How do fingernails grow?

Fingernails grow from the root of the nail, pushing old cells out which flatten and harden, as new cells take their place. The flattened and hardened nail then slides along the nail bed, which is fed with minuscule blood vessels.

The nail root is not visible, since it is located under the cuticle of the nail. Nails are made of keratin, which is also used to make hair and the top layer of human skin. Keratin is what causes nails to harden, protecting the fingers and toes. Nails grow at a rate of approximately 1/10th of an inch monthly, which is why it generally takes a full, 3-6 months for a nail to grow after a surgery or accident.