The temporomandibular joint, or TMJ, is the “hinge” that allows your mouth to open and close, and you have one on each side of your head. Here’s what a healthy, functioning TMJ looks like:
If these joints get damaged or misaligned due to trauma or habits of clenching, grinding and bruxing, the result is pain – starting in the jaw and, if left untreated, cascading into the head, neck, shoulders and back. This pain and associated symptoms are part of what is more properly known as TMD, or temporomandibular disorder (or dysfunction).
Here are a few more videos showing what a damaged, dysfunctional TMJ can look like: