Download Critique of the Cranium

Critique of the Cranium
Chapter 9
PA and AP projection
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Facility Identification
Correct Marker Placement
No Preventable Artifacts
Correct Film Size
PA and AP projection
 Contrast and density are adequate to
demonstrates air-filled cavities and
bony structures
 Penetration is sufficient to
demonstrate bony trabecular patterns
and cortical outlines
PA and AP projection
 True PA
 The distances from the oblique orbital
lines to the lateral cranial cortices are
equal
 The distance from the Crista galli to the
lateral cranial cortices are equal
PA and AP projection
 Detecting rotation
 The patient’s face is rotated away from
the side that exhibits the greatest
distance between the Orbital rim and the
lateral cortical border of the cranium
PA and AP projection
 OML perpendicular to film
 The petrous ridges should superimpose
the supra orbital rims
PA projection
 Evaluating OML position
 If petrous ridges are below supra-orbital
rim, the chin is too high (will look like a
Caldwell view)
 If petrous ridges are superior to the
supra-orbital rim, the chin is too low.(
will look like a Towne’s view)
AP trauma projection
 Instead of moving head, angle central
ray so that if forms a perpendicular
angle with the OML
 Evaluating OML position
 If the petrous ridges are below the
supra-orbital rim, angle tube more
caudal
 The central ray should be angled the way
that you want the orbits to move.
PA and AP projection
 The nasal septum and Crista galli
should be aligned with the film and in
the approximate center of the film
Caldwell Method (AP or PA)
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Facility Identification
Correct Marker Placement
No Preventable Artifacts
Correct Film Size
Caldwell Method (AP or PA)
 Contrast and density are adequate to
demonstrates air-filled cavities and
bony structures
 Penetration is sufficient to
demonstrate bony trabecular patterns
and cortical outlines
Caldwell Method (AP or PA)
 True PA
 The distances from the oblique orbital
lines to the lateral cranial cortices are
equal
 The distance from the Crista galli to the
lateral cranial cortices are equal
Caldwell Method (AP or PA)
 Detecting rotation
 The patient’s face is rotated away from
the side that exhibits the greatest
distance between the Orbital rim and the
lateral cortical border of the cranium
Caldwell Method (AP or PA)
 If the angle between the OML and the
film is perpendicular and the OML and
the Central ray form a 15 degree
angle, then
 The petrous ridges should be
projected through the lower 1/3 of
the orbits.
Caldwell Method PA
 If the petrous ridges are in the upper
portion of the orbit,(1) the OML was
not perpendicular to film or
 (2)The OML and central ray did not
form a 15 degree angle
 (1) raise the chin
 (2)increase angle
Caldwell Method PA
 If the petrous ridges are inferior to
the orbital rims,(1) the OML was not
perpendicular to film or
 (2)The OML and central ray did not
form a 15 degree angle
 (1) lower chin
 (2) decrease angle
Caldwell PA
 The petrous ridges move with the
back of the head in the PA position
 Raising chin moves petrous ridges down
 Lowering chin moves petrous ridges up
 Central ray moves the orbits,
 Increasing angle moves orbits down
 Decreasing angle moves orbits up
AP axial – Towne’s Position
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Facility Identification
Correct Marker Placement
No Preventable Artifacts
Correct Film Size
AP axial – Towne’s Position
 Contrast and density are adequate to
demonstrates air-filled cavities and
bony structures
 Penetration is sufficient to
demonstrate bony trabecular patterns
and cortical outlines
AP axial – Towne’s Position
 No rotation
 The distances from the posterior clinoid
process to the lateral borders of the
foramen magnum on either side are
equal
 The petrous ridges are symmetrical
 The dorsum sellae is centered within the
foramen magnum
AP axial – Towne’s Position
 The face is rotated toward the side of
the patient which demonstrates the
least amount of distance between the
posterior clinoid processes and the
lateral foramen magnum
AP axial – Towne’s Position
 If the OML is perpendicular with the
film and the CR is 30 degrees with
the OML
 The dorsum sellae and posterior clinoid
are demonstrated within the foramen
magnum without foreshortening or
superimposing of the atlas’s posterior
arch
AP axial – Towne’s Position
 If dorsum sellae is projected inferior
to the foramen magnum
 The OML is not perpendicular with the
film and the patient's chin is raised
 Central ray needs to be increased
AP axial – Towne’s Position
 If dorsum sellae is projected superior
to the foramen magnum and
superimposes the atlas's arch
 The OML is not perpendicular with the
film and the patient's chin is too low
 Central ray needs to be decreased
AP axial – Towne’s Position
 The sagittal suture and nasal septum
are aligned with the long axis of the
film
 The inferior occipital bone is centered
on the film
 The outer cranial cortex, petrous
ridges, dorsum sellae and foramen
magnum are on the film
Lateral Position
cranium – facial bones - sinus
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Facility Identification
Correct Marker Placement
No Preventable Artifacts
Correct Film Size
Lateral Position
cranium – facial bones - sinus
 Contrast and density are adequate to
demonstrates air-filled cavities and
bony structures
 Penetration is sufficient to
demonstrate bony trabecular patterns
and cortical outlines
Lateral Position
cranium – facial bones - sinus
 True lateral
 The sella turcica is demonstrated in
profile
 The orbital roofs, mandibular rami,
greater wings of sphenoid, external
auditory canals, and cranial cortices are
superimposed
Lateral Position
cranium – facial bones - sinus
 Detecting rotation
 The sella turcica will e distorted
 The mandibular rami, greater wings of
sphenoid, EAC will be demonstrated
anterior to one another.
Lateral Position
cranium – facial bones - sinus
 Detecting tilt
 The orbital roofs, greater wings of
sphenoid, and EAC will appear superior
to one another
Lateral Position
cranium
 An area 2 inches above the EAM is in
the center of the film
Lateral Position
facial bones - sinus
 The greater wings of sphenoid are in
the center of the film
Submentovertex
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Facility Identification
Correct Marker Placement
No Preventable Artifacts
Correct Film Size
Submentovertex
 Contrast and density are adequate to
demonstrates air-filled cavities and
bony structures
 Penetration is sufficient to
demonstrate bony trabecular patterns
and cortical outlines
Submentovertex
 True SMV
 IOML is parallel with image receptor
 Mandibular mentum is demonstrated
anterior to the ethmoid sinus
 The distances between the mandibular
rami and the cranial cortex on either side
is equal
Submentovertex
 If mandibular mentum lies to far
anterior to ethmoid sinus
 Head was tilted back to far
 If mandibular mentum overlies
ethmoid sinus
 Head was not tilted enough
 The most common error
Submentovertex
 Detecting tilt
 The distances between the mandibular
rami and the outer cortex of the skull are
not equal
 The side that exhibits the greatest
distance is the side that the cranial
vertex is rotated toward
Submentovertex
 The vomer and bony nasal septum
are aligned with the long axis of the
collimated field.
Submentovertex (basilar
position)
 The dens is in the center of the film
Submentovertex
 The sphenoid sinuses are in the
center of the film
SMV for Zygomatic arches
 If right zygomatic arch is visalized,
head is rotated toward the right
 The head is rotated toward the side of
interest
Parietoacanthal Projection
Waters Position
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Facility Identification
Correct Marker Placement
No Preventable Artifacts
Correct Film Size
Parietoacanthal Projection
Waters Position
 Contrast and density are adequate to
demonstrates air-filled cavities and
bony structures
 Penetration is sufficient to
demonstrate bony trabecular patterns
and cortical outlines
Parietoacanthal Projection
Waters Position
 No rotation
 The distances from the outer rim of the
orbit to the outer cranial cortices are
equal
 The distance from the bony nasal septum
to the lateral cranial cortex on either side
are equal
Parietoacanthal Projection
Waters Position
 Detecing rotation
 If the distance from the orbital rim to the
cranial cortices are not equal
 The side that exhibits the greatest
distance is the side that the patient’s
face is rotated away from
 The side with the least amount of
distance is the side in which the face was
rotated toward
Parietoacanthal Projection
Waters Position
 OML forms a 37 degree angle with
the image receptor
 The petrous ridges should appear
below the maxillary sinus
Parietoacanthal Projection
Waters Position
 If petrous ridges are too low
 Lower chin
 Angle tube cephalic
 If petrous ridges are too high
 Raise chin
 Angle tube caudal
Parietoacanthal Projection
Waters Position
 The bony nasal septum is alighned
with the long axis of the film
Parietoacanthal Projection
Waters Position
 All 4 sets of sinus are demonstrated
on an open mouth view
Orbits
 The optic foramen is open and in the
lower half of orbit, and adjacent
orbital margins
 Tuck the chin until the AML is
perpendicular to IR
 Rotate the head toward the affected
orbit until the midsagittal plane is at
a 53 degree angle with the IR
AML Alignment
 If correct the foramen in the half of
orbit.
 If chin not tucked enough>the
foramen will superimpose the inferior
orbital margin.
 If chin tucked to much> the foramen
will be in the superior half of the orbit
Degree alignment
 If head is less than 53 degrees> the
foramen will be closer to the center of
the orbit
 If rotated more than 53 degrees> the
foramen will superimpose the lateral
margin
Anatomy
 The optic canal and foramen are
centered to IR
 Optic canal, foramen, lesser wing of
sphenoid, and the orbital margins
 8x10 cassette
THE END