There seems to be some common misconceptions regarding the term “lockjaw.” On the one hand, many TMD sufferers will complain of a condition they call lockjaw. On the other hand, there is a serious medical condition that is also popularly called lockjaw that has nothing to do with TMD at all. Let’s examine both to determine the differences between them.
Jaw Stiffness With TMJ Disorder
Some TMD patients experience a painful condition in which their lower jaw will seemingly “lock” in place, or get stuck, making it very difficult to try to open or close the mouth without a lot of pain. A lot of people call this lockjaw, but it’s not. And for many TMD sufferers, this comes on suddenly and randomly, with no warning or pattern of behavior to cause it.
There are several causes for this jaw stiffness with TMD. Generally, the muscles of the face, neck, and jaw area can become inflamed and irritated by poor bite, causing them to tighten. This tightening of the muscles attached to the jaw joint can create the locking, or stopping, of the jaw. The joint can’t function properly because the muscles aren’t functioning properly.
For some, the problem can be with the jaw joint itself. The jaw joint is capped by an articular disc—a band of cartilage that acts as a cushion between your jaw bone and your skull. The cartilage can become damaged or even torn by repeated clenching of the teeth and tightening of the muscles around it. It can also become damaged or torn in an injury. When damaged, it can slip to the front, side, or back of the bone. Slipping to the front or side causes a painless “popping” when the jaw is opened. However, if it slips too far to the front, it can bunch up, creating a mass of tissue in the way. This causes the joint to become locked, or frozen, in place, because the disc is preventing it from functioning to full range. This is a painful condition that often requires medical treatment to alleviate.
Tetanus and Lockjaw
There is a bacterial infection known as tetanus—yes, the stuff you can get from a rusty nail or tin can—that can cause muscle spasms, including those of the face and jaw. It is a serious illness and can even be fatal. Because of the muscle spasms associated with the illness, many people in years past referred to it as lockjaw. Tetanus, however, is a far cry from TMD, and is pretty much a thing of the past now that tetanus vaccines are a routine part of health care. So, while tetanus can cause, and is even called “lockjaw,” it is a far more serious and acute condition than TMD, and fortunately far less common than the problems seen with a poor bite leading to poor function in the jaw.
When Lockjaw is NOT Lockjaw
As we’ve seen, both TMD and tetanus have a tradition of being called lockjaw. However, as we’ve also seen, neither is truly the case. In TMD, the condition in which the jaw locks or sticks in position is medically known as jaw lock, not lockjaw. And tetanus, while having been known for years as lockjaw, is a serious bacterial condition that involves much more than just the tensed up muscles of the face and mouth.
So, I suppose we could safely say that neither TMD nor tetanus should be referred to as lockjaw. But if you suffer from TMD jaw lock, now you know how to properly refer to it when speaking with your doctor or dentist, who if they have the training in neuromuscular dentistry can remedy the problem. Like so many times, when you hear hoof beats, look for horses and not zebras. If you have problems with the function of your jaw and bite, a well-trained Neuromuscular Dentist may well be your best first step.