Temporomandibular joints — TMJs — are located on both sides of the face in front of the ears, connecting the jawbone (mandible) to the skull (temporal bone). They're the most complicated joints in the human body, providing rotation (pivoting) movement like all joints, as well as sliding movement, called translation. That's what allows us to open our mouths wide and move our jaws from left to right. Between the top end of the jaw (condyle) and the socket in the skull is a disc of cartilage, which — like the discs in the neck and back — serve as shock absorbers, protecting the bones from hitting each
The joints work with the neuromuscular system
The movement of the jaw is orchestrated by a complex set of muscles, which are, in turn, controlled by the body's local and central nervous system. Together, they're called the neuromuscular system. The whole jaw-joint system is held together by ligaments, which limit the range of motion in all directions — as they do in all the joints of the body.
A unique system of many parts
The TMJ joint system is unique in many ways. The left and right joints must coordinate, working at the same time for the jaw to move. While the opening, lateral and forward movements of the jaw are controlled by the shape of the bones and are a function of muscles and ligaments, the closing end-point of the jaw movement is controlled by the coming together of the teeth — the bite or occlusion. No other joint in the body has such a rigid end-point limit.
The proper, healthy function of the TMJ system requires normal structure and function of all the component parts, including muscles, nervous system, ligaments, joints (bones, discs and connecting tissues) and the dental occlusion.
Temporomandibular disorders (TMJ / TMDs) are often called "TMJ" by doctors, patients and even insurance companies, although the term TMJ actually refers only to the jaw joints themselves.
TMD/TMJ describes a group of diseases that can involve the jaw joints, the muscles that control jaw movement and the dental occlusion. TMJ / TMDs are physical disorders arising from an imbalance in the delicate working relationship of the jaw and skull with the muscles that move the jaw, as well as the nervous system associated with these systems. This imbalance results in muscle fatigue, spasm and/or joint dysfunction, and even changes in the teeth, which in turn cause a variety of symptoms, unique for each person.
The symptoms of TMJ / TMD, which affect millions of adults and children, can gradually appear with no apparent, specific cause. They also can occur after a trauma, such as a traffic accident or a blow to the face. Even subtle repeated traumas, like clenching the teeth or excessive gum chewing, nail biting or cradling a phone between your shoulder and the side of your head can cause TMJ / TMD . These conditions can also be caused by a bad bite (dental malocclusion), which is not synchronized with healthy muscle and joint function. Systemic diseases and developmental abnormalities also can cause TMJ / TMD.
Stress may play a part
Stress and tension may awaken a quiet, asymptomatic TMJ / TMD or aggravate an existing temporomandibular condition. However, stress alone does not cause TMJ / TMD if a patient has healthy dental occlusion and muscle and jaw function.
A thorough exam is critical
All too often patients are classified as "chronic pain patients" and their complaints pigeonholed as stress or psychological disorders. These patients may be relegated to treatment focusing only on medication and counseling, with no treatment of the physical cause of their illness. A thorough analysis of each patient is essential to determine the source of pain. Early and appropriate treatment of a TMJ / TMD may avoid the progression to a chronic pain state.
If you think you may have a temporomandibular disorder, ask yourself these questions.
- Do you experience pain in your face, ears, below or in front of your ears or headaches for which your medical doctor has not found a cause?
- Do your ears muffle or feel clogged?
- Do your jaw joints (TMJ), located in front of your ears, hurt when you chew and do they make clicking or crackling noises?
- Do your facial muscles feel tired or stiff when you awaken, during the day, after a lot of speaking or when yawning?
- Do you clench your teeth together while sleeping or awake? A spouse can often tell you about your jaw muscle activity during sleeping.
- Do you have headaches in the sides of your temples?
- Are you able to open your mouth freely, smoothly and as wide as you are accustomed to doing?
- Can you move your jaw from side to side with your mouth open?
- Do you experience episodes when your jaw feels that it locks open or shut?
- Do you feel that your upper and lower teeth don't fit together as they usually do?
- Is your bite comfortable? Is chewing tough foods uncomfortable or painful?
- Do you experience dental pain in lots of teeth for which your dentist has found no cause?
- Are your teeth chipping and are the front teeth worn flat on their edges?
- Do your upper front teeth completely cover the lower teeth when you bite together?
- Have your teeth been shifting, creating spaces or crowding for no apparent dental reason?
If you have answered "YES" to any of these questions, you may have a temporomandibular disorder and should seek care from a dental TMJ expert, who has experience and training in this field.
An initial visit with a TMJ / TMD dental expert should begin with a careful and comprehensive review. This includes the history of the onset of the problem, how it has progressed, what medical evaluations and treatments have already been performed and their results. It is very important to discuss your TMD / TMJ symptoms, for they provide invaluable clues to the nature of your problem.
TMJ / TMDs manifest as a variety of symptoms, including headaches, ear pain, pain in the temporomandibular joints (TMJ) and disruption of normal mandibular function. Symptoms commonly associated with TMJ / TMD relate to the dental and oral structures, the jaw, TMJ and masticatory (chewing) muscles, or may appear to relate to nearby head and neck structures.
Because of the complex anatomic, physiological and neurological interrelationships in the head and neck, the symptoms of TMJ / TMD s can coexist or mimic symptoms of other diseases. It is important for patients to be evaluated by the appropriate doctor(s) to rule out the presence of other primary diseases.
TMJ / TMD patients frequently experience a combination of symptoms, some of which are listed below.
Headaches, facial, dental pain; Pain in the jaw joints or on jaw movement; Ear pain, tinnitus, ear pressure; Neck, back, shoulder and chest pain.
Jaw movement: limited, deviated, slow or irregular; Head movement: limited range of motion; Ears: muffling, dizziness, clicking; Throat: difficulty swallowing, prolonged speech; Jaw Joint: locked or dislocated jaw, facial asymmetry.
Traumatic occlusion, clenching, grinding (bruxism); Wear (abrasion), chipping on natural, restored or denture teeth; Looseness of teeth: bone loss without gum inflammation; Movement of teeth: spreading, crowding, loss of teeth & bite changes.
Patients with TMJ / TMD frequently describe the symptoms listed above even though the TMJ / TMD may not be the actual cause of some of the symptoms. Each person suffering from TMJ / TMD may experience a different constellation of symptoms, which can change over time.
The table that follows shows the occurrence of symptoms in two large TMJ / TMD populations; the larger group (3,681) were interviewed and examined by Dr. Barry Cooper, while the smaller sub-group of that larger group of patients (1,182) were actually treated in a research study reported elsewhere in this website. Their symptoms are presented here to illustrate typical symptoms of TMJ / TMD patients.
(in % of subject population)