Univ.-Prof. Dr. Dr. Gerhard Undt
Specialist for TMJ (temporomandibular joint) disorders, TMD, facial pain and salivary gland diseases

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Glossary TMJ disorders





Acute TMJ pain
Acute TMJ pain can be attributed to a variety of factors: trismus (locked jaw) caused by disc displacement, TMJ inflammation or TMJ arthritis (mono-arthritis of the TMJ caused by chlamydia, polyarthritis or psoriatic arthritis with acute involvement of the TMJ) or pain actually emanating from other structures (such as the masticatory muscles) that is projected into the TMJ.

The severing of adhesions in the TMJ.

Adhesions in the TMJ
Formation of fibrous bands within the joint space which limit movements of the mandibular condyle.

Analogue terms for TMJ in different languages

Arabic المشتركة  
Bulgarian темпоромандибуларната става   
Chinese 總搜尋網頁      是以颞颌关节  
Czech Temporomandibulárního kloubu TMK
Danish Kæbeled   
Dutch Kaakgewricht  
English Temporomandibular joint TMJ
Finnish  Leukanivel   
French Articulation temporo-mandibulaire ATM
German Kiefergelenk  
Greek κροταφογναθική διάρθωση  
Hebrew מפרק לסתי-רקתי   
Hungarian Állkapocs izület  
Indonesian Sendi rahang  
Italian Articolazione temporo mandibolare ATM
Japanese 顎関節   
Latin Articulatio temporo-mandibularis  
Norwegian Kjeveledd  
Polish Stawu skroniowo-zuchwowego  
Portuguese Articulação temporomandibular ATM
Rumanian Articulatie temporomandibulara  
Russian височно-нижнечелюстной сустав ВНЧС
Serbian Temporomandibularnog zgloba  
Slovakian čeľustného kĺbu  
Slovenian Spodnja čeljust (senčnico in manidibulo)  
Spanish Articulación temporomandibular  ATM
Swedish Käkleden  
Turkish Temporomandibular Eklem TME

Ankylosis of the TMJ
Severely restricted movement of the joint due to increasing ossification. We differentiate between fibrous and bony ankylosis of the TMJ. The transition from fibrous to bony ankylosis is gradual and difficult to clearly define.

Joint pain.

This actually means joint puncture or aspiration.

Joint disease.

Articular disc
The articular disc is an oval plate of fibrous tissue, which divides the temporomandibular joint into an upper and a lower joint compartment. It compensates the shape of the non-congruent bony joint surfaces during movements and distributes the load during chewing, biting and grinding. We find similar viscoelastic pads in the knee and in the shoulder joint. Top

Bilaminar region
The bilaminar zone of the TMJ is located posterior to the articular disc. Two ligaments connect the disc to the temporal bone and to the mandibular condyle. They are separated by a venous plexus (Zenker’s retrodiscal cushion). The upper ligament, which attaches to the fossa’s posterior margin, is composed of fibroelastic tissue, whereas the lower ligament, which is composed of  non-elastic fibrous tissue, attaches to the back of the mandibular condyle.

Muscle tension, sweat gland activity, heart rate and other parameters are measured, conveying the information to the patient in real-time. The patient learns how to gain control of functions like tension of the chewing muscles or general muscle tone. See conservative therapy of temporomandibular disorders.

Grinding the teeth. Top

Capsular fibrosis of the TMJ
Long-term inflammation of the synovial membrane of the TMJ can lead to inflammation of the joint capsule and to fibrosis. This restricts the mobility of the TMJ

Capsulitis of the TMJ
Inflammation of the joint capsule.

Chronic TMJ pain
This can have a variety of causes: chronic trismus (locked jaw) caused by disc displacement, TMJ inflamation or TMJ arthritis (primary chronic polyarthritis, juvenile polyarthritis or psoriasis-arthritis involving the TMJ) or pain actually emanating from other structures (such as the masticatory muscles) that is projected into the TMJ.

A parafunctional activity of the jaws that occurs mostly during daytime.

Cranio- mandibular dysfunction.

The function of the Cranio-mandibular or masticatory system is complex. It is composed of the organs of the head and neck: The bony structures of the facial skeleton including the teeth, the chewing muscles, the muscles of the neck and the shoulders and of the nervous structures connecting them to the central nervous system.

Contusion of the TMJ
An impact to the lower jaw can injure the soft tissue of the TMJ. This result in joint effusion or bleeding in the TMJ. The teeth on the side of the affected TMJ cannot completely come together. An x-ray should always be taken to rule out a condylar fracture.

Costen syndrome
This is not a term that is generally used nowadays. It was originally used to refer to the combination of a wide range of symptoms such as vertigo, earache, impaired hearing,  tinnitus, pain in the temporomandibular joint, pain in the masticatory muscles, a burning sensation of the tongue, to name but a few. We now refer to this as TMD or myofacial dysfunction.

Cystic lesions of the TMJ
These occur in association with TMJ arthroses. They can be present in the condyle or the articular eminence (part of the socket). Regular MRI scans are necessary to check if the cysts have grown.

The knuckle or condyloid process of the mandible.

Grating sound caused by rough joint surfaces. Top

Cutting and coagulating tissue with electrical current. Both bipolar and monopolar diathermy is used in the temporomandibular joint.

Disc displacement in the TMJ
The articular disc of the temporomandibular joint is displaced from its normal position. We distinguish between the following directions of disc displacement:

     Anterior disc displacement
     Posterior disc displacement
     Medial disc displacement
     Lateral disc displacement

We describe the grade of disc displacement:

     Partial disc displacement
     Total disc displacement

And we describe the position of the disc in relation to the condyle when the mouth is open:

     Disc displacement with reduction
     Disc displacement without reduction

Disc perforation (also central disc perforation)
In rare cases, the articular disc, which thins over time, can tear at its thinnest point in the centre. This results in sudden pain, crackling jaw and joint effusion. Top

Eminectomy or eminoplasty of the TMJ
Surgical technique to treat recurrent mandibular dislocation, where the articular eminence of the TMJ is recontoured. 

Exostosis of the condyle
With TMJ arthrosis,  aside from bone resporption, increased local bone growth at the surface of the condylar process of the mandible can also occur. This often leads to retrodiscal perforation. Top

Fibrosis of the TMJ
Not only trauma with bleeding into the TMJ, but also chronic inflammation in the TMJ can cause extensive  adhesions. This can have a severe impact on the mobility of the TMJ.

Fracture of the TMJ (condylar fracture)
We differentiate between fractures to the condyle of the mandible (diacapitular fracture, condylar head fracture) and fractures to the condylar process of the mandible (collum fracture, condylar fracture). We also differentiate between simple and comminuted fractures of the condylar head and the condylar process. Top

Idiopathic (juvenile) condylar resorption (also idiopathic condylysis)
This is a degenerative disease that affects the temporomandibular joints of teenagers. Progressive bilateral rersorption of the condylar heads leads to occlusal changes and may result in an anterior open bite. A specific cause of the disease has not been clearly identified. Top

Cutting and coagulating tissue with light. The Holmium:YAG Laser is especially suitable for use in the temporomandibular joint.

Fibrous tissue that connects two bones to each other. 

Lysis of ankylosis in the TMJ
This surgery involves removing connective tissue from the articular cavity and excess bone that restricts movement of the condyle. There are several options available for joint reconstruction (see TMJ reconstruction). Top

Lower jaw.

Mandibular disclocation (also TMJ dislocation, recurrent mandibular dislocation)
Mostly as a result of extreme mouth opening, the mandibular condyle is displaced from the glenoid fossa anterior to the articular eminence of the temporal bone. The mandible is trapped in this position and the patient cannot close his mouth.

MRI of the TMJ
Magnetic resonance imaging of the TMJ. This technology uses surface coils to provide detailed images in 2 planes of the soft tissue (disc, bilaminar zone) and hard tissue (condylar bone and socket) of the TMJ.

Muscle pain.

Muscular disease. Top

Neuropathic pain.

Inflammation of a peripheral nerve. Top

Repositioning of the disc
A manual or minimally invasive surgical reposition of the articular disc is a successful treatment method in the early stages.

Rheumatoid arthritis of the TMJ
This is a chronic, systemic inflammatory disorder that may also affect the temporomandibular joint. If it progresses to total joint destruction, joint reconstruction is needed. Top

(Conscious Sedation ): Short-term anaesthesia without intubation, "twilight sleep".

Splint therapy
Treatment for craniomandibular system dysfunction (TMD) with the use of a bite guard (see section on splint therapy).

Similar to recurrent mandibular dislocation, the mandibular condyle is displaced anterior to the articular eminence for a very short period of time, but then returns to the glenoid fossa without any manipulation. Subluxation of the mandible is frequently observed in individuals with general joint laxity.

Synovial chondromatosis of the TMJ
In this condition, cartilaginous metaplasia takes place within the synovial membrane of the joint. Cartilaginous intra-articular bodies float freely within the synovial fluid. Progressive enlargement and ossification occur with time. This condition can be treated by arthroscopic surgery. If the loose bodies remain free, they continue to grow larger and more calcified. In severe cases, they may occupy the entire joint space or penetrate to adjacent tissues (middle ear, temporal lobe of the brain).

Synovial fluid of the TMJ
The joint fluid within the joint space.

Synovial membrane of the TMJ
The inner layer of the joint capsule.

Synovitis of the TMJ
Inflammation of the synovial membrane. Top

Perception of ear ringing or other types of noise that seem to originate in the ears.

Temporomandibular disorders.

Temporomandibular joint.

Means Temporomandibular joint dysfunction syndrome or temporomandibular joint disorders.

TMJ locking
Limited mobility of the condyle, limitation to mouth opening, mostly due to disc displacement (internal derangement).

TMJ osteoarthritis
Degenerative joint disease involving the hard and soft tissues, accompanied by acute or chronic inflammation.

TMJ osteoarthrosis
Degenerative joint disease involving the hard and soft tissues without signs of acute or chronic inflammation.

Gliding movement of the mandibular condyle when sliding the jaw forwards or from side to side.

Trigeminal neuralgia
Episodic, intensive pain originating in one or more branches of the trigeminal nerve, the fifth cranial nerve. This pain can occur spontaneously or it may be triggered by a stimulus to a certain area of the face: eating, swallowing, speaking, brushing the teeth or even air currents.

TENS (Transcutaneous electrical nerve stimulation)
Application of electrical current through the skin for pain control and muscle relaxation.

Retrodiscal tissue perforation
Severe arthroses of the temporomandibular joint, where the disc is  brought forward over a long period of time often goes hand in hand with perforation of the posterior disc attachment, the bilaminar zone. The lateral attachment may also be affected. An important symptom is crackling jaw.

TMJ arthroplasty (arthroscopic arthroplasty)
"Plastic“ modelling of the joint surfaces. No plastic is actually used in the temporomandibular joint!

TMJ arthroscope
An optical instrument that allows a detailed view of the anatomical structures in the cavities of the temporomandibular joint. We differentiate between diagnostic and surgical (interventional) temporomandibular joint arthroscopy. Top

Zenker’s retrodiscal cushion
The anatomist Wolfgang Zenker was the first to describe the venous plexus within the bilaminar region comprising a dense nervous network. The tissue expands rapidly by intake of blood when the mandibular condyle moves forward and it also collapses rapidly when the condyle moves back to the glenoid fossa. This mechanism allows free movements of the condylar head. Top



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