2. Cranial Nerves 12 pairs PNS You must know: The name The number
The order
The function
S/M
How to assess

4. Cranial Nerves Names of nerves
On old olympus’ towering tops a Finn and German viewed some Hops
Olfactory Optic Oculomotor
Trochlear Trigeminal Abducens
Facial Acoustic Glaossopharyngeal
Vagus Spinal accessory Hypoglossal

5. Cranial Nerves Classification by Function Sensory,Motor or Both
Some say marry money but my brother says bad business marry money
Olfactory S Optic S Oculomotor M
Trochlear M Trigeminal B Abducens M
Facial B Acoustic S
Glossopharyngeal B Vagus B
Spinal accessory M Hypoglossal M

6. Cranial Nerves Number -1 Name: Olfactory Sensory Function Assessment
Sense of smell
Assessment
Identify familiar odor

7. Cranial nerves – 1 Olfactory Sense of smell Rarely formally tested
Ask directly
Bedside foodstuffs

8. Olfactory “Have you had any change in your sense of smell recently?”
Can use coffee/orange smells to see if correctly identified.
Not routinely examined in clinical practice.

9. Cranial nerves – 2 Optic Visual acuity Visual fields
Snellen chart, newspaper
Visual fields
Direct light reflex
(Consensual light reflex)

10. Cranial Nerves Number -2 Name: Optic Sensory Function Assessment
Visual Acuity
Assessment
Snellen eye chart

11. Pupil
Retina
Optic nerve
III
Optic chiasm
Lateral geniculate bodies
Ciliary ganglion
Edinger-Westfahl nucleus
Pretectal nucleus

12. P L R Visual fields Bitemporal hemianopia RIGHT homonymous hemianopia
Retina
Optic nerve
Optic chiasm P
Bitemporal hemianopia
Optic radiation
RIGHT homonymous hemianopia

13. Examples of How to Examine

14. Pupil Abnormalities
Asymmetry of pupil size of >1mm suggests CN III compression
Bilateral dilation suggests anoxia or drug affect
Unilateral constriction is seen with sympathetic dysfunction (Horner syndrome) or carotid artery dissection
Bilateral constriction is seen with:
Pontine hemorrhage
Drugs (opiates, Clonidine)
Toxins (organophosphates)

15. Cranial Nerves Number -3 Name: Oculomotor Motor Function Assessment
Muscles the move the eye, lid, papillary constriction, lens accommodation
Assessment
Test for ocular rotation, nystagmus, Papillary reflexes, check for ptosis

16. Oculomotor, Abducens and Trochlear
“Keeping you head perfectly still, follow my finger with your eyes.”
Make a H pattern with your finger.
“Do you see double anywhere?”
Look for nystagmus.

18. Nystagmus:
Involuntary osculation of the eyeball

19. Ptosis
Drooping eyelid

20. Ptosis

24. Papillary reflexes
Pupil changing in size when exposed to light

26. VI nerve palsy

28. Cranial Nerves Number -5 Name: Trigeminal Sensory & Motor Function
Facial sensation, corneal reflex, mastication
Assessment
Distinguish between sharp and dull on face
Check blink reflex
Have patient clinch and move jaw from side to side, feel jaw strength

29. Trigeminal Nerve Two parts: Assess sensation to face
Sensory to face
Motor to muscles of mastication
Assess sensation to face
Determine if patient can open mouth.
“Clench your teeth” - feel for muscle bulk at Masseters

30. V1 - Opthalmic
V2 - Maxillary
V3 - Mandibular

33. Cranial Nerves Assessment
Number - 7
Name: Facial
Sensory & Motor
Function
Facial expression and muscle movement
Salivation and tearing
Taste
Sensation in the ear
Assessment
Observe for symmetry while pt performs facial movement
Stick out tongue
Distinguish between sugar and salt

34. Facial Nerve Must assess at least 3 muscle groups
“Raise your eyebrows”
“Show me your teeth”
“Puff out your cheeks”

35. VII. Facial UMN paralysis-Only lower face affected
Stroke
LMN paralysis-All of face affected
Bells Palsy

37. Bell’s Palsey. What side is affected?
Can she wrinkle her forehead on the right?

41. Central VII
Peripheral VII

45. Bell’s palsy Symptoms of Bell's palsy may include:
Numbness, mild weakness or complete paralysis on one side of the face;
A droopy face on one side, with difficulty making facial expressions, smiling on that side or closing the eye on that side of the face;
Drooling;
Pain in or behind your ear or around the jaw on the affected side;
Increased sensitivity to sound;
Excessive tearing in the eye or dry eye;
Headache or neck pain;
Loss of the ability to taste.

46. Cranial Nerves Number -8 Name: Acoustic Sensory Function Assessment
Hearing & equilibrium
Assessment
Simple hearing test

47. Cranial Nerves Number -9 Name: Glossopharyngeal Sensory & Motor
Function
Taste
Sensation in pharynx and tongue
Pharyngeal muscles
Assessment
Ability to discriminate btw sugar and salt

48. Cranial Nerves Palate and Tongue: Glossopharyngeal (IX),Vagus (X)
Ask patient to say “ah”
Ask the patient to say “ah”. The palate should move upwards symmetrically.
Asymmetry of movement may be associated with dysarthria and dysphagia. Swallowing difficulties can be associated with aspiration after stroke.

49. Glossopharyngeal and Vagus
Open your mouth.
Say “arrgh”
Look at palatal movement. Deviates AWAY from affected side.
Assess gag reflex - not routinely done

50. Cranial Nerves Number -11 Name: Accessory Motor Function Assessment
Shoulder movement
Assessment
Strength of muscle, shrug

51. Accessory
Put hand on one cheek, “push me away”, and feel sternocleidomastoid bulk on opposite side.

52. Cranial Nerves Number -12 Name: Hypoglossal Motor Function Assessment
Tongue movement
Assessment
Check tongue strength and movement

53. Hypoglossal “Stick out your tongue”
Look for deviation TOWARDS affected side.
Can assess power, but only if deficit found on gross examination.