I thought long and hard before writing this article, because of the complex nature of the explanation. However because this problem is so debilitating and terrible, I felt encouraged to go ahead.
Some of this article may seem a bit “Dusty”, but if you are a sufferer then please do read on as I may be able to help. And before I write anything more, this is not some half-baked idea I dreamt up – it is solid medical fact.
What Is Tinnitus?
Tinnitus comes from the Latin word “tinnitus”, meaning “ringing”.
It is the perception of sound within the human ear in the absence of corresponding external sound and is not a disease, but a symptom. About 1 in 5 people report it as a symptom when questioned.
Causes (aetiology) (etiology)
If you check a medical textbook or search online, you will see a list as long as your arm. However the most common causes are:-
If none of these apply to you and you have seen an ENT specialist who can find no cause for your problem, then the answer probably lies in your jaw joint. (Temperomandibular Joint or TMJ) Many people will be aware of TMJ Dysfunction, but few will know it can cause Tinnitus. So the question is “How is this possible?”
Unfortunately we need to look at the anatomy of the ear and the TMJ to fully understand what exactly is going on. But before we do that, try standing in front of a mirror. Place a finger lightly in front or you ear and open and close your mouth. You may have to move your finger a little to find the joint, but when you do, you will feel the joint moving. Notice how close together your ear and jaw joint are.
This proximity is no coincidence. In the developing embryo the lower jaw (mandible) and much of the ear originate from the same tissue – “Meckel’s Cartilage” and as a result of this common origin a few remnants remain that physically connect the middle ear to the mandible. But more of this later…..
The ear consists of 3 parts. These are:-
The External Ear– the part you can see and the ear canal which ends at the ear drum.
The Middle Ear– a small air-filled chamber that contains 3 tiny bones or ossicles called “Malleus” “Incus” and “Stapes”, which are joined together and transmit vibrations from the ear drum to the…
Inner Ear– this part of the auditory apparatus is responsible for sending the vibrations picked up by the ear drum to the brain where it is interpreted into sound that we recognise such as speech or music. The inner ear also looks after balance.
So to sum up.
Sound waves travel along the ear canal and cause vibrations in the ear drum. These vibrations are then transmitted across the middle ear by the 3 ossicles to the inner ear and from there to the area of the brain that deals with hearing.
The Temperomandibular Joint (TMJ)
This is a small, but complicated joint. It is a ginglymoarthrodial joint which means it rotates, (as most joints do), but also slides and it is this sliding component that causes the problems.
The joint itself consist of the:-
“Condyle” which is part of the lower jaw and looks like a ball.
“Glenoid Fossa” which is part of the skull and looks like a depression, so the Condyle fits into the Glenoid Fossa.
Between these two parts sits the “Disc” which keeps the two separate and offers some cushioning and fluid which reduces friction. Finally the whole lot is surrounded by the “Capsule” which helps keep everything in place.
Under normal circumstances, when the upper teeth and lower teeth are in occlusion (biting together) the Condyle sits nicely in the Glenoid Fossa separated by the Disc. Then as the mouth begins to open, the Condyle just rotates and as the mouth opens yet more, the Condyle starts to slide forwards and downwards. At the same time, the Disc moves backward over the top of the Condyle. When the mouth closes, the reverse takes place.
When we are at rest, (not talking or eating), our upper and lower teeth should be apart by a few millimetres. This allows the muscles that work the jaw to recover from their exertions. If however you constantly grind your teeth or clench your teeth or have a malocclusion the muscles carry on over-working and eventually go into spasm – like getting cramp when swimming.
The result of this muscle spasm can lead to abnormal positioning of one or both Condyles which in turn places more stress on the muscles which in turn leads to more muscle spasm.
So how does all this explain Tinnitus?
At the start of this article I mentioned the common embryology of the ear and TMJ and how some remnants of this commonality still remain. There are in fact two such remnants that are relevant:-
Although many TMJ specialists believe the DML to be the important structure in the cause of Tinnitus, H.J. Kim et. al. in “Surgical and Radiologic Anatomy”
Volume 26, Number 1, 39-45, showed conclusively that it is the ALM that is the important structure.
The ALM is a tiny ligament that runs from the Malleus (the first of the ossicles in the middle ear and the one resting against the ear drum) to the disc within the TMJ. So if the Disc is not sitting correctly within the TMJ, this can stretch the ligament, which in turn places excessive tension on the 3 ossicles, some other small but important muscles within and around the ear and the ear drum itself. And it is this that causes Tinnitus.
Fortunately this is pretty straightforward and follows standard TMJ treatment regimes.
In the majority of cases, dis-occluding the teeth (taking the teeth out of contact from each other) works extremely well.
Fitting a night guard, (which as the name suggests is worn at night) is an extremely convenient way of doing this, as it does not impinge on the day to day activities of the wearer.
These are usually made of a pliable plastic material and fit over the lower or upper teeth in such a way that the TMJs are “forced” into a neutral position, along with their associated discs, thereby reducing excessive stresses on the 3 auditory ossicles via the ALM
Tinnitus is an affliction affecting a sizable portion of the population, but at its worse it is an appalling condition which I, as a non-sufferer, can only begin to imagine. Standard TMJ treatment will help a proportion of Tinnitus sufferers whose medical attendants have found no organic or other obvious causes.
It is worth mentioning in passing that many other aural problems are related to TMJ Dysfunction.