American scientists from Binghamton University have revealed why the skin on the fingers wrinkles after prolonged contact with water. It turned out that the wrinkle patterns in each person are formed according to the same scheme associated with the work of blood vessels. The study is published in the scientific journal Journal of the Mechanical Behavior of Biomedical Materials (JMBBM).

It was previously thought that wrinkles appeared because the skin absorbs water and swells.

In the new study, the team conducted an experiment in which participants immersed their fingers in the liquid for 30 minutes. After 24 hours, the procedure was repeated. Comparison of the pictures showed that wrinkle patterns (loops and ridges) remained identical in both cases.

 “The blood vessels in the fingers do not change their location, so wrinkles form in the same 'pattern',” the scientists explained.

Interestingly, in people with damage to the median nerve (which is responsible for sensitivity of the fingers) wrinkles do not appear at all. This was confirmed by a test involving a student who had such damage. 

The discovery may help in identifying fingerprints, even if the body has been in water for a long time. 

Scientists plan to continue research to see if this mechanism can be used for other tasks - for example, in medicine or biometric technologies.