Skull Anatomy Flashcards
How many bones is the skull composed of ?
22
how many groups is the skull divided into?
2 groups
What are the two groups that the bones of the skull are divided into?
Cranial bones
Facial Bones
How many cranial bones are there
8
how many facial bones are there ?
14
cranial bones are further subdivided into :
Calvaria and Floor
What is the inner layer of spongy bone separating two outer plates of compact tissue
-composition of calvarium bones
Diploe
cranial Bones of the calvaria
Frontal
Occipital
Right parietal
Left parietal
Cranial bones of the floor
Ethmoid
Sphenoid
Right temporal
Left temporal
The cranial floor is divided into three regions
-anterior cranial fossa
-middle cranial fossa
-posterior cranial fossa
houses frontal lobes of cerebrum; extends from anterior frontal bone to lesser wings of sphenoid
Anterior cranial fossa
houses temporal lobes; extends from lesser wings of sphenoid to apices of petrous ridges
Middle cranial fossa
deep depression posterior to petrous ridges; protects cerebellum, pons, and medulla oblongata
Posterior cranial fossa
fibrous joints that connect the bones of the skull
Sutures
what suture is between frontal and parietal bones
coronal
what suture is on top of head between two parietal bones
sagittal
what suture is between temporal bone and parietal bones
squamosal
what suture is between occipital and parietal bones
lambdoidal
junction of coronal and sagittal sutures
Bregma
junction of sagittal and lambdoidal sutures
Lambda
areas of incomplete ossification in infant skulls (i.e., “soft spots”)
Fontanels
what age is the adult cranial size usually achieved
age 12
once was the sphenoidal fontanel
Pterion
once was the mastoid fontanel
Asterion
The inner layer of spongy tissue found inside cranial bones is called :
Diploe
The fontanel located at the junction of the coronal and sagittal sutures is the
Bregma
or foramina
The two parietal bones articulate with the frontal bone to form what suture ?
Coronal
The cranial bone that provides a depression to house the pituitary gland is what bone
sphenoid
The fontanel located at the junction of the lamboidal and sagittal sutures is the ?
Lambda
The bone that forms the anterior portion of the cranium is what bone
Frontal
The cranial bone located between the orbits and posterior to the nasal bones is what bone
Ethmoid
The two parietal bones and the occipital bone joint together to form what suture
Lambdoidal
The anterior clinoid process is located on what bone
Sphenoid
Which bone contains the transmission of the olfactory nerves
Ethmoid
bones that are at the top of the skull
cranial
bones of the skull that are in the front
Facial bones
what is the plane that is front to back
coronal
what is the plane that is up and down
axial
what is the plane that is left and right
sagital
very top of the head
Bregma
what does the posterior fontanel become
the lambda
what does the frontal fontanel become
Bregma
what bone Has vertical portion (frontal squama) and horizontal portions
Frontal bone
what does the frontal squama form
Frontal squama forms forehead and anterior part of cranial vault
what does the horizontal portion of the frontal bone form?
Horizontal portions form orbital plates, part of roof of nasal cavity, and greater part of anterior cranial fossa
landmarks of the frontal bone :
Frontal eminences
Supraorbital margins
Supraciliary arches
Supraorbital foramina
Glabella
what bone Articulates with right and left parietals, sphenoid, ethmoid, nasal bones, and zygoma
Frontal bone
what fits in the ethmoidal notch ?
ethmoid
what does the ethmoid consist of :
Consists of
Horizontal plate
Vertical plate
Two light, spongy masses = labyrinths
what bone is Located between the orbits and forms part of anterior cranial fossa, nasal cavity, orbital walls, and bony nasal septum
Ethmoid bone
what is the horizontal portion of the ethmoid bone called?
cribriform plate
what part of the ethmoid bone is this: conical projection at anterior midline of cribriform plate
Crista galli
what part of the ethmoid is : vertical portion; forms superior portion of bony nasal septum
Perpendicular plate =
what part of the ethmoid bone contains numerous foramina for transmission of olfactory nerves
Cribriform plate
what part of the ethmoid bone is this:
Contain ethmoid sinuses or air cells
Walls form part of medial walls of orbits and lateral walls of nasal cavity
Have two thin, scroll-shaped projections = superior and middle nasal conchae
Labyrinths
what bone Articulates with frontal, sphenoid, lacrimal, maxilla, and vomer
Ethmoid bone
what part of the ethmoid bone will meet up with the vomer and make up the nasal septum
Perp. plate
what part of the parietal bone is this: prominent bulge near center of external surface of each bone
This is the point where the width of the skull should be measured to set technique
pariteal eminence
Somewhat square
Have a convex external surface and concave internal surface
Parietal Bones
what does the parietal bones articulate with
Articulate with:
each other at the sagittal suture in MSP, the frontal,
temporal,
occipital,
and sphenoid bones
Irregular, wedge-shaped bone that vaguely resembles a bat
sphenoid bone
Located in base of cranium anterior to temporal bones and basilar portion of occipital
sphenoid
what does the sphenoid consist of :
Body
Two lesser wings
Two greater wings
Two pterygoid processes
sella turcica
clivus
optical canal
dorsum sellae
posterior clinoid processes
Body contains two sphenoid sinuses and forms posterior bony wall of nasal cavity
Sphenoid bone
what part of the sphenoid is this:
deep depression on superior surface of body
sella turcica
what part of the sphenoid is this:
Houses pituitary gland
Located in MSP of cranium ¾ inch (1.9 cm) anterior and superior to external acoustic meatus (EAM)
sella turcica
names parts of the ethmoid bone :
labyrinths, cribiform plate, crista galli, perp plate
names parts of the parietal bone:
parietal eminence,
what part of the sphenoid is this: anterior border of sella
Tuberculum sellae
what part of the sphenoid is this: posterior border of sella
Dorsum sellae
what part of the sphenoid is this:
top borders of dorsum
Posterior clinoid processes
what part of the sphenoid bone is this:
slanted area of bone posterior and inferior to dorsum
Continuous with basilar area of occipital
Supports pons of the brain
Clivus
what part of the sphenoid bone is this:
opening into the apex of orbit for transmission of optic nerve and ophthalmic artery
Actual opening is termed optic foramen
optic canal
what wings of the sphenoid bone arise from anterior and superior portion of body and lie horizontally on each side
lesser wings
what part of the sphenoid bone Form posteromedial portion of orbital roofs, posterior portion of anterior cranial fossa, upper margin of superior orbital fissure, and optic canals
Medial ends form the anterior clinoid processes
lesser wings
what part of the sphenoid :
arise from sides of body and curve laterally, posteriorly, anteriorly, and superiorly
Form part of middle cranial fossa and posterolateral walls of orbit
greater wings
what part of the sphenoid bone arise from lateral portions of inferior surface of body and medial portions of inferior surfaces of greater wings
Pterygoid processes
which three paired foramina situated on greater wings
Rotundum
Ovale
Spinosum
what bone is Situated at posteroinferior part of cranium
Occipital bone
what bone Forms posterior half of cranial base and greater portion of posterior cranial fossa
Occipital bone
what are the four parts of the occipital bone
Squama
Two occipital condyles
Basilar portion
what part of the occipital bone has a = large opening through which medulla oblongata passes as it exits cranium
foramen magnum
what part of the occipital bone has a prominent process on squama
Also called inion
Corresponds to internal occipital protuberance
External occipital protuberance
what bone is Situated on each side of cranial base between greater wings of sphenoid and occipital bone
temporal bone
what bone Form large part of middle cranial fossa and a small part of posterior cranial fossa
temporal bone
what is the temporal bone consists of :
-Squamous portion
-Tympanic portion
-Styloid process
-Zygomatic process
-Petromastoid portion, which contains the organs for hearing and equilibrium
what part of the temporal bone is this:
= thin, upper portion of temporal bone
Forms part of side wall of cranium
temporal bone
what part of the temporal bone is this:
prominent arched process that projects anteriorly to articulate with zygoma and complete the zygomatic arch
Zygomatic process
what receives condyle of mandible to form temporomandibular joint (TMJ)
Mandibular fossa
what part of the temporal bone is this:
located below squama and in front of petromastoid portion
Forms anterior wall, inferior wall, and part of posterior walls of the EAM
Tympanic Portion
what part of the temporal bone is this: slender, pointed bone projecting inferiorly, anteriorly, and slightly medially from inferior surface of tympanic portion
styloid process
how is the sella turcica located
located in the MSP of cranium 3/4 inch anterior and superior to external acoustic meatus (EAM)
what projects medially and anteriorly between greater wing of sphenoid and occipital bone
Petrous portion
Conical or pyramidal in shape
Thickest and densest portion of cranium
Contains the organs of hearing and balance
petrous pyramid or petrous portion
conical process projecting from mastoid portion
mastoid process
bones of middle ear
Malleus
Incus
Stapes
Auditory ossicles
what does the temporal bone articulate with
the parietal, occipital, sphenoid, zygoma, and mandible
Three canals at right angles
semicircular canals
what view is to see optic canal
reese view
-sensory organ of ampulla
-hair cells and supporting cells
-rapid turns of head or body stimulate hair cells
semicircular canals
swelling of membranous labyrinth that communicates with the vestibule
semicircular canals
what is the thickest part of the skull ?
petromastoid portion
contains organs for hearing
temporal
what does the condyle of mandible fit into
the mandibular fossa
which cranial bones are paired?
temporal
the sella turcica is part of the :
sphenoid bone
which of the following bones are part of the cranial floor ?
1. ethmoid
2. frontal
3. temporal
1 and 3
