Causes for the altered or disturbed movement include direct or indirect macrotrauma (eg, flexion-extension injury of the neck—also known as whiplash—which can cause referred pain), microtrauma (eg, due to parafunctional behaviors such as awake / sleep clenching and grinding of the teeth or persistent gum chewing), systemic disorders (eg, rheumatoid arthritis or other autoimmune / connective tissue disorders), local or systemic infections, and acute malocclusion.