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The temporomandibular joint is one of the most important joints in the body. It's 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.
Just as a disk can pop out of alignment in your neck, this can also happen in your jaw. This occurs when the ligaments that normally hold the disk onto the lower jaw-bone become stretched or torn due to a past traumatic injury, or from repetitive loading of the jaw joint. TMJ arthritis will 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 main nerve for the jaw joint is attached to the back of the disk, so when the disk is slipped out of position, there is frequently compression of the nerve and blood vessels causing pain and inflammation around the ear and temple. When this occurs the jaw muscles will tighten up around the jaw joint in order to protect it. This can commonly lead to jaw pain, neck pain and headaches. Disk displacements commonly have limitations in the 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. There are two main types of disk displacements outlined below.
TMJ disk displacement with reduction (jaw clicking)
The jaw will usually “click” or “pop” when this happens it causes asymmetric movements of the jaw. The “clicking” occurs when the disk slips in and out of position as the lower jaw bone moves during jaw function.
TMJ disk displacement without reduction (locked jaw)
This occurs when the ligaments are stretched more and the disk slips too far out of position so that it can no longer “click” back into place. It then acts like a door-jam and blocks the normal movement of the joint. As the mouth opening is limited it is also called “locked jaw” even though typically a person can still open two finger widths.
This occurs when the there is more stress put on the jaw joint than the body is able to handle. This can occur because of a structural problem within the jaw (i.e. disk displacements or certain bad bites), systemic conditions (rheumatoid) or due to excessive loading forces on the jaw joint. The cartilage surrounding the bone is damaged before the damage to the bone. The cartilage helps bring fluid in and out of the joint thereby eliminating waste products and bringing in nutrients. Typical symptoms include crackling or crepitation when opening and closing, pain in and around the ear, ear stuffiness, and bite shifting.
Pain can also arise from the jaw muscles. What is commonly not realized is that the main jaw muscles are located in the temples, sides of the face, and front of the neck. Additionally, the neck muscles assist in jaw function therefore are also affected by jaw dysfunction.
When the nerve that is connected to the muscle becomes irritated small nodules or contractures form causing the muscle to become tight and painful. These contractures are called trigger points. Trigger points will often refer pain into distant locations. For example it is very common for jaw muscles with myofascial pain to refer pain into the teeth or ears. In addition to pain, muscles with myofascial pain also fatigue more easily and have decreased strength and range of motion. Headaches in the temples are usually the result of myofascial pain within the temporalis muscle, which is a jaw closing muscle. This can occur when the jaw muscles are chronically strained such as in teeth clenching or poor posture, through an acute trauma, or with nerve injury or jaw joint dysfunction.
This can occur when there is chronic strain from the temporalis muscle pulling on the tendon that attaches to the mandible. This can cause sharp headaches in the temples, just to the sides of the eyes.
This is usually felt as a sharp to aching pain in the region behind the jaw bone and below the ear. It can be a result of bad bite or from a traumatic injury (commonly whiplash).
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