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Cranial Nerves
I through XII
Olfactory Nerve I
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Sense of smell
Damage causes impaired sense of smell
Optic Nerve II
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Provides vision
Damage causes blindness in visual field
Oculomotor Nerve III
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Somatic and Autonomic motor function
Eye movement (Superior, inferior, medial rectus muscles and inferior
oblique muscle), opening of eyelid (levator palpebrae superioris),
constriction of pupil (circular muscle), focusing (ciliary muscle and
accomodation)
Damage causes drooping eyelid, dilated pupil, double vision, difficulty
focusing and inability to move eye in certain directions
Trochlear Nerve IV
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Eye movement (superior oblique muscle)
Damage causes double vision and inability to
rotate eye
Trigeminal Nerve V
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Ophthalmic branch – sensations from nasal cavity, skin of forehead,
upper eyelid, eyebrow, nose
Maxillary branch – sensations from lower eyelid, upper lips and
gums, teeth of the maxilla, cheek, nose, palate, pharynx
Mandibular branch – sensations from teeth of the mandible, lower
gums and lips, palate, tongue. Motor function of temporalis and
masseter muscles.
Damage produces loss of sensation and impaired chewing
Abducens Nerve VI
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Provides eye movement (lateral rectus m.)
Damage results in inability to rotate eye
laterally and at rest eye rotates medially
Facial Nerve VII
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Somatic Motor - facial expressions
Autonomic Motor - salivary and lacrimal glands, mucous
membranes of nasal and palatine mucosa
Special Sensory - taste on anterior 2/3’s of tongue
Damage produces sagging facial muscles and disturbed
sense of taste (no sweet and salty)
Vestibulocochlear Nerve VIII
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Special Sensory
Provides hearing (cochlear branch) and sense of
balance (vestibular branch)
Damage produces deafness, dizziness, nausea,
loss of balance
Glossopharyngeal Nerve IX
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Somatic motor – Swallowing and voice production via pharyngeal
muscles
Autonomic motor - salivation, gagging, control of BP and respiration
Sensations from posterior 1/3 of tongue including taste
Damage results in loss of bitter and sour taste and impaired swallowing,
blood pressure anomalies (with CN X).
Vagus Nerve X
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Sensations from skin at back of ear,
external acoustic meatus, part of
tympanic membrane, larynx, trachea,
espophagus, thoracic and abdominal
viscera
Special sensory – taste from
epiglottis and pharynx
Somatic motor – Swallowing and
voice production via pharyngeal
muscles
Autonomic motor – smooth muscle of
abdominal viscera, visceral glands
secretions, relaxation of airways, and
normal or decreased heart rate.
Damage causes hoarseness or loss
of voice, impaired swallowing, GI
dysfunction, blood pressure
anomalies (with CN IX), fatal if both
are cut
Accessory Nerve XI
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Swallowing, head, neck and shoulder movement via trapezius
and sternocleidomastoid and pharyngeal muscles
Damage causes impaired head, neck, shoulder movement
Hypoglossal Nerve XII
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Tongue movements for speech, food manipulation
and swallowing
If both are damaged – can’t protrude tongue
If one side is damaged – tongue deviates towards
injured side