Is TMJ the most complex joint in the body?

[jk5177]

I heard someone posting it as the most complex joint, and I just couldn't believe it. Perhaps I haven't studied it in depth, but TMJ seems like a simple hinge joint to me. The shoulder, help, or even the knee joint seems more complicated.

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[LSR1979]

I heard someone posting it as the most complex joint, and I just couldn't believe it. Perhaps I haven't studied it in depth, but TMJ seems like a simple hinge joint to me. The shoulder, help, or even the knee joint seems more complicated.

While there is no quantitative way to determine which joint is the most complex, it is pretty much agreed that the TMJ is just that. It is not at all a hinge joint, if it was you would not be able to get the lateral movements that you get as well as the protrusion and detrusion of the mandible. The joint actually has two main movements - rotation and translation. On top of this, each side moves independently of the other. The complexity of this joint is immense and requires years of OMFS training to really become familiar with diagnosing the pathology of TMD. Anyways, lots of literature exists about its anatomy and function. Read up on it.

 

[toofache32]

The shoulder, help, or even the knee joint seems more complicated.

...based on what?

I don't think there is an answer to this question.

 

[jk5177]

Thanks. As I was reading your post, my TMJ was moving to confirm what you are saying. I'll be reading up on it.

 

[txdent2be2007]

... but TMJ seems like a simple hinge joint to me.

The TMJ is a compound joint classified as ginglymoarthrodial -- this means it acts both as a hinge (ginglymus) and sliding (arthrodial) joint. You can see this yourself when you open slowly, placing your fingers over your mandibular condyles just ant. to your ears. The first part of the movement (I think I remember this as 1/3 of the arc?) is purely rotation, while the remaining motion up to maximum opening is sliding/translation. You can look at any anatomy book with a sagittal section through the joint capsule to see the anatomic reasons for this movement.

This is a VERY superficial treatment of a very complex joint -- OMS's spend years learning how to deal with the physiological and psychological problems that patients experience with their TM joints.

 

[aphistis]

...based on what?

I don't think there is an answer to this question.

Nobody will ever agree on a question like this, but you could make a pretty solid argument in the TMJ's favor. It rotates freely in all three planes just like any ball & socket joint, but I don't know of any other joints that share its ability to translate.

 

[Literati81]

The temporomandibular joint is by far the most complex joint in your body for the reasons listed above. In addition, the dire ramifications of TMJ damage are further complicated by various inadequacies in TMJ research, dx, tx and management.

Currently, here are over 50+ treatments for TMD that range from conservative splint therapy to irreversible surgery; none of the treatments have been supported by the ADA nor AMA. The biggest problem with TMD is determining the cause. Most doctors/dentists make the haste assumption that stress and anxiety is the major contributing factor, meanwhile ignoring literature and patient histories which point at joint disease (e.g. osteoarthritis, rheumatoid arthritis), genetic factors, poor dental work/orthodontics, trauma, malocclusions, etc. TMD is poorly understood and creates painful manifestations in the jaw as well as it's associated muscles. Thus making daily activities such as talking, eating, chewing and laughing very difficult.

According to the NIH, nearly 11 million people in the US suffer from TMJ problems at any given time. Oddly nearly 90% of them are women. Unlike your knee or hip joints, implants/surgical replacements have been unsuccessful; many patients who opted for Vitek implants in the 80s (the so-called "TMJ cure!") had problems such as facial paralysis/disfiguration, bone deterioration, weakened immune system, etc. After seeing the consequences, the FDA banned Vitek in the 90s. Yet, by that time, nearly 26,000 Vitek implants were sold to oral surgeons. As for the "malocclused"-TMJ patients, orthognathic surgery has shown little success in subsiding TMJ pain. Many patients are talked into performing surgery to alleviate their TMJ pain yet end up as life-time surgical cases with additional problems.

So is TMJ a complex joint? I believe so. I probably went far beyond the OP's inquiries. I apologize. I just find TMD fascinating.

And, one question...
Is there any other residency/specialty other than OMS where one could learn more about TMJ? According to literature, surgery has been unsuccessful in many cases and is often considered the last option. So, I would find it odd if there was only one (pro-surgical) route supplied by academia.