Cranial Nerve Screens Flashcards
What is cranial nerve I?
Olfactory
How do you test the Olfactory nerve?
Have them smell something and tell you what it is. For example, an alcohol pad.
Is Cranial Nerve I sensory or motor?
Purely sensory. It’s function is smell.
What are possible abnormal findings in CN 1?
Anosmia: an inability to detect smells
Seen with frontal lobe lesions
Optic Nerve
Cranial Nerve II
Function: vision
Purely sensory
How do you test CN 2?
Test visual acuity. Central: Snellen eye chart; test each eye separately at a distance of 20 feet Peripheral vision (visual fields): by confrontation - have patient sum fingers you are holding up
What are possible abnormal findings for CN 2?
Blindness, myopia (nearsightedness), presbyopia (farsightedness)
Field defects: homonymous hemianopsia
Cranial Nerve 3
Oculomotor
Function: Pupillary reflexes
Purely motor
How do you test Oculomotor?
Use the H test.
Test pupillary reactions by shining light in eye
If abnormal, test near reaction.
Examine pupillary size/shape
What are possible abnormal findings for the oculomotor nerve?
Absence of pupillary constriction
Anisocoria (unequal pupils)
Horner’s syndrome, CN 3 paralysis
Trochlear Nerve
CN 4
Function: extraocular movements. Pupillary constriction and eye movements.
Purely motor
How do you test CN 4?
H test
What are possible abnormal findings for CN 4?
Strabismus (eye deviates from normal conjugate position)
Impaired eye movements
Double vision
Cranial Nerve 5
Trigeminal nerve
Function: sensory - face
sensory - cornea
motor - muscles of mastication
How do you test CN 5?
Palpate the temporal and masseter muscles while they clench
What are possible abnormal findings for the trigeminal nerve?
Loss of facial sensations or weakness and wasting of muscles
When opened, deviation of jaw to ipsilateral side
Abducens Nerve
Cranial Nerve 6
Function: Lateral rectus: turns eye out
Purely motor
How do you test CN 6?
H test (lateral tracking)
What are possible abnormal findings for the abducens?
Esotropia (eye pulled inward)
Eye cannot look out
Cranial Nerve 7
Facial nerve
Function: facial expression.
Taste to anterior two thirds of tongue
Mixed motor and sensory
How do you test the facial nerve?
Raise eyebrows, puff out cheeks, smile
What are possible abnormal findings in the facial nerve?
Paralysis:
inability to close eye, drooping corner of mouth, and difficulty with speech articulation
Vestibulocochlear nerve
Cranial nerve 8
Function: vestibular function and cochlear function. Equilibrium.
Purely sensory
How do you test CN 8?
Rub fingers next to both ears or whisper
Weber’s test = vibration on the forehead
What are possible abnormal findings for CN 8?
Vertigo, dysequilibrium, nystagmus
Deafness, tinnitus
Conductive loss
Cranial Nerve 9
Glossopharyngeal
Function: Sensory to posterior one third of tongue, pharynx, middle ear
Mixed motor and sensory
How do you test CN 9?
Gag reflex
Not usually tested
Vagus nerve
Cranial nerve 10
Function: vocal sounds, swallowing, pharynx control
Mixed motor and sensory
How do you test the vagus nerve?
Have the patient say “ah” and check for uvula deviation
What are possible abnormal finding for CN 10?
Paralysis: palate fails to elevate
Asymmetrical elevation
Cranial Nerve 11
Spinal accessory nerve
Function: motor - trapezius muscle, sternocleidomastoid
Purely motor
How do you test CN 11?
Test the same way as C4 myotome
What are possible abnormal finding for CN 11?
LMN: atrophy, ipsilateral weakness, inability to shrug ipsilateral shoulder
UMN: weakness of ipsilateral sternocleidomastoid and contralateral trapezius
Hypoglossal nerve
Cranial Nerve 12
Function: Tongue movements
Purely motor
How do you test CN 12?
Patient pushes tongue into cheek and then examiner resists OR pt protrudes tongue and watch for deviation
What are possible abnormal findings for CN 12?
Dysarthria, impaired movements, deviation to weak side
