Position of dislocation in TMJ disease classifications
In modern medical practice, temporomandibular joint pathologies are systematically categorized in several ways. In the ICD-10, TMJ diseases are distributed across two main classes:
- Class XII (Maxillofacial anomalies): This section directly includes TMJ dislocation and subluxation, as well as pain dysfunction syndrome, clicking jaw, unspecified pain, joint stiffness, and the presence of osteophytes.
- Class XIII (Diseases of the musculoskeletal system): This groups various arthropathies (infectious, traumatic, inflammatory polyarthropathies) and arthroses (osteoarthritis, primary, and polyarthrosis).
In addition to the international system, specialists rely on the national classification developed in 1997 (P.G. Sysolyatin, V.M. Bezrukov, A.A. Ilyin). It divides all pathologies into two major groups:
- Articular: inflammatory processes (arthritis) and non-inflammatory disorders (internal derangements, osteoarthrosis, ankylosis, tumors, and congenital anomalies).
- Non-articular: bruxism, masticatory muscle contractures, and pain dysfunction syndrome.
Diagnostic methods for TMJ pathologies
To establish an accurate diagnosis for various dysfunctions, including internal derangements and dislocations, a wide range of instrumental examinations is used. Modern technologies make it possible to visualize not only bone fragments, but also soft tissues (the capsule, ligamentous apparatus, articular disc) during various phases of jaw movement.
Functional and biomechanical methods:
- Ultrasound transducers: record micro-movements of the mandible.
- Electromyography: registers the bioelectric activity of the masticatory muscles. This is critically important for understanding the etiology of the disease, choosing therapeutic tactics, and monitoring treatment outcomes.
- Phonoarthrography: a method for recording sound phenomena within the joint. Sound is a direct indicator of the quality of interaction between the articular surfaces and the disc.
- Arthrocentesis: aspiration of synovial fluid for laboratory analysis.
- Arthroscopy: an invasive technique allowing visual inspection of the joint cavity from the inside. It demonstrates high efficacy for both the diagnosis and treatment of internal derangements.
Radiological imaging: Serves as the baseline standard for examination. Traditional radiographic methods include orthopantomography, zonography, and Pordes-Parma and Schüller projections. However, CT and MRI possess the highest informational value. They generate three-dimensional images of structures. Furthermore, dynamic MRI allows for the analysis of the dentognathic system's function at all stages of chewing and a detailed assessment of the condition of the soft tissue elements of the joint.
Associated trauma and inflammatory processes
Trauma to the maxillofacial region can lead not only to the displacement of articular surfaces, but also to fractures of bone structures and the development of inflammation.
Alveolar process trauma Fractures of the alveolar process are more common in the maxilla because its bone tissue is thinner, longer, and perforated by numerous channels for vessels and nerves. During impacts in the frontal plane, fragments typically displace posteriorly (into the oral cavity). Clinically, this manifests as bleeding, malocclusion (only teeth on the displaced fragment contact), and sharp pain when closing the jaws. Diagnosis of such conditions requires intraoral or lateral radiography, and treatment consists of repositioning the fragment under anesthesia and fixing it with a smooth splint-archwire (if stable teeth are present).
TMJ arthritis Infection entry (via metastatic pathways or from adjacent purulent foci) or sustained trauma can provoke arthritis—inflammation of the joint elements. Acute, subacute, and chronic stages of infectious non-specific arthritis are distinguished, as well as acute and chronic courses of traumatic injuries.
Of particular note is rheumatic arthritis, which develops against the background of a systemic infectious-allergic lesion of connective tissue. It is characterized by the "migration" of pain across large symmetrical joints with potential involvement of the TMJ. Patients complain of local skin hyperthermia, edema, exudate formation, and severe pain radiating along the branches of the trigeminal nerve. Inflammation typically subsides within 5–7 days without the formation of coarse scars, after which symptoms of cardiac involvement (rheumatic myocarditis) come to the forefront.
Briefly: answers to topical questions
What types of mandibular dislocations are distinguished based on the direction of displacement of the articular head?
Depending on the direction of displacement of the articular head, anterior and posterior mandibular dislocations are distinguished.
- Anterior dislocation — occurs with excessive lowering of the mandible, when the articular head moves anteriorly, beyond the articular tubercle onto its anterior slope.
- Posterior dislocation — characterized by the displacement of the articular head posteriorly, towards the mastoid process.
Anterior dislocations are the most frequently encountered in clinical practice.
What manual reduction methods are used for acute anterior mandibular dislocation?
Several conservative methods are used for the manual reduction of an anterior mandibular dislocation.
- Hippocrates' method — the physician presses downward on the lower molars with their thumbs, then displaces the jaw backward, returning the heads into the articular fossa.
- P.V. Khodorovich's method — the thumbs are fixed on the oblique lines of the mandibular ramus, and the nail phalanges are placed in the retromolar region, after which reduction proceeds according to Hippocrates.
- G.L. Blekhman's method — index fingers press downward and backward on the coronoid processes.
- Yu.D. Gershuni's method — an extraoral method in which the physician presses on the tips of the coronoid processes externally through the cheek tissues backward and downward.
What anatomical features of TMJ structure contribute to the development of recurrent mandibular dislocation?
The development of recurrent anterior mandibular dislocation is facilitated by:
- decreased elasticity of the ligamentous apparatus and capsule of the temporomandibular joint;
- decreased height of the articular tubercle;
- flattening of the articular head;
- significant stretching of the joint capsule and ligamentous apparatus;
- alterations of the articular disc: disruption of its size and shape;
- complete edentulism in elderly individuals.
Class and exam questions
What is the advantage of MRI over X-ray in TMJ examination?
MRI allows detailed visualization of not only the bones, but also soft tissue structures: the capsule, ligaments, articular disc, and surrounding muscles, including dynamically during jaw movement.
Why is phonoarthrography performed?
This method registers intra-articular sounds, which help assess the degree of impairment and the quality of interaction between the articular disc and bone surfaces.
What else to study on this topic
- Classification of alveolar process fractures according to K.S. Yadrova
- Technique of teeth immobilization with a smooth splint-archwire
- Etiology and pathogenesis of infectious TMJ arthritides
- Clinical presentation of rheumatic joint involvement
- Radiological signs of alveolar bone fracture
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Other topics in the section "Chapter 11. Non-ballistic and ballistic facial injuries. Thermal and radiation lesions of the maxillofacial region (V.V. Afanasyev)"
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