...
the apex is where the optic foramen is.
apex
area where the optic foramen transmits the optic nerve back into the sphenoid area
Frontal (orbital plate: goes back underneath the orbit), Zygoma, and Maxilla
the base of the orbit is formed by 3 bones. List them.
optic foramen
passageway for the optic nerve
sphenoid strut
the bony structure between the superior orbital fissure and the optic foramen
blood supply and nerves
the fissures are passageways for?
...
orbit series is done for pre-screening MRI to see if the patients have any metal shavings...if they were to be a welder...etc.
Tripod Fracture
when the zygoma breaks in 3 diff places. what type of fracture? Usually requires surgery to fix.
blow out fracture
a fracture that occurs in the floor of the orbit.
True
for the facial bone routine. it is important to include all of the facial bones and all of the mandible. True or False
True
If you were to clip the mandible on any views of the facial bone routine, it would be a repeat. True or False
True
For the Facial Bone Routine, you do not need the entire skull nor the vertex. True or False
...
for the waters method, we are trying to get the petrous ridges out of the face.
Maxillary Sinus
For the Waters Method, the PR should be below what sinus?
Air/fluid levels
if facial bone routine is done upright, it demonstrates what better?
centered to the zygoma
where do you want to center for the lateral?
80-85
kV used for the lateral facial bone?
affected
For the lateral facial bone routine, we want the (affected, unaffected) side down?
Outer Canthus and the EAM
For the lateral facial bone view, you want to center midway between which landmarks?
MML
For the waters projection, what line is perpendicular to the IR?
Acanthion
For the waters method, where does the central ray exit?
Parietoacanthial
The waters projection is AKA
37 degrees
IT IS IMPORTANT TO KNOW: the degree of difference between the OML and the IR is?
Blowout and Tripod
The waters method looks for what type of fractures?
orbit (especially the roofs)
The waters method is useful for fractures of the _____
75-85
kV used for waters method?
small
Do we use small or large focal spot for waters method?
You rest the chin
How is the chin positioned on the table/upright bucky device for the waters method?
OML
For the waters method, the _____ is 37 degrees with the IR
Petrous Ridges
For the waters method, what should be seen immediately below the maxillary sinuses?
are not
for the PA Waters, sometimes when the patient has trauma on the face, the maxillary sinuses (are/are not) well demonstrated because they may be fluid filled
isn't
In the PA waters, if the maxillary sinuses are aerated and appear dark, that means there (is/isn't) pathology
True
For the PA waters, if the maxillary sinuses are filled with mucous, blood, etc...they may not be well demonstrated...True or False
the distances between the oblique orbital lines and the lateral margin of the skull (even if the parietal eminences are NOT shown in its entirety)
For the PA waters method, what would you use to rule out rotation?
OML
In the Caldwell method, what line is perpendicular to the IR?
15 caudal
How many degrees do you use for the caldwell method?
nasion
For the Caldwell method, where does the central ray exit?
1/3
For the Caldwell method, the PR should be projected into the lower (1/2,1/3) of orbits
Waters method
the Modified waters is an alternative for the?
LML
Which line is perpendicular to the IR for the modified waters?
55
For the Modified Waters, how many degrees should be between the OML and the IR?
at the acanthion
For the Modified Waters, the central ray should exit where?
possible orbital fractures and foreign bodies in the eye
The modified waters should demonstrate what?
the floor of the orbits
The modified waters are useful to see what?
1/2
For the modified waters, the PR should be in the lower ___ of maxillary sinuses
need a higher technique and that means more patient dose and the led strips will show up on the image and will take away from recorded detail/resolution
what would be the disadvantage to using the grid (increases contrast and reduces scatter radiation) for the lateral nasal bone?
1/2 inch inferior to the nasion
Where do you center for the lateral nasal projection?
IPL
What line is perpendicular to the IR for the lateral nose bone?
zygomatic arches are relatively thin
why do we use a grid for the SMV Zygomatic Arches?
70-80
what kV is used for the SMV of the zygomatic arches?
1.5 inches distal to the mentum
where do you center for the SMV of the zygomatic arch?
True
For the SMV of the zygomatic arch...the grid is highly recommended. True or False
Parietal bone(the parietal bone will obscure the zygoma arch)
what happens if you don't tilt the head AWAY for the Oblique Inferosuperior (tangential) projection...what bone will get in the way?
to put the zygomatic arch with the long axis of the IR
why is the head rotated 15 degrees toward the affected side for the Tangential SMV of the zygomatic arch?
...
for the Oblique Inferosuperior (Tangential SMV), the head is rotated 15 degrees TOWARD the affected side and tilted 15 degrees AWAY from the affected side
depressed fractures of the arch
why is the Oblique Inferosuperior view used to demostrate?
SMV
Oblique Inferosuperior (Tangential)
AP Axial (Towne)
what is the basic routine for the zygomatic arch routine?
Parietoacanthial (Waters) and Lateral
What are the special projections for the zygomatic arches?
...
Stay Healthy! Wash your hands! :)