Mandible And TMJs Flashcards
Mandible structure
• Largest and densest bone of the face
• Body is the horizontal portion
• Rami (2) vertical portion
• Body and Rami unite to form the gonion
PA MANDIBULAR BODY Positioning
• IR: 10”x12” LW
• Position: Seated or prone
• Begin with MSP ⟂ to IR
• Rest Nose and Chin on the bucky (placing the AML nearly ⟂ to the IR)
• CR : Perpendicular to the level of the lips
• Collimation: 8X10
• Marker in light field
• Breathing: Suspend
PA MANDIBULAR BODY Evaluation Criteria
• Evidence of proper collimation and presence of the side marker placed clear of anatomy of interest
• Entire mandible
• No rotation or tilt, demonstrated by:
• Mandibular body symmetric on each side
• MSP of head aligned with long axis of collimated field
PA MADIBULAR RAMI Positioning
• IR: 10”x12” LW
• Position: Seated or prone
• Begin with MSP ⟂ to IR
• Rest Forehead and nose on the IR
• OML ⟂ to the IR
• CR : perpendicular exiting the acanthion
• Collimation: 8X10
• Marker in light field
• Breathing: Suspend
PA MANDIBULAR RAMI Evaluation Criteria
-Structures shown: The mandibular body and rami
-Evaluation Criteria:
• Evidence of proper collimation and presence of the side marker placed clear of anatomy of interest
• Entire mandible
• No rotation or tilt, demonstrated by:
• Mandibular body and rami symmetric on each side
• MSP of head aligned with long axis of collimated field
PA AXIAL MANDIBULAR RAMI
the central part of the mandibular body is not well shown because of the superimposed spine
PA AXIAL MANDIBULAR BODY Positioning
• IR: 10”x12” LW
• Position: Seated or prone
• Begin with MSP ⟂ to IR
• Rest Nose and Chin on the bucky (placing the AML nearly ⟂ to the IR)
• CR : 30 degrees cephalad between TMJs
• Collimation: 8X10
• Marker in light field
• Breathing: Suspend
PA AXIAL MANDIBULAR BODY Evaluation Criteria
-Structures shown: The mandibular body and rami
-Evaluation Criteria
• Evidence of proper collimation and presence of the side marker placed clear of anatomy of interest
• Entire mandible
• TMJs just inferior to the mastoid process
• No rotation or tilt, demonstrated by:
• Symmetric Rami
• MSP of head aligned with long axis of collimated field
AXIOLATERAL AND AXIOLATERAL OBLIQUE MANDIBLE Positioning
• SID: 40” IR: 10”x12” LW
• Position: Seated, semi-prone, or semi-supine
• Begin with IPL ⟂ to IR
• Extend neck to place long axis of mandibular body II to bottom edge of IR
• Rotate to place area of interest II to IR
• Ramus: Head true lateral
• Body: 30º toward IR
• Symphysis: 45º toward IR
• CR: 25º cephalic to pass through ROI
• Collimation: 8”x10”
• Marker in light field
• Breathing: Suspend
** Combination of tilt and CR angulation need to add up to 25 degrees**
AXIOLATERAL AND AXIOLATERAL OBLIQUE MANDIBLE Structures Demonstrated
AXIOLATERAL AND AXIOLATERAL OBLIQUE MANDIBLE Evaluation Criteria
• Ramus and Body
• No overlap of the ramus by the opposite side of the mandible
• No elongation or foreshortening of ramus or body
• No superimposition of the ramus by the cervical spine
• Symphysis
• No overlap of the mentum region by the opposite side of the mandible
• No foreshortening of the mentum region
MANDIBLE SUBMENTOVERTICAL (SMV) Positioning
-Position:
• IOML || to IR
-CR
• Perpendicular to the IOML
• Between the angles of the mandible
-Collimation: 8x10
-Instructions: suspend breathing
MANDIBLE SUBMENTOVERTICAL (SMV) Evaluation Criteria
• Proper collimation and presence of the side marker
• No rotation or tilt, demonstrated by:
• Distance between the lateral border of the skull and the mandible equal on both sides
• MSP of head aligned to long axis of collimated field
• Condyles of the mandible anterior to the pars petrosal
• Symphysis extending almost to the anterior border of the face so that the mandible is not foreshortened
TMJ Anatomy
• Articulation of Condyle and mandibular fossa of the temporal bone
• Slants posteriorly, inferiorly, and medial appx 15 degrees
TMJ Pathology
-Dislocation: Anterior dislocation results in patient not being able to close the mouth
-TMJ Syndrome:
Pain
Clicking and locking of jaw
Difficulty chewing
TMJ AP AXIAL (TOWNE) Open and Closed mouth Positioning
-IR: 10”x12” LW
-Position: supine or seated upright
• MSP is ⟂ to IR
• OML is ⟂ to IR
-CR: 35º caudal
• Centered midway between TMJs 3” above nasion
-Collimation: 8”x10” Marker in light field
-Breathing: Suspend
Expose one image with mouth open (unless contraindicated) and one image with mouth closed
What modification could we make if we couldn’t place the OML perpendicular to the IR for the AP Axial (TOWNE) TMJ?
Using IOML, CR 42 degrees caudal
TMJ AP AXIAL (TOWNE) Open and Closed mouth Evaluation Criteria
• Structures shown: Condyles of the mandible and the mandibular fossae of the temporal bones
• Evaluation Criteria:
• Evidence of proper collimation and presence of the side marker
• No rotation of head
• Minimal superimposition of petrosa on the condyle in the closed-mouth examination
• Condyle and temporomandibular articulation below pars petrosa in the open-mouth position
TMJ AXIOLATERAL (SHULLER) Open and Closed mouth Positioning
-IR: 10”x12” CW
-Position: supine or seated upright
• MSP is II to IR
• IPL is ⟂ to IR
-CR: 25º-30º caudal
• Centered 1/2” anterior to EAM and 2” superior to the upside EAM
-Collimation: 8”x10”
-Marker in light field
-Breathing: Suspend
TMJ AXIOLATERAL (SHULLER) Open and Closed mouth Evaluation Criteria
• Evidence of proper collimation and presence of the side marker placed clear of anatomy of interest
• TMJ anterior to the EAM
• Condyle in mandibular fossa in the closed-mouth examination
• Condyle inferior to the articular tubercle in the open-mouth examination if the patient is normal and able to open the mouth widely
TMJ AXIOLATERAL OBLIQUE (MODIFIED LAW) Open and Closed mouth Positioning
-IR: 10”x12” CW
-Position: semi prone or seated upright
• MSP rotated 15º toward the IR
• IPL is ⟂ to IR
• AML is II with transverse axis of the IR
-CR: 15º caudal
• Exiting the TMJ closest to the IR
• Enters 1.5” superior to the upside EAM
-Collimation: 5X5
-Marker in light field
-Breathing: Suspend
TMJ AXIOLATERAL OBLIQUE (MODIFIED LAW) Open and Closed mouth Evaluation Criteria
• Structures Shown:
• open-mouth position shows the mandibular fossa and the inferior and anterior excursion of the condyle
• closed-mouth position shows fractures of the neck and condyle of the ramus.
• Evaluation Criteria:
• Evidence of proper collimation and presence of the side marker placed clear of anatomy of interest
• Temporomandibular articulation
• Condyle lying in the mandibular fossa in the closed-mouth examination
• Condyle lying inferior to the articular tubercle in the open-mouth projection if the patient is normal and is able to open the mouth widely
