How many bones does the skull have? And how many in each category?
22 total
8 cranial and 14 facial
Name the 8 cranial bones.
1 frontal
2 parietal
2 temporal
1 sphenoid
1 ethmoid
1 occipital
Frontal bone: where is it found, what does it make up, has which sinus?
Anteriorly.
Makes up forehead and superior portion of bony orbit.
Contains paranasal/frontal sinus.
What is Nasion and why is it important?
Where frontal bone and nasal bone articulate.
IMPORTANT LANDMARK FOR MRI.
Parietal bone: makes up what. name it’s points, and what is special about it’s borders/articulations?
Makes up roof of the cranial cavity.
Creates highest point- vertex AND widest point- parietal eminence.
Borders/articulations are made of sutures.
Parietal eminence is
Widest part of cranium made by parietal bone.
Vertex is
Highest point of cranium made by parietal bone.
Temporal bone: makes up what area. has a process that makes up what, where are the meatus found and is seen how on MRI, articulates with what to make what joint?
Makes up temple area.
Has a zygomatic process that makes posterior portion of cheekbone.
Mastoid portion is posterior and inferior to the (EAM) External Auditory Meatus - contains mastoid process — black on MRI due to air cells.
Petrous portion contains the (IAM) internal auditory meatus.
Articulates with mandible to create temporomandibular joint.
Occipital bone: makes up which area, opening for what, where does it articulate?
Creates inferior/posterior portion of the base of the skull.
Has large opening for brainstem (foramen magnum).
Most anterior portion, clivus, articulates with sphenoid bone.
Sphenoid bone: shape, articulates with which bones, houses which gland, which sinus?
Butterfly shape (anchor for cranial bones).
Articulates with ALL other cranial bones.
Houses pituitary gland in sella turcica (saddle shape structure).
Has paranasal sinus.
Ethmoid bone: found where, has which 4 things, has which porous horizontal plate for which nerve and what extends superiorly from this plate?
Found between the orbits posteriorly.
Has:
-paranasal sinus
-upper portion of perpendicular plate
-superior nasal conchae
-middle nasal conchae
Cribiform plate has olfactory nerve pass through and crista galli extends superiorly.
Perpendicular plate of ethmoid bone makes up?
top 2/3 of nasal septum.
What is a suture?
An immovable joint between bones.
Which is the only bone in the cranium not joined by a suture?
Mandible.
Name all 4 sutures and what they join.
Sagittal- parietal bones.
Squamous- parietal and temporal bones.
Coronal- frontal and parietal bones.
Lambdoidal- parietal and occipital bones.
Where the sagittal and coronal suture meet is called?
Bregma
Bregma is
Where the sagittal and coronal suture meet.
Where the sagittal and lambdoidal suture meet is called?
Lambda
Lambda is
Where the sagittal and lambdoidal suture meet.
What is the weak point of the skull?
Pterion
Pterion is
Junction of parietal, temporal and sphenoid bones.
Junction of parietal, temporal and sphenoid bones is called?
Pterion
Asterion is
Junction of parietal, temporal and occipital bones.
Junction of parietal, temporal and occipital bones is called?
Asterion
