Cranial Nerves

Question 1

Cranial nerve 1 - Olfactor nerve

Answer 1

Sensory nerve - SMELL
- Start by asking questions related smell
- Smell test = give patient things to smell (coffee, mint etc), test unilaterally

Question 2

Cranial nerve 2 - optic nerve

Answer 2

Sensory nerve - SIGHT
- Start by asking questions related to sight (double vision, bluriness, lack of peripheral vision)
- Visual fields test = patient covers 1 eye and practitioner covers other eye, use finger to test the vision in the patients temporal field and then the nasal field by doing hand movements at the edge of field and asking patient to point them out

Question 3

Cranial nerve 3 - Oculomotor nerve

Answer 3

Motor and Parasympathetic nerve - RESPONSIBLE FOR EYE MOVEMENT AND PUPIL CONTROL
- Pupillary reflex test - gently point light into one eye, then withdraw light for a few seconds, followed by stimulating the same eye again but this time observe the indirect, or consensual, PLR in opposite eye
CN2 lesion - loss of consensual PLR
CN3 lesion - loss of direct PLR
- H Test

Question 4

Cranial nerve 4 - trochlear nerve

Answer 4

Motor nerve - INNOVATES SUPERIOR OBLIQUE MUSCLE (moves eye downward and inward)
H test - this tests cranial nerve 3, 4, and 6

Question 5

Cranial nerve 5 - trigeminal nerve

Answer 5

Multifunctional nerve - SENSORY FOR MANDIBULAR, MAXILLARY AND OPTHALMIC ZONES and motor branches INNERVATE JAW MUSCLES
For motor branch - palpate jaw and ask patient to chew

Question 6

Cranial nerve 6 - abducens nerve

Answer 6

Motor nerve - INNERVATES LATERAL RECTUS MUSCLE which is responsible for moving eye laterally
H test

Question 7

Cranial nerve 7 - facial nerve

Answer 7

Sensory and motor functions - FACIAL EXPRESSIONS and CONVEYS TASTE SENSATIONS from 2/3 of front of tongue to brain
Test - ask patient to smile, scrunch face, and blow out cheeks

Question 8

Cranial nerve 8 - vestibulocochlear nerve

Answer 8

Special sensory nerve - made up of VESTIBULAR nerve (balance and equilibrium) and COCHLEAR nerve (hearing)
Webers test - 512hz tuning fork on centre of forehead
Rinners test - 512hz tuning fork on mastoid process (tests for bone conduction)
Then spin around and place next to ear that tests for air conduction
Sensory neural hearing far better than bone conduction

Question 9

Cranial nerve 9 - glossopharyngeal nerve

Answer 9

Motor, sensory and parasympathetic nerve - ENABLES SWALLOWING
- Ask patient to cough
Swallowing test - ask patient to sip water
Uvula deviation test - get patient to “Ah”, palate will elevate with deviation of base of uvula away from side of lesion

Question 10

Cranial nerve 10 - vagus nerve

Answer 10

Motor, sensory and parasympathetic nerve - CONTROLS HEART, LUNGS AND DIGESTIVE TRACT
- ask patient to cough
Swallowing test - ask patient to sip water
- Uvula deviation test - patient says “Ah”, palate will elevate with deviation of base of uvula away from side of lesion

Question 11

Cranial nerve 11 - accessory nerve

Answer 11

Motor nerve - CONTROLS MOVEMENT OF THE TRAPEZIUS, SCM and PHARYNX
- trapezius and SCM muscle test (looking for neurological deficit)

Question 12

Cranial nerve 12 - hypoglossal nerve

Answer 12

Motor nerve - CONTROLS TONGUE AND THROAT MUSCLES
- Test for tongue protrusions
- Resist tongue movements