Download Cranial Nerves

Cranial Nerves
Clinical
Assessment
The “FACE” of
Cranial Nerves
I Olfactory
II Optic
III Oculomotor
IV Trochlear
V Trigeminal
VI Abducens
VII Facial
VIII Acoustic
IX Glossopharyngeal
X Vagus
XI Spinal Accessory
Xii Hypoglossal
Cranial Nerves
Cranial Nerves
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When assessing the cranial nerves, there are
4 items the examiner must know:
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Function
Name & Location of Primary Nuclei
Testing
Signs of Dysfunction
Cranial Nerves
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CN I – Olfactory Nerve
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Function: special sensory
Name & Location of 1o Nuclei: cribriform plate
Testing:
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Use 2-3 vials of familiar odors
Test one nostril at a time with patient’s eyes closed
Use least irritating scent first and allow the patient to rest in
between vials
Signs of Dysfunction: anosmia
Cranial Nerves
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CN II – Optic Nerve
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Function: special sensory
Name & Location of 1o Nuclei: retina
Testing:
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Snellen Eye chart
Fundus Exam
Visual fields via confrontation
Pupillary Light reflex
Signs of Dysfunction
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Blindness
Loss of pupillary constriction (sensory)
Cranial Nerves
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CN III – Occulomotor Nerve
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Function: somatic & visceral motor
Name & Location of 1o Nuclei:
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Testing:
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Somatic Motor Nucleus: EOM
Visceral Motor: pupillary constriction & accommodation
Six Cardinal Fields of Gaze
Pupillary Light reflex: (motor)
Accommodation
Signs of Dysfunction:
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Eye turned down & out w/ ptosis
Mydriasis, Loss of accommodation, Diplopia
Cranial Nerves
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CN IV – Trochlear Nerve
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Function: somatic motor
Name & Location of 1o Nuclei
Testing:
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Six Cardinal Fields of Gaze
Signs of Dysfunction:
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Vertical diplopia
Excycodeviation of the eye
Cranial Nerves
CN V – Trigeminal Nerve
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Function:
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Branchial motor – mastication
General Sensory – sensory to the face
Name & Location of 1o Nuclei –
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Motor
Sensory
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Mesencephalic Nucleus: proprioception
Pontine Trigeminal Nucleus: touch
Nucleus of Spinal Tract (spinal trigeminal tract): pain & temp
Cranial Nerves
CN V – Trigeminal Nerve
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Testing:
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Sharp & light touch over the three divisions
Corneal Blink Reflex (sensory)
Clinch teeth & Jaw Jerk
Signs of Dysfunction:
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Weakness
Hemianesthesia
Absent Corneal Blink Reflex
Cranial Nerves
CN VI – Abducens Nerve
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Function: somatic motor
Name & Location of 1o Nuclei
Testing:
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Six Cardinal Fields of Gaze
Signs of Dysfunction:
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Horizontal diplopia
Medial deviation of the eye
Cranial Nerves
CN VII – Facial Nerve
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Function:
Branchial motor – facial muscles
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Visceral motor – glandular fcn
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General Sensory – skin of the auricle
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Special Sensory - taste
Name & Location of 1o Nuclei:
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Facial Motor Nucleus
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Superior Salivatory Nucleus
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Nucleus of Spinal Tract
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Nucleus Solitarius
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Cranial Nerves
CN VII – Facial Nerve
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Testing:
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Branchial motor component: facial expression
Special Sensory: taste to the anterior 2/3 of tongue
Signs of Dysfunction:
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Hemiparesis
Dry eye
Lagophthalmos
Dry mouth
Loss of taste
Cranial Nerves
CN VIII – Acoustic
(Vestibulocochlear) Nerve
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Function: special sensory
Name & Location of 1o Nuclei:
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Vestibular Nucleus
Dorsal & Ventral Cochlear Nucleus
Testing: hearing tests: Rinne, Weber, Audiology
Signs of Dysfunction:
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Vertigo
Nystagmus
Disequilibrium
Sensorineural deafness
Cranial Nerves
CN IX – Glossopharyngeal Nerve
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Function:
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Branchial Motor – elevation of pharynx during swallowing &
speech
Visceral Motor – parotid gland fcn
Visceral Sensory – communication between carotid body &
sinus
General Sensory - tongue
Special Sensory - taste
Cranial Nerves
CN IX – Glossopharyngeal Nerve
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Name & Location of 1o Nuclei:
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Nucleus Ambiguous
Inferior Salivatory Nucleus
Nucleus Solitarius
Nucleus of Spinal Tract
Nucleus Solitarius
Testing:
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Branchial Motor: swallowing
General Sensory: gag reflex
Special sensory: taste of posterior 1/3 of tongue
Cranial Nerves
CN IX – Glossopharyngeal Nerve
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Signs of Dysfunction
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Dysphagia
Dry mouth
Loss of taste
Loss of gag reflex
TYPICALLY, IX and X
are tested together
Cranial Nerves
CN X – Vagus Nerve
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Function:
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Branchial Motor – deglutition & phonation
Visceral Motor – smooth muscles of the thoracic & abdominal
viscera
Visceral Sensory – thoracic & abdominal viscera
General Sensory – external ear
TYPICALLY, IX and X
are tested together
Cranial Nerves
CN X – Vagus Nerve
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Name & Location of 1o Nuclei:
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Testing:
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Nucleus Ambiguous
Dorsal Vagal Nucleus
Nucleus Solitarius
Nucleus of Spinal Tract
Branchial motor: swallowing, gag reflex, soft palate elevation with uvula
remaining while saying “Ah”
Signs of Dysfunction:
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Dyspagia
Hoarsness
Uvula deviation
Cranial Nerves
CN XI – Spinal Accessory Nerve
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Function: somatic motor
Name & Location of 1o Nuclei
Testing: Resisted shoulder elevation & head rotation
Signs of Dysfunction:
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Atrophy & Weakness
Fasciculations
Neck or shoulder deviation
Cranial Nerves
CN XII – Hypoglossal Nerve
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Function: somatic motor
Name & Location of 1o Nuclei
Testing:
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Stick out tongue
Press tongue against check while palpating to test muscle
strength
Articulation of hard consonants: ‘L’, ‘T’, ‘D’, & ‘N’
Signs of Dysfunction:
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Atrophy & Weakness
Deviation
Dysarthria