Chapter 11 workbook - paranasal sinus and mandible Flashcards
true or false: facial bones should always be performed recumbent whenever possible
false
true or false: the common basic PA axial projection for facial bones require 15 degree caudad angle of the central ray, which projects the dense petrous ridges into the lower one-third of the orbits
true
true or false: an increase in kVp of 25% to 30% (unsing manual techniques) is often required for the geriatric patient with advanced osteoporosis
false
true or false: CT is ideal for facial bone studied because it allows for the visualization of bony structures as well as related soft tissues of the facial bones
true
true or false: nuclear medicine is not helpful in diagnosing occult facial bone fractures
false
true or false: MRI is an excellent imaging modality for the detection of small metal foreign bodies in the eye
false
what is the name of the fracture that results from a direct blow to the orbit leading to a disruption of the inferior orbital margin?
blowout fracture
a “free-floating” zygomatic bone is the frequent result of a ___ fracture
tripod
what is the major disadvantage of performing a straight PA projection for facial bones, with no CR angulation or neck extension, as compared with other PA facial bone projection?
petrous pyramids superimposed on orbits, obscuring facial structures
where is the CR centered for a lateral position for the facial bone?
a. outer canthus
b. acanthion
c. zygoma
d. nasion
c. zygoma
what is the proper method name for the parietoacanthial projection of the facial bone?
waters view
which facial bone structures are best seen with a parietoacanthial projection?
- infraorbital rims
- bony nasal septum
- maxillae
- zygomatic bone/arches
what CR angle must be used to protect the petrous ridges just below the orbital floor with the PA axial (caldwell method) projection?
a. none. CR is perpendicular
b. 30 degrees
c. 20 degrees
d. 45 degrees
b. 30 degrees
which structures specifically are better visualized on the modified parietoacanthial (waters) projection as compared with the basic Waters projection?
orbital rims and orbital floors
gives 2 reasons why projections of the facial bones are performed PA rather than an AP when possible?
- reduces OID
- reduces exposure to anterior facial bones
what are the 2 differences between the lateral projection of the cranium and the lateral projection for the facial bones?
facial CR: Zygoma
Cranium CR: 2 inches superior to EAM
facial IR: portrait
Cranium CR: lanscape
the parietoacanthial (waters) projection for the facial bones has the ___ line perpendicular to the IR, which places the OML at a ___ degree angle to the tabletop of the IR
MML; 37
where does the CR exit for a parietoacanthial (waters) projection of the facial bones?
acanthion
where does the CR exit for a 15 degree PA axial (caldwell) projection for the facial bones?
nasion
the modified parietoacanthial (modified waters) projection requires that the ____ line is perpendicular to the IR, which places the OML at a ___ degree angle to the tabletop and IR
LML; 55 degree
true or false: Lateral projections for nasal bones generally are taken bilaterally for comparison
true
true or false: the oblique inferosuperior (tangential) projection for the zygomatic arch requires that the skull be rotated and tilted 15 degrees away from the affected side?
false
true or false: both oblique inferosuperior (tangential) projections for the zygomatic arch are generally taken for comparison
true
for parietoacanthial (PA Waters) projection, the petrous ridges should be projected directly below the ___ and projected into the lower half of the maxillary sinuses or below the ___ for the modified waters projection
maxillary sinuses; inferior orbital rims
for the superoinferior projection of the nasal bones, the IR is placed perpendicular to the _____ line
GAL - glabeloalveolar line