Skull Flashcards
two functional subdivisions of the skull
neurocranium and viscerocranium
calvaria
dome like roof of neurocranium (skull)
cranial base
floor of neurocranium
eight bones that make up neurocranium
- frontal (on midline)
- ethmoid (on midline)
- sphenoid (on midline)
- occipital (on midline)
- temporal (occur as bilateral pair)
- parietal (occur as bilateral pair)
15 bones of viscerocranium
- mandible (singular on midline)
- ethmoid (singular on midline)
- Vomer (singular on midline)
- maxillae (bilateral pair)
- inferior nasal conchae (bilateral pair)
- zygomatic (bilateral pair)
- palatine (bilateral pair)
- nasal (bilateral pair)
- lacrimal (bilateral pair)
how does bone development differ in viscerocranium than neurocranium?
- Viscerocranium: bones develop in mesenchyme of embryonic pharyngeal arches
- Neurocranium: bones develop via
- intramembranous ossification of head mesenchyme from neural crest
- endochondrial ossification of cartilage (chondrocranium)
- or via more than one type of ossification
orbitomeatal plane
anatomical position of the skull
when inferior margin of orbit and superior margin of external acoustic meatus lie in same horizontal plane
AKA frankfort plane
what bones seen on superior view of skull?
frontal bone anteriorly, R and L parietal bones laterally, occipital bone posteriorly
bregma
intersection of sagittal and coronal sutures
lambda
intersection of lamboidal and sagittal sutures
what do frontal and parietal eminences indicate?
represent initial site of ossification of frontal bone and parietal bones
superior and inferior nuchal line
area of attachement for some neck and back muscles
metopic suture
sometimes present
between right and left frontal bones
what goes through zygomaticofacial foramen?
zygomaticofacial vessels and nerve
name these in the orbit
A- frontal, B ethmoid, C lacrimal, D palatine, E maxilla, f zygomatic, g sphenoid greater wing, h sphenoid lesser wing
what travels through supraorbital notch/foramen
supraorbital vessels and nerve
what is the infraorbital foramen for?
infraorbital vessels and nerve travel through it
communicates posteriorly with infra orbital canal and groove
What passes through superior orbital fissure
CN III, IV, VI, V1
what passes through inferior orbital fissure
V2, infraorbital vessels
what passes through optic canal
CN II, opthalmic artery
what passes through anterior and posterior ethmoidal foramen
anterior and posterior ethmoidal nerve, artery and veins
location of injection for local anesthesia of premolar maxillary teeth
canine fossa
what’s in anterior cranial fossa
frontal lobe
what’s in middle cranial fossa
temporal lobes
what’s in posterior cranial fossa
cerebellum and brainstem
which cranial fossa is the largest?
posterior cranial fossa is largest and deepest
What bones make up anterior cranial fossa
frontal, ethmoid, sphenoid
What bones make up middle cranial fossa
sphenoid, temporal, parietal
What bones make up posterior cranial fossa
temporal, parietal, occipital
what 4 areas of skull seen from lateral view
cranial vault, facial, infratemporal, mandible
what makes up cranial vault region
forehead and temporal region
what makes up facial region
zygomatic, orbital, nasal regions
describe temporal lines
- two curved lines that arch up and back from zygomatic process of frontal bone, travel across frontal bone and parietal bone then go down and forward on parietal bone to end on temporal bone
- superior limit of curved origin of temporalis muscle
pterion
H shaped junction of frontal, parietal, greater wing of sphenoid and temporal bones on lateral aspect of cranial vault
on what bone does the external auditory meatus come out of?
temporal bone
inion
AKA external occipital protuberance
part of occipital bone that sticks out in the back
what wraps around the styloid process?
tympanic plate wraps around it like a scroll
