Cranial Nerves Flashcards

1
Q

What are the twelve cranial nerves?

A
One-Olfactory
Two-Optic
Three-Oculomotor
Four-Trochlear
Five-Trigeminal (ophthalmic, maxillary and mandibular branches)
Six-Abducens
Seven-Facial
Eight-Vestibulocohlear
Nine-Glossopharyngeal
Ten-Vagus
Eleven-Accessory
Twelve-Hypoglossal
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2
Q

What is the pathway of the olfactory nerve?

A

Starts at olfactory bulb in anterior cranial fossa then goes through foramina in cribriform plate to reach the olfactory epithelium where it expresses as receptors.

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3
Q

What clinical pathology can affect the olfactory nerve?

A

A fractured cribriform plate from trauma could tear olfactory nerve fibres and cause anosmia.

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4
Q

What is the pathway of the optic nerve?

A

Starts at posterior eyeball and travels through optic canal to the optic chiasm then the optic tract to the posterior part of the brain.

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5
Q

What are some clinical pathologies that affect the optic nerve?

A

Increase in CSF pressure can cause papilledema.

Section of optic nerve, optic chiasm or optic tract can cause different kinds of blindness.

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6
Q

What is the pathway for the oculomotor nerve?

A

Emerges from the midbrain to emerge from the superior orbital fissure.

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7
Q

What are the two components of the oculomotor nerve?

A

Somatic Motor to control the muscles of the eye

Visceral Motor-Parasympathetic to constrict the pupil and control the ciliaris muscle.

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8
Q

What are some clinical presentations of the oculomotor pathology?

A

Ptosis
Eyeball abducted and pointing down
No pupillary reflex
No accommodation of the lens

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9
Q

What is the pathway of the trochlear nerve?

A

From the dorsal surface of the midbrain then goes through the superior orbital fissure.

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10
Q

What is the component of the trochlear nerve?

A

Somatic motor for controlling the superior oblique

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11
Q

What is a clinical presentation of trochlear nerve pathology?

A

Diplopia when looking down (especially noticed going down stairs)

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12
Q

What is the pathway of the abducent nerve?

What is its component?

A

Emerges from between the medulla and pons to exit from the superior orbital fissure
Somatic Motor

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13
Q

What is a clinical presentation of abducent nerve pathology?

A

Diplopia from medial deviation of affected eye.

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14
Q

Where does the trigeminal nerve emerge from and which branch of it has more than one component?

A

Emerges from the pons
All branches have general sensory function but only the mandibular branch has somatic motor for innervation of muscles of mastication, digastric muscle and tensor tympani.

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15
Q

What are some clinical presentations of trigeminal nerve pathology?

A

Trigeminal nerve neuralgia
Muscles of mastication paralysis
Loss of face sensation
Loss of sneezing and corneal reflex

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16
Q

What is the pathway of the facial nerve?

A

Emerges from between the pons and medulla to exit from the internal acoustic meatus.

17
Q

What are the components of the facial nerve?

A

Somatic motor for facial muscle innervation
Special sensory for the anterior two thirds of the tongue
General sensory for internal acoustic meatus
Visceral motor for parasympathetic innervation of some facial glands

18
Q

What is a clinical pathology of the facial nerve?

A

Bells Palsy

19
Q

What is the pathway of the vestibulocochlear nerve?

A

It emerges from between the pons and medulla and comes out of the internal acoustic meatus to divide into the vestibular and cochlear nerves.

20
Q

What are some clinical presentations of vestibulocochlear nerve pathology?

A

Sensorineural hearing loss
Tinnitus
Vertigo
Nystagmus

21
Q

What is the pathway of the glossopharyngeal nerve?

A

It emerges from the medulla and exits via the jugular foramen.

22
Q

What are the components of the glossopharyngeal nerve?

A

Somatic motor for the stylopharyngeus for swallowing
General sensory for the middle ear and posterior oral cavity
Special sensory for the posterior third of the tongue
Visceral motor for the parasympathetic supply of the parotid gland
Visceral sensory from the carotid bodies and sinuses

23
Q

What is the clinical manifestation of a glossopharyngeal nerve pathology?

A

Loss of gag reflex and taste sensation from back of tongue.

24
Q

What is the pathway of the vagus nerve?

A

Emerges from the medulla and traverses the jugular foramen.

25
Q

What are the components of the vagus nerve?

A

Somatic motor for the pharynx, larynx, palate and the oesophagus
Visceral motor for parasympathetic supply in bronchi, gut and heart
Special sensory for taste from epiglottis and palate
General sensory for sensation from auricle, external acoustic meatus
Visceral sensory from pharnyx, larynx, trachea, bronchi, heart, oesophagus, stomach and intestine

26
Q

What are some clinical presentations of vagus nerve pathology?

A

If the laryngeal branch is affected it will cause difficulty in speaking and if the pharyngeal branch is affected then will get difficulty in swallowing.

27
Q

What is the pathway of the accessory nerve?

A

Emerges from the medulla then exits via the jugular foramen.

28
Q

What is the component of the accessory nerve?

A

Somatic motor for striated muscle of soft palate, pharynx & larynx, and to sternocleidomastoid & trapezius

29
Q

What is the clinical presentation of an accessory nerve pathology?

A

Weakness in turning head and shrugging shoulder

30
Q

What is the pathway of the hypoglossal nerve?

A

Emerges from the medulla and exits via the hypoglossal foramen.

31
Q

What is the component of the hypoglossal nerve?

A

Somatic motor to muscles of the tongue

32
Q

What are the clinical presentations of the hypoglossal nerve?

A

Paralysis and atrophy of ipsilateral half of tongue. Tip deviates towards affected side