Lecture 9: Cranial Nerves

Question 1

cranial nerves consist of:

1. ___ ___ fibers that originate in the nuclei of the brainstem (LMNs)
2. ___ ___ fibers that originate in the peripheral ganglia (trigeminal ganglia)

Answer 1

efferent motor; afferent sensory

Question 2

the corticobulbar pathway ___ at the level of the CN nuclei

Answer 2

crosses over / decussates

Question 3

CN V

Answer 3

trigeminal nerve

Question 4

when a nerve is a mixed nerve, it has both ___ and ___ functions

Answer 4

motor; sensory

Question 5

the trigeminal nerve is a mixed nerve; its motor and sensory roots attach at the ___

Answer 5

pons

Question 6

the trigeminal nerve’s sensory pathway terminates in the ___

Answer 6

trigeminal sensory nucleus (outside and away from its cell body in trigeminal ganglia)

Question 7

muscles closing jaw : masseter, temporalis, medial pterygoid :: muscles opening jaw : 1. ___ 2. ___ 3. ___

Answer 7

1. lateral pterygoid
2. anterior belly of diagastric
3. mylohyoid

re: trigeminal nerve motor innervation

Question 8

the tensor veli palatini tenses the velum, whereas the tensor tympani tenses the ___

Answer 8

tympanic membrane

re: trigeminal nerve motor innervation

Question 9

name of the nerve providing sensation for the forehead, eyes, and nose

Answer 9

opthamalic nerve

re: trigeminal nerve sensory innervation

Question 10

name of the nerve providing sensation for the upper lip mucosa, maxilla, upper teeth, cheeks, palate, and maxillary sinus

Answer 10

maxillary nerve

re: trigeminal nerve sensory innervation

Question 11

name of the nerve providing sensation for the anterior 67% of tongue, mandible, lower teeth, lower lip, part of the cheek, and part of the external ear

Answer 11

mandibular nerve

re: trigeminal nerve sensory innervation

Question 12

name of the nerve that supports the following functions:

mastication, articulation, hyolaryngeal elevation, tensing / closure of the soft palate, sensation to the face, teeth, gums, and anterior 67% of the tongue

Answer 12

trigeminal nerve / CN V

Question 13

re: trigeminal nerve / CN V

unilateral UMN damage : no significant motor deficits :: unilateral LMN damage : 1. ___ 2. ___ 3. ___

Answer 13

1. mandible deviates toward side of paralysis / paresis during opening
2. muscle hypotonia and atrophy
3. impaired hyolaryngeal elevation

Question 14

re: trigeminal nerve / CN V

[choose] ___ (UMN / LMN) damage:
hypertonia, slow movements, restricted jaw opening / closing, reduced hyolaryngeal elevation

Answer 14

bilateral UMN

Question 15

re: trigeminal nerve / CN V

[choose] ___ (UMN / LMN) damage:
hypotonia, significantly impaired jaw opening / closing, significantly impaired hyolaryngeal elevation

Answer 15

bilateral LMN

Question 16

in trigeminal nerve ___ testing, the clinician lightly strokes above the eyebrows, the upper lip and central cheek, and between the lower lip and the chin

which three branches are stimulated?

Answer 16

sensory;

opthalamic, maxillary, and mandibular, respectively

Question 17

CN VII

Answer 17

facial nerve

Question 18

the facial nerve is a ___ nerve; its motor and sensory roots attach at the pons

Answer 18

mixed

Question 19

the facial nerve’s sensory pathway terminates in the ___ for taste and the ___ for touch

Answer 19

nucleus of the tracts solitaries; spinal nucleus of the trigeminal nerve

Question 20

in the facial canal, the greater superficial petrosal, lesser petrosal, and external petrosal meet at the ___

Answer 20

geniculate ganglion

Question 21

CN VII monitors muscles of ___; it also innervates the latysma, stylohyoid, stapedius, posterior belly of the digastric, and glands (3)

Answer 21

facial expression

re: facial nerve motor innervation

Question 22

name of the nerve sensory to taste (floor of mouth, hard and soft palates) and touch (external ear, auditory meatus)

Answer 22

facial nerve / CN VII

re: facial nerve sensory innervation

Question 23

name of the nerve that supports the following functions:

movements of facial expressions, hyolaryngeal elevation, saliva and tear production, and taste at the front of the tongue

Answer 23

facial nerve / CN VII

Question 24

___ testing of the ___ nerve includes: looking at facial symmetry, forehead wrinkle, tight eye closure, smile, and maintained resistance of lips and puffed cheeks

Answer 24

motor; facial

Question 25

re: facial nerve / CN VII [choose] (unilateral / bilateral) UMN damage : spastic paralysis of the whole face :: (unilateral / bilateral) UMN damage : contralateral lower face weakness

Answer 25

bilateral; unilateral

Question 26

___ testing of the ___ nerve includes: testing taste (salty, sour, bitter, sweet) on each side of the tongue

Answer 26

sensory; facial

Question 27

CN IX

Answer 27

glossopharyngeal nerve

Question 28

the glossopharyngeal nerve is a mixed nerve; it emerges from the ___, with motor portions originating in the nucleus ambiguus and sensory components in the nucleus solitarius

Answer 28

medulla

Question 29

name of the nerve that supports the following functions: elevation of larynx and pharynx during swallowing, sensory innervation of the tongue and soft palate - including gag reflex

Answer 29

glossopharyngeal nerve / CN IX

Question 30

motor and sensory testing of the glossopharyngeal nerve includes testing for ___

Answer 30

gag reflex

Question 31

CN X

Answer 31

vagus nerve

Question 32

CN XI

Answer 32

spinal accessory nerve

Question 33

CN XII

Answer 33

hypoglossal nerve

Question 34

the hypoglossal nerve is a ___-only nerve; it originates from the hypoglossal nucleus in the ___

Answer 34

motor; medulla

Question 35

the hypoglossal nerve innervates intrinsic muscles of the tongue and innervates these three extrinsic muscles of the tongue: 1. ___ 2. ___ 3. ___

Answer 35

1. genioglossus 2. hyoglossus 3. styloglossus re: hypoglossal nerve motor innervation

Question 36

name of the nerve that supports the following functions: innervates muscles of the tongue involved in articulation, innervates oral stage swallowing muscles, innervates one pharyngeal stage swallowing muscle

Answer 36

hypoglossal nerve / CN XII

Question 37

name of the nerve that conducts these motor testing protocols: observing tongue at rest, protrude tongue, push tongue against inside of cheek, rapid alteration of tongue movements

Answer 37

hypoglossal nerve / CN XII

Question 38

in hypoglossal nerve motor testing, if the patient pushes their tongue weakly against the left cheek then the weakness is on the ___ side

Answer 38

right, the side that pushes

Question 39

in hypoglossal nerve motor testing, if the patient pushes their tongue weakly against the right cheek then the weakness is on the ___ side

Answer 39

left, the side that pushes

Question 40

re: hypoglossal nerve / CN XII unilateral UMN damage : ___ tongue weakness :: unilateral LMN damage: ___ tongue weakness

Answer 40

contralateral; ipsilateral

Question 41

most of the extrinsic muscles of the tongue : bilaterally innervated :: ___ : contralaterally innervated re: hypoglossal nerve / CN XII

Answer 41

genioglossus - the only one that receives contralateral innervation

Question 42

bilateral UMN and bilateral LMN damage will result in weakness on ___ sides re: hypoglossal nerve / CN XIi

Answer 42

both

Question 43

name of the type of damage most often presenting with reduced range of motion and slow movements in patients with hypoglossus nerve (CN XII) damage

Answer 43

bilateral UMN

Question 44

basic facts of CN XI, the spinal accessory nerve

Answer 44

motor only, consists of cranial roots (innervate palatal muscles) and spinal root (innervate the sternocleidomastoid and trapezius muscles)

Question 45

name of the nerve whose function is to help turn, tilt, and thrust head forward

Answer 45

spinal accessory nerve / CN XI

Question 46

name of the most complex cranial nerve

Answer 46

vagus nerve / CN X

Question 47

basic facts of CN X, the vagus nerve

Answer 47

contains laryngeal and pharyngeal branches; main functions include voice production and swallowing; sensory innervation responsible for cough reflex and detection of residue after swallow; motor testing includes gag reflex paired with production of "ah"

Question 48

true or false: most cranial nerves receive bilateral LMN innervation

Answer 48

false; most CNs receive bilateral UMN innervation