Cranial nerves

Question 1

what does it mean to be a branchiomeric

Answer 1

it comes from branchial arches nd innervates corresponding muscles of branchial arches, they are V VII, IX, X XI

Question 2

what cn’s are Branchiomeric

Answer 2

V VII, IX, X XI

Question 3

describe Goldberg image of CN locations

Answer 3

I and II are above midbrain
III and IV in midbrain

V, VI, VII, VIII level of pons with some spread

IX, X, XI, XII medulla

Question 4

what are the two sensory cn’s?

Answer 4

I and II

Question 5

CN III controls what

Answer 5

medial rectus for adduction of the eye

Question 6

primary function of Iv

Answer 6

intorsion/rotation around the visual axis, not changing the position of the pupil

Question 7

LR ___ SO ___ all the rest are ____

Answer 7

6, 4, 3

Question 8

how many branches does cn V have

Answer 8

3 (ophthalmic, maxillary, mandibular)

Question 9

what does tensor tympani do

Answer 9

attached to the malleus near the tympanic membrane
Contraction stiffens the ossicluar chain to reduce transmission of sounds mainly in the low frequencies

Question 10

abducts the eye

Answer 10

lateral rectus muscle (cn 6)

Question 11

motor cn’s

Answer 11

III, IV, VI, XI, XII

Question 12

mixed cn’s

Answer 12

V, VII, VIII due to efferent and afferent components, IX, X

Question 13

cn 1

Answer 13

olfactory - smell

Question 14

CN 2

Answer 14

optic - Vision

Question 15

CN 3

Answer 15

Occulomotor - m: pupillary constrictor muscle
Innervates: superior rectus, inferior oblique, inferior rectus, medial rectus

Question 16

controls medial rectus for adduction of the eye

Answer 16

CN III

Question 17

CN IV

Answer 17

Trochlear - superior oblique muscle causes intorsion (also downward and out

Question 18

cn v

Answer 18

trigeminal - Motor (muscles of mastication, tensor tympani)
Sensory (touch, pressure, pain, and temperature from facial dermatomes)

Question 19

CN VI

Answer 19

Abducens - lateral rectus muscle which abducts the eye

Question 20

CN VII

Answer 20

Facial - M: facial expression, stapedius muscle)
S: taste anterior 2/3 of tongue and touch, pressure pain temp sensations soft palate and tonsils

Question 21

Axons of CN VII exit where

Answer 21

pontomedullary junction just medial to CN VIII
Travels in the internal auditory canal
3 branches: chorda tympani (is in middle ear), greater petrosal nerve, facial nerve

Question 22

what can be altered during middle ear surgery and what happens?

Answer 22

taste changes, chorda tympani

Question 23

when does stapedius muscle pull

Answer 23

reduces transmission below 1-2 kHz)

Question 24

What One branch of the facial nerve travels to back of head.

Answer 24

PAM - Post Auricular Muscle

Question 25

what is bell’s palsy

Answer 25

facial nerve paralysis (CN VII

Question 26

What symptoms show in bell’s palsy? can they recover?

Answer 26

Loss of blink, eyelid does not close, corneal drying, asymmetric smile
Approx 80% recovery w/in 3 months

Question 27

does the stapedius muscle work in bell’s pasly?

Answer 27

no, they have a low tolerance of loud sounds

Question 28

what is the House-Brackmann Facial Paralysis Scale grading?

Answer 28

gets mildly worse as the numbers go up from 1

Question 29

why do we use nonacoustic middle ear reflex?

Answer 29

By using non-acoustic middle ear reflex we can determine if afferent or efferent is at fault.

Question 30

if we have present nonacoustic MEMR from touch…

Answer 30

CN VII & Stapedius is working
afferent CN VIII is the issue

Question 31

if we have absent non acoustic MEMR from touch

Answer 31

CN VII & Stapedius is not working

Question 32

if absent non acoustic MEMR with touch but is present from air puff…

Answer 32

CN VII/Stapedius is not working
CN V and tensor are working

Question 33

do we have a distribution of taste budes?

Answer 33

yes, it is mapped some

Question 34

CN VIII

Answer 34

vestibulocochlear
special sensory

Question 35

CN IX

Answer 35

Glossopharyngeal - M: (pharyngeal and palatine muscles) and parasympathetic (innervates parotid gland) functions
S: touch, pain and gag reflex from palate, tonsillar and pharyngeal regions; taste from posterior 1/3 of tongue; and chemoreception of arterial blood

Question 36

CN X

Answer 36

Vagus
branchiomeric
Innervates heart, bronchial smooth muscle, intestinal smooth muscle, larynx and pharynx and aids in digestive secretions
Sensory info gathered from larynx, trachea, lungs, heart and blood vessels

Question 37

cn xi

Answer 37

accessory
branchiomeric
Accessory nucleus is in the dorsolateral portion of the spinal cord
Separates from vagus nerve and innervates ipsilateral sternocleidomastoid and trapezius muscles (neck and shoulders)
Cranial root also innervates vocal cords

Question 38

how do we test for damage to CN XI

Answer 38

ask them to shrug their shoulders, one will only go up show
turn their head against resistance
once nerve exits the skull it won’t cross over again, the r nerve goes to right muscles etc.

if nucleus is damaged in the bs it will be opposite the nucleus and not on the same side because it hasn’t crossed over yet.

Question 39

cn xii

Answer 39

hypoglossal
tongue

Question 40

what happens to damage of CN XII

Answer 40

if tongue is stuck out they both need to be used equally
if told to stick it straight out and if one side goes out and deviates toward the other the lesion is on that side of the deviation
if damage is coming from cortex before crossing over, this is where we would see the tongue deviation on the opposite side of the lesion