radiographic image of tmj

2. Temporomandibular Joint
Imaging

3. Contents
• Introduction to TMJ
• Imaging Modalities of TMJ
• 1. Imaging of osseous structures
• 2. Imaging of soft tissues
• Abnormal Findings in TMJ
• References
• Contents

4. • Temporomandibular Joint
• The TMJ articulation is a joint that is capable of hinge-type
movements and gliding movements. The bony components are
enclosed and connected by a fibrous capsule. The mandibular
condyle forms the lower part of the bony joint and is generally
elliptical, although variations in shape are common. The capsule is
lined with synovium and the joint cavity is filled with synovial fluid.
The synovium is a vascular connective tissue lining the fibrous joint
capsule and extending to the boundaries of the articulating surfaces.
Both upper and
• lower joint cavities are lined with synovium. The synovial membrane.
• Articular Disc
• A fibrocartilage made up primarily of dense collagen of variable
thickness and referred to as a disc occupies the space between the
condyle and mandibular fossa.

5. • Components of TMJ
• 1. Glenoid Fossa & Articular Eminence/Protuberance
• 2. Mandibular Condyle
• 3. Articular Disk & Capsule
• 4. Synovial Fluid
• 5. Discal Ligaments
• 6. Posterior Attachment or Retrodiscal Tissue or Bilaminar
Zone
• 7. Ligaments associated with TMJ
• 8. Muscles of Mastication
• 9. Arterial Supply, Venous Drainage & Sensory Innervation
of TMJ

9. • Assessment Procedure:
•
• 1-Behavioral Assessment
• 2-History
• 3-clinical examination
• 4-Diagnostic imaging
• 5-Dignostic local anesthetic Nerve Block

10. Indications for radiography of TMJ
1. Pain
2. Systemic disease
3. Noise , clicking sounds during movement
4. Masticatory muscle pain
5. Trismus , limitation of mouth opening
6. trauma
7. asymmetrical face
8. morphological abnormalities

11. • Diagnostic Imaging Of TMJ
• The type of imaging technique depends upon the clinical problems
• associated, so either imaging of hard tissue (OSSEOUS) or soft
• tissue is desired.
• Certain protocols are to be taken care before the imaging
procedure:
• The amount of diagnostic information available from particular
• imaging modality.
• The cost of examination
• The radiation dose

13. IMAGING OF
OSSEOUS STRUCTURES
Panoramic Radiograph
Plain Film Radiograph: Transcranial
Projections
Transpharyngeal Projections
Transorbital Projections
Submentovertex Projections
Conventional Tomography
Computed Tomography (CT)

15. Hyperplasia (right TMJ)

16. • • Fibrous Ankylosis
• (upper panoramic)
• – Treated by extensive
• resection.
• • Bony Ankylosis
• (lower panoramic).
• – No visible joint
• space.

17. • Panoramic machines have specific TMJ programs which are of
• limited usefulness.
• • Thick image layers
• • Oblique view/distorted view of the joints
• • Low image quality
• However this imaging modality gives a gross osseous change of
• condyle such as:-
• Asymmetries
• Extensive erosions
• Large osteophytes
• Tumors
• Fractures

18. • However panoramic projections doesn’t provide
informations about
• condylar positions or function.
• Mild osseous changes may be obscured, and only
marked changes
• in articular eminence morphology can be seen as a
result of super
• imposition by the skull base and zygomatic arch.
• For these reasons, the panoramic view should not be
• considered as a sole in imaging modality and be
• supplemented.

19. • Plain Film Imaging Modalities
• The plain film usually consists of combinations of
following
• projections and allows visualization in various
planes:-
• Transcranial Projections
• Transpharyngeal Projections
• Transorbital Projections
• Submentovertex Projections

20. • Transcranial View
• It is a view that aids in visualizing the sagittal view of the
lateral
• aspects of condyle and temporal component. It is taken in
both
• open and close mouth positions.
• Indication Area of joint seen
• TMJ pain dysfunction syndrome Lateral aspect of
Glenoid fossa
• Internal derangement Articular eminence
• Range of movement in joints Joint space
• Condylar head

21. • Film position:
• • flat against patients ear
• • Centered over TM joint of interest
• • Against facial skin parallel to sagittal plane
• Position of patient:
• Head adjusted so sagittal plane is vertical &
ala tragus line
• parallel to floor

22. • Central Ray
• 1. The central ray is direct at an angle of 250 (+ve angulation)
• from the opposite side, through the cranium and above the
• petrous ridge of the temporal bone.
• 2. The horizontal angulation can be individually corrected for
• the condylar long axis, or an average 200 anterior angle may
• be used.

23. • Closed view- size of joint space, position of head of
• condyle, shape & condition of glenoid fossa & articular
• eminence
• Open view- range & type of movement
• Comparison of both sides
• Disadvantages :
• Superimposition of ipsi-lateral petrous ridge over the
• condylar neck

24. Transcranial projections of the left TMJ.
Degree of translatory movement
between the closed view (A) and the open
view(B)
(A) (B)

25. • Transpharyngeal View
• (Parma projection, Macqueen-Dell Technique)
• This technique provides a sagittal view of the medial pole of the
• condyle. It is taken in open mouth position.
• Indication Area of joint seen
• TMJ pain dysfunction syndrome Lateral view:
• Condylar head & neck
• Osteoarthritis & rheumatoid
• arthritis
• Articular surface
• Condylar head- Cyst or tumor
• Fracture of neck & condyle

26. Film placement-
Patient holds the cassette flat against
patients
ear
Centered over TM joint of interest
Against facial skin parallel to sagittal plane
½ inch anterior to EAM
Central ray-
Directed from opp side cranially at
angle(-5 to -10
degrees)
Beneath the zygomatic arch, through
sigmoid notch
posteriorly across pharynx at the condyle
Comparison of both condylar heads

27. • It is taken in the open or protruded position and depicts the entire
• medial lateral aspect of condyle in frontal plane.
• Transorbital Projections

28. • Film position- Behind patients head at an angle of 45 degree to
• sagittal pane
• Position of patient-
• -Sagittal plane vertical
• -Canthomeatal line should be 10 degree to the horizontal with
• head tipped downwards
• Central ray-
• -tube head-front of patients face
• -directed to joint of interest at an angle of +20 degrees to strike
• cassette at right angles

29. • Point of entry -
• - Pupil of the same eye-asking patient to look
straight ahead
• - Medial canthus of the same eye
• Disadvantage :
• If the patient cannot open wide, areas of the joint
articulating
• surfaces will be obscured because of
superimposition

31. Condyle seen below articular eminence

32. Submentovertex Projections
A submentovertex projections
provides a view of skull base and
condyles in a horizontal plane. It is
often used to determine the
angulations of the long axis of the
condylar head so for corrected
tomography.
Indication
1. Evaluating facial asymmetries
2. Condylar displacement

33. • Conventional Tomography
• Tomography is a radiographic technique that produces
multiple
• thin image slices, permitting visualization of an anatomic
structure
• essentially free of superimpositions of overlapping
structures.
• Tomographs typically are exposed in the sagittal (lateral)
plane
• with several image slices in the closed (maximal
intercuspation)
• position and usually only one image in the maximal open
position.

34. • In "corrected“ sagittal tomography, the condylar long axis with
• respect to the midsagittal plane is determined using an SMV
• Projection
• The patient's head is then rotated to this angle, permitting
• alignment of image slices perpendicular to the condylar long
• axis. This minimizes geometric distortion of the joint and
• allows accurate assessment of condylar position.

35. • Computed Tomography (CT)
• Indicated when more information is needed about the
threedimensional
• shape and internal structure of the osseous
• components of the joint or if information regarding the
surrounding
• soft tissues is required.
• Multiple image slices are made in both the axial and
coronal
• planes, although the coronal images are the more useful.
Three
• dimensional reformatted images also can be produced.

36. • These are useful for assessing osseous
deformities of the jaws or
• surrounding structures. CT cannot produce
accurate images of the
• articular disk.
• CT may be considered for determining the
presence and extent of
• ankylosis and neoplasms and the extent of
bone involvement

37. Indications:
• Extent of ankylosis
• Neoplasms-bone involvement
• Complex fractures
• Complications -polytetrafluoroethylene or
silicon sheet implants
-erosions into the middle cranial fossa
• Heterotopic bone growth

38. • • CBCT is the recent technology developed for angiography
in
• 1982 and subsequently applied to maxillofacial imaging.
• • CBCT has the advantage of reduced patient overdose
• compared to medial CT and is likely to replace Conventional
• Tomography.
• • In CBCT the patient is scanned in closed position and low
• resolution scan done in open or other positions.
• CBCT

40. • Soft tissue imaging is indicated when the TMJ pain and
• dysfunction are present and when clinical findings suggest disk
• displacement along with symptoms that are unresponsive to
• conservative therapy. Imaging should be prescribed only when
• the anticipated results are expected to influence the treatment
• plan.
• The imaging modalities for soft tissues are:
• 1. Arthrography
• 2. Magnetic Resonance Imaging (MRI)

41. • Arthrography
• Norgaard (1940)
• It is a technique in which an indirect image of the disk
is obtained
• by injecting a radiopaque contrast agent into the joint
spaces under
• fluoroscopic guidance.
• However MRI has replaced Arthrography in todays
context and is
• now the imaging technique of choice for soft tissues.

42. Indications:
Position and function of disk -pain and
dysfunction- long standing
History of locking-persistent
Perforations of the disk and retrodiskal tissue.
Joint dynamics
Disc displacement-ant/anteromedial
Contraindications:
Infections in the preauricular region.
Patients allergic to contrast media.
Patients with bleeding disorders and on
anticoagulant therapy

44. mri
• • Uses Magnetic field and radiofrequency pulses
• • Bilateral dual surface coils- 0.5 to 2 tesla-
Improve image resolution
• • MRI produces excellent image qualities so is
the principle
• imaging choice for soft tissue.
• Oblique sagittal/oblique coronal scans with t1, t2
• Closed mouth, partially open and fully open
positions

46. • Disk is of low signal intensity (dark grey or black) and
can be
• distinguished from surrounding tissue that has high
signal
• intensity.
• Posterior disk attachment (PDA) shows higher than the
disk
• and the junction between the posterior band of the
disk and
• PDA is distinct.
• Medial disk displacements-best seen

47. MRI of a normal TMJ.
A. Closed view showing the condyle and
temporal component. The biconcave disk
is located with its posterior band (arrow) over
the condyle.
B. Coronal image showing the osseous
components and disk (arrows) superior to
the condyle.
A. B.

48. This sagittal MR image shows anterior disk
displacement in the
closed mouth position. Disc is deformed

49. • Advantages of CT
• • Direct delineation of bony
• structures-surgical anatomy
• • Some soft tissues-lateral
• pterygoid muscle
• • 3-D images from any angle
• • Disadvantages-
• -high radiation exposure
• -soft tissues cant be
• appreciated
• Advantages of MRI
• • Soft tissues-esp disk and its
• association
• • Information in short
• acquisition time
• • Disadvatages-
• -expensive
• -claustophobia