TMJ stands for Temporomandibular Joint, or jaw joint. The TMJs are the two joints in front of each ear. The joints connect the lower jaw (the mandible) to the temporal bones of the skull on each side of the head. The muscles controlling the joints attach to the mandible and allow the jaw to move in three directions: up and down, side to side, and forward and back.

When you open your mouth, the rounded upper ends of the mandible on each side of the jaw (the condyles) glide along the joint socket at the base of the skull. They slide back to their original position when you close your mouth. To keep this motion working smoothly, a soft tissue disc lies between the condyle and the socket. The disc absorbs the shock to the joint from chewing and other movements.

When the mandible and the joints are properly aligned, smooth muscle actions, such as chewing, talking, yawning, and swallowing, can take place. When these structures (muscles, ligaments, disk, jaw bone,  temporal bone) are not aligned, nor synchronised in movement, several problems may occur.

Anatomy of primary masticatory muscles and the temporomandibular joint. Souce: Mayo Clinic 2019

What is TMJ disorder?

Temporomandibular disorders (TMD) are disorders of the jaw muscles, temporomandibular joints, and the nerves associated with chronic facial pain. Any problem that prevents the complex system of muscles, bones, and joints from working together in harmony may result in temporomandibular disorder.

What Causes TMJ Disorders?

Adding to the complexity of TMJ disorders is that there are multiple causes, including cases where no obvious cause can be found. Some known causes are the following:

• autoimmune diseases (in which the body’s immune cells attack healthy tissue)

• infections

• injuries to the jaw area

• dental procedures (even prolonged mouth opening during dental treatment)

• overextending the jaw when insertion a breathing tube before surgery

• medication side effects that increase bruxism,  exacerbate jaw pain, or cause severe jaw damage (e.g. SSRIs used to treat anxiety, OCD, depression and panic disorders, Antipsychotics, ADHD and Parkinson’s Disease medications, and osteoporosis/bisphosphonate drugs)

• various forms of arthritis

• Stress

Additionally, there are genetic, hormonal, and environmental factors that can increase the risk for TMJ.