Quiz: Fun Facts About Your Hands

Fingernails grow about twice as fast as toenails, at 3.47 millimeters per month compared with 1.62 millimeters per month.

If you position your hands correctly on the keyboard, your left hand will do 56% of the work.

Broken pinkies make up about one-third of all hand fractures in adults. Why? The pinky isn't as protected hanging out there on the end, and the bone is about the width of a pencil.   

Even though most of your body’s moving parts have muscles, your fingers don't. They're moved by muscles in your wrist, palm, and forearm that are attached to tendons, or tough bands of connective tissue, in your fingers.

That's a myth, as is the one about hair. Dehydration causes a corpse's skin and soft tissues to shrink, making the nails look longer.

Most apes and monkeys can touch their thumbs to their other fingers. Opossums have opposable thumbs, too. Still, you can move your thumb farther across your hand than a non-human primate can.

The difference is determined by this sex hormone early on during a baby's growth in the womb. Most men have longer ring fingers, while the opposite is true for many women.

Crack away! Someone might've fed you this myth because they couldn’t stand the annoying sound. The popping noise you hear isn’t bone on bone -- it’s the bursting of small gas bubbles in the joint. And studies show there's no link between the habit and stiff, painful joints.   

Scientists think hand preference stems from genetics, hormones, and development. Still, two left-handed parents are the most likely combo to have a left-handed child, with odds of about 30% to 40%.

Your nails don't have sensation (otherwise you couldn’t trim them without screaming). But your nail bed is packed with nerve endings and blood vessels. That's why a tap on the nail is felt below.