Trismus
Pronunciation: TRIZ-mus
Reduced or restricted opening of the mouth due to spasm or fibrosis of the masticatory muscles.
Full Definition
Trismus refers to a reduced maximal interincisal opening, most commonly caused by spasm of the muscles of mastication, infection, trauma, radiation fibrosis, or post-injection complications. In editorial contexts it appears in oral surgery, oral medicine, and oncology-dentistry reports. Editors must distinguish it from ankylosis, which involves joint or bony fusion rather than muscular restriction. The condition is clinically significant in treatment planning because it limits access for dental procedures. Normal mouth opening is generally accepted as greater than 35–40 mm interincisally.
Usage
Usage note: Do not conflate with 'lockjaw,' which in lay usage specifically implies tetanus; use 'trismus' in clinical copy.
In Context
- "The post-radiotherapy patient presented with trismus, limiting interincisal opening to 18 mm." — Oral medicine case report
- "Editors should note that trismus is a clinical sign, not a diagnosis in itself, and the underlying aetiology must be specified." — Editorial style guide note