The Skull Flashcards
describe roles of skull or cranium - 3
encloses and protects
houses
Structural support
what does skull enclose/protect
brain - cns
what does skull house
organs and spaces relating to special senses of olfaction, vision, hearing, balance and taste
(associated with individual cranial nerves)
what does skull serve as structural support for
scaffolding for soft tissues of head and neck = attachment sites for muscles of mastication and muscles of facial expression
how many bones in skull
22
what are 2 categories of skull bones
neurocranium
viscerocranium
describe neurocranium
braincase
protects brain
8 bones
describe viscerocranium
bones of face and jaw
14 bones
name all neurocranium bones and describe - brief
frontal = forehead, unpaired, ONE
Parietal = paired, left and right, TWO
temporal = paired, l/r, around midline of face, TWO
occipital = unpaired, back of head (associated with vertebral column, spinal cord runs through), ONE
sphenoid = unpaired, ONE
ethmoid = unpaired, related to sense of smell, ONLY ONE
what are sutures
ways bones fused together
squiggly lines
solidly fused in adulthood
name and describe all neurocranium sutures
sagittal = connects 2 parietals, parallel to sagittal plane
coronal = frontal to parietals, parallel to coronal plane
lambdoid = connects parietals to occipital, tripartite lamdba structure
squamosal = parietal to temporal
pterion = junction of frontal, parietal, sphenoid and temporal bones
compare adult skull and neonates
adult = solid fibrous joints
Neonates = soft connective tissues = fontanelles, soft spots = grows as baby grows, brain grows, 7-9y/o = brain growth slows down
what is cranial fossa
regions
depressions in skull
name 3 cranial fossa
anterior
middle
posterior
describe anterior cranial fossa
frontal, ethmoid and sphenoid
frontal lobes or cerebrum = higher cognitive function
describe middle cranial fossa
sphenoid, parietal, temporal
temporal lobes of cerebrum = memory
describe posterior cranial fossa
occipital, parietal, temporal
cerebellum (motor functions) and brainstem , hindbrain
some sphenoid too but mostly ignore
describe anterior cranial fossa - gen
frontal bone contributes to roof of orbit (orbital plates)
describe anterior cranial fossa - ethmoid
ethmoid contributes to medial wall of orbit and nasal cavities
describe anterior cranial fossa - cristal galli
Processes that stick out
roosters crest
serves as attachment for meninges = sheet of ct that separates hemispheres
describe anterior cranial fossa - perpendicular plate
part of nasal septum
Contributes to nasal septum
air cells and conchae = pockets with air cells that warms up air, increases surface area of where we can have olfactory receptors
describe anterior cranial fossa - cribriform plate
has foramina for olfactory nerves
cranial –> nasal cavity
one on each side of crista galli
describe ant/mid cf - sphenoid general
keystone cranial bone - bridges ant and mid cf
articulates with ALL other bones of neurocranium and 5 in viscerocranium (zygomatics, palatines. vomer)
foramina for passage of several cranial nerves
blood supply to cranium and brain
describe ant/mid cf - sphenoid structures
lesser wing and greater wing
sella turcica with hypophyseal fossa (seat of saddle = pituitary gland, inferior surface of brain)
describe ant/mid cf - sphenoid orbit
Contributes to most posterior aspect of orbital plate
describe ant/mid cf - sphenoid body of sphenoid
pterygoid process with medial and lateral plates
little legs = muscles attach here (mastication and neck)
name parts of mid/post cf
temporal
parietal
Occipital
describe parts of mid/post cf = parietal
contributes to wall on the side
describe parts of mid/post cf = occipital
houses cerebellum and has brain stem
name parts of mid/post cf = temporal
squamous portion
petrous portion
describe mid/post cf = temporal squamous
very thin
wall of neurocranium
doesnt need to be thick
describe mid/post cf = temporal petrous
petrous portion = one of densest non tooth bones - bc auditory vestibular apparatus needs to be isolated = dampener and cushions
rocky ridge = in petrous portion, transition from mid to post cf
describe mid/post cf = temporal acoustic
tympanic portion associated with external acoustic meatus (allows sound in)
temporal –> tympanic portion and hits eardrum
components of inner ear within petrous temporal bone
what are cranial foramina
holes
describe cranial foramina - anterior cf
cribriform foramina in ethmoid - fibers from olfactory nerve
passing back into cranial cavity
name cranial foramina - posterior cf
internal acoustic meatus
jugular foramen
hypoglossal canal
foramen magnum
describe internal acoustic meatus - posterior cf foramina
fibers from auditory nerve - enters into cranial cavity
facial nerve also passes through this
describe jugular foramen- posterior cf foramina
venous drainage of cranial cavity
3 cranial nerves pass here
describe hypoglossal canal - posterior cf foramina
hypoglossal nerve - fibers to tongue
motor muscles in tongue
describe foramen magnum- posterior cf foramina
large
spinal cord
meninges
Vertebral column - end of brainstem, superior aspect of spinal cord enters skull here
blood vessels
name all foramina - middle cf
superior orbital fissure
optical canal
foramen rotundum
foramen ovale
foramen spinosum
foramen lacerum
describe superior orbital fissure - mid cf foramina
motor nerves of eye movement, ophthalmic nerve
bunch of nerves and neurovascular structures - movement of eye
describe optic canal - mid cf foramina
optic nerve - detects light
behind small portion of lesser wing of spenoid
describe foramen rotundum - mid cf foramina
round
Maxillary nerve
describe foramen ovale - mid cf foramina
oval
mandibular nerve
describe foramen spinosum- mid cf foramina
thorny
middle meningeal artery/vein
blood to brain and spinal cord
middle meningeal artery passes = blood to coverings of brain
describe foramen lacerum - mid cf foramina
torn
floor of carotid canal for internal carotid artery
sealed off with soft tissue - but not in model since ct degraded, forms floor of carotid canal = internal carotid passes into cranial cavity to supply brain with blood
describe mastoid process
Attachment of sternocleidomastoid
describe styloid process
site of attachment of muscles
describe stylomastoid foramen
between mastoid and styloid process
facial nerve exits to reach muscles
name all 14 bones of viscerocranium
1 maxilla
2 maxilla
3 nasal
4 nasal
5 lacrimal
6 lacrimal
7 zygomatic
8 zygomatic
9 palatine
10 palatine
11 inferior nasal concha
12 inferior nasal concha
13 vomer
14 Mandible
describe maxilla - viscerocranium
TWO
superior teeth
upper jaw
bony palate
nose
describe nasal - viscerocranium
TWO
nose bridge
describe lacrimal - viscerocranium
TWO
medial orbital plate - tear ducts
has hole = drains tears into nasal cavity
describe zygomatic - viscerocranium
TWO
cheek bones
lateral wall of orbit
associated with neuro and viscero cranium
describe palatine - viscerocranium
TWO
bony palate
Posterior to maxilla
describe inferior nasal concha - viscerocranium
TWO
nasal cavity
describe vomer - viscerocranium
nasal septum
along with ethmoid and cartilaginous part
describe mandible - viscerocranium
lower jaw
describe zygomatic arch - viscerocranium
Temporal process of zygomatic bone (sends 2 processes back) to zygomatic process of temporal bone (send 2 processes forwards)
to each other
processes form zygomatic arch
