The Cranial Nerves: A Review

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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
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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)

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• 12 Pairs of Peripheral Nerves
• Originate in or near the brain
• Sensory, Motor, and Mixed
• Voluntary, Involuntary, and Mixed

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Olfactory (I)
Optic (II)
Oculomotor (III)
VENTRAL VIEW
Trochlear (IV)
Trigeminal (V)
Facial (VII)
Abducens (VI)
Auditory (VIII)
Glosso- pharyngeal (IX)
Spinal Accessory (XI)
Vagus (X)
Hypoglossal (XII)
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Oculomotor
Facial
Optic
Trochlear
Olfactory
Glossopharyngeal
Vagus Glossopharyngeal
Auditory
Trigeminal
Abducens
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Spinal Accessory
Hypoglossal
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Oh Olfactory (I) Once Optic (II) One
Oculomotor (III) Takes Trochlear
(IV) The Trigeminal (V) Anatomy Abducens
(VI) Final Facial (VII) Very Vestibulocochlear
(VIII) Good Glossopharyngeal (IX) Vacations Vagus
(X) Seem Spinal accessory (XI) Heavenly Hypoglo
ssal (XII)
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Functions
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Olfactory (I)

• Provides sense of smell
• Damage causes impaired sense of smell

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Optic (II)
Optic (II)

• Provides vision
• Damage causes blindness in visual field

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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

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Trochlear (IV)

• Provides eye movement
• Damage causes double vision (diplopia)
  inability to rotate eye downward and outward

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Trigeminal (V)
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Trigeminal (V)

• Three Branches
• Opthalmic
• Maxillary
• Mandibular

• Main sensory nerve to face (touch, pain and
  temperature) and muscles of mastication
• Damage produces loss of sensation impaired
  chewing

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Abducens (VI)

• Provides eye movement (lateral rectus)
• Damage results in inability to rotate eye
  laterally at rest eye rotates medially
  (strabismus cross-eyed)

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Facial (VII)

• Facial expressions
• Taste on anterior 2/3s 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
• Bells Palsy

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Auditory/ Vestibulocochlear (VIII)

• Provides hearing sense of balance
• Damage produces deafness, dizziness, nausea, loss
  of balance nystagmus

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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)

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Vagus (X)
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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

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Spinal Accessory (XI)

• Swallowing, head, neck shoulder movement
• Damage impaired head, neck shoulder movement,
  head turns towards injured side

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Hypoglossal (XII)
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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

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Thank You