The
Skull
Skull Notes
• 22 bones
• 8 cranial – 13 facial
• interlocked along lines
called sutures
• Mandible: jawbone;
movable bone held
to the cranium by
ligaments
A. Cranium
• encloses and protects the brain
• attachment for muscles that
make chewing and head
movements possible
Sinuses
• air-filled cavities
• lined with mucous
membrane
• connected to nasal
cavity
• Function:
1. Reduce weight of the
skull
2. Resonant chambers for
voice quality
3. allows mucus to drain
into the nasal cavity
1.Frontal Bone (1)
• Anterior portion of the
skull above the eyes
including the forehead,
roof of the nasal cavity,
and the roofs of the
orbits
• orbit - bony sockets
of the eye
• supraorbital foramen
hole through which
blood vessels pass to
the forehead
frontal sinuses – one above each eye near the midline
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One frontal bone, starts as two
and fuses by age six
2. Parietal Bone (2)
• Located on each side of
the skull behind the
frontal bone
• Forms sides and roof of
cranium
sagittal suture –
fuse the right and left parietal
bones at the midline
coronal suture – where the
frontal and parietal bones join
3. Occipital Bone (1)
• Back of skull and base
of cranium
• lambdoidal suture –
where the parietal and
occipital bones meet
• foramen magnum -
large opening; nerve
fibers from the brain
pass through to spinal
cord
• occipital condyles
o rounded processes
on either side of
foramen magnum
o articulates with
atlas (first
vertebra)
4. Temporal Bone (2)
• Parts of the sides and
base of the cranium
• squamosal suture –
where temporal and
parietal bones meet
external auditory meatus / opening –
leads to inner parts of the ear
mandibular fossa – articulates with
the mandible
Mandibular
fossa
TMJ/TMD
temporal mandibular joint/disorder
• Cheek and temple pain.
• Painful clicking or popping sounds in the jaw joint
when opening or closing the mouth.
• Difficulty in opening the mouth fully or locking of the
jaw.
• Frequent radiating pain in the face, head, neck or
shoulders.
• Ear pain, Tinnitus (ringing in the ear) or hearing
problems.
• Dizziness.
• Swelling on the side of the face.
• Sudden significant change in the alignment of the jaw.
mastoid process of the Temporal Bone
– attachment for neck muscles
styloid
process –
attachment
for tongue
muscles
zygomatic process – extends anteriorly
from temporal bone, joins with zygomatic
bone to form cheek prominence
5. Sphenoid Bone
(1)
• Base of cranium
• sides of skull
• floor and sides of
orbits (pink in
image)
sella turcica – saddle-shaped
depression that holds the
pituitary gland
sphenoidal sinuses – 2
6. Ethmoid Bone (1)
• In front of
sphenoid
• Two parts – one
on each side of
the nasal cavity
cribriform plate – joins the two sides
Crista galli – attachment for
membranes that enclose the brain
Superior and middle nasal
conchae – support mucous
membranes
Perpendicular plate – projects
downward from the midline to form
nasal septum
ethmoidal sinuses - 6
•Frontal Bone (1)
•Parietal bone (2)
•Occipital bone (1)
•Temporal bone (2)
•Sphenoid bone (1)
•Ethmoid bone (1)
•Inferior nasal concha (2)
•Lacrimal bone (2)
•Vomer (1)
•Nasal bone (2)
•Maxilla (2)
•Palatine bone (2)
•Zygomatic bone (2)
•Mandible (1)