A recent study sheds further light on the link between temporomandibular dysfunction (TMD) and restricted range of motion (ROM) in other parts of the body.

The study’s subjects with complex regional pain syndrome (CRPS) experienced a significant increase in ROM of the hips following one session of myofascial release of the temporomandibular joint (TMJ).

The research, “Influence of the Temporomandibular Joint on Range of Motion of the Hip Joint in Patients with Complex Regional Pain Syndrome,” involved 20 participants with CRPS, along with 20 healthy subjects, who served as the control group.

The study’s authors describe CRPS as a complication following trauma or surgery, with symptoms that include a severe neuropathic deep pain in the involved limb with distal accentuation and brush-evoked pain. The authors also report reduced ROM, particularly in the hip joints, is another common symptom of CRPS.

Inclusion criteria for the CRPS group were a diagnosis of CRPS and pain lasting more than three months. Exclusion criteria were a diagnosis of osteoarthritis, fibromyalgia, fever or respiratory decompensation. For the CRPS subjects, the dominant pain complaint was the hand or foot, but pain in other parts of the body also was reported as frequent.

Subjects in both the control group, composed of healthy adults, and the CRPS group experienced the same intervention and evaluation process.

Hip ROM was measured three times for each subject in the study. The first measurement took place before myofascial release of the TMJ, to establish baseline data.

The second hip ROM evaluation took place after myofascial release of the TMJ, which involved “traction applied to the mandible in an anterior-distal direction for 90 seconds at the barrier of joint play,” according to researchers. During this portion of the study, participants were instructed to keep their legs flat on the table and not to speak, bite or swallow.

The third evaluation of hip ROM happened while each subject clenched his or her jaw, to stimulate dysfunction of the TMJ.

Results of the research revealed that the pattern of femoral angles was the same in both groups, with the first hip ROM measurement always slightly higher than the third, indicating greater restriction in the hips, and the second measurement—following myofascial release of the TMJ—always lower than both the first and the third.

However, this difference was far more pronounced in the CRPS group, with a much more significant improvement in hip ROM following TMJ myofascial release.

“Our study indicates that myofascial release in the jaw does improve hip abduction, although we do not know how long this effect lasts,” state the study’s authors. “The results suggest that TMJ dysfunction plays an important role in the restriction of hip motion experienced by patients with CRPS, which indicates a connectedness between these two regions of the body.”

Authors: Michael J. Fischer, Kathrin Riedlinger, Christoph Gutenbrunner and Michael Bernateck.

Sources: Department of Rehabilitation Medicine, Department of Anesthesiology, Pain Clinic, Hanover Medical School, Hanover, Germany; Department of Neurology, Friedrich Baur Institute, Ludwig Maximilians University, Munich, Germany. Originally published in Journal of Manipulative and Physiological Therapeutics (2009) 32:364-371.