Paper cut

A paper cut occurs when a piece of paper or other thin, sharp material slices a person's skin, most often on the upper part of the index finger. Notably, "paper" cuts can also be caused by thin, stiff, and abrasive materials other than paper. Paper cuts can be highly painful, even though they may bleed very little, if at all.

Although a loose sheet of paper is usually too soft to cut the skin, it can be very thin (sometimes as thin as a razor's edge), and can thus exert enough pressure to cause a cut. Paper cuts are most often caused by paper sheets that are strongly fastened together (such as a brand new sheet of paper out of a ream), because a single sheet might be dislocated from the rest. In this case, all the other sheets are holding this dislocated sheet in position, making it stiff enough to act as a razor.

Paper cuts can be very painful, as they can stimulate a large number of skin surface nociceptors (pain receptors) in a very small area of the skin. Because the cut typically does not bleed much, the pain receptors are left open to the air, causing continued pain. This can be exacerbated by irritation caused by the fibers in the paper itself, which may be coated in chemicals such as bleach. Additionally, most paper cuts occur in the fingers, which have a greater concentration of sensory receptors than the rest of the body.