Skull Flashcards
Anatomy of the cranium
A: Parietal
B: glabella
C: sphenoid
D: superior orbital fissure
E: Temporal bone
F: Supraorbital foramen
G: optic foramen
H: Sphenoid bone
Anatomy
A: glabella
B: Pterion
C: Bregma
D: Coronal suture
E: Lambda
F: Lambdoidal suture
G: occipital bone
H: Ext. occipital protuberance (inion)
I: Asterion
J: EAM
K: Styloid process
L: frontal bone
M: Parietal bone
N: Squamosal suture
O: Sphenoid
P: Temporal
Q: Mastoid process
Cranial floor anatomy
A: Crista galli B: Cribreform plate C: Optic canal and foramen D: tuberculum sellae E: Ant. clinoid process F: Sella turcica G: Post. clinoid process H: Foramen lacerum I: Dorsum sellae J: Jugular foramen K: Hypoglossal canal L: Foramen magnum M: Occipital N: Clivus O: Petrous portion P: Diploe Q: Temporal bone R: Foramen spinosum S: Foramen ovale T: Optic groove U: Greater wing V: Lesser wing W: Orbital plate X: Anterior Y: Middle Z: Posterior
Slice of lateral skull anatomy
A: Maxilla B: Vomer C: Ethmoid D: Nasal E: Crista galli F: frontal sinus G: Frontal H: diploe I: Parietal J: Sphenoidal sinus K: Squamous portion of temporal L: Internal acoustic meatus M: Occipital bone N: Petrous portion of temporal bone O: Clivus P: Pterigoid hamulus Q: Palatine bone
Fontanels
A: Anterior fontanel
B: Posterior (lambda) fontanel
C: Mastoidal fontanel
D: Sphenoidal fontanel
Frontal surface anatomy
A: Frontal squama
B: Supraorbital margin
C: Glabella
D: Nasal spine
E: Superciliary arch
F: Frontal eminence
G: Superorbital foramen
H: Nasion
Ethmoid anatomy
A: Superior nasal conche
B: middle nasal conche
C: perpendicular plate
D: Crista galli
E: ethmoidal sinus
F: Medial orbital wall
G: Air cells in Labyrinth
Ethmoid anatomy
A: sphenoid
B: vomer
C: Cribriform plate
D: Crista galli
E: frontal
F: nasal
G: cartilage of nasal septum
H: perpendicular plate
What bone and its articulations?
Parietal (ext) bone
A: Parietal
B: occipital
C: temporal
D: frontal
Name the angles
A: Occipital
B: Mastoid
C: Frontal
D: sphenoid
Sphenoid anatomy
A: Lesser wing B: Optic groove C: Greater wing
D: Optic canal E: Foramen ovale F: Foramen spinosum
G: carotid sulcus H: Dorsum sellae I: Sella turcica
J: Posterior clinoid process K: Tuburculum sellae
L: Foramen rotundum M: Anterior clinoid process
Occipital
A: Squama
B: External occipital protuberance (inion)
C: Foramen magnum
D: occipital condyle
E: Basilar portion
F: Condylar canal
internal occipital
A: Fossa for cerebrum
B: Internal occipital protuberance
C: Fossa for cerebellum
D: Hypoglossal canal
E: Foramen magnum
F: Jugular process
G: Condyle for articulation with atlas
H; Basalar portion
What bone is this and its parts?
Temporal bone
A: Mastoid portion
B: EAM
C: Mastoid process
D: Tympanic portion
E: Styloid process
F: Mandibular fossa
G: Articular tubercle
H: zygomatic process
I: Squamous portion
What is this bone and its parts?
Temporal bone
A: Mastoid process
B: Mastoid air cells
C: Squamous portion
D: Mastoid antrum
E: Arcuate eminence
F: Semicircular canal
G: Petrous ridge
H: petrous apex
I: Carotid canal
J: Promontory (formed by cochlear base)
Name the 9 anterior landmarks pg 286
1: angle of mandible or gonion
2: infraorbital margin
3: outer canthus
4: glabella
5: interpupillary line
6: inner canthus
7: nasion
8: acanthion
9: mental point
Name the 9 lateral landmarks
1: Gonion
2: EAM
3: Auricle
4: Top of ear attachment
5: Glabellomeatal line
6: orbitomeatal line
7: infraorbitomeatal line
8: Acanthiomeatal line
9: Mentomeatal line
Name the 3 different skull shapes
1: mesocephalic skull
2: brachycephalic skull
3: Dolichocephalic skull
Which is the typical skull size/shape?
mesocephalic
What skull is short from front to back and wide from side to side?
Brachycephalic
What skull is long from front to back and narrow from side to side?
dolichocephalic
When imaging the skull in an adult what is the best radiation protection?
Collimation but always shield the groin for patient reassurance.
Pt position for Lateral cranium?
seated upright or semiprone on table
for the lateral skull how is the MSP to the plane of the IR?
parallel
for the lateral skull, what is the position of the IOML to the front edge of the IR? And for the long axis of the IR?
perpendicular
for the lateral skull the interpupillary line should be _______
perpendicular
For lateral skull, where should the central ray enter the anatomy?
2” superior to the EAM
What is the colilmation for a lateral skull?
10x12
What are some important landmarks to look for when evaluating a lateral skull radiograph?
everything is superimposed and the sella turcica is in profile
How would you do a trauma lateral skull?
Cross table with a horizontal beam
What is another name for the PA or PA axial skull?
Caldwell
What is the patient position for the Caldwell?
either prone or seated with forehead and nose resting on table or bucky. If prone, flex elbows
With a Caldwell skull what landmark should be perpendicular to the plane of the IR?
OML
For the Caldwell skull how should the MSP be positioned with the IR?
perpendicular
For the caldwell skull where should you center the IR?
To the nasion
For the PA projection when the frontal bone is primary interest, where should you direct the CR?
Perpendicular to exit the nasion
for the caldwell, how should the CR be directed?
to exit the nasion at a 15 degree angle caudad
For the Caldwell skull how should the MSP be positioned with the IR?
perpendicular
For the caldwell skull where should you center the IR?
to the nasion
For the PA projection when the frontal bone is primary interest, where should you direct the CR?
Perpendicular to exit the nasion
To visualize the superior orbital fissures for the PA skull, where should the CR be directed?
through the mid orbits at a 20-25 degree angle caudad
To visualize the rotundum foramina in a PA skull, where should the CR be directed?
to the nasion at a 25-30 degree angle caudad
What is the collimation for the PA & Caldwell skull?
10x12
For a PA skull with a straight beam, how are the petrous pyramids situated in the image?
they fill the orbits
When doing a 15 degree caudad angle for the Caldwell PA skull, where are the petrous pyramids situated in the image?
into the lower 1/3 of the orbits
When doing a 30 degree Caldwell PA skull, where are the petrous pyramids situated in the image?
Well below the orbits
When would it be ok to move the patients head into a true lateral position for a PA skull?
During a trauma after the spinal injury has been ruled out.
What is the main criteria to look for in a PA skull image?
Petrous pyramid relationship with orbits, equal distance from lateral border of orbit to both sides…and nothing is cut off!
What is the pt position for the AP skull?
Supine or seated upright
Where is the CR to be directed for the AP skull?
oward the nasion straight or if doing a AP axial (not recommended) at 15 degrees cephalad
When is a AP or AP axial skull usually done?
When the pt cannot position for the PA or PA axial.
What is the collimation for the AP skull?
10 x 12
What is shown in an AP image?
The same criteria as the PA only the orbits are magnified do to OID
The more common AP axial projection is also called…
Towne method
(think DOWNTOWN)
what is the pt position for the Town (AP axial) method?
supine or seated
What is the position of the MSP for the Towne projection?
perpendicular
What is the landmark for the Town projection and what is its position?
the OML should be perpendicular to the plane of the IR
If the pt cannot flex enough for the OML to be perpendicular to the IR, what is the alternative?
the IOML can be perpendicular (degree of the CR must also be increased by 7 degrees)
Where is the upper margin of the IR when positioning for the Town projection?
at the level of the highest point of the cranial vertex
Where is the CR directed for the Town (AP axial) projection and how many degrees?
through the foramen magnum at a 30 degree caudal angle unless the IOML is perpendicular then the angle changes to 37 degrees caudal
Where is the CR to enter when doing the Town (AP axial) projection?
2.5” above the glabella and passes through the level of the EAM
What is shown in the images for the Towne projection?
symmetric petrous pyramids, posterior foramen magnum, the posterior clinoid is within the foramen magnum
For the Town (AP axial) projection, what needs to be done to see the entire foramen magnum?
increase the caudal angle to 40-60 degrees to the OML
What is a main reason to do a PA axial (HAAS method) on a patient?
When the pt is to obese or cannot sit correctly for the AP axial (Towne) projection.
How is the pt positioned for the PA axial (HAAS) projection?
prone or seated upright; if prone flex elbows for support.
How is the part positioned for the PA axial skull (HAAS) projection?
forehead and nose on the table with the MSP perpendicular to the grid
What is the landmark and how is it situated for the PA axial skull (HAAS) method?
the OML is perpendicular to the IR
How is the CR directed for the PA axial skull (HAAS) projection?
25 degrees to the OML cephalad
Where does the CR enter for the PA axial skull (HAAS) projection?
1.5” below the external occipital protuberance (inion) and exits about 1.5” superior to the nasion
What is shown for the PA axial (Haas) skull image?
he occipital region, petrous pyramids, dorsum sellae & posterior clinoid process within the foramen magnum
What is also known as the reverse town method?
the PA axial skull or (HAAS method)
What does SMV stand for?
Submentovertical
What is another name for the SMV projection?
the schuller method
What is the landmark for the SMV and how should it be positioned?
the IOML should be as nearly parallel with the plane of the IR as possible
How is the CR in relation to the IOML for the SMV skull method?
perpendicular to the IOML
For the SMV projection of the skull, what is the ideal position in which to place the pt?
Ideal position to place the pt is sitting upright in a chair. If unable for pt to be in this position, images can be obtained with pt supine. Midsagittal plane perpendicular to IR.
If the pt has to be supine for the SMV skull what additional steps should be taken?
elevate the torso on firm pillows to allow the head to rest on its vertex, hyperextending the neck
How should the CR be directed for the SMV projection? (Schuller method)
perpendicular to the IOML, entering the throat between the angles of the mandible, passing through a point 3/4” anerior to the level of the EAM
The CR should be centered to the ____ and the IR should be parallel to the _____ for the SMV
IR
IOML
What is seen on the SMV image for the skull?
Just about everything! maxillary sinus, ethmoid air cells, sphenoid sinus, mandible, foramen spinosum, mandibular condyle, dens, petrosa, mastoid process, occipital bone
(TEETH ARE SUPERIOR IN THE IMAGE & OCCIPITAL IS INFERIOR)
What are the 4 typical set of projections for a skull series?
1 & 2. both laterals
- PA axial (caldwell)
- AP axial (Towne method)
What is the degree difference between the OML and IOML?
7 degrees
What is the degree difference between the OML and the GML?
8 degrees
What is the degree difference between the GML and the IOML?
15 degrees
What views show the rotundum foramina?
Modified Caldwell with a 25-30 degree angle, exit nasion
&
Waters
Anatomy of the cranium
A: Parietal
B: glabella
C: sphenoid
D: superior orbital fissure
E: Temporal bone
F: Supraorbital foramen
G: optic foramen
H: Sphenoid bone
