Anatomy of TMJ - Condyle - Glenoidfoss - Articular eminence - Interaraticular disk(Fibrous CT , divides joint cavity into two sup. and inf. )
CONDYLAR MOVMENT -Normal full jaw opening is 40-50 millimetres as measured from edge of lower front teeth to edge of upper front teeth - Condyle undergoes complex movment ( sliding downward and forward , rotation)
Diagnostic Imaging of the TMJ *OSSEOUS STRUCTURES *SOFT TISSUE STRUCTURES 1)Panoramic Projection 2)Plan film 3) Conventional Tomography 4) Computed Tomography 1) Arthrography 2) Magnetic Resonance Imaging(MRI)
OSSEOUS STRUCTURES :1)Panoramic Projection - limited quality. - only grossly osseous changes in condyle may be identified. - no info. about condyle position. 2)Plan film - multiple tichniques(transcranial,transpharyngeal,transorbital and submentovertex) malignant tumor
3) Conventional Tomography - multiple image at right angles. - showing condyler position and osseous changes. 4) Computed Tomography - can’t produce accurate images of the articular disk. - useful for ankylosis ,neoplasms ,complex fracture …. frontal sagittal
SOFT TISSUE STRUCTURES 1) Arthrography - indirect image of the disk is obtained by injecting a radiopaque contrast agent into the join spaces under fluoroscopic guidance 2) Magnetic Resonance Imaging(MRI) -MRI uses a magnetic field and radiofrequency pulses to produce multiple digital image slices - contraindicated in patients who are pregnant ,have pacemakers, intracranialvascular clips, or metal particles in vital structures disk disk
Abnormalities ofRadiographic the Temporomandibular Joint Articular Loose Bodies: 1)Synovial Chondromatosis 2)Chondrocalcinosis Trauma: 1)Effusion 2)Dislocation 3)Fracture 4)Neonatal Fractures 5)Ankylosis Tumors: 1)Benign Tumors 2)Malignant Tumors DEVELOPMENTAL ABNORMALITIES: 1)Condylar Hyperplasia 2)Condylar Hypoplasia 3)Juvenile Arthrosis 4)Coronoid Hyperplasia 5)Bifid Condyle SOFT TISSUE ABNORMALITIES: -Internal Derangement Remodeling and Arthritic Conditions: 1)Remodeling 2)Degenerative Joint Disease 3)Rheumatoid Arthritis 4)Juvenile Arthritis Psoriatic Arthritis and AnkylosingSpondylitis: -Septic Arthritis
DEVELOPMENTAL ABNORMALITIES 1)Condylar Hyperplasia: Definition: -developmental abnormality that results in enlargement and deformity of the condylar head. Clinical Features: -more common in males -usually is discovered before the age of 20 years -self-limiting and tends to arrest with termination of skeletal growth -mandibular asymmetry -chin may be deviated to the unaffected side -increase in the vertical dimension of the affected side -posterior open bite on the affected side -limited mandibular opening
Radiographic Features -Condyle enlarged ,altered in shape and more radiopaque -glenoidfossa may be enlarged -ramus and mandibular body on the affected side also may be enlarged Differential Diagnosis:osteochondroma Treatment :orthodontics combined with orthognathic surgery
2)Condylar Hypoplasia: Definition: -failure of the condyle to attain normal size Clinical Features: -mandibular growth deficiency -unilateral or bilateral -may be associated with congenital defects of the ear and zygomatic arch -mandibular asymmetry -chin commonly is deviated to the affected side Radiographic Features: - Small condyl and fossa -ramus and mandibular body on the affected side may also be small -mandibular asymmetry -condylar neck and coronoid process usually are very slender and are shortened
Differential Diagnosis:-juvenile rheumatoid arthritisTreatment :-Orthognathic surgery, bone grafts, and orthodontic therapy hypoplasia minimum involvement of the mandibularramus and body.
3)Juvenile Arthrosis: Definition: - condylar growth disturbance, manifests as hypoplasia but is thought to differ in that the affected condyle at one time was normal, becoming abnormal during growth. Clinical Features: -unilateral or bilateral -more common in females -may have mandibular asymmetry Radiographic Features: -“ toadstool ” appearance. - condylar neck is shortened or even absent in some -flattening and apparent elongation of the articulating condylar surface and dorsal (posterior) inclination of the condyle and neck
“ toadstool ” appearance Differential Diagnosis: - hypoplasia of the condyle Treatment : -Orthognathic surgery and orthodontic therapy
4)Coronoid Hyperplasia: Definition: -elongation of the coronoid process Two types: -Developmental usually bilateral -Acquired unilateral or bilateral Clinical Features: -Bilateral developmental coronoid hyperplasia is more common in males -inability to open the mouth. -painless. Radiographic Features: -coronoid processes are elongated -coronoid processes may impinge on the medial surface of the zygomatic arch during opening
impingement of hyperplasticcoronoid processes open mouth closed mouth Differential Diagnosis: -tumor of the coronoid (osteochondroma or osteoma). -ankylosis. Treatment : - surgical removal of the coronoid process and postoperative physiotherapy axial CT images
5)Bifid Condyle: Definition: -vertical depression, notch, or deep cleft in the center of the condylar head Clinical Features: -Rare -More often unilateral -Symptoms of temporomandibular dysfunction (joint noises and pain). Radiographic Features: -depression or notch is present on the superior condylar surface. -heart shape. Differential Diagnosis: -vertical fracture through the condylar head Treatment : -Treatment is not indicated unless pain or functional impairment is present
glenoidfossa has remodeled heartshape Coronal Sagittal
SOFT TISSUE ABNORMALITIES: -Internal Derangement: Definition: -abnormality in the position and sometimes the morphology of the articular disk that may interfere with normal function. Clinical Features: 1)Symptomatic or asymptomatic 2)Symptomatic patients may have a decreased range of mandibular motion 3)unilateral or bilateral Radiographic Features: MRI is the technique of choice The normal disk has a low signal intensity
Disk Displacement: -Anterior displacement is the most common -indication of anterior displacement is positioning of the posterior band forward so that it sits between the anterosuperior surface of the condyle and the eminence (hard to identify). posterior band anterior disk displacement NORMAL
Perforation and Deformities: -Perforations between the superior and inferior joint spaces -enlargement of the posterior band -may be increase the intensity Fibrous Adhesions and Effusion: -Fibrous adhesions: fibrous tissue or scar tissue that form in the joint space, particularly after TMJ surgery - Joint effusion: fluid in the joint
joint effusion Perforation
Tumors: 1)Benign Tumors The most common 1)Osteomas 2)Osteochondromas most common 3)Langerhanshistiocytosis 4)osteoblastomas Less common 1)Chondroblastomas 2)fibromyxomas 3)benign giant cell lesions 4)aneurysmal bone cysts
Clinical Features: 1)grow slowly 2)TMJ swelling 3)accompanied by pain 3)decreased range of motion 4)facial asymmetry 5)Malocclusion Radiographic Features: -Condylar tumorscondylar enlargement, irregular outline, trabecular pattern altered. -Osteoma or osteochondromaappears as an abnormal, pedunculated mass attached to the condyle. Differential Diagnosis: -condylar hyperplasia. -coronoid hyperplasia Treatment : -surgical excision of the tumor.
2)Malignant Tumors Primary: chondrosarcoma, osteogenic sarcoma, synovial sarcoma fibrosarcoma of the joint capsule Metastatic: originating in the breast, kidney, lung, colon, prostate, and thyroid gland.
Clinical Features: -asymptomatic or patients may have symptoms of TMJ dysfunction such as pain, limited mandibular opening, mandibular deviation, and swelling. Radiographic Features: -Variable degree of bone destruction with ill-defined, irregular margins. - CT view bone involvement. - MRI view soft tissues involvement. Differential Diagnosis: -severe Degenerative Joint Disease. Treatment : -primary Wide surgical removal of the tumor. -Metastatic palliative , radiotherapy and chemotherapy
radiopacities (soft tissue calcifications) radiolucent destructive lesion in condylar head Chondrosarcoma
Remodeling and Artritis conditions :1)Remodeling Definition: 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. :Clinical Features -may be asymptomatic. -or patients may have signs and symptoms of temporomandibular dysfunction. -internal derangement of the disk. :Radiographic Features -changes may affect the condyle, temporal component,or both. -The radiographic appearance may include one or a combination of the following: *flattening *cortical thickening of articulating surfaces *subchondralsclerosis
Subchondral sclerosis & flattening sagittal coronal Differential Diagnosis:degenerative joint disease. Treatment: -No clinical signs or symptoms are presents >>> no treatment indicated -Stress on the joint>>>treatment indicated ( splint therapy ).
2)Degenerative joint disease (Osteoargitis) :Definition (DJD) is a non-inflammatory disorder of joints characterized by 1-joint deterioration: loss of the articular cartilage and bone erosion>>>more common in acute disease 2-proliferation: new bone formation at the articular surface and in the subchondral region>>>in chronic disease. - etiology is unknown. - factors may be important, including acute trauma, hypermobility, and loading of the joint. Clinical features: - occur at any age. - female preponderance. - The disease may be asymptomatic, or patients may complain of signs and symptoms of TMJ dysfunction. -The onset of symptoms may be sudden or gradual, and symptoms may disappear spontaneously
Radiographic Features: -Loss of cortex or erosions of the articulating surfaces of the condyle or temporal component (or both). -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 >>> called “Ely ” or subchondral bone cysts>>> they are areas of degeneration. Ely cyst Thin joint space
-Later in the course of the disease, bony proliferation occurs at the periphery of the articulating surface, increasing the articulating surface area. This new bone is called an osteophyte. flattening osteophyte Joint mouse erosions
Differential Diagnosis: -rheumatoid arthritis -osteoma -osteochondroma Treatment: -relieving joint stress (splint therapy), -relieving secondary inflammation with anti-inflammatory drugs, -And increasing joint mobility and function (physiotherapy).
(RA)3)Rheumatoid Arthritis :Definition (RA) is a 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. Clinical Features: -common in females and can occur at any age. -Usually the small joints of the hands, wrists, knees, and feet. -The chin appears receded(anterior open bite). -TMJ involvement usually is bilateral and symmetric. Radiographic Features -generalized osteopenia>> initial changes. -Bone erosions by the pannus involve the articular eminence and the anterior aspect of the condylar >>>anterior open bite -Subchondral sclerosis and flattening of articulating surfaces,subchondral “ cyst ” and osteophyte formation. -Fibrous ankylosis or osseous ankylosis, may occur.
Sharpedpencile appearance Open bite Irregular surface of the condyle &articular eminence >fibrous ankylosis
Differential Diagnosis: -severe DJD Psoriatic arthritis(may be ruled out by the patient’s history). :Treatment -pain relief (analgesics) -reduction or suppression of inflammation (non-steroidal anti-inflammatory drugs, gold salts, corticosteroids) -preservation of muscle and joint function (physiotherapy). -Joint replacement surgery may be necessary in patients with severe joint destruction.
4)Juvenile Arthritis(Still’s disease) Definition: is a 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. -TMJ involvement occurs in approximately 40% of patients and may be unilateral or bilateral. :Clinical Features -pain and tenderness in the affected joint or joints. -can be asymptomatic. -Unilateral onset is common, but contra-lateral involvement may occur as the disease progresses. -Severe TMJ involvement results in inhibition of mandibular growth. -Affected patients may have micrognathia and posteroinferior chin rotation>> “bird face,” which may also be accompanied by an anterior open bite.
:Radiographic Features -Osteopenia of the affected TMJ components may be the only initial radiographic finding. -findings are similar to those for the adult form except for the addition of impaired mandibular growth. ***Manifestations of inhibited mandibular growth, such as deepening of the antegonial notch, diminished height of the ramus, and dorsal bending of the ramus and condylar neck, also may occur unilaterally or bilaterally>>>obtuse angle -Erosions may extend to the mandibular fossa, and the articular eminence may be destroyed. -As a result of bone destruction, the condylar head typically is positioned anterosuperiorly in the mandibular fossa Erosin of eminence
-Erosions may extend to the mandibularfossa, and the articular eminence may be destroyed. Oblique-sagittal image shows wide flat fossa and condyle, with sclerosis
Psoriatic Arthritis and AnkylosingSpondylitisSeptic Arthritis Definition: Septic arthritis is infection and inflammation of a joint that can result in joint destruction. :Clinical Features -any age, no sex predilection. -It usually occurs unilaterally. -The mandible may be deviated to the unaffected side as a result of joint effusion. :Radiographic Features -No radiographic signs may be present in early stages of the disease. -Osteopenic changes (joint and ramus ). -More obvious bony changes are seen approximately 7 to 10 days after the onset of clinical.S. -As a result of the osteolytic effects of inflammation, the condylar articular cortex may become slightly radiolucent, erosions of the surface of the condyle and articular eminence may be seen, sequestra may become apparent, and there may be periosteal new bone formation. :Differential Diagnosis Inflammatory changes may be seen in 1)CT images, such as involvement of mastoidair cells, osteomyelitis of the mandible, and inflammation of surrounding soft tissue. .2) MRI, muscle enlargement, joint effusion, or abscess
Treatment -antimicrobial therapy, -drainage of effusion -joint rest. - Physiotherapy to re-establish joint mobility is initiated after the acute phase of infection has passed coronal Erosions, sclerosis & periosteal reaction extend along back and lateral neck of the condyle sagittal Axial
Articular Loose Bodies1) Synovial ChondromatosisSynovial chondrometaplasia ,Osteochondromatosis :Definition uncommon disorder characterized by metaplastic formation of multiple cartilaginous and osteocartilaginous nodules within connective tissue of the synovial membrane of joints. Clinical Features - may be asymptomatic -may complain of preauricular swelling, pain, and decreased range of motion and joint noises. • -usually unilaterally. • Radiographic Features: -The joint space may be widened, and if ossification of the cartilaginous nodules has occurred, a radiopaque mass or several radiopaque loose bodies may be seen surrounding the condylar head. -Sclerosis of the glenoidfossa and condyle may be seen. -erosion through the glenoidfossa into the middle cranial fossa may occur>>CT
panoramic Differential Diagnosis: -DJD with joint mice -chondrosarcoma -osteosarcoma. :Treatment removal of the loose bodies and resection of abnormal synovial tissue in the joint by arthroscopic or open joint surgery. Axial CT image multiple ossified bodies surrounding the condyle and within the joint capsule.
2)Chondrocalcinosis“Pseudogout and calcium pyrophosphate dihydrate deposition disease” :Definition Chondrocalcinosis is characterized by acute or chronic synovitis and precipitation of calcium pyrophosphate dihydrate crystals in the joint space. Clinical Features: -TMJ involvement is uncommon. -occurs unilaterally ,,more common in males. -asymptomatic or may complain of pain and joint swelling. Radiographic Features: • -Often the radiopacities within the joint space are finer and have a more even distribution than in osteochondromatosis. -Bone erosions and a severe increase in condylar bone density. -Erosion of the glenoidfossa may be present. -Soft tissue swelling and edema of the surrounding muscles.