Cranial Nerves Flashcards
How many pairs of cranial nerves are there?
12 pairs
What are the 12 cranial
Olfactory
Optic
Oculomotor
Trochlear
Trigeminal
Abducent
Facial
Vestibulocochlear
Glossopharyngeal
Vagus
Accessory
Hypoglossal
Primary function of the olfactory CN
smell
Primary function of the optic CN
vision
Primary function of the oculomotor CN
eyelid opening, eyeball motion up and down
Primary function of the Trochlear CN
Eye motion up and down
Branches of the trigeminal nerve
-ophthalmic
-Maxillary
-Mandibular
Primary function of the trigeminal CN
-TMJ/jaw movements and senssation
-Forehead movements; facial movements
-Cheeks
Primary function of the abducent CN
Eye movements outward (abduction)
Primary function of the facial CN
Facial expression (kissy face, puffer face, pout face)
Hyoid elevation
Salivary glands
Mandibular depression
Primary function of vestibulocochlear CN
Balance & hearing
Primary function of the glossopharyngeal CN
Pharyngeal constrictors
Pharyngeal muscles moving it up and down
Taste/sensation posterior 1/3 of tongue
Primary function of the vagus CN
Taste receptor in posterior oral cavity
Laryngeal muscles
Primary function of the accessory CN
Neck and shoulder movements
Primary function of the hypoglossal CN
tongue movements
How to assess the oculomotor nerve (CN 3)
Look for eyelid drooping
Pt moves eyes up, down, inward
How to assess trochlear nerve (CN 4)
Pt looks towards nose
Pt looks up and down
How to assess trigeminal nerve (CN 5)
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
how to assess facial nerve (CN 7)
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
How to assess glossopharyngeal nerve (CN 9)
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
How to assess vagus nerve (CN 10)
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
How to assess accessory nerve (CN 11)
Turn head
Raise shoulders (shrug)
How to assess hypoglossal nerve (cn 12)
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)
Potential signs of damage in olfactory nerve (CN 1)
Ansomia- inability to smell
Potential signs of damage in optic nerve (CN 2)
Blindness
Potential signs of damage in oculomotor nerve (CN3 )
Ptosis
Diplopia
Potential signs of damage in trochlear (CN 4)
Diplopia
Weakness of downward eye movement
Affected eye drifts upwards
Potential signs of damage in trigeminal (CN 5)
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
Potential signs of damage in abducent nerve (CN 6)
medial eye deviation
Potential signs of damage in facial nerve (CN 7)
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
Potential signs of damage in vestibulocochlear nerve (CN 8)
Vertigo
Disequalibrium
Hearing loss
Potential signs of damage in glossopharyngeal nerve (CN 9)
Weak cough reflex
Loss of taste and sensation on posterior 1/3
May reduce gag reflex due to sensation (hyposensitivity or hypersensivitity)
Potential signs of damage in vagus nerve (CN 10)
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
Potential signs of damage to accessory nerve (CN 11)
Head turning weakness
Shoulder shrugging weakness
Potential signs of damage to hypoglossal nerve (CN 12)
Atrophy of tongue muscles
Fasciculations
Deviation of tongue to weak side
Innervation of the 12 pairs of cranial nerves
- Olfactory- sensory
- Optic- sensory
- Oculomotor- motor
- Trochlear- motor
- Trigeminal- both
- Abducent- motor
- Facial- both
- Vestibulocochlear- sensory
- Glossopharyngeal- both
10, Vagus- both - Accessory- motor
12, Hypoglossal- motor
