You are not alone on this one. Jaw pain is quite common. Up to 15% of US adults have jaw pain or restriction, and it as at least twice as common in women as it is in men. I will write more on why that is in a future post. It is most common from ages 20 to 40. Sometimes we know why we have it, let’s say we had mountain bike crash without a full face helmet. Sometimes we have no idea at all, like the time I had a severe toothache and went in to the dentist, only to find out my tooth was just fine and the pain was radiating from my jaw. That was an expensive lesson. More on common causes below.
What is TMJ?
TMJ stands for your temporomandibular joint. It is where your temporal bone (that part of your skull above your ear) articulates with your mandible (your jaw). It’s a really interesting joint. It has an articular disc, like the ones you have in your spine between vertebra. The disc is biconcave (indented in the middle with thicker ends). The joint movement is also unique because it does both hinging and gliding. Put your hands on the space in front of your ears and press in. Now start to slowly open your mouth. You will first feel the jaw hinge open, and as you continue to open you will feel the jaw glide forward. The jaw can also move side to side (think chewing) and retract (pull in towards your neck, think making an overbite). Numerous muscles and ligaments connect to the jaw to guide it through these motions and stabilize it. The most commonly addressed muscles in jaw dysfunction are the temporalis, masseter, lateral pterygoid, medial pterygoid, and sometimes the digastric muscles.
What is TMD?
TMD or TMJD is the term we use for temporomandibular joint dysfunction, as in pain in the TMJ or restriction in normal movement. You’ll know if you can’t close your jaw all the way as this drastically affects eating and likely speech. Are you restricted in jaw opening? One way to check is to see if you can fit three knuckles in your mouth. Obviously not all knuckles are the same size, but it is a good estimate. You may also have pain just in front of your ears, and sometimes it feels like the pain is in your ears, or you may have a headache across your temple. Another sign of TMD is popping or grinding with jaw opening or closing.
What causes TMJ pain or dysfunction?
Trauma is one cause of dysfunction. Not surprisingly, a right hook to the jaw can derange the joint, a whiplash type injury can affect it, as can repetitive trauma. I have had intense jaw pain the day after chewing through some very dry jerky. One of the most common causes of jaw pain is clenching or grinding the teeth (bruxism). Many who clench their teeth don’t realize they do so. With extra stress of this past year, likely more of us are clenching our jaws. I often wake up with my jaw clenched these days. The three-knuckle test is a good one for testing muscle tightness that may result from clenching.