Cranial Nerves Flashcards

1
Q

What are the cranial nerves?

A

12 pairs of nerves that emerge from the cranium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why are the cranial nerves prone to compression?

A
  • They are soft and squashy
  • They have to pass through holes in hard bone
  • They are prone to compression due to inflammation, tumours and fractures
  • Symptoms relate to the function of the nerves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What may cranial nerves contain?

A
  • Somatic motor fibres
  • Visceral motor fibres
  • Visceral sensory
  • General sensory
  • Special sensory
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What do somatic motor fibre supply?

A

Striated muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What do visceral motor fibres supply?

A

Cranial division of the parasympathetic supply innervates smooth muscle and glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What do visceral sensory fibres supply?

A

Afferent inputs from pharynx, larynx, heart, lung, gut (not normally concious)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What do general sensory fibres supply?

A

Afferent inputs (touch, temperature, pain) from skin and mucous membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What do special sensory fibres supply?

A
  • Taste
  • Smell
  • Vision
  • Hearing
  • Balance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What do all nerve fibres need?

A

Cell bodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What fibres have the cell bodies in the CNS?

A
  • Somatic motor fibres

- Autonomic motor fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What fibres have cell bodies outwith the CNS?

A
  • Sensory fibres

- Autonomic motor fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

CNVI

A

Abducent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

CNIV

A

Trochlear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

CNX

A

Vagus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

CNXII

A

Hypoglossal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

CNII

A

Optic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

CNV

A

Trigeminal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

CNVIII

A

Vestibulocochlear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

CNI

A

Olfactory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

CNXI

A

Accessory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

CNVII

A

Facial

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

CNIII

A

Oculomotor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

CNIX

A

Glossopharyngeal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Olfactory pathway

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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Olfactory components

A

Special sensory smell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Olfactory clinical application

A

Fractured cribriform plate may tear olfactory nerve fibres causing anosmia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Optic pathway

A
  • Enters via optic canal
  • Nerves join to form optic chiasm
  • Fibres from medial half of each retina cross to form optic tract
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Optic components

A

Special sensory vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Optic clinical applications

A
  • Increase in CSF pressure can cause papilledema
  • Section of right optic nerve causes blindness through right eye
  • Section of optic chiasm causes loss of peripheral vision (bitemporal hemianopsia)
  • Section of right optic tract causes blindness in left temporal and right nasal fields (left homonymous hemianopsia)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Oculomotor pathway

A

Emerges from midbrain and exits via superior orbital fissure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Oculomotor components

A
  • Somatic motor: extraocular muscles (superior,medial,inferior rectus and inferior oblique) and eyelid
  • Visceral motor: parasympathetic to pupil causing constriction and to ciliary muscle causing accommodation of the lens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Oculomotor clinical application

A
  • Drooping of upper eyelid (ptosis)
  • Eyeball abducted and pointing down
  • No pupillary reflex
  • No accommodation of the lens
33
Q

Trochlear pathway

A

Emerges from dorsal surface of the midbrain and exits via the superior orbital fissure

34
Q

Trochlear components

A

Somatic motor: extraocular muscle (superior oblique turns eye downwards)

35
Q

Trochlear clinical application

A

Diplopia when looking down

36
Q

Abducent pathway

A

Emerges between pons and medulla and exits via the superior orbital fissure

37
Q

Abducent components

A

Somatic motor: extraocular muscle (lateral rectus abducts the eye)

38
Q

Abducent clinical application

A

Medial deviation of the affected eye causing diplopia

39
Q

Trigeminal V1

A

Ophthalmic

40
Q

Trigeminal V3

A

Mandibular

41
Q

Trigeminal V2

A

Maxillary

42
Q

Trigeminal V1 pathway

A

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

43
Q

Trigeminal V1 components

A

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

44
Q

Trigeminal V2 pathway

A

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

45
Q

Trigeminal V2 components

A

General sensory: from face over maxilla, maxillary teeth, TMJ, mucosa of nose, maxillary sinuses and palate

46
Q

Trigeminal V3 pathway

A

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

47
Q

Trigeminal V3 components

A
  • General sensory: from face over mandible, mandibular teeth, TMJ, mucosa of mouth and anterior 2/3 of tongue
  • Somatic motor: muscles of mastication, part of digastric, tensor veli palatinin and tenor tympani
48
Q

Trigeminal V3 clinical application

A
  • Paralysis of muscles of mastication
  • Loss of corneal or sneezing reflex
  • Loss of sensation in the face
  • Trigeminal neuralgia
49
Q

Facial pathway

A

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

50
Q

Facial components

A
  • Somatic motor: muscles of facial expression and scalp, stapedius of middle ear, part of digastric muscle
  • Visceral motor: parasympathetic of submandibular and sublingual salivary glands, lacrimal glands, glands of nose and palate
  • Special sensory: taste from anterior 2/3 of tongue and soft palate
  • General sensory: from external acoustic meatus
51
Q

Vestibulocochlear pathway

A

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

52
Q

Vestibulocochlear components

A

Special sensory: vestibular sensation from semi-circular ducts, utricle saccule gives sense of position and movement, hearing from spiral organ

53
Q

Vestibulocochlear clinical application

A
  • Tinnitus (ringing in the ears)
  • Deafness (conductive vs sensorineural)
  • Vertigo (loss of balance)
  • Nystagmus (involuntary rapid eye movements)
54
Q

Glossopharyngeal pathway

A

Emerges from medulla and exits via jugular foramen

55
Q

Glossopharyngeal components

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 and carotid sinus
  • Visceral motor: parasympathetic innervation of parotid gland
  • Somatic motor: to stylopharyngeus, helps with swallowing
56
Q

Glossopharyngeal clinical application

A
  • Loss of gag reflex and taste from back of the tongue

- Associated with injuries to accessory and vagus nerves: jugular foramen syndrrome

57
Q

Vagus pathway

A

Emerges from medulla and exits via jugular formane then goes everywhere

58
Q

Vagus components

A
  • Special sensory: taste from epiglottis and palate
  • General sensory: sensation from auricle, external acoustic meatus
  • Visceral sensory: from pharynx, larynx, trachea, bronchi, heart, oesophagus, stomach , intestine
  • Visceral motor: parasympathetic innervation muscle in bronchi, gut, heart
  • Somatic motor: to pharynx, larynx, palate and oesophagus
59
Q

Vagus clinical application

A
  • Damage to pharyngeal branches cause difficulty swallowing

- Damage to laryngeal branches cause difficulty in speaking

60
Q

Accessory pathway

A

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

61
Q

Accessory components

A

Somatic motor: striated muscle of soft palate, pharynx and larynx, sternocleidomastoid and trapezius

62
Q

Accessory clinical application

A

Weakness in turning head and shrugging shoulders

63
Q

Hypoglossal pathway

A

Emerges from medulla and exits through the hypoglossal canal

64
Q

Hypoglossal components

A

Somatic motor: to muscles of tongue

65
Q

Hypoglossal clinical application

A
  • Vulnerable to damage during tonsillectomy

- Causes paralysis and atrophy of ipsilateral half of tongue. Deviates towards affected side

66
Q

Smell

A

Olfactory

67
Q

Sight

A

Optic

68
Q

Taste

A
  • Facial
  • Glossopharyngeal
  • Vagus
69
Q

Hearing and balance

A

Vestibulocochlear

70
Q

Movement of eyes

A
  • Oculomotor
  • Trochlear
  • Abducent
71
Q

Movement of face

A

Facial

72
Q

Sensation from the face

A

Trigeminal

73
Q

Chewing

A

Trigeminal V3

74
Q

Swallowing

A
  • Glossopharyngeal

- Accessory

75
Q

Movement of the tongue

A

Hypoglossal

76
Q

Movement of the vocal cords

A

Vagus

77
Q

Visceral sensory input

A
  • Vagus

- Glossopharnygeal

78
Q

Movement of the neck

A

Accessory

79
Q

Facial Clinical Application

A
  • Most frequently injured due to long pathway though bone

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