Brainscape's Knowledge GenomeTM

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


See full index

MRCS B Examinations and practical skills > cranial nerve examination > Flashcards

cranial nerve examination Flashcards

1
Q

Optic tract lesions

A

-Bitemporal inferior quadrantinopia: Lesion from above (craniopharyngioma)
-Bitemporal superior quadrantinopia: lesion from below (pituitary tumour)
-Lesion between chiasm and eye: unilateral blindness
-Lesion between visual cortex and chiasm: homonymous hemianopia

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

other than bitemporal hemianopia, what are other signs of pituitary tumour

A

-Raised ICP, papilloedema on fundoscopy
-Hyperpituitarism
–> If growth hormone: acromegaly-prognathism, enlarged hands and feet, prominent brow
–> if prolactin: increased lactation, loss of libido in men, erectile dysfunction

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

CN 1: Anatomy and test

A

Bulbs lie inferior to frontal lobe
Then pass inferiorly to reach nasal mucosa
Test: smelling salts

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

Causes of loss of smell

A

Viral infection
Nasal tumour
Frontal cerebral lesions e.g. meningioma

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

Optic nerve: anatomy

A

Optic nerve–> optic canal–> optic chiasm–> nasal fibres cross over–> LGN–> visual cortex

  1. Optic nerve begins at retina
  2. Exits orbit via optic canal
  3. Right and left optic nerves come together anterior to pituitary to form optic chiasm
  4. Nasal fibres from each retina cross over to join temporal fibres that remain uncrossed
  5. Fibres of optic tract travel to lateral geniculate nucleus in the thalamus
  6. Optic radiations travel from LGN to visual cortex
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Causes of loss of visual acuity

A

-Cataract
-Refractive errors

Retinal diseases: macular degeneration

Optic nerve pathology eg optic neuritis

Higher lesions

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

Optic nerve test:

A
  1. Acuity (snellen chart)- 6/6 second number is variable
  2. Fundoscopy
  3. Fields
  4. Colour vision
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

3,4, 6

A

-3 + 4 originate in midbrain, 6 in pons
-Travel in cavernous sinus before exiting skull via superior orbital fissure

Test:
-Eye movements (H shape)
-Direct and consensual pupillary response

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

Anatomy of light reflex

A

Optic nerve –> pretectal nucelus –> efferent fibres to EW nucleus (on both ipsilateral and contralateral)

  1. Afferent limb: optic nerve
  2. Synapses in pretectal nucleus: efferent limbs carried to edinger westfall nucleus on both sides brain (ipsilateral and contralateral)
  3. Efferent fibres of 3 carry light reflex to eye
  4. Synapses in ciliary ganglion along its course
  5. Innervates ciliary sphincter
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does direct and consensual pupillary reflex test?

A

Direct: ipsilateral efferent limb
Consensual: contralateral efferent limb

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

How would palsy of 3 present?

A
  1. Loss of accommodation reflex
  2. Ptosis
  3. Pupillary dilatation
  4. Down and out palsy (unopposed lateral rectus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How would 4 palsy present clinically?

A

Eye deviated upwards: weakening of superior oblique, impairing ability to look downwards
Unable to walk down stairs, read a book

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

How would 6 palsy present clinically?

A

Eye deviated medially (unopposed medial rectus)
Unable to abduct eye

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

How would you test trigeminal nerve?

A
  1. Test all sensory regions with cotton wool
  2. Test corneal reflex
  3. Test muscles of mastication: get pt to clench jaw, then feel temple/side of jaw
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Facial nerve test:

A

Muscles of facial expression

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

What is the difference between UMN and LMN injury to facial nerve?

A

UMN lesion: preservation of frontalis due to dual innervation from both hemispheres.

LMN: frontalis lost, no raising of eyebrows

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

Rinne’s

A

Normal: air conduction better than bone conduction
Sensorineural deafness: air conduction better than bone conduction
Conductive: bone conduction better than air conduction

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

Weber’s test

A

Normal: sound head equally both sides
Sensorineural deafness: sound heard better on unaffected side
Conductive: sound heard better on affected side

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

Vestibulocochlear nerve testing

A

Supplies: hearing and balance

Test:
-Weber’s
-Rinne’s

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

Glossopharyngeal nerve supply and testing:

A

Cranial nerve foramen:
-Jugular foramen

Supply
-Taste posterior 1/3rd tongue
-parasympathetic to parotid gland
-Sensation to palate

To test: touch to each side of uvula and look for gag reflex (i.e. normal sensation): lost on affected side

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

Vagus nerve: path, supply and how to test

A

-Exits via jugular foramen
-Travels in carotid sheath
-Travels inferiorly to supply innervation to pharynx, larynx, palate
-Continues, to supply branches to heart, lungs and gut

Supplies: muscles of larynx and pharynx
Parasympathetic supply to gut

To test: ask pt to open mouth and say ‘ah’: uvula deviates to unaffected side

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

Accessory nerve

A

Originates from nerves in upper spinal cord. Enters skull via foramen magnum, exits again via jugular foramen

Supplies: trapezius and sternocleidomastoid

Test:
-When testing sternocleidomastoid: ask pt to turn to right, palpate left sternocleidomastoid

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

Hypoglossal nerve

A

Supply: all muscles in tongue except palatoglossus (vagus nerve)

Test: stick out tongue: will deviate to affected side (overaction of genioglossus on contralateral side)

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

AMTS score

A

Ask pt to remember address, ask them to repeat at the end (42 west street)

Time
-What time is it to nearest hour/what time of day is it?
-What year is it?

Place
-Where are we?

Person
-What is your age?
-What is your date of birth?

General knowledge
-Who is the prime minister/monarch
-In what year did world war 1 begin?

Other
-Can the pt recognise job roles of two members of staff
-Count backwards from 20-1

25
Q

To complete examination (cranial nerves)

A

-Full neurological examination including the upper and lower limbs.
-Neuroimaging (e.g. MRI head): if there are concerns about space-occupying lesions or demyelination.
-Formal hearing assessment (including pure tone audiometry): if there are concerns about vestibulocochlear nerve function
-Bitemporal hemianompia: endocrine exam, pituitary profile, referral to endocrine and MDT

26
Q

cerebello-pontine angle tumour

A

-Mostly acoustic neuromas
-Most common posterior fossa tumour
-Cranial nerves involved: 5, 7, 8

27
Q

Describe cause of macular sparing

A

Lesions affecting the calcarine sulcus of the occipital lobe tend to cause homonymous hemianopia with sparing of the macula.

Macular vision is spared given the dual blood supply to the anterior portion of the visual centre (PCA and MCA).

28
Q

Name cranial nerve palsy associated with oblique diplopia

A

Oblique diplopia (images appear at an angle to each other) occurs due to dysfunction of both vertical and horizontal muscles.

This type of diplopia is associated with cranial nerve III palsy.

29
Q

Name cranial nerve palsy associated with horizontal diplopia

A

Horizontal diplopia (images appear side-by-side) occurs due to dysfunction of the medial and/or lateral rectus muscles.

This type of diplopia is associated with cranial nerve VI palsy.

30
Q

Name cranial nerve palsy associated with vertical diplopia

A

Vertical diplopia (images appear on top of each other) occurs due to dysfunction of the superior and/or inferior oblique muscles.

This type of diplopia is associated with cranial nerve IV palsy.

31
Q

Describe anatomy of corneal reflex

A

Afferent: ophthalmic division trigeminal nerve
Efferent: facial nerve to orbicularis oculi

32
Q

Describe hypoglossal nerve palsy

A

A hypoglossal nerve (CN XII) palsy causes atrophy of the ipsilateral tongue muscles resulting in tongue deviation towards the side of the lesion

33
Q

Describe sensory functions of glossopharyngeal

A

The glossopharyngeal nerve transmits sensory information that conveys taste from the posterior third of the tongue.

Visceral sensory fibres of CN IX also mediate the afferent limb of the gag reflex.

34
Q

Describe gag reflex supply

A

Afferent: glossopharyngeal
Efferent: vagus

35
Q

Describe 3 things to assess on inspection of pupils

A

Size
Shape
Symmetry

36
Q

Name 3 central causes of vertigo

A

Central causes of vertigo include:

Posterior circulation stroke (POCS): acute onset vertigo, affects structures such as the brainstem or cerebellum

Multiple sclerosis (MS): demyelination of the brainstem and cerebellum

Space-occupying lesions: tumours in the posterior fossa cause compression of the brainstem and cerebellum

37
Q

How would you assess vestibular-ocular reflex

A

Explain to the patient that the test will involve briskly turning their head and then gain consent to proceed

Sit facing the patient and ask them to fixate on your nose at all times during the test

Hold their head in your hands (one hand covering each ear) and rotate it rapidly to the left, at a medium amplitude

Repeat this process, but this time turn the head to the right

In the context of a vestibular lesion, the eyes will first move in the direction of the head (losing fixation), before a corrective refixation saccade occurs.

38
Q

How would you assess jaw jerk

A

Ask the patient to open their mouth

Place your finger horizontally across the patient’s chin

Tap your finger gently with the tendon hammer

In healthy individuals, this should trigger a slight closure of the mouth.

In patients with upper motor neuron lesions, the jaw may briskly move upwards causing the mouth to close completely.

39
Q

Describe features of RAPD

A

Normally light shone into either eye should constrict both pupils equally.

When the afferent limb in one of the optic nerves is damaged, partially or completely, both pupils will constrict less when light is shone into the affected eye compared to the healthy eye.

The pupils, therefore, appear to relatively dilate when swinging the torch from the healthy to the affected eye. This is termed a relative afferent pupillary defect (RAPD).

40
Q

Describe function of hypoglossal nerve

A

The hypoglossal nerve (CN XII) transmits motor information to the extrinsic muscles of the tongue (except for palatoglossus which is innervated by the vagus nerve).

41
Q

Describe motor component glossopharyngeal nerve

A

The glossopharyngeal nerve transmits motor information to the stylopharyngeus muscle which elevates the pharynx during swallowing and speech.

42
Q

Name the muscle(s) supplied by the abducens nerve and describe the clinical features of abducens nerve palsy

A

The abducens nerve (CN VI) innervates the lateral rectus muscle.

Clinical features of abducens nerve palsy include:

Convergent squint (due to unopposed adduction)
Horizontal diplopia

43
Q

Name the muscle(s) supplied by the trochlear nerve and describe the clinical features of trochlear nerve palsy

A

The trochlear nerve innervates the superior oblique muscle.

Clinical features of a trochlear nerve palsy include:

Vertical diplopia when looking inferiorly
Torsional diplopia
Tilting of the head forwards with the chin tucked in (compensatory)

44
Q

Outline the underlying mechanism that causes a relative afferent pupillary defect (RAPD)

A

A relative afferent pupillary defect (RAPD) occurs when the afferent limb in one of the optic nerves is damaged (this can be either partially or completely).

When examining a patient with a relative afferent pupillary defect, both pupils will constrict less when light is shone into the affected eye. This failure of constriction means the pupils, therefore, appear to dilate when swinging the torch from the healthy to the affected eye, as less light is detected by the affected eye.

45
Q

Describe function of glossopharyngeal nerve

A

The glossopharyngeal nerve transmits motor information to the stylopharyngeus muscle which elevates the pharynx during swallowing and speech. The glossopharyngeal nerve also transmits sensory information that conveys taste from the posterior third of the tongue. Visceral sensory fibres of CN IX also mediate the afferent limb of the gag reflex.

46
Q

Name muscles innervated by oculomotor nerve

A

Superior rectus
Inferior rectus
Medial rectus
Inferior oblique
Levator palpebrae superioris
Sphincter pupillae

47
Q

Name 3 causes of ptosis

A

Oculomotor nerve palsy
Horner’s syndrome
Neuromuscular pathology (e.g. myasthenia gravis)

48
Q

How do you test for optic nerve

A

Inspect pupils (size, shape, symmetry)
Visual acuity (second number is variable)
Pupillary reflex: direct, consensual, swinging light test
Accommodation reflex
Test colour
Neglect
Fields
Blind spot
Fundoscopy

49
Q

3,4,6

A

Inspect eyelids
Eye movements (H test)
Pupillary reflex

50
Q

Trigeminal nerve testing summary

A

Sensory: light touch
Motor: palpate masseter and temporalis, apply resistance to opening mouth to assess pterygoids
Reflexes: Jaw jerk, corneal reflex

51
Q

Facial nerve assessment

A

Sensory: taste: ask pt if any change to taste
Ask about hearing changes (stapedius)
Inspection
Facial movements

52
Q

Vestibulocochlear nerve

A

Gross hearing assessment
Weber’s test
Rinne’s test
Vestibulo-ocular reflex

53
Q

Glossopharyngeal and vagus nerves

A

-Ask pt if changes in voice/cough/swallow
-Inspect soft palate: ask to say ‘ah’
-Ask pt to cough
-Swallow assessment
-Gag reflex

54
Q

How do you test accommodation reflex?

A

. Ask the patient to focus on a distant object (clock on the wall/light switch).

  1. Place your finger approximately 20-30cm in front of their eyes (alternatively, use the patient’s own thumb).
  2. Ask the patient to switch from looking at the distant object to the nearby finger/thumb.
  3. Observe the pupils, you should see constriction and convergence bilaterally.
55
Q

Describe blind spot

A

A physiological blind spot exists in all healthy individuals as a result of the lack of photoreceptor cells in the area where the optic nerve passes through the optic disc. In day to day life, the brain does an excellent job of reducing our awareness of the blind spot by using information from other areas of the retina and the other eye to mask the defect.

56
Q

How would you assess blind spot

A
  1. Sit directly opposite the patient, at a distance of around 1 metre.
  2. Ask the patient to cover one eye with their hand.
  3. If the patient covers their right eye, you should cover your left eye (mirroring the patient).
  4. Ask the patient to focus on part of your face (e.g. nose) and not move their head or eyes during the assessment. You should do the same and focus your gaze on the patient’s face.
  5. Using a red hatpin (or alternatively, a cotton bud stained with fluorescein/pen with a red base) start by identifying and assessing the patient’s blind spot in comparison to the size of your own. The red hatpin needs to be positioned at an equal distance between you and the patient for this to work.
  6. Ask the patient to say when the red part of the hatpin disappears, whilst continuing to focus on the same point on your face.
  7. With the red hatpin positioned equidistant between you and the patient, slowly move it laterally until the patient reports the disappearance of the top of the hatpin. The blind spot is normally found just temporal to central vision at eye level. The disappearance of the hatpin should occur at a similar point for you and the patient.
  8. After the hatpin has disappeared for the patient, continue to move it laterally and ask the patient to let you know when they can see it again. The point at which the patient reports the hatpin re-appearing should be similar to the point at which it re-appears for you (presuming the patient and you have a normal blind spot).
  9. You can further assess the superior and inferior borders of the blind spot using the same process.
57
Q

Describe uvula deviation

A

Inspect the palate and uvula which should elevate symmetrically, with the uvula remaining in the midline. A vagus nerve lesion will cause asymmetrical elevation of the palate and uvula deviation away from the lesion.

58
Q

Describe abnormal cough assessment

A

Vagus nerve lesions can result in the presence of a weak, non-explosive sounding bovine cough caused by an inability to close the glottis.

59
Q

Describe abnormal swallow assessment

A

Ask the patient to take a small sip of water (approximately 3 teaspoons) and observe the patient swallow. The presence of a cough or a change to the quality of their voice suggests an ineffective swallow which can be caused by both glossopharyngeal (afferent) and vagus (efferent) nerve pathology.

MRCS B Examinations and practical skills (13 decks)

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