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Temporomandibular Joint Syndrome
Updated: Dec 6, 2006
Introduction
Background
TMJ, or temporal mandibular joint, is the synovial joint that connects the jaw to the skull. These two joints are located just in front of each ear. Each joint is composed of the condyle of the mandible, an articulating disk, and the articular tubercle of the temporal bone. The movements allowed are side to side, up and down, as well as protrusion and retrusion. This complicated joint along with its attached muscles, allows movements needed for speaking, chewing, and making facial expressions.
Uyanik et al identifies 3 distinct causes of pain at the TMJ, which collectively fall under the broader term of TMJ syndrome.
- Myofascial pain dysfunction (MPD) syndrome, pain at the TMJ due to various causes of increased muscle tension and spasm. It is believed that MPD syndrome is a physical manifestation of psychological stress. No primary disorder of the joint itself is present. Pain is secondary to events such as nocturnal jaw clenching and teeth grinding. Treatment is focused on behavioral modification as opposed to joint repair.
- Internal derangement (ID), where the problem lies within the joint itself, most commonly with the position of the articulating disc
- Degenerative joint disease, where arthritic changes result in degeneration of the articulating surfaces
Pathophysiology
The pathophysiology is not entirely understood, but it is believed that TMJ dysfunction syndrome arises from both local insults and systemic disorders. Local problems frequently arise from articular disc displacement and hereditary conditions affecting the structures of the joint itself, such as hypoplastic mandibular condyles.
The TMJs also can be affected by conditions such as rheumatoid arthritis, osteoarthritis, and diseases of the articular disks. In addition, hypermobile TMJs, nocturnal jaw clenching, nocturnal teeth grinding, jaw clenching due to psychosocial stresses, and local trauma also play a significant role.
As described by Hegde et al, a strong understanding of how the trigeminal nerve innervates the TMJ and surrounding structures explains the pain and referred pain patterns of TMJ disorders. Irritation of the mandibular branch (V3) of the trigeminal nerve results in pain locally at the TMJ and also to other areas of V3 sensory innervation, which include the ipsilateral skin, teeth, side of the head, and scalp.
Frequency
United States
Currently, an estimated 10 million people have TMJ disorders, and roughly 25% of the population have symptoms at some point in their lives.
Mortality/Morbidity
The morbidity of the disorder is related to significant pain on movement of the jaw. While some patients' symptoms may resolve within weeks, others may have chronic symptoms that persist even with extensive therapy.
One study by Rammelsberg et al followed 235 patients over 5 years. In this study, roughly one third of patients had completely resolved pain, one third had continuous pain over the 5 years, and one third had recurrent episodes with periods of remission.
Race
No apparent association with race exists.
Sex
Female-to-male ratio is roughly 4:1.
Age
- Greatest incidence is in adults aged 20-40 years.
- TMJ syndrome is found infrequently in the pediatric population.
Clinical
History
- Symptoms
- Chronic pain in the muscles of mastication described as a dull ache, typically unilateral
- Pain may radiate to the ear and jaw, and is worsened with chewing
- Locking of the jaw when attempting to open the mouth
- Ear clicking or popping, usually when displacement of the articular disk is present.
- Headache and/or neck ache
- A bite that feels uncomfortable or different from usual
- Neck, shoulder, and back pain
- Bruxism, teeth clenching
- Increasing pain over the course of the day
- History of jaw and/or facial trauma
Physical
- Limitation of jaw opening (normal range is at least 40 mm as measured from lower to upper anterior teeth)
- Palpable spasm of facial muscles (masseter and internal pterygoid muscles)
- Unilateral facial swelling
- Clicking or popping in the TMJ
- Tenderness to palpation of the TMJ via the external auditory meatus
- Crepitus over joint (in advanced disease)
- Lateral deviation of mandible
More on Temporomandibular Joint Syndrome |
 Overview: Temporomandibular Joint Syndrome |
| Differential Diagnoses & Workup: Temporomandibular Joint Syndrome |
| Treatment & Medication: Temporomandibular Joint Syndrome |
| Follow-up: Temporomandibular Joint Syndrome |
| References |
| Next Page » |
References
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Rammelsberg P, LeResche L, Dworkin S. Longitudinal outcome of temporomandibular disorders: a 5-year epidemiologic study of muscle disorders defined by research diagnostic criteria for temporomandibular disorders. J Orofac Pain. 2003;17(1):9-20. [Medline].
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Further Reading
Keywords
temporomandibular joint dysfunction syndrome, TMJ syndrome, myofascial pain dysfunction syndrome, MPD syndrome, temporal mandibular joint, locked jaw, neck pain, movement of the jaw
