An activator incident: can a light tap injure the neck?

Chiropractic “activators” are tiny spring-loaded “hammers” that “tap” the spine to “adjust” it. They can definitely waste your time and money, but … can they hurt you? Just a little tap? A reader asked:

A chiropractor hit my C2 vertebra with an activator, and I’ve been dizzy/nauseated for 3 months since then. Could a gentle tap on the cervical spine cause this?

Maybe. It would be a bit of a freak accident, but freak accidents happen. I think it’s possible — and worth thinking about how it might work.

Not actually a chiropractic “activator” … but a bizarre AI-generated depiction of one. The real thing is much tamer, with a rubber business end. This image is typical AI slop, obviously a “creative” mashup of several small tools. I have tried using AI for a lot of simple images, and it just sucks at realistic depictions of specific objects. This is the best I could get after extensive experimental prompting to make the image more accurate. 🙄 The result is abstractly amusing and fascinating — I love how tool-esque it is, without actually resembling any specific tool — but it’s completely useless. If you want to know what a real chiropractic activator looks like, search for it!

We know that spinal movement can go badly. Anything from hair-washing (seriously) to strong therapeutic manipulations can have serious consequences for some spinal vulnerabilities, such as tearing arteries or poking the brainstem. We can extrapolate from those examples, and it is plausible in principle that even minor passive manipulation of the upper cervical spine could cause some trouble.

The difference between passive neck manipulation and active neck movement is the key here:

• Passive cervical manipulation is anything that is done to your neck — movement of tissues that you didn’t initiate.

• Active movements, of course, are the movements you control — with all the details unconsciously micromanaged by your brain on your behalf, in service of your high-level commands. “Look over there” involves an army of details. You don’t have to think about what to do with your rectus capitis posterior minor muscle, thankfully.

When your neck movements are up to you, your body makes accurate, rapid, and even aggressive compensatory adjustments to protect you from a vulnerability, such as instability or a position that irritates nerve tissue. Some people probably go their whole lives “working around” such vulnerabilities, never even knowing they exist.

Such stealthy vulnerabilities could still cause symptoms occasionally, because perfect protection always possible for this system. Accidents happen! But mostly … it just works.™

But deliberate and novel passive manipulation might surprise the brain, imposing movement on a vulnerable spine that it never would have permitted in active movement.

A chiropractic “activator” could conceivably be an example of this in principle, but it would be surprising if it could do much damage in practice — it’s probably too gentle. Skeptics and critics justifiably make fun of how clinically trivial they seem, because they do so little physically that it’s highly implausible that they can be therapeutic. But that means it is equally implausible that they can do harm.

And yet not impossible. If you’re close to the edge of a cliff, it doesn’t take a big push to slip over it. It would take a perfect storm, but that active/passive distinction is important, and I can imagine it combining poorly with a particularly delicate vulnerability, and more aggressive use of the activator.

Or it was all an illusion! Maybe the activator wasn’t the active ingredient in my reader’s misfortune. The true culprit could be passive neck movement before and after the activator usage! 🤷🏻‍♂️ That’s probably more likely. But I do think activators have at least a little bit of potential to do harm — beyond wasting your time and money, that is.

See also: Chiropractic with a hammer. Not all spinal tapping is gentle!

P.S. Why didn’t I use a real activator picture?

I could have! I have used product images in my posts from time to time because — although technically violating someone’s copyright — the copyright owner is rather unlikely to be unhappy about it. Indeed, if you link to the product, they may even see it as a favour.

But it’s a grey area, and certain kinds of products and copyright holders are best avoided … and/or I don’t want to “endorse” them. Chiropractors are notoriously thin-skinned and litigious as a group — which I have learned the hard way — and so I chose not to risk even a tiny provocation over an image that isn’t terribly important to the post. But I still wanted some kind of image!