Download Temporomandibular Joint (TMJ)

Temporomandibular Joint (TMJ)
This joint represents the complex "articulation" between the moveable mandible and the base
of the skull.
Specific articulation movements actually take place in 2 regions:
1) between the mandibular and maxillary dentition - termed interjaw dental occlusion
2) between the head of the mandibular condyle and glenoid fossa of temporal bone.
 Condylar process
 lined by fibrous tissues, primarily hyaline cartilage
 this is the primary growth center of the mandible
• damage leads to facial maldevelopment, including both the mandible
and the maxilla
 Coronoid process
 insertion for portions of temporalis and masseter
The TMJ is a condylar synovial type of joint. The specific definition of this joint type
describes two opposing surfaces both of which display two convex and two concave
surfaces.
The movements and structure of the TMJ should always be considered as a pair i.e. one
condyle is the left TMJ while the other condyle is the right TMJ.
The articular surfaces are covered by cartilage. In addition an articular disc divides the joint
into two. Around the joint is the articular capsule which, in certain regions is thickened to
form "ligaments" which are given specific names.
 5 ligaments assoc. with TMJ
 3 functional, 2 accessory
 functional:
 collateral (discal) ligaments
 capsular ligament
 temporomandibular ligament
 accessory:
 sphenomandibular
 stylomandibular
1) Temporomandibular ligament.
2) Sphenomandibular ligament.
3) Stylomandibular ligament.
Note that, due to the disc the joint is divided into superior and inferior compartments.
Movements of mandible
1.Protraction: While maintaining the teeth in the occlusal position - slide the mandible
anteriorly.
2) Retruction: Slide the mandible posteriorly after protrusion. Confirm that the condyle
moves up as it reaches the fossa.
3) Depression: Note that 2 phases of depression occur. An initial opening and rotation
followed by a gliding.
4) Elevation: The opposite to depression.
5) Lateral excursions: This movement occurs when the teeth slide from the centic position to
the right or left, while maintaining occlusal contact, then back to the centric position.
Diseases of theTMJ
 The TMJ is susceptible to all diseases that affect other joints
1. congenital anomalies
2. ankylosis
3. arthritis
4. trauma
5. dislocations
6. neoplasms
Disorders of theTMJ
 Muscle Disorders
(Extracapsular)
 TMJ Disorders
(Intracapsular)
1.Inflammatory conditions
2.Internal derangement
 Disc sticking
 TMJ dislocation
 Disc displacement with reduction
 Disc displacement without reduction
Diagnosis of myofacial pain
 The temporomandibular joint and preauricular area is tender to palpation,
manipulation, and/or vertical loading.
 Patient generally reports pain with mandibular function.
Myofascial Pain Disorders
 Categories:
1. Myositis
2. Muscle Spasm
3. Contracture
4. Hysterical trismus
5. Fibromyalgia
TMJ Dislocation
An anatomical relationship in which the lateral pterygoid muscle advances the condyle
anterior and superior to the crest of the articular eminence, and due to muscle spasm in
the elevator muscles and/or specific anatomical relationships, the patient is unable to
return to a closed position.
 Acute dislocation
 treatment is reduction under anesthesia
 Chronic dislocation
 usually secondary to abnormally lax tendons
 Treatment: sclerosing agents, capsulorraphy, myotomy of lateral pterygoid
Treatment of Mandibular Dislocation
Therapy for Temporomandibular Disorders
Occlusal appliances - Stabilization splints
 Fills in interocclusal space if bite is unsupported or
unstable (e.g. posterior open bites )
 Disengages occlusal habits (can be a full occlusal
coverage appliance, or a partial occlusal coverage
applicable but this should be worn only short term to
avoid inducing an occlusal change)
 May interrupt bruxing habits
 May reduce direct joint loading
 May indirectly reduce joint loading by reducing jaw
muscle hyperfunction / clenching
Surgery of TMJ
 Less than 1% of people with TMJ symptoms will require surgery
 Five requirements for surgery
Kinds of sugery
 Disc Repair
 Menisectomy
 Menisectomy with implantation
 Arthroscopy
Radiology
 MRI is best technique for joint space pathology
 CT is best technique for bony pathology
 Plain films with arthrography sometimes useful, although largely replaced by MRI and
CT
 Arthroscopy is also diagnostic