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What are the cranial nerves?
- I - Olfactory nerve
- II - Optic nerve
- III - Oculomotor nerve
- IV - Trochlear nerve
- V - Trigeminal nerve
- VI - Abducens nerve
- VII - Facial nerve
- VIII - Vestibulocochlear nerve/Auditory nerve
- IX - Glossopharyngeal nerve
- X - Vagus nerve
- XI - Accessory nerve/Spinal accessory nerve
- XII - Hypoglossal nerve
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Dirty mnemonic for nerves
Oh, Oh, Oh, Tiny Tits And Furry Vaginas Give Victor A Hardon
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mnemonic for function motor/sensory/both
Some Say Marry Money, But My Brother Says Big Boobs Matter Most
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Most cranial nerves arise from the ________, with I and II arising from the __________.
III and IV arise from the _________, V and XII arise from the ____/______.
- brainstem
- diencephalon
- midbrain
- pons medulla
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Motor fiber cells reside ______
Sensory fiber cells reside _______
- in the motor cortex and transmit impulses from brain to tissue outside brain (corticobulbar tract is a collection of UMN axons and controls head/neck)
- in ganglia outside brain and transmit impulses from sensory organs to brain
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Olfactory Nerve (I):
- smell receptors stimulated
- action potential initiated in nasal mucosa
- olfactory bulb gathers info
- sends to other structures of CNS via olfactory tract
(Anosmia)
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Optic Nerve (II):
- carries info from retina past optic chiasm
- to the optic tract, which reaches the occipital lobe via the
- thalamus
damage is predictable given location of damage
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Oculomotor Nerve (III):
- Motor to eyelid and extrinsic eye muscles
- sensory from these muscles to brain
- facilitates pupil dilation and movement of some eye muscles
Damage can result in ptosis
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Trochlear Nerve (IV):
- Motor to eye muscles (allows up and out movement of the eye)
- Sensory from these muscles
Damage can result in diplopia
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Trigeminal Nerve (V):
Largest of the CNs
- motor innervates muscles of mastication (Masseter, Digastric)
- sensory from face, scalp, nose, and mouth (3 divisions)
- Unilateral damage to LMN: ipsilateral jaw deviation
- Unilateral UMN lesion: no significant effect
- Bilateral UMN lesion: significant limitations in jaw movement
- Doctor can test for positive jaw jerk
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Abducens Nerve (VI):
- motor to lateral rectus
- sensory from this muscle to brain
Damage: failure of lateral rectus to abduct (can't look to the side)
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Facial Nerve (VII):
To Zanzibar By Motor Car
(temporal, zygomatic, buccal, mandibular, cervical)
Motor to all muscles of facial expression, lower face has unilateral innervation, upper face has bilateral innervation
Sensory from anterior 2/3rds of tongue and proprioceptive fibers from facial muscles
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Vestibularcochlear Nerve (VIII)
- sensory from vestibular apparatus and semicircular canals about equilibrium
- sensory from organ of corti/cochlea about hearing
Damage results in hearing impairment or vertigo
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Glossopharyngeal Nerve (IX):
- motor to pharyngeal muscle for swallowing and parasympathetic fibers to salivary glands
- Sensory from pharynx, tonsils, posterior 1/3rd of tongue
Damage: swallowing/numbness of ipsilateral pharynx
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Vagus Nerve (X):
- Motor to pharynx, larynx, heart, and other organs
- sensory from neck, chest, and abdomen
Unilateral damage to lower motor lesion: affects larynx, hoarseness, difficulty swallowing
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Accessory Nerve (XI):
- Motor stimulation to sternocleidomastoid and trapezius muscles via spinal fibers
- Motor from medulla innervate soft palate, pharynx, and larynx (cranial root)
- Sensory from the above mentioned
Damage: drooping shoulder, trouble turning head towards lesion
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