Why do some people's nails grow curved-up,others curved-down and some don't even grow?

That's just how they are lol, like how you might get freckles or the shape of your eyebrows. Or it could be another problem.





http://www.salonweb.com/nail2.htm :


Will artificial nails keep my nails from growing crooked?


If your nails have always grown a certain way, they will continue to grow that way until you die or something changes your nail matrix (the ';brain'; of the nail). Nail enhancements can only ';cover'; your natural nail appearance, not change it.





http://www.stopbitingnails.com/nailinfo.鈥?/a> :


4. Dark nails and/or thin, flat, spoon shaped nails are a sign of vitamin


B12 deficiency or anemia. Nails can also turn gray or dark if the hands are


placed in chemicals such as cleaning supplies (most often bleach) or a


substance to which one is allergic.


6. Downward-curved nail ends may denote heart, liver, or respiratory


problems.


7. Flat nails can denote Raynaud芒鈧劉s disease.


12. Nails that broaden toward the tip and curve downward are a sign of lung


damage, such as from emphysema or exposure to asbestos.