Transcript Period 5 THE SKULL!

Miranda Kadis, Divya Agarwal, Max
Lee
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Functions:
1. Protect the brain
2. Support delicate sense organs involved with
vision, hearing, balance, olfaction and
gestation
3. Eating (Jaw)
4. Aid with sensory information (eyes, ears,
nose, mouth)
5. Aid with communication (mouth, facial
expressions)
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Frontal – air filled to make the bone lighter;
produces muscous to clean and moisten nasal
cavities
Ethiodal - lightens ethiodal bone
Sphenoidal – lightens sphenoidal bone
Maxillary – lighten the portion of the maxillary
bones above the embedded teeth.
forms forehead and roof of
orbits (body recesses that contain eyes)
 Supraorbital foramen - opening that pierces
ridge above each orbit forming passageway for
blood vessels and nerves
 above orbit, there are frontal sinuses that
make the bone lighter and produce mucus.
 infraorbital foramen - opening for a major
sensory nerve from the face
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Paired left and right
Posterior to frontal bone
Form roof and superior walls of cranium
Each has a superior and inferior temporal line
to which temporal muscle is attached
joined together by midsagittal suture, with the
frontal bone anteriorly by coronal suture, with
the occipital bone by lambdoid suture, with
temporal bone by squamosal and
parietomastoid sutures
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forms posterior and inferior portions of
cranium
joins two parietal bones at the lambdoid suture
foramen magnum connects cranial cavity with
spinal cavity
on either side of this are the occipital condyles
- joint between skull and vertebral column
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Below parietal bones
contact parietal bones along the squamous suture on each side
Anatomical landmarks:
○ External acoustic canal leads to the typanum (eardrum)
○ Eardrum separates external acoustic canal from middle ear
cavity which contains ear bones
○ anterior to acoustic canal is a transverse depression
(mandibular fossa) which marks the joint with lower jaw
○ mastoid process is posterior and inferior to entrance to
acoustic canal
■ provides a site for attachment of muscles that rotate or
extend the head
○ styloid process attached to ligaments that support hyoid
bone and anchors muscles associated with tongue and pharynx
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forms part of floor of cranium and unites
cranial and facial bones and braces sides of
skull
contains pair of sinuses called sphenoidal
sinuses
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anterior to sphenoid bone
forms part of cranial floor, contributes to
medial surfaces of the orbit of each eye, and
forms roof and sides of nasal cavity.
ridge called crista galli projects above superior
surface of ethmoid
lateral portions contain ethmoidal sinuses
which drain into nasal cavity
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maxillary bones joined with all other facial
bones except mandible
form floor and medial portion of rim of orbit,
walls of nasal cavity, and anterior roof of
mouth
contain maxillary sinuses – lighten portion of
bones above teeth
palatine bones form posterior surface of roof
of mouth
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inferior margin of vomer joins with palatine
bones
supports partition that forms part of nasal
septum along with ethmoid bone
one each side of skull zygomatic bones
join with the frontal bone and maxilla to
complete lateral wall of orbit
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nasal bone forms bridge of the nose midway
between the orbits and joins with the frontal
bone and maxillary bones
lacrimal bones within orbit on medial surface
inferior nasal conchae project from lateral
walls of nasal cavity
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nasal complex includes bones that form
superior and lateral walls of nasal cavities
nasal septum separates left and right portions
of nasal cavity
mandible is bone of lower jaw
anterior coronoid process is the attachment
point for temporalis muscle (muscle that closes
jaw)
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small and u-shaped
● suspended below skull
● serves as a base for muscles associated with
the larynx, tongue, and pharynx
● supports and stabilizes portions of larynx
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Common causes: car crashes, collision with
object, assaults, falls
Falls most common with children, collisions
most common with athletic teens
Head injuries are incredibly dangerous
May lead to permanent disability, mental
impairment, or death.
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Concussions: most common (TBI) – brain is
shaken hard enough to bounce against skull
Contusion: bruise on the brain that can cause
swelling
Hematoma: internal bleeding that causes a clot
in the brain
Skull fracture: sometimes a piece of bone may
cut the brain and cause internal bleeding
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Sutures=flexi
ble joints
(fibrous –
also known
as
fontanelles)
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When a baby is growing, the brain grows faster
than the skull
At birth: cranial bones are connected by
fontanels (“soft spots”)
They permit distortion of the skull without
damage
The skull has four joints.
Two that attach the
mandible to the temporal
bone and two that attach
the atlas vertebra to the
occipital bone.
 The mandible and
occipital condyle joints
are hinge joints.
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