By Erika Owen
March 20, 2017
Credit: Jeremy Yap

We've all got them — the thin lines that run across your palm.

While some might think they were put there for a fortune teller to unveil your future, that's not necessarily the truth. Business Insider dug into the scientific reason why we've all got these lines, and discovered a few fun things along the way.

It may seem like common sense, but the lines are there to make sure your skin doesn't bunch up when you open and close your hands. Just imagine: Forming a fist would become the most uncomfortable thing a human could do if you had a fistful of bunched-up skin to deal with.

This little body trick is all in the name of dexterity, making it easier for humans to grip things.

Most people are born with three major creases on their palms. Each line, though, is a different thickness, prominence, and length. This is determined by a person's genes. In rare cases, someone might have only one dominant crease on their palm — this happens for about one out of every 30 people. And it has a name: single palmar crease. This irregularity may also be a sign of abnormal growth, and often is an indicator of Fetal Alcohol Syndrome, Down Syndrome, Turner Syndrome, Rubella Syndrome, and Aarskog Syndrome.

Want to know more about the lines on your hands? Check out the video on Business Insider.