Temporomandibular Dysfunction and Headache

Many individuals with ongoing headache can benefit from a thorough physical therapy evaluation of the jaw and its surrounding tissues. The temporomandibular joint (TMJ) and its muscles and surrounding soft tissue, may be contributing factors for some headaches. Headaches involving the facial area, the forehead, the sides of the head or over the temporomandibular joint itself could indicate TMJ and/or jaw muscle involvement. Headaches that are exacerbated by chewing, yawning, or talking are also indications. Patients who have a dental history of clenching or grinding their teeth, especially at night, with increase in headaches upon arising in the morning, should be assessed.

There is much confusion over proper terminology when it comes to the jaw, even within the medical profession. You may have been told you have TMJ, TMJD (temporomandibular joint dysfunction), or cranio-facial dysfunction, to mention a few. These terms are confusing. Some refer to the joint alone, some also include the jaw musculature and soft tissue, and others include the upper cervical spine.

The jaw is not a simple hinge joint. It moves in a 4:1:1 ratio of 4 parts opening to 1 part lateral excursion (lateral movement) to 1 part protrusion (forward movement). It is suspended from the muscles of mastication (the muscles we use to chew). This delicate balance can be disrupted to the point of causing symptoms which contribute to headaches.

Poor posture is one of the leading causes of disorders involving the jaw and its muscles according to Mariano Rocabado, PhD; a world renowned physical therapist who has studied the jaw for 35 years. A forward head position leads to a change in the resting position of the mandible (the jaw bone) and the tongue---lowering both. This changes not only the occlusion (contact) of the teeth, but significantly affects the muscles of mastication. Sit up tall and feel how your teeth meet. Now really slouch. Do you see how your teeth hit differently?

The resting position of the jaw is such that the front third of the tongue should rest on the roof of the mouth with the tip of the tongue just behind (without touching) the top front teeth. Your teeth should be slightly apart and your mouth closed. In this position, you will breathe through your nose. This normally occurs with good posture. Slouch and see how the teeth tend to separate and the tongue position drops into the mandible. This leads to increased use of accessory respiratory muscles (the muscles in the upper chest and shoulders) and decreased use of the diaphragm.

With proper posture we open our mouths primarily with the help of gravity and, to a lesser degree, from the supra-hyoid muscles (located under the chin and in the throat area). In the forward head position, these muscles are strained. They contract to open the mouth so they can resume their proper resting length. Now the muscles that close the mouth (located in our cheeks and temple areas) are strained and they contract to resume their resting position. We have a tug of war (called "parafunction ") occurring. This can lead to muscle spasms and trigger points.

Trigger points seem to occur more often in the muscles closing the jaw than those that open it. Trigger points in the temporalis (a muscle that closes the jaw and is located along the side of the head) radiate and can contribute to headaches along the eyebrow, the side of the head and to our upper teeth. Trigger points in the masseter (another muscle that closes the jaw and is located in the cheek) can radiate to the eyebrow, sinus area, and our upper or lower back teeth.

Facial asymmetry gives us input on balance between the jaw and muscles. This imbalance has been researched in relationship to one-sided headaches. We look at asymmetry not only from the front view but from the side as well. There is a higher incidence of asymmetry in patients with painful craniomandibular disorders, unilateral headaches and history of head injury.1

Hypermobility (excessive movement in their joints) can occur also. It can stress the joint itself, the disc, the ligaments, muscles and sometimes can cause the joint to lock. Systemic hypermobility occurs in females more than males by a 3:1 ratio. With a combination of hypermobility, trauma, and parafunction, symptoms are more likely to occur.2

What happens if we have a cold, allergies, etc? We breathe through our mouth. This leads to dropping the jaw and a forward head position so we can open up the lower airway. The results of this are the equivalent of sitting with very poor posture.

Improper teeth contact leads to strain and imbalance in the joints themselves. If unresolved, the muscles become involved. Evaluation by a trained dentist may be useful in this case.

Grinding, clenching, chewing gum, fingernail or pencil biting or even resting your chin on the hand can all lead to parafunction---the tug of war mentioned earlier. These are habits to be broken. Smoking and playing certain musical instruments (violin, clarinet) can add to parafunction. A bite splint is meant to protect the surfaces of your teeth. However, those of you who have bitten through it could be promoting parafunction activity instead of treating it.

Physical therapists with a background in jaw treatment can often help. They can evaluate posture, cervical spine mechanics, proper jaw movement or restrictions, strength of muscles and trigger points. With this information they can implement the appropriate treatment and work in conjunction with your other doctors.

What can you do right now? Initially, sit up straight. "Sit tall and lift your chest " are cues that can get you started. A physical therapist can fine tune these techniques. Correcting posture is extremely important and failing to do so can significantly interfere with the effectiveness of your physical therapy treatment.

Secondly, consider your ergonomics both at home and at work. When using a computer, the monitor, chair, mouse, and keyboard need to be at the correct height. You need to face the monitor and not have your head turned to the side, or looking up or down. With a laptop computer, you will need a separate keyboard and mouse to attain this set-up. If you cradle the telephone between your ear and your shoulder, replace it with a headset or use a speaker phone. Sleeping on your stomach not only puts the neck in a rotated position but can also put pressure on your jaw.

Thirdly, work toward eliminating habits such as gum chewing, biting your nails, and resting your chin on your hand. Give this some thought. For one patient, she found she needed to eliminate her habit of chewing on unpopped popcorn kernels. Pay attention to any tendency toward clenching and grinding. With these things in mind, you are working toward minimizing or eliminating the part that the jaw and its muscles play in contributing to your headache.

Parafunction, in addition to directly causing pain, could contribute to headache by promoting nociceptive (pain-related) signals to enter the brain. Migraine mechanisms could be activated or could make them more likely to occur by sensitizing these neural structures. Either way, jaw problems can result in pain, both directly and by aggravating more complex headache mechanisms. Therefore, relieving the jaw disturbance can reduce the tendency toward headaches beyond the pain in the jaw.

Finally if needed, seek out further evaluation from a physician, dentist, and physical therapist with TMJ experience.

Ellen Lecureux, P.T., MHNI

  1. Schokker RP, Hansson TL, Ansink BJ,Habets LLL. Craniomandibular asymmetry in headache patients. J Craniomandibular Disord. 1990;4:205-209.
  2. Westling L, Carlsson GE, Helkima M. Background factors in craniomandibular disorders with special reference to general joint hypermobility, parafunction, and trauma. Craniomandib Disord. 1990;4:89-98.