Positioning for Paranasal Sinuses Flashcards
Essential Projections for Sinuses
Lateral
Posteroanterior (PA) axial (Caldwell method)
Parietoacanthial (Waters method)
Parietoacanthial (Waters method) open-mouth modification
Submentovertical (SMV)
why is upright needed for sinuses
Need upright for fluid levels
how should the CR be ?
CR must be horizontal
What is the view that shows all four sets of sinuses ?
Lateral projection
what does the lateral projection of the sinuses demonstrate
All four sets of sinuses
Anteroposterior (AP) and superoinferior dimensions of paranasal sinuses
Thickness of frontal bone
Detail of side closer to image receptor (IR)
how is the MSP for the lateral projection of the sinuses
Midsagittal plane (MSP) of head parallel with IR plane
how is the IPL for the lateral projection of the sinuses
Interpupillary line (IPL) perpendicular to IR plane
how is the IOML for the lateral projection of the sinuses
Infraorbitomeatal line (IOML) perpendicular to front edge of IR
CR for the lateral projection of the sinuses
Horizontal and perpendicular to IR
Enters ½ to 1 inch (1.3 to 2.5 cm) posterior to outer canthus
Center IR to CR
what does the PA Axial Projection (Caldwell Method) demonstrates
Frontal sinuses above frontonasal suture
Anterior ethmoid air cells
Sphenoid sinuses seen through nasal fossa below or between ethmoids
Petrous pyramids in lower third of orbits
how are the petrous ridges in the PA Axial Projection (Caldwell Method)
Petrous pyramids in lower third of orbits
what is the sphenoid sinuses seen through in the PA Axial Projection (Caldwell Method)
Sphenoid sinuses seen through nasal fossa below or between ethmoids
part position for the PA axial Caldwell
Tilt vertical Bucky down 15 degrees
Rest patient’s forehead and nose on device
what should be centered to IR in PA Axial (Caldwell Method)
Nasion
how is the msp and oml in the PA Axial (Caldwell Method)
MSP and orbitomeatal line (OML) perpendicular to IR plane
how should the patients OML be positioned for PA Axial (Caldwell Method)
Position patient’s OML at 15-degree angle to horizontal CR
CR for PA Axial (Caldwell Method)
Horizontal
Exits nasion
Center IR and CR
how do you get the PA axial caldwell method
either angle bucky or angle the OML 15 degrees
what is demonstrated in the Parietoacanthial Projection (Waters Method
Maxillary sinuses
Petrous pyramids lying inferior to maxillary floor
Frontal and ethmoid sinuses are distorted
what are the four sinuses
frontal, ethmoid, maxillary, and sphenoid
how is the MSP and MML in the
Parietoacanthial Projection (Waters Method)
MSP and mentomeatal line (MML) perpendicular to IR plane
what degree is the OML in the
Parietoacanthial Projection (Waters Method)
37 degrees
how should the head be positioned in the Parietoacanthial Projection (Waters Method)
Hyperextend neck to place OML at 37-degree angle from IR plane
how is the CR in the Parietoacanthial Projection (Waters Method)
CR:
Horizontal
Exits acanthion
how is the patient positioned for the Parietoacanthial Projection (Open-Mouth Waters Method)
Seated erect facing Bucky
MSP centered to midline
how is the head positioned in the Parietoacanthial Projection (Open-Mouth Waters Method)
Hyperextend neck to place OML at 37-degree angle from IR plane
what is the degree of the OML in the Parietoacanthial Projection (Open-Mouth Waters Method)
37 degrees
how is the head positioned in the Parietoacanthial Projection (Open-Mouth Waters Method)
Hyperextend neck to place OML at 37-degree angle from IR plane
how is the MSP and MML in the Parietoacanthial Projection (Open-Mouth Waters Method)
MSP and MML perpendicular to IR plane
what is the CR for Parietoacanthial Projection (Open-Mouth Waters Method)
Horizontal
Exits acanthion
what does the Parietoacanthial Projection (Open-Mouth Waters Method) demonstrate
Sphenoid sinuses through open mouth
Maxillary sinuses
Petrous pyramids lying inferior to maxillary floor
how are the petrous ridges in the open mouth waters method
they lie inferior to maxillary floor
how is the head positioned in the SMV
Hyperextend neck and rest vertex of head on vertical grid device
how is the MSP in the SMV
MSP perpendicular to IR plane
how is the IOML in the SMV projection
Neck extended to place IOML parallel to IR plane
CR for the SMV projection
Horizontal and perpendicular to IOML
Enters MSP ¾ inch (1.9 cm) anterior to level of external acoustic meatus (EAM)
what does the SMV projection demonstrate
Sphenoid and ethmoid sinuses
Mandible
Bony nasal septum
Which sinuses are best demonstrated on the parietoacanthial projection (Waters method)?
Maxillary
Which sinuses are best demonstrated on the PA axial projection (Caldwell method)?
Frontal
