Transcript Mandible Lecture - El Camino College

Mandible & TMJ Lecture
RT 233 Week 7
 Hello class,

This is my preliminary lecture, I may add more
slides over the weekend. Please check back
on Sunday evening for any revisions.
Mandible
Mandible
 Only movable bone in
the skull
 Densest & largest facial
bone
 2 bones at birth
 Contains mental
foramina
Temporomandibular Joint
PA Mandible (rami)
 Seated or Prone
 Forehead and nose on
IR
 OML & MSP
perpendicular to IR
 CR perpendicular to exit
acanthion
PA Mandible (rami) Radiograph
 Mandibular rami and
lateral portion of body
are visualized
 Entire mandible without
rotation or tilt
PA Mandible Rami- Diagram
PA Mandible (body)
 Seated or Prone
 Nose and chin on grid
device or table placing
mandibular symphysis
parallel with plane of IR
 AML & MSP
perpendicular to IR
 CR perpendicular to
level of lips
PA Mandible (body) Radiograph
 Contrast and density
are sufficient to view
body and rami
 Sharp bony detail
indicating no motion
PA Axial (rami)
Mandible Positioning
 Seated or Prone
 Forehead and nose on
IR
 OML & MSP
perpendicular to IR
 CR 20- 25 cephalic,
centered to exit
acanthion
PA Axial (rami)
Mandible Radiographs
 TMJ and heads of
condyles are visible
through mastoid
processes.
 Condyloid processes
are well visualized,
slightly elongated.
 Entire mandible with no
rotation or tilt with
adequate density
PA Axial (body)
Mandible Positioning
 Seated or Prone
 Nose and chin on grid
device or table placing
mandibular symphysis
parallel with plane of IR
 AML & MSP
perpendicular to IR
 CR between TMJ’s, 30
cephalad.
PA Axial (body)
Mandible Radiographs
 TMJ’s just inferior to
mastoid process
 Symmetric rami
 Adequate contrast and
density
AP Axial – Towne Method
 OML & MSP
perpendicular to IR
 CR 35-40 caudad
 Centered to glabella
midway between EAMS
and angles of mandible
 If IOML is used increase
CR angle 7 degrees
AP Axial- Towne Method Radiograph
 Demonstrates condyloid
processes
symmetrically
 Clear visualization of
TMJ fossae and
condyle relationship
 Minimal SI of TM fossae
and mastoid portions
Axiolateral Oblique Positioning for
Ramus
 Seated, semiprone or
semisupine
 IPL perpendicular to IR
 Mouth closed- teeth together
 Extend neck, chin jutted
forward
 CR 25 degrees cephalic to
pass through area of interest
Axiolateral Oblique Radiograph for
Ramus
 No overlap of ramus by
opposite side of
mandible
 No elongation or
foreshortening of ramus
 No superimposition of
ramus by c-spine
Axiolateral Oblique Positioning for
Body
 Seated, semiprone or
semisupine
 IPL perpendicular to IR
 Mouth closed- teeth together
 Extend neck, chin jutted
forward
 Rotate pt’s head 30 degrees
toward IR
 CR 25 degrees cephalic to
pass through area of interest
Axiolateral Oblique Radiograph for
Body
 No overlap of body by
opposite side of
mandible
 No elongation or
foreshortening of body
 No superimposition of
body by c-spine
Axiolateral Oblique Positioning for
Mandibular Symphysis
 Seated, semiprone or
semisupine
 IPL perpendicular to IR
 Mouth closed- teeth together
 Extend neck, chin jutted
forward
 Rotate pt’s head 45 degrees
toward IR
 CR 25 degrees cephalic to
pass through area of interest
Axiolateral Oblique Radiograph for
Mandibular symphysis
 No overlap of mentum
by the opposite side of
mandible
 No foreshortening of the
mentum region
Panorex Mandible
 Explain how tube/image
receptor move
 IOML perpendicular
 Stand straight, not
jutting chin forward
 Instruct pt to keep lips
together and tongue on
roof of mouth
Panorex Mandible Radiographs
 Demonstrates teeth,
mandible, TMJ’s
 Density are uniform
across image
 No artifacts
AP Axial Temporomandibular
 Supine or seated upright
 Posterior teeth closed and in
contact
 For open mouth- wide as
possible without chin jutted
forward
 OML perp to IR
 CR 35 caudad, centered
midway between TMJ’s.
 Enters approx 3” above
nasion
AP Axial TMJ Radiograph
 No rotation
 Minimal superimposition
of petrosa on condyle in
closed mouth
 Condyle and TMJ below
pars petrosa in open
mouth
Axiolateral TMJ
 Semiprone or seated
 Center ½” anterior to EAM
 Rest cheek on grid device
 Rotate MSP approx 15
degrees toward IR
 IPL perpendicular
 CR 15 caudad exiting
through TMJ closest to IR
about 1 ½ “ superior to
upside EAM
Axiolateral TMJ Radiograph
 TMJ
 Condyle lying in
mandibular fossa in
closed mouth
 Condyle lying inferior to
articular tubercle in
open mouth
Axiolateral Open mouth
Axiolateral Closed mouth