Trismus, or Lockjaw, refers to reduced opening of the jaws caused by spasm of the muscles of mastication, or more generally to any instance limited mouth opening stemming from a variety of causes. Temporary trismus occurs much more frequently than permanent trismus. It is known to interfere with eating, speaking, and maintaining proper oral hygiene. This interference, specifically with the patient's ability to swallow properly, results in an increased risk of aspiration. In some instances, trismus presents with altered facial appearance. The condition may be distressing and painful for the patient. Examination and treatments requiring access to the oral cavity can be limited, or in some cases impossible, due to the nature of the condition itself.