Trismus
Pronunciation: TRIZ-mus
Restricted or painful opening of the mouth caused by spasm or fibrosis of the muscles of mastication, often postoperative or inflammatory in origin.
Full Definition
Trismus refers to limited mouth opening, typically defined as an interincisal opening of less than 35 mm in adults, resulting from spasm, inflammation, fibrosis, or direct injury to the muscles of mastication or the temporomandibular joint. In oral surgery contexts, trismus is a common postoperative finding following third molar extraction, particularly when there is involvement of the pterygomandibular space. It can also result from tumour infiltration, radiation fibrosis, or submucous fibrosis. Editors should note that 'trismus' is a noun and that adjectival use ('trismic') is rare; prefer the phrase 'trismus was noted' over 'the patient was trismic.' Do not confuse with ankylosis, which implies bony or fibrous joint fusion.
Usage
Usage note: In clinical notes, trismus should be quantified (e.g., 'interincisal opening of 22 mm'). Do not use 'lockjaw' in formal clinical documentation; reserve for informal contexts. Distinguish from TMJ ankylosis.
In Context
- "The patient reported significant trismus four days post-operatively, with a maximum interincisal opening of 18 mm." — Postoperative clinic note
- "Editors should replace colloquial references to 'lockjaw' with 'trismus' in all formal oral surgery discharge summaries." — Discharge summary editing