It is not just medical authors who use metaphors. It is not just in medical writing that we find them. We—doctors and patients—use them every day. Can you describe the pain? It’s like a knife; it’s as if someone was grinding their fist into my breastbone; it was just like a heavy weight on my chest; it felt like passing a large watermelon; it was a burning sensation. We can to an extent quantify pain by saying how long we have had it, and whether it is constant or variable. We can say how bad it is, perhaps not precisely or reproducibly, but its character is definable only by comparison with something we already know. As doctors, we can then define pain by its cause—ischaemic pain, colicky pain, neuralgic pain—but that will never be a patient’s first description. Actually, that is probably no longer true, if they have already visited Dr Google.

We also use pain metaphorically: we describe an annoying person as “a pain”. For reasons unknown, if we become more specific we talk only of “a pain in the neck” or, more in the United States, “a pain in the ass”. What is so special about the neck? Neck pain is very common, and is often chronic, but so is backache; so are headaches. We might describe a difficult problem as “a real headache”, but I’ve never heard a person described so. Why do you never hear someone called “a proper lumbago”, or “a real sciatica”?

The OED first records the metaphorical use of pain in 1908—is there really no earlier use? Surely Shakespeare must have used it somewhere. PG Wodehouse is credited with the first “pain in the neck” in 1924. “Pain in the ass” (rather quaintly, the heading in the OED lists this as “pain in the arse”) is first recorded in 1972. There aren’t entries for the alternatives “pain in the bum” (British) and “pain in the butt” (US).

I’m intrigued to know where exactly in the posterior regions the pain is felt. (“Pain in the posterior” is another variant.) Is it the pain of a trapped haemorrhoid? Of proctalgia fugax? Or is it felt more in the buttocks? Is it a greater or lesser nuisance than a pain in the neck, or are the two pains equivalent? Can you measure the pains on a ten point scale, or is none-mild-moderate-severe good enough? Can you use parametrically based statistics?

And then there is heartache, which originally meant what we now mean by heartburn, but since Shakespeare’s time has come to mean the anguish of disappointed hope: the OED’s first attribution is to the most famous soliloquy in English literature, “To be, or not to be”:

…To die, to sleep—

No more—and by a sleep to say we end

The heartache, and the thousand natural shocks

That flesh is heir to.                                                              [Hamlet Act 3, sc i]

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

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.