Other Talks in the Series: Oral & Maxillofacial Medicine

Hi, my name is Tara Renton, I'm a professor of Oral Surgery at Kings College London. And I'd like to thank Professor Crispian Scully for the invitation to undertake an HST talk specifically looking at Trismus. The outline of the talk is shown here on this slide.
Trismus is an interesting condition. It's often really a presenting symptom than actually a defined condition. And it can be a symptom of many different disorders affecting many different tissues and holistically patient issues. On the clinic, we see a lot of it in dentistry but there's very little really written about it and really covering all aspects of the condition which I've attempted to do in this lecture. So, first of all, we'll look at definitions.
So, the definitions really stem back to, as many medical conditions do, to Greek terminology, and trismus is a term for grating or grinding. So right really from the outset, trismus was related to a hyper function of the masticatory muscles or, as we refer to it now, a bruxism or clenching habit. And true trismus is related to muscle function. But it has now sort of morphed in terminology that we define trismus as inadequate opening, inter-incisal opening of the mouth. The trismus can be persistent or spasmodic and, as I've underlined here, prolonged spasm of the jaw muscles is how many of our patients may present. But actually the jaw muscles may be fibrose rather than actually actively spasming and that's why it's important to try to and define true rather than false trismus. The normal range of our mouth opening is 40-60mm. Obviously, if you're a lead singer of a band like The Rolling Stones, the mouth opening will be considerably bigger than this, but this is the normal range. And trismus is usually defined as 20mm opening, 2cm opening or less, and that's usually defined simply by two small fingers.