Cranial Nerve Overview Flashcards
How many cranial nerves are there?
12
Can you name the 12 cranial nerves in order?
1) olfactory
2) optic
3) occulomotor
4) trochlear
5) trigeminal
6) abducens
7) facial
8) vestibulocochlear
9) glossopharyngeal
10) vagus
11) accessory
12) hypoglossal
State whether each cranial nerve is sensory, motor or both.
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
What is gustation?
Taste
What does CN1 do?
Smell
What does CN2 do?
Vision / visual acuity
What does CN3 do?
Eye movements
What does CN4 do?
Eye movement
What does CN5 do?
Facial sensation, and movement of the jaw
What does CN7 do?
Factual movements and anterior 2/3 of tongue taste
What does CN8 do?
Hearing and balance
What does CN9 do?
Taste anterior 1/3 of tongue, swallowing
What does CN10 do?
Lots
What does CN11 do?
Trapezius and sternocleidomastoid muscles
What does CN12 do?
Protrudes tongue
What is the cribriform plate?
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.
What foramen does the olfactory nerve run through?
The cribriform plate
What foramen does the optic nerve run through?
The optic canal
Which nerves exit via the superior orbital fissure?
Cranial nerves 3, 4 and 6, as well as the ophthalmic branch of the trigeminal nerve (CN 5, branch 1)
What foramen does the maxillary branch of the trigemimal nerve exit through?
The foramen rotundem
What foramen does the mandibular branch of the trigemimal nerve exit through?
The foramen ovale
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?
Medial = foramen lacerum
= internal carotid artery passes by here (NOT through!)
Lateral = foramen sinosum
= middle meningeal artery travels through here
Which cranial nerves race, through the internal acoustic meatus?
CN 7 and 8
Which foramen do cranial nerves 9, 10 and 11 pass through?
The jugular foramen
What foramen does CN12 exit through?
Then hypoglossal canal
What is the name given to the dural fold that runs sagittally down the brains longitudinal fissure, separating its hemispheres?
The falx cerebri
What is the name given to the dural fold that runs sagittally between the cerebella longitudinal fissure, separating its hemispheres?
Falx cerebelli
What is the name for the extension of dura which separates the cerebellum from the occipital lobes?
Tentorium cerebelli
What is the name of the point where the falx cerebri attaches anteriorly to the skull?
The Crista galli
Where is the crista galli attached to?
It is part of the ethmoid bone and it’s cribriform plate
Where do the dural sinuses eventually drain to?
The internal jugular vein
What does the internal jugular vein exit the skull through?
The jugular foramen
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?
The sphenoid bone
The pituitary/hypophyseal fossa
The sella turcica
What is the name of the crossing over of the optic nerves above the pituitary?
The optic chiasm
What is the name of the sinus which lies laterally to the pituitary gland?
The cavernous sinus.
Which nerves and arteries pass through the cavernous sinus?
The internal carotid artery
CN3, 4, 5 (branches 1 and 2) and 6
Through what does the internal carotid artery enter the skull?
The carotid canal
What is the pteranodon region?
The area where the temporal, sphenoid, parietal and frontal bones meet
What is important about the pterion region?
It is an area of weakness and is in line with the path of the middle meningeal artery.
What does CN6 do?
Eye movement
What X2 arteries predominantly make up the circle of Willis and where do they arise from?
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
Which vessels join the major ones previously mentioned to complete the circle of Willis?
The anterior and posterior communicating arteries
What is the clinical significance of the circle of Willis?
Anything outside the circle is an anatomical end artery
What are the names of the medial and lateral plates of bone that extend down from the sphenoid bone?
The pterygoid plates
How many extra-occultation muscle of the eye are there?
How many do which movements?
X7 in total
X6 = control eye movement X1 = controls eye lid elevation
Name the eye muscles involved in eye movement.
There are:
Rectus muscles = superior = inferior = lateral = medial
Oblique muscle
= superior
= inferior
What is the name of the muscle responsible for eye lid elevation?
Where does this muscle attach from and to?
What is its innervation?
Levator palpabrae superious
It attaches from the lesser wing of the sphenoid bone to the upper eyelid
CN3 (occulomotor)
What is the innervation of the muscle of eye movement?
All = CN3 (occulomotor)
EXCEPT
Lateral rectus = CN6 (abducens)
Superior oblique = CN4 (trochlear)
Which part of the eye do the rectus muscles attach to?
The sclera
Where does the superior oblique eye muscle arise from and attach to?
What route does this muscle take?
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
Where does the inferior oblique eye muscle arise from and attach to?
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)
Which salivary glands are supplied by which nerves?
Sublingual and submandibular = facial
Parotid = glossopharyngeal
The facial nerve travels through the internal acoustic meatus, but where does it exit the cranium?
Through the stylomastoid foramen
What are the X5 terminal branches of the facial nerve?
Where does the facial nerve unusually branch into these terminal branches?
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!
