Download Skull - Dr. Steve W. Altstiel

Skull
Human Anatomy & Physiology
“Skeletal System”
Dr. Steve W. Altstiel
Naples High School
A. Skull
• The skull has 22 bones (some doubled), so 14
different named bones.
1. Cranium – part that holds and protects the
brain… composed of 8 bones held together by
sutures.
a. Sutures
1)
2)
3)
4)
Coronal
Sagittal
Lambdoidal
Squamous
Skull
b. Fontanels – incomplete sutures in infants – allow
bones to slide during birth – allow for growth of the
brain.
c. Sinuses – air-filled cavities – function to lighten bones
– open into the nasal cavity.
d. Foramina – “canals” – holes in the skull to allow
passage of nerves, vessels, and spinal cord.
e. Bones – 8 – (actually six named)
Skull (8 Bones)
1) Frontal bone – found on forehead and the roof of
the orbits (eye sockets).
2) Parietal bones – 2 – make up top and upper sides
of the skull.
3) Occipital bone – 1 – makes up a large part of the
back and bottom of the skull.
o Foramen magnum – “Big hole” – spinal cord attached
to the brain and arteries pass through this hole.
o Occipital condyles – articulates with the first
vertebra.
Skull (8 Bones)
4) Temporal bones – 2 – on sides of the skull.
o Ear – external auditory canal, middle and inner ear.
o Mandibular fossa - <--> (articulates with) mandible.
o Mastoid process – muscle attachment – contains
sinuses.
o Styloid process – attachment for bone and muscle.
o Zygomatic process - <--> zygomatic bone & chewing
muscle.
o Carotid canal – internal carotid artery passage.
o Jugular foramen – interior jugular and cranial nerve
passage.
Skull
5) Sphenoid bone - <--> all the other cranial bones.
Looks like a bat.
o Optical canal – optic nerve passage for attachment to
brain.
o Superior orbital fissure – passage for cranial nerves and
nerves that move the eyeball.
o Sella turcica – place that holds the pituitary gland.
6) Ethmoid bone – hard to see. Located in front of the
sphenoid bone. Largely involved with the nasal
cavity and orbit.
o Cribiform plate – “sieve-like” – passage for olfactory
nerves allowing you to smell.
o Perpendicular plate – forms the upper nasal septum.
o Superior and middle nasal conchae – shelves found in
nasal cavity on either side of the perpendicular plate.
Skull
2. Facial bones – 14 – only eight are named – 13 are
immovable, and 1 is moveable. Overlap of cranial
and facial bones make up the orbit and nasal cavity
1) Maxillary bones (maxillae) – upper jaw and also lower
part of the orbit.
o
o
Palatine process (anterior hard palate) – makes up the anterior
hard palate and separates the nasal cavity from the mouth.
Alveolar process – holds upper teeth in its sockets.
2) Palatine bones – make up posterior hard palate.
3) Zygomatic bones - cheek bones.
o
Temporal process (of the zygomatic bone) <--> zygomatic
process (of the temporal bone).

Forms the Zygomatic Arch.
Skull
4) Lacrimal bones – part of the orbit – contains the tear
duct.
5) Nasal bone – 2 – forms the bridge of the nose.
6) Vomer – makes up part of the nasal septum (lower).
7) Inferior nasal conchae – 2 – part of the lateral nasal wall.
8) Mandible – only moveable bone – make up the lower
jaw.
o
o
Body
Ramus – extension upward.
o
o
o
Mandibular condyle - <--> the mandibular fossa of the temporal
bone – forms the temporal mandibular joint.
Coronoid process – muscle attachment.
Alveolar arch – sockets for lower teeth.
B. Hyoid – U-shaped bone – does not <--> the rest of
the skeleton – attachment for tongue and larynx.