Cranial Nerves

Question 1

CN IX name & function

Answer 1

Glossopharyngeal nerve
- taste from posterior 1/3 of tongue
- motor to stylopharyngeus muscle
- parasympathetic to parotid salivary glands
- visceral sensory from carotid sinus & body
- sensory to tympanic cavity, auditory tubes, upper pharynx, soft palate, posterior 1/3x of tongue

Question 2

Lesion of CN IX

Answer 2

• loss of sensation (or intense pain) of upper pharynx
• reduced/absent gag reflex
• difficulty adjusting BP/HR to postural changes

Question 3

CN IX nuclei

Answer 3

• solitary nucleus (taste, visceral afferents)
• nucleus ambiguus (motor & parasympathetic)
• inferior salivatory nucleus (parasympathetic)

Question 4

CN X function

Answer 4

Vagus nerve:
- parasympathetic to thoracic & abdominal viscera (lungs heart, GI)
- motor to pharyngeal constrictors, intrinsic laryngeal, palatal muscles for phonation & swallowing
- taste from larynx & epiglottis
- sensory to larynx, small portion of external ear, meninges in posterior cranial fossa and foramen magnum

Question 5

CN X name

Answer 5

Vagus nerve

Question 6

CN IX name

Answer 6

Glossopharyngeal nerve

Question 7

CN X nuclei

Answer 7

• Dorsal motor nucleus of vagus (parasympathetic)
• nucleus ambiguus (motor)
• solitary nucleus (taste, visceral afferents)

Question 8

CN X lesion

Answer 8

• loss of parasympathetics to thorax & abdomen (^HR, dec digestion)
• dysphonia (hoarse voice), dysphagia (difficulty swallowing)

Question 9

CN XI name

Answer 9

Accessory nerve

Question 10

CN XI function

Answer 10

Accessory
- cranial: motor to pharyngeal, laryngeal, palatal muscles (runs with CN X)
- spinal: motor to trapezius & sternocleidomastoid muscles

Question 11

CN XI lesion

Answer 11

Paralysis of ipsilateral trapezius & sternocleidomastoid muscles

Question 12

CN XI nuclei

Answer 12

Nucleus ambiguus (motor)
Disperse cell bodies in medulla & cervical spinal cord

Question 13

CN XII name

Answer 13

Hypoglossal nerve

Question 14

CN XII nuclei

Answer 14

Hypoglossal nucleus

Question 15

CN XII function

Answer 15

Motor to muscles of tongue (except palatoglossus)

Question 16

CN XII lesion

Answer 16

Ipsilateral tongue paralysis & atrophy

Question 17

CN V name

Answer 17

Trigeminal nerve

Question 18

CN V nuclei

Answer 18

• Nucleus of spinal tract of trigeminal (pain & temp)
• mesencephalic nucleus (proprioception)
• motor nucleus (mastication muscles)

Question 19

Peripheral branches of CN V

Answer 19

V1: ophthalamic (sensory)
V2: maxillary (sensory)
V3: mandibular (mixed)

Question 20

CN V function

Answer 20

Trigeminal
- sensory to face, scalp, teeth, most tongue, oral & nasal mucosa, dura mater & cerebral BVs
- motor to mastication muscles (masseter, temporalis, medial & lateral pterygoid muscles)

Question 21

CN V lesion

Answer 21

Trigeminal neuralgia (tic douloureux)
facial anesthesia/numbness
Inability/difficulty biting down with jaw deviation to same side

Question 22

Examination of CN V lesion

Answer 22

Touch by cotton swab
Pain by pinprick
Temperature
Corneal reflex
Jaw reflex
Masticatory movements

Question 23

CN VI name

Answer 23

Abducens

Question 24

CN VI nucleus

Answer 24

Abducent nucleus

Question 25

CN VI function

Answer 25

Extraocular movements (lateral rectus muscle)

Question 26

Examination of CN VI

Answer 26

Lateral eye movements (abduction)

Question 27

CN VI lesion

Answer 27

Diplopia (double vision), medial strabismus

Question 28

Levels of CN V

Answer 28

1. Nucleus of spinal tract of trigeminal - midpons-C5 2. Chief sensory nucleus - midpons 3. Mesencephalic nucleus - midpons-midbrain 4. Motor nucleus - midpons

Question 29

Where does CN V exit?

Answer 29

Trigeminal nerve: Midpons

Question 30

Level of CN VI

Answer 30

Abducens: tegmentum of lower pons at level of facial colliculus

Question 31

Where does CN VI exit?

Answer 31

Pontemedullary junction between basilar pons & pyramid

Question 32

CN VII name

Answer 32

Facial

Question 33

CN VII nuclei

Answer 33

Facial nucleus (motor) Nucleus of solitary tract (taste & parasympathetic) Superior salivatory nucleus (parasympathetic)

Question 34

Levels of CN VII

Answer 34

Facial nucleus: Lower pons at level of facial colliculus

Question 35

Where does CN VII exit?

Answer 35

Cerebellopontine angle

Question 36

CN VII peripheral branches

Answer 36

Temporal Zygomatic Buccal Marginal Mandibular Cervical (The Zebra Bit My Cat)

Question 37

CN VII function

Answer 37

Facial: - motor to muscles of facial expression - taste from anterior 2/3 of tongue via chorda tympani - parasympathetic to lacrimal, serous & mucous glands of nasopharynx, and submandibular & sublingual glands via chorda tympani

Question 38

Examination of CN VII

Answer 38

Facial expression movements & taste

Question 39

CN VII lesion

Answer 39

Bell’s Palsy: LMN type facial paralysis (hyperacpusis, unilateral facial paralysis with inability to wrinkle forehead, raise eyebrow, shut Ike, tear flow over sagging lower eyelid, loss of lost from anterior 2/3 of tongue

Question 40

CN VIII name

Answer 40

Vestibulocochlear

Question 41

CN VIII nuclei

Answer 41

- vestibular nuclei (4) - cochlear nuclei

Question 42

CN VIII function

Answer 42

Balance & equilibrium Hearing

Question 43

CN VIII lesion

Answer 43

Vertigo, nystagmus, vomiting Loss of hearing

Question 44

CN IV name

Answer 44

Trochlear

Question 45

Nucleus of CN IV

Answer 45

Anterior part of periaqueductal gray at level of inferior colliculus

Question 46

Where does CN IV exit?

Answer 46

Inferior to inferior colliculi after nerve fibers decussation in superior medullary velum

Question 47

CN IV function

Answer 47

Innervation of superior oblique muscle

Question 48

Examination of CN IV

Answer 48

Turn Eyeball into down & in position

Question 49

CN IV lesion

Answer 49

Inability and double vision when looking down & in

Question 50

CN III Name

Answer 50

Oculomotor

Question 51

CN III nuclei

Answer 51

Anterior portion of periaqueductal gray at level of superior colliculus - motor - edinger-westphal (parasympathetic)

Question 52

where does CN III exit?

Answer 52

Interpeduncular fossa

Question 53

CN III function

Answer 53

- Motor to all extraocular muscles except lateral rectus & superior oblique (Medial rectus, superior rectus, inferior rectus, inferior oblique & levator palpebrae superioris) - parasympathetics to sphincter pupillae (constriction) & ciliaris (accomodation)

Question 54

CN III lesion

Answer 54

Ptosis Lateral strabismus Mydriasis (enlarged, unresponsive to light pupil) Cycloplegia (enlarged, unresponsive to accommodation pupil)