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
which specific facial bone structures (other than the mandible) are best demonstrated with the SMV projection if the correct exposure factors are used (soft tissue technique)?
zygomatic arches
where is the CR centered for an AP axial projection for the zygomatic arches?
1 inch superior to the nasion
list the proper method name and the common descriptive name for the parieto-orbital oblique projection for the optic foramen
- Rhese method
- three point landing
the three aspects of the face that should be in contact with the head unit or tabletop when beginning positioning for the parieto-orbital oblique projection are the (a)____, _____, and ___. The final angle between the midsagittal plane and the IR should be (B)_____, with the(C) ____ line perpendicular to the IR. The places the optic foramen in the (D)______ quadrant of the orbit
a - cheek, nose, chin
b - 53 degrees
c - AML
d - lower outer
what projection best demonstrates the floor of orbits (blowout fractures)?
modified waters method
what projection best demonstrates the optci foramen?
parieto-orbital oblique projection
what projection best demonstrates the view of a single zygomatic arch?
oblique inferosuperior projection
what projection best demonstrates the profile image of nasal bone and nasal septum?
lateral (nasal bone)
what projection best demonstrates the bilateral zygomatic arches?
SMV projection
what projection best demonstrates the inferior orbital rim, maxillae, nasal septum, nasal spine, zygomatic bone, and arches?
parietoacanthial projection
true or false: the PA axial projection of the mandible produces an elongated view of the condyloid process
true
which projection of the mandible projects the opposite half of the mandible away from the side of interest?
axiolateral oblique
what must be done to prevent the ramus of the mandible from being superimposed over the cervical spine with an axiolateral oblique projection of the mandible?
extend the chin
what specific positioning error has been committed if both sides of the mandible are superimposed with an axiolateral projection?
- insufficient cephalic CR angle
- skull tilt
where should the CR exit for a PA axial projection of the mandible?
acanthion
which cranial positioning line is placed perpendicular to the IR for a PA or PA axial projection of the mandible?
OML
true or false: for a true PA projection of the mandible body, the AML should be perpendicular to the IR
true
true or false: the CR should be angled 20-25 degrees caudad for the PA axial projection of the mandible
false
which aspect of the mandible is best visualized with an AP axial projection?
condyloid process
what KVP range should be used for paranasal sinus radiography?
75-85 kVp
to demonstrate any possible air or fluid levels within the paranasal sinus, it is important to:
- perform erect position
- use horizontal beam
true or false: ultrasound exams of the maxillary sinuses rule out sinusitis are possible?
true
true or false: MRI is the preferred modality to study soft tissue changes and masses within the paranasal sinuses
true
true or false: secondary osteomyelitis is often caused by a tumor invasion
false
list the 4 commonly performed routine projections for paranasal sinuses
- lateral
- PA caldwell
- SMV
- waters method
which single projection for a paranasal sinus routine provides an image if all 4 sinus groups?
lateral
if the patient cannot stand for the lateral projection of the paranasal sinuses, the projection should be taken with -
horizontal x-ray beam
which paranasal sinuses are best demonstrated with a PA (caldwell) projection?
frontal and anterior ethmoid
to avoid angling the CR for the erect PA (axial) caldwell sinus projection, the head should be adjusted so that the OML is _____ degrees from horizontal?
15
which group of paranasal sinuses is bets demonstrated with a waters projection?
maxillary sinuses
the OML forms a ___ degree angle with the IR with a waters projection
37
which positioning line is placed perpendicular to the IR for a waters projection?
MML
where are the petrous ridges located on a well positioned waters method?
below the maxillary sinuses
which paranasal sinuses are demonstrated with an SMV projection of the paranasal sinuses?
sphenoid, ethmoid, and maxillary sinuses
where should the CR exit for both the PA waters and the PA transoral )open mouth waters) projection?
acanthion
what is one major difference in positioning between the waters and open mouth waters projection?
with PA open mouth, the mouth is open
which paranasal sinuses are projected through the oral cavity with the PA axial transoral projection?
sphenoid sinus
