Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Head And Neck > Cranial Nerves VI-XII > Flashcards

Cranial Nerves VI-XII Flashcards

1
Q

Describe the pathways of the 3 branches of the Trigeminal Nerve after branching off the Trigeminal Ganglion

A

Ophthalmic: Through Cavernous sinus then through Superior Orbital Fissure

Maxillary: Through Cavernous Sinus then through Foramen Rotundum

Mandibular: Through Foramen Ovale into Infratemporal Fossa

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

Identify 2 important distal sensory divisions of Va

A
  • Frontal Nerve, which gives rise to Supraorbital and Supratrochlear nerves
  • Nasociliary Nerve (Hutchinson’s Sign)

(Also Lacrimal nerve)

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

Identify 2 important distal sensory divisions of Vb

A
  • Infra-orbital Nerve

- Superior Alveolar Nerves

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

Identify 3 important distal sensory divisions of Vc

A
  • Auriculotemporal nerve
  • Lingual nerve (general sensation from anterior 2/3 of tongue)
  • Inferior Alveolar Nerve and Mental Nerve

(Distal motor divisions go to supply Muscles of Mastication)

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

Not all cases of Opthalmic Shingles (Reactivation of VZ in Va region) extend down into nose.

When does this happen?

A

Only happens when Nasocliary branch of Va is involved

This nerve therefore innervates the tip of nose and also around front of eye

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

What is Hutchingon’s sign?

What is significant about this?

A
  • Presence of crusting and vesicular rash at tip of nose

- Increases risk of Opthalmic Shingles affecting front of eye

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

Describe the inwards to outwards path of Infra-orbital branch of Vb and state why it is vulnerable to injury

(Sensory nerves)

A
  • Passes through floor of orbit, hence at risk of injury in orbital fractures
  • Exits through Infra-orbital Foramen (visible externally)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the outwards to inwards path of the Superior Alveolar branches of Vb

(Sensory nerves)

A
  • Run up Maxilla, carrying sensory information from Teeth and Gums
  • Joins Infraorbital Nerve to connect to CNS

(Therefore damage to Indra-orbital nerve can lead to loss of sensation in Vb and Vc dermatomes)

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

State the region of head innervated by the;

  • Auriculotemporal nerve
  • Lingual nerve
  • Inferior Alveolar and Mental nerves
A
  • Auriculotemporal: Parts of lateral scalp and ear
  • Lingual: Anterior 2/3 of tongue
  • Inferior Alveolar and Mental nerves: Lower teeth, gums, lip, chin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the inward to outward pathway of Inferior Alveolar nerve and its relationship to the Mental nerve

(After Auriculotemporal and Lingual branches have come off)
(Sensor nerve)

A
  • Enters Mandibular Foramen and passes through Mandibular Canal (In Mandibular body)
  • Emerges through Mental Foramen, to become the Mental Nerve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why do dentists insert local anaesthetic into the Inferior Alveolar Nerve near Mandibular Foramen?

Why does your tongue often go numb in this process?

A
  • Prevents sensory information from Mental and IO nerves being carried to CNS, preventing pain
  • Due to proximity of Lingual nerve to IO nerves, Lingual nerve is often also affected by local anaesthetic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The Facial Nerve comes off the Pons. It has motor, sensory and parasympathetic function

What are its target tissues for each function?

A

Motor- Facial expression muscles

Sensory- Taste from anterior 2/3 of tongue

Parasympathetic- Glands (Salivary, Lacrimal)

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

How do patients with a facial nerve lesion present?

A
  • Unilateral facial droop (whole half of affected side)

- May have other symptoms too

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

List 6 causes of Facial Nerve Lesion

A
  • Basal skull fracture (involving petrous bone)
  • Middle Ear Disease
  • Lesions in/ around internal acoustic meatus
  • Posterior cranial fossa tumours
  • Parotid disease
  • Inflammation in facial canal-> Facial nerve palsy (E.g Bell’s Palsy, Ramsay Hunt syndrome)

(All these causes affect the facial nerve along its route after leaving brainstem)

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

How do Ramsay-Hunt Syndrome patients present in 2 ways?

A
  • Presence of vesicles/ rash within external ear (related to Varicella Zoster infection)
  • Ipsilateral face droop
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Outline the path off the Facial Nerve

A
  • Comes off Pons and passes through Internal Acoustic Meatus into Petrous Bone
  • In Petrous Bone, gives off 3 branches, then runs through Facial Canal (closely related to Middle Ear)
  • Emerges through Base of Skull via Stylomastoid Foramen, runs through Parotid Gland, then gives off Extra cranial branches to muscles of facial expression
17
Q

Describe the path of the Facial nerve once it enters the Petrous Bone and how it gives of 3 branches here

A
  1. Runs through Geniculate Ganglion where the parasympathetic Greater Petrosal branch comes off and emerges from Petrous Bone
  2. Runs through Middle Ear Cavity and gives off a motor branch, the Nerve to Stapedius
  3. Runs through Middle Ear cavity and gives of a sensory AND parasympathetic branch, the Chorda Tympani (Parasympathetic fibres need to get to salivary glands)
18
Q

How do we tell the difference between a Stroke and Ipsilateral Facial Droop?

A

Stroke- Only lower half of face affected

Facial Droop- Whole half of face affected

19
Q

Strokes only affect 1 hemisphere at a time and are central in the brain. Facial nerve lesions occur after facial nerve has left the pons.

Use this information to explain why Strokes only affect the Contralateral Lower Half of Face

A
  • Stroke affects motor fibres before they leave the Pons, thus affecting Contralateral Motor Nuclei to Upper and Lower face muscles
  • Ipsilateral ‘back up’ fibres ONLY synapse with Motor Nuclei to Upper face muscles (NOT with Lower face nuclei)
  • Therefore Upper Half of face is only supplied by ‘Ipsilateral back up’
20
Q

Strokes only affect 1 hemisphere at a time and are central in the brain. Facial nerve lesions occur after facial nerve has left the pons.

Use this information to explain why Facial Nerve Lesions affect the Contralateral Whole Face

A

Lesion affects motor fibres AFTER they leave Pons, so absolutely no motor impulses reach Face muscles, regardless of whether they are Upper or Lower face

(Ipsilateral back up fibres affected as well, so upper face muscles affected too)

21
Q

The Vestibulocochlear is a special sensory nerve that arises from the Pons.

Describe its path from the pons

A
  • Comes off pons, travels short distance then through Internal Auditory Meatus into Petrous Bone
  • In PB, branches to Innervate the Vestibular System and Cochlea
22
Q

How do we test the Vestibulocochlear nerve?

A
  • Bedside hearing tests (whisper/ finger rub)

- Tuning fork testing

23
Q

How can patients with a Vestibulocochlear nerve lesion present?

A
  • Hearing loss
  • Possibly Dizziness/ Vertigo
  • Possibly Tinnitus
24
Q

What are 4 possible causes of a Vestibulocochlear nerve lesion?

A
  • Vestibular Schwannoma/ Acoustic Neuroma (and other posterior cranial fossa tumours)
  • Occlusion of labyrinthe artery
  • Basal skull fracture (involving petrous bone)
  • Brainstem lesion (pons)
25
Q

What are 4 symptoms of Vestibular Schwannoma/ Acoustic Neuroma?

A
  • Unilateral hearing loss
  • Tinnitus (hearing noises not caused by an outside source)
  • Vertigo
  • Numbness/ pain/ weakness down one half of face (Due to tumour exerting pressure on Trigeminal/ Facial nerve )
26
Q

Describe the pathway of the Glossopharyngeal and Vagus nerves

(Tend to be examined together as often involved together)

A
  • Arise from Medulla and run through Posterior Cranial Fossa

- Exit through Jugular Foramen and enter Carotid Sheath

27
Q

The Glossopharyngeal nerve is mainly sensory.

List 5 of its target tissues

A
  • Oropharynx/ tonsils (Sensory)
  • Post 1/3 tongue
  • Parasympathetic innervation to parotid gland
  • Carotid Sinus and Body
  • 1 Swallowing muscle (Gives branches that join with vagus to form pharyngeal plexus)
28
Q

The Vagus nerve is Motor and Sensory.

List 3 of its target tissues

A
  • Larynx and Pharynx muscles including soft palate muscles (Motor)
  • Larynx (Sensory)
  • Parasympathetic to many tissues of body
29
Q

How do patients with a Glossopharyngeal/ Vagus nerve lesion present?

A
  • Difficultly with swallowing
  • Weak cough
  • Voice change/ difficulty with speech
30
Q

How do we test Glossopharyngeal/ Vagus nerves?

A
  • Ask patient to speak/ swallow/ cough
  • Asses Soft palate movement (tests vagus nerve)
  • Asses uvula position
  • Can check Gag Reflex (Afferent IX, Efferent X)
31
Q

What is common to the cranial nerves exiting the medulla? (9,10,11,12)

A

Enter carotid sheath (Leave at different points)

32
Q

Outline the path of the Accessory and Hypoglossal nerves

A
  • Arise from medulla (XI also has some contribution from upper cervical spinal nerves)

Run through posterior cranial fossa;

  • Accessory nerve runs through Jugular Foramen
  • Hypoglossal nerve runs though Hypoglossal canal

Enter Carotid Sheath together;

  • Hypoglossal exits and travels towards tongue
  • Accessory nerve exits and travels towards posterior triangle
33
Q

The Hypoglossal nerve is purely motor. What is it responsible for?

What are 3 causes of a Hypoglossal nerve lesion

A

Tongue movements and protrusion

  • Surgery/ pathology near/ involving Upper carotid sheath/ Internal/ External carotid artery
  • Posterior cranial fossa tumours
  • Medullary lesions involving Hypoglossal nucleus
34
Q

Explain how a Hypoglossal nerve lesion can be seen via assessing tongue protrusion

A
  • Hypoglossal nerve innervates ipsilateral Genioglossus muscle which protrudes tongue
  • Lesion of CN XII will cause weakness of Genioglossus muscle
  • Genioglossus on affected side will be over-powered by that of the unaffected side, and tongue will protrude towards affected side
35
Q

The Accessory nerve is purely motor. Name its 2 target tissues

How do we test their actions?

A

SCM;
- Turn head against resistance

Trapezius;
- Shrug shoulders against resistance

36
Q

What are 4 causes of CN XI Lesion?

A
  • Posterior cranial fossa tumours
  • Basilar Skull Fracture
  • Medullary lesions
  • Injury/ surgery/ pathology involving posterior triangle
37
Q

Describe the path of the accessory nerve to trapezius, with reference to SCM

A
  • Emerges deep to posterior border of SCM to enter Posterior Triangle
  • Runs superficially in posterior triangle to reach trapezius

Head And Neck (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions