Mandible

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					The mandible is the largest,
 densest bone of the face
PA Mandible
Lateral Mandible
What are the alveolar processes?



    Spongy bone on superior surface
       of mandible (maxillae) that
    presents excavation for reception
        of roots of teeth-Sockets
The Mandible is one of two non-paired
         bones of the face

         What is the other?


         If you said Occipital-
       you are wrong! That is a
              cranial bone!

        The Vomer is the other
        non-paired facial bone!
 Basic Routine Projections for Mandible



PA
Bilateral   Axiolateral Obliques
SMV (optional)
Notice- there is no lateral
projection- why not?

  The two halves of mandible
 would be superimposed-thus
 obscuring information for both
             sides.
Mandible-PA - Ramus
Mandible-PA-Ramus   (General survey)




               Similar  to a PA
               skull-nose and
               forehead against IR
               CR- 0 Degrees
               Exit at tip of nose
               (acanthion)
               8x10 cassette,
               collimated
                (body and mentum
               superimposed on spine)
Evaluation Critera - PA Mandible

                          Mandibular
                          body and rami
                          symmetric
                          include entire
                          mandible
                          collimate
                          Interpupillary
                          line horizontal
                          midsag.plane
                          perpendicular
PA Mandible-Body



               Similar to PA for
                Ramus, except chin
                and nose against IR

               0 degree CR angle
PA Mandible -Body



                  Ramus
                  Mentum
                  Body
                  Angle
PA - Body   PA - Ramus
A pretty decent AP mandible can be obtained by doing a

                   C-spine odontoid




         R
  Mandible- axiolateral oblique
Both left and right oblique projections must
always be performed!



Blow to one side of jaw transfers force to
opposite side, possibly breaking that side,
not necessarily fracturing side of impact
Mandible- axiolateral obliques –
        3 variations

 Ramus (lateral)
 Body (30 degrees internally rotated)
 Symphysis (45 degrees internally rotated)


     CR angled up 25 degrees in all projections!
  Mandibular axiolateral obliques

Ramus         Body         Symphysis




 A            B            C
Mandibular Axiolateral oblique for Ramus



                           Head  true lateral
                           CR angled 25
                           degrees up
                           extend chin to
                           avoid
                           superimposition
                           on spine
 Axiolateral oblique-Ramus




    TMJ    A
CONDYLE    B
CORONOID   C

   RAMUS   D
    BODY   E


   ANGLE F
Axiolateral oblique - Mandibular Body



                          Similar  to ramus
                          oblique, but rotate
                          head 30 degrees to
                          IR (mand. Body of
                          interest will be
                          parallel to IR)
                          CR 25 degrees up
                          through area of
                          interest
           Axiolateral oblique-mandibular body


                                      Evaluation
                                      criteria
                                      -no overlap of
                                      body by
Coronoid   •A                         opposite body
                                      no cervical
 Ramus     •B                         spine
   Body    •C                         superimposition
                                      no distortion of
   Hyoid   •D
                                      body

   Angle   •E
Mandibular Axiolateral oblique - symphysis



                               No  overlap of
                               mentum
                               no
                               foreshortening
                               (spine will
                               overlap body)
       Mandible-axiolateral oblique




           LAO                       LPO
Shoulder super-imposition problem!
         Mandible-axiolateral oblique (tip!)
Why    struggle to
get patient into
zero tilt lateral, and
then angle 25
degrees up?

Use  tilted head to
your advantage!


     tilt of head
     + CR angle
      25 degrees
       Mandible -SMV              (optional)




For visualizing mandibular body and coronoid
        & condyloid processes of rami
Mandible -SMV
             Similar to skull, but
              collimated to
              anterior portion of
              cranium
             IOML parallel to IR
              (tilt cassette forward if
              possible)
             CR Perpendicular
              to IOML, midway
              between angles of
              mandible
SMV- alternate projection
            Mandible- SMV Evaluation Criteria

                                        Distance
                                        between lateral
Symphysis A
                                        border of skull and
                                        mand. Equal on
   Body      B                          both sides
 Coronoid                               condyles anterior
          C
 process                                to pars petrosae
   Ramus D                              Symphysis
  Condyle E                             extendng to
                                        anterior border of
  Petrous    F                          face
  ridge
               The Hyoid Bone!

What is the
only bone of
the human
body that
does not
articulate
with any
other bone?
Hyoid Bone

            Attaches from
             the styloid
             processes of
             temporal bone
             to tongue
            No views to
             demostrate
 While not always necessary or useful, it is
best to give the patient as much shielding as
    they feel they need for their safety--
REVIEW      A- Coranoid
             process
            B- mandibular
             fossa
            C- neck of
             condyle
            D- Condyle
            E- condylar
             process
            F- Ramus
            G- Gonion
            H- Body
            I-Alveolar
             process
Where is the Sella Turcica?
1 Sphenoid
  bone
Sella Turcica - lateral view
                           Literally means
                            “Turkish
                            Saddle”

                           Superior
                            surface of
                            Spenoid

                           hypophysis =
                            pituitary gland
Pituitary Gland sits inside Sella Turcica
                           Once   thought to be
                           master gland- itself
                           is regulated by
                           hormones from
                           hypothalamus


                           Controls  release of
                           hormones to thyroid,
                           gonads, adrenal
                           cortex (growth,
                           maturation, reproduction)
Sella Turcica series is largely obsolete!


   If film readout is negative, could be
    diagnostic x-ray not sensitive enough to
    detect problem - need an MRI or CT

   If positive, patient sent to CT or MRI for
    more detailed evaluation anyway

   (CT for bone, MRI for soft tissue)
PA Axial - SellaTurcica

                     Head   and
                     nose rest on IR
                     ( like Skull)
                     CR 10
                     degrees
                     cephalic
                     CR exits at
                     Glabella
                     Collimate to
                     4” X4”
PA Axial - Sella Turcica




         Imae
     Evaluation Criteria - PA Axial Sella X-ray


   No rotation of cranium
   Symmetric petrous
    ridges
   Close beam
    restriction!
Lateral Sella Turcica


                   Anterior    Clinoids
              A
                   Posterior   Clinoids
               B
                   Dorsum   Sellae
               C

               D   Hypophysis    (pituitary)


               E   Sphenoid      sinus
Sella Turcica -Lateral
              Mid-sagittal  plane is
              parallel with plane of
              IR
              IPL is perpendicular
              to IR
              IOML is parallel with
              transverse axis of film

              i.e.--same  as Lateral
              skull and sinus and
              facial bones!
Sella Turcica -lateral
        cont’d

                 Upright or semi-
                 prone (crosstable)
                 8X10 cassette
                 CR perpendicular to
                 IR 3/4”anterior,
                 3/4” superior to
                 EAM
                 Collimate to
                 about 4” by 4”
       Evaluation Criteria - Sella Turcica

Sella    in center of
film
Sella   Turcica not
rotated
Anterior clinoids
superimposed
Posterior
clinoids
superimposed

Close   beam
restriction

				
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posted:8/18/2011
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