SKULL
HUMAN SKULL
• Consists of 22
bones
• 8 of these bones
make up the
cranium
• 14 form the facial
skeleton.
• (also 6 tiny bones
in the middle ear)
PARTS OF THE SKULL
CRANIUM
• The cranium encloses
and protect the brain,
and its surface
provides attachments
for muscles that make
chewing and head
movements possible.
• There are 8 bones
that make up the
cranium.
•
•
•
•
•
•
Frontal Bone
Parietal Bones (2)
Occipital Bone
Temporal Bones (2)
Sphenoid Bone
Ethmoid Bone
FRONTAL BONE
• Forms the
anterior portion
of the skull above
the eyes,
including the
forehead, the
roof of the nasal
cavity and roof of
the orbits of the
eyes.
Parietal Bones
The parietal bones (2)
form, by their union,
the sides and roof of
the cranium. Each
bone is irregularly
quadrilateral in form,
and has two surfaces,
four borders, and four
angles.
Occipital Bone
• The occipital bone joins the
parietal bones.
• It forms the back of the skull and
the base of the cranium.
• A large opening on its lower
surface houses nerve fibers from
the brain that pass to the spinal
cord.
Temporal Bones
• A Temporal bones (2) on each side of
the skull joins the parietal bone along
a squamosal suture.
• Forms the sides and the base of the
cranium.
• House the internal ear.
• Notice how far it goes around the face
before it meets the zygomatic bone “cheek”
Temporal Bones
Sphenoid Bones
• The sphenoid bone is wedged between
•
•
•
•
several other bones in the anterior portion of
the cranium.
Helps form the base of the cranium, the
sides of the skull and the floors and sides of
the orbits.
This bone really has three different views…
Laterial—anterior to the temporal bone
Anterior- the back of the eye sockets
Inferior- looks like a butterfly.
Sphenoid Bones
• This bone really has three different
views…
• Lateral—anterior to the temporal bone
• Anterior- the back of the eye sockets
• Inferior- looks like a butterfly.
Sphenoid Bones
(Inferior View)
Ethmoid Bone
• Located in front of the sphenoid bone.
• Forms part of roof and walls of nasal
cavity.
• Floor of cranium, and walls of orbits.
• In the back of the orbital
cavity…longer bone
Ethmoid Bone
Facial Skeleton
• These bones
• The facial
provide basic
skeleton consists
shape of the face
of 13 immovable
• Attachments for
bones and a
muscles
that
move
movable lower
the jaw and
jaw bone.
control facial
expressions.
MANDIBLE
• Lower jaw bone
• A moveable bone
held to the cranium
by ligaments.
• Horseshoe-shaped
body with a flat
ramus projecting
upward at each end
MANDIBLE
MAXILLARY BONES
• They form the upper jaw.
• Together the form the keystone of the
face.
• They form anterior roof of mouth,
floors of orbits, and floor of nasal
cavity.
• Contains aleveolar process, maxillary
sinuses, palatine process.
Palatine Bones
• The L-shaped
palatine bones are
located behind the
maxillae.
• The horizontal
portions form the
posterior section of
the hard palate and
the floor of the
nasal cavity.
• The perpendicular
portions help form
the lateral walls of
the nasal cavity.
• This is easier too
see from the
bottom view of the
skull.
ZYGOMATIC BONES
• Responsible for the prominences
of the cheeks below and to the
sides of the eyes.
• Help form the lateral walls and the
floors of the orbits.
• Again notice where it meets the
temporal bone…called the
Zygomatic Arch or the Zygomatic
process of the Temporal
Lacrimal Bones
• A thin, scalelike
structure located in
the medial wall of
each orbit between
the ethmoid bone
and the maxilla.
• A groove in its
anterior portion
leads from the orbit
to the nasal cavity,
providing a pathway
for a channel that
carries tears from
the eye to the nasal
cavity.
NASAL BONES
• The nasal bones are long, thin, and
nearly rectangular.
• They lie side by side and are fused at
the midline, where they form the
bridge of the nose.
• These bones are attachments for the
cartilaginous tissue that forms the
shape of the nose.
Vomer bone
• The thin, flat vomer
bone is located
along the midline
within the nasal
cavity.
• Posteriorly, it
joins the
perpendicular
plate of the
ethmoid bone
Together they
form the nasal
septon.
Inferior Nasal Cavity
• The inferior nasal conchae are fragile,
scroll-shaped bones attached to the lateral
walls of the nasal cavity.
• Positioned below the superior and middle
nasal conchae of the ethmoid bone.
Foramen
• Foramen- An opening through a bone that
usually serves as a passageway for blood
vessels, nerves, or ligaments.
• You need to be able to identify the
following…
– Mental Foramen, Supraorbital Foramen
– Infraorbital Foramen, Foramen Magnum
Foramen
Supraorbital
foramen
(notch)
Infraorbital
foramen
Mental
foramen
Foramen
Foramen
magnum
Sutures
• Suture- an interlocking line of union
between bones
• You need to be familiar with the following
sutures….
–
–
–
–
Coronal Suture,
Lambdoidal Suture
Squamosal Suture
Sagittal Suture
Sutures
Coronal
suture
Squamous
suture
Lambdoid
suture
Sutures
Sagittal suture
Lambdoid
suture
Process
• Process- a prominent projection on a bone
• You need to familiar with the following…
– Styloid Process
– Mastoid Process
– Coronoid Process
Process
Mastoid process
Styloid process
Coronoid
process
Condyle
• Condyle- is a rounded process that usually
articulates with another bone
• You need to be familiar with the
following…
– Mandibular Condyle
– Occipital Condyle
Condyle
Mandibular
condyle
Condyle
Occipital
condyle
Inferior View
Palatine bone
Zygomatic bone
Vomer
Sphenoid bone
For Your Information
Zygomatic process
(Aka zygomatic arch
External acoustic canal
Ear Bones
• Malleus (2)- means hammer- shape of the bone
• Incus(2)- means anvil- shape of bone
• Stapes (2) means stirrup- shape of the bone
• Don’t worry about identification of these on the
skull…you cannot see them. Just recognize the
names as bones of the inner ear.
What have we learned so far??
Coronal Suture
Frontal Bone
Sphenoid Bone
Parietal Bone
Ethmoid Bone
Temporal Bone
Lacrimal Bones
Lamboid
suture
Squamous suture
Nasal Bone
Occipital bone
Zygomatic Bon
Maxilla
External Auditory
Canal
Mastoid Process
Styloid Process
Mandibular
condyle
Mandible
Mental Foramen
Coronoid
process