Projections (views) for IAMM
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Per-orbital view – (Occipito-Frontal)
Towne’s view
Stenverse projections – 450 PA
obliques with beam angled 120
cephalad
Per-Orbital View - IAM
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True AP or PA
Central ray
passes in
midline along
the Orbitomeatal plane
Increase kV to
penetrate the
dense petrous
part
IAM
Towne’s - IAMM
Stenvers Projection - Petromastoid
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Head rests on the
forehead, nose and
cheek
IOML parallel to upper
edge of bucky
Midsagittal plane at 450
to the bucky
Central ray, angled 120
cephalad, enters 7-10
cm posterior an 1.5 cm
inferior to the EAM
remote from film
Stenver’s projection
Demonstrates
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Petrous ridge
Cellular
structure of the
mastoid process
Mastoid antrum
The area of the
tympanic cavity
Bony labyrinth
Internal acoustic
canal
Cellular stucture
of the petrous
apex
Mastoids
Fronto-Occipital 350
 Lateral with 250 caudal beam angulation
 Lateral with 150 facial and 150 caudal tube
angulation (Modified Law’s projection)
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Mastoids – Modified law’s
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Head lateral
IOML parallel to upper
edge of cassette
Rotate head towards
face to bring mi sagittal
plane is angled 150
Central ray, angled 150,
caudad, enters 5cm
posterior to and 5cm
superior to EAM remote
from film
Mastoids – Modified law’s
Criteria
 Mastoid process
closest to Film, with
air cells centered to
film
 Opposite mastoid
process lying inferior
and slightly anterior
 Auricle of ear not
superimposing
 TMJ visible anterior
to mastoid