UNSTABLE JAW JOINT POSITION and EAR SYMPTOMS – IS THERE A RELATIONSHIP?
TMJ disorders can also cause a number of ear symptoms, including dizziness, ear ringing, stuffed Eustachian tubes, and difficulty hearing. Although we don’t always understand the mechanism, these ear symptoms are often part of a TMJ disorder, because they increase along with the other TMJ symptoms when the TMJ disorder becomes more severe, and they decrease along with the other TMJ symptoms when the TMJ disorder is relieved.
The balance mechanism, located in the inner ear, may be affected. Severe injury to the balance mechanism results in dizziness and nausea. Mild injury to that same system produces feelings of disorientation, inability to concentrate, a tendency to bump into things, and “spaciness”. Tinnitus (ringing, roaring, or buzzing sounds in the ears) has been shown to respond to TMJ treatment in about half of the patients studied.
One cause of ear symptoms in TMJ disorders is probably sterile inflammation of the retrodiscal tissues. Anatomical studies of TMJs with dislocated disks have shown that most of the tissue bruising occurs at the extreme back end of the TMJ, located only 1.5 millimeters from the front of the middle ear. The increased fluid pressure that results from inflammation there can transmit pressure across the thin membrane bones separating the ear from the TMJs.
Increased fluid pressure can push closed the Eustachian tube, which passes very close to the back of the TMJ. If it has been pushed closed for long, it can become narrowed in that area. Subsequently it can be blocked by a cold, allergy, or anything else that causes inflammation of the inner lining of the tube and thereby further narrows its lumen. Blockage of a Eustachian tube can prevent it from equalizing pressure between the middle ear and the outside air and thereby create a stuffy feeling in the ear and difficulty clearing it after changes in altitude.
Another cause of ear symptoms in TMJ disorders may be loss of proper resting tonus in the two tiny ear muscles (the tensor tympani and the tensor veli palatini) which are controlled by the same motor nerve that controls the jaw closing muscles. Increased tension in that motor nerve triggered by reflex protective bracing in response to TMJ tissue damage may cause increased tension in both ear and jaw muscles. Increased resting tension in the tensor tympani muscle, the muscle that tightens the ear drum, may cause the subjective hearing loss that causes TMJ disorder patients to complain they often miss things people say, even though hearing tests show normal results. Increased resting tension in the tensor veli palatini muscles, which pull open the Eustachian tube during swallowing, can interfere with the health and function of the Eustachian tubes.
Some researchers believe that still another cause of ear symptoms in TMJ disorders may be Pinto’s ligament, a fibrous continuity between the sphenomandibular ligament and the anterior malleolar ligament of the middle ear. The petrotympanic fissure between these structures appears to close at about the age of three, but some fibers may continue to pass through it and exert some pressure across it.