How do nails know which direction to grow?

They know to grow forward, not to the sides. How do they know?How do nails know which direction to grow?
Nails are the remains of cells undergoing programed cell death. they are derivatives of dead protein as KERATIN. Note that they are all present at the extremities of the body. You might have not noticed the ';growth'; of nails. You think that nails grow. They never do so. They are actually outpushings from the metabolic esp. catabolic wastage of the body. The dead cells are pushed thro' the skin. Their protein wastes are nails and hair. Now to direction !





They actually proceed toward gravity.You can notice it, when you allow them to grow upto their ';freedom';.How do nails know which direction to grow?
Nails do not ';grow';. They are not alive. They are not cells and they do not contain DNA. Nails (and hair) are excreted by living tissue.
They don't. Sometimes nails grow upwards toward teh face. But then they grow so long that they stab the person in the face. So they die. That's why you don't see anyone with nails growing upwards.
i guess they're just smart!
as anything grows...away from the root