Syndrome, TMJ: Disorder of the temporo-mandibular joint (TMJ) causing pain usually in front of the ear. Pain in the TMJ can be due to trauma (such as a blow to the face), inflammatory or degenerative arthritis, or by the mandible being pushed back towards the ears whenever the patient chews or swallows. Sometimes, muscles around the TMJ used for chewing can go into spasm, causing head and neck pain and difficulty opening the mouth normally.