EXCERPT This article is a condensed excerpt from three of PainScience.com’s advanced tutorials about low back pain tutorial, neck pain, and myofascial trigger points. It’s also discussed in a more basic sciatica tutorial. But it’s also interesting enough to be worthy of its very own page.
I recently came across this full-page advertisement in National Geographic magazine:
“Do you feel burning pain in your feet?” the ad asks. “Or uncomfortable tingling, numbness, stabbing, or shooting sensations? If so, you may have nerve pain.”
Yes, you might. But it’s not bloody likely! The clinical reality is that neuropathy is a lot less common than nearly all patients and most doctors believe.
Nerves make people nervous! So to speak. The whole idea of nerves gets people anxious. Could it be a nerve? people ask. Is this a nerve problem? What if it’s a nerve? Is something pinching my nerve? Something must be pinching a nerve.
The kind of advertisement with the stinging ants you see above greatly aggravates our society’s general anxiety about nerves. Pfizer and other pharmaceutical companies spend about a gazillion dollars on marketing that can create more worry about nerve pain in a year than I can counteract in an entire lifetime of low-budget public education! Bummer.
It’s amazingly difficult to actually pinch most nerves, or nerve roots (as they exit the spine). In general, nerves have extremely generous “wiggle room.” For instance, in the lumbar spine, the holes between the vertebrae that the nerve roots pass through can be more than a couple centimetres at their widest, while the nerve roots themselves are only about 3-4mm thick.1 If you stretch or compress the spine, the holes do change size a little — as much as 70–130% in the looser neck joints,2 a little less in the low back.3 But even at their smallest, there’s still plenty of room.
There’s so much space for nerve roots that even dislocations routinely fail to cause impingement.4 Once again, I invoke the example of a patient with a severe lumbar dislocation … and no symptoms at all, not even symptoms of pinched nerve roots. Her nerves seemed to be fine, even in an anatomical situation most people would assume to be extremely dangerous.
Yesterday I was working with a young woman who had “sciatica.” Allegedly, her sciatic nerve was pinched by her piriformis muscle — a reasonably common scenario — and sending hot zaps of pain down her leg. She came to me with this diagnosis already in place. She also had some tingling in her feet. The description of her symptoms did, indeed, sound a lot like a nerve impingement problem. On the face of it, it did seem likely that her sciatic nerve was being pinched.
However, a couple things didn’t add up. For instance, she had no numbness at all — no dead patches of skin, which are highly characteristic of true nerve impingement. Instead, she had a lot of “dead heaviness” in the leg, a different kind of numb feeling that is much more closely associated with muscle knots than nerve pinches — and a lot more common.
I quizzed her carefully about the quality of her pain. She assured me it was “zappy” and “electrical” … just as you would expect of nerve pain. Yet something didn’t seem quite right. I couldn’t shake the impression that she was interpreting an intense non-neurological pain as a “zappy” pain simply due to her strong belief that she had a nerve problem. When you think a pain is nervy, you’re going to interpret, feel and describe it in nervy terms.
So I did some experimenting, and clinched the case:
This young woman’s “nerve” pain could be perfectly reproduced by prodding muscle tissue that was nowhere close to the sciatic nerve. Pressing on the side of her hip, on the gluteus medius muscle, several centimetres away from the sciatic nerve, she reported the same “electrical” pain flowing down her leg. It even stimulated the weird, tingling sensations in her foot.
This largely eliminates a diagnosis of sciatic nerve impingement.
In spite of spending most of my career trying to explain to people that this sort of thing is common, I was surprised myself — fooled, really. Muscle knots are always fooling patients and professionals alike. Vastly more common than nerve problems, and often more painful, they nevertheless get upstaged and misdiagnosed by another phenomenon.
Do you feel burning pain in your feet? Or uncomfortable tingling, numbness, stabbing, or shooting sensations? If so, you are more likely to have “muscle knots” than nerve pain.
For more information about muscle knots, see Trigger Points & Myofascial Pain Syndrome For a detailed discussion of nerve pain overdiagnosis in the context of neck pain, see Save Yourself from Neck Pain! Low back pain? I’ve written a book about that, too: Save Yourself from Low Back Pain!
I am a science writer, former massage therapist, and I was the assistant editor at ScienceBasedMedicine.org for several years. I have had my share of injuries and pain challenges as a runner and ultimate player. My wife and I live in downtown Vancouver, Canada. See my full bio and qualifications, or my blog, Writerly. You might run into me on Facebook or Twitter.
Researchers dislocated neck joints in corpses to measure the effect on the size of the intervertebral foramina. (Interesting chore!) Dislocation made the spaces quite a bit larger, indicating that any nerve root pain associated with these injuries “is probably due to distraction rather than due to direct nerve root compression.”BACK TO TEXT