Midterm - Cranial Nerve more

Question 1

CN I

Answer 1

Olfactory nerve

Sensory: ability to smell

Question 2

CN I test

Answer 2

Odor recognition

Question 3

Amosmia vs hyposmia

Answer 3

Anosmia = complete loss of sense of smell
Hyposmia = diminished sense of smell

Question 4

Loss of smell is commonly (bilateral/unilateral) and due to _____

Answer 4

Bilateral

Chronic rhinitis, fracture to cribiform plate, etc

Question 5

Anosmia that is a new onset and unilateral is

Answer 5

Most concerning. Suggests possible intracranial mass

Question 6

Dysosmia/parosmia

Answer 6

Difficulty identifying odors. A CN I problem

*considered idiopathic

Question 7

Phantosmia

Answer 7

Hallucination of an odor when none present. A CN I problem

*implies a problem in the olfactory cortex

Question 8

CN II

Answer 8

Optic nerve

Sensory only: vision & afferent portion of pupil constriction

Question 9

CN II tests

Answer 9

1. Visual acuity
2. Peripheral vision
3. Pupillary light reflexes (affarent portion)
4. Visualize optic disc

Question 10

Primary open angle glaucoma can cause

Answer 10

Globally narrowed visual fields (high pressure in the eye damages the optic nerve)

Question 11

What is Normal response to light?

And what is direct and consensual response?

Answer 11

Miosis = pupil constriction

Direct response = pupil with the light source constricts

Consensual = constriction fo the pupil in the eye opposite from the light source

Question 12

How does light coming in one eye constrict both pupils?

Answer 12

Light come in one eye, travel along CN II which synapses with CN III. CN III generates efferent motor response bilaterally, causing pupil constriction

Question 13

CN III

Answer 13

Oculomotor nerve. Efferent motor.

Innervates the levator palpebrea superioris muscle which causes eyelid elevation

Controls 4/6 muscles involved in moving the eye: inferior oblique, inferior superior and medial rectus

Question 14

CN III tests

Answer 14

1. Pupillary light reflex - motor component of pupil constriction
2. Check for intact eyelid elevation
3. Assess cardinal fields of gaze (evaluates CN III, IV, VI)
   - also corneal light reflection & cover/ uncover tests for strabismus
4. Accommodation

Question 15

Abnormal CN III function

Answer 15

Droopy eyelid (ptosis)

Question 16

Dysconjugate gaze

Answer 16

Eyes that don’t move in parallel

Usually indicates paresis (weakness) or paralysis of extra-ocular muscles

Question 17

End point nystagmus is ______ whereas involuntary nystagmus through the cardinal fields of gaze is ______

Answer 17

Normal, abnormal

Question 18

Lateral rectus m is innervated by ____ and does _____

Answer 18

CN VI, eye abduction

Question 19

Superior oblique is innervated by ____ and does ____

Answer 19

CN IV, moves eyes down and in

Question 20

Signs of complete right CN III palsy

Answer 20

Dilated pupil (mydriasis), ptosis, can’t move the R eye medically

Question 21

A patient with disconjugate gaze will complain of ________ and tends to occur in the direction (of/ opposite) the dysconjugate gaze

Answer 21

Double vision (diplopia), in direction of dysconjugate gaze

Question 22

Asymmetric corneal reflections indicates _____

Answer 22

Strabismus = deviation of normal ocular alignment

aka heterotropia

Question 23

The cover/ uncover test assesses for ____

Answer 23

Phoria (latent strabismus)

• patient looks straight ahead with both eyes, cover one eye, the covered eye will deviate when not in use, the eye moves back to center when you uncover it

Question 24

In Accommodation (aka convergence), the eyes should both move inward together until about ___ inches from the bridge of the most and pupils should _____

Answer 24

5 inches, constrict

Question 25

What is the accommodation triad? Aka near reflex

Answer 25

1. The eyes should converge (CN III) 2. The pupils should constrict (CN III) 3. Lenses should change shape (not visible to examiner - parasympathetic innervation)

Question 26

Cranial nerve palsies are often cause by intracranial problems such as

Answer 26

- cerebral vascular accidents - tumors - trauma - multiple sclerosis - infection - migraines Can be congenital

Question 27

CN V

Answer 27

Trigeminal nerve Sensory and motor innervation Muscles of mastication

Question 28

CN V tests

Answer 28

- bite the stick - light touch and pain sensation - corneal reflex (blink reflex)

Question 29

Where do V1, V2 and V3 have sensory innervation?

Answer 29

V1 (ophthalmic) - forehead and top of nose) V2 (maxillary) - bottom of nose, upper lip, zygomatic process V3 (mandibular) - anterior to ear, lateral mandible and chin/bottom lip

Question 30

What is Trigeminal neuralgia/neuropathy aka Tic Doulourex? peak onset? Pain characteristics? Trigger zones Causes Management

Answer 30

Facial pain in the trigeminal distribution between maxi alley and mandibular branch 60-70 - sharp, lancinating, - lips, gums, cheek or chin - unilateral - paroxysmal - seconds to minutes Trigger zones - small areas in the region of the nose and mouth (possibly brushing teeth, chewing, cold exposure) - idiopathic, sometimes from contact/compression by other structures (superior cerebellar artery, multiple sclerosis plaques, tumor) - MRI, referral to neurologist, medication (anti-seizure)

Question 31

Corneal reflex (blink reflex) tests the ___ part of CN V and CN ____ controls eyelid closure. What is Normal/abnormal response

Answer 31

CN V1 (ophthalmic branch) CN VII controls orbicularis oculi muscles for lid closure Normal: light touch to cornea (CN V) causes both eyes to blink (CN VII) Abnormal: absent blink in either or both eyes

Question 32

CN VII

Answer 32

Facial nerve Motor and sensory functions Facial expression, taste, corneal reflex

Question 33

CN VII facial expression abnormalities can be due to peripheral nerve lesion (LMN) such as _____ and central lesion (UMN) such as ____

Answer 33

Bell’s palsy | Stroke or tumor

Question 34

Forehead/eyebrows have (unilateral/bilateral) UMN and (unilateral/bilateral) LMN innervation An injury to CN VII LMN will cause loss function of the (upper/lower/both) divisions of the face? This is known as ______

Answer 34

Bilateral UMN, unilateral LMN Both = bell’s palsy

Question 35

- sudden onset, one-sided facial paresis/paralysis but no loss of facial sensation (exception: taste) - unable to raise eyebrow/wrinkle the forehead - can’t fully close the eye - loss of Nash-labial folds - drooping of the corner of the mouth - trouble with lip sounds B,P and M

Answer 35

CN VII Bell Palsy

Question 36

What are risk factors for Bell Palsy? What are the causes?

Answer 36

Diabetes, pregnancy, history of Herpes Simplex Virus (HSV) or Varicella Zoster Virus (VZV) Idiopathic, possibly virally-mediated

Question 37

What is the management and prognosis of bell palsy?

Answer 37

- eye drops/temporary patch - refer to PCP for co-management Urgent but not an emergency, corticosteroids +/- antivirals Most often resolves over 3-6 weeks

Question 38

UMN lesion of CN VII (will/ will not) spare the forehead?

Answer 38

Will spare the forehead but the contralateral lower face will have deficits

Question 39

What part of the tongue does CN VII innervate?

Answer 39

Sensory (taste) to the anterior 2/3 of the tongue

Question 40

CN VIII

Answer 40

Auditory nerve 2 divisions (vestibular and cochlear) Both sensory

Question 41

How do you test the cochlear division of CN VIII?

Answer 41

Whisper test *if the patient fails, perform the Weber and Rinne tests to asses for conductive vs sensorineural hearing loss

Question 42

What is conductive hearing loss?

Answer 42

External sound waves from the air are not able to gain access to the inner ear Due to trauma, infection, inflammation, foreign body, cerumen buildup, etc. in the outer or middle ear

Question 43

What is sensorineural hearing loss?

Answer 43

Caused by damage to the inner ear or the cochlear branch of CN VIII Ex: aging and acoustic neuroma

Question 44

In Webber’s test, sound will lateralize to the _____ side in conductive hearing loss or the ______ side in sensorineural hearing loss

Answer 44

Affected, unaffected

Question 45

Abnormal rinne test results for conductive and sensorineural hearing loss

Answer 45

Conductive: Bone conduction (BC) > air conduction (AC) Sensorineural: AC>BC in affected ear but diminished compared to normal

Question 46

CN IX and CN X

Answer 46

Glossopharyngeal & Vagus | Both have motor and sensory functions

Question 47

CN IX and CN X tests

Answer 47

“Say ahhh” Gag reflex Observe patients ability to speak clearly Check the oropharynx: uvula midline, upward movement of soft palate is symmetrical, gag reflex intact and symmetrical

Question 48

What part of the tongue does CN IX innervate?

Answer 48

Sensory to the posterior 1/3 of the tongue

Question 49

CN XI

Answer 49

Spinal accessory nerve | Motor: trapezius and SCM muscles

Question 50

CN XII

Answer 50

Hypoglossal nerve | Motor: tongue movement

Question 51

CN XII tests

Answer 51

- stick out your tongue and move side to side | - say L, D, T and N

Question 52

When there is an issue with one side of the hyppoglossal nerve, the tongue will deviate (toward/away from) the side of lesion

Answer 52

Toward *the functioning side will dominate