What Is The Temporomandibular Joint (TMJ) And What Does It Do?

Your Temporomandibular Joint, or TMJ for short, is located in your jaw. It’s an important piece of apparatus and when dysfunctional, can cause considerable discomfort, and affect important activities like chewing, swallowing, and talking.

In this post, we explain what the Temporomandibular Joint is, how it works, what it does, and what can happen to it.

So – What Is The Temporomandibular Joint?

The Temporomandibular Joints are a pair of hinged sliding joints located just in front of your ears on each side of your head. They connect your lower jaw, a freely moving structure, to your skull.

Their job is to allow your jaw to move up and down, from side to side, and open and close.

The joints lie within a protective membrane-lined fibrous capsule. The membrane produces synovial fluid to protect and provide nutrients to the various components within the joint.

The Structure Of The TMJ

The TMJ consists of a shallow dish-like socket (mandibular fossa) on the edge of the temporal skull bone and a rounded knob on the top of your jawbone (mandibular condyle).

A cushioning articular disc sits between them, providing protection and allowing the condyle to slide and rotate in the socket. It also helps distribute synovial fluid throughout the joint.

A group of muscles and ligaments around the joint provide stability and assist its movement.

How Does The TMJ Work?

When you open your mouth slightly, the knob (condyle) rotates in the socket like a hinge. However, the amount of hinge rotation available is restricted so as you open your mouth wider, the sliding mechanism comes into play.

It works as follows:

Ligaments around the articular disc and condyle, engaged when you open your mouth, stretch the front of the disc forward along the sloping side of the socket. This provides a cushion for the condyle to slide along.

As it does, you can utilise the additional leverage to open your mouth more. When you close your mouth again, the disc retracts back into position, allowing the condyle to slide back into the socket.

Your two TMJ joints also work synchronistically so you can rotate your jaw, move it laterally from side to side, and move one side more than the other.

What Can Happen to the TMJ?

A number of things can cause issues in and around your TMJ. These include:

1. Physical problems with the TMJ itself – displacement of the articular disc, arthritic changes, trauma or injury, the strain caused by habitual teeth grinding or clenching (bruxism), birth defects and even tumours, although these are rare.
2. Conditions that affect the ‘masticatory musculature’ in your jaw. That’s a fancy name for the muscle structures responsible for moving your jaw.

What Causes TMJ Pain and Dysfunction?

Any dysfunction in your TMJ is collectively referred to as TMJ Disorder or TMJD. These may or may not be painful depending on the circumstances.

You can develop TMJ dysfunction for various reasons – misalignment, trauma, inflammation, strained muscles, Bruxism, degeneration, poor posture, wear and tear, and even stress and tension.

• Trauma – an injury or impact to your head can misalign your jaw and TMJ, resulting in pain and inflammation.
• Inflammation – injury or overuse can cause swelling and pain in your jaw muscles around the TMJ, and make it hard to move your jaw.
• Strained muscles – Overuse, stress, and even poor posture can strain the muscles around the TMJ, causing pain and dysfunction,
• Teeth grinding (bruxism) – if you have a habit of grinding your teeth or clenching your jaw, this can strain your jaw muscles, and lead to TMJ pain,
• Wear and displacement of the articular disc – the disc acts as a cushion and shock absorber within the joint. If it becomes worn or displaced, this can lead to pain, clicking in the joint, or make it difficult to open your mouth and move your jaw normally. It may also cause your jaw to lock,
• Degenerative changes – osteoarthritis or rheumatoid arthritis can cause deterioration and inflammation within the TMJ.

Interesting points: TMJ disorders affect females more than males, and are more prevalent in people aged between 35 – 44 years, whilst MS sufferers tend to have an increased risk of developing TMJD!

Risk Factors That Can Cause TMJD

Many things can increase your risk of developing TMJD. Chief amongst them are:

• Misalignment – injury, arthritis, bruxism (teeth grinding), or a misaligned bite can cause your TMJ to become misaligned, a major cause of TMJD,
• Poor posture – poor cervical spine posture can affect the alignment of your skull and jaw, affecting TMJ function,
• Stress and muscle tension – tight jaw muscles from stress, clenching your jaw, headaches, or even poor posture can put pressure on your TMJ, resulting in pain, discomfort, and limited jaw movement. This situation can be worsened by headaches and TMJ pain,
• Connective tissue diseases – if you have an autoimmune disease like fibromyalgia or lupus, there is a risk it could affect the connective tissues around your TMJ joint and contribute to TMJD,
• Neurological conditions – some neurological conditions, like Multiple Sclerosis (MS), can increase the risk of developing TMJD because of factors like muscle weakness, jaw clenching, spasticity, or trigeminal neuralgia,
• Gender – unfortunately if you were born female, you’re around 4 times more likely (according to this research) to develop TMJD than someone born male. This may be due to hormonal fluctuations females experience throughout their lives.

What Are Common Symptoms of TMJ Disorder?

TMJ disorder results in a range of symptoms ranging from physical pain to lockjaw, headaches, and hearing problems. The following are among the most common symptoms of TMJ dysfunction:

• Jaw pain in the TMJ and jaw muscles that gets worse when you move your jaw
• Clicking or popping sounds when you open or close your mouth
• Difficulty chewing with pain and stiffness present whilst you’re eating or talking
• Lockjaw is where your jaw gets stuck in a particular position and you can’t move it, or have difficulty moving it
• Headaches in your temples and forehead
• Earaches that feel like an ear infection (caused by the TMJ affecting the Eustachian tube in the middle ear – the TMJ is located adjacent to your middle ear)
• Hearing problems (notably muffled hearing and tinnitus) if the TMJ affects nerve function within your middle ear

What You Can Do To Help TMJD

The good news is that if you have TMJD, there are a few non-invasive and simple ways to help improve the condition.

Jaw Exercises for TMJ Disorders

Work on jaw exercises and physical therapy techniques that target the muscles around your jaw and TMJ to improve flexibility, reduce muscle tension, and strengthen the supporting muscles around the joint.

Changes in Lifestyle

Identify and address factors that may be contributing to your TMJD, or making it worse.

You may for example work on improving your upper body and cervical posture (chiropractic care can help with this) if that’s a risk factor for you. Or concentrate on managing stress in your life that could be creating muscle tension in your jaw, and contributing to TMJD.

Even changing what you eat, and avoiding hard and chewy foods can help improve TMJD.

Develop Good Sleep Habits

Developing good sleep habits i.e. regular sleep schedule, a relaxing bedtime routine, avoiding positions that strain your jaw, and using supportive pillows or mouth guards, can all help reduce TMJ pain.

How Do I Keep My TMJ in Good Health?

• Don’t grind or clench your teeth – consider wearing a mouth guard at night
• Regularly stretch and exercise your jaw to help strengthen and mobilise your jaw and TMJ
• Use muscle and relaxation therapies to help with TJMD symptoms like stress and tension
• Develop and maintain good posture and jaw alignment – regular chiropractic adjustments can help with this
• Make lifestyle adjustments, like avoiding hard and chewy foods, and habits or situations that put a strain on your jaw, along with improved ergonomic choices, to improve your overall musculoskeletal health
• Develop good oral and dental hygiene – regular dental checkups are a good idea. Apply cold or hot therapy to your jaw to reduce inflammation or loosen tight muscles

Conclusion: What Is The Temporomandibular Joint?

Your TMJ allows you to move your lower jaw so you can eat, talk, and open your mouth. It can also be subjected to a range of situations that hamper its effectiveness – from muscle tension to poor posture, injuries and even some types of medical conditions.

These can result in pain and inflammation. However, by developing some good habits, you can keep your TMJ healthy and functional, and minimise the effects of TMJD.