The aetiology and pathogenesis of trismus.

The word trismus, from the Greek 'trismos', is defined as a prolonged, tetanic spasm of the jaw muscles by which the normal opening of the mouth is restricted (locked jaw). The designation was originally used only in tetanus, but as inability to open the mouth may be seen in a variety of conditions, the term is currently used in restricted jaw movement regardless of aetiology. As the literature on the subject mainly consists of case reports, the authors have reviewed the pathogenesis, aetiology and management of trismus.