How Jaw Joint Popping Is Different from Knuckle Cracking

Aug 27, 2014, by Dr. Becky Coats

For people who routinely crack their knuckles–or know people who crack their knuckles–it might be hard to imagine that your jaw joint popping is actually a serious concern. After all, knuckle cracking seems to cause little damage (though it does cause damage), so why should we be concerned about popping in the jaw?

These are very different phenomena, and, unlike knuckle cracking, jaw joint popping is a sign that something is wrong in your temporomandibular joint.

What Causes Cracking in Your Knuckles

When you pop or crack your knuckles, you’re manipulating them in ways they don’t normally move. Specifically, you are expanding the joint space between the two bones. This joint space is filled with cartilage bathed in synovial fluid. Inside the fluid are gases. As you increase the space in the joint, these gases come out of solution, which is what we believe causes the sound. Or, rather, part of the sound, since the knuckle cracking sound actually has two separate peaks. The other part of the sound is believed to be from the joint capsule reaching the limit of its expansion.

What Causes Cracking in Your Jaw

On the other hand, popping or cracking in your jaw is caused by displacement of the cartilage in the jaw joint. Whereas the cartilage in your knuckles fills most of the joint space and is firmly anchored in place by ligaments, the cartilage in your jaw joint is  much smaller in proportion to the entire joint and is designed to have more freedom of movement to allow your jaw to do the extra motions it needs to perform its complex array of tasks.

When the cartilage gets out of place as a result of TMJ, it sits forward of where it normally does, and though it may be performing its role of cushioning the joint, it’s not in its ideal location. As your joint reaches a certain point, the cartilage will suddenly slip into place, which causes the popping or cracking you hear. You’ll notice that this is normally accompanied by a sudden, irregular motion of the jaw. You may also experience jaw pain, which may be at the moment of the popping, or may be a chronic, dull ache.

Can You Have TMJ without Popping?

Although jaw popping or cracking is a common TMJ symptom, not everyone experiences it. For some people, the cartilage may slip into place without making much in the way of sound. For others, you may have progressed past the point where your cartilage is slipping into place at all. If things have progressed very far, you may notice not a popping sound, but a grinding sound in your joint as the bones are rubbing together. This can result in permanent, irreversible damage to your jaw joint that may require surgery.

You may be tempted to ignore cracking in your jaw, but don’t. It’s a sign that something is wrong and may very well progress to cause permanent damage to your jaw joint. If you are looking for help with a popping joint, please call 817-442-3331 for an appointment with a Grapevine TMJ dentist at Grapevine Dental Care.