Cranial Positioning Flashcards
1
Q
What does AML stand for? Location?
A
Acanthiomeatal line / connects the acanthion to the EAM
2
Q
What does LML stand for? Location?
A
Lips- meatal line / connects the junction of the lips to the EAM
3
Q
What does MML stand for? Location?
A
mentomeatal line / connects the mental point (chin) to the EAM
4
Q
What does GML stand for? Location?
A
glabellomeatal line / connects the glabella to the EAM
5
Q
What does OML stand for? Location?
A
orbitomeatal line / connects the outer canthus of the eye to the EAM
6
Q
What does IOML stand for? Location?
A
infraorbitomeatal line / connects a line below the eye to the EAM
7
Q
What does GAL stand for? Location?
A
glabelloalveolar line / connects the glabella to a point at the anterior aspect of the alveolar process of the maxilla
8
Q
Describe the relationship between the infraorbitomeatal line (IOML) and the orbitomeatal line (OML)
A
an average difference of 7° between the angles
9
Q
How can you tell if there is rotation on a lateral position of the skull?
A
anterior and posterior separation of symmetric vertical bilateral structures such as the EAM, mandibular rami, and great wings of the sphenoid
10
Q
What is the significance of the difference between the IOML and OML?
A
If a patient is unable to flex the neck enough to line up the OML, a line from the IOML can be used. HOWEVER, you MUST add 7° to your CR angle. (SO 30 for OML and 37 for IOML)
11
Q
What could be demonstrated on a horizontal beam lateral of the skull that would not be on a lateral view taken with routine positioning?
A
air-fluid levels
12
Q
Which projection best demonstrates a blowout fracture?
A
Modified parietoacanthial Projection of the Facial Bones (Modified Waters Method)
13
Q
How can one determine on an image if a patient is properly positioned for the Water’s projection?
A
Petrous ridges just inferior to the maxillary sinuses
14
Q
how can rotation be detected on an image of the Water’s projection?
A
equal distance from the midlateral orbital margin to the lateral cortex of cranium on each side
15
Q
For the Water’s projection, the MML should be perpendicular to the IR. Describe the relationship between the OML and the plane of the IR.
A
The OML and the IR plane will form a 37° angle
16
Q
list the differences between the Water’s and Modified Water’s projections.
A
Waters - MML perp to IR, OML forms 37° angle, and chin against table
Modified waters - LML is perp to IR, OML forms a 55° angle, chin and nose against table
17
Q
If the chin was not extended for the axiolateral projection of the mandible, what outcome would be visualized on the finished radiograph?
A
The cervical spine and the ramus will be superimposed
18
Q
Why should a paranasal sinus series always be done erect?
A
to visualize air-fluid levels
19
Q
A TMJ series generally includes ____ and ___ mouth projections.
A
open and closed
20
Q
Where is the CR located and directed on an Axiolateral oblique projection of the TMJ (Modified Law Method)
A
Angle CR 15° caudad and center to 1 1/2 inches superior to upside EAM (to pass thru downside TMJ)
21
Q
Where is the CR located and directed on an Axiolateral projection of the TMJ (Schuller Method)?
A
Angle CR 25° caudad and center to 1/2 inch anterior and 2 inches superior to upside EAM
22
Q
In a trauma situation a TMJ series should only be performed after a radiographic exam of the _____. Why?
A
mandible; Because the mouth should not be opened if a fracture is present
23
Q
Sometimes with certain facial/skull fractures blood and/or fluid accumulation may be seen within a paranasal sinus. Which specific sinuses would we expect to see filled with blood or fluid for:
- Blowout fracture -
- Basilar skull fracture -
A
- Maxillary sinuses
- Sphenoid sinuses
24
Q
For the AP Axial Projection (Towne Method) of the skull what is the CR location?
A
2 1/2 inches above the glabella to pass thru the foramen magnum
25
For the AP Axial Projection (Towne Method) of the skull what is the CR angulation?
30° caudad for OML, 37° caudad for IOML (If pt can't depress chin enough use IOML)
26
For the AP Axial Projection (Towne Method) what is the anatomy demonstrated?
occipital bone, petrous pyramids and foramen magnum. Dorsum sellae and posterior clinoids visualized in the shadow of the foramen magnum
27
For the lateral position of the skull, what is the CR location?
2 inches superior the EAM
28
For the lateral position of the skull, what is the CR angulation?
none
29
For the lateral position of the skull, what is the patient/part position?
skull in true lateral. IPL perp to IR and IOML perp to front edge of IR. MSP parallel to IR
30
For the lateral position of the skull, what is the anatomy demonstrated?
entire cranium and superimposed parietal bones of cranium. Entire sella turcica, including anterior and posterior clinoid processes and dorsum sellae. Sella Turcica and clivus are in profile
31
For the PA Axial Projection (Caldwell Method) of the skull, what is the CR location? Angle?
exit at nasion / 15* caudad
32
For the PA Axial Projection (Caldwell Method) of the skull, what is the patient/part position?
pts nose and forehead against table. MSP perp to IR. OML perp to IR
33
For the PA Axial Projection (Caldwell Method) of the skull, what is the anatomy demonstrated?
greater and lesser sphenoid wings, frontal bone, superior orbital fissures, frontal and anterior ethmoid sinuses, supraorbital margins and crista galli
34
For the PA Axial Projection 25-30° of the skull, what is the CR location?
exit at nasion
35
For the PA Axial Projection 25-30° of the skull, what is the anatomy demonstrated?
greater and lesser sphenoid wings, frontal bone, superior orbital fissures, frontal and anterior ethmoid sinuses, supraorbital margins and crista galli, as well as, the foramen rotundum adjacent to each IOM and the superior orbital fissures are seen within the orbits
36
For the PA Projection of the skull, what is the CR location? angle?
to exit at the glabella / 0* angle
37
For the Submentovertex (SMV) of the skull, what is the CR location?
1 1/2 inches inferior to mandibular symphysis or midway between the gonions
38
For the Submentovertex (SMV) of the skull, what is the CR angulation?
none
39
For the Submentovertex (SMV) of the skull, what is the patient/part position?
erect or supine. IOML is parallel to IR, Rest patients head on the vertex. MSP perp to IR
40
For the Submentovertex (SMV) of the skull, what is the anatomy demonstrated?
foramen ovale and spinosum, mandible, sphenoid and posterior ethmoid sinuses, mastoid processes, petrous ridges, hard palate, foramen magnum and occipital bone
41
What are the basic projections for the facial bones?
Lateral, parietoacanthial (waters method) and PA Axial (Caldwell method)
42
What is the special projection for the facial bones?
Modified Parietoacanthial (modified Waters method)
43
For the Parietoacanthial (waters method) of the facial bones, what is the CR location?
to exit at the acanthion
44
For the Parietoacanthial (waters method) of the facial bones, what is the CR angulation?
none
45
For the Parietoacanthial (waters method) of the facial bones, what is the patient/part position?
pts chin resting against table. MML is perp to IR. OML forms 37° angle with table. MSP is perp to IR
46
For the Parietoacanthial (waters method) of the facial bones, what is the anatomy demonstrated?
IOMs, maxillae, nasal septum, zygomatic bones, zygomatic archers and anterior nasal spine
47
For the lateral of the facial bones, what is the CR location?
zygoma, midway between outer canthus and EAM
48
For the lateral of the facial bones, what is the patient/part position?
affected lateral side of head closest to IR in a true lateral position (Body obliqued) MSP parallel to IR. IPL Perp to IR and IOML perp to front edge of IR
49
For the lateral of the facial bones, what is the anatomy demonstrated?
superimposed facial bones, great wings of the sphenoid, orbital roofs, sella turcica, zygoma, and mandible
50
For the PA Axial (Caldwell method) of the facial bones, what is the CR location? Angle?
exit at nasion / 15° caudad
51
For the PA Axial (Caldwell method) of the facial bones, what is the patient/part position?
pts nose and forehead against table. OML perp to IR. MSP perp to table
52
For the PA Axial (Caldwell method) of the facial bones, what is the anatomy demonstrated?
orbital rim, maxillae, nasal septum, zygomatic bones and anterior nasal spine
53
For the Modified Parietoacanthial Projection (Modified Waters method) of the facial bones, what is the CR location? Angle?
to exit at acanthion / none
54
For the Modified Parietoacanthial Projection (Modified Waters method) of the facial bones, what is the patient/part position?
patients chin and nose against table. LML perp to IR and OML forms a 55° with IR. MSP perp to IR
55
For the Modified Parietoacanthial Projection (Modified Waters method) of the facial bones, what is the anatomy demonstrated?
orbital floors (plates) are perp to IR, which also provides a less distorted view of the orbital rims than the waters projection
56
What are the basic projections for the nasal bones?
Lateral and parietoacanthial (waters method)
57
What is the special projection for the nasal bones?
superoinferior (axial)
58
For the lateral of the nasal bones, what is the CR location?
1/2 inch inferior to the nasion
59
For the lateral of the nasal bones, what is the patient/part position?
pts head on IR in true lateral position (body obliqued). IPL is perp to IR. MSP is parallel to IR. IOML perp to front edge of IR
60
For the parietoacanthial projection (waters method) of the nasal bones, what is the cr location?
to exit at acanthion
61
For the parietoacanthial projection (waters method) of the nasal bones, what is the patient/part position?
patients chin is against table. MSP perp to IR. MML is perp to IR and OML forms 37° angle with table
62
For the parietoacanthial projection (waters method) of the nasal bones, what is the anatomy demonstrated?
IOMs, maxillae, nasal septum, zygomatic bones, zygomatic arches and anterior nasal spine
63
For the superoinferior (axial) of the nasal bones, what is the CR location?
center to nasion (CR will just skim glabella and anterior upper front teeth)
64
For the superoinferior (axial) of the nasal bones, what is the CR angulation?
angle as needed to ensure that the CR is parallel to GAL
65
For the superoinferior (axial) of the nasal bones, what is the patient/part position?
patient is erect or prone with chin on IR. IR perp to GAL with angled supports under IR. MSP perp to CR and IR
66
For the superoinferior (axial) of the nasal bones, what is the anatomy demonstrated?
tangential projection of midnasal and distal nasal bones (with little superimposition of the glabella or alveolar ridge) and nasal soft tissue. Petrous ridges are inferior to maxillary sinuses
67
What are the basic projections of the zygomatic archers?
submentovertex (SMV), oblique inferosuperior (tangential), AP Axial (modified Towne method) and parietoacanthial (Waters method)
68
For the submentovertex (SMV) of the zygomatic archers, what is the CR location?
midway between zygomatic arches at a level 1 1/2 inches inferior to mandibular symphysis
69
For the submentovertex (SMV) of the zygomatic archers, what is the CR angulation?
none
70
For the submentovertex (SMV) of the zygomatic archers, what is the patient/part position?
Pt is erect with chin raised and vertex of skull on IR. IOML is parallel to IR. MSP perp to IR.
71
For the submentovertex (SMV) of the zygomatic archers, what is the anatomy demonstrated?
zygomatic arches are demonstrated laterally from each mandibular ramus
72
For the oblique inferosuperior (tangential) projection of the zygomatic arches, what is the CR location?
zygomatic arch of interest (CR skims mandibular ramus, passes thru arch and skims parietal eminence on the downside)
73
For the oblique inferosuperior (tangential) projection of the zygomatic arches, what is the CR angulation?
none
74
For the oblique inferosuperior (tangential) projection of the zygomatic arches, what is the patient/part position?
Pt is erect or supine with chin raised and vertex of skull on IR. IOM is parallel to IR. Head rotated 15° toward side to be examined and tilt chin 15° toward side of interest.
75
For the oblique inferosuperior (tangential) projection of the zygomatic arches, what is the anatomy demonstrated?
single zygomatic arch, free of superimposition
76
For the AP Axial (modified Towne Method) projection of the zygomatic arches, what is the CR location?
1 inch superior to glabella (to pass thru midarches) at level of the gonion
77
For the AP Axial (modified Towne Method) projection of the zygomatic archers, what is the CR angulation?
30° caudad to OML or 37° caudad to IOML
78
For the AP Axial (modified Towne Method) projection of the zygomatic arches, what is the patient/part position?
patient is erect or supine with back of skull against table. OML is perp to IR (or IOML if pt is unable to depress chin enough). MSP is perp to IR
79
For the AP Axial (modified Towne Method) projection of the zygomatic arches, what is the anatomy demonstrated?
bilateral zygomatic arches, free of superimposition
80
For the parietoacanthial (waters method) projection of the zygomatic arches, what is the CR location?
to exit at acanthion
81
For the parietoacanthial (waters method) projection of the zygomatic arches, what is the CR angulation?
none
82
For the parietoacanthial (waters method) projection of the zygomatic arches, what is the patient/part position?
Pt is erect or prone with chin against table. MML is perp to IR. and OML forms 37° angle with table. MSP is perp to IR.
83
For the parietoacanthial (waters method) projection of the zygomatic archers, what is the anatomy demonstrated?
IOMs, maxillae, nasal septum, zygomatic bones and arches, and anterior nasal spine
84
What are the basic routine projections for the optic foramina?
parieto-orbital (Rhese) and Parietoacanthial (waters method)
85
What is the special routine projection for the optic foramina?
Modified parietoacanthial (modified Waters method)
86
For the parieto-orbital (rhese) projection for the optic foramina, what is the CR location? Angle?
at the midportion of the downside orbit / none
87
For the parieto-orbital (rhese) projection for the optic foramina, what is the patient/part position?
pt erect or supine with head starting in prone position.
MSP perp to IR. AML perp to IR.
Adjust pts head so chin, cheek and nose touch table/upright bucky. Head rotated 37° toward affected side.
The angle formed between MSP and plane of IR is 53°.
88
For the parieto-orbital (rhese) projection for the optic foramina, what is the anatomy demonstrated?
bilateral, nondistorted view of the optic foramen. Lateral orbital margins are demonstrated.
89
For the parietoacanthial (waters method) projection for the optic foramina, what is the CR location? / angle?
to exit at the acanthion / none
90
For the parietoacanthial (waters method) projection for the optic foramina, what is the patient/part position?
Pts chin on grid device. OML 37°. MSP and MML perp to IR
91
For the parietoacanthial (waters method) projection for the optic foramina, what is the anatomy demonstrated?
IOMs, maxillae, nasal septum, zygomatic bones and arches and anterior nasal spine
92
For the modified parietoacanthial (modified waters method) projection for the optic foramina, what is the CR location? Angle?
to exit at acanthion / none
93
For the modified parietoacanthial (modified waters method) projection for the optic foramina, what is the patient/part position?
pt is erect or prone with chin and nose on table/upright bucky. LML is perp to IR. OML forms a 55° angle and MSP is perp to IR.
94
For the modified parietoacanthial (modified waters method) projection for the optic foramina, what is the anatomy demonstrated?
orbital floors/plates and orbital rims
95
What are the basic projections for the mandible?
axiolateral oblique, PA 0° and 20-25° cephalad, and AP Axial (towne method)
96
What are the special projections for the mandible?
submentovertex (SMV) and the orthopantomography - panoramic tomography
97
For the axiolateral oblique projection for the mandible, what is the CR location?
CR to exit mandibular region of interest
(3 options:
1. Angle CR 25° cephalad from ILP
2. angle tube 10° and 15° head tilt
3. tilt head 25°)
(will have to find out which will work on each patient to not have the shoulder superimpose the mandible)
98
For the axiolateral oblique projection for the mandible, what is the CR angulation?
depends on the patient. Could be 25° cephalad, 10° cephalad or none
99
For the axiolateral oblique projection for the mandible, what is the patient/part position?
pt is erect or recumbent with head in true lateral position with side of interest against IR. Mandibular area parallel to IR.
100
For the axiolateral oblique projection for the mandible, what will show:
RAMUS -
BODY -
MENTUM -
GEN. SURVEY -
RAMUS - true lateral
BODY - 30° rotation towards IR
MENTUM - 45° rotation towards IR
GEN. SURVEY - 10-15° rotation best provides a general survey of the mandible
101
For the axiolateral oblique projection for the mandible, what is the anatomy demonstrated?
rami, condylar and coronoid processes, body and mentum of mandible NEAREST the IR
102
For the PA or PA Axial projection for the mandible, what is the CR location?
PA: to exit at junction of lips
PA Axial - to exit at acanthion
103
For the PA or PA Axial projection for the mandible, what is the CR angulation?
PA - none
PA Axial - angled 20-25° cephalad
104
For the PA or PA Axial projection for the mandible, what is the patient/part position?
pts forehead and nose against table/upright bucky. OML perp to IR and MSP perp to midline of IR
105
For the PA or PA Axial projection for the mandible, what is the anatomy demonstrated?
PA - mandibular rami and lateral portion of body
PA Axial - TMJ region and heads of condyles visible thru mastoid processes; condyloid processes are seen well
106
For the AP Axial projection for the mandible, what is the CR location? CR exits at?
35-42° caudad (35 for OML, 42 for IOML) // glabella
107
For the Ap Axial projection for the mandible, what is the patient/part position?
pts posterior skull against table/upright bucky. OML perp to IR or place IOML perp to IR. Add 7° cr angle for IOML. MSP perp to midline of IR
108
For the Ap Axial projection for the mandible, what is the anatomy demonstrated?
condyloid processes of mandible and TM fossae
109
For the submentovertex (SMV) projection for the mandible, what is the CR location? Angle?
to a point midway between angles of mandible OR at a level 1 1/2 inches inferior to mandibular symphysis // none
110
For the submentovertex (SMV) projection for the mandible, what is the patient/part position?
Rest head on vertex of skull. IOML is parallel to IR. MSp perp to midline of IR.
111
On an SMV projection of the mandible, if a patient is unable to extend the neck sufficiently to get the IOML perp to the IR what can be done?
112
For the submentovertex (SMV) projection for the mandible, what is the anatomy demonstrated?
entire mandible and coronoid and condyloid processes
113
For the orthopantomography - panoramic tomography projection for the mandible, what is the cr location? Angle?
slightly cephalic to project anatomic structures, positioned at the same height, on top of one another // none
114
What are the basic routine projections for the paranasal sinuses?
lateral, PA (caldwell method), parietoacanthial (waters method)
115
What are the special projections for the paranasal sinuses?
submentovertex (SMV), and parietoacanthial transoral (open mouth waters method)
116
For the lateral projection for the paranasal sinuses, what is the CR location? Angle?
to a point midway between outer canthus and EAM // none
117
For the lateral projection for the paranasal sinuses, what is the patient/part position?
patient is erect with lateral aspect of head against upright bucky with side of interest closest to IR. Head is in true lateral position. MSP parallel to IR. IPL perp to IR and IOML is perp to front edge of IR.
118
For the lateral projection for the paranasal sinuses, what is the anatomy demonstrated?
all 4 paranasal sinus groups are shown
119
For the PA (Caldwell) projection for the paranasal sinuses, what is the CR location? Angle?
to exit at nasion // none
120
For the PA (Caldwell) projection for the paranasal sinuses, what is the patient/part position?
pt is erect with nose and forehead against upright bucky. OML 15° from horizontal. MSP perp to midline of IR
121
For the PA (Caldwell) projection for the paranasal sinuses, what is the anatomy demonstrated?
frontal sinuses projected above the frontonasal suture. Anterior ethmoid air cells are visualized lateral to each nasal bone, directly below frontal sinuses.
122
For the parietoacanthial projection (Waters method) projection for the paranasal sinuses, what is the cr location? Angle?
exit at acanthion // none
123
For the parietoacanthial projection (Waters method) projection for the paranasal sinuses, what is the patient/part position?
Patient is erect with chin and nose against upright bucky. MML is perp to IR and OML forms a 37° angle with plane of IR. MSP perp to midline of IR
124
For the parietoacanthial projection (Waters method) projection for the paranasal sinuses, what is the anatomy demonstrated?
maxillary sinuses with the inferior aspect visualized free from superimposing alveolar processes and petrous ridges, the inferior orbital rim and an oblique view of the frontal sinuses
125
For the submentovertex (SMV) projection for the paranasal sinuses, what is the CR location?
midway between angles of mandible at a level 1 1/2 to 2 inches inferior to mandibular symphysis
126
If you need to do a SMV projection of the sinuses on a person who can not stand, what can you do?
horizontal beam cross table lateral
127
For the submentovertex (SMV) projection for the paranasal sinuses, what is the anatomy demonstrated?
sphenoid sinuses, ethmoid sinuses, nasal fossae and maxillary sinuses
128
For the parietoacanthial transoral projection (open mouth waters method) projection for the paranasal sinuses, what is the CR location? Angle?
to exit at the acanthion // none
129
For the parietoacanthial transoral projection (open mouth waters method) projection for the paranasal sinuses, what is the patient/part position?
patient is erect with chin and nose against upright bucky. OML forms a 37° angle with IR. MML is perp to IR with mouth closed. MSP perp to midline of IR. Pt will open mouth by "dropping jaw without moving head". This will make the MML no longer perp to IR.
130
For the parietoacanthial transoral projection (open mouth waters method) projection for the paranasal sinuses, what is the anatomy demonstrated?
maxillary sinuses, inferior orbital rim, oblique view of frontal sinuses and the sphenoid sinuses (thru the open mouth)
131
If a patient cannot perform the SMV of the sinuses and you need to see the sphenoid sinuses, what other projection can be done?
Parietoacanthial transoral projection (open mouth waters method)
(note says: a good alternative to demonstrate the sphenoid sinuses for patients who cannot perform the SMV position)
132
how is breathing done on all projections for this section?
suspend respiration
133
How is rotation of the skull determined when looking at a radiograph?
distance from the lateral orbital margin to the lateral cortex of the cranium on both sides. (Distance should be equal.)
134
What determines the correct extension of the neck on a radiograph?
where the petrous ridges are located
135
For the parietoacanthial transoral projection of the sinuses where should be petrous ridges be demonstrated on the radiograph?
just inferior to the maxillary sinuses. (proves there was accurate extension of the neck)
136
On an SMV projection of the sinuses, how can you tell if there is tilt?
equal distance between mandibular ramus and lateral cranial cortex
137
On an SMV projection of the sinuses, how can you tell if there was correct extension of the neck?
the mandibular mentum will be anterior to the ethmoid sinuses
138
ON a parietoacanthial projection of the sinuses, how can you determine if there was adequate neck extension?
Petrous ridges are just inferior to the maxillary sinuses
139
Is the AEC recommended for sinuses?
no
140
For the PA projection of the sinuses, how can you tell if there was correct alignment of the OML and CR?
petrous ridges are located in the lower 1/3 of orbits
141
When performing an axiolateral projection (schuller method) of the TMJ, how many xrays are done?
4 (open rt and lt and closed rt and lt)
142
For the axiolateral oblique projection (modified Law method) of the TMJS, how many xrays are done?
4 (open rt and lt and closed rt and lt)
143
If a patient comes in from a trauma situation and needs xrays of the TMJ, what needs to be done first?
always do routine mandible before TMJ to rule out fracture
144
How can you tell if a radiograph of the mandible has any rotation?
condyloid processes are symmetric and lateral to the cspine
145
An Optional PA axial of the mandible will best demonstrate what?
rami and elongated view of condyloid processes
146
How can you tell if the axiolateral oblique projection of the mandible has sufficient extension of the neck?
no superimposition of the cspine by the ramus
147
ON an axiolateral oblique projection of the mandible how can you tell if there was correct rotation of the head?
ramus and body should be demonstrated without foreshortening.
148
how can you tell if there was accurate positioning on a parieto-orbital oblique projection of the optic foramen?
the optic foramen are in the lower quadrant of the orbit
149
On an oblique inferosuperior (tangential) projection of the zygomatic arches why do you tilt the chin 15°?
to prevent superimposition of the zygomatic arch upon the parietal bone
150
On a superoinferior tangential (axial) projection of the nasal bones radiograph there is superimposition of the frontal bone and upper teeth on the nasal bone, what caused this?
The GAL was not perp to the IR
151
what projection is done for a blowout fracture and orbital fractures?
modified parietoacanthial projection (modified waters method) of the facial bones
152
On the modified waters method of the facial bones, where should the petrous ridges be found?
projected into the lower half of the maxillary sinuses
153
How much of a CR angle is needed if you are wanting to visualize the orbital floor?
30° caudad
154
where are the petrous ridges supposed to be on a PA axial of the facial bones?
lower 1/3 of orbits
155
where are the petrous ridges located in a pareietoacanthial projection of the facial bones?
just inferior to the maxillary sinuses
156
On a PA projection of the skull with 0° cr, where are the petrous ridges?
fill the orbits
157
where are the petrous ridges located on a PA axial with 15° cr angle?
lower 1/3 of orbits
158
Where are the petrous ridges located on a PA axial with 25-30° cr angle?
at or just below the IOM to allow visualization of the entire orbital margin.
159
If you did a PA axial with a caudad cr angulation and the ridges are NOT in the lower 1/3 of the orbits, what has happened?
1. OML was not perp to IR
or
2. CR was angled to caudally
160
If the dorsum sellae is superior to the foramen magnum on an AP axial of the skull what happened?
underangulation of the CR or insufficient flexion of the neck.
161
If the posterior arch of C1 is seen in the foramen magnum on an AP axial projection of the skull what has happened?
over angulation of the CR or excessive flexion
162
From anterior to posterior, the cone-shaped orbits project upward at an angle of ____ and toward the MSP at an angle of ___?
30 and 37
163
A tripod fracture affects what 3 things of the zygoma?
orbital process, maxillary process and arch
164
A fracture that is caused by trauma to the opposite side is termed
contrecoup
165
Give 2 reasons why projections of the facial bones are performed PA rather than AP.
1. reduced OID
2. Reduces exposure to thyroid
166
Distance for all facial and cranial views?
Inches and cm?
40-48 inches and 100-120cm
167
Grids are used for everything but?
Not lateral nasal bones.
168
AEC and mandibles?
NEVER unless doing SMV.
169
AEC and skull?
Always
170
AEC and facial bones?
Always
171
AEC and sinuses?
SMV only. others no.
172
kVp for cranial?
80-85 - all of them but
80-90 SMV
173
kVp for facial bones?
75-85 (waters + caldwell)
70-80 (lat)
174
kVp for mandible?
75-85 all but
75-90 for SMV
175
kVp for sinuses?
75-85 for all.
176
kVp for nasal bones?
60-70 for lateral
