Why do stubbed toes hurt so damned much?

Many's the time I've rolled around on the ground, grimacing and making animal keening noises and wondering why the hell humans evolved to experience such dramatic pain from toe-stubbing. Here is a plausible-sounding threefold answer from Chris Geiser, director of Marquette College's College of Health Sciences athletic training program. Part one is that we've just got a lot of nerves in our extremities because they're our interface to the world. But more interestingly:

Secondly and related to the first point, there is very little tissue in our toes to absorb this type of impact. Much like hitting our shin, there is no fatty tissue or muscle tissue overlying the bones in the toe to cushion the impact. Every bit of the kinetic energy created in moving our legs forward is absorbed by the skin and bone of the toe, resulting in very high compressive forces on the many nerve endings that reside there. Because the foot is at the end of the longest lever system in the body — the leg — feet tend to be moving much faster than any other part of the body when they come into contact with an unknown object. For these same reasons a pitcher can throw a baseball 90-plus miles per hour and a soccer player can strike the ball at roughly the same speed; the further away from the axis of rotation, in this case our hip, the faster the end of that segment is moving. Add the mass of our entire leg to this equation, and there's a large mass applying force to the toe at a great velocity in a small area not capable of adequately dissipating that impact. OUCH!
"The last part of this explanation comes from an evolutionary perspective. In the not so distant past, infections killed many people. Stubbing a toe can open wounds on the feet, which are constantly in contact with the bacteria-laden environment. It has been suggested that individuals who received lots of sensory information from their toes were less likely to strike them, creating an evolutionary advantage for people blessed with this type of sensory information. So there are many components to this amazingly painful question."

Big Question: Why does it hurt so much when I stub my toe? (via MeFi)

(Image: Toes, a Creative Commons Attribution (2.0) image from wonderferret's photostream)

I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.

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http://profiles.google.com/stephen.schenck Stephen Schenck

THANKS, evolution! Instead of mini toe-hooves, we get super-pain-sensitivity.
- fuzzyfuzzyfungus
  
  If you want the real thanks-for-nothing, it’s the fact that pain is ‘painful’ at all…
  
  Instead of a perfectly civilized peripheral status reporting protocol, we just get various flavors of pain, sometimes not even in response to actual stimuli.
  - Antinous / Moderator
    
    Pain is just a sensation. You can choose not to interpret it as negative. Now If you’ll pardon me, I’m due for my afternoon Vicodin.
    - http://twitter.com/trempls tré
      
      After that, you should probably hide out- Cuddy’s looking for you, something about clinic hours.
    - Wreckrob8
      
      Does that adversely affect your ability to experience pleasure as positive? Do you just end up indifferent?
      - Antinous / Moderator
        
        It shouldn’t, although if you were taking a classically yogic approach, I suppose that you would try to dissociate all emotions from experience.
    - niktemadur
      
      I can live with hunger for long periods of time with tolerable distress, so I understand what you’re talking about. I’m good at that and it annoys and preoccupies my wife (she’s right you know).
      
      Meanwhile, I have no fucking idea what you’re talking about :-P
  - http://www.jjsaul.com Jim Saul
    
    While you’re fixing the pain-feedback system, could you do something about allergies? Thanks.
    - http://twitter.com/trempls tré
      
      I’d also be interested in a patch for that whole “walk in, forget why you came, walk out, remember after two minutes” thing.
      - retepslluerb
        
        There are various patches for this, though.
  - Snig
    
    If it was, say, odd colors or a strange smell or something not very unpleasant, it wouldn’t be useful. You’d bang your toe, not care so much about it, then lose the foot later to gangrene. It has to be unpleasant for it to matter. False positives are a nuisance, but folks not caring about a sharp rock in the foot can be lethal.
    - The Rizz
      
      It should be unpleasant, yes – like some severe discomfort. But cripplingly bad pain, even just for a minute, can get you eaten by that predator you were fleeing from at high speed when your toe hit that rock…
      - Guido
        
        But that’s why adrenalin masks the pain, you don’t feel it as much when you are primed. Afterwards…
      - ocker3
        
        Thing is, the pain response should have been teaching you to pick up your feet while running for years before you ran into that apex predator.
    - fuzzyfuzzyfungus
      
      Based on the rather dreadful things that happen to people with Congenital Insensitivity to Pain, it does seem that humans aren’t really set up for more benign emergency signalling(though, consider the mechanism by which you move a limb to perform a task: even with your eyes closed, or focused elsewhere, you can ‘sense’ the location of the limb and guide it to target. If, instead of ‘hurting’, damage signals were incorporated directly as routing constraints, that might work).
      
      However, that’s because we are a ghastly pile of legacy-feedback-systems-upon-legacy-feedback-systems, which makes for a pretty mediocre user experience. Within the constraints of that mess, pain does cut through the clutter. Unfortunately, the constraints of that mess kind of suck, and are what preclude better solutions.
- SpaceBeers
  
  Stupid evolution. Not only did it rob us of having awesome tails but now this?!?
http://pulse.yahoo.com/_QWO37SNZEPIXVLTWY2R2MFK2KE YoDoe

“Thin tissue” doesn’t answer the why question. This does: ”individuals who received lots of sensory information from their toes were less likely to strike them, creating an evolutionary advantage for people blessed with this type of sensory information.” Obviously, we experience pain in the way we do because the alternatives are worse. Pain helps us stay alive. However, it’s worth thinking about the difference between fingers and toes. I don’t know if you agree, but I think that stubbing a toe is more painful than the analogous force to a finger, and experienced more often. Why might that be?

Well, we have a lot of brain space already allocated to fingers. They are closer to our eyes. We control them in much more precise ways. Arguably, we don’t need pain information to be encouraged to protect our fingers. But toes are attached far from our brains, waving around at the end of our biggest most active limbs, and not mapped into our brains with nearly the level of sensory detail that our fingers are. Because we have to walk, in fact, it is probably useful to be relatively insensitive to pain from our feet… unless we do something that is really bad for them… at which point our bodies would benefit from a really loud shout out.

So I hypothesize that toe pain is bigger and louder than finger pain, and perhaps for all sorts of good reasons. I could of course just be telling evolutionary “just so” stories. But as always, I find myself immensely persuasive.
- kromelizard
  
  They’re called “thumbscrews” not “toescrews” for a reason. You’re just underestimating the difference between the forces typically applied. You very, very rarely hit your hands as hard.
  - Tynam
    
    Subjectively, the immediate pain from the toe I stubbed five hours ago was worse than the pain from severely breaking my hand, five months ago.
    
    (Of course, the hand got worse over the next few hours, until I was nearly screaming, whereas the toe receded rapidly to ‘sore’. But the immediate sensation was every bit as bad.)
    
    Even at the time of the break, I found that comparison interesting.
    - kromelizard
      
      There might be something to the notion that there’s a difference in pain response. After all, your hands are within your field of view and well protected by the amount of attention a person typically pays to them. Your toes aren’t.
- Snig
  
  The hominid with an injured foreleg (hand) might still be able to gather, if not hunt. The hominid with a bum leg can’t keep up with the pack, can’t hunt or gather, and is slowest to avoid predators.
Comman Dax

I’m hoping the agony that results from my whipping the rubber jump rope into my toes over and over again while jumping rope barefoot at muay thai will eventually induce me to get better at it… the pain having the result of reducing clumsiness. So far all I have is a callus beginning to form on the top of my toes.
sam1148

Could someone please post another story for the weekend. I don’t want to see that toe all Sunday.
Paul Coleman

You know what’s worse that stubbing a toe. Stubbing a recently frostbitten toe.
- oasisob1
  
  Even worse: stubbing a recently liquid nitrogened toe.
http://www.spockosbrain.com spocko

Thanks for this. Now could you do a post why modern medicine can’t do anything about painful toenail fungus?
I have had my fungus leaden nail taken off but it grew back, took Lamasil and it didn’t work and the doctors will not prescribe it again because of potential liver problems. I have used topical treatment to no avail. I was told by my doctor that the new laser treatments will not work.

I asked, “what can I do about the pain?.” she replied,” take an aspirin and soak in Epsom salts.
- Antinous / Moderator
  
  Epsom salts work amazingly well for infections. Make the water as hot as you can stand it without actually damaging anything and soak for hours. Keep it hot.
- fuzzyfuzzyfungus
  
  Fungi are crafty.
  
  In (very rough) outline, if you want to treat an infection, you ideally need something that throws a wrench in the biochemistry of the pathogen without doing the same to the patient. Unlike bacteria, which are prokaryotic organisms (comparatively) unlike us in terms of life-critical chemical processes(nothing we know of on earth is too alien; but prokaryotes’ last common ancestor with us was quite some time ago), fungi are eukaryotic organisms much closer to humans.
  
  This narrows the list of possible targets to interfere with, since the pathogen and the patient share so many of them. So, antifungals tend to be both pretty nasty in terms of side effects and somewhat tepid in terms of efficacy compared to antibiotics. On the plus side, fungi are mostly rather half-hearted pathogens in humans, hanging around on the surface and making a nuisance of themselves, so this isn’t quite as perilous as it is when the drug-resistant bacteria show up…
- ocker3
  
  Things like Lamasil are more effective if used early. Once you’ve started going as serious as having things ripped off, medication may not work as well. I know it’s expensive, mine was subsidised by the Australian Gov because the fungus I was suffering from was on a hit list of problems that were really hard to treat (and more debilitating) the longer they affected someone.
Paul Renault

It’s not necessary to experience lasting intense pain when you smash your toes. Really!

A long time ago, this used to bother me: why is it that if I hit my fingertips hard onto a table top a few times, there’s only a short bit of pain. If there’s no broken bones, no hematoma, no real injury, the pain stops after just a few seconds. G’head, try it.

Yet, when I smashed my toes, I was incapacitated. Yet, like the fingers: no broken bones, no hematoma, no real injury – still the pain peristed and with great intensity.

So I promised myself that the next time I smashed my toes, I’d acknowledge the pain but remind myself (assuming no real injury) that It hurts in your head, not in your feet.

A few days later, it happened, I smashed my toes. I cursed, then I paused for a second and then I forced myself to walk normally and to not favour that foot. The pain stopped almost instantly.

Years later, my sister stepped on a nail – which only pierced the skin. She was in pain. Ever so considerate, I looked at her and said “It hurts in here (tapping my temple), not there (pointing at my foot). Force yourself to walk normally, the pain will go away.”

She didn’t limp afterwards and she’s still talking to me…

An appropriate NSFW Chopper Reid video:
https://www.youtube.com/watch?v=1EY7lYRneHc
- Tynam
  
  Now that’s a really interesting bit of pain management. Thanks for the story. (Of course, all pain is in your head, although there are many cases where you have unavoidable reasons to feel it…)
- Antinous / Moderator
  
  When I stub my toe, I step on it firmly with the heel of my other foot. The pain usually subsides after a few seconds. Presumably I’m creating some sort of signal conflict.
  - Paul Renault
    
    Or maybe you’re overloading the neurons and exhausting their resources (ions?). It’s a technique that some dentists use to numb the soft palate, by pressing on it with a finger or thumb, to reduce the pain of inserting a hypodermic.
  - http://www.jjsaul.com Jim Saul
    
    Plenty of science to back that up… a friend worked on this study and she kindly sent one of the gizmos for my nephew, who had to get an insane number of injections during a health crisis:
    
    PDF http://digitalarchive.gsu.edu/cgi/viewcontent.cgi?article=1037&context=psych_theses
    - AllyPally
      
      But the conclusion of the report is the thing doesn’t work. Placebo effect only.
      - Paul Renault
        
        So Chopper Reid’s advice still stands! Yay!
      - http://www.jjsaul.com Jim Saul
        
        Shhhhh!
        
        The first rule of Placebo club…
        
        That explains why my nephew said just pinching his thigh higher up than the shot worked better.
- oasisob1
  
  There is no spoon. I’m with Antinous: put pressure on the ouchy spot, pain goes away, confused, apparently.
http://pulse.yahoo.com/_EP2SEPYCCZMRYIAERCXDLFIRWM AnthonyI

One of the most painful things that I’ve experienced was having an ingrown toenail on my big toe removed surgically by a doc. People roll their eyes at me when I tell them that thinking I am just being a baby. I think I have a higher than average threshold of pain too. But it was horrible, my whole leg throbbed nonstop for several days, the Tylenol 3s didn’t do anything for me.
- Paul Renault
  
  Y’see there, there actually was some damage (the surgery). So it’s normal/reasonable to experience pain.
- http://codeflow.org/ Florian Bösch
  
  Had that, been there, it sounds really silly but damn it hurts, and nothing makes it go away until the friendly surgeon scrapes away a bit of skin, collage, root and bone and makes stuff stop growing in that direction.
- blueelm
  
  I’ve always been curious about that. Don’t you feel the ingrown nail at first? Or does it just always grow that way? Whenever I’ve gotten one I’ve just cut it out as soon as I notice it, but I’ve never had one that was really bad or anything. So just a mild cut, prying it out and putting something between the pulled-out nail and the toe flesh was enough. Mmmm… sexy talk.
- Antinous / Moderator
  
  I have mildly ingrown toenails. I have a go at them about once a month when they start to get twingey and occasionally there’s a bit of soreness for a day or two. My mother’s big toenails formed 270° of a circle! Eventually she had a radical toenailectomy.
http://codeflow.org/ Florian Bösch

So we evolved sensitive toes because that’s how we could most effectively hurt ourselves? Brilliant…
- http://profile.yahoo.com/65CSAR3QATRNKJW4NYNB2BESZE JohnQPublic
  
  Evolution guided us to protect our feet from walking into harm by sending pain signals to make us stop, yet people still pay money to attend Tony Robbins workshops to walk on hot coals and get 3rd degree burns on their feet…
blueelm

I started to say “but hitting your toe doesn’t hurt that bad” and then I remembered the years of dancing on them and wearing shoes that dulled the sense of pain by causing constant pain.
http://twitter.com/randywalters Randy Walters

I remember running down a home hallway when I was about 12, catching my little toe on a piece of moulding and curling up in a ball of utter agony. The memory has never left me.
Mazoola

Then toss gout into the mix, and all the arguments for the importance of toe sensitivity and tricks to interrupt the signalling of pain go right out the window.
http://web.ncf.ca/shawnhcorey/ Shawn H Corey

And you need a scientist to write a paper about this? The reason why it’s so painful is to make you avoid from doing it again. It’s that simple. People tend to avoid painful situations. Receiving a lot of pain when you stub your toe means you’ll watch where you’re putting your feet. Being careful means less chance of injury and infection.
- RedShirt77
  
  The question is just as much about, why our feet are so injury prone as why injury hurts so much.
  
  Injuries mean no walking, but avoiding injuries makes it hard to Hunt, or avoid being prey
- Snig
  
  There’s no paper, and no scientist (at least no evolutionary biologist). It’s just someone asked a PT professor about it and put it on the web.
RedShirt77

I think this guy is missing the point a bit.

Real answer is that evolution is a work in progress and our feet are sort of filling some needs and failing tragically at others in the same way our back is.

Our ancestors needed hand like feet to hang and run in trees. So the lacked the frost bite resistant hooves or paws that almost all land animals use. Those more evolved for land locomotion are harder to injure, less prone to frost bite and temperature discomfort.

On the other hand all the nerve endings, articulating toes, and flappy long feet make our feet better dor bipedal standing, swimming, and fetish porn.
Atvaark

Why does looking at a picture hurt so much?
- Wreckrob8
  
  So you can enjoy it all the more when you stop.
  Seriously, I can’t help thinking that we need both physical and emotional pain and pleasure messages to motivate us creatively (even if the messages are created by different physiological processes/systems).
  No pain, no empathy?
BombBlastLightingWaltz

“Many’s the time I’ve rolled around on the ground, grimacing and making animal keening noises…”

Also known as Involuntary Tourettes Syndrome (ITS)
tobergill

As a Vibram Five Fingers user, I am evolutionarily confused. I can attest to the severe pain of regular toe stubbing while running on uneven surfaces, but they banished my knee pain completely. What to do…..
Blanche Beecham

I’ve been tricked into both pregnancy and toe surgery. Of the two, I prefer giving birth naturally, without painkillers to having the entire toenail removed (with painkilers) for an ingrown situation.

This is nature’s way of endorsing shoes and condoms.
Greg C.

It’s truly a devastating experience. You’re walking about the house minding your own business, without any shoes on your feet, focusing on what you need to get done, then the inevitable happens. You step too close to a piece of furniture … and {{{{WHAM!!}}}}, you stump your toe. The pain spreads like an explosion in your foot as if you stepped on a landmine or something.

The next thing you know, you’re cursing that peice of furniture and grabbing your foot while you’re on the floor rolling around in pain, or hopping around like a wounded kangaroo on one foot.

It has happened to all of us.

I think stubbing ones toe hurts more than if it was run over by a bus. And what’s even worse, is that the pain gets more intense as time goes on. OUCH!!!!!!!
- RedShirt77
  
  Worst part is it takes weeks to heal if you bruise a joint or even break a toe.
  
  Bur is it worse than stubbing your face?
  http://youtu.be/u33ivAO_Zyk