What is TMJ Dysfunction
- Carolyn Khoo
- Jan 27
- 3 min read
What Is TMJ Dysfunction?
TMJ refers to the temporomandibular joints. You have two, one on each side of your jaw.
They connect the lower jaw to the skull and play a role in chewing, speaking, yawning, swallowing, and breathing. These joints work alongside a complex network of muscles, ligaments, and nerves.
TMJ Dysfunction - also known as TMD - occurs when this system stops functioning smoothly.
Importantly, research consistently shows that muscle related TMD is the most common presentation, rather than damage to the joint itself. Large population studies using recognised diagnostic tools show that muscle related jaw pain is the most common form of TMJ Dysfunction, far more common than joint damage.(https://doi.org/10.1016/j.jdent.2014.01.002)
Pain is common, but not universal.Some people experience tightness, fatigue, limited movement, or joint noise without clear pain. This variability is one of the reasons TMD is often missed.
Do I Have TMD? Simple Checks That Offer Clues
These checks are not diagnostic tools.They are observational markers commonly used in clinical screening.
The Three Finger Test
Insert your middle 3 fingers vertically inside your oral cavity. A normal, comfortable mouth opening is typically around 40 to 50 mm. In practical terms, this often equates to fitting three fingers vertically between the teeth.
Reduced jaw opening is frequently reported in people with TMD, particularly in muscle driven cases (https://doi.org/10.1111/j.1365-2842.2009.02009.x). Difficulty performing this test does not confirm TMD, but it suggests that jaw mobility may be restricted.
Sounds and Sensations
Clicking or popping, grinding or clenching. A feeling of the jaw catching or shifting
Joint noise alone is common and not always pathological. However, when combined with pain or movement restriction, it becomes more clinically relevant (https://doi.org/10.1016/j.jdent.2017.01.012)
Pattern Recognition
Pain worse in the morning, headaches starting near the temples, symptoms flaring during stress, ear fullness with no infection.
TMD symptoms often follow patterns linked to load and stress, rather than appearing randomly. This aligns with evidence showing strong associations between TMD, parafunctional habits such as clenching, and psychosocial stressors (https://doi.org/10.1016/j.jpain.2010.01.002).
Conditions That May Actually Be TMD
One of the biggest challenges with TMJ Dysfunction is how well it mimics other conditions.
Research shows significant overlap between TMD and tension type headaches, migraines, neck and shoulder pain, otological symptoms such as ear fullness or tinnitus.
The trigeminal nerve, which supplies the jaw, also plays a role in facial pain and headache pathways. This neurological overlap explains why jaw dysfunction can present as head or ear symptoms (https://doi.org/10.1016/j.neuro.2008.02.014).
Studies have also demonstrated a strong association between TMD and cervical spine dysfunction, reinforcing the link between jaw mechanics and neck pain (https://doi.org/10.1016/j.jelekin.2015.06.003).
This does not mean other diagnoses are wrong. It means the jaw is often not assessed as part of the picture.
Why TMJ Dysfunction Is So Often Missed
TMD sits between disciplines.
Dentistry often focuses on teeth and bite.
Musculoskeletal care may focus on the neck and shoulders.
Neurology may focus on headaches.
Because TMD crosses all three, responsibility is fragmented.
Add to this the growing evidence that stress, nervous system dysregulation, and psychosocial load significantly influence TMD severity and persistence, and it becomes clear why short term or isolated treatments rarely hold (https://doi.org/10.1016/j.jdent.2013.06.004)
What To Take From This
This is not about self diagnosing. It is about recognising patterns.
If pain or tension keeps returning in your jaw, temples, ears, neck, or shoulders, TMJ Dysfunction may be contributing.
Understanding that connection is often the first step towards effective, long term management.
In the next post, I will explore the question I hear most often.
And what that word realistically means when it comes to the jaw.
If you would like book a TMJ Intra Oral treatment with us, please click on one of the below:
References
Manfredini D et al. Epidemiology of temporomandibular disordershttps://doi.org/10.1016/j.jdent.2014.01.002
Dworkin SF et al. Diagnostic criteria for temporomandibular disordershttps://doi.org/10.1111/j.1365-2842.2009.02009.x
Slade GD et al. Painful temporomandibular disorder prevalence and risk factorshttps://doi.org/10.1016/j.jpain.2010.01.002
Piovesan EJ et al. Trigeminal mechanisms in headache and facial painhttps://doi.org/10.1016/j.neuro.2008.02.014
Silveira A et al. Relationship between temporomandibular disorders and cervical spine dysfunctionhttps://doi.org/10.1016/j.jelekin.2015.06.003
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