1. Cranial Nerve Evaluation
Dr. Michael P. Gillespie

2. Brain Stem Between the brain and spinal cord. 3 regions.
Medulla oblongata.
Pons.
Midbrain.
Dr. Michael P. Gillespie

3. Medulla Oblongata A continuation of the spinal cord.
Sensory (ascending) tracts and motor (descending) tracts travel through the white matter of the medulla.
Many nerves decussate (cross over) in the medulla.
Dr. Michael P. Gillespie

4. Medulla Oblongata
Cardiovascular center regulates the heartbeat and the diameter of the blood vessels.
Dr. Michael P. Gillespie

5. Medulla Oblongata
The medullary rhythmicity area adjusts the rhythm of the breathing and controls reflexes for vomiting, coughing, and sneezing.
Dr. Michael P. Gillespie

6. Medulla Oblongata
The nuclei for the following cranial nerves reside in the medulla:
VIII (vestibulocochlear).
IX (glossopharyngeal).
X (vagus).
XI (accessory).
XII (hypoglossal).
Dr. Michael P. Gillespie

7. Pons Pneumotaxic area and apneustic area regulate breathing.
Nuclei for cranial nerves V (trigeminal), VI (abducens), and VII (facial).
Dr. Michael P. Gillespie

8. Midbrain
The midbrain or mesencephalon contains the superior colliculi (visual actvities) and inferior colliculi (auditory pathways).
The midbrain contains the substantia nigra which release dopamine to help control subconscious muscle activities. Loss of these neurons results in Parkinson disease.
Cranial nerves III (oculomotor) and IV (trochlear) originate here.
Dr. Michael P. Gillespie

9. Dr. Michael P. Gillespie

10. Dr. Michael P. Gillespie

11. Dr. Michael P. Gillespie

12. Dr. Michael P. Gillespie

13. Dr. Michael P. Gillespie

14. Cranial Nerve I - Olfactory
Type: sensory.
Function: smell.
Anosmia – loss of sense of smell.
Does not connect with the brainstem.
Dr. Michael P. Gillespie

15. Dr. Michael P. Gillespie

16. Cranial Nerve II – Optic Nerve
Type: sensory.
Function: vision.
Anopia – blindness in one or both eyes.
Dr. Michael P. Gillespie

17. Cranial Nerve III - Oculomotor
Type: mixed (mainly motor).
Function: movement of the upper eyelid and eyeball. Accomodation of the lens for near vision and constriction of the pupil.
Strabismus – deviation of the eye in which both eyes don’t focus on the same object.
Ptosis – drooping of the upper eyelid.
Diploia – double vision.
Dr. Michael P. Gillespie

18. Cranial Nerve IV – Trochlear Nerve
Type: mixed (mainly motor).
Function: movement of the eyeball.
Diplopia and strabismus occur with trochlear nerve damage.
Dr. Michael P. Gillespie

19. Dr. Michael P. Gillespie

20. Cranial Nerve V – Trigeminal Nerve
Type: mixed.
Function: conveys impulses for touch, pain, temperature and proprioception. Chewing.
Trigeminal neuralgia (tic douloureux) – pain to branches of the trigeminal nerve.
Dentists apply anesthetic to branches of this nerve.
Dr. Michael P. Gillespie

21. Dr. Michael P. Gillespie

22. Cranial Nerve VI - Abducens
Type: mixed (mainly motor).
Function: movement of the eyeball.
With damage to this nerve the eye cannot move laterally beyond the midpoint and usually points medially.
Dr. Michael P. Gillespie

23. Dr. Michael P. Gillespie

24. Cranial Nerve VII – Facial Nerve
Type: mixed.
Function: Propriception and taste. Facial expression. Secretion of saliva and tears.
Injury produces bell’s palsy (paralysis of facial muscles).
Dr. Michael P. Gillespie

25. Dr. Michael P. Gillespie

26. Cranial Nerve VIII – Vestibulocochlear Nerve
Type: mixed (mainly sensory).
Function: conveys impulses for equilibrium and hearing.
Injury can cause vertigo, ataxia (muscular incoordination), nystagmus (rapid movement of the eyeball), and tinnitus.
Dr. Michael P. Gillespie

27. Cranial Nerve IX – Glossopharyngeal Nerve
Type: mixed.
Function: taste and somatic sensations from the posterior 1/3 of the tongue. Elevates the pharynx during swallowing and speech. Stimulates the secretion of saliva.
Injury causes decreased salivary secretion, loss of taste, and difficulty swallowing.
Dr. Michael P. Gillespie

28. Dr. Michael P. Gillespie

29. Cranial Nerve X – Vagus Nerve
Type: mixed.
Function: taste and somatic sensations. Swallowing, coughing, and voice production. Regulates GI tract and heart rate.
Injury interferes with swallowing, paralyzes vocal cords, and causes the heart rate to increase.
Dr. Michael P. Gillespie

30. Dr. Michael P. Gillespie

31. Cranial Nerve XI – Accessory Nerve
Type: mixed (mainly motor).
Function: Proprioception. Swallowing, movement of head and shoulders.
If the nerves are damaged the SCM and Trapezius become paralyzed.
Dr. Michael P. Gillespie

32. Dr. Michael P. Gillespie

33. Cranial Nerve XII – Hypoglossal Nerve
Type: mixed (mainly motor).
Function: Proprioception. Movement of the tongue during speech and swallowing.
Injury results in difficulty in chewing, speaking, and swallowing. When protruded, the tongue curls towards the affected side and atrophies on the affected side.
Dr. Michael P. Gillespie

34. Dr. Michael P. Gillespie

35. Cranial Nerves I – Olfactory II – Optic III – Oculomotor
IV – Trochlear
V – Trigeminal
VI – Abducens
VII – Facial
VIII – Auditory (Vestibulocochlear)
IX – Glossopharyngeal
X – Vagus
XI – Spinal accessory
XII - Hypoglossal
Dr. Michael P. Gillespie

36. Cranial Nerves
On Old Olympus’ Towering Tops A Fin And German Viewed Some Hops.
This mnemonic device helps you memorize the names of the cranial nerves.
The first letter from each word corresponds to the first letter of each cranial nerve.
Dr. Michael P. Gillespie

37. Cranial Nerves
Some Say Marry Money, But My Brother Says Big Brains Matter Most.
This mnemonic device helps you memorize the sensory / motor distribution of the cranial nerves.
S = sensory
M = Motor
B = Both
Dr. Michael P. Gillespie

38. Cranial Nerves
Twelve pairs of cranial nerves exit from the brain and brainstem.
These nerves innervate the face, head, and neck.
They control all sensory and motor functions in these areas including the special senses of vision, hearing, smell, and taste.
Cranial trauma, infections, aneurysm, stroke, degenerative diseases (i.e. multiple sclerosis), upper motor neuron lesions, lower motor neuron lesions, increased intracranial pressure, and abnormal masses or tumors can all affect the cranial nerves.
Dr. Michael P. Gillespie

39. Unilateral and Bilateral Innervation
Some facial movements are performed in bilateral synchrony such as swallowing and moving the forehead and are thus innervated bilaterally.
Fine movements of the face are unilateral. The contralateral hemisphere innervates the affected area.
Dr. Michael P. Gillespie

40. Olfactory Nerve (I) Testing
To test this nerve, obtain some aromatic substance such as coffee, tobacco, or peppermint oil.
Instruct the patient to close one nostril.
Place the substance under the open nostril and ask what the patient smells if anything.
Repeat the procedure for the opposite nostril.
Dr. Michael P. Gillespie

41. Olfactory Nerve (I) Testing
Dr. Michael P. Gillespie

42. Olfactory Nerve (I) Testing
If the patient cannot smell or identify the smell unilaterally, suspect a lesion of the olfactory nerve.
If the patient cannot smell or identify the smell bilaterally, consider a nonorganic problem or a bilateral cranial nerve I lesion.
Dr. Michael P. Gillespie

43. Olfactory Nerve (I) Testing
A diminished or almost absent sense of smell is common in the elderly. This will be apparent if the loss of sense of smell is bilateral and the cranium has not undergone a trauma.
Other nonneurogenic lesions such as a sinus infection, deviated septum, and lesions caused by smoking nay also cause a loss of smell.
Dr. Michael P. Gillespie

44. Optic Nerve (II) Testing
The optic nerve is responsible for visual acuity and peripheral vision.
To test for visual acuity, ask the patient to cover one eye and read the smallest print possible on a Snellen chart.
Repeat the test with the opposite eye.
This is not a test for visual acuity and refractive errors of the eye. We are testing the acuity for optic nerve involvement. Consequently, we can perform the test with the patient wearing glasses or contact lenses.
Dr. Michael P. Gillespie

45. Optic Nerve (II) Testing
To test for peripheral vision, ask the patient to cover one eye with the hand and keep a fixed gaze on your nose with the uncovered eye.
Directly motion a large cross with your finger from superior to inferior and from right to left.
Instruct the patient to tell you when he or she begins to see your finger.
Repeat with the opposite eye.
Record results.
Dr. Michael P. Gillespie

46. Optic Nerve (II) Testing
Any loss of vision from a complete unilateral or bilateral loss of vision, loss of half fields of vision (hemianopsia), or a partial defect in the field of vision (scotoma) indicates an optic nerve lesion.
A temporal lobe lesion can produce a superior contralateral quadrantanopsia.
An occipital lobe lesion can produce a contralteral homonymous hemianopsia with macula sparing.
Dr. Michael P. Gillespie

47. Optic Nerve (II) Testing
Dr. Michael P. Gillespie

48. Oculomotor (III), Trochlear (IV) & Abducens (VI) Nerve Testing
Cranial nerves III, IV, and VI are all associated with ocular and pupillary motility.
They are testing together for simplicity.
Cranial nerve II also innervates the levator palpebrae muscles, which are responsible for movement of the eyelids.
Dr. Michael P. Gillespie

49. Oculomotor (III), Trochlear (IV) & Abducens (VI) Nerve Testing
First, look at your patient and observe for any ptosis.
Next inspect the eye globes for alignment.
Next, inspect the pupils and determine their size and shape.
Dr. Michael P. Gillespie

50. Oculomotor (III), Trochlear (IV) & Abducens (VI) Nerve Testing
Test the pupillary reflex by flashing a light into one of the patient’s eyes. Look at the pupils one at a time for dilation and contraction.
Test ocular movements. Have the patient follow either your finger or a moving object through the entire field of vision in all axes.
Observe for nystagmus and / or the inability to move the eye on a particular direction.
Test for convergence by having the patient look at a distant object and continue to focus on it as you move it closer to the patient.
Dr. Michael P. Gillespie

51. Oculomotor (III), Trochlear (IV) & Abducens (VI) Nerve Testing
Oculomotor nerve lesion
Causes ptosis of the eyelid with inability to open the lid.
Eye alignment may be down and lateral.
The patient will be unable to move the eyeball upward, inward, or downward due to weakness of the medial, superior, and inferior rectus muscles.
Pupil is usually dilated and the pupillary reflex is absent.
The most frequent cause is an aneurysm in the circle of Willis.
Dr. Michael P. Gillespie

52. Oculomotor (III), Trochlear (IV) & Abducens (VI) Nerve Testing
Trochlear nerve lesion
Causes superior and lateral deviation of the eye with inability to move the eyeball downward and inward because of weakness of the superior oblique muscle.
Aducens nerve lesion
Causes inability to move the eyeball outward because of weakness of the lateral rectus muscle.
Dr. Michael P. Gillespie

53. Trigeminal Nerve (V)
The trigeminal nerve is composed of motor and sensory portions.
The motor portion innervates the muscles of mastication (masseter, pterygoid, and temporal muscles).
The sensory portion is divided into three branches: opthalmic (V1), maxillary (V2), and mandibular (V3).
Dr. Michael P. Gillespie

54. Trigeminal Nerve (V) Motor
Masseter – instruct the patient to simulate a bite while you palpate the masseter and attempt to open the patients jaw with your thumbs.
Pterygoid – instruct the patient to deviate the jaw against your resistance.
Temporalis – instruct the patient to clench the jaw while you palpate the temporalis with your fingers.
Dr. Michael P. Gillespie

55. Trigeminal Nerve (V)
A weak masseter or pterygoid may indicate a trigeminal nerve lesion. A difference in tension in the temporalis may indicate a lesion.
In b/l paralysis, the jaw may not close tightly.
In unilateral paralysis, the jaw deviates towards the side of the lesion.
Dr. Michael P. Gillespie

56. Trigeminal Nerve (V) Reflex
Corneal reflex – instruct the patient to gaze upward and inward while you touch the cornea with a strand of cotton, approaching from the lateral side. Do not touch the eyelash or conjunctiva.
The patient should blink when the cornea is touched.
Sensory from trigeminal nerve, from the facial nerve.
Jaw reflex – instruct the patient to open the mouth slightly. Place your thumb or index finger just lateral to the midline. Tap down to open the jaw with your reflex hammer.
The patient should close the jaw rapidly.
Sensory and motor from trigeminal nerve.
Dr. Michael P. Gillespie

57. Trigeminal Nerve (V) Sensory
Patient eyes closed. Touch the forehead, cheek, and chin with a pin for pain sensation; a piece of cotton for the sensation of light touch; small test tubes of hot an cold water for thermal sensations. Compare b/l.
Touch the tongue, inside of both cheeks, and the hard palate with a tongue depressor. Have the patient give a signal upon feeling the sensation.
Decreased sensation indicates a lesion of that sensory branch of the trigeminal nerve in the affected region.
Dr. Michael P. Gillespie

58. Trigeminal Nerve (V)
Dr. Michael P. Gillespie

59. Facial Nerve (VII) Motor
The facial nerve has both motor and sensory fibers.
The motor fibers innervate the muscles of the face and the platysma.
Observe for abnormal movements, tics or tremors. Note the degree of change or lack of change of expression.
Observe the face in repose. Instruct the patient to frown, raise the eyebrows, close the eyes, show the teeth, smile, and whistle or puff the cheeks.
Dr. Michael P. Gillespie

60. Facial Nerve (VII) Sensory
Instruct the patient to close the eyes and protrude the tongue. Apply solutions of sugar, salt, and/or vinegar to one side and on the anterior two-thirds of the tongue. Ask the patient to identify each substance without retracting the tongue (point to a list). Rinse the mouth and apply on opposite side.
Dr. Michael P. Gillespie

61. Facial Nerve (VII)
Dr. Michael P. Gillespie

62. Vestibulocochlear Nerve (VIII)
Weber’s Test: Cochlear Nerve
Place a tuning fork on top of the patient’s head. Ask if the patient hears it the same in both ears. If it is louder in one side than the other suspect a conduction problem. If it is heard only in one side, suspect a cochlear nerve lesion.
Rinne’s Test: Cochlear Nerve
Place a vibrating tuning fork on the mastoid process. Ask the patient to say when the sound disappears. After the sound disappears place the tuning fork next to, but not touching the ear. See when the sounds fades out.
Normally, air conduction is twice as loud as bone conduction (Rinne positive). In conduction lesions and non-neurogenic lesions, bone conduction is greater than air conduction (Rinne negative).
Dr. Michael P. Gillespie

63. Vestibulocochlear Nerve (VIII)
Dr. Michael P. Gillespie

64. Vestibulocochlear Nerve (VIII)
Veering Test: Vestibular nerve
Instruct the patient to walk with eyes closed.
Veering on walking or a positive Romberg’s test indicates a unilateral vestibular lesion.
Dr. Michael P. Gillespie

65. Vestibulocochlear Nerve (VIII)
Dr. Michael P. Gillespie

66. Glossopharyngeal and Vagus Nerves (IX, X)
Sensory
Patient closes eyes and protrudes tongue. Apply a bitter tasting solution to the posterior third of the tongue. Have the patient identify each substance without retracting the tongue.
Reflex (Gag reflex)
With a throat stick, touch the posterior pharyngeal wall, first on one side, then on the other. Observe the moment when the patient gags and ask him whether the sensation is stronger on one side or the other.
Dr. Michael P. Gillespie

67. Glossopharyngeal and Vagus Nerves (IX, X)
Dr. Michael P. Gillespie

68. Spinal Accessory Nerve (XI)
The spinal accessory nerve innervates the trapezius and the sternocleidomastoid muscles. To test the nerve, test these muscles.
Trapezius
Patient seated, apply pressure to the patient’s shoulders bilaterally and ask him to shrug against resistance.
SCM
Patient seated, place your hand on the lateral aspect of the patient’s jaw, instruct him to turn the head toward your hand against resistance.
Dr. Michael P. Gillespie

69. Spinal Accessory Nerve (XI)
Dr. Michael P. Gillespie

70. Hypoglossal Nerve (XII)
The hypoglossal nerve is purely motor and is responsible for movement of the tongue.
Place your hand on the patient’s cheek and instruct him to press the tip of the tongue against the cheek under your hand. Repeat b/l. Instruct the patient to protrude the tongue.
If the pressure is unequal, suspect a unilateral hypoglossal nerve lesion. The tongue will deviate towards the side of the lesion.
Dr. Michael P. Gillespie

71. Hypoglossal Nerve (XII)
Dr. Michael P. Gillespie