Describe the frontal bone
It starts from the coronal suture superiorly on the skull and moves all the way down to the nasion (beginning of the nasal bone).
Posteriorly horizontal projection into the orbit- forms the roof.
laterally forms the frontozygomatic suture with the zygoma.
Forms part of the anterior cranial fossa
also houses the frontal sinus.
Specific landmarks:
Glabella- bump above the nose between eyebrows
Supraorbital margin- eyebrows
Supraorbital Notch- foramen for neurovascular supply to the scalp.
Describe the Parietal Bone.
Pair of bones separated by the sagittal suture.
Forms the roof and lateral walls.
Landmarks on the inner surface:
Grooves made from the middle meningeal artery.
Parietal tuberosity: a small prominence.
Describe the Occipital Bone.
Starts from the lambdoid suture all the way inferiorly to the clivus/basisphenoid.
Makes up the entire posterior cranial fossa.
Landmarks:
Posterior
It has this ridge that forms the external occipital protuberance.
Lateral to the EOP, we would find the superior nuchal line,
and the inferior one, inferiorly to it.
inferior
Has a big hole called the foramen magnum, in the base of the skull where the spinal cord runs through.
lateral to this we would find the occipital condyle
posterior to this is the condylar canal
and “anterior” and medial to it we would find the hypoglossal canal.
Describe the Sphenoid Bone.
Located in the middle cranial fossa.
Superiorly:
Central body- Tuberculum and Dorsum sellae
in between these them we would find the hypophyseal fossa (Pituitary gland)
You can also note the Foramen spinosum, ovale, and rotundum, starting laterally and posteriorly to the medial and anteriorly.
The lesser wing gives rise to the anterior clinoid process and the Dorsum sellae gives rise to the posterior clinoid process.
The orbital canal is located between the Tuberculum sellae and the lesser wing.
Anteriorly
The supraorbital fissure is formed between the greater and lesser wing.
Divided by the sphenoid crest is the sphenoid sinuses.
inferiorly
medial and lateral pterygoid processes
Describe the Ethmoid Bone.
Located in the anterior cranial fossa.
Superiorly
Crista gali separates the Cribiform plate
The Cribiform plate is perforated with olfactory foramen.
The Ethmoid labyrinths are located lateral to the cribriform plate. Contains the Ethmoid air cells.
Anteriorly
Crista Gali gives rise to the Perpendicular plate and forms the nasal septum.
Describe the Temporal bone
The petrous part is located in the middle cranial fossa.
Laterally
Squamous- flat and thin. Separated from the parietal via the squamous suture.
Coming of this region is the zygomatic process of the temporal bone
The external acoustic meatus is found inferior to the process.
Anterior to the EAM, the styloid process is located and posteriorly the mastoid process is located.
Superiorly
The petrous is prominent.
The internal acoustic meatus is visible
the jugular foramen
Inferiorly
Between the mastoid and styloid process, is the stylomastoid foramen.
medial and anterior to the styloid process is the carotid canal.
more medial to the styloid process is the jugular foramen.
Describe the Nasal Bones.
Fuses to form the dorsum/bridge
Nasion.
Laterally articulates with the frontal process of the maxilla
Describe the Zygoma.
Cheek
lateral wall of orbit
Describe the Lacrimal Bone.
Thin
The medial wall of the orbit
between the ethmoid and Maxillary process
Vertical groove- Lacrimal sulcus- fossa that contains ducts that drains tears.
Describe the Maxilla.
Fusion forms the Anterior nasal Spine.
The floor of the orbit.
infraorbital foramen
inferior orbital fissure
alveolar fissure
Palantine body, horizontal projections
Describe the Mandible
External (Laterally to Medially)
the condylar process that lies posterior to the coronoid process.
Between them is the mandibular notch.
ramus
the angle
mental foramen
Interior (L-M)
Mandibular foramen
the mylohyoid line separating the fossa for the sublingual gland and submandibular gland.
the digastric fossa
Describe the Zygomatic Arch
Composed of the zygomatic process from the temporal bone and the temporal process from the zygoma.
Has a mandibular fossa inferiorly- articulation with the condylar process of mandible
Anterior to the mandibular notch, there is a bump- that prevents forward dislocation. The articular tubercle.
What are the boundaries of the foramen lacerum?
Irregular triangle-shaped
Anteriorly- the sphenoid bone
Laterally- the petrous of the temporal bone
medially- the occipital bone
Which bones make up the orbital?
Frontal- superior
Maxilla- medial
Zygoma-lateral
Sphenoid- lateral inner
palatine- medial inner
lacrimal-medial inner
Ethmoid-medial inner
Which bones contribute to the sinuses? Describe the structures these bones produce in the nasal cavity.
Frontal sinus
Ethmoid sinus- provides the: air cells, superior and medial nasal conchae, perpendicular plate
Maxillary sinus- inferior nasal conchae, larges, natural ostium
sphenoid sinus
Name the articulating surfaces of the temporomandibular joint TMJ.
Mandibular fossa on the zygomatic process of the temporal bone
Articular tubercle on temporal bone
Head mandible- condylar process
What are the ligaments that are found in the TMJ? Provide origins and insertions as well.
Lateral sphenomadibular-originates from the spine of the sphenoid bone, near the foramen ovale, and inserts on the lingula of the mandibular foramen
Lateral stylomandibular- originates from the styloid process of the temporal bone and inserts on the angle of the mandible
Which structures does the infratemporal fossa communicate with?
Temporal fossa- superiorly deep to the zygomatic arch.
orbit anteriorly through the inferior orbital fissure
Pterygopalatine fossa medially through the pterygomaxillary fissure
middle fossa through the foramen ovale and spinosum
What are the boundaries of the infratemporal fossa?
Anteriorly- maxilla
medially- lateral pterygoid plate and Eustachian tube
Laterally- TMJ
Superiorly- Greater wing of the sphenoid bone
Inferiorly- Mandible
What are the boundaries of the pterygopalatine fossa?
A- maxillary sinus
P- pterygoid
L- Pterygomaxillary fissure
M- perpendicular plate
I- Palatine bone
S- inferior orbital fissure
Which bones make up the nasal septum?
Vomer and perpendicular plate of the ethmoid bones.
Which bones make up the palate?
the horizontal process of the maxillary bone and the horizontal process of palatine bone.
