Extra Oral Flashcards
what are the 3 extra oral views related to the mandible?
postero-anterior mandible
lateral oblique of mandible
DPT
what are the 3 extra oral views relating to the maxilla and cranium?
lateral cephalogram
occipito-mental views
sialography
what are the 3 positioning landmarks?
radiographic base line
frankfort plane
maxillary occlusal plane
where is the radiographic base line?
outer canthus of eye to EAM
where is frankfort plane?
IOB to upper border EAM
where is the maxillary occlusal plane?
ala of nose to tragus of ear
what extra oral view uses the frankfort plane?
DPT
what extra oral view uses the maxillary occlusal plane?
cone beam CT
What equipment do you need?
skull unit/ cephalometric unit
image receptor
anti-scatter grid
what is Compton scattering?
when x-rays pass through tissues some are scattered
what is used to stop scattering?
anti-scatter grid
what does scattering result in?
grey image lacking contrast
what does an anti-scatter grid contain?
lead slats alternating with plastic
what is a postero-anterior mandible view used for?
fractures medio-lateral displacement
cysts and malignancy causing medio-lateral expansion/ bone destruction
good visualisation of posterior body and ramus
what position is patient for PA mandible?
facing film
RB horizontal 90 degree to film
centre of beam to mid-line of patient