Why Is A Paper Cut So Extremely Painful?

You know when you get a paper cut and you say, why does this hurt so much more than anything else.
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You know the dreaded moment when you feel that familiar but nevertheless shocking surge of pain on your finger. You were just trying to mail a letter to your Great-Aunt Celia to thank her for the hand-knitted mittens she sent you for Christmas, and then it happens.

Your fingertip is searing in pain; it feels like a knife just sliced through your top few layers of skin. And that pain is just a simple paper cut.

It’s such a small paper cut and barely even draws any blood, so why does it hurt so badly?

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Paper cut on a finger, by Laurence Facun, licensed under CC BY 2.0 via Wikimedia Commons

The dreadful paper cut is just a fun little thing we humans unintentionally do to ourselves to keep us on our toes. You thought you had good hand-eye coordination? Well, think again. One reason why these annoying little cuts hurt so badly is because they usually happen on our most sensitive areas like the fingertip, lip, or tongue.

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The fingertip consists of layers of skin that make paper cuts hurt more and bleed less. The outermost layer, which is known as the epidermis, is very thin like a sheet of paper. Under that layer is the dermis. This is where all the nerve endings are.

The dermis is a bit thicker, about 5 or 6 millimeters, and a paper can easily cut well into the dermis layer, lighting up all those nerve endings and setting your fingertip on fire, not literally, of course.

But the reason it doesn’t bleed very much is that the cut doesn’t go deep enough to hit the blood vessels. That’s kind of good so you don’t make a bloody mess all over your paper, but somehow it actually makes it worse since blood is full of wound-healing chemicals that activate cells to get the blood to clot and protect the wound.

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Unfortunately, a paper cut doesn’t get the benefits of blood, so this relatively superficial cut may not heal as quickly.

The edge of a paper is not sharp

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Another reason a paper cut hurts so much is that even though a piece of paper is flimsy and doesn’t look anything like a blade, the edge of a piece of paper can be razor-sharp. You can’t really see it with your naked eye, but the edge of a piece of paper resembles something more like a saw with a serrated edge and does a lot of microscopic damage to your fingertip when it cuts it.

Have you ever tried to cut through something with a dull knife? The knife pulls and tears rather than easily slicing through it. That’s what paper does to your fingertip when you get a paper cut.

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Risks of paper cuts

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Now if you get cut by a piece of mail or a well-worn library book, then there’s also the chance of bacteria being spread into your paper cut, which can lead to infection. You definitely don’t want that to happen, so make sure you always clean your paper cut with soap and water and cover it with a bandage right away to prevent infection and keep it from reopening.

Having more nerve endings in your fingertips, then anywhere on your body, is the reason why it hurts so bad!

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That’s right, your fingers are jam-packed with neurons. Some of these neurons are called nociceptors. These are sensory receptors to detect potential harm.  Nociceptors make it possible for the nerve networks on your fingertips, lips, and tongue to precisely identify feelings of pressure, heat, cold, and injury.

Your brain even has a specialized area to receive incoming signals from these parts in high-definition. The heightened sensing ability of your fingers, lips, and tongue makes injuries to these parts of your body all the more painful.

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There’s also a psychological element to the pain of a paper cut. Considering that these highly sensitive areas are parts of the body that you use all of the time, it’s very near impossible to forget about your injury.

Not bleeding on the area of paper cuts, leave chances of getting new injuries

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Another problem is the fact that a paper cut is a shallow wound that bleeds very little. This means the damaged nerve endings are left exposed near the surface of your skin, making that area feel especially vulnerable to new injuries.

In addition, a fresh cut on your finger, lip, or tongue will tend to reopen throughout the day, causing you to relive the sting over and over again. If you were to get a paper cut on your forearm or your back, the likelihood is that the sensation wouldn’t feel as sharp and painful since your nerve endings are a bit more spread out on those parts of your body.

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If you’d like to try an interesting experiment to test this out, try taking a paper clip and unbending it so that the two points match up next to each other. Press the two points into your fingertip, and your brain will sense that there are two different points of pressure.

But if you take that same paper clip and press it into your forearm or your back, your brain doesn’t register that there are two separate points of pressure. You’ll just feel it as pressure in one area. Pretty cool, huh?

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