Procedures II: Chapter 11 - Skull positioning

For accurate air-fluid levels

Why is erect positioning preferred for sinuses?

No AEC for sinuses

Can you use AEC for sinuses?

If rotation is present, one is more in front of the other.

What do you look for in rotation?

If tilt is present, one plate is higher than the other

What do you look for in tilt?

• Rami of mandible

• Anterior + posterior clinoid processes

Vertical structures

What structures are seen when rotation is present?

• Body of mandible

• Orbital plates

Horizontal structures

What structures are seen when tilt is present?

Skull routines:

1. PA or PA axial (caldwell)

2. Lateral

3. AP axial (Townes)

What are the routines for skull exam?

Skull lines:

• MSP perpendicular to IR

• OML (30 degrees) or IOML (37 degrees) perpendicular to IR

What lines are used for AP axial projection of Towne’s method for skull?

Skull positioning:

• Pt is seated, back against the board

• Tuck chin to OML

What is the positioning of AP axial projection of Towne’s method of skull?

Skull angle:

• OML: 30 degrees caudad (60 degrees)

• IOML: 37 degrees caudad (53 degrees)

What is the tube angle used for AP axial projection of Towne’s?

Skull CR: 2.5 inches above glabella = hairline

What is the CR for AP axial projection of Towne’s for skull?

Skull demonstration:

• Occipital bone

What is best demonstrated for AP axial projection of Towne’s method for skull?

Skull critique:

• Dorsum sellae and posterior clinoid processes in the shadow of the foramen magnum

• Petrous ridges are symmetrical

How do you critique radiograph of AP axial projection of Towne’s method for skull?

Skull lines:

• MSP parallel to IR (moving left to right)

• IOML parallel to IR

• IP perpendicular

What lines are used for RT and LT lateral method for skull?

Skull positioning:

• Shoulders obliqued

• Head is close to the board “listening”

What is the positioning of RT and LT lateral method for skull?

Skull CR:

• 2 inches above EAM

What is the CR for RT and LT lateral method for skull?

Skull demonstration

• Entire skull is visualized (Frontal + parietal + occipital + temporal)

• Downside parietal bone

What is best demonstrated for RT and LT lateral method for skull?

Skull critique:

• Sella turcica + anterior and posterior clinoid processes + orbital plates + rami of mandible are SUPERIMPOSED

How do you critique radiograph of RT and LT lateral method for skull?

Skull lines:

• MSP perpendicular

• OML perpendicular

What lines are used for PA projection (axial + w/o angle) method for skull?

Skull

• Nose + forehead against the board

What is the positioning of PA projection (axial + w/o angle) method for skull?

Skull CR: Exit at Glabella

What is the CR for PA projection (0 degrees) method for skull?

Skull: Frontal bone

• Best general survey of cranial bone

What is best demonstrated for PA projection (axial + w/o angle) method for skull?

Skull:

• Petrous pyramids filling the orbits

How do you critique radiograph of PA projection (0 degrees) method for skull?

Skull CR: Exits at nasion

What is the CR for PA axial projection (Caldwell) method for skull?

Skull:

• Petrous pyramids are lower 1/3 of the orbit

How do you critique radiograph of PA axial projection (Caldwell) method for skull?

Skull Caldwell angle:

• 15 degrees caudad

What is the tube angle used for PA axial projection (Caldwell) method for skull?

Skull lines:

• MSP perpendicular

• IOML parallel to IR + perpendicular to CR

Special: What lines are used for Submentovertical (SMV) projection of skull?

Skull CR:

• CR: 1.5 inches below mandibular symphysis

Special: What is the CR for Submentovertical (SMV) projection of skull?

Skull demonstration:

• Floor of the cranium

Special: What is best demonstrated for Submentovertical (SMV) projection of skull?

Skull critique:

• Mandibular condyles anterior to petrous pyramids

Special: How do you critique radiograph of Submentovertical (SMV) projection of skull?

PA axial (Haas method)

Special: What is the reverse method of AP Axial Towne’s?

Skull tube angle:

• 25 degrees cephalad

Special: What is the tube angle used for PA axial (Haas method) for skull?

Skull demonstration:

• Occipital bone, petrous pyramids, and foramen magnum

• Dorsum sellae and posterior clinoid processes visualized in the shadow of the foramen magnum

Special: What is best demonstrated for PA axial (Haas method) for skull?

Facial bone routines:

1. Lateral

2. PA axial (caldwell)

3. Parietocanthial (waters)

What are the routines for facial bone?

Facial bone lines:

• MSP + IOML parallel to the IR

• IP perpendicular to IR

What lines are used for RT and LT lateral for facial bone?

Facial bone positioning:

• Shoulders obliqued

• Head is close to the board “listening”

What is the positioning of RT and LT lateral for facial bone?

Facial bone CR:

• Halfway between outer canthus + EAM

What is the CR for RT and LT lateral for facial bone?

Facial bone demonstration:

• Downside facial bone

• Mandible visible (no rotation)

What is best demonstrated for RT and LT lateral for facial bone?

Facial bone critique:

• Tilt: Anterior and posterior clinoids + orbital plates

• Rotation: Rami of mandible is superimposed

How do you critique radiograph of RT and LT lateral for facial bone?

Facial bone lines:

• MSP + MML perpendicular

What lines are used for Parietocanthial Projection: Waters method for facial bone?

Facial bone positioning:

• Chin on the board

What is the positioning of Parietocanthial Projection: Waters method for facial bone?

Facial bone CR:

• CR - exits at acanthion

What is the CR for Parietocanthial Projection: Waters method for facial bone?

Facial bone demonstration:

• Best survey for facial bone

What is best demonstrated for Parietocanthial Projection: Waters method for facial bone?

Facial bone critique:

• Petrous pyramid is below maxillary sinuses

How do you critique radiograph of Parietocanthial Projection: Waters method for facial bone?

Facial bone lines:

• MSP + OML perpendicular to IR

What lines are used for PA axial projection: Caldwell method for facial bone?

Facial bone positioning:

• Nose + forehead on the board

What is the positioning of PA axial projection: Caldwell method for facial bone?

Facial bone CR:

• CR: exits at nasion

What is the CR for PA axial projection: Caldwell method for facial bone?

Facial bone tube angle:

• CR: 15 degrees caudad

What is the tube angle used for PA axial projection: Caldwell method for facial bone?

Facial bone demonstration:

• Orbital rim/base, maxilla, zygoma, nasal
  septum, anterior nasal spine

What is best demonstrated for PA axial projection: Caldwell method for facial bone?

Facial bone critique:

• Petrous pyramids are in lower 1/3 of orbits

How do you critique radiograph of PA axial projection: Caldwell method for facial bone?

Facial bone special lines:

• LML + MSP perpendicular to IR

• OML forms 55 degrees angle with IR

Special: What lines are used for Modified Parietocanthial projection: Modified waters method for facial bone?

Facial bone special positioning:

• Chin and nose against the board

Special: What is the positioning of Modified Parietocanthial projection: Modified waters method for facial bone?

Facial bone special CR:

• CR: Exits at acanthion

Special: What is the CR for Modified Parietocanthial projection: Modified waters method for facial bone?

Facial bone special demonstration:

• Orbital plates are NOT distorted

Special: What is best demonstrated for Modified Parietocanthial projection: Modified waters method for facial bone?

Facial bone special critique:

• Petrous pyramids in lower 1/3 of maxillary sinuses

Special: How do you critique radiograph of Modified Parietocanthial projection: Modified waters method for facial bone?

Sinus routines:

1. Lateral

2. PA Caldwell

3. Parietocanthial (waters)

What are the routines for sinuses exam?

Sinuses lines:

• MSP + IOML parallel

• IP perpendicular

What lines are used for RT and LT lateral for sinuses?

Sinuses CR:

• CR: Halfway between outer canthus + EAM

What is the CR for RT and LT lateral for sinuses?

Sinuses demonstration:

• All four sinuses demonstrated

What is best demonstrated for RT and LT lateral for sinuses?

Sinuses critique:

• Sella in profile

• Tilt: Anterior and posterior clinoids + orbital plates superimposed

• Rotation: Rami of mandible superimposed

How do you critique radiograph of RT and LT lateral for sinuses?

Sinuses lines:

• MSP perpendicular

• OML 15 degrees from horizontal

What lines are used for PA axial: Caldwell for sinuses?

Sinuses positioning:

• Nose + forehead against the board

What is the positioning of PA axial: Caldwell (no angle) for sinuses?

Sinuses CR:

• CR: exits at nasion

What is the CR for PA axial: Caldwell (no angle) for sinuses?

Sinuses demonstration:

• Best demonstrated: Frontal sinuses + anterior ethmoid sinuses

What is best demonstrated for PA axial: Caldwell (no angle) for sinuses?

Sinuses critique:

• Petrous pyramid in lower 1/3 of orbit

How do you critique radiograph of PA axial: Caldwell (no angle) for sinuses?

Sinuses lines :

• MML + MSP perpendicular

What lines are used for Parietocanthial projection: Waters method for sinuses?

Sinuses CR:

• CR: exits at acanthion

What is the CR for Parietocanthial projection: Waters method for sinuses?

Sinuses demonstration:

• Best demonstrated: Maxillary sinuses

What is best demonstrated for Parietocanthial projection: Waters method for sinuses?

Sinuses:

• Critique: Petrous pyramids below maxillary sinuses

How do you critique radiograph of Parietocanthial projection: Waters method for sinuses?

Sinuses special lines:

• IOML parallel to IR

• MSP perpendicular

Special: What lines are used for SMV for sinuses?

Special sinuses positioning:

• Back of head against the board

• Raise chin (hyperextend neck if possible)

Special: What is the positioning of SMV for sinuses?

Special:

• CR: directly perpendicular to IR

Special: What is the CR for SMV for sinuses?

Sinuses special demonstration:

• Sphenoid, ethmoid, maxillary sinuses

Special: What is best demonstrated for SMV for sinuses?

Sinuses special:

• Critique: Mandibular condyles anterior to petrous pyramids

Special: How do you critique radiograph of SMV for sinuses?

Sinuses special lines:

• MML + MSP perpendicular

Special: What lines are used for Parietocanthial transoral projection: Open mouth waters method for sinuses?

Sinuses special positioning:

• Chin on the board

• Extend neck

Special: What is the positioning of Parietocanthial transoral projection: Open mouth waters method for sinuses?

Sinuses special CR:

• exit at acanthion

Special: What is the CR for Parietocanthial transoral projection: Open mouth waters method for sinuses?

Sinuses special demonstration:

• Maxillary, frontal, sphenoid sinuses

Special: What is best demonstrated for Parietocanthial transoral projection: Open mouth waters method for sinuses?

Sinuses special critique:

• Petrous pyramids below maxillary sinuses

Special: How do you critique radiograph of Parietocanthial transoral projection: Open mouth waters method for sinuses?