Lecture 23 - Skull and Cranial nerves Flashcards
The skull consists of __ bones united at _____
22 bones
united at sutures
the facial bones ___ off the cranium
hang
What are the conents of the canial cavity?
brain, meninges, cranial nerves, arteries, veins, venous sinuses
The roof of the cranial cavity is the …
cranial vault
Where is the sphenoid bone
spans across the floor
wher is the ethomoid bone?
midline near eye sockets
what are the cheekbones?
zygomatic bones
what is the top part of the jaw?
maxilla
where is the coronal suture?
between frontal and two pariental
the saggital suture is between..
the two parietal bones
where is the lambdoidal suture?
between two parietal and occipital bones
The floor of the cranium has ___ levels, what are they?
3 levels - like a staircase:
- anterior cranial fossa
- middle cranial fossa
- posterior cranial fossa
What are the structures that make the anterior cranial fossa?
frontal bone
lesser wing of sphenoid (posteriorly) - important as it has lots of holes for vessels
orbital plates of the frontal bone (floor)
Cribiform plate of ethmoid (floor)
What are the structures that make the middle cranial fossa?
lesser wing ofsphenoid (ant)
petrous portion of temporal bone (posterior)
lateral:
temporal bone
greater wing of sphenoid
pariteal bone
The sphenoid bone forms where? what does it look like
anterior and middle cranial fossa, is right in the middle of the skull
connects orbits with cranial cavity
looks like a bi-plane - two wings (lesser and greater)
gap b/w the wings behind the eyeballs - BVs can go through here…
What are the structures that make the posterior cranial fossa?
petrous portion of temporal bone (ant
floor:
Basilar, condylar and squamous portion of the occipital bone
the mastoid process of the temporal bone
The cranial nerves supply
somatic and visceral motor, autonomic
most cranial nerves arise from the …
brainstem
CN1=
olfactory
CN2 =
optic
CN3 =
oculomotor - movement of the eyeballs
CN4 =
trochlear - also moving eye balls
CN5 =
trigeminal - senesation on face and chewing
CN6 =
Abducent - eyeball movement
CN7 =
Fascial - smile , move faces
CN8 =
Vestibulocochlear - hearing and balance
CN9 =
Glossopharyngeal - sensory to throat
CN10 =
Vagus - parasympathetic to body
CN11 =
Accessory - shrug our shoulders and turn our head
CN12 =
Hypoglossal - tounge’s move
What is the mnemonic for the CNs
oh oh oh to touch and feel very good velvet, AH
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducent, Facial,
Vestibulocochlear (formerly Auditory), Glossopharyngeal, Vagus, Accessory, Hypoglossal
Use your Trigeminal (CN5) nerve and…
masticate!
Which nerve are purely sensory?
CN1, CN2, CN8
Which nerve are purely motor?
CN3, CN4, CN6, CN11, CN12
Which nerve are mixed?
CN5, CN7, CN10
where does CN1 exit the skull?
Cribiform plate
where does CN2 exit the skull?
optic canal - within the sphenoid bone
There are _ extraocular muscles?
6
rectus muscles sup inf medial lateral
oblique muscles - from the side
CN3 goes to all extrocular muscles except..
superior oblique, lateral rectus
which cranial nerve goes to the superior oblique extrocular muscle
CN4 - trochlear
which cranial nerve goes to the lateral rectus extrocular muscle
CN6 - adjucent
where does CN3,4,6 exit the skull?
superior orbital fissure
CN3,4,6 are responsible for moving the …
eyeball
What does CN5 do?
somatic sensory +
motor to muscles of mastication
three branches covering the face
Where do the branches of CN5 exit the skull?
V1 - superior orbital fissure
v2 - foramen rotundum
v3 - foramen ovale
The facial nerve is a ___ nerve
mixed
What does CN 7 do?
Motor: muscles of facial expression
visceral efferent : glands eg. lacrimal (tears), sublingual gland
visceral sensory: taste to anterior 2/3 tongue
somatic sensory
where does What does CN 7 exit the sckull
internal acoustic meatus
what the fascial motor terminal branches ?
pinky to forehead, going down:
temporal zygomatic bucal marginal mandibular cervical
CN8 - what does it do?
Hearing and balance (special sensory)
Where does CN8 exit the skull?
internal acoustic meatus
CN9 - what does it do?
“does everything”
Glossopharnygeal
“Back of the throat”
sensory from tongue (post. 1/3), pharynx, middle ear and carotid body
taste: post. 1/3 tongue
visceral motor: PS to parotid
motor: stylopharnges
Where does CN9 exit the skull?
jugular foramen
CN10 - what does it do?
visceral motor
motor to muscles of soft palate, phyarynx, larynx, upper oesophagus and 1 tongue muscle
somatic sensory: pharynx and larynx
visceral sensory: taste, general baro-receptors
Where does CN10 exit the skull?
jugular foramen
CN11 - what does it do?
provides motor input to sternomastoid and upper part of trapezius
Where does CN11 exit the skull?
Spinal acessory
Nucleus is in the upper 5-6 of cervical spinal cord
nerve enters cranium via foramen magnum
then travels with X root and exits jugular foramen
CN12 - what does it do?
motor to intrinsic and extrinsic mucles of the tongue - except one, which is dnone by CNX)
Where does CN12 exit the skull?
hypoglossal foramen
