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Flashcards in Cranial nerve Examination Deck (30)
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1
Q

What are the cranial nerves

A

12 pairs of nerves that emerge from brainstem and supply head and neck

sensory, motor and parasympathetic activity

Numbered 1-12

2
Q

CN abnormalities

A

Cranial nerve abnormalities may arise from lesions affecting the;

  • communicating pathways to and from the cortex, cerebellum and other parts of the brain stem
  • nerve nucleus
  • nerve
  • neuromuscular junction disorders
  • Muscle
3
Q

Mnemonic for cranial nerves

A

Oh oh oh to touch and feel Virgin girls vagina and hymen

some say marry money but my brother says big brains matter most

4
Q

Olfactory

A

Sensory
smell
tract: olfactory cells of nasal mucosa –> olfactory bulbs –> pyriform cortex

5
Q

Optic nerve

A

Sensory
Vision
Tract: retinal ganglion cells –> optic chasm –> thalamus –> primary visual cortex in occipital lobe

6
Q

Muscles of the eye

A

Superior, inferior, medial and lateral rectus muscles

superior and inferior oblique

7
Q

Which cranial nerves innervate the eye muscles

A

Oculomotor, trochlear Abducens

8
Q

Oculomotor innerveates which muscles

A

all apart from lateral rectus and superior oblique

9
Q

Oculomotor

A

Motor function - innervates muscles and upper eyelet

parasympathetic function - constrict the pupils

10
Q

3rd nerve palsy

A

lateral rectus - laterally
superior oblique - down

Down and out + ptosis (parasympathetic innervation)

11
Q

Medical 3rd nerve palsy

A

pupil sparing

microvascular change on uncles or 3rd nerve pathway

12
Q

Surgical 3rd nerve palsy

A

pupillary dilation

parasympathetic fibres run on outside of oculomotor nerves

something that presses on the nerve ( causes the pupil to dilate)

13
Q

Trochlear nerve innervates

A

Superior oblique muscles

14
Q

Trochlear nerve

A

motor
moves the eyeball
nucleus location: midbrain

depresses the adducted eye and intorts the abducted eye

longest intracranial course are II and IV are only nerves to decussate to contralateral side

15
Q

Trochlear nerve lesions (4th nerve palsy)

A

Double vision when eye looking down (superior oblique moves the eye down)

When looking down at the paper or looking down the stairs

16
Q

abducens Nerve

A

motor
eyeball movement
nucleus: pons
Structure innervated : lateral rectus

17
Q

6th nerve palsy

A

horizontal double vision that is corrected in the primary position

18
Q

Causes of 6th nerve palsy

A
Vasculitis ( DM and HTN) 
Raised ICP (due to turning  junction)
19
Q

Causes of 4th nerve palsy

A
  • vasculitis (HTN and DM)
  • tumour
  • trauma
  • congenital

superior oblique

20
Q

3rd nerve palsy causes

A

Vasculitis (HTN and DM)

Aneurysm (berry aneurysm of circle of wills)

21
Q

Internuclear ophthalmoplegia

A

disorder of conjugate gaze
-failure of adduction of affected eye with nystagmus on lateral gaze in contralateral eye

Can be unilateral or bilateral
Results from lesion of medial longitudinal fasiculus (connects 3rd and 6th nerve nuclei)

Commonly seen in multiple sclerosis

22
Q

Horner syndrome

A

consists of:

  • ptosis (drooping of the eyelid)
  • miosis (constriction of the pupil)
  • enopthlamosis (posterior displacement of the eyeball shruken)
  • anhidorsis (not able to sweat properly)

From ipsilateral disruption of cervical/thoracic sympathetic chain

23
Q

Trigeminal nerve

A

sensory input from face
nucleus: Pons and medulla
structure innervated: face (ophthalmic, mandibular and maxillary division) and touch pain pressureto anterior 2/3rds of the tongue

Motor 
Mastication 
nucleus location: pons 
Structure innervated: 
Muscles of mastication (master, temporalis, medial and lateral pterygoids
24
Q

Herpes zoster opthalmicus

A
pain may priced vesicles 
lifetime risk 1% 
V2/v3 rarely affected 
elderly and immunocompromised 
treated with oral acyclovir
25
Q

Facial nerve

A

Motor
nucleus location: Pons
Function: muscles of facial expression

Sensory 
nucleus location: medulla 
Function: 
Taste 
structure innervated: anterior 2/3rd tongue 

parasympathetic
nucleus location: Medulla
Function: salivation and lacrimation
Structure innervated: salivary and lacrimal glands

26
Q

Lower facial weakness

A

both upper and lower

27
Q

Upper facial weakness

A

Upper part has dual innervation therefore only lower affected

28
Q

Corneal reflex

A

combines facial sensation and facial power

lightly touch cornea with cotton wool
-afferent - V
-efferent -VII
Test of pontine function

29
Q

Vestibulocochlear nerve

A

Sensory
balance
pons and medulla
structure innervated: nerve endings within semi-circular canals –> cerebellum and spinal cord

Sensory
hearing
nucleus: pons and medulla
Structure innervated: cochlear–> auditory cortex in the temporal lobes

30
Q

Glossopharyngeal

A

t