lecture 8 (1.0) cranial nerves

Question 1

how many cranial nerves?
where do they originate?

Answer 1

• 12 pairs
• originate from the brain (including brainstem)
• CN1 and 2 = anterior
• CN3 and 4= midbrain
• CN5 - 7 = pons
• CN8- 12 = medulla

Question 2

olfactory nerve (CN1)

Answer 2

function : smell
modality : sensory

anosmia : loss of smell

Question 3

optic nerve (CN2)

Answer 3

function : vision
modality : sensory

orbital hematoma : collection of blood inside the orbit

Question 4

oculomotor nerve (CN3)

Answer 4

function : **extrinsic eye muscles and levator palpebrae superioris** 
modality: motor

eyelid ptosis : upper eyelid droops downwards

Question 5

trochlear nerve (CNIV)

Answer 5

function : innervates superior oblique

modality : motor

vertical dipolpia : weakness of the downward movement of the eye

Question 6

trigeminal nerve (CNV)

Answer 6

• *ophthalmic branch (V1)**
• sensory from upper part of face
• *maxillary branch (V2)**
• sensory from middle part of face
• *mandibular branch (V3)**
• sensory anterior 2/3 of tongue and lower part of face. motor to muscles involved in chewing

Question 7

Abducens Nerve (CN6)

Answer 7

function : **innervates lateral rectus** 
modality : motor

6th nerve palsy

Question 8

facial nerve (CN7)

Answer 8

function : sensation to part of exterior ear
taste from anterior 2/3 tongue hard and soft palate
movement of muscles of facials expression
PNS : lacrimal gland, submandubular, sublingual glands, and mucous glands of mouth and nose
modality : sensory and motor

Question 9

Bell’s palsy

Answer 9

facial muscle weakness or paralysis

• symptoms : taste of anterior ⅔
• loss of facial expressions
• loss of feeling in the face

Question 10

vestibulocochlear nerve (CN8)

Answer 10

function : hearing and balance

modality : sensory

damage to CN8 : unsteady walking, nausea, vertigo, hearing loss

Question 11

glossopharyngeal nerve (CN9)

Answer 11

function : posterior ⅓ tongue (S), external ear (S), and middle ear cavity (S). Taste posterior ⅓ of tongue (S). Innervation of parotid gland (S). innervates stylopharyngeus (M)

modality : sensory and motor

Question 12

vagus nerve (CN10)

Answer 12

function : parasympathetic innervation of the internal organs. Muscle innervation of pharynx and larynx (M)

modality : sensory and motor

Question 13

accessory nerve (CN11)

Answer 13

function : innervates trapezius and sternocleidomastoid

modality : motor

damage to 11 : muscle weakness

Question 14

hypoglossal nerve (CN12)

Answer 14

function : innervates tongue muscles (except the palatoglossus)

modality : motor

damage to 12 : muscle weakness of the tongue