positioning for mandible and TMJ

Question 1

regular routine for mandible

Answer 1

• PA (w/ OML perpendicular to IR)
• 35 degree axial Towne (for rami and condyle)
• bilateral- 25 degree Axiolateral oblique projections (0 degree rotation)

** alternative for those who can’t hold the Townes: 25 degree PA axial

Question 2

PA mandible

Answer 2

• 110 SID, clean detector, pt facing detector
• OML
• CR to exit near level of the lips (-)
• top of light: two fingers above TEA
• bottom of light: two fingers below mentis (tip of chin)
• collimate to include entire mandible, finger width of light on either side
• marker: bottom corner
• check for tilt and rotation, make sure tube and detector are lined up
• there will be light on the shoulders
• hold still, hold breath

Question 3

35 degree Townes for mandible (AP)

Answer 3

• 110 SID, 35 degree caudad
• top of light: a little light above EAM
• bottom of light: gonion
• OML
• preffered method vs 25 degree PA axial
• side to side: include mandible and a little light on either side
• check for tilt and rotation, line up tube and detector
• hold still, hold breath

Question 4

25 degree PA axial for mandible

Answer 4

** used only if patient cant do OML for townes for mandible

• 110 SID, OML, 25 degree cephalad
• pt facing detector, sitting on stool
• top of light: TEA
• bottom of light: gonion
• pt stay nice and straight, tuck chin down, tons of light will be on back
• hold still, hold breath
• light in between shoulder blades
• (-) around top of shoulder
• line up tube and detector, check for tilt and rotation

Question 5

axiolateral oblique for mandible

“oblique” on console

Answer 5

• 110 SID
• can do AP or PA (AP seems easier and thats what im explaining)
• 15 degree cephalad on tube
• start with pts back almost flat against the detector
• then rotate pt abit (about 45 degrees could be a little less)
• pts face should be in a lateral facing you (make sure their face isnt squished against the IR)
• tilt their head about 10 degrees away from IR, and chin up abit
• side to side: EAM to mentis
• light on side closest to IR
• have pt sitting nice upright and straight
• top of light: above TEA of ear touching detector
• bottom of light: finger below mandible (onside touching detector)
• marker: bottom corner
• hold breath and stay still
• line up tube and detector

Question 6

Axiolateral TMJ (Schuller)

Answer 6

• 30 degree caudad, 110 SID, 10x10 lightfield
• start by setting up lightfield (the size of AEC cell)
• marker in bottom corner
• have pt face you with their ear against detector (want ear right in the middle of the detector)
• shoulder should be touching IR
  (I) in line with TMJ (EAM) approx
• (-) middle line on IR is in line with TMJ touching detector
• close mouth but do not clench teeth, hold breath (mark with a “C” marker)
• same position now change marker to a “O” and have them open their mouth, and hold breath and hold still
• check for tilt and rotation
• line up tube and detector

Question 7

35 degree axial Townes for TMJ (done AP)

Answer 7

• 110 SID, 35-40 degree caudad angle
• size of lightfield: length of ear
• (-) go through TMJ
• (I) on MSP
• looks really tiny on top of head
• OML
• cone to temporomandibular joints
• line up tube and detector
• check for tilt and rotation
  *

Question 8

routine protocol for TMJs

Answer 8

• AP axial projection (35 degree Townes)
• Bilateral axiolateral (schullers) -open and closed mouth
• panoramic tomography
  *