What's wrong with vertical lines on the nails

Many people inadvertently will find their fingernails on the growth of obvious vertical lines, the nail surface appears one or several raised vertical lines, often reflecting a person's physical fitne

What's wrong with the black vertical lines on the nails?

"As an accessory to the skin, the nails occupy a negligible proportion of the human body, but we should not underestimate the appearance of the nails. A beautiful nail not only adds a lot of charm to