Questions and Answers
What are the routine/special projections for TMJ?
For radiography of TMJs in the closed-mouth position, which teeth must be in contact?
posterior teeth
What is the positioning for AP Axial 'Modified Towne' TMJ?
Occiput rests against IR, chin tucked until OML is perpendicular to IR
The AP axial (modified Towne) for TMJ requires a 35° caudad angle. An additional ______° increase best demonstrates the TM fossae and joint.
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What projection of the TMJ demonstrates the condyloid processes of the mandible and TM fossae?
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What is the positioning for Axiolateral Oblique (modified Law) TMJ?
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Was the patient's mouth closed if the condyle is within the fossa?
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Was the patient's mouth opened if the condyle is in the anterior margin of the fossa?
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What TMJ projection results in greater elongation of the condyles compared with the modified Law method?
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What is the positioning for Axiolateral (Schuller) TMJ?
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What is the positioning for Orthopantomography TMJ?
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Study Notes
TMJ Routine and Special Projections
- Routine projection: AP axial (modified Towne)
- Special projections include:
- Axiolateral 15° oblique (modified Law)
- Axiolateral (Schuller)
- Orthopantomography
Teeth Alignment in Closed-Mouth Position
- In closed-mouth TMJ radiography, posterior teeth must be in contact.
AP Axial "Modified Towne" TMJ Projection
- Patient positioning: Occiput against IR and chin tucked until OML is perpendicular.
- Central Ray (CR): Directed 35° caudad to OML (or 42° if using IOML).
- Centering point: 3 inches above the nasion.
TM Fossae Visualization Enhancements
- An additional 5° increase to the 35° angle improves demonstration of TM fossae and joint.
Anatomy Visualization with Projections
- The AP Axial (modified Towne) projection effectively shows:
- Condyloid processes of the mandible
- TM fossae.
Axiolateral Oblique (Modified Law) TMJ Projection
- Patient positioning: Side of head on IR and IPL perpendicular.
- Rotate the face 15° forward from lateral position.
- CR: 15° caudad, centering at 1.5 inches above the upside EAM, passing through the downside TMJ.
Condyle Positioning and Mouth State
- Condyle within the fossa indicates the mouth is closed.
- Condyle in the anterior margin of the fossa indicates the mouth is open.
Projection for Condyle Elongation
- Axiolateral (Schuller method) projection leads to greater elongation of the condyles compared to the modified Law method.
Axiolateral (Schuller) TMJ Projection
- Patient positioning: Head in true lateral position, side of interest closest to IR, IPL perpendicular to IR.
- CR: 25-30° caudad, centering 1/2 inch anterior and 2 inches superior to the upside EAM.
Orthopantomography for TMJ
- Positioning: IOML parallel with the floor.
- CR and centering are fixed with the unit used.
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Description
Test your knowledge on the routine and special projections for temporomandibular joint (TMJ) radiography with these flashcards. This quiz covers important positioning techniques and patient instructions essential for accurate imaging in TMJ studies.
