The Temporomandibular joints are the most important joints in the body. Its’ important functions include chewing, biting, talking, singing and kissing. Similar to other joints in your body it is composed of bones, ligaments, disks, cartilage, joint fluid, nerves and blood vessels. Damage to any of these structures can result in pain or dysfunction.
There are also several important differences between the TMJ and other joints. Two of the most important of these differences is that each person has a right and a left TMJ that are connected together by the lower jawbone. Additionally, when the mouth is closed there is the connection between up to 16 pairs of teeth. Therefore, the position and function of one TMJ affects the position, function of the other TMJ; and the dental bite affects the position, and function of both TMJ and vice versa. As the TMJ articulates with the skull, changes in head posture can also affect TMJ function. Injuries to the neck such as during a whiplash injury will alter TMJ mechanics and can result in jaw pain and dysfunction. The tongue position in speech and swallowing and the pharyngeal airway can also alter TMJ position and function.
There is a higher incidence of TMJ disorders in young women and estrogen has been shown to modulate pain and inflammation within the TMJ. Women also have a higher incidence of generalized ligament hypermobility which can influence the TMJ. Due to these factors it is important that anyone treating these disorders has the expertise to evaluate: the teeth, the dental bite, TMJ, neck, jaw and neck muscles, pharyngeal airway, tongue position and systemic conditions, otherwise the treatment may not only be ineffective but may negatively affect the other associated structures.
How Does My TMJ Work?
The disk sits between the upper and lower jawbone and is attached by ligaments mainly on the sides and on the backside of the disk which helps to stabilize the disk in position. When you open your mouth the lower jawbone rotates in the socket like a hinge; and then as you open wider, the lower jawbone and disk slide forward.
The disk, attached by the ligaments, should move together with the lower jawbone. Stretching of the ligaments, breakdown in the bones (arthritis) or cartilage, scar tissue formation, or changes in the lubrication system (synovial fluid) can cause the disk to become stuck out of position leading to pain, jaw locking, jaw clicking and popping, and bite shifting. This can then lead to muscle pain within the head, ear and neck and can be a trigger for migraine disorders.
What are the Symptoms of a TMJ Disorder?
The most common symptoms of TMJ disorders (TMD) include headaches, jaw and facial pain, ear pain, jaw clicking or grinding, bite shifting, ear stuffiness and limited mouth opening. Other common symptoms include neck and shoulder pain, tooth pain, throat pain, difficulty swallowing, ringing in the ears (tinnitus), dizziness, eye pain, and sinus congestion.
TMJ Disk Displacements
Just as a disk or meniscus can pop out of alignment in your knee or back, this can also happen in your jaw. This typically occurs when the ligaments that normally hold the disk onto the lower jawbone become stretched or torn due to a traumatic injury. It can also happen less frequently from repetitive loading of the jaw joint. TMJ arthritis and damage to the cells that make the joint fluid will also increase the likelihood of a disk displacement.
The disk works as the shock absorber for the joint, and when it is out of position, this can lead to arthritis in the jaw joint and adhesions to the disk. Additionally, the innervations for the jaw joint is attached to the back-side of the disk; so when the disk is slipped out of position, there is frequently compression of the nerve area and blood vessels causing pain and inflammation around the ear and temple.
When this occurs the muscles will tighten up around the jaw joint in order to protect it. This can commonly lead to jaw pain, neck pain and headaches. People with disk displacements commonly have joint noises and/or limitations in their ability to open the jaw or to move it from side to side. Additionally, at times it will shift the bite so that a person is not able to close their teeth into their normal positions.