Radiographic Features of Temporomandibular Joint and Disorders

Dr. Hadi Munib
Oral and Maxillofacial Surgery Resident

 TMJ Dysfunction
 Radiographic Anatomy
 Diagnostic Imaging
 Radiographic Abnormalities
 Remodeling and Arthritic Conditions
 Ankylosis
 Trauma
 Tumors
 References

 The most common jaw disorder, with 28% to 86% of adults and adolescents showing one
or more clinical signs or symptoms.
 A higher incidence of the disorder has been reported in females, although the reason for
this preponderance is not clear
 Pain in the TMJ or ear or both, headache, muscle tenderness, joint stiffness, clicking or
other joint noises, reduced range of motion, locking, and subluxation.
 In most cases the clinical signs and symptoms are transitory, and treatment is not
indicated.
 A small group of patients (5%) has severe dysfunction which requires a thorough
diagnostic workup, including diagnostic imaging, before treatment is begun

 The TMJs are unique in that, although they constitute two separate joints
anatomically, they function together as a single unit.
 Each condyle articulates with the mandibular fossa of the temporal bone.
 A disk composed of fibrocartilage is interposed between the condyle and mandibular
fossa.
 Synovial Membrane
 Ligaments and muscles restrict or allow movement of the condyle.
 A bony ellipsoid structure.

 The condyle is approximately 20 mm long mediolaterally and 8 to 10 mm thick
anteroposteriorly.
 The superior aspect may be flattened, rounded, or markedly convex, whereas the
mediolateral contour usually is slightly convex.
 The extreme aspects of the condyle are called the medial pole and lateral pole.
 The medial pole is angled posteriorly, forming an angle of 15 to 33 degrees with the
sagittal plane.
 Although the mandibular and temporal components of the TMJ are calcified by 6
months of age, complete calcification of cortical borders may not be completed until 20
years of age

 Located at the inferior aspect of the squamous part of the temporal bone
 Temporal Component of TMJ: Glenoid Fossa and Articular eminence of the temporal
bone
 Articular Eminence; Anterior limit of glenoid fossa and convex in shape
 Its most inferior aspect is called the summit or apex of the eminence
 In a normal TMJ, the roof of the fossa, the posterior slope of the articular eminence,
and the eminence itself form an S shape when viewed in the sagittal plane.
 The most lateral aspect of the eminence consists of a protuberance, called the
articular tubercle, which is a ligamentous attachment
 The fossa and articular eminence develop during the first 3 years.
 Reach mature shape by the age of 4 years.
 Young infants lack a definite fossa and articular eminence
 Pneumatization of the articular eminence is seen radiographically in approximately
2% of patients.
 The mandibular fossa is covered with a thin layer of fibrocartilage.

 Composed of fibrous connective tissue
 Located between the condylar head and mandibular fossa.
 Divides the joint cavity into two compartments, called the inferior (lower) and superior
(upper) joint spaces.
 A normal disk has a biconcave shape with a thick anterior band, thicker posterior band
and a thin middle part. [Medial is thicker]
 Thin Central portion serves as a cushion
 The junction between the posterior band and posterior attachment usually lies within
10 degrees of vertical above the condylar head.
 The disk and posterior attachment are collectively called the soft tissue components of
the TMJ.
 During mandibular opening, as the condyle rotates and translates downward and
forward, the disk also moves forward and rotates so that its thin central portion
remains between the articulating convexities of the condylar head and articular
eminence.
 At maximum opening, the condyle is usually positioned beneath the anterior band of

 Osseous Structures: Plain Radiographs, Lateral Cephalometric, Panoramic,
Conventional Tomography and Computed Tomography

 Provides an overall view of the teeth and jaws, provides a means of comparing left and
right sides of the mandible
 Serves as a screening projection to identify odontogenic diseases and other disorders that
may be the source of TMJ symptoms.
 Specific TMJ programs; these are of limited usefulness because of thick image layers and
the oblique, distorted view of the joint they provide, which severely limits image quality.
 Gross osseous changes in the condyles may be identified, such as asymmetries, extensive
erosions, large osteophytes, tumors or fractures
 No information about condylar position or function is provided because the mandible is
partly opened and protruded when this radiograph is exposed.
 Also, mild osseous changes may be obscured, and only marked changes in articular
eminence morphology can be seen as a result of superimposition by the skull base and
zygomatic arch.
 For these reasons, the panoramic view should not be used as the sole imaging modality
and should be supplemented.

 Combination of transcranial, transpharyngeal (Parma), transorbital, and
submentovertex (basal) projections allow visualization of the TMJs in various
planes.
 The transcranial view is taken in the closed and open mouth positions and depicts
the lateral aspect of the TMJ.
 Transpharyngeal projection is taken in the mouth open position only and depicts
the medial aspect of the condyle.
 Transorbital projection is taken in the open or protruded position and depicts the
entire medial-lateral aspect of the condyle in the frontal plane and is very useful
in detecting condylar neck fractures.
 A submentovertex projection provides a view of the skull base and condyles in the
horizontal plane; it is often used to determine the angulation of the long axes of
the condylar heads for corrected tomography.

 Multiple image slices permitting osseous structures visualization
 Essentially free of all superimpositions and overlapping structures
 This technique can provide multiple image slices at right angles through the joint,
depicting true condylar position and revealing osseous changes
 It is desirable to supplement the sagittal images with coronal (frontal)
tomographs,
 Particularly when morphologic abnormalities or erosive changes of the condylar
head are suspected.
 The entire condylar head is visible in the mediolateral plane.

 CT provides more information about the three-dimensional shape and internal
structure of the osseous components of the joint by providing detailed image slices.
 Conventional CT (sometimes referred to as medical CT and CBCT.
 Both modalities can give excellent images of the osseous structures
 Only conventional CT provides images of the surrounding soft tissues [minimal
number of specific situations.
 CBCT has the advantage of reduced patient dose compared with medical CT and is
likely to replace conventional tomography.
 In CBCT the patient is usually scanned in the closed position and low-resolution
scans can be done in the open or other positions

 CT is also useful for:
 Determining the presence and extent of ankylosis and neoplasms
 The degree of bone involvement in some arthritides
 For imaging complex fractures
 For evaluating complications from the use of polytetrafluoroethylene or silicon
sheet implants
 Erosions into the middle cranial fossa and heterotopic bone growth

 Indicated when TMJ pain and dysfunction are present and when the clinical
findings suggest disk displacement along with symptoms that are unresponsive to
conservative therapy.
 Arthrography was the first imaging modality used to image the soft tissues of the
joint.
 Arthrography 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.
 MRI has replaced Arthrography as it shows the soft tissue structure alongside the
articular disc

 Uses a magnetic field and radiofrequency pulses rather than ionizing radiation to
produce multiple digital image slices
 MRI can provide superb images of soft tissues.
 MRI allows construction of images in the sagittal and coronal planes without
repositioning the patient
 Images usually are acquired in open and closed mandibular positions with use of
surface coils to improve image resolution.
 Sagittal slices should be oriented perpendicular to the condylar long axis.
 The examinations usually are performed with use of T1-weighted, proton-
weighted, or T2-weighted pulse sequences.

 T1-weighted and proton-weighted images best demonstrate osseous and diskal
tissues
 T2-weighted images demonstrate inflammation and joint effusion.
 Rapid Image Acquisition; Fast Scan
 Contraindicated in patients who are pregnant or who have pacemakers,
intracranial vascular clips, or metal particles in vital structures.
 Some patients may not be able to tolerate the procedure because of claustrophobia
or an inability to remain motionless.

 May be broadly categorized as anomalies in the form and size of joint components.
 The most striking radiographic changes usually are seen in the condyle, although the
temporal component also may be deformed, often remodeling to accommodate the
abnormal condyle.

 Developmental abnormality that results in enlargement and occasionally deformity of the
condylar head.
 May have a secondary effect on the mandibular fossa as it remodels to accommodate the
abnormal condyle.
 Proposed etiologic factors include hormonal influences, trauma, infection, heredity,
intrauterine factors, and hyper-vascularity.
 The mechanism may be overactive cartilage or persistent cartilaginous rests, which
increases the thickness of the entire cartilaginous and pre-cartilaginous layers.
 This condition usually is unilateral and may be accompanied by varying degrees of
hyperplasia of the ipsilateral mandible.

 More common in males, and it usually is discovered before the age of 20 years.
 The condition is self-limiting and tends to arrest with termination of skeletal growth,
although in a small number of cases continued growth
 The condition may progress slowly or rapidly.
 Patients have a mandibular asymmetry that varies in severity, depending on the degree of
condylar enlargement.
 The chin may be deviated to the unaffected side, or it may remain unchanged but with an
increase in the vertical dimension of the ramus, mandibular body, or alveolar process of the
affected side.
 Posterior open bite on the affected side.
 Patients may also complain of limited or deviated mandibular opening, or both, caused by
restricted mobility of the enlarged condyle.

 The condyle may appear relatively normal but symmetrically enlarged
 It may be altered in shape (e.g., conical, spherical, elongated, lobulated) or irregular
in outline.
 It may be more radiopaque because of the additional bone present.
 Elongation of the condylar head and neck with a compensating forward bend,
forming an inverted L.
 The cortical thickness and trabecular pattern of the enlarged condyle usually are
normal
 Thicker Anteroposterior dimensions of the affected Ramus

 A condylar tumor, most notably an Osteo-chondromas; is irregular in shape
compared with a hyperplastic condyle. Surface irregularities and continued
growth after cessation of skeletal growth
 Condylar osteoma or large osteophyte that occurs in chronic degenerative joint
disease may simulate condylar hyperplasia.
 Orthodontic Treatment and Orthognathic Surgery

 Failure of the condyle to attain normal size
 The condyle is small, but condylar morphology usually is normal
 The condition may be inherited or may appear spontaneously.
 Some cases have been attributed to early injury or injury to the articular cartilage by
birth trauma or intra-articular inflammatory lesions.
 Congenital abnormalities may be unilateral or bilateral
 Usually are a manifestation of a more generalized condition
 Developmental abnormalities that manifest during growth usually are unilateral.
 Acquired abnormalities are the result of damage during the growth period from sources

 The condyle may be normal in shape and structure but is diminished in size, and the
mandibular fossa also is proportionally small
 The condylar neck and coronoid process usually are very slender and are shortened or
elongated in some cases.
 The posterior border of the ramus and condylar neck may have a dorsal (posterior)
inclination.
 Mandibular asymmetry and occasional dental crowding, depending on the severity of
mandibular underdevelopment.
 The antegonial notch is deepened.
 The associated mandibular hypoplasia is more pronounced if the effect takes place
early in life.

 Condylar destruction from juvenile rheumatoid arthritis;
 Changes in condylar morphology
 Severe degenerative joint disease
 Other arthritic conditions; arthritic disease does not cause mandibular hypoplasia of
the affected side unless it occurs during growth.
 Treatment; Orthognathic surgery, bone grafts, and orthodontic therapy

 Boering’s arthrosis and arthrosis Deformans juvenilis
 A condylar growth disturbance manifests as hypoplasia and characteristic morphologic
abnormalities.
 May be a form of condylar hypoplasia
 Thought to differ in that the affected condyle at one time was normal, becoming
abnormal during growth.
 May be unilateral or bilateral
 Predisposes the TMJ to secondary degenerative changes
 Affects children and adolescents during the period of mandibular growth.
 It is more common in females.
 It may be an incidental finding in a panoramic projection, or the patient may have
mandibular asymmetry, signs and symptoms of TMJ dysfunction, or both.

 The condylar head develops a characteristic “ toadstool ” appearance.
 With marked flattening and apparent elongation of the articulating condylar
surface and dorsal (posterior) inclination of the condyle and neck.
 The condylar neck is shortened or even absent in some cases, with the condyle
resting on the upper margin of the ramus
 Progressive shortening of the ramus on the affected side
 The antegonial notch may be deepened, indicating mandibular hypoplasia.

 Developmental Hypoplasia of the condyle The radiographic appearance may be
very similar.
 Rheumatoid Arthritis
 Severe Degenerative Joint Disease
 Condylar Degeneration after Orthognathic Surgery
 Joint Surgery
 Treatment; Orthognathic Surgery and Orthodontic Treatment

 Resulting in elongation of the coronoid process.
 Developmental variant, the condition usually is bilateral.
 Acquired types may be unilateral or bilateral and usually are a response to restricted
condylar movement caused by abnormalities such as Ankylosis.
 Bilateral developmental coronoid hyperplasia is more common in males, often
commencing at the onset of puberty.
 Patients complain of a progressive inability to open the mouth and may have an
apparent closed lock.
 The condition is painless.

 Best seen in panoramic, Waters, and lateral tomographic views and on CT scans.
 The coronoid processes are elongated, and the tips extend at least 1 cm above the
inferior rim of the zygomatic arch.
 The coronoid processes may impinge on the medial surface of the zygomatic arch
during opening, restricting condylar translation.
 This can be confirmed by using CT imaging.
 The coronoid processes may have a large but normal shape or may curve anteriorly
and may appear very radiopaque.
 The posterior surface of the zygomatic process of the maxilla may be remodeled to
accommodate the enlarged coronoid process during function.
 The radiographic appearance of the TMJs usually is normal.

 Unilateral cases; osteochondroma or osteoma; tumors usually have an irregular
shape.
 Any cause of inability to open; soft tissue abnormalities
 Ankylosis
 An axial CT image with the patient in a wide open position is useful in establishing
coronoid interference to opening
 Treatment; surgical removal of the coronoid process and postoperative physiotherapy

 Double/ Bifid; Vertical depression, notch, or deep cleft in the center of the condylar
head, seen in the frontal or sagittal plane, or actual duplication of the condyle.
 This condition is rare and is more often unilateral, although it may be bilateral.
 May result from an obstructed blood supply or other embryopathy, although a
traumatic longitudinal linear fracture in the condyle
 Usually an incidental finding in panoramic views or anteroposterior projections.
 Some patients have signs and symptoms of temporomandibular dysfunction,
including joint noises and pain

 Depression or notch is present on the superior condylar surface, giving the
anteroposterior silhouette a heart shape.
 In more severe cases a duplicate condylar head is present in the mediolateral plane
 The orientation of the bifid condyle may be anteroposterior or mediolateral.
 The mandibular fossa may remodel to accommodate the altered condylar morphology.
 Differential Diagnosis; vertical fracture through the condylar head.
 Treatment; not indicated unless pain or functional impairment is present

 Abnormality in the position and sometimes the morphology of the articular disk that
may interfere with normal function.
 The disk most often is displaced in an anterior direction, but it may be displaced
antero-medially, medially, or antero-laterally.
 Lateral and posterior displacements are extremely rare.
 The cause of internal derangements is unknown, although parafunction, jaw injuries
(e.g., direct trauma), whiplash injury, and forced opening beyond the normal range
have been implicated.
 Internal derangements can be diagnosed by MRI.

 The disk may resume a normal position with respect to the condyle (called reduction
of the disk) during mandibular opening
 When the disk remains displaced throughout the entire range of mandibular
movement, the term non-reduction is used
 A long standing displaced disk may become deformed, losing its normal biconcave
shape, and it may become thickened and fibrotic.
 Possible complications are degenerative joint disease and perforation through the disk
or (more commonly) the posterior attachment.

 Disk displacement has been found both in symptomatic patients and in healthy
volunteers.
 Suggesting that it may be a normal variant and not necessarily a predisposing factor in
TMJ dysfunction.
 It is not known why some disks remain displaced or why symptoms of pain and
dysfunction are not found in all affected patients.
 Symptomatic patients may have a decreased range of mandibular motion
 Unilateral cases may manifest clinically as mandibular deviation to the affected side on
opening.
 Joint noises are common and may manifest as a click as the disk reduces to a normal
position during mandibular opening and occasionally as a softer click as the disk becomes
displaced again during mandibular closing.

 The disk cannot be visualized with conventional radiography or tomography.
 MRI is the technique of choice
 Condylar position in maximal intercuspation is not a reliable indicator of disk
displacement.
 Diminished range of motion at maximal opening is not a reliable indication of a non-
reducing disk.
 In MRI the normal disk has a low signal intensity (is dark between bone and muscle),
and the signal intensity of the bilaminar zone is usually higher (i.e., lighter).

 In the closed-mouth position, the normal disk is positioned with the posterior
band directly superior to the condylar head and the thin intermediate part
between the antero-superior surface of the condyle and the posteroinferior surface
of the articular Eminence.
 It is important to note that in all positions of mouth opening the thin intermediate
part remains the articulating surface of the disk between condyle and articular
eminence.

 Difficult to diagnose
 Anterior displacement is the most common disk displacement.
 When the mandible is in maximal intercuspation, partial or full anterior disk
displacement is indicated by anterior location of the posterior band of the disk from the
normal position, which is directly superior to the condylar head.
 Indication; Positioning of the posterior band forward so that it sits between the antero-
superior surface of the condyle and the eminence

 During mouth opening, an anteriorly displaced disk may reduce to a normal
relationship with the condylar head during any part of the opening movement.
 In motion studies, this is usually a rapid posterior movement of the disk and it is often
accompanied by an audible click.
 This is referred to as disk reduction and can be diagnosed if the disk is in a normal
position in the open mouth magnetic resonance images

 If the disk remains anteriorly displaced (non-reduction) on opening, it may bend
or deform as the condyle pushes against it
 If the disk remains displaced, it will undergo permanent deformation, losing its
biconcave shape.

 Perforations between the superior and inferior joint spaces most commonly occur in
the retrodiskal tissue just behind the posterior band of the disk
 Can be detected in arthrographic investigations but are not reliably detected with
MRI.
 MRI can indicate alteration in the normal biconcave outline of the disk.
 Disk deformities may be accompanied by changes in its signal intensity, sometimes an
increase in signal.
 Changes to the condyle and temporal component of the joint consistent with
degenerative joint disease often accompany cases with long-standing displaced disks

 Fibrous adhesions are masses of fibrous tissue or scar tissue that form in the joint
space, particularly after TMJ surgery.
 Adhesions are best identified with arthrography by resistance to injection of contrast
agent or they may be detected in MRI studies as tissue with low signal intensity.
 The pressure of injected contrast agent may tear some of these adhesions, resulting in
increased joint mobility after the procedure.
 Joint effusion (fluid in the joint) is considered to be an early change that may precede
degenerative joint disease.
 MRI can detect joint effusion, which presents as an area of high-signal intensity in the
joint spaces in T2-weighted images

 Remodeling is an adaptive response of cartilage and osseous tissue to forces applied to
the joint that may be excessive
 Resulting in alteration of the shape of the condyle and articular eminence.
 This adaptive response may result in flattening of curved joint surfaces, which
effectively distributes forces over a greater surface area.
 The number of trabeculae also increases, increasing the density of subchondral
cancellous bone (sclerosis) to better resist applied forces.
 No destruction or degeneration of articular soft tissues occurs.
 TMJ remodeling occurs throughout adult life, it may be unilateral and does not
invariably serve as a precursor to degenerative joint disease.
 Considered abnormal only if it is accompanied by clinical signs and symptoms of pain
or dysfunction or if the degree of remodeling seen radiographically is judged to be
severe.

 May be asymptomatic
 Patients may have signs and symptoms of temporomandibular dysfunction that
may be related to the soft tissue components, associated muscles, or ligaments.
 Accompanying internal derangement of the disk may be a factor.
 Radiographic Features
 Radiographic changes may affect the condyle, temporal component, or both.
 They first occur on the anterosuperior surface of the condyle and the posterior
slope of the articular eminence.
 The lateral aspect of the joint is affected in early stages, and the central and
medial aspects become involved as remodeling progresses.
 May include one or a combination of the following: flattening, cortical thickening of
articulating surfaces, and subchondral sclerosis

 Severe joint flattening and subchondral sclerosis may be diffi cult to
differentiate from early degenerative joint disease.
 The radiographic appearance of bone erosions, osteophytes, and loss of joint
space are signs signifying degenerative joint disease.
 Treatment; if no clinical signs or symptoms are present, treatment is not
indicated.
 Otherwise, treatment directed to relieve stress on the joint, such as splint
therapy, may be considered.

 Osteoarthritis
 Non-inflammatory disorder of joints characterized by joint deterioration and
proliferation.
 Joint deterioration is characterized by loss of articular cartilage and bone erosion.
 The proliferative component is characterized by new bone formation at the
articular surface and in the subchondral region.
 Deterioration is more common in acute disease, and proliferation predominates in
chronic disease
 DJD happens when the joint’s capacity to adapt to excessive forces (remodel) is
exceeded

 The etiology of DJD is unknown.
 A number of factors may be important, including acute trauma, hypermobility, and
loading of the joint such as occurs in parafunction.
 Internal disk derangements may be contributing etiologic factors.
 DJD can occur at any age, although the incidence increases with age.
 DJD has a female preponderance.
 The disease may be asymptomatic, or may have signs and symptoms of TMJ
dysfunction, including pain on palpation and movement, joint noises (crepitus),
limited range of motion, and muscle spasm.
 The onset of symptoms may be sudden or gradual, and symptoms may disappear
spontaneously, only to return in recurring cycles.
 Some studies report that the disease eventually “ burns out ” and symptoms
disappear or markedly decrease in severity in long-standing cases.

 Osseous changes in DJD are more accurately depicted in CT images, but
gross osseous changes may be evident in MRI studies.
 When the patient is in maximal intercuspation, the joint space may be
narrow or absent, which often correlates with an internal derangement
and frequently with a perforation of the disk or posterior attachment.
 Signs of previous remodeling, such as flattening and subchondral
sclerosis, may be evident, although degenerative changes may obscure
these findings.
 Loss of cortex or erosions of the articulating surfaces of the condyle or
temporal component (or both) are characteristic of this disease

 In some cases small, round, radiolucent areas with irregular margins surrounded
by a varying area of increased density are visible deep to the articulating surfaces.
 These lesions are called “ Ely ” or subchondral bone cysts but are not true cysts;
they are areas of degeneration that contain fibrous tissue, granulation tissue, and
osteoid
 Osteophytes may break off and lie free within the joint space “ joint mice”, and
these must be differentiated from other conditions that cause joint space
radiopacities
 Differential Diagnosis; substantial subchondral sclerosis and osteophyte formation
(proliferative component) to extensive erosions (degenerative component).

 Rheumatoid Arthritis; A more erosive appearance may simulate inflammatory
arthritides,
 Osteoma/ Osteochondroma; whereas a more proliferative appearance with
extensive osteophyte formation
 Treatment; directed toward relieving joint stress (e.g., splint therapy), relieving
secondary inflammation with anti-infl ammatory drugs, and increasing joint
mobility and function.

 Heterogeneous group of systemic disorders that manifests mainly as synovial
membrane inflammation in several joints.
 The TMJ becomes involved in approximately half of affected patients.
 The characteristic radiographic findings are a result of villous synovitis, which
leads to formation of synovial granulomatous tissue (pannus) that grows into
fibrocartilage and bone.
 More in females
 Increased incidence with increasing age
 TMJ involvement is usually bilateral and symmetric

 Usually the small joints of the hands, wrists, knees, and feet are affected in a
bilateral, symmetric fashion
 Patients with TMJ involvement complain of swelling, pain, tenderness, stiffness
on opening, limited range of motion, and crepitus.
 The initial changes may be generalized osteopenia (decreased density) of the
condyle and temporal component.
 Bone erosions by the pannus most often involve the articular eminence and the
anterior aspect of the condylar head
 Permits anterosuperior positioning of the condyle when the teeth are in maximal
intercuspation and results in an anterior open bite
 Sharpened Pincel

 Differential Diagnosis; severe DJD and psoriatic arthritis.
 Osteopenia and severe erosions, particularly of the articular eminence, are more
characteristic of RA.
 Psoriatic arthritis may be ruled out by the patient’s history.
 Treatment; Pain relief (analgesics), reduction or suppression of inflammation
(nonsteroidal anti-inflammatory drugs) and preservation of muscle and joint
functions (physiotherapy).
 Joint replacement surgery may be necessary in patients with severe joint
destruction.

 Juvenile rheumatoid arthritis, juvenile chronic arthritis, and Still ’ s disease
 Chronic inflammatory disease that appears before the age of 16 years (the mean
age is 5 years).
 It is characterized by chronic, intermittent synovial inflammation that results in
synovial hypertrophy, joint effusion, and swollen, painful joints.
 As the disease progresses, cartilage and bone are destroyed.
 Rheumatoid factor may be absent.
 JA differs from adult RA in that it has an earlier onset, and systemic involvement
usually is more severe.
 TMJ involvement occurs in approximately 40% of patients and may be unilateral
or bilateral.

 Severe TMJ involvement results in inhibition of mandibular growth.
 Patients may have micrognathia and posteroinferior chin rotation resulting in a facial
appearance known as “bird face” which may also be accompanied by an anterior open
bite.
 The degree of micrognathia is proportional to the severity of joint involvement and the
early onset of disease.
 When only one TMJ is involved or if one side is more severely affected, the patient
may have a mandibular asymmetry with the chin deviated to the affected side.

 Osteopenia (decreased density) of the affected TMJ components may be the only
initial radiographic finding.
 Radiographic findings are similar to those for the adult form except for the
addition of impaired mandibular growth.
 As a result of bone destruction, the condylar head typically is positioned
anterosuperiorly in the mandibular Fossa.
 Hypomobility at maximal opening is common, and fibrous Ankylosis may occur.

 Psoriatic arthritis and ankylosing spondylitis are seronegative, systemic arthritides
that may affect the TMJs.
 Psoriatic arthritis occurs in patients with psoriasis of the skin, with inflammatory
joint disease occurring in 7% of patients.
 Ankylosing spondylitis occurs predominantly in males, progressing to spinal fusion.
 TMJ radiographic changes seen in these disorders may be indistinguishable from
those caused by RA.
 Occasionally a profound sclerotic change is seen in psoriatic arthritis

 infection and inflammation of a joint that can result in joint destruction.
 It is rare in comparison to the incidence of DJD and RA in the TMJ.
 Septic arthritis may be caused by direct spread of organisms from an adjacent
cellulitis or from parotid, otic, or mastoid infections.
 May occur by direct extension of osteomyelitis of the mandibular body and ramus
or spread from a middle ear infection, although hematogenous spread from a
distant nidus has also been reported.
 RA, diabetes, immunosuppression, hypogammaglobulinemia, prolonged use of
systemic steroids, and sexually transmitted diseases.
 Has also been reported in children after blunt trauma, as a result of hyperemia
and increased exposure to microorganisms.

 It usually occurs unilaterally.
 The patient may have redness and swelling over the joint; trismus; severe pain on
opening; inability to occlude the teeth; large, tender cervical lymph nodes; fever;
and malaise.
 The mandible may be deviated to the unaffected side as a result of joint effusion.
 No radiographic signs may be present in early stages of the disease.
 The space between the condyle and the roof of the mandibular fossa may be
widened.
 Osteopenic (radiolucent) changes of the joint components and mandibular ramus
may be evident.
 More obvious bony changes are seen approximately 7 to 10 days after the onset of
clinical symptoms

 Differential Diagnosis
 The diagnosis of septic arthritis is ideally made by identification of organisms in joint
aspirate.
 Severe DJD or RA, although septic arthritis usually occurs unilaterally, and the
patient often has clinical signs and symptoms of infection.
 Inflammatory changes that may accompany septic arthritis may be seen in CT images,
such as involvement of mastoid.
 MRI T2
 Treatment; Antimicrobial therapy, drainage of effusion, and joint rest. Physiotherapy
to re-establish joint mobility is initiated after the acute phase of infection has passed

 Radiopacities of varying origin located in the synovium, within the capsule in the
joint spaces, or outside the capsule in soft tissue.
 They appear radiographically as soft tissue calcifications positioned around the
condylar head.
 The loose bodies may represent bone that has separated from joint components
 In DJD (joint mice), hyaline cartilage metaplasia that occurs in synovial
chondromatosis.
 Crystals deposited in the joint space in crystal-associated arthropathy
(pseudogout).

 Synovial chondrometaplasia and osteochondromatosis
 An uncommon disorder characterized by metaplastic formation of multiple
cartilaginous and osteo-cartilaginous nodules within connective tissue of the
synovial membrane of joints.
 Some of these nodules may detach and form loose bodies in the joint space,
where they persist and may increase in size, being nourished by synovial fluid.
 This condition is more common in the axial skeleton than in the TMJ.
 Synovial Osteochondromatosis; When the cartilaginous nodules ossify.
 Asymptomatic or may complain of preauricular swelling, pain, and decreased
range of motion. The condition usually occurs unilaterally.

 The joint space may be widened.
 Ossification of the cartilaginous nodules has occurred, a radiopaque mass or several
radiopaque loose bodies may be seen surrounding the condylar head.
 CT imaging can identify the location of the calcifications.
 Sclerosis of the glenoid fossa and condyle may be seen.
 Occasionally, erosion through the glenoid fossa into the middle cranial fossa may occur,
which is best detected with CT.
 MRI may be useful in defining the tissue planes between the synovial chondromatosis
mass and surrounding soft tissue.

 Synovial osteo chondromatosis cannot always be differentiated from
chondrocalcinosis; often the soft tissue calcifications in osteo chondromatosis are
larger and may have a peripheral cortex that identifies their bony nature.
 DJD with joint mice or chondrosarcoma or osteosarcoma; accompanied by severe
bone destruction,
 Treatment; removal of the loose bodies and resection of abnormal synovial tissue in
the joint by arthroscopic or open joint surgery.

 Pseudogout and calcium pyrophosphate dihydrate deposition disease
 Characterized by acute or chronic synovitis and precipitation of calcium
pyrophosphate dihydrate crystals in the joint space.
 It differs from gout, in which urate crystals are precipitated, pseudogout.
 The joints more commonly affected are the knee, wrist, hip, shoulder, and elbow;
 TMJ involvement is uncommon.
 The condition occurs unilaterally and is more common in males.
 Patients may be asymptomatic or may complain of pain and joint swelling.

 Differential Diagnosis; the same as for synovial chondromatosis.
 Treatment; surgical removal of the crystalline deposits.
 Steroids, aspirin, and nonsteroidal anti-inflammatory agents may provide relief.
 Colchicine may be used to alleviate acute symptoms and for prophylaxis.

 Influx of fluid into the joint, usually as a result of trauma (hemorrhage) or
inflammation (exudate).
 Inflammation may result from an internal derangement, traumatic injuries,
arthritis, or rheumatic diseases.
 The patient may have swelling over the affected joint; pain in the TMJ,
preauricular region, or ear; and limited range of motion.
 Patients may also complain of the sensation of fluid in the ear, tinnitus, hearing
difficulties, and difficulty occluding the posterior teeth.

 Joint effusion is more commonly seen in conjunction with internal derangements.
 The joint space is widened
 T2-weighted MRI studies may show a bright signal (white), indicating fluid
adjacent to the disk or posterior to the condyle
 Septic Arthritis; the accompanying signs and symptoms of infection are present.
 Treatment; may include anti-inflammatory drugs, although surgical drainage of
the effusion occasionally is necessary.

 Abnormal positioning of the condyle out of the mandibular fossa but within the
joint capsule.
 It usually occurs bilaterally and most commonly in an anterior direction.
 May be caused by a failure of muscular coordination, subluxation, or external
trauma and may be associated with a condylar fracture.
 In anterior dislocation, patients are unable to close the mandible to maximal
intercuspation; Pain and Spasm
 Some patients cannot reduce the dislocation, whereas others may be able to
reduce the mandible by manipulation.

 In bilateral cases both condyles are located anterior and superior to the summits
of the articular eminentia.
 Differential Diagnosis; confirmed by the radiographic findings, although
 CT or tomography is essential for diagnosis because routine plain film views may
not show the dislocation because of anatomic superimpositions.
 Treatment; manual manipulation of the mandible to reduce the dislocation

 Usually occur at the condylar neck and often are accompanied by dislocation of the
condylar head.
 Classified according to the anatomic location of the fracture: condylar head,
condylar neck, and subchondral region.
 Occasionally more than one anatomic location is involved.
 Unilateral fractures are more common, may be accompanied by a parasymphyseal
or mandibular body fracture on the contralateral side.
 The patient may have swelling over the TMJ, pain, limited range of motion, and
an anterior open bite.

 Some are relatively asymptomatic
 Condylar fractures should be ruled out if the patient has a history of a blow to the mandible,
especially to the anterior aspect.
 If a condylar fracture occurs during the period of mandibular growth, growth may be
inhibited because of damage to the condylar growth center.
 The degree of subsequent hypoplasia is related to the stage of mandibular development at
the time of injury and the severity of the injury.
 Younger patients have more profound hypoplasia

 Patients younger than 10 years old have a higher remodeling potential and may
have less deformity compared with older patients.
 Injuries in patients younger than 3 years old tend to produce severe asymmetries.
 Injury to the joint may result in hemorrhage or effusion into the joint spaces

 Recent condylar neck fracture; a radiolucent line limited to the outline of the neck is visible.
 May vary in width, depending on whether the bone fragments are still aligned (narrow line)
or displacement/dislocation has occurred.
 If the bone fragments overlap, an area of apparent increase in Radiopacity may be seen
 Approximately 60% of condylar fractures show evidence of fragment angulation and a
variable degree of displacement (dislocation) of the fracture ends.

 Fractures of the condylar head are less common and may be of the vertical
(responsible for the traumatic type of bifid condyle) or compressive type.
 CT is the preferred imaging modality to evaluate condylar fractures because there
is no superimposition.

 Developmental Anomaies
 Panoramic views taken as an initial examination must be supplemented with a
Towne’s view.
 Treatment; may not be indicated if mandibular mobility is adequate; otherwise,
the fracture is reduced surgically.

 The use of forceps during delivery of neonates may result in fracture and
displacement of the rudimentary condyle.
 Later manifests as severe mandibular hypoplasia and lack of development of the
glenoid fossa and articular eminence.
 Characteristic Radiographic Appearance; having the appearance of a partly
opened pair of scissors in place of a normal condyle
 Overlapping images of the medially displaced carrot-shaped condyle and
remnants of the condylar neck.

 Differential Diagnosis; often is not diagnosed until later in life.
 The condition must be differentiated from a developmental hypoplasia of the
mandible, which is unrelated to birth injury.
 Treatment; usually is not treated, but the mandibular asymmetry may be
corrected with a combination of orthodontics and orthognathic surgery

 Condition in which condylar movement is limited by a mechanical problem in the joint
(True) or by a mechanical cause not related to joint components (False).
 True Ankylosis may be bony or fibrous.
 In bony Ankylosis the condyle or ramus is attached to the temporal or zygomatic bone by an
osseous bridge.
 In fibrous Ankylosis a soft tissue union of joint components occurs.
 False ankylosis may result from conditions that inhibit condylar movement [muscle spasm,
myositis ossificans, or coronoid process hyperplasia.]

 Clinical Features
 Most unilateral cases are caused by mandibular trauma or infection.
 The most common cause of bilateral TMJ Ankylosis is rheumatoid arthritis.
 Most if not all cases of TMJ Ankylosis in infancy occur as a result of birth injury.
 Patients have a history of progressively restricted jaw opening.
 Some degree of mandibular opening usually is possible through flexing of the
mandible.

 In fibrous Ankylosis the articulating surfaces are usually irregular because of
erosions.
 The joint space is usually very narrow and the two irregular surfaces may appear
to fi t one another like a jigsaw puzzle.
 Little or no condylar movement is seen.
 Bony; Joint spaces are partially or completely obliterated
 Coronal CT images are the best diagnostic imaging method to evaluate Ankylosis.

 The major differential diagnosis is a condylar tumor.
 History of trauma, infection, or other joint diseases should help rule out neoplastic
disease.
 Treatment; Joint mobility is improved by surgical removal of the osseous bridge or
creation of a pseudarthrosis.

 Benign and malignant tumors originating in or involving the TMJ are rare.
 Tumors may be intrinsic or extrinsic (adjacent) to the TMJ.
 Intrinsic tumors may develop in the condyle, temporal bone, or coronoid process.
 Extrinsic tumors may affect the morphology, structure, or function of the joint
without invading the joint itself.
 They may cause indirect effects on growth, such as those seen with vascular
lesions or from pressure, or may influence mandibular positioning.

 The most common benign intrinsic tumors affecting the TMJ are osteomas,
osteochondromas, Langerhans histiocytosis, and osteoblastomas.
 Chondroblastomas, fibromyxomas, benign giant cell lesions, and aneurysmal bone
cysts also occur.
 Benign tumors and cysts of the mandible may involve the entire ramus
 In cases of false ankylosis in which the TMJs appear radiographically normal,
hyperplasia or a tumor of the coronoid process must be ruled out

 Condylar tumors grow slowly.
 Patients may complain of TMJ swelling, which may be accompanied by pain and decreased
range of motion; the symptoms often mimic TMJ dysfunction.
 The clinical examination may reveal facial asymmetry, malocclusion, and deviation of the
mandible to the unaffected side; these may be accompanied by symptoms of TMJ
dysfunction.
 Tumors of the coronoid process typically are painless, but patients may complain of
progressive limitation of motion.

 Condylar tumors cause condylar enlargement that often is irregular in outline.
 The trabecular pattern is altered, resulting in regions seen as radiolucencies or may
increase the Radiopacity of the condyle with abnormal trabeculae.
 An osteoma or osteochondroma appears as an abnormal, pedunculated mass attached to
the condyle
 Osteochondromas often extend from the anterior or superior surface of the condyle [Most
common Benign Tumor]

 Unilateral condylar hyperplasia, although osteomas and osteochondromas give an
irregular appearance, such as bulbous or globular expansion of the condyle or,
more commonly, a pedunculated growth.
 The characteristic condylar shape and proportions are better preserved in
condylar hyperplasia.
 Treatment; surgical excision of the tumor and occasionally excision of the condylar
head or coronoid process.

 May be primary or, more commonly, metastatic.
 Primary intrinsic malignant tumors of the condyle are extremely rare and include
chondrosarcoma, osteogenic sarcoma, synovial sarcoma, and fibrosarcoma of the
joint capsule.
 Extrinsic malignant tumors may represent direct extension of adjacent parotid
salivary gland malignancies, rhabdomyosarcoma (Children)
 The most common metastatic lesions include neoplasms originating in the breast,
kidney, lung, colon, prostate, and thyroid gland.

 May be asymptomatic or patients may have symptoms of TMJ dysfunction such as pain,
limited mandibular opening, mandibular deviation, and swelling.
 Unfortunately, a patient occasionally is treated for TMJ dysfunction without recognition
that the underlying condition is a malignancy.
 Appear as a variable degree of bone destruction with ill-defined, irregular margins.
 Most lack tumor bone formation, with the exception of osteogenic sarcoma.

 Chondrosarcoma may appear as an indistinct, radiolucent lesion of the condyle with
surrounding discrete soft tissue calcifications that may simulate the appearance of the
articular loose bodies seen in chondrocalcinosis or pseudogout.
 The radiographic appearance usually is nonspecific condylar destruction (exceptions, such
as metastatic prostate carcinoma) and does not indicate the site of origin
 CT is the imaging modality of choice to view bone involvement
 MRI is useful for displaying the extent of involvement into the surrounding soft tissues.

 Severe DJD; Malignant tumors cause profound central bone destruction, whereas
DJD causes more peripheral bone destruction.
 Proliferative changes such as osteophyte formation may be seen in DJD, but
unlike with a malignant tumor, no soft tissue mass or swelling is evident.
 Chondrosarcoma may simulate joint space calcifications
 Primary malignant tumors, treatment consists of wide surgical removal of the
tumor.
 Tumor extension to vital anatomic structures may compromise survival.
 Metastatic tumors of the TMJ rarely are treated surgically; treatment mainly is
palliative.

 Chapter 26: Diagnostic Imaging of the Temporomandibular Joint

Radiographic Features of Temporomandibular Joint and Disorders

Radiographic Features of Temporomandibular Joint and Disorders

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Radiographic Features of Temporomandibular Joint and Disorders

Similar to Radiographic Features of Temporomandibular Joint and Disorders (20)

More from Hadi Munib

More from Hadi Munib (20)

Recently uploaded

Recently uploaded (20)

Radiographic Features of Temporomandibular Joint and Disorders