AXIAL: Calvarium Flashcards
What are the two major divisions of the skull?
- Calvarium / Cranium
- Cranial base / Facial bones
A mnemonic for major bones of the calvarium?
STEP OF 8
S - Sphenoid
T - Temporal (2 bones)
E - Ethmoid
P - Parietal (2 bones)
O - Occipital
F - Frontal
8 - 8 major bones individually
The bone that forms the forehead
Frontal Bone (Squamous part of frontal bone)
This is the landmark for radiologic skull measurement ; inferior to the frontal bone, above the root of the nose
Glabella
Passageway of blood vessel that contributes to your eyes ; openings above the orbit
Supraorbital foramen
Thickened part which lie under the eyebrows ; where the forehead ends
Supraorbital margin
Forms most of the superior and lateral aspects of the skull
Parietal bone
This suture is between the frontal and parietal bone
Coronal suture
This suture is between the occipital and parietal bones
Lambdoid / Lambdoidal suture
This suture is between the temporal and parietal bones
Squamosal / Squamous suture
This suture is between the two parietal bones
Sagittal suture
Forms the inferolateral aspects of the skull and contribute to the middle cranial fossa
Temporal bone
What are the 3 major parts of the temporal bone?
- Squamous
- Tympanic
- Petrous
This is best viewed in lateral position
Temporal bone
This is formed when the zygomatic process of the temporal bone meets the zygomatic bone
Zygomatic arch
Wherein the condylar process of the mandible articulates with the mandibular fossa
Temporomandibular joint (TMJ)
This bone meets with the zygoma
Zygomatic process
where the sound enters the ear, thus enables sound waves to reach the eardrum
External Acoustic Meatus (EAM)
The 2 joints that connect your lower jaw to your skull ; collaboration of bone
TMJ
the thickest out of all the temporal bones
Petrous bone
This houses the middle and internal ear cavities
Petrous bone
This supports the temporal brain
Middle cranial fossa
This is the most lateral foramen which serves as a passageway for the jugular vein
Jugular foramen
This is located exactly between the petrous temporal and sphenoid ; most medial portion
Foramen lacerum
This is anterior to the jugular foramen which allows transmission of carotid artery into the cranial cavity
Carotid canal
This transmits cranial nerves
Internal acoustic meatus
What specific cranial nerves are passing through the internal acoustic meatus?
C7 and C8
Round opening in the floor of the middle cranial fossa, located between the superior orbital fissure and foramen ovale
Foramen rotundum
Oval in shape and is an opening between the atria in the fetal heart ; serves as passageway of mandibular nerve
Foramen ovale
This is a foramen in the petrous bone which transmits 3 (nerve, artery, vein)
Foramen spinosum
What are the three transmissions from the foramen spinosum consists of?
- Middle meningeal artery
- Middle meningeal vein
- Nervous spinosus
- This acts as an anchoring site for some neck muscles and this can also be felt as a lump just posterior to the ear
- Dotted surface for air cells and air cavities
- Regulates temp. in the skull
Mastoid process
This is a needle-like process which is not just for neck attachment but also for tongue muscles
Styloid process
This is a bone found in the cranium that forms most of the skull’s posterior wall and base
Occipital bone
This supports the cerebellum of the brain
Posterior cranial fossa
This is considered to be the largest foramen found in the skull wherein the spinal cord passes through
Foramen magnum
Located on each lateral side of the foramen magnum wherein the C1 articulates
Occipital condyle
This is the most bulging part of the posterior skull ; little hump on the back of the head
External occipital protuberance
- Bat-shaped bone
- Keystone of the cranium, because it acts as a central wedge that articulates with all other cranial bones
- Contributes to the middle cranial fossa and orbits
Sphenoid bone
Forms the center of the sphenoid bone
Body
This houses the pituitary gland
Sella Turcica (or hypophyseal fossa of sella turcica)
Part of sphenoid bone found in the medial process that has a horn-like shape
Lesser wing
Part of the sphenoid bone that projects laterally
Greater wing
Part of the sphenoid bone in the interior portion which serves as an attachment for pterygoid muscles for chewing
Pterygoid process
- This also has a complex shape like the sphenoid bone
- Helps to form the anterior cranial fossa
- Forms part of the nasal septum and the lateral walls and roof of the nasal cavity
- Contributes to the medial wall of the orbit
Ethmoid bone
Forms the roof of nasal cavities ; floor of the anterior cranial fossa
Cribriform plate
Dura mater of the brain is attached to this structure which helps secure the brain in the cranial activity
Crista galli
Inferior portion of the ethmoid bone, which divides the nasal cavity from right to left
Perpendicular plate
This is also known as wormian bones
Sutures
This group of bones are best viewed on lateral position
Temporal bones
