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Function(s) - of specific bones/features
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General Features
(of skeletal structure of head)
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Orbit(s)
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Definition: The cavity (cavities) in the skull
that contain the eye(s).
These cavities are formed from parts of the following
bones (also mentioned below): frontal, ethmoid, lacrimal,
maxillary, palatine, sphenoid, and zygomatic.
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Mechanical protection of the sensitive structures of
the eye(s), including the eye balls themselves, together
with the associated muscles, nerves, blood supply, and
other tissues.
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Paranasal Sinuses
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Definition: air-filled cavities lined with mucous
membranes located within some skull bones.
Paranasal sinuses include: frontal sinuses
and maxillary sinuses (one pair of each);
ethmoid sinuses (many spaces inside the
ethmoid bone); two sphenoid sinuses.
These are named after the bones in which they are located
- see diagram for positions of bones.
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Producing mucus;
Acting as resonating chambers - resulting
in personal speaking and singing sounds
that differ from person to person.
draining mucus out of the skull via the nasal cavities
as necessary (e.g. in case of over-production of mucus).
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Sutures
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Definition: The word "suture" has
meanings in both anatomy and surgery. In
the context of anatomy, a 'suture' is a
type of immovable joint found only between
skull bones and consisting of a small amount
of connective tissue between the bones.
There are several of these joints in the skull, examples
include: Coronal Suture (between frontal and parietal
bones); Lamboidal Suture (between the parietal and occipital
bones); and Sagittal Suture (between the two parietal
bones).
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These joints hold the bones of the skull together.
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Bones of the Cranium
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Ethmoid
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Floor of the cranium, inferior to the frontal bone
and anterior to the sphenoid.
Non-technically: Centre of the face, behind the nose.
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Forms part of the nasal cavity and the orbits.
Main support structure of the nasal cavity
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Frontal
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Forehead, extending down to form the upper surfaces
of the orbits. Anterior roof of the skull.
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Occipital
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Back and base of the cranium, forms the back of the
skull.
Non-technically: Lower back of the head.
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The occipital condyles (rounded surfaces at the base
of the occipital bone) articulate with the
atlas (first vertebra of the spine), enabling
movement of the head relative to the spine.
Has a large opening called the Foramen Magnus
which the spinal cord passes through.
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Parietal
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Top and sides of the cranium, posterior roof of the
skull.
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Sphenoid
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Anterior to the temporal bones and forms the base of
cranium - behind the orbitals.
Consists of a body, two "wings" and two "pterygoid
processes" (not labelled on diagrams) that project
downwards.
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Articulates with the frontal, parietal and temporal
bones.
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Temporal
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Sides of the skull, below the parietal bones, and above
and behind the ears
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Bones of the Face
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Hyoid
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In the neck, below the tongue (held in place by ligaments
and muscles between it and the styloid process of the
temporal bone).
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Supports the tongue, providing attachment sites for
some tongue muscles, and also some muscles
of the neck and pharynx.
(Commonly fractured during strangulation, so studied
in autopsies if strangulation suspected.)
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Lacrimal
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Behind and lateral to the nasal bone, also contribute
to the orbits.
(Smallest bones in the face.)
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Contain foramina for the nasolacrimal ducts (tear ducts).
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Mandible
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Known as the lower jaw bone. Also forms the chin and
sides of the face.
(Largest, strongest facial bone.)
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Bone into which the lower teeth are attached.
The only moveable facial bone; motion of
this bone is necessary for chewing food
(the first stage of the digestion process).
Each side of the mandible has a condyle and a coronoid
process. The condyle articulates with the temporal bone
to form the temporomandibular joint.
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Maxilla
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Upper jaw bone, which also forms the lower parts of
the orbits.
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Bone into which the upper teeth are attached.
Each maxilla contains a maxillary sinus that drains
fluid into the nasal cavity.
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Nasal
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Pair of small oblong bones that form the bridge and
roof of the nose.
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Palatine
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Back of the roof of the mouth (hence not illustrated
above). Small "L-shaped" bones.
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Form the bottom of the orbitals and nasal cavities,
and also the roof of the mouth.
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Turbinator
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Also known as Turbinate Bone and Nasal Concha.
These terms refer to any of three thin bones that form
the sides of the nasal cavity (not illustrated in the
diagrams above).
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Form the nasal cavities.
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Vomer
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Thin roughly triangular plate of bone on the floor
of the nasal cavity and part of the nasal septum.
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Separates the nasal cavities into left and right sides.
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Zygomatic
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Also known as Zygoma and Malar Bone.
Commonly (non-medically) referred to as
the
Cheek Bone because it forms the prominent part
of the cheeks. Also contributes to the orbits.
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Articulates with the frontal, maxilla, sphenoid and
temporal bones.
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