Metaphors have a life and get tired, but dead metaphors are not just ones that have become very tired indeed. Dead metaphors have lost their original imagery, and have become absorbed into everyday language. For many people, some metaphors were never live. Those not familiar with baseball probably infer from its context that “step up to the plate” means get on with it, without realising that the plate is the physical part of a baseball field where the batsman faces the pitcher. For those who are familiar with baseball, “step up to the plate” will pass from the pen of the writer to the mind of the reader without a thought being necessary on the part of either (which was how clichés were defined by—I think—Philip Howard, though it might have been Bill Bryson). The individual words step-up-to-the-plate are not really heard; they are interpreted simply as start.

Linguists argue about the idea of a dead metaphor, and the argument doesn’t matter to us. What matters is trying to write simply, clearly and succinctly, occasionally enlivening our writing—and more commonly our speech—with appropriate metaphors. Mindless use of metaphors risks restoring the imagery, which is disturbing, and sometimes comical. “The health service has reached breaking point” is metaphorical and clichéd, but “The fracture clinic has reached breaking point” is silly. “Cutting edge” is metaphor for the most advanced—but what to make of a Japanese medical institute that has a research group for “cutting edge research?” “To bend over backwards” is a way of saying trying their utmost, but patients bend over backwards to attend their physiotherapy brings to mind just that. As does “managing to keep their heads above water” when describing an association of head teachers, or the Sports Council’s procedures for collecting urine samples being “made watertight.”

I found an article that contained both “bend over backwards” and “grasp the nettle.” Put those together—bend over backwards to grasp the nettle—and you have a mixed metaphor. Dead metaphors and mixed metaphors, used consciously, can sometimes work well; but they, and in fact all metaphors, risk upsetting the (often too) formal nature of medical writing. I was co-author on an article about the doses of drugs used for the induction of general anaesthesia. We titled it, “Two inches from the big syringe”—a title that would be understood by all anaesthetists, who we thought would infer (as we wished them to) that anaesthetists sometimes didn’t think very hard about dosage. One of the referees commented that the title was not suitable for a serious medical journal, which goes some way to explain why the medical journals make such tedious reading.

Competing interests: I have read and understood BMJ policy on declaration of interests and declare that my only competing interest is my co-authorship of a book about medical English.

Neville Goodman is a retired consultant anaesthetist and a writer, and co-author of a book on medical English.