The Temporomandibular joint (TMJ) is the joint that connects the jawbone to the skull. It can be found on either side of the jaw, and is one of the most complex joints in the body. The TMJ – along with the surrounding muscles – allows the jaw to move from side to side, up and down, back and forth while chewing, swallowing and talking. When the structures that form the TMJ are out of sync, a joint disorder (called Temporomandibular joint disorder) will occur.
Temporomandibular joint disorder (TMD) affects this joint causing pain and difficulty moving the jaw. In some cases, the real cause of TMD is not known, even though many factors and conditions such as Bruxism, trauma to the head, neck and jaw or arthritis can lead to the development of the disorder.
Health conditions often associated with TMD include:
- Chronic fatigue syndrome
- Chronic headaches
- Sleep disturbances
- Irritable bowel syndrome
Chronic fatigue syndrome
Chronic fatigue syndrome is a disorder characterised by extreme fatigue for which there is no reasonable medical explanation. Chronic fatigue can get worse during physical activity, mental stress and even everyday tasks. However, it does not get better when a person lies down and rests. The real cause of this syndrome is not known but it is believed that viral infections, psychological stress or a combination of factors may trigger it.
Signs and symptoms of chronic fatigue syndrome – apart from tiredness – include unexplained muscle pain, headaches, extreme exhaustion that lasts longer than 24 hours and is not improved by rest, loss of concentration, loss of memory, a sore throat, difficulty sleeping and feeling even more tired after sleep, joint pain that moves from one joint to the other throughout the body, and enlarged lymph nodes in the neck and armpits.
People suffering from chronic fatigue syndrome appear to be more prone to TMD. The reason for this is not known. Sometimes TMD is diagnosed first, which is believed to trigger chronic fatigue syndrome. However, in other cases, TMD is diagnosed after chronic fatigue syndrome, making it even more difficult to treat and manage.
Vertigo is a sensation of dizziness and feeling out of balance. Generally, vertigo results from problems with the inner ear such as Meniere’s syndrome, benign paroxysmal positional vertigo, vestibular neuritis or labyrinthitis. However, in certain cases vertigo can be caused by headache, brain issues, injuries to the head and neck, or even the use of certain medications.
Common signs and symptoms of vertigo include spinning, swaying, feeling unbalanced, tilting, being pulled to one direction, nausea, vomiting, excessive sweating or ringing in the ears.
TMD is often associated with vertigo. The TMJ connects the jawbone to the temporal bone of the skull, close to the ear, where the vestibular system in charge of body balance is located. When any part of this system – especially the labyrinth – is disrupted, the brain will receive mixed signals, often leading to vertigo. When the TMJ becomes inflamed or its structures misaligned, the fluid inside the labyrinth will send unclear signals to the brain, causing a feeling of dizziness or vertigo.
Sinusitis is an inflammation of the tissue lining the sinuses. Conditions that lead to sinusitis include the common cold, allergic rhinitis, a deviated nasal septum, or nasal polyps. Types of sinusitis range from acute, sub-acute, chronic or recurrent depending on the length and recurrence of its signs and symptoms.
Characteristic signs and symptoms of sinusitis include facial pain or a sensation of pressure, a stuffed and runny nose, cough and nasal congestion, loss of smell, fever, dental pain, bad breath, and fatigue.
In cases of TMD, it is common for patients to complain about pain and pressure in their sinuses. In such cases, there is no sinus infection present. The discomfort is due to ‘referred’ or ‘reflective’ pain, where pain is felt at a location other than the site of the painful stimulus. In such cases, diagnosis can be difficult because it’s uncertain whether this is TMD or a sinus problem. Bruxism, or constant teeth grinding especially during sleep, can lead to sinus symptoms even though the real problem is TMD.
Studies have revealed a close relationship between TMD and tinnitus in that people dealing with TMD are more prone to tinnitus. Those suffering from head or neck injuries are also more likely to have tinnitus.
TMD alters the intensity of tinnitus when moving the mouth, jaw, face or neck. Three theories attempt to explain this. Firstly, the muscles used for chewing are near the muscles of the middle ear. Secondly, the ligaments attached to the jaw are thought to be connected to one of the bones in the middle ear. Thirdly, the nerves supplying the TMJ are also connected to the part of the brain that deals with hearing and interpretation of sound.
TMD is often the source of migraine or tension headaches originating in the muscles underneath the jaw and in the cheeks, on either side and on top of the head. Any problem with these muscles combined with misalignment of the TMJ can cause migraine or tension headaches or can make those headaches worse.
What exactly is a migraine headache? It is often felt as a throbbing pain, usually on one side of the head, but sometimes on both. Other signs and symptoms of migraine are sensitivity to light, smell, and noise, during or even after a headache starts.
Even depression can relate to TMD. Even though there is no scientific explanation of the relationship between the two conditions, people suffering from chronic pain in cases of TMD are more likely to suffer from depression.
Chronic pain can cause chemical changes in the brain, especially in the area that’s in charge of our emotions. People dealing with TMD find it more difficult to handle daily tasks and deal with their emotions, which can lead to anxiety and depression. According to Harvard Health Publications, this is a vicious circle: chronic pain due to TMD will have a negative effect on the emotions, causing depression, while depression will intensify chronic pain.
TMD is characterised by chronic pain, and a person dealing with chronic pain normally has difficulty sleeping.
When the jaw does not function properly, the tongue blocks the airway, causing oxygen deprivation. The body tends to react to this lack of oxygen by waking you up.
Fibromyalgia is characterised by musculoskeletal pain often accompanied by fatigue, mood swings, sleep problems, and memory problems. The disorder is more common among women than men.
People with TMD are more prone to fibromyalgia. The corollary is also true, with people suffering from fibromyalgia being more prone to TMD. The reason for this is unknown. However, not everyone diagnosed with fibromyalgia is at risk of TMD, while not everyone with TMD will develop fibromyalgia. But for some reason, these two medical conditions are linked to one another and often seem to be associated.
Irritable bowel syndrome
TMD and irritable bowel syndrome (IBS) are comorbid chronic pain disorders, which simply means they often exist simultaneously. Both conditions are thought to be triggered and exacerbated by stress.
Studies have shown that people suffering from irritable bowel syndrome demonstrate structural changes in specific parts of their brain. These studies demonstrate a decrease in the white and gray matter in areas of the brain that regulate emotions, inhibit pain and process visceral information. Stress and prevalence in women are common to both TMD and IBS. The signs and symptoms of the two conditions seem to fluctuate with the menstrual cycle, leading researchers to suggest that estrogen may play a role in both.