14 - Bones of the Skull Flashcards
What regions is the skull divided into?
The mandible
The cranium
The calotte
The neurocranium
What are the functions of the skull?
- Articulates with the superior facet of the the C1 vertebrae.
- Protects the brain.
- Supports the fleshy features of the face.
- Acts as an anchor apparatus for mastication.
What are the sutures of the neurocranium?
Coronal, Sagittal, lambdoid, Squamosal.
Coronal Suture
Between the frontal and the 2 parietal bones.
Sagittal Suture
Between the 2 parietal bones.
Lambdoid Suture
Between the occipital and parietal bones.
Squamosal Suture
Where the temporal articulates with the frontal parietal and occipital bones.
What are the cartilaginous precursors in developing cranial bones known as?
Fontanelles
What are the bones of the neurocranium?
Frontal, Parietal, Occipital, Temporal, Sphenoid, Ethmoid
The frontal bone
- Superior aspect of the skull, it encloses the brain.
- Forms the anterosuperior aspect of the cranium in 4 parts:
1- The squamous part- largest compartment which forms the shape of the forehead.
2&3 - The orbital parts - two triangular shaped flat plates extending posteriorly from the supraorbital margin.
4- The nasal part - A small area that projects inferiorly between supraorbital margins, acts as an area of articulation for the nasal bones and front of the maxilla.
Parietal Bones
- They sit on the left and right side of the head.
- There are many meningeal grooves on the inside.
Occipital bone
- On the posterior side of the cranium.
- There are 3 muscle attachment sites which makes the surface rough.
What is the foramen magnum?
A hole in the occipital bone which allows the brain to communicate with the rest of the spinal cord.
What are the cerebella fossae?
The 4 indents on the anterior side of the occipital bone.
Temporal bones
- Located on the lower lateral walls of the skull behind the ears.
Where does the eardrum sit in the head?
On the outer area of the external occipital meatus.
Where are the air cells located?
In the temporal bone specifically the mastoid process.
Shenoid Bone
- Consists of greater and lesser wings, a body and pterygoid plates below.
- The superior part of the bone encloses and protects the brain.
Ethmoid Bone
- Forms the top of the nasal aperture.
- It contains the cribiform plate with many holes allowing the nerves to come through.
What are the bones of the vicerocramium?
The Maxilla, zygomatic bones, palative bones, vomer, lacrimal bones, nasal bones, nasal conchae and mandible
The maxilla
- The bones that hold up the upper dentition.
- Forms the side of the one and inferior portion of the orbit.
- Incluces the alveolar process that holds up the teeth.
- Consists of the maxillary crypts.
Zygomatic Bones
The cheekbones, mark out the edge of the eye.
Vomer
Divides the nose into the left and right septum
Lacrimal bones
- Forms the most mdeial anterior portion of the orbit.
- The lacrimal groove on the side directs the tears into the nasal cavity.
Nasal bones
- Forms the top portion of the nose
- This is the only portion of the nose that protrudes out.
Nasal conchae
Sits on both the left and right side and is covered in the muscus membrane.
The Mandible
- Holds the lower dentition.
- Articulaltes with the temorla bone allowing us to talk, chew etc.
- Left and right condyle on either side.
What are the 3 bones of the middle ear?
The malleus, Incus and Stapes
What is the Hyoid?
A bone that sits withtin the throat and inferior to the mandible, it only has muscular attachments.
What are the 4 pared sinuses?
1-Frontal
2-Ethmoidal
3-Maxillary
4-Sphenoid
What do orbitial fissures allow the passage of?
Nerves, muslces, veins, arteries and the optic canal.
Where does the optic chiasma sit?
On the tuberculum sellae of the sphenoid.
