Essen al Projec ons:
Zygoma c Arches
⬤ Submentover cal (SMV)
⬤ Tangen al
⬤ Anteroposterior (AP) axial (modi ed Towne)
⬤ Pa ent posi on
⬤ Seated upright or supine
⬤ If supine, elevate thorax
⬤ Part posi on
⬤ Hyperextend neck to place IOML parallel with IR plane
⬤ Rest head on vertex
MSP perpendicular to IR plane
⬤ CR
➢ Perpendicular to IOML
➢ Enters MSP of throat at level 1 inch (2.5 cm) posterior to outer canthi
➢ Center IR and CR
⬤ Collima on
➢ Exposure eld 8 × 10 inches (18 × 24 cm)
➢ Radia on eld to extend ½ to 1 inch (1.3 to 2.5 cm) beyond the lateral sides of the face,
superiorly to the chin, and inferiorly to the gonions
Tangen al Zygoma c Arches
⬤ Pa ent posi on
➢ Seated upright with back against ver cal Bucky
➢ Supine with trunk elevated
⬤ Part posi on
➢ Hyperextend neck and rest head on vertex
➢ IOML as parallel with IR plane as possible
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➢ Rotate MSP of head 15 degrees toward side being examined
➢ Tilt top of head 15 degrees away from side being examined
➢ Center zygoma c arch to IR
⬤ CR
➢ Perpendicular to IOML
➢ Centered to zygoma c arch at a point 1 inch (2.5 cm) posterior to outer canthus
➢ Centered to IR
⬤ Collima on
➢ Exposure eld 6 × 10 inches (18 × 24 cm)
➢ Radia on eld to ½ inch (1.3 cm) beyond the skin shadow of the a ected cheek,
superiorly to the p of the nose, and inferiorly to the gonion
AP Axial (Modi ed Towne) Zygoma c Arches
⬤ Pa ent posi on
➢ Seated upright or supine
⬤ Part posi on
➢ MSP perpendicular to midline of grid
➢ OML perpendicular to IR plane
•
May use IOML and increase CR angle
⬤ CR
➢ Angled 30 degrees caudad to enter glabella approximately 1 inch (2.5 cm) above nasion
➢ If IOML used, angle 37 degrees caudad
➢ Center IR and CR
⬤ Collima on
➢ Exposure eld 10 × 12 inch (24 × 30 cm)
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➢ Radia on eld to extend ½ to 1 inch (1.3 to 2.5 cm) beyond the lateral sides of the face,
superiorly to the top of the forehead, and inferiorly to the chin