—Alisa, Los Angeles, CA
Tias Little's reply:
The temporomandibular joint (TMJ) often freezes from extensive dental work, a blow to the cranium, or a high-stress lifestyle. Know that you are not alone, that it is very common for people to have debilitating locking in the jaw.
The best pose to begin releasing the TMJ is seated meditation. Here, there is an opportunity to practice releasing the tension locked into your jaw. Start in a comfortable seated position for meditation and focus on relaxing your tongue (often the tongue will relentlessly cling to the roof of the mouth). Deeply relax your tongue, your eyes, and observe that your lower and upper teeth move slightly away from each other. Soften the skin at the corners of your mouth. These directions are the beginning stages of the practice of pratyahara—the internalization of sensory awareness.
Decompressing your jaw this way takes practice. Bring this practice into your everyday life and be attentive to relaxing jaw strain while driving, listening to a co-worker, and getting things done. Do this practice of emptying strain out of your jaw all the time, day after day.
Asanas such as the Adho Mukha Svanasana (Downward Facing Dog) bring blood flow into your cranium, bathing the TMJ in blood and lymph. Practicing the vinyasa (Upward Facing Dog into Downward Facing Dog) serves to flush blood in and out of the jaw and face. Salamba Sarvangasana (Shoulderstand) or Viparita Karani (Legs-Up-the-Wall-Pose) will also send ample blood into this area, again bathing the joint in much-needed fluid. You may wish to avoid Salamba Sirsasana (Headstand) altogether as it can tend to put even greater pressure on the TMJ.
Finally, the key is to breathe. Loosen the lock on your jaw and relax in the face of all activity!