Cranial Nerves Year 2

Question 1

Cranial nerve and there part of the examination

Answer 1

Olfactory
- have you noticed a change in your sense of smelll

Optic

• get them to read something
• visual fields test - finger should be halfway between you and the patient
• pupillary light reflex, direct reflex, consueal reflex in each eye

Abducens, trochlear and oculomotor nerve
- movement of the eye H sign - ask them if they see double

trigeminal sensory aspect of the nerve
- sensation of the face - ask if they feel your touching it, if it is normal and the same both side

trigeminal nerve
- open your mouth and prevent me from closing it

facial nerve

• muscle of facial expression
• puff out your cheeks
• toothy grin

vestibulocochlear?
- whisper 2 digit number and mask it on the other side

vagus/glossopharyngeal?
- visualise the soft palate and get them to say ahh

Hypoglossal Nerve
- ask them to stick the tongue out

Spinal accessory Nerve
- shurg there shoulders

Question 2

What are you looking for in inspection

Answer 2

• May reveal a facial palsy
  Ptosis
• Ophthalmoplegia (eye patch)
• Craniotomy scars (not usually obvious from an anterior inspection, can look behind the ear)
• PEG/trachy - due to not being able to swallow properly

Question 3

what can an introduction reveal

Answer 3

May reveal a dysphasia or dysphonia

May reveal a decreased conscious level

Question 4

Name the cranial nerves and there number

Answer 4

I = Olfactory
II = Optic
III = Oculomotor
IV = Trochlear
V = Trigeminal
VI = Abducens
VII = Facial
VIII= Auditory (vestibulo cochlear)
IX = Glossopharyngeal
X = Vagus
XI = Accessory
XII= Hypoglossal

Question 5

How do you test for olfactory

Answer 5

Have you noticed any change in your senses of taste or smell?

Question 6

describe an example of acuity

Answer 6

– “6/36” means “I can see at 6m what an average person can see at 36m”

Question 7

How do you test acuity

Answer 7

= ask them to read something
= ask them if they are wearing their glasses
= remember to examine each eye separately - cover one eye get them to read and cover the other eye and get them to read
- use a snellen chart in order to quantify it (won’t use one as you won’t have one and won’t have the distant marked on the floor)

Question 8

How do you examine the visual fields

Answer 8

Fields – tested by confrontation

This allow you to compare the patients visual fields to your own (assumed normal)

In quadrants

One eye at a time

Question 9

name some eye defects that can arise

Answer 9

1 Monocular blindness
2 Bitemporal hemianopia
3 Contralateral homonymous hemianopia
5 C. hom. inferior quadrantanopia
6 C. hom. superior quad

Question 10

how do you examine the pupillary light reflex

Answer 10

using a pen torch

Question 11

what are the 6 reflexes to test

Answer 11

• direct
• consensual
• accommodation - bringing one finger in towards the patients nose and as there eyes converge their pupils constrict
  = these these in each eye

Question 12

name some pupillary abnormalities

Answer 12

Small pupil (miosis) - opiate drugs can cause the pupils to constrict, tend to be smaller in older people as well
can be due to:  
= Drugs eg Opiates
= Pons
= Horner’s syndrome
= Old age

Dilated pupil (mydriasis) = sometimes done on purpose to get a better view 
can be due to:
- Drugs eg Atropine
- Oculomotor palsy
- Ocular trauma (irregular)

Question 13

what does a fundoscopy allow you to do

Answer 13

– you can actually see the end of the second cranial nerve

Question 14

How do you check for colour vision

Answer 14

Colour vision – Ishihara chart

= can check for colour blindness

Question 15

what causes horizontal movements in the eye

Answer 15

medial rectus = moves inwards (adduction)

lateral recuts = moves outwards (abduction)

Question 16

what nerve supplies the lateral rectus

Answer 16

abducens nerve

Question 17

describe what the eye muscles do

• superior oblique
• inferior oblique
• superior rectus
• inferior rectus

Answer 17

• Superior oblique = inycloduction
• inferior oblique = excyloduction

superior rectus

• elevation
• adduction

inferior rectus
- depression
adduction

Question 18

How do you test superior and inferior rectus

Answer 18

but with the eye abducted, the superior and inferior recti move the eye up and down

Question 19

How do you test superior and inferior oblique

Answer 19

with the eye adducted, the inferior and superior obliques move the eye up and down

Question 20

what does oculomotor palsy result in

Answer 20

An oculomotor palsy results in a dilated pupil and a depressed, abducted eye (down and out)

Question 21

How do you examine the trigeminal nerve

Answer 21

Examine facial sensation to fine touch in all 6 areas

Muscles of mastication “clench your teeth” “open your mouth”

Jaw jerk

Question 22

How do you examine the facial nerve

Answer 22

“Raise your eyebrows”
“Screw your eyes tight shut”
“Puff out your cheeks”
“Big smile”

Question 23

why does an UMN spares the forehead in the face

Answer 23

An UMN weakness 
of the face, spares 
the forehead.
Because the forehead
area of the facial
nucleus is innervated by
both motor cortices.

Question 24

Why might facial weakness develop

Answer 24

bells palsy - knocks out the whole side the face

stroke - only bottom half of the face as UMN

Question 25

describe how the corneal reflex works

Answer 25

Stroking the cornea with a wisp of cotton wool, causes the eye to blink

Vophth & VII

Part of brain stem tests= maybe if they are brain dead

Can cause corneal abrasion thus not routinely performed

Question 26

How do you test the vestibule-cochlear nerve

Answer 26

A crude bedside test
Mask one ear with tragal massage
Whisper a number into the tested ear
Ask the patient to repeat the number

Question 27

what tuning fork do you use for weber and rhinne

Answer 27

512Hz tuning fork

Question 28

describe how weber and rhinne test works

Answer 28

The basis for the tests is sensory adaptation – when there is a conduction defect in an ear, the hair cells receive less stimulation and so become hypersensitive.

Acoustic conduction can be bypassed by placing a tuning fork on the skull – in which the cochlear is embedded

(don’t do in the exam)

Question 29

describe how you form the weber and rhinne test

Answer 29

Weber - in which ear is the sound louder?
Rinne – which is louder? Air or bone?

In a R conductive deafness, Weber localises to R and bone stimulus is louder on Rinne
In a R sensorineural deafness, Weber localises to L and air stimulus is louder on Rinne

Question 30

How do you test for cranial nerves IX, X and XI

Answer 30

Open mouth, say “ah”

The uvula will be seen to elevate. It will deviate away from the side of a bulbar palsy

Gag reflex – when the posterior pharyngeal wall is stimulated with a cotton bud, the patient gags. This is an unpleasant thing to do to someone.

Question 31

how do you examine spinal accessory nerve

Answer 31

Shrug you shoulders”

Tests trapezius

Question 32

How do you examine XII

Answer 32

Stick out your tongue”
Look for fasciculation and wasting
Deviates towards side of palsy (the muscles of the tongue are pushing it out