This document summarizes diagnostic imaging techniques for disorders of the temporomandibular joint (TMJ). It describes the anatomy of the TMJ and its components. It then discusses various disorders including developmental abnormalities like condylar hyperplasia and hypoplasia, soft tissue abnormalities like internal derangements, remodeling and different types of arthritis. It also covers trauma-related conditions, tumors, and diagnostic features seen on imaging for each disorder. A wide range of TMJ pathologies are described with an emphasis on radiographic presentations.

1. Diagnostic Imaging of the
Temporomandibular Joint
Fares H. Hanafieh & Fahad F. Salehi

2.  What is the Temporomandibular joint?
 Unique in that it constitutes of two separate joints
anatomically and they function together as a single unit
 Consists of: Condyles
Articular Disc
Mandibular Fossa
 Has a fibrous capsule that surrounds and encloses the
joint

3.  CONDYLE:
- Shape of condyle varies considerably
- Superior aspect maybe flattened,
rounded or markedly convex
- Mediolateral contour is usually slightly
convex
- Variations in shape may cause difficulty
with radiographic interpretation
- Extreme aspects of the condyle are the medial
pole and lateral pole

4.  MANDIBULAR FOSSA: Composed of the glenoid fossa and atricular eminence.
 INTERARTICULAR DISK: - Between condylar head and
mandibular fossa
- Biconcave shape

5. Disorders of the temporomandibular joint are
abnormalities that interfere with the normal form or
function of the joint

6. Disorders of the
Temporomandibular Joint
1- Developmental Abnormalities
2- Soft Tissue Abnormalities

7.  Developmental Abnormalities:
1- Condylar Hyperplasia
2- Condylar Hypoplasia
3- Juvenile Arthrosis
4- Coronoid Hyperplasia
5- Bifid Condyle

8. 1- Condylar Hyperplasia:
- Enlargement and deformity of the condylar head
- Secondary effect on the mandibular fossa as it remodels to
accommodate the abnormal condyle
Etiology: Trauma, infection, hereditary
 More common in males
 Self limiting
 Progresses slowly or rapidly
 Mandibular asymmetry
 Chin deviated to the affected side

9.  Radiographic Features:
 May appear normal but symmetrically enlarged
 Maybe more radiopaque due to additional bone present
 Condylar neck may be elongated
 Glenoid fossa may also be enlarged
 Ramus and mandibular body on the affected side also may be enlarged, resulting in a
characteristic depression of the inferior mandibular border
 The affected ramus may have increased vertical depth and may be thicker in the
anteroposterior dimension
 D/D: - Osteochondroma
- Condylar osteoma or osteophyte that occurs in chronic degenerative joint disease

10.  Treatment:
 Orthodontics combined with orthognathic surgery

11.  2- Condylar Hypoplasia
 Failure of the condyle to attain normal size because of
congenital and developmental abnormalities or acquired
diseases that affect condylar growth.
 The condyle is small, but condylar morphology is normal
 Underdeveloped ramus and occasionally mandibular
body
 Unilateral or bilateral

12.  Radiographic Features:
 The condylar neck and coronoid process usually are very slender
and are shortened or elongated in some cases
 The ramus and mandibular body on the affected side may also be
small, resulting in a mandibular asymmetry and occasional
dental crowding, depending on the severity of mandibular
underdevelopment
 D/D: Juvenile rheumatoid arthritis and arthritic conditions
 Treatment: orthognathic surgery
bone grafts
orthodontic therapy maybe required

13.  3- Juvenile Arthrosis:
 Manifests as hypoplasia and characteristic morphologic
abnormalities
 May be a form of condylar hypoplasia
 It affects children and adolescents during the of
mandibular growth
 More common in females
 Incidental finding in a panoramic projection

14.  Radiographic appearance:
 Condylar head develops a characteristic “toadstool” appearance
 Condylar neck is shortened or even absent in some cases
 D/D: developmental hypoplasia
rheumatoid arthritis
* Treatment: orthrognathic surgery
orthodontic therapy

15.  4- Coronoid Hyperplasia:
 - acquired or developmental
 - elongation of the coronoid process
 - developmental -> bilateral
 acquired -> uni or bilateral
 - inability to open mouth
 - painless

16.  - Radiographic features:
 Best seen in panoramic,
Waters, and lateral tomographic views and on CT scans
 TMJs usually appear normal
 -D/D: Unilateral cases should be differentiated from a tumor of the
coronoid process (osteochondroma or osteoma)
 Unlike coronoid hyperplasia, tumors have an irregular shape
 -Treatment: surgical removal or the coronoid process and postoperative
physiotherapy

17.  5- Bifid Condyle:
 Vertical depression,
notch, or deep cleft
in the center of the condylar head
 Rare, often unilateral
 Incidental finding
 Some patients may have sings of TMDs (noises + pain)
 Radiographic Features:
 Depression on the superior condylar surface giving a heart shape

18.  D/D: Vertical fracture through the condylar head
 Treatment: Not indicated unless pain or functional
impairment is present

19. Soft Tissue Abnormalities
 Internal Derangements - abnormality in the articular disc and
may interfere with normal function
 - Cause is unknown
 - Internal derangements can be diagnosed by MRI
 Clinical Features:
 - found in both symptomatic and healthy pts
 - symptomatic pts may have a decreased range of mandibular
motion
 -displacements may be unilateral or bilateral

21.  Radiographic Features:
 - MRI is the technique of choice
 Disc Displacement:
 - Anterior displacement is most common
 - The articular disc is located anterior to the condylar head
 Disk reduction and nonreduction:
 - reduction is when an anteriorly displaced disk may reduce to a normal
relationship with the condylar head during any part of the mouth
opening movement
 - nonreduction is when the disk remains anteriorly displaced and will
undergo permanent deformation.

22.  Perforation and Deformities:
 - perforations between the superior and inferior joint spaces
most commonly occur in the retrodiskal tissue, just behind the
posterior band of the disk
 - Not reliably detected with MRI
 Fibrous Adhesions and Effusion:
 - Fibrous adhesions are masses of fibrous or scarred tissue that
form in the joint space, particularly after TMJ surgery
 - Joint Effusion means fluid in the joint and is considered to be
and early change that may precede degenerative joint disease
 - Both can be detected by MRI

23. Remodeling and Arthritic conditions
 1- Remodeling:
 - Adaptive response of cartilage and osseous tissue to forces
applied to the joint that maybe excessive, resulting in
alteration of the shape of the condyle and articular eminence
 - no destruction or degeneration of articular soft tissue occurs
 - occurs throughout adult life
 - considered abnormal only if it is accompanied by clinical
signs and symptoms of pain or dysfunction

24.  - Radiographic Features:
 - flattening
 - cortical thickening of articulating surfaces
 - subchondral sclerosis
 -D/D: flattening and subchondral sclerosis maybe difficult to
differentiate from early degenerative joint disease
 - Treatment:
 - Only indicated when signs and symptoms are present. (ex. Splint
therapy)

25.  2- Degenerative joint disease (osteoarthritis):
 - non inflammatory disorder of the
joints characterized by
joint deterioration and proliferation
 - can occur at any age (incidence increases with age)
 - female predominance
 - asymptomatic or pts may complain of signs + symptoms of TMJ dysfunction
 - Radiographic features:
 - more accurately seen in CT but gross osseous changes maybe evident in MRI studies
 At the maximum intercuspation joint space may be narrow or absent
 Loss of cortex or erosions of the articulating surfaces of the condyle or temporal
component are characteristics of this disease

26.  D/D:
 - Erosive appearance  inflammatory arthritides (rheumatoid
arthritis)
 - Proliferative appearance with extensive osteophyte
formation  benign tumor  osteoma or osteochondroma
 Treatment:
 - Relieving joint stress (e.g. Splint therapy)
 - relieving secondary inflammation with anti-inflammatory
drugs
 - Increasing joint mobility and function  physiotherapy

27.  3- Rheumatoid Arthritis:
 - Synovial membrane inflammation
 - Patients with TMJ involvement complain of swelling, pain,
tenderness, stiffness on opening, limited range or motion, and
crepitus
 - Radiographic Features:
 - Osteopenia (decreased density) of the condyle and temporal
component
 - erosion of anterior and posterior condylar surfaces
 if erosion is severe  condylar head is destroyed

28.  D/D: severe DJD and psoriatic arthritis and osteopenia
 Treatment:
 - pain relief (analgesics)
 - anti inflammatory drugs
 - physiotherapy
 - surgery (joint replacement)

29.  4- Juvenile Arthritis:
 - Inflammatory disease that is characterized by chronic, intermittent
synovial inflammation
 - results in: synovial hypertrophy, joint effusion, and swollen, painful
joints
 -pain and tenderness of affected joint or joints
 - can be asymptomatic
 - unilateral is common
 - facial appearance known as “bird face”
 - possible mandibular asymmetry if one side is more severely affected

30.  Radiographic features:
 - Osteopenia (decreased density) maybe only an initial
radiographic finding
 - Impaired mandibular growth
 - Severe cases: only pencil shaped small condyle
remains
 - Abnormal disk shape is often observed in patients with
TMJ involvement

31. Psoriatic Arthritis and
Akylosing Spondylitis
Septic Arthritis: Infection and inflammation of a joint that can result in joint
destruction
- Affects any age
- No sex predilection
- Occurs unilaterally
- Redness and swelling over joint
- Trismus
- Severe pain on opening
- Inability to occlude the teeth
- Large, tender cervical lymph nodes
- Fever and malaise

32.  Radiographic Features:
- No radiographic signs may be present in early stages of
the disease
- Osteopenic (radiolucent) changes of the joint
components and mandibular ramus may be evident (7-10
days after onset of clinical symptoms)
- Osseous ankylosis may occur after infection subsides

33.  D/D: radiographic changes caused by septic arthritis
may mimic those of severe DJD or RA
 Treatment:
- Antimicrobial therapy
- Drainage of effusion and joint rest
- Physiotherapy

34. Articular Loose Bodies
- Radiopacities of varying origin located in the joint synoviom, within the
capsule in the joint spaces, or outside in soft tissue
1- Synovial Chondromatosis:
- Uncommon disorder characterized by metaplastic formation of multiple
cartilaginous and osteocartilaginous nodules within connective tissue of the
synovial membrane of joint
- Asymptomatic
- May complain of preauricular swelling, pain, and decreased range of motion
- Some patients have crepitus or other joint noises

35.  Radiographic Features:
- Osseous components may appear normal or may exhibit
osseous changes similar to those in DJD
- Sclerosis of glenoid fossa and condyle may be seen (chronic
bone reaction to an active lesion)
- MRI may be useful in defining the tissue planes between the
synovial chondromatosis and surrounding soft tissue
* D/D: DJD with joint mice or chondrosarcoma or osteosarcoma
* Treatment: Arthroscopic or open joint surgery  remove loose
bodies and resection of abnormal synovial tissue

36. 2- Chondrocalcinosis:
- Characterized by acute or chronic synovitis and
precipitation of calcium pyrophosphate dihydrate
crystals in the joint space
- Most commonly affected joints are knee, wrist,
shoulder, and elbow
- TMJ involvement uncommon
- Unilaterally and more common in males
- Asymptomatic or complaints of pain and joint swellings

37.  Radiographic Features:
- May simulate synovial chondromatosis
- Bone erosions and severe increase in condylar bone density
- Erosions of the glenoid fossa may be present (detected with CT)
- Soft tissue swelling and edema of the surrounding muscles may be seen with MRI
* D/D: DJD with joint mince or chondrosarcoma or osteosarcoma
* Treatment:
- Surgical removal of crystalline deposits
- Steroids, aspirin, and non steroidal anti inflammatory agents may provide relief

38. Trauma
1- Effusion:
- Influx of fluid into the joint as a result of trauma
(hemorrhage or inflammation)
- Swelling over affected joint
- Pain in TMJ, preauricular region, and limited range of
motion

39.  Radiographic Features:
- Commonly seen in conjunction with internal
derangements
- Joint space is widened
* D/D: septic arthritis
* Treatment:
- Anti-inflammatory drugs
- Surgical drainage

40. 2- Dislocation:
- Abnormal positioning of the condyle out of the mandibular fossa
but within the joint capsule
- Unable to close mandible to maximal intercuspation
* Radiographic Features:
- In bilateral cases, both condyles are located anterior and
superior to summits of articular eminentia
* Treatment:
- Manual manipulation to reduce the dislocation
- Surgery in the case of fracture dislocation

41. 3- Fracture:
- Usually occur at condylar neck and often are
accompanied by dislocation of the condylar head
- Unilateral fractures more common
- May be accompanied by parasymphyseal or mandibular
body fracture on contralateral side
- Swelling over TMJ
- Limited range of motion

42.  Radiographic features:
- Radiolucent line limited to the outline of the neck is
visible
- If bone fragments overlap, an area of increase in
radiopacity may be seen
* D/D: Town’s view panorama is taken to view fractures
* Treatment: Reduced surgically

43. 4- Neonatal Fracture:
- Use of forceps during delivery of neonates may result in
fracture and displacement of the rudimentary condyle
- Severe mandibular hypoplasia
* D/D: Developmental hypoplasia
* Treatment: Combination of orthodontic and
orthognathic surgery

44. 5- Akylosis:
- Condition in which condylar movement is limited by a mechanical problem in
the joint or by a cause not related to joint components
- Restricted jaw opening or limited jaw opening
* Radiographic Features:
- In fibrous ankylosis articulating surfaces are usually irregular because of
erosions
- In bony ankylosis joint space may be partly or completely obliterated by the
osseous bridge
- Coronal CT images are the best
to evaluate ankylosis
* D/D: Condylar Tumor
* Treatment:
- Surgical removal of osseous bridge
- Creation of pseudoarthrosis

45. Tumors
- Intrinsic or extrinsic
- Intrinsic develop in condyle, temporal bone or coronoid
process
- Extrinsic tumor may affect the morphology, structure
and function of the joint without invading the joint
itself

46. 1- Benign Tumors:
- Osteoma, osteochondroma, Langerhans histocytosis and osteoblastomas
- Chondroblastomas, fibromyxomas, benign giant cell lesions and
anneurysmal bone cysts also occur
- Benign tumors and cysts of the mandible may involve the entire ramus
and condyle
- Grow slowly
- TMJ swelling
- Pain and decrease in range of motion
- Tumors of coronoid process are painless but may complain of progressive
limitation of motion

47. * Radiographic Features:
- Condylar tumors  condylar enlargement with irregular
outline
- Osteoma and osteochondroma appear as abnormal,
pedunculated mass attached to the condyle
* D/D: Condylar neoplasms may simulate condylar
hyperplasia because of condylar enlargement although it
might be irregular in appearance
* Treatment: Surgical excision of tumor and occasionally
excision of condylar head or coronoid process

49. 2- Malignant Tumors:
A- Primary (rare): - Intrinsic
- Extrinsic
Intrinsic: Chondrosarcoma
Osteogenic sarcoma
Senovial sarcoma
Fibrosarcoma
Extrinsic: Direct extension of adjacent parotid salivary gland
malignancies

51. B- Metastatic (more common)
- May be asymptomatic or patients may have symptoms of TMJ dysfunction
(pain, limited mandibular opening, mandibular deviation and swelling)
* Radiographic Features:
- Variant degree of bone destruction with ill defined, irregular margins
- CT modality of choice
- MRI useful for displaying extent of involvement into surrounding tissues
* D/D: Osseous destruction of bone seen in severe DJD
* Treatment:
- Wide surgical removal of tumor
- May include radiotherapy and chemotherapy

52. Thank you