What is Trismus ?

[Extracted from the web page of wisegeek.com]

Trismus, sometimes referred to as lock jaw, is a condition in which an individual suffers from an inability to open his or her mouth to its full extent. It can be caused by a large variety of underlying nerve, muscle or joint complications ranging from surgery or trauma to temporomandibular joint disorder. This condition can last as little as a week or might be of a longer duration, depending upon the cause. The inability to completely open the jaw can occur suddenly or might develop over time. If left untreated, it can lead to a number of other complications, such as a difficulty swallowing, a lack of nutrition and inadequate oral hygiene.
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Trismus often results from damage to the joints, muscles or nerves located in and around the jaw area. It can be caused by any number of other factors and is not a disease in itself, but the result of another underlying problem. Some common causes are pericoronitis, peritonsillar abscess, radiation to the neck or head area or a tumor located in the area of the jaw. The condition also might result from issues as common as a shot of local anesthesia during dental procedures or grinding and clenching of the teeth.

Although the primary indication of trismus is an inability to open the mouth, other symptoms can include difficulty in speech, headaches, pressure or pain around the jaw and trouble chewing or swallowing. Anyone experiencing these symptoms should contact a doctor or dentist to detect the primary problem. An evaluation of the patient’s medical history will be performed in an attempt to uncover the cause. In some instances, diagnostic tests might be needed to detect the underlying problem.

The duration of trismus is largely determined by the cause of the condition. For example, if the onset of the difficulty is because of clenching the teeth or other temporary stretching and contracting of the muscles in the jaw area, then the inability to open the mouth might last only a few days. Trismus that is the result of radiation therapy, infection or trauma might have longer-lasting effects.

The quality of life of individuals who are suffering from trismus can be greatly affected in a number of ways. The condition can lead to an inability to communicate effectively and might make it difficult for the sufferer to chew or swallow. Additionally, individuals might experience varying degrees of pain or discomfort. In severe cases, the inability to open one's mouth can greatly compromise an individual’s overall health by limiting oral hygiene, increasing the risk of aspiration and making it difficult to receive proper nutrition.