What do ridges on the fingernails indicate?

my aunt who is a docter has always told me that this is an indication of low calsium levels.

This is normal

Nothing you need to worry about

I don't know, but i have them, too, and they progressively worsen, it seems.  doctor has looked and doesn't know (imagine that?!).  with mine, the ridges are deep and horizontal.  the cuticles begin the process it seems with disintegrating, so to speak little by little, to where there is no more cuticle at the "moon" part of the nailbed.  then, the ridges begin as small dents in the middle of the nail, and progressively more dents become obvious and they deepen.    it don't look good, if ya know what i mean, but the main thing is what does it mean???  anybody else ever have it?

this website at mayo talks about verticle ridges, but what about horizontal ridges?

Were your ridges horizontal?  Did you also have missing cuticles on the nails where there were ridges?  Thanks for your input...  one last question, was there any eczema involved on your fingers, hands, elsewhere?