title: The Heister mouth gag or 'speculum oris'.
abstract: The Heister mouth gag is attributed to Lorenz Heister, an eighteenth century German surgeon. There is no evidence that Heister designed the mouth gag, the earliest known illustration of which is in the 1719 edition of Heister's Chirurgie. In the first half of the twentieth century, the Heister gag was widely available for use during anaesthesia. It is now rarely used by anaesthestists, but occasionally used by surgeons during oral surgery.
authors.affiliation: Mildura, Victoria.
authors.forename: R P
authors.initials: RP
authors.lastname: Haridas
mesh_terms: D000776:Anesthesiology / Q000266:history* / Q000295:instrumentation*; D004867:Equipment Design; D005858:Germany; D049671:History, 18th Century; D049672:History, 19th Century; D049673:History, 20th Century; D006801:Humans; D013515:Surgery, Oral / Q000266:history* / Q000295:instrumentation*; D013525:Surgical Instruments / Q000266:history*
keywords: Heister mouth gag; anaesthesia; oral surgery; speculum oris