Imaging of the Temporomandibular Joint &Pathology

Dr Sekhar

• Unique joint that it constitutes of two separate joints anatomically and they function together as a single unit

• Consists of: Condyles

Articular DiscMandibular Fossa

• Has a fibrous capsule that surrounds and encloses the joint

• 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

• MANDIBULAR FOSSA: Composed of the glenoid fossa and atricular eminence.

• INTERARTICULAR DISK: - Between condylar head and mandibular fossa - Biconcave shape

Disorders of the temporomandibular joint are abnormalities that interfere with the normal

form or function of the joint

Disorders of the Temporomandibular Joint1- Developmental Abnormalities

2- Soft Tissue Abnormalities

• Developmental Abnormalities:1- Condylar Hyperplasia2- Condylar Hypoplasia3- Juvenile Arthrosis 4- Coronoid Hyperplasia 5- Bifid Condyle

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

• 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

• Treatment: • Orthodontics combined with orthognathic

surgery

• 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

• 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

• 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

• 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

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

• - 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

• 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

• D/D: Vertical fracture through the condylar head

• Treatment: Not indicated unless pain or functional impairment is present

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

• 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.

• 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

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

• - 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)

• 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

• 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

• 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

• D/D: severe DJD and psoriatic arthritis and osteopenia

• Treatment:• - pain relief (analgesics)• - anti inflammatory drugs• - physiotherapy• - surgery (joint replacement)

• 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

• 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

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

• 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

• 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

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

• 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

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

• 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

Trauma1- 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

• Radiographic Features:- Commonly seen in conjunction with internal

derangements- Joint space is widened * D/D: septic arthritis* Treatment:- Anti-inflammatory drugs- Surgical drainage

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

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

• 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

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

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

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

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

* 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

2- Malignant Tumors:A- Primary (rare): - Intrinsic

- Extrinsic Intrinsic: Chondrosarcoma Osteogenic sarcoma

Senovial sarcoma Fibrosarcoma

Extrinsic: Direct extension of adjacent parotid salivary gland malignancies

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

Thank you