Temporomandibular Joint Dysfunction (TMJ): Definition & Causes

Instructor: Alyssa Campbell

Alyssa is an active RN and teaches Nursing and Leadership university courses. She also has a Doctorate in Nursing Practice and a Master's in Business Administration.

The temporomandibular joint, also known as the TMJ, is the joint that connects the moving piece of the jaw with the rest of the skull. Read this lesson to learn about TMJ dysfunction, which frequently leads to pain, clicking, and other symptoms in these joints.

TMJ Definition

Over the past year or two, Charles has had increasingly more pain and soreness just in front of his ears, at the point where the jaw bone connects with the skull. He makes an appointment with his family doctor to investigate the cause of this pain.

Charles' doctor explains that because the jaw bone helps to create the pressure needed to open and close mouths, bite, and chew our food, enormous amounts of physical stress are placed on these joints.

The temporomandibular joint (TMJ) is the joint connecting the mandible, or jaw bone, to the rest of the skull. People have two TMJs, one on each side of the jaw, that help the jaw act as a hinge. These joints act as pivot points to allow people to bite, chew, and speak. Aside from natural wear and tear on these joints, other conditions and trauma can create issues leading to TMJ dysfunction.

Related Issues to TMJ Dysfunction

TMJ dysfunction is a serious condition because it leads to many uncomfortable symptoms. Charles learns that while TMJ dysfunction is abnormal, it is pretty common. Other people with symptoms of TMJ dysfunction may also present with:

  • Pain: occurs after intended or unintended pressure on the jaw.
  • Headaches: due to clenching or difficulty chewing.
  • Jaw popping: occurs when the jaw moves to open the mouth, creating a clicking or a popping sound.
  • Facial swelling: may happen as a result of dislocation or infection.
  • Jaw stiffness: creating difficulties chewing and safely swallowing food, along with difficulty speaking.

Causes of TMJ Dysfunction

While the doctor conducts a physical assessment of his jaw, he asks Charles a few questions to help determine the cause of his TMJ pain and discomfort. Even though more scientific research is needed to understand the true causes of TMJ dysfunction, finding an obvious cause may help to correct the problem and bring some relief to Charles' ongoing symptoms.

Natural Causes

The doctor has Charles open his mouth to inspect for any tooth abnormalities, and asks him to bite down to assess his bite pattern (the way that a person brings their teeth together to bite down), as any issues noted here may cause significant strain on either or both TMJs.

Next, the doctor asks Charles if there is any past medical or family history that may indicate arthritis (swelling and painful joints), or any muscular disorders that would contribute to his TMJ dysfunction.


When the assessment is completed, the doctor asks Charles about any trauma, or injury, that may have caused the pain. Charles denies any recent or past injury to his face and his jaw.


During his assessment, Charles is asked about his level of stress. Charles shares that ever since he started his new job, he has been increasingly more stressed. When the doctor asks when the new job started, the timeline matches up with when Charles began to notice the pain.

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