The connection between TMJ and its numerous symptoms is sometimes difficult to see. When one condition causes so many symptoms, the links can seem tenuous. The connection between TMJ and tinnitus (ringing in the ears) always seems natural because the ear is so close to the jaw joint. But they’re even closer than you think: the tiny bones in our ear are actually jaw bones that have been changed by evolution into your jaw joint.

Your Inner Reptile

In the upcoming PBS series, Your Inner Fish, based on the book by Neil Shubin, scientists explore the evolutionary legacy left by some of our ancestors. In this clip, researchers explain how the jaw bone of our ancient ancestors, mammal-like reptiles, transformed over time from a primitive reptilian jaw, which had three bones in their jaw and one in their ear, into a mammalian configuration, with three bones in the ear, and one in the jaw.

Mammal hearing owes its power to the presence of three bones in the ear: the malleus (or hammer), the incus (anvil), and stapes (stirrup). However, reptiles have only the stapes. On the other hand, reptiles have three bones in their jaw, two that make up the jaw joint, and a larger one that holds the teeth.

As mammal-like reptiles evolved, the bone holding the teeth grew larger and larger, until it became large enough to connect directly to the skull. The two smaller bones atrophied and disconnected, but instead of going away completely, they found a role in the inner ear, becoming the malleus and incus.

Even more remarkable, we can see this process being reiterated today in possum young. When they are developing as embryos, these primitive mammals actually have a reptilian jaw configuration, with only one ear bone and three jaw bones. However, as the young mature, they develop a more mammalian configuration, although it’s a process that doesn’t complete until long after they are born.

Still Connected

Although the tiny bones that disconnected from our jawbone millions of years ago are no longer directly connected to the jaw, the jaw now presses against the temporal bone, which houses these tiny bones. Excessive pressure in the jaw joint could lead to pressure on the temporal bone, interfering with the function of these three tiny bones, or disrupting the function of the nerves that carry information from the ears to the brain, causing tinnitus, vertigo, and other ear-related problems.

To learn whether alternative treatment can help your tinnitus, please call (303) 691-0267 at the TMJ Therapy & Sleep Center of Colorado in Denver.