Cranial nerves examination

Question 1

Cranial nerve I

Answer 1

• I - Olfactory
  
  • Have you noticed any change in your sense of smell recently?
  • Are you able to smell when your dinner’s ready?

Question 2

Cranial nerve II

Answer 2

• II - Optic
  
  • Visual acuity (Snellen chart)
    
    • Wear glasses if required
    • Do one eye at a time
  • Visual fields
    
    • Test all 4 quadrants of each eye separately
    • Ask patient to detect wiggling finger
    • Cover own eye, get down to their level
  • Pupillary constriction
    
    • Direct
    • Consensual
  • Fundoscopy
    
    • Optic neuritis
    • Papilloedema

Question 3

Cranial nerves III, IV, VI

Answer 3

*H-test and convergence*

• III - Occulomotor
  
  • All (other) extraoccular muscles
  • Eyelids (ptosis)
• IV - Trochlear
  
  • Superior oblique
    
    • Normal: down and out
    • Abnormal: up and in
• VI - Abducens
  
  • Lateral rectus
    
    • Normal: lateral
    • Abnormal: medial

Question 4

Cranial nerve V

Answer 4

• V - Trigeminal
  
  • Sensation
  • Motor
    
    • Muscles of mastication (paralysis on ipsilateral side)
      
      • Feel temple and mastoid process while patient clenches teeth
      • Open jaw against resistance

Question 5

Cranial nerve VII

Answer 5

• VII - Facial
  
  • Sensation
    
    • Taste on anterior 2/3 of tongue
  • Motor
    
    • Muscles of facial expression (against resistance)
      
      • Clench eyes
      • Lift eyebrows
      • Smile
      • Puff out cheeks

Question 6

Cranial nerve VIII

Answer 6

• VIII - Vestibulocochlear
  
  • Questions
    
    • Did your child pass the hearing test at birth?
    • Does he have the television particularly loud?
    • Can you hear your teacher from the back of the classroom?
  • Weber’s test
    
    • PLace vibrating tuning fork on the forehead
    • If sound is lateralised to one side there is either:
      
      • Conductive hearing loss on the same side
      • Sensineural loss on the other side (Rinne’s to confirm)
  • Rinne’s test (air vs bone conduction)
    
    • Place a vibrating tuning fork of n the mastoid process
    • Place in front of the ear - Which is louder?
      
      • Air = normal
      • Bone = conductive hearing loss

Question 7

Cranial nerve IX & X

Answer 7

• IX - Glossopharyngeal
  
  • Sensory (taste posterior 1/3)
  • Motor (stylopharyngeus)
• X - Vagus
  
  • Motor (palate and vocal cords)
    
    • Say ‘Ahhh’
    • Say ‘Silly sausages’
    • Swallow
    • Cough

Question 8

Cranial nerve XI

Answer 8

• XI - Accessory
  
  • Trapezius
    
    • Shrug shoulders against resistance
  • Sternocleidomastoids
    
    • Turn head against resistance

Question 9

Cranial nerve XII

Answer 9

• XII - Hypoglossal
  
  • Tongue movements (deviates to affected side)