Microstomia
Pronunciation: my-kroh-STOH-mee-uh
An abnormal reduction in the size of the oral aperture, limiting mouth opening and access to the oral cavity, commonly associated with systemic sclerosis or scarring.
Full Definition
Microstomia describes a pathological narrowing of the oral opening, which impairs speech, mastication, dental treatment access, and intubation. It arises most frequently in systemic sclerosis (scleroderma), extensive burns, epidermolysis bullosa, and post-surgical or post-radiotherapy scarring. In oral medicine manuscripts, microstomia should be distinguished from trismus, which specifically denotes restricted mouth opening due to muscular or temporomandibular causes rather than perioral tissue constriction. Quantitative measurements of the interincisal distance in millimetres are standard when documenting microstomia severity. Editors should confirm that numeric thresholds used to define 'microstomia' are cited to a source.
Usage
Usage note: Do not use interchangeably with 'trismus'. Microstomia refers to perioral tissue restriction; trismus refers to muscular or TMJ restriction of jaw opening.
In Context
- "Progressive microstomia had reduced the patient's interincisal distance to 18 mm, severely limiting dental access." — Oral medicine clinical record
- "The author used 'microstomia' and 'trismus' interchangeably; the editor inserted a query distinguishing the perioral tissue aetiology of microstomia from the muscular aetiology of trismus." — Manuscript editing query