If you haven’t spent years studying the temporomandibular joint and its disorders, it’s pretty easy to take the joint for granted. You might imagine that it’s like many of the other joints in your body, but that’s where you’d be wrong. The temporomandibular joint is special, which gives us both its amazing functions and its vulnerability to temporomandibular joint disorders (TMJ or TMD).
Let’s take a moment to appreciate why the temporomandibular joint is different from every other joint in your body.
It Works As a Pair
All joints in our body and the muscles that move them are designed to work as a team, but no pair of joints are designed to work like your two temporomandibular joints. Nowhere else in your body are there there two joints that are designed to work together in concert like these ones. Think about it: you can move your elbow without moving your shoulder, and if you’re skilled you can even move one joint in a finger without disturbing the other two. But try to move just one temporomandibular joint and you’ll find it’s impossible.
This paired function is the reason why imbalances and irregularities on one side automatically translate to compensatory mechanisms on the other side.
It Has Its Own Special Movement
No other joint in the body moves like the temporomandibular joint. When people want to put a fine point on it, they sometimes classify it as a “ginglymoarthrodial” joint because it has both hinge (ginglymus) movements like your elbow and sliding (arthrodial) movements like your wrist, but even this doesn’t capture the full range of motion possible in your jaw joint, which might be a little more similar to the combination of a ball-and-socket like your shoulder and a sliding joint like your wrist.
It’s Structured Like Two Joints
In most joints, there’s a single fluid-filled cavity, called the synovial cavity, that surround the entire joint. But in the temporomandibular joint, the articular disk actually divides the joint in half, with two separate synovial cavities, one on either side of the disk.
This helps the temporomandibular joint move as if it’s two joints–it kind of is two separate joints, only instead of having a bone between them, there’s an articular disk. So, really, when we talk about your two temporomandibular joints working together, it’s almost as if it’s four joints that have to work in perfect harmony.
The Disk Is Special
Another special aspect of the temporomandibular joint is the disk itself. In most joints, the bones are coated with a soft, smooth layer of hyaline cartilage, and the disk between the bones is made up of tough, fibrous cartilage. But in the temporomandibular joint, the disk is actually made up of hyaline cartilage on the inside with a layer of tough, fibrous cartilage on the outside. This hybrid structure gives the disk a combination of toughness and flexibility.
Location, Location, Location
And, as much as we’ve talked about the joint itself, we have to keep it in context. The temporomandibular joint is in a unique location at the crossroads of the body, where an unequalled number of blood vessels, nerves, and muscles have to share space with a complex configuration of bones and your airway.
TMJ Is Unlike Other Joint Problems
So when we understand just how truly special the temporomandibular joint is, it only makes sense that TMJ should be unlike other joint disorders, both in the type and range of symptoms, and in their distribution.
And it makes sense that TMJ treatment will be special, too, and administered by a dedicated professional or team of professionals who are dedicated to understanding and treating the problems of these unique joints in the body.