Cranial Nerves Flashcards

1
Q

what is the name of CNI?

A

Olfactory

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2
Q

what is the pathway of the olfactory nerves?

A

receptors in olfactory epithelium of nasal cavity, olfactory nerve fibres pass through foraminifera in cribriform plate of ethmoid bone and enter olfactory bulb in the anterior cranial fossa

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3
Q

what are the components of the olfactory nerves?

A

special sensory - smell

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4
Q

what is the clinical application of the olfactory nerves?

A

fractured cribriform plate may tear olfactory nerve fibres causing anosmia

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5
Q

what is the name of CNII?

A

optic

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6
Q

what is the pathway of the optic nerves?

A

enters via optic canal, nerves join to form optic chiasm, fibres from medial (nasal) half of each retina cross to form optic tract

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7
Q

what are the components of the optic nerves?

A

special sensory - vision

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8
Q

what is the clinical application of the optic nerves?

A
  • increase in CSF pressure can cause papilloedema
  • section of right optic nerve causes blindness through right eye
  • section of optic chiasm causes loss of peripheral vision
  • section of right optic tract causes blindness in left temporal and right nasal fields
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9
Q

what is the name of CNIII?

A

oculomotor

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10
Q

what is the pathway of the oculomotor nerves?

A

emerges from midbrain and exits via superior orbital fissure

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11
Q

what are the components of the oculomotor nerves?

A

somatic motor - extraocular muscles (except SO) and eyelid
visceral motor - parasympathetic to pupil causing constriction and to ciliary muscle causing accommodation of the lens

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12
Q

what is the clinical application of the oculomotor nerves?

A

drooping of upper eyelid (ptosis)
eyeball abducted and pointing down
no pupillary reflex
no accommodation of the lens

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13
Q

what is the name of CNIV?

A

Trochlear

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14
Q

what is the pathway of the trochlear nerves?

A

emerges from dorsal surface of the mid brain and exits via the superior orbital fissure

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15
Q

what are the components of the trochlear nerves?

A

somatic motor - extraocular muscle (superior oblique turns eye downwards)

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16
Q

what is the clinical application of the trochlear nerves?

A

diplopia when looking down

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17
Q

what is the name of CNV1?

A

Trigeminal (ophthalmic)

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18
Q

what is the pathway of the ophthalmic nerves?

A

emerges from the pons, travels through the trigeminal ganglion and exits via the superior orbital fissure

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19
Q

what are the components of the ophthalmic nerves?

A

General sensory - from cornea, forehead, scalp, eyelids, nose and mucosa of nasal cavity and sinuses

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20
Q

what is the name of CNV2?

A

Trigeminal (maxillary)

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21
Q

what is the pathway of the maxillary nerves?

A

emerges from the pons, travels through the trigeminal ganglion and exits via the foramen rotundum

22
Q

what are the components of the maxillary nerves?

A

General sensory - from face over maxilla, maxillary teeth, temperomandibular joint, mucosa of nose, maxillary sinuses and palate

23
Q

what is the name of CNV3?

A

Trigeminal (mandibular)

24
Q

what is the pathway of the mandibular nerves?

A

emerges from the pons, travels through the trigeminal ganglion and exits via the foramen ovale

25
Q

what are the components of the mandibular nerves?

A

General sensory - from face over mandible, mandibular teeth, temperomandibular joint, mucosa of mouth & anterior 2/3rds of tongue
Somatic motor - muscles of mastication, part of digastric, tensor veli palatinin & tensor tympani

26
Q

what is the clinical application of the mandibular nerves?

A

paralysis of muscles of mastication
loss of corneal or sneezing reflex
loss of sensation in the face
trigeminal neuralgia

27
Q

what is the name of CNVII?

A

facial

28
Q

what is the pathway of the facial nerves?

A

emerges between pons and medulla and exits via internal acoustic meatus, facial canal and stylomastoid foramen

29
Q

what are the components of the facial nerves?

A

somatic motor - muscles of facial expression & scalp, stapedius of middle ear, part of digastric muscle
visceral motor - parasympathetic innervation of submandibular & sublingual salivary glands, lacrimal glands, glands of nose & palate
special sensory - taste from anterior 2/3rd of tongue & soft palate
general sensory - from external acoustic meatus

30
Q

what is the clinical application of the facial nerves?

A

most frequently injured - due to long pathway through bone

Bell’s palsy - cannot frown, close eyelid, or bare teeth

31
Q

what is the name of CNVIII?

A

Vestibulocochlear

32
Q

what is the pathway of the vestibulocochlear nerves?

A

emerges from between pons and medulla and exits via internal acoustic meatus, dividing into vestibular & cochlear nerves

33
Q

what are the components of the vestibulocochlear nerves?

A

special sensory - vestibular sensation from semicircular ducts, utricle, saccule gives sense of position & movement
hearing from spiral organ

34
Q

what is the clinical application of the vestibulocochlear nerves?

A

tinnitus (ringing in the ears)
deafness (conductive vs sensorineural)
vertigo (loss of balance)
nystagmus (involuntary rapid eye movements)

35
Q

what is the name of CNIX?

A

glossopharyngeal

36
Q

what is the pathway of the glossopharyngeal nerves?

A

emerges from medulla and exits via jugular foramen

37
Q

what are the components of the glossopharyngeal nerves?

A

special sensory - taste from posterior 3rd of tongue
general sensory - cutaneous sensations from middle ear and posterior oral cavity
visceral sensory - sensation from carotid body & carotid sinus
visceral motor - parasympathetic innervation of parotid gland
somatic motor - to stylopharyngeus, helps with swallowing

38
Q

what is the clinical application of the glossopharyngeal nerves?

A

loss of gag reflex and taste from back of tongue

associated with injuries to CNs X and XI - jugular foramen syndrome

39
Q

what is the name of CNX?

A

vagus

40
Q

what is the pathway of the vagus nerves?

A

emerges from medulla and exits via jugular foramen, then everywhere!

41
Q

what are the components of the vagus nerves?

A

special sensory - taste from epiglottis and palate
general sensory - sensation from auricle, external acoustic meatus
visceral sensory - from pharnyx, larynx, trachea, bronchi, heart, oesophagus, stomach, intestine
visceral motor - parasympathetic innervation muscle in bronchi, gut, heart
somatic motor - to pharynx, larynx, palate & oesophagus

42
Q

what is the clinical application of the vagus nerves?

A

damage to pharyngeal branches cause difficulty in swallowing

damage to laryngeal branches causes difficulty in speaking

43
Q

what is the name of CNXI?

A

accessory

44
Q

what is the pathway of the vagus nerves?

A

small cranial (medulla) and large spinal roots exit via jugular foramen

45
Q

what are the components of the vagus nerves?

A

somatic motor - striated muscle of soft palate, pharynx & larynx, and to sternocleidomastoid & trapezius

46
Q

what is the clinical application of the vagus nerves?

A

weakness in turning head and shrugging shoulder

47
Q

what is the name of CNXII?

A

hypoglossal

48
Q

what is the pathway of the hypoglossal nerves?

A

emerges from medulla and exits through the hypoglossal canal

49
Q

what are the components of the hypoglossal nerves?

A

somatic motor - to muscles of tongue

50
Q

what is the clinical application of the hypoglossal nerves?

A

vulnerable to damage during tonsillectomy

causes paralysis & atrophy of ipsilateral half of tongue. Tip deviates towards affected side