Having a dark line on your fingernails or toenails is called melanonychia. The lines are brown or black and usually look like a stripe that begins at the bottom of your nail bed and continues to the ...

Melanonychia is the term for dark pigmentation of the nails. The discoloration in the nails may be black or brown. Melanonychia can be a natural occurrence in people with dark skin, but it can also ...

Q: My friend has a vertical line-like discoloration on his nail. What is this from? A: Nails are made up of the same protein as skin (keratin), so in a way they can be thought of as hard translucent ...

A black line on your nail (medically known as melanonychia) causes a streak of dark pigmentation that runs along the nail bed. It can be a normal color variation, especially in people with darker skin ...