Chapter 20 Cranial Nerves

Question 1

CN I

Answer 1

Olfactory

Question 2

CN II

Answer 2

Optic

Question 3

CN III

Answer 3

Oculomotor

Question 4

CN IV

Answer 4

Trochlear

Question 5

CN V

Answer 5

Trigeminal

Question 6

CN VI

Answer 6

Abducens

Question 7

CN VII

Answer 7

Facial

Question 8

CN VIII

Answer 8

Vestibulocochlear

Question 9

CN IX

Answer 9

Glossopharyngeal

Question 10

CN X

Answer 10

Vagus

Question 11

CN XI

Answer 11

Accessory

Question 12

CN XII

Answer 12

Hypoglossal

Question 13

Cranial Nerves have 4 functions

Answer 13

1. supply motor innervation to muscles of the face, eyes, tongue, jaw, and 2 superficial neck muscles
2. transmit somatosensory information from the skin and muscles of the face and the temporomandibular joint
3. Transmit special sensory information related to visual, auditory, vestibular, taste, olfactory, and visceral senses
4. provide parasympathetic regulation of pupil size, curvature of eye lens, heart rate, blood pressure, breathing, and digestion

Question 14

Olfactory Nerve Lesions

Answer 14

result in inability to detect smells

Question 15

Trigeminal Nerve Lesions

Answer 15

results in anesthesia of the area supplied by the ophthalmic, maxillary, or mandibular branch

Question 16

Trigeminal neuralgia

Answer 16

dysfunction of the trigeminal nerve that produces severe, sharp, stabbing pain
pain triggered by eating, talking, touching

Question 17

facial nerve lesions

Answer 17

causes paralysis or paresis of the ipsilateral muscles of facial expression
lesion causes one side of the face to droop

Question 18

Bell’s palsy

Answer 18

if a lesion involves the facial nerve and the cause is unknown
diagnosis of exclusion

Question 19

Identifiable causes of facial nerve palsy include

Answer 19

trauma
lyme
MS
cyst in the middle ear
tumor
Ramsay Hunt Syndrome

Question 20

Ramsay Hunt Syndrome

Answer 20

facial and vestibulocochlear nerves are affected
caused by varicella-shingles
consists of acute facial paralysis, ear pain, and blisters on the external ear

Question 21

facial muscle synkinesis

Answer 21

abnormal reinnervation of facial muscles causes synkinesis-involuntary movements that accompany voluntary movements

Question 22

unilateral corticobrainstem lesion

Answer 22

interrupts voluntary control of contralateral facial muscles only on the lower half of the face

Question 23

conductive deafness

Answer 23

occurs when transmission of vibrations is prevented in the outer or middle ear
causes: wax in outer ear canal, otitis media

Question 24

sensorineural deafness

Answer 24

due to damage to receptor cells or the cochlear nerve
less common
causes: ototoxic drugs, Meniere’s disease, acoustic neuroma

Question 25

tinnitus

Answer 25

infrequent, mild, high-pitched sounds lasting for seconds to minutes

Question 26

glossopharyngeal lesion

Answer 26

interrupts the afferent limb of both the gag reflex and the swallowing reflex

Question 27

vagus nerve lesion

Answer 27

results in difficulty speaking and swallowing, poor digestion, asymmetric elevation of the palate, hoarseness, and loss of the gag and swallowing reflex

Question 28

accessory nerve lesion

Answer 28

causes flaccid paralysis of the ipsilateral sternocleidomastoid and trapezius muscles

Question 29

hypoglossal nerve

Answer 29

causes atrophy of the ipsilateral tongue

Question 30

dysphagia

Answer 30

difficulty swallowing

Question 31

dysarthria

Answer 31

poor control of speech muscles
motor production of sound is affected