Skull Flashcards
How many cranial bones are there and name them.
8 cranial bones Frontal Parietal ( rt and left) Occipital Temporal (rt and left) Sphenoid Ethmoid
The skullcap or top of the skull is also termed?
Calvarium
The calvarium (skullcap) is consisted of how many of the cranial bones and which of them make up the calvarium
4 bones of the Top (Top= FOP)
Frontal
Occipital
Rt and left Parietal
How many of the cranial bones makes up the floor of the skull and which ones are they
Floor of skull (TEST)
Rt Temporal
Ethmoid
Sphenoid
Left temporal
Which cranial bone brings/articulates with all of the cranial bones
Sphenoid
Which part of the frontal bone forms the forehead
Squamous/ vertical portion
Which part of the frontal bone forms the superior part of the orbits
Orbital/ horizon portion
What is the glabella
Smooth, raised prominence just above the ridge of the nose
Supraorbital groove (SOG)
Slight depression above each eyebrow
Supraorbital margin (SOM)
Superior margin/ rim of each orbital
Superciliary ridge/ arch
Bone between eyebrow and the SOM (supraorbital margin)
Frontal bone articulations
Frontal bone articulate with 4 cranial bones: rt. and left parietal, sphenoid and ethmoid
Widest portion of the skull?
Widest portion is located between the 2 parietal tubercles (or eminence) of the 2 parietal bones
Articulations of the parietal bones
Each parietal bone articulates with 5 cranial bones: frontal occipital, temporal, sphenoid and the opposite parietal bone.
What is the external occipital protuberance ( aka inion)
Prominent bump at the inferoposterior portion of skull. It is the point for muscle attachment
What is the foramen magnum
Large opening at the base of the occipital theories which the spinal cord passes through. It literally means “great hole”
What is found on the sides of the foramen magnum?
On each side of the foramen magnum are the lateral occipital condyles. These articulates with the depression on the first cervical vertebra ( the atlas) this articulation of the skull and cspine forms the atlanto-occipital joint.
Articulations of the occipital bone
Occipital bone articulate with 6 bones: rt and left parietal, rt and left temporal, sphenoid and the atlas ( the first cervical vertebra)
Which cranial bone houses the delicate organ of hearing and balance
The rt and left temporal bone
The temporal bone is divided into 3 primary parts. What are they.
First: squamous portion. Thin and is the most vulnerable portion of the entire skull to fracture.
Second: mastoid portion. Many air cells are housed here
Third: petrous portion (aka petrous pyramid or pars petrosa) it houses the organ of hearing and equilibrium, including the mastoid air cells
Where is the location of the petrous ridge?
The petrous ridge, aka petrous apex, is located at the upper border or ridge of the petrous pyramid.
True or false: the petrous pyramid is the thickest and densest bone in the cranium.
True
The petrous ridge corresponds to what level
Petrous ridge corresponds to the level of TEA (Top Ear Attachment)
What does the sella turcica look like on the sphenoid bone
The central depression on the body of the sphenoid.
What does the sella turcica partially surrounds and protect?
Sella turcica protects the pituitary gland.
There are three pairs of small openings that exist in the greater wings of the sphenoid. What are they and what do they serves as
The three small foramina: ROS Rotundum Ovale Spinosum They serves as passage for cranial nerves.
Where is the connection point for nerves in the sphenoid bone?
Connection point for nerves begins at the chiasmatic (optic) groove. These nerves then leads to the optic canal and finally to the optic foramen, an opening to the orbits.
Small “hook” like process on the sphenoid bone
Pterygoid hamuli
Medial and lateral to the pterygoid hamuli (“hooks”) is what? And what Do they form?
The medial and lateral pterygoid process (“legs”). They form part of the lateral wall of the nasal cavity.
The cribiform plate of the ethmoid bone contains what?
Small branches of olfactory nerves ( smell)
Located superiorly of the cribiform plate is the crista Galli. This portion touches what,
Crista Galli touches the brain
The lateral labyrinth masses of the ethmoid bones contains what and what cavity does it lies within?
The lateral labyrinth masses contains air cells or sinuses and it
It’s within the nasal cavity.
Within the lateral labyrinth masses are small projections. What are they called.
They are superior and middle nasal concha.
Articulation of the ethmoid bone
Articulates with 2 cranial bone: frontal and sphenoid
The articulations or joints of the cranial bones are termed?
Sutures.
Joint classification of the sutures
The sutures are fibrous and in adults they are synarthrodial (immovable)
What is the only moveable joint in the cranium?
Only moveable joint is the TMJ (temporomandibular joint)
True or false: the calvarium of an infant is very large in proportion to the rest of the body
True
“Soft spots” on an infants skull is termed
Anterior and posterior fontanels
The anterior fontanel is the largest at birth and does not fully closed until what age
Roughly 18 months of age
What are the four sutures of the skull ( they’re the same in infant and adults)
Coronal suture
Saginaw suture
Squamosal suture
Lamdoidal suture
Sutural, or Wormian, bones are also termed what
Also termed “island of bones”. They are small, irregular, isolated bones that sometimes form in the adult skull
What structures are found in the petrous portion of the temporal bones
The organs of hearing and equilibrium are the main structures found
The opening or canal of the external ear is termed what
EAM ( External Acoustic Meatus)
The middle ear contains what
Tympanic membrane
3 auditory ossicles ( malleus “hammer”, incus “anvil”, stapes)
Tympanic cavity
What is the Eustachian tube
Passageway between middle ear and the nasopharyx. It leads to the throat and serves to equalize the pressure of the middle ear to the outside atmospheric pressure.
The three auditory ossicles of the middle ear (malleus, incus, stapes) purpose?
These three bones transmit sound vibrations from the tympanic membrane to the oval window of the inner ear.
Depression fracture of the skull is also called ?
Ping pong fracture
Paget’s disease gives up what kind of an approach
Colton wool appearance
What are the 3 skull morphology
Mesocephalic ( stenic; avg. )
Brachycephalic ( wide side to side)
Dolichocephalic (long front to back)
Rotation of the head dis determined by what line
MSP (mid Sagital plane)
Tilt is determined by what line
IP Line (InterPupillary line)
Reid’s base line is an older term that describe what
Neutral position of the head
Skull series contains what views
Townes: (depress chin, OML perpendicular to IR, 30 caudad, CR to 2.5” above glabella)
Lateral: (side of interest to IR, IPL perp.,IOML perp. to front edge of IR, CR to 2” above EAM)
Caldwell: (PA, OML perp to IR, CR 15 caudad to exit at nasion)
PA : (normal PA. No angle, OML perp to IR, center to exit at glabella
AP or PA will magnified the orbital?
AP will magnify the orbital
A TRUE PA Caldwell will demonstrate what?
A TRUE PA Caldwell will show the petrous ridges at the lower 1/3 of the orbits
Where are the petrous ridges on a normal, no angle PA?
At the very top of the orbits.
Can you visualize the roof of the orbits in a normal, no angle PA?
No
Can you visualize the roof of the orbits in a PA Caldwell?
Yes
kVp for skull
80-85 in all views
SID for skull
40”
Describe SMV view
Hyperextension of neck until IOML is parallel to IR, and CR to 1.5” below mandibular symphysis
