Dr. Michael P. Gillespie
 Between the brain and spinal cord.
 3 regions.
 Medulla oblongata.
 Pons.
 Midbrain.
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 A continuation of the spinal cord.
 Sensory (ascending) tracts and motor (descending)
tracts travel through the white matter of the medulla.
 Many nerves decussate (cross over) in the medulla.
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 Cardiovascular center regulates the heartbeat and the
diameter of the blood vessels.
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 The medullary rhythmicity area adjusts the rhythm of
the breathing and controls reflexes for vomiting,
coughing, and sneezing.
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 The nuclei for the following cranial nerves reside in
the medulla:
 VIII (vestibulocochlear).
 IX (glossopharyngeal).
 X (vagus).
 XI (accessory).
 XII (hypoglossal).
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 Pneumotaxic area and apneustic area regulate
breathing.
 Nuclei for cranial nerves V (trigeminal), VI
(abducens), and VII (facial).
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 The midbrain or mesencephalon contains the
superior colliculi (visual actvities) and inferior
colliculi (auditory pathways).
 The midbrain contains the substantia nigra which
release dopamine to help control subconscious
muscle activities. Loss of these neurons results in
Parkinson disease.
 Cranial nerves III (oculomotor) and IV (trochlear)
originate here.
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 Type: sensory.
 Function: smell.
 Anosmia – loss of sense of smell.
 Does not connect with the brainstem.
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 Type: sensory.
 Function: vision.
 Anopia – blindness in one or both eyes.
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 Type: mixed (mainly motor).
 Function: movement of the upper eyelid and
eyeball. Accomodation of the lens for near vision
and constriction of the pupil.
 Strabismus – deviation of the eye in which both
eyes don’t focus on the same object.
 Ptosis – drooping of the upper eyelid.
 Diploia – double vision.
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 Type: mixed (mainly motor).
 Function: movement of the eyeball.
 Diplopia and strabismus occur with trochlear nerve
damage.
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 Type: mixed.
 Function: conveys impulses for touch, pain,
temperature and proprioception. Chewing.
 Trigeminal neuralgia (tic douloureux) – pain to
branches of the trigeminal nerve.
 Dentists apply anesthetic to branches of this nerve.
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 Type: mixed (mainly motor).
 Function: movement of the eyeball.
 With damage to this nerve the eye cannot move
laterally beyond the midpoint and usually points
medially.
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 Type: mixed.
 Function: Propriception and taste. Facial expression.
Secretion of saliva and tears.
 Injury produces bell’s palsy (paralysis of facial
muscles).
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 Type: mixed (mainly sensory).
 Function: conveys impulses for equilibrium and
hearing.
 Injury can cause vertigo, ataxia (muscular
incoordination), nystagmus (rapid movement of the
eyeball), and tinnitus.
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 Type: mixed.
 Function: taste and somatic sensations from the
posterior 1/3 of the tongue. Elevates the pharynx
during swallowing and speech. Stimulates the
secretion of saliva.
 Injury causes decreased salivary secretion, loss of
taste, and difficulty swallowing.
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 Type: mixed.
 Function: taste and somatic sensations. Swallowing,
coughing, and voice production. Regulates GI tract
and heart rate.
 Injury interferes with swallowing, paralyzes vocal
cords, and causes the heart rate to increase.
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 Type: mixed (mainly motor).
 Function: Proprioception. Swallowing, movement of
head and shoulders.
 If the nerves are damaged the SCM and Trapezius
become paralyzed.
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 Type: mixed (mainly motor).
 Function: Proprioception. Movement of the tongue
during speech and swallowing.
 Injury results in difficulty in chewing, speaking, and
swallowing. When protruded, the tongue curls
towards the affected side and atrophies on the affected
side.
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 I – Olfactory
 VII – Facial
 II – Optic
 VIII – Auditory
 III – Oculomotor
 IV – Trochlear

 V – Trigeminal

 VI – Abducens


(Vestibulocochlear)
IX – Glossopharyngeal
X – Vagus
XI – Spinal accessory
XII - Hypoglossal
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 On Old Olympus’ Towering Tops A Fin And German
Viewed Some Hops.
 This mnemonic device helps you memorize the names
of the cranial nerves.
 The first letter from each word corresponds to the first
letter of each cranial nerve.
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 Some Say Marry Money, But My Brother Says Big




Brains Matter Most.
This mnemonic device helps you memorize the
sensory / motor distribution of the cranial nerves.
S = sensory
M = Motor
B = Both
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 Twelve pairs of cranial nerves exit from the brain and
brainstem.
 These nerves innervate the face, head, and neck.
 They control all sensory and motor functions in these
areas including the special senses of vision, hearing,
smell, and taste.
 Cranial trauma, infections, aneurysm, stroke,
degenerative diseases (i.e. multiple sclerosis), upper
motor neuron lesions, lower motor neuron lesions,
increased intracranial pressure, and abnormal masses
or tumors can all affect the cranial nerves.
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 Some facial movements are performed in bilateral
synchrony such as swallowing and moving the
forehead and are thus innervated bilaterally.
 Fine movements of the face are unilateral. The
contralateral hemisphere innervates the affected area.
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