What's the name of a long vertical line under the little finger?

Little finger stripes. A long vertical line under the little finger, usually called the horizontal line of the little finger, is also called the sailor line or the healthy line. It is one of the lines of the human palm, in the middle of the palm, starting from the little finger side and extending towards the wrist. The little finger stripe is formed due to the physiological structure and growth mode of skin tissue. Everyone's palm print is unique, just like fingerprints, so it is used as a way of identification.