When we think of joints, we usually think of two types, a hinge, like the knee, or “ball and socket,” like the hip. It makes intuitive sense that these weight-bearing joint spaces would get “compressed” over the years, resulting in arthritis pain and possibly meniscus or joint replacement surgery. Similarly, we understand arthritis in the fingers – that repetitive grasping and squeezing actions of the hands contract joint spaces as we age, especially for people with physical jobs.
But the temporomandibular joint (TMJ) does not fall neatly into these categories. Its location and mechanics presents barriers to “routine” joint treatment for pain sufferers – they can’t open just one side of the jaw to allow the other side to recover and they can’t use braces or physio tape to support the joint and reduce pain. What causes the TMJ to lose space to the point of compressing the joint cartilage (clicking) and eventually joint destruction (arthritis), often before other joints? What causes the TMJ to be so randomly symptomatic despite good adherence to soft foods, bite guards, and jaw exercises?
By virtue of the compact anatomy, the TMD’s relationship with “cranial” disorders such as headache, vertigo, tinnitus, hearing loss, and ear pain, has been easy to accept, but its association with myofascial pain in other body regions has been puzzling for decades. Fortunately, over the last 20 years, growing recognition of fascia as a unifying body organ has prompted disciplines such as physiotherapy and sports medicine to bring a whole-body perspective to the research.
In 2000, one study showed that improving postural alignment as part of TMJ self-care instruction significantly reduced TMD (and neck) symptoms. Other studies noted that certain postural faults correlated very highly with TMD, such as head position and pelvic tilt.
TMJ and the SCM
One innovative 2014 study reduced TMJ and neck pain by taping trigger points in the sternocleidomastoid (SCM) muscle, in recognition of its key roles in posture-maintenance and co-contraction for the jaw (affecting TMJ range of motion).
This concept of SCM “tightness” from its postural duties affecting the TMJ seems almost straightforward since this study explained its direct functional role as an adjacent structure, but how could pelvis position be related to TMD?
Knee Hypermobility and TMD
Human cadaver dissections are finding structural connections in the anatomy that support the existence of myofascial chains that connect a span of body regions. In her groundbreaking book, Functional Atlas of the Human Fascial System (2015), Dr. Carla Stecco reports that one of our fascial layers, the Superficial Fascia, is continuous from the thigh to the neck.
Dr. Stecco’s discovery confirms my own clinical experience of the thigh-neck connection, as I have treated TMD by releasing the thigh and teaching improved postural transition mechanics. Every symptomatic TMD patient I have encountered also had more severe knee hypermobility on the same side as the more painful TMJ. Studies have confirmed an association between TMD and patients with joint hypermobility syndromes such as hypermobility-type Ehlers Danlos Syndrome (hEDS).
As explained in the last article, Genu Recurvatum (knee hypermobility) patients have faulty biomechanics that yield stiff front thigh muscles. Due to its size and role in posture and ambulation, stiff thigh fascia may have a significant pathological role in hypermobile patients.
If you are struggling with chronic TMD and related symptoms, consider if you could have joint hypermobility and start working on your knees. ~