Trismus, often called "lockjaw", is hypomobility of the mouth, i.e. where you have a restricted and limited range-of-motion of the mouth. Trismus has a variety of causes, and can occur from nerve, muscle, or joint problems. Trismus or lockjaw is an early symptom of tetanus, but is most frequently caused by other conditions. Trismus is often associated with difficulty swallowing (dysphagia).
The negative of effects of trismus include difficulty speaking, eating, drinking, coughing, sneezing, and maintaining oral hygiene. These are serious quality of life issues that require significant attention, and overlooking them can lead to malnutrition, dehydration, social disorders, addiction, and muscle/joint degeneration.
Common causes of trismus include: TMJD, burn scars, radiation treatment to the jaw and head, arthritis, scleroderma, fibromyalgia, trauma, infection, impacted wisdom teeth, psychological conditions including stress, bruxism and grinding, congenital conditions, and other muscluloskeletal conditions.
Trismus can occur as a chronic long-term symptom of a broader condition, like arthritis or scleroderma, or as a unique and reversible condition. Treatments are generally the same, however chronic sufferers will need to maintain treatment for continued relief.
Unfortunately, the lack of motion from trismus can allow the joint to degrade, making movement even harder. Treating trismus early can prevent severe joint damage, and provide significantly improved quality of life. Degeneration of joint tissue has been shown in as little at 3 days of joint immobilization, with thinning cartilage and increasing viscosity of the synovial fluid.