"Nail growth is determined to a large extent by blood supply. So, all other factors being equal, the nails that get the greatest supply of nutrients from the blood will grow the fastest? Interestingly, increased blood flow can be triggered by injury. (The body’s natural reaction is to send more blood and nutrients to damaged areas. Because your hands are constantly interacting with the environment your finger nails experience a greater degree of tapping and bumping than your toenails do (since they’re tucked away in your socks and shoes.) It’s thought that this constant barrage of “micro-trauma” is enough to trigger the body’s defense mechanism. So, more stress on the nail results in more blood flow which leads to more growth. Clever, huh?"
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