagging, sensations from posterior 1/3 of
tongue, control of BP and respiration (receptors in
carotid)
• Damage results in loss of bitter & sour taste &
impaired swallowing (dysphagia)
Vagus (X)
Vagus (X)
• Provides swallowing, speech, regulation of
viscera (somatic and visceral)
• Damage causes hoarseness or loss of voice,
impaired swallowing (dysphagia)
i.e. Neurocardiogenic Syncope
relatively new diagnosis
fainting spells
Spinal Accessory (XI)
• Swallowing, head, neck & shoulder
movement
• Damage: impaired head, neck & shoulder
movement, head turns towards injured side
Hypoglossal (XII)
Hypoglossal (XII)
• Tongue movements of speech , food
manipulation & swallowing
• Damage: inability to protrude tongue if
bilateral damage
• deviation towards injured side & ipsilateral
atrophy if unilateral damage
i.e. Dysarthria
poor articulation
Thank You