Cranial Nerves

Question 1

How many pairs of cranial nerves are there?

Answer 1

12 pairs

Question 2

What are the 12 cranial

Answer 2

Olfactory
Optic
Oculomotor
Trochlear
Trigeminal
Abducent
Facial
Vestibulocochlear
Glossopharyngeal
Vagus
Accessory
Hypoglossal

Question 3

Primary function of the olfactory CN

Answer 3

smell

Question 4

Primary function of the optic CN

Answer 4

vision

Question 5

Primary function of the oculomotor CN

Answer 5

eyelid opening, eyeball motion up and down

Question 6

Primary function of the Trochlear CN

Answer 6

Eye motion up and down

Question 7

Branches of the trigeminal nerve

Answer 7

-ophthalmic
-Maxillary
-Mandibular

Question 8

Primary function of the trigeminal CN

Answer 8

-TMJ/jaw movements and senssation
-Forehead movements; facial movements
-Cheeks

Question 9

Primary function of the abducent CN

Answer 9

Eye movements outward (abduction)

Question 10

Primary function of the facial CN

Answer 10

Facial expression (kissy face, puffer face, pout face)
Hyoid elevation
Salivary glands
Mandibular depression

Question 11

Primary function of vestibulocochlear CN

Answer 11

Balance & hearing

Question 12

Primary function of the glossopharyngeal CN

Answer 12

Pharyngeal constrictors
Pharyngeal muscles moving it up and down
Taste/sensation posterior 1/3 of tongue

Question 13

Primary function of the vagus CN

Answer 13

Taste receptor in posterior oral cavity
Laryngeal muscles

Question 14

Primary function of the accessory CN

Answer 14

Neck and shoulder movements

Question 15

Primary function of the hypoglossal CN

Answer 15

tongue movements

Question 16

How to assess the oculomotor nerve (CN 3)

Answer 16

Look for eyelid drooping
Pt moves eyes up, down, inward

Question 17

How to assess trochlear nerve (CN 4)

Answer 17

Pt looks towards nose
Pt looks up and down

Question 18

How to assess trigeminal nerve (CN 5)

Answer 18

Cotton swab test or pinprick test- touch lower gum and mandible
Tongue anterior tongue on both sides
Observe masseter at rest, observe chewing, bite down
Pt avoids mouth forced open, then avoids mouth forced closed
Pt protrudes jaw out

Question 19

how to assess facial nerve (CN 7)

Answer 19

Have pt make facial expressions: wrinkle forehead when looking up, raise eyebrows, kissy face, puffer fish face (maintain air seal), show teeth
Cotton swab test with taste on front of tongue

Question 20

How to assess glossopharyngeal nerve (CN 9)

Answer 20

Contributes to cough reflex
Cotton swab vs tongue depressor tonguing posterior tongue– ask pt if material is hard and soft
Cotton swabs with taste on the back of tongue
Say /ah/ and look for palatal movement

Question 21

How to assess vagus nerve (CN 10)

Answer 21

Observe gag reflex
Listen for resonance voice problems
Cough hard and test for glottal closure
Hold phonation and listen for problems in voice: gurgle, wet, breathy, hoarse, stridor, monopitch, tremor
Test /k and g/ sounds to test hard palate
observe swallowing and palate for reduced elevation and delay in swallowing response
Say /ah/ and look for palatal movement

Question 22

How to assess accessory nerve (CN 11)

Answer 22

Turn head
Raise shoulders (shrug)

Question 23

How to assess hypoglossal nerve (cn 12)

Answer 23

Stick out tongue (tremor or fasciculations)
Use tongue depressor to test ability to resist movement of tongue
Test tongues range of motion (side to side, retract on roof of mouth)

Question 24

Potential signs of damage in olfactory nerve (CN 1)

Answer 24

Ansomia- inability to smell

Question 25

Potential signs of damage in optic nerve (CN 2)

Answer 25

Blindness

Question 26

Potential signs of damage in oculomotor nerve (CN3 )

Answer 26

Ptosis Diplopia

Question 27

Potential signs of damage in trochlear (CN 4)

Answer 27

Diplopia Weakness of downward eye movement Affected eye drifts upwards

Question 28

Potential signs of damage in trigeminal (CN 5)

Answer 28

Facial anesthesia Loss of temperature and pain sensation Loss of sensation of superficial and deep structures Loss of sensation in anterior 2/3 of tongue Any weaknesses, asymmetry, tremor, fasciculations in jaw Weak jaw closure and lateralization Loss or weaak mastication

Question 29

Potential signs of damage in abducent nerve (CN 6)

Answer 29

medial eye deviation

Question 30

Potential signs of damage in facial nerve (CN 7)

Answer 30

paralysis of facial nerve muscles Poor labial retraction and pursing Poor lip seal Upper motor neuron damage > contralateral lower face Lower motor neuron damage > ipsilateral upper and lower face, eye closure Diminished jaw opening Loss of taste anterior 2/3 of tongue

Question 31

Potential signs of damage in vestibulocochlear nerve (CN 8)

Answer 31

Vertigo Disequalibrium Hearing loss

Question 32

Potential signs of damage in glossopharyngeal nerve (CN 9)

Answer 32

Weak cough reflex Loss of taste and sensation on posterior 1/3 May reduce gag reflex due to sensation (hyposensitivity or hypersensivitity)

Question 33

Potential signs of damage in vagus nerve (CN 10)

Answer 33

Loss of gag reflex (uvula will deviate to non-damaged side) Loss of cough reflex Hypernasality Dysphonia (hoarse, breathy, wet, etc.) Inability to vary pitch Difficulty swallowing (dysphagia) Impaired laryngeal closure Impaired VF adduction

Question 34

Potential signs of damage to accessory nerve (CN 11)

Answer 34

Head turning weakness Shoulder shrugging weakness

Question 35

Potential signs of damage to hypoglossal nerve (CN 12)

Answer 35

Atrophy of tongue muscles Fasciculations Deviation of tongue to weak side

Question 36

Innervation of the 12 pairs of cranial nerves

Answer 36

1. Olfactory- sensory 2. Optic- sensory 3. Oculomotor- motor 4. Trochlear- motor 5. Trigeminal- both 6. Abducent- motor 7. Facial- both 8. Vestibulocochlear- sensory 9. Glossopharyngeal- both 10, Vagus- both 11. Accessory- motor 12, Hypoglossal- motor