cranium, facial bones, orbits, sinuses, nasal bones+ theory only Flashcards
What is the degree of difference between the OML
and IOML?
7 degrees
What is the degree of difference between the OML
and GML?
8 degrees
what is the CR for PA mandibular rami
perpendicular exiting the acanthion
what structures are visualized on PA projection of ,and mandibular rami
Mandibular body (central part not
shown well) and rami
Medial/lateral displacement of
fractures of rami
how is the patient positioned for PA Axial projection( theory only)
MSP and OML perpendicular to IR
CR for PA axial mandible theory only projection
20 or 25 degrees cephalad
to exit at the acanthion
what structures are visualized PA axial theory only projection
Mandibular body (central part not
shown well) and rami
Medial/lateral displacement of
fractures of rami
Patient position for Axiolateral/axiolateral oblique-theory only
IPL perependicular to IR
Mouth closed teeth together
Ramus – true lateral
Body – rotate head 30 degrees
toward IR
Symphysis – rotate patient’s
head 45 degrees toward IR
CR for Axiolateral/axiolateral oblique -theory only
25 degrees cephalad to
pass directly through the
mandibular region of
interest
If the shoulder will be
projected onto the
mandible:
Adjust MSP of skull with ~
15 degree angle and
adjust CR cephalic angle
to 10 degrees cephalad
what structures are visualized in Axiolateral/axiolateral oblique
Structure that is parallel to IR
Ramus
Body
Symphysis
patient position for SMV- submentovertical theory only projection
MSP perpendicular to IR
IOML as parallel to IR as
possible
CR for SMV (Submentovertical)
Perpendicular to the
IOML and entering the
MSP of the throat at a
level approx. 1 inch
(2.5cm) posterior to
outer canthus
what structures are visualized on SMV projection
Bilateral symmetric image of
the zygomatic arches free of
superimposed structures
Patient position for Tangential projection of zygomatic arches
IOML as parallel to IR as
possible
Rotate MSP of head approx.
15 degrees toward side of
interest
Tilt top of head approx. 15
degrees away from side of
interest
what is the CR for tangential projection of zygomatic arches
Perpendicular to IOML
and centered to
zygomatic arch at a
point approx. 1 inch
(2.5 cm) posterior to
the outer canthus
what structures are visualized on tangential projection of zygomatic arches
Zygomatic arch free of
superimposition
Projection useful in patients
with depressed fractures or flat
cheekbones
what is the patient position of AP Axial (modified Towne) of zygomatic arches
MSP and OML perpendicular
to IR
CR for AP Axial (Modified Towne) -zygomatic arches
Entering the glabella
approx. 1 inch (2.5 cm)
above nasion at an
angle of 30 degrees
caudad
If the patient cannot
flex neck to get OML
perpendicular – adjust
IOML perpendicular and
angle 37 degrees
caudad
what is the patient position for AP Axial projection for TMJs
MSP and OML perpendicular to
IR
what is the CR for AP axial of the TMjs projection
Directed 35 degrees
caudad, centered midway
between TMJ’s and
entering at a point approx.
3 inch (7.6cm) above the
nasion
Open and closed mouth
projections
NOTE: open mouth should
not be attempted with
patients who have had a
recent injury
structures for PA axial tmjs projection
Condyles of the mandible and
mandibular fossae of the temporal
bones
patient position for Axiolateral TMJs projection
Seated upright or
semiprone
Center a point ½ inch
(1.3cm) anterior to EAM
to IR
Place head in lateral
position – affected side
closest to IR
MSP parallel to IR
IPL perpendicular to IR
After making exposure with
patient’s mouth closed,
change IR, then (unless
contraindicated) have the
patient open the mouth
widely
CR for Axiolateral TMJs projection
Directed to
midpoint of IR at
angle of 25 or 30
degrees caudad
CR enters ½ inch
(1.3 cm) anterior
and 2 inches (5cm)
superior to upside
EAM
structures for Axiolateral projection of TMJs
TMJ anterior to EAM
Condyle in mandibular
fossa in close-mouth
examination
Condyle inferior to articular
tubercle in open-mouth
examination if patient is
normal and able to open
mouth widely
PA axial caldwell-cranial bones
-OML perpendicular
-Centered @ nasion
-15 degrees caudad
-Petrous ridges in lower
1/3 of orbits
PA axial caldwell -facial bones
-OML perpendicular
-Centered @ nasion
-15 degree caudad
-Petrous ridges in
lower 1/3 of orbits
PA axial caldwell-sinuses
-OML perpendicular
-Centered at nasion
-Perpendicular CR
15 degree angle
between OML and CR
-Petrous ridges in
lower 1/3 of orbits
PA Axial Caldwell- orbits
-OML perpendicular
- centred @ nasion
-30 degrees caudad
-Petrous ridges below
inferior margin of
orbits
AP Axial Towne- cranial bones
-OML perpendicular
-Center @ 2 ½ inch above glabella,
passing through EAMs, exiting
foramen magnum
-30 degrees caudad
(OML perpendicular)
37 degrees caudad
(IOML perpendicular)
– Dorsum sella within
foramen magnum
Parietoacanthial Waters-facial bone
-center at acanthion
-Perpendicular CR
-OML forms 37 degree
angle to plane of IR
-Petrous ridges below
floor of maxillary
sinus
Parietoacanthial waters-sinuses
-center at acanthion
-Perpendicular CR
-OML forms 37 degree
angle to plane of IR
-Petrous ridges below
floor of maxillary sinus
Parietoacanthial
Waters- nasal bones
-center at acanthion
-Perpendicular CR
-OML forms 37 degree
angle to plane of IR
-Petrous ridges below
floor of maxillary sinus
Parietoacanthial
Waters-orbits=modified waters
-center at acanthion
-Perpendicular CR
OML forms 50 degree
angle to plane of IR
– Petrous ridges within
maxillary sinus
lateral-cranial bones
-perpendicular CR
-Center 32 inches superior to EAM
Lateral - facial bones
- perpendicular CR
-Entering lateral
surface of the
zygomatic bone
halfway between the
outer canthus and
EAM
Lateral -sinuses
-perpendicular CR
-Perpendicular to the bridge
of the nose, at a point ½
inch (1.3 cm) distal to the
nasion
lateral- orbits
-perpendicular CR
-Perpendicular through
the outer canthus
what side+ orientation IR is used for PA axial caldwell cranial bones
- medium IR + lengthwise
CR for PA Axial caldwell cranial bones
15 degrees caudad, exiting nasion
what is the patient position for PA Axial caldwell of cranial bones
-PA upright
-Nose= forehead against IR
-OML aligned perpendicular to IR
-check MSP is straight =no tilt or rotation
collimation for PA Axial caldwell projection of the cranial bones
includes vertex of skull, and lateral skull margins
breathing instructions for PA axial caldwell projection of cranial bones
-suspend
where can you look for rotation on a PA axial caldwell
lateral boarder of skull tpo lateral borders of orbits on each side
where to look for tilt on PA Axial caldwell
-look at petrous pyramids, to see if that are symmetrical
Where to look for OML/CR position on PA Axial caldwell
-too see if teh OML is aligned look to see if petrous pyramids are in the lower 1/3rd
what happens to petrous pyramids if we increase CR caudal angulation?
move further down
IE)15- 25 = they will move out of orbits
how do we fix the petrous pyramids being in the orbits, with perpendicular CR + OML perpendicular
correct by increasing CR caudal angel OR tipping head back
how do we fix the petrous pyramids being out of the orbits( below them)
corrects by decrease in CR caudal angle or tip head down
what IR= orientation is used for AP Axial Towne projection of the cranial bones
-medium IR lengthwise
what is the CR for AP Axial towne projection of the cranial bones
30 degrees caudad (if OML perpendicular); 37 degrees caudad (if IOML
perpendicular) – entering 2.5 inches above glabella, passing through EAM, exiting
foramen magnum
Patient position for AP axial towne projection of the cranial bones
AP upright
* Posterior head against IR
* Tuck chin to bring OML perpendicular to IR
* Adjust MSP straight (no tilt or rotation)
what is the collimation for the AP Axial townes projection of the cranial bones
- Include vertex of skull and occipital bone and lateral skull margins (1 inch
beyond skin line)
what are the breathing instruction for AP Axial townes projection of the cranial bones
suspend
on the AP Axial (Towne) – Cranial bones where do you look for rotation?
- Include vertex of skull and occipital bone and lateral skull margins (1 inch
beyond skin line)
on the AP Axial (Towne) – Cranial bones where do you look for tilt
– Symmetric petrous pyramids
on the AP Axial (Towne) – Cranial bones where do you look for OML/CR postion?
Dorsum sellae and posterior clinoid processes visible within foramen
magnum
what error has occurred if the dorsum sella projects above the foramen
magnum
-insufficient caudal angulation= increase CR caudal angulation OROr tuck patient’s chin down to place OML
perpendicular to IR
what error has occurred if the anterior arch of C1 is laying in the
foramen magnum?
-excessive CR angulation, fix=less CR caudal angulation is
required OR extend patient’s neck to place OML
perpendicular to IR
what is the IR size+orientation for Lateral projection of cranial bones
medium IR, crosswise
what is the CR for lateral projection of the cranial bones
: Perpendicular; entering 2 inches superior to EAM
what is the patient position for the lateral projection of the cranial bones
- Upright – L or R lateral
- IPL perpendicular to IR (no tilt)
- MSP parallel to IR (no rotation)
- IOML perpendicular to front edge of IR (chin lifted slightly)
what is the collimation for the lateral projection of the cranial bones.
Include frontal bone, vertex of skull, and occipital bone (1 inch beyond
skin lin)
what is the breathing instructions for lateral projection of the cranial bones.
suspend
where to look for rotation on the lateral projection of the cranial bones
– alignment/mis-alignment anteriorly-posteriorly
Superimposed orbital roofs and greater wings of sphenoid
Superimposed mastoid regions and EAM
Superimposed TMJs
Sella turcica in profile
where to look for tilt on the lateral projection of the cranial bones
alignment/mis-alignment superiorly-inferiorly
Superimposed orbital roofs and greater wings of sphenoid
Superimposed mastoid regions and EAM
Superimposed TMJs
Sella turcica in profile
IR size + orientation for a PA Axial caldwell projection for the facial bones
Medium IR, lengthwise
what is the CR for A PA axial caldwell projection of the facial bones
15 degrees caudad, exiting the nasion
what is the patient position for a PA axial, caldwell projection of the facial bones
- PA upright
- Nose + forehead against IR
- OML aligned perpendicular to IR
- Check MSP is straight (no rotation or tilt)
what is the collimation fro a PA axial, caldwell projection of the facial bones
Include lateral margins of skull, half of forehead, and
upper incisors
what is the breathing instructions for PA Axial projection of the facial bones
suspend breathing