Temporomandibular Joint (TMJ) XRAY - AP AXIAL (Modified Towne Method)

Tuesday, January 13, 2015

AP Axial Projection - Modified Towne Method - TMJ

Taking TMJ Temporomandibular joints axial projection if patient has possible fracture do not attempt to open mouth.

Pathology Demonstrated and Technical Factors TMJ joint.

Fractures and abnormal relationship/ range of motion between condyle and temporomadibular fossa.
Image receptor used 18 x 24 cm or 8 x 10 inches, put in crosswise.
Moving or stationary grid.
70 to 80 kV range, mAs 16, and Small focal spot.
tmj modified towne
AP AXIAL TMJ (Closed Mouth Position)
if AEC is used, density is reduced to 20% - 30%.

Patient Position and Part Position:

Remove all objects from head and neck like metallic and plastics,
Patient position when taking TMJ joint is ERECT or SUPINE.
Posterior part of of the skull is rested on table or bucky.
Orbitomeatal Line (OML) is perpendicular to image receptor or bucky,
To make IOML perpendicular to CR angle central ray by 7°.
MSP of patient is in midline to avoid head rotation and tilt.

Central Ray and Collimation:

Central ray is 35° caudad from OML or 42° from IOML.
Central Ray is directed to 1 inch anterior level of temporomandibular joint or 2inches to EAM.
Image receptor is in the center of Central Ray.
SID 40 inches.
Collimate on region of interest.

Patient Respiration:

Suspended during exposure.

When patient conditions allows, these projections are taken open and close mouth for comparison on somes departments protocol and to best demonstrate temporomadibular fossae and joints increase cnetral ray angulation by 7°.

Radiographic Criteria:

Structure must be shown on these projection are Condyloid processes of mandible a
tmj modified towne
AP Axial Projection (Closed Mouth)
nd temporomandibular joint and fossae.
Correct Positioning:

Patient with no rotation indicates the ff:

Condyloid process is shown symmetrical, lateral to the cervical spine, clear visualization of condyle
and TM fossae relationship.

Collimation and Central Ray:

Condyloid process of the mandible and the TMJ and fossa are in collimated field. and TMJ must be in center.

Correct Technic Factor used:

Contrast and density are sufficient to visualize condyloid process and temporomadibular fossa.
Sharp bony margins indicate no motion.

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