Cranial nerves Flashcards

1
Q

What are the 4 fibre types that make up the cranial nerves?

A
  1. General sensory (sense of touch)
  2. Special sensory (smell, sight, taste, hearing and balance)
  3. Somatic motor (under conscious control)
  4. Parasympathetic (both afferent and efferent)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

CN I

Fibre type:
Summary of action:
Originates..:
Exits cranial cavity via…:
Sensors in..:

A

> Olfactory nerve
* 1 fibre type – special sense
* Summary of action: sense of smell
* Originates as an extension of the telencephalon (part of forebrain)
* Exits cranial cavity via cribriform plate
* Sensors in superior part of nasal cavity

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

CN II

Fibre type:
Summary of action:
Originates..:
Exits cranial cavity via…:
Sensors in..:

A

> Optic nerve
* 1 fibre type – special sense
* Summary of action: sense of sight
* Originates from diencephalon as a tract or extension
* Exits cranial cavity via optic canal
* Sensors in retina

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

CN III

Fibre type:
Summary of action:
Originates..:
Exits cranial cavity via…:
Sensors in..:

A

> Oculomotor nerve
* 2 fibre types – somatic motor and parasympathetic
* Summary of action: motor innervation to majority of extrinsic eye muscles, parasympathetic motor innervation to intrinsic eye muscles
* Originates from anterior surface of midbrain
* Exits cranial cavity through superior orbital fissure
* Targets in and around eye and orbit

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

CN IV
Fibre type:
Summary of action:
Originates..:
Exits cranial cavity via…:
Sensors in..:

A

> Trochlear nerve
* 1 fibre type: somatic motor
* Summary of action: motor to superior oblique extrinsic muscle of the eye
* Originates from posterior surface of midbrain
* Exits cranial cavity via superior orbital fissure
* Target in orbit

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

CN VI
Fibre type:
Summary of action:
Originates..:
Exits cranial cavity via…:
Sensors in..:

A

> Abducens nerve
* 1 fibre type: somatic motor
* Summary of action: motor innervation to the lateral rectus extrinsic muscle of the orbit
* Originates between pons and medulla
* Exits cranial cavity via superior orbital fissure
* Target in orbit

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

CN V
Fibre type:
Summary of action:
Originates..:
Exits cranial cavity via…:
Sensors in..:

A

> Trigeminal nerve
* 2 fibre types: general sensory and somatic motor
* Summary of action: sensation across face and anterior scalp, motor to muscles of mastication 1- temporalis 2- masater
* Originates from pons, with a large sensory ganglion & a number of nuclei
* Exits cranial cavity via superior orbital fissure, foramen ovale and foramen rotundum

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

> Trigeminal nerve:

1- Name the 3 devisions.

2- What is the specific function of CNV1/2 compared to CNV3?

A

1.
- CNV1= Ophthalmic branch
- CNV2= Maxillary branch
- CNV3= Mandibular branch

> They all provide general somato-sensation across face and anterior scalp BUT CNV3 the mandibular nerve also has a somatic motor function.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

> Trigeminal nerve:

1- What do the 3 devisions innervate?

A
  • CNV1 - tip of nose, above the corner of eye
  • CNV2 - from corner of eye to the corner of the mouth (maxilla region)
  • CNV3 - from corner of mouth to edge of chin (mandible region)e.g. innervates anterior 2/3 of tongue
  • The motor function of mandibular nerve innervates Mastication muscles (muscles which enable chewing)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where do the CNV exit from out of cranial cavity?

A

3 regions-

  • CNV1= Ophthalmic nerve exit via the superior orbital fissure
  • CNV2= Maxillary nerve exit via the foramen rotundum
  • CNV3= Mandibular nerve exit via the foramen ovale
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How are parasympathetic fibres associated with trigeminal nerves?

A

> Parasympathetic fibres from other cranial nerves synapse in ganglion and some fibres proceed to join onto a trigeminal branch to reach their destination

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

CN VII
Fibre type:
Summary of action:
Originates..:
Exits cranial cavity via…:
Sensors in..:

A

> Facial nerve
* 4 fibre types: special sense, general sense, somatic motor, parasympathetic motor

  • Summary of action:
  • Somatic motor innervation to the facial expression muscles
  • General sensory innervation to part of pinna
  • Special sensory and parasympathetic innervation which both run together:
    > special sensory innervate
    anterior 2/3 of tongue = allows for taste
    > parasympathetic counterparts innervate Sub-mandibular and sublingual salivary glands = allows salivation
  • Parasympathetic innervation = Lacrimal gland and mucosa of nasal cavity and sinus
  • Originates from pons-medullary junction
  • Exits cranial cavity via internal acoustic meatus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q
  1. Where do the CNVII exit from out of cranial cavity?
  2. After leaving the …. the stylomastoid foramen is the final exit for some branches. What branches emerge from this 2nd exit?
A
  1. Internal acoustic meatus
    • Parotid plexus
    • Posterior auricular nerve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

CN VIII
Fibre type:
Summary of action:
Originates..:
Exits cranial cavity via…:
Sensors in..:

A

> Vestibulocochlear nerve
* 1 fibre type: special sensory
* Summary of action: detection of sense of balance and sense of hearing
* Originates from pons-medullary junction
* Sensors in inner ear in temporal bone
* Exits cranial cavity via internal acoustic meatus

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

CN IX
Fibre type:
Summary of action:
Originates..:
Exits cranial cavity via…:
Sensors in..:

A

> Glossopharyngeal nerve
* 4 fibre types: special sensory, general sensory, somatic motor and parasympathetic
* Summary of action:
- special sensory to taste to posterior 1/3 of tongue,
- general sensory to posterior 1/3 of tongue and all pharynx,
- somatic motor innervation to stylopharyngeus,
- parasympathetic to parotid salivary glands
* Originates from upper medulla oblongata
* Sensors and targets around throat
* Exits cranial cavity via jugular foramen

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

CN X
Fibre type:
Summary of action:
Originates..:
Exits cranial cavity via…:
Sensors in..:

A

> Vagus
* 4 fibre types: special sensory, general sensory, somatic motor and parasympathetic
* Summary of action:
- Special sensory for taste to epiglottis,
- General sensory for sensation to part of pinna,
- Somatic motor innervates pharynx and larynx,
- parasympathetic innervation to thoracic and abdominal viscera
* Originates from medulla
* Sensors and targets in posterior half of head, pharynx and torso
* Exits cranial cavity via jugular foramen

17
Q

CN XI
Fibre type:
Summary of action:
Originates..:
Exits cranial cavity via…:
Sensors in..:

A

> Spinal accessory nerve
* 1 fibre type: somatic motor
* Summary of action: Innervation to trapezius and sternocleidomastoid muscles
* Originates from lateral aspect of spinal cord and brainstem
* Targets in neck and back
* Exits cranial cavity via jugular foramen

18
Q

CN XII
Fibre type:
Summary of action:
Originates..:
Exits cranial cavity via…:
Sensors in..:

A

> Hypoglossal nerve
* 1 fibre type: somatic motor
* Summary of action: Innervate intrinsic and extrinsic muscles of tongue
* Originates from medulla
* Targets in tongue and neck
* Exits cranial cavity via hypoglossal canal

19
Q

What makes up the sympathetic chain?
.. How do these fibre reach their targets in the head?

A
  • Thoracolumbar spinal nerves
    T1- L2
  1. They travel up and synapse in the sympathetic chain, which sits at either side of the vertebral column
  2. Vertebral column continues up to the base of the skull, where the sympathetic trunk then crosses onto the internal carotid artery and becomes plexiform
  3. They then distribute with the arteries to the targets in the head
20
Q

What are the organising principles of the cranial nerves?

> smell and sight
moving eyeballs
touch and movement in anterior half of head
hearing and balance
touch and movement in
posterior half of head
shrugging muscles
tongue

A
  • I & II – smell and sight
  • III, IV & VI – moving eyeballs
  • V & VII – touch and movement in anterior half of head
  • VIII – hearing and balance
  • IX & X – touch and movement in
    posterior half of head
  • XI – shrugging muscles
  • XII – tongue
21
Q

Label the exists of cranial nerves from cranium.

A
22
Q

Label cranial nerves + cranial foramina.

A