At CDABC Conference in Richmond..look out for these patients as I will need them for research at UBC in January
November 29th, 2013
Talking about why one TM joint can develop a click.
According to American Academy of Craniofacial pain there are 3 factors that make the TM JOINTS unique.
1. There are two joints, connected by mandible. Therefore one cannot move one joint without moving the other. So if you see a jaw deviating to one side during opening, it is possible to have a problem in one side which progresses over time to have symptoms expressed in other side.
In this slide, the jaw is deviating to right which means the left TM JOINT could develop hyper mobility in form of a click on opening. This needs treatment as high risk for closed lock if mouth has to be open wide a long time.
2. As far as survival part of brain is concerned,tooth position has priority over joint position so we can eat and swallow. This means that the TM Joint is forced by muscles to move so that the teeth will fit together optimally. This can cause a disc displacement and muscle spasm.
3. Arthrokinematically the TM JOINTS have two basic movements.The condyle rotates on underside of disc for first 15-25mm and then the condylar head and disc translate together down Glenoid fossa of cranium to open to normal range of 45-55mm.
If only 40mm can be muscle problem. If 35mm or less could be disc displacement. Easy way to test self is a very comfortable 3 fingers intercisor.
Clinically I find a patient can have a disc issue on one or both sides depending on which muscles win tug of war on mandible.