What's wrong when your fingernails have lines?

Recently all my fingernails have developed dark horizontal lines in the middle of the nail. It follows the shape of the base of my nail. Any idea whats wrong?

I bit my nails for 45 years (I'm 48 years old). I stopped a few months ago and am enjoying having nails! However I have noticed that the "white part" of the nail. You know the part that extends beyond the finger, has lines of transparency....

So I have black lines on my fingernails and I just absolutely hate it. I have to wear nail varnish everytime I go out because I don't want anyone to see them. At home I don't because my family already know. It has lowered my confidence a bit due to the...

i've seen thai dances.... what do you call that dance with long conspicious fingernails flattering... by the way what is up with those golden extensive fingernails?... the goddess is asking for thy input! vegetables be with you!

All my fingernails have black lines in them, any idea what that is? Can it be serious?

I have searched all over the internet and cannot find any answers as to why my fingernails have straight black lines running lenghtwise. Also part of my cuticle is now looking black...My doctor says it's not a fungus but doesn't know exactly what it...

Hi, I noticed that I have 2 vertical lines ( 3 mm wide ) in my two fingernails. Initially I thought it was just something small and would go away when my nails grow - However ...show more

when i go take a picture i see vertical lines on the lcd screen. I point and shoot and take the picture. well when the picture appears on the screen it is grey and black(looks like a negative) at first with little lines in it and then the screen will...