What makes paper cut wounds so painful?

Many, while immersed in the reading of an interesting book or an interesting novel, experience great pain when turning the page very quickly, causing the paper to sore one of the fingertips.

Although this wound may be very small, it causes a feeling of sharp and intense pain, like more serious injuries, striking in their effect.

Why are paper cuts so painful?

It’s not the size of the wounds themselves, but rather the areas of the body where we often see paper cuts.

The reason paper cuts are so painful is because our hands are incredibly sensitive to pain and the edges of the paper are surprisingly jagged.

Human hands and fingers carry a high concentration of nerve cells called pain receptors that respond to signals from damaged cells, according to BrainFacts.org.

The pieces of paper are primarily activated by pain “mechanoreceptors” that sense cell damage caused by pressure, cuts and punctures, as opposed to damage caused by extreme temperatures, for example.

A paper cut can also activate pain receptors that are sensitive to chemical stimuli, such as bleach used to lighten paper, and these neurons can cause an itchy sensation around the paper cut.

Activated pain receptors emit a wave of electrical signals that travel through bundles of nerve fibers to the spinal cord. Nerve cells in the spinal cord then relay these signals to the brain.

Finally, the signals reach an area of ​​the cerebral cortex responsible for sensations of touch, temperature and pain, known as the somatosensory cortex, according to StatPearls.

The somatosensory cortex curves over the surface of the brain like a headband, with different areas of the headband representing different parts of the body.

Hands and fingers are full of cells sensitive to touch and pain, so the headband areas dedicated to them are huge compared to less sensitive parts of the body like the torso.

The mouth and tongue occupy an equally large area of ​​the headband, which helps explain why cutting the tongue while licking a mailing envelope can be so painful.

But it’s not just the anatomy that makes paper cuts oddly painful. Even the paper itself increases the agony. Although it appears smooth to the naked eye, the dried wood fibers pressed into the paper make the edges of the material very jagged at a microscopic level. This rough texture causes more extensive cell damage than clean, straight edges.

However, the jagged edge of the paper usually cuts only the top two layers of the skin—the epidermis and dermis—and thus causes little or no bleeding. This reduces the chance of clotted blood clogging the wound. As a result, damaged nerve fibers remain open to the elements for a long period of time and release pain signals when touched.

To treat a paper wound, wash it with soap and water, apply an antibiotic ointment to prevent infection, and cover it with a bandage, according to the Ohio State University Wexner Medical Center.

Most paper wounds heal within two to three days, but if the condition of the wound hasn’t improved in that time, it’s best to see a doctor to check for signs of infection.

Source: Living Science