Want to make a simple, ten-second check on the state of your health? Sneak a peek at your feet.

"You can detect everything from diabetes to nutritional deficiencies just by examining the feet," says Jane Andersen, DPM, president of the American Association of Women Podiatrists and a spokeswoman for the American Podiatric Medical Association.

The lowly left and right provide plenty of insightful data: Together they contain a quarter of the body's bones, and each foot also has 33 joints; 100 tendons, muscles, and ligaments; and countless nerves and blood vessels that link all the way to the heart, spine, and brain.