Lecture 6-Skull Flashcards
How do you acess for rotation in a Caldwell skull?
Look at the distance between the orbits and the side of the skull
Where should the petrous ridges be in a Caldwell skull?
Petrous ridges in lower third of orbits
How do you position for a PA caldwell projection?
-Erect PA
-MSP and OML perpendicular to IR
What angle is used for a PA caldwell projection?
15 degrees caudad
What angle is used for an AP caldwell projection?
15 degrees cephalad
What projection is this? What error(s) have been made?
-PA caldwell
-Only needed to collimate to the base of skull
What corrections need to be made to this iamge of the PA caldwell skull?
-Angle 10 degrees more caudad
-Lift the chin so the OML changes 10 degrees
-Rotate nose to the left
If the petrous ridges are in the middle of the orbits in a PA caldwell, what was the angle that was most likely used?
10 degree caudad angle
What corrections need to be made to this image of the PA Caldwell?
-Need to angle caudad an extra 5 degrees or raise the chin so that the OML changes by 5 degrees.
-Nose needs to be rotated towards the right (opp to odontoid rules)
What correction needs to be made to this image of the PA caldwell?
-Nose needs to be rotated towards the left
-Angle 10 degrees more caudad or lift the chin so OML changes by 10 degrees
What errors have been made to this image of the PA caldwell?
-Petrus ridges in a good spot
-Clipped vertex, too much of mandible on image
-Centered incorrectly
What would happen to the petrous ridges in this image if we were to center correctly? What would we have to do to correct this?
Petrus ridges would be too low, so we would have to decrease the caudad angle by 5 degrees or flex the neck so the OML changes by 5 degrees
What corrections need to be made to this image of the PA caldwell?
-Nose needs to be rotated to the right
-Petrus ridges in the middle; increase the caudad angle by 5 degrees, lift the chin 5 degrees
What corrections need to be made to this image of the PA caldwell?
-Extend the neck (looks like a Ruggles with no angle)
-Need to angle 25 degrees
Do we repeat for tilt in skull images?
No
Do we repeat for rotation in skull images?
Yes, most of the time
What errors have been made to this image of the PA caldwell?
-Vertex to the right
-Too wide FOV
What do we hit first in an AP Caldwell?
The orbits
What corrections need to be made to this image of the AP caldwell?
-Decrease the cephalad angle used (don’t need to specify the number) or tuck the chin down
-Rotate the nose to the right slightly
What corrections need to be made to this image of the AP caldwell?
-Rotate the nose towards the right
-Decrease the cephalad angle used or flex the neck
What corrections need to be made to this image of the AP caldwell?
-Center higher, collimate, and rotate nose the right
T/F
The waters method is done AP and PA
True
Where should the petrous ridges be in a waters method?
Petrous ridges below maxillary sinuses or maxillary antrum
What two peices of anatomy is the waters method done for?
Sinuses
Facial bones
What angle is used for the sinus waters method?
No angle
When the MML is perpendicular to the IR, what is the angle of the OML to the bucky?
Angle of the OML=37 degrees from the IR/bucky