Joints of the jaw (or temporo-mandibular joint) and muscles of the jaw we can chew, swallow, talk and yawn. If the joints and muscles are not functioning normally, you may have a problem temporomandibular (PTM).
Symptoms of MNCs are:
* Pain or tenderness in the joints or muscles attached to the jaw, which may increase upon awakening, to clench teeth during chewing or yawning.
* Difficult to open and close the jaw completely, blocking the jaw open or closed.
* Unexplained headaches or neck pain. These symptoms are attributed to other causes, but sometimes they are caused by MNCs. Talk to your dentist and your doctor.
* Crackling, grinding or clunk by chewing or yawn; strange noises in the joints as a crack or a clunk in opening the mouth, or a crack in grinding or chewing.
The causes and effects
It may involve the MNCs to various factors - including stress - but the cause dece problem is not always obvious. Here are some situations that can cause PTM: 
* The tightness of muscles and grinding of teeth. The tightness can cause muscle pain. Some people are brought to tighten the muscles of the jaw and grinding teeth under stress.
* Injuries to the face or jaw, a fracture of the jaw, a dislocation of the joint and severe brain damage (blow to the neck) may lead to MNCs.
* Certain diseases (eg rheumatoid arthritis) may affect the articulation of the jaw and muscles.
* A lack of growth or development of the jaw can affect the alignment of teeth and cause problems and occlusion and difficulty chewing, which could create a PTM.