TRISMUS

Abstract

This chapter focuses on the causes and diagnosis of trismus. Trismus, or lockjaw, signifies a maintained muscular spasm tending to closure of the jaws so that the mouth cannot be opened. The term does not include mechanical inability to open the jaws owing to affections such as mumps, alveolar abscess with surrounding inflammatory edema, injury, Ludwig's angina, quinsy or severe tonsillitis, an odontoma, epithelioma of the mouth, myositis ossificans, and cervicofacial actinomycosis. There are two conditions that may not at first sight be obvious, but may lock the jaws together and simulate true trismus—impaction of a wisdom tooth, and arthritic changes in the temporomandibular joint. These are diagnosed by careful local examination of the teeth and of the joint respectively; in the latter case there may be arthritic changes in other joints also. X-ray examination may be required to detect the joint changes or the impacted wisdom teeth. Circumstantial evidence will generally serve to distinguish trismus because of hysteria or to facial neuralgia; any doubt at first experienced is dispelled if the patient is watched for a while.