Cranial Nerves

Question 1

CNs of myelencephalon

Answer 1

VI-X, XII

Question 2

CN VI location

Answer 2

emerges from trapezoid body just lateral to pyraminds

Question 3

CN VII location

Answer 3

emerges from trapezoid body just medial to CN VIII

Question 4

CN VIII location

Answer 4

enters brainstem at lateral aspect of trapezoid body adjacent to cerebellum. The bulk of the nerve remains in PTB when brain is removed, only a stub remains attached to the brain. Sometimes difficult to differentiate from tissue cerebellum

Question 5

CN IX location

Answer 5

Multiple rootlets emerge from lateral aspect of medulla adjacent to cerebellum just cd to trap body; may be hard to find

Question 6

CN XII location

Answer 6

multiple rootlets emerge from cd medulla just lat to pyramids

Question 7

CN V location

Answer 7

enters/ emerges from the pons at lat aspect of transverse fibers of pons

Question 8

CN III location

Answer 8

emerges from ventral mesencephalon in middle of crus cerebri

Question 9

CN IV location

Answer 9

only CN to emerge from D aspect of brainstem; runs through rostral medullary vellum just cd to cd colliculi; may see it running down lat aspect of mesencephalon on your brains

Question 10

CN mesencephalon

Answer 10

CN III, CN IV

Question 11

CN Metencephalon

Answer 11

CN V

Question 12

CN I

Answer 12

olfactory; olfaction

Question 13

CN I signs of dysfunction

Answer 13

owners of hunting dogs may notice deficits otherwise limited; noxious substances assess CN V not olfaction

Question 14

CN II

Answer 14

optic; vision, PLR, visuomotor responses, circadian rhythm entrainment

Question 15

CN II tests

Answer 15

menace, PLR, visual following, obstacle navigation, visual placing

Question 16

CN III fx pt 1

Answer 16

oculomotor; motor to dorsal rectus, ventral rectus, medial rectus, ventral oblique, levator palpebrea

Question 17

CN III fx pt 2

Answer 17

motor to pupillary constrictor and cilliary muscles

Question 18

CN III test pt 1

Answer 18

ventrolateral strabismus of ipsilateral eye; VOR: no/ slow adduction of globe

Question 19

CN III test pt 2

Answer 19

No/ slow PLR anisocoria

Question 20

CN IV

Answer 20

trochlear; motor to dorsal oblique

Question 21

CN IV test

Answer 21

extortion or rotation of globe (calf vs cat)

Question 22

CN V

Answer 22

trigeminal V1 ophthalmic, V2 maxillary, V3 mandibular

Question 23

V1

Answer 23

ophthalmic; sensation to forehead, medial eyelid, eyeball, nasal mucosa (septum)

Question 24

V1 test

Answer 24

palpebral reflex (medial canthus), nasal septum sensation, corneal reflex (autonomous)

Question 25

V2

Answer 25

Maxillary; sensation to maxilla, upper lips, teeth, gums; lateral eyelid and nose, nasal mucosa, palate

Question 26

V2 test

Answer 26

palpebral reflex (lateral cants), sensation to nasal mucosa, punch upper lip lateral to canine (autonomous)

Question 27

V3 sensory

Answer 27

Mandibular; sensation to chin, tongue, and lower jaw, lip, teeth, and gums. Proprioception to teeth, masticatory muscles

Question 28

V3 sensory

Answer 28

pinch lower lip lateral to canine (autonomous)

Question 29

V3 motor

Answer 29

mandibular; motor to muscles of mastication (temporals, master, rostral digastrics, pterygoids)

Question 30

V3 motor test

Answer 30

muscle atrophy, decreased jaw tone and dropped jaw require bilateral loss of fx

Question 31

CN VI

Answer 31

abducent; motor to lateral rectus and retractor bulbi

Question 32

CN VI test

Answer 32

medial strabismus; VOR: no/ slow abduction; observe globe retraction with corneal stimulation or menace

Question 33

CN VII

Answer 33

facial nerve

Question 34

CN VII SE

Answer 34

motor to muscles of facial expression and caudal digastricus

Question 35

CN VII SE test

Answer 35

palpebral reflex, menace response, lip droop (lead to drooling, food falling from mouth), ear droop, facial asymmetry; Farm animals only: Ptosis

Question 36

CN VII VE

Answer 36

motor to all lacrimal mucous and salivary glands of head except parotid, zygomatic, and bucal

Question 37

CN VII VE test

Answer 37

schemer tear test

Question 38

CN VII SA

Answer 38

sensation to skin concave surface of pinna

Question 39

CN VII SA test

Answer 39

ear movement when concave surface of pinna is tickled

Question 40

CN VII SS

Answer 40

taste from rostral 2/3 tongue; no test

Question 41

CN VIII

Answer 41

vestibulocochlear; audition; vestibular fx

Question 42

CN VIII test

Answer 42

auditory orienting, clients report hearing loss, circling, nystagmus, positional strabismus, head tilt

Question 43

CN IX

Answer 43

glossopharyngeal

Question 44

CN IX SE

Answer 44

motor to muscles of soft palate and pharynx

Question 45

CN IX SE test

Answer 45

gag reflex, dysphagia

Question 46

CN IX VA

Answer 46

carotid body and carotid sinus, sensory from caudal tongue and pharyngeal mucosa

Question 47

CN IX VA test

Answer 47

gag reflex

Question 48

CN IX SS

Answer 48

Taste cd 1/3 tongue; no test

Question 49

CN IX VE

Answer 49

parotid, zygomatic, and buccal salivary glands; no test

Question 50

CN X

Answer 50

vagus

Question 51

CN X SE

Answer 51

motor to muscles of pharynx larynx and esophagus

Question 52

CN X SE test

Answer 52

gag reflex, dysphagia, voice change, inspiratory stridor, aspiration

Question 53

CN X VA

Answer 53

Visceral sensation from pharynx, larynx, trachea, thoracic, and abdominal viscera

Question 54

CN X VA test

Answer 54

gag reflex

Question 55

CN X VE

Answer 55

visceral motor to thoracic and abdominal viscera (terminal ganglia); no clinically practical way to asses this

Question 56

CN XI

Answer 56

accessory; motor to sternocephalicus, cleidocephalicus, omotransversarius

Question 57

CN XI test

Answer 57

neck movement, trapezius atrophy

Question 58

CN XII

Answer 58

Hypoglossal; motor to intrinsic and extrinsic muscles of tongue. Involved in swallowing, licking, and chewing

Question 59

CN XII test

Answer 59

Tongue deviates towards side of lesion, trouble drinking, tongue atrophy