Cranial Nerve Overview

Question 1

How many cranial nerves are there?

Answer 1

12

Question 2

Can you name the 12 cranial nerves in order?

Answer 2

1) olfactory
2) optic
3) occulomotor
4) trochlear
5) trigeminal
6) abducens
7) facial
8) vestibulocochlear
9) glossopharyngeal
10) vagus
11) accessory
12) hypoglossal

Question 3

State whether each cranial nerve is sensory, motor or both.

Answer 3

1) olfactory = S
2) optic = S
3) occulomotor = M
4) trochlear = M
5) trigeminal = B
6) abducens = M
7) facial = B
8) vestibulocochlear = S
9) glossopharyngeal = B
10) vagus = B
11) accessory = M
12) hypoglossal = M

Question 4

What is gustation?

Answer 4

Taste

Question 5

What does CN1 do?

Answer 5

Smell

Question 6

What does CN2 do?

Answer 6

Vision / visual acuity

Question 7

What does CN3 do?

Answer 7

Eye movements

Question 8

What does CN4 do?

Answer 8

Eye movement

Question 9

What does CN5 do?

Answer 9

Facial sensation, and movement of the jaw

Question 11

What does CN7 do?

Answer 11

Factual movements and anterior 2/3 of tongue taste

Question 12

What does CN8 do?

Answer 12

Hearing and balance

Question 13

What does CN9 do?

Answer 13

Taste anterior 1/3 of tongue, swallowing

Question 14

What does CN10 do?

Answer 14

Lots

Question 15

What does CN11 do?

Answer 15

Trapezius and sternocleidomastoid muscles

Question 16

What does CN12 do?

Answer 16

Protrudes tongue

Question 17

What is the cribriform plate?

Answer 17

A sieve like structure in the ethmoid bone which supports the olfactory bulb and is a site of attachment of the meninges to the brain.

Question 18

What foramen does the olfactory nerve run through?

Answer 18

The cribriform plate

Question 19

What foramen does the optic nerve run through?

Answer 19

The optic canal

Question 20

Which nerves exit via the superior orbital fissure?

Answer 20

Cranial nerves 3, 4 and 6, as well as the ophthalmic branch of the trigeminal nerve (CN 5, branch 1)

Question 21

What foramen does the maxillary branch of the trigemimal nerve exit through?

Answer 21

The foramen rotundem

Question 22

What foramen does the mandibular branch of the trigemimal nerve exit through?

Answer 22

The foramen ovale

Question 23

What X2 foramen (which do not carry cranial nerves) sit behind the foramen ovale?

Which is medial and which is lateral?

What structures is each involved with?

Answer 23

Medial = foramen lacerum
= internal carotid artery passes by here (NOT through!)

Lateral = foramen sinosum
= middle meningeal artery travels through here

Question 24

Which cranial nerves race, through the internal acoustic meatus?

Answer 24

CN 7 and 8

Question 25

Which foramen do cranial nerves 9, 10 and 11 pass through?

Answer 25

The jugular foramen

Question 26

What foramen does CN12 exit through?

Answer 26

Then hypoglossal canal

Question 27

What is the name given to the dural fold that runs sagittally down the brains longitudinal fissure, separating its hemispheres?

Answer 27

The falx cerebri

Question 28

What is the name given to the dural fold that runs sagittally between the cerebella longitudinal fissure, separating its hemispheres?

Answer 28

Falx cerebelli

Question 29

What is the name for the extension of dura which separates the cerebellum from the occipital lobes?

Answer 29

Tentorium cerebelli

Question 30

What is the name of the point where the falx cerebri attaches anteriorly to the skull?

Answer 30

The Crista galli

Question 31

Where is the crista galli attached to?

Answer 31

It is part of the ethmoid bone and it’s cribriform plate

Question 32

Where do the dural sinuses eventually drain to?

Answer 32

The internal jugular vein

Question 33

What does the internal jugular vein exit the skull through?

Answer 33

The jugular foramen

Question 34

What bone contains a fossa which contains the pituitary gland? What is the name given to this fossa? What is overall name of this structure called?

Answer 34

The sphenoid bone The pituitary/hypophyseal fossa The sella turcica

Question 35

What is the name of the crossing over of the optic nerves above the pituitary?

Answer 35

The optic chiasm

Question 36

What is the name of the sinus which lies laterally to the pituitary gland?

Answer 36

The cavernous sinus.

Question 37

Which nerves and arteries pass through the cavernous sinus?

Answer 37

The internal carotid artery CN3, 4, 5 (branches 1 and 2) and 6

Question 38

Through what does the internal carotid artery enter the skull?

Answer 38

The carotid canal

Question 39

What is the pteranodon region?

Answer 39

The area where the temporal, sphenoid, parietal and frontal bones meet

Question 40

What is important about the pterion region?

Answer 40

It is an area of weakness and is in line with the path of the middle meningeal artery.

Question 41

What does CN6 do?

Answer 41

Eye movement

Question 42

What X2 arteries predominantly make up the circle of Willis and where do they arise from?

Answer 42

1) the vertebral arteries = from the subclavian = travel via the cervical spine transverse foramen = enter the skull via the foramen magnum = join to form the basilar artery which later bifurcates into X2 posterior cerebral arteries 2) middle cerebral arteries = branches of the internal carotid = internal carotid enters via carotid canal = internal carotid travels through cavernous sinus before bifurcating into the middle cerebral arteries = middle cerebral arteries also give branches to form the anterior cerebral arteries

Question 43

Which vessels join the major ones previously mentioned to complete the circle of Willis?

Answer 43

The anterior and posterior communicating arteries

Question 44

What is the clinical significance of the circle of Willis?

Answer 44

Anything outside the circle is an anatomical end artery

Question 45

What are the names of the medial and lateral plates of bone that extend down from the sphenoid bone?

Answer 45

The pterygoid plates

Question 46

How many extra-occultation muscle of the eye are there? How many do which movements?

Answer 46

X7 in total ``` X6 = control eye movement X1 = controls eye lid elevation ```

Question 47

Name the eye muscles involved in eye movement.

Answer 47

There are: ``` Rectus muscles = superior = inferior = lateral = medial ``` Oblique muscle = superior = inferior

Question 48

What is the name of the muscle responsible for eye lid elevation? Where does this muscle attach from and to? What is its innervation?

Answer 48

Levator palpabrae superious It attaches from the lesser wing of the sphenoid bone to the upper eyelid CN3 (occulomotor)

Question 49

What is the innervation of the muscle of eye movement?

Answer 49

All = CN3 (occulomotor) EXCEPT Lateral rectus = CN6 (abducens) Superior oblique = CN4 (trochlear)

Question 50

Which part of the eye do the rectus muscles attach to?

Answer 50

The sclera

Question 51

Where does the superior oblique eye muscle arise from and attach to? What route does this muscle take?

Answer 51

It arises from the body of the sphenoid and attaches underneath the superior rectus muscle on the sclera It passes through a trochlear on the way

Question 52

Where does the inferior oblique eye muscle arise from and attach to?

Answer 52

It arises from the orbital floor and travels under the eye to attach underneath the lateral rectus muscle (but passes over the top of inferior rectus)

Question 53

Which salivary glands are supplied by which nerves?

Answer 53

Sublingual and submandibular = facial Parotid = glossopharyngeal

Question 54

The facial nerve travels through the internal acoustic meatus, but where does it exit the cranium?

Answer 54

Through the stylomastoid foramen

Question 55

What are the X5 terminal branches of the facial nerve? Where does the facial nerve unusually branch into these terminal branches?

Answer 55

1) temporal branches 2) zygomatic branches 3) buccaneers branches 4) marginal mandibular branches 5) cervical branches In the parotid gland, unusual as facial nerve does not innervate this gland!