Information on the EVDC

Temporomandibular Joint

Radiograph Requirement

TMJ Radiograph Requirement

Well positioned radiographs of the skull clearly showing the temporomandibular joints (TMJ), taken by the resident,are required. Separate submissions for dog and cat are required.

Positioning and Markers

DV or VD View: Nose to the top, with the patient’s Right side positioned at the Left of the image (as though viewing the ventral surface of the body/head. See the example image included below.

Lateral View: The head/ nose faces to the left permitting direct comparison of L and R lateral views. See the example image included below.

Markers: Both Left and Right markers are to be used even when only one is technically required. Left and Right markers are NOT to be placed where they obscure useful anatomical detail. Enough of each marker must be visible to clearly identify it as such once the images have been cropped.

Standard TMJ Radiograph Series

The techniques described below can be applied to both the cat and dog.

Note that radiopaque markers must be included within the primary beam when obtaining the radiographs indicating left and/or right sides.

A set of TMJ radiographs consists of:

1. A dorsoventral or ventro-dorsal view.

  1. The animal is placed in dorsal or ventral recumbency.
  2. The mouth is closed with the palate parallel to the radiographic film.
  3. The x-ray beam is centred on the midline with the central transverse collimator line passing slightly rostral to both horizontal ear canals. This approximates centring between the joints.

2. Left and right lateral-oblique views providing near mirror images of the joints.

  1. The animal is placed in lateral recumbency.
  2. The mouth may be open or closed.
  3. The joint to be examined should be on the lower side, closest to the radiographic film.
  4. The head is angled slightly by axial rotation (to lift the mandible) and/or by lifting the nose (see below).
  5. The x-ray beam is centred on the joint space that is to be imaged.

Lateral-oblique positioning methods

1. Nose-up rotation view:

  1. Initially position the sagittal plane of the head parallel to the radiographic film
  2. Elevate the nose to between 5° and 20° (lower end for mesaticephalic dogs).
  3. The joint to be examined should now: i) Appear rostral to the opposite joint. ii) Be free from superimposition by other significant skeletal structures or the endotracheal tube.
  4. Position the left and right radiographic markers:

i)For the imaged joint, place the marker on the film close to but not where it will be superimposed on the image of the mandibular body.

ii)Position the marker for the opposite side on the cranium caudo-dorsal to the area of interest.

2. Axial rotation view:

  1. Initially position the head so that the sagittal plane is parallel to the radiographic film.
  2. Looking rostro-caudally, rotate the head between 10° and 20° on its long axis (lower end for mesaticephalic dog), clockwise for the left TMJ and anti-clockwise for the right TMJ.
  3. The joint to be examined should now:
  4. Appear ventral to the opposite joint.
  5. Be free from superimposition with other significant skeletal structures or the endotracheal tube.
  1. Position the left and right radiographic markers:
  2. For the imaged joint, place the marker on the film close to but not where it will be superimposed on the image of the mandibular body.
  3. Position the marker for the opposite side on the cranium caudo-dorsal to the area of interest.

3) Combination of nose-up and axial rotation view:

  1. Initially the sagittal plane of the head is positioned parallel to the radiographic film.
  2. The head is rotated as described for axial rotation.
  3. The nose is elevated as described for nose-up rotation.
  4. The joint to be examined should now: i) Appear rostro-ventral to the opposite joint. ii) Be free from superimposition with other significant skeletal structures or the endotracheal tube.
  5. Position the left and right radiographic markers:
  1. For the imaged joint, place the marker on the film close to but not where it will be superimposed on the image of the mandibular body.
  1. Position the marker for the opposite side on the cranium caudo-dorsal to the area of interest.

Preparation of the Images for Submission

Cropping: The complete skull and both mandiblesare to be included. Crop to remove unnecessary anatomy such as the neck.When cropping the images, leave sufficient of both the left and right markers visible for identification.

Resolution: Use digital radiography orphotograph wet films to create bitmap or high quality JPEG images (about 300dpi). TMJ submissions with images of insufficient resolution for review will be returned unreviewed. Files can be submitted in .pdf format, but use the High Quality Print .pdf setting to prevent pixilation.

Name of file: Name the fileYourLASTName, First name, TMJ Set Canine or Felineand Date taken. (Your name will be replaced by a code number before the submission is sent for review.)

Format: Submit the imaqges as either bitmap or .jpg files or as High Quality Print .pdf files. Do NOT include ANY information identifyinjg you or the facility where the radiographs were made.

Submission

  1. Log into VetDentDMS, click Create a New EVDC document on the Welcome screen, and click TMJ Radiograph Set.On the next screen, click Canine or Feline, then click Save and Next (at the bottom of the screen).
  2. On the next sreen, upload the images, by clicking Attach Multiple Files ( on the top command line). Be sure to click Save Changes (top command line) before clicking Submit in the Yellow window.

Example of a Feline TMJ Radiograph Set

The areas of particular interest are shown in unscreened view.

R : L