Cranial Nerve VII Facial nerve and Cranial nerve III

Question 1

Where does Cranial nerve VII emerge?

Answer 1

from brainstem at ventrolateral aspect of caudal pons near pontomedullary junction.

Question 2

nervus intermedius

Answer 2

smaller root of CN VII between root of CN VII and CN VIII contains GSA SA GVE GVA

Question 3

Large motor root of CN VII

Answer 3

SVE function

Question 4

Which fossa does CN VII emerge from?

Answer 4

posterior cranial fossa via the internal acoustic meatus same as CN VIII

Question 5

Where does CN VII go after leaving through internal acoustic meatus?

Answer 5

it courses through temporal bone, then exits via stylomastoid foramen

Question 6

Functions of facial nerve: SVE

Answer 6

Muscles of facial expression (and a few others)

Question 7

Functions of Facial nerve: GVE

Answer 7

General visceral efferents, parasympathetic inneration of lacrimal nasal palatine upper pharynx submandibular and sublingual glands

Question 8

Functions of facial nerve: GSA

Answer 8

General somatic afferents take in sensory info from portion of external ear

Question 9

Functions of facial nerve SA

Answer 9

Somatic afferents bring in taste info from anterior 2/3 of tongue and palate

Question 10

Fuctions of facial nerve: GVA

Answer 10

Recurrent fiber path that follows GVE fibers

Question 11

Where is the facial motor nucleus?

Answer 11

Pons

Question 12

Describe flow of info from corticobulbar fibers from motor cortex to innervation of facial muscles

Answer 12

Motor cortex -> facial motor nucleus (pons contralateral some ipsilateral) -> stylomastoid foramen -> facial muscles

Question 13

What would be associated with damage to RIGHT corticobulbar damage to upper motor neurons of CN VII?

Answer 13

Selective weakness of LEFT lower facial muscles.

Question 14

What would be associated with damage to right facial nerve?

Answer 14

Weakness in RIGHT upper and lower facial muscles

Question 15

Function of Orbicularis oculi?

Answer 15

closes the eye

Question 16

Describe blink reflex

Answer 16

CN-V fibers (GSA) carry pain info from cornea to CNS (spinal trigeminal nucleus) CN VII fibers (SVE) close the eye, blink is bilateral, spinal trigeminal fibers relay through recticular formation to bilateral facial motor nuclei

Question 17

Which Cranial nerves innervate skeletal muscle that control eye movements?

Answer 17

Oculomotor, Trochlear, Abducens

Question 18

Where do cranial nerves III, IV, and VI emerge from?

Answer 18

Superior orbital fissure (just like cranial nerve V) which is in the sphenoid bone by the way

Question 19

Which extraocular eye muscles does CN III innervate? (4)

Answer 19

Superior rectus, inferior rectus, medial rectus, inferior oblique

Question 20

Which extraocular eye muscle does CN IV innervate

Answer 20

superior oblique

Question 21

Which extraocular eye muscle does CN VI innervate?

Answer 21

Lateral rectus

Question 22

What is adduction?

Answer 22

movement towards midline

Question 23

What is abduction?

Answer 23

movement away from midline

Question 24

What is internal/medial rotation/ intorsion

Answer 24

12 o clock position moves towards nose

Question 25

What is external/lateral rotation/ extortion

Answer 25

12 oclock position moves away from the nose

Question 26

Visual axis v orbital axis

Answer 26

visual axis is set off from orbital axis by about 23 degrees

Question 27

Superior oblique (isolated)

Answer 27

Abducts, depresses and medially rotates eyeball. Attaches to posterior and superior to horizontal axis. Passes medial to vertical axis and attaches to superior aspect of globe, so it abducts

Question 28

Inferior oblique (isolated)

Answer 28

Abducts elevates and laterally rotates eyeball. attaches posterior and inferior to horizontal axis, depresses posterior aspect of globe so it elevates the eye. Passes medial to vertical axis and attaches to posterior inferior aspect of globe, so it abducts the eye.

Question 29

Superior rectus (isolated)

Answer 29

Elevates adducts and rotates eyeball medially. Passes medial to vertical axis and attaches to anterior aspect of globe, so it adducts the eye.

Question 30

Inferior rectus (isolated)

Answer 30

depresses, adducts and rotates eyeball medially. passes medial to vertical axis and attaches to anterior aspect of globe so it adducts eye.

Question 31

Medial rectus (isolated)

Answer 31

adducts eyeball

Question 32

lateral rectus

Answer 32

Abducts eyeball

Question 33

Intorsion of globe

Answer 33

muscles with medial pull above visual axis intort/medially rotate globe, so superior oblique and superior rectus

Question 34

Extorsion of globe

Answer 34

muscles with medial pull below visual axis extort/laterally rotate globe, so inferior oblique and inferior rectus

Question 35

when eye is fully adducted which muscles move it up and down?

Answer 35

Superior and inferior oblique, they are in parallel at this point and can be pure elevators and depressors.

Question 36

When eye is fully abducted which muscles move it up and down?

Answer 36

superior and inferior rectus

Question 37

Where is CN III nucleus?

Answer 37

in rostral midbrain at level of superior colliculus

Question 38

Besides the 4 extraocular eye muscles what other efferent effects does CN III have?

Answer 38

GSE for levator palpebrae superioris muscle which elevates superior eyelid. and parasympathetic fibers GVE that pass to constrictor muscle of pupil

Question 39

Are connections from oculomotor nucleus to inferior rectus, medial rectus, and inferior oblique contralateral or ipsilateral?

Answer 39

they are ipsilateral and leave as the oculomotor nerve through the superior orbital fissure

Question 40

What do neurons on contralateral oculomotor project to?

Answer 40

to contralateral superior rectus muscles

Question 41

From which oculomotor nuclei is the levator palpebrai superioris muscle innervated?

Answer 41

from bilateral oculomotor nuclei

Question 42

Where do GVE fibers that eventually innervate ciliary muscles and sphincter pupillae come from and what is their path

Answer 42

They come from Edinger westphal nucleus, these are preganglionic sympathetic fibers that synapse on ciliary ganglion which then become postganglionic fibers and the innervate the ciliary muscles and pupil sphincter