Though many stilettos hover 5 to 8 inches off the ground, a mere 2 inches is a "high heel" to most podiatrists. Heels that tall or higher have been linked to knee, heel, and ankle problems.

In one study, women who wore 2-inch heels 40 hours a week for two years had shorter calf muscles, shorter strides, and other permanent changes that put them at risk for injury.

Doctors don't agree that "natural" running is safer. Barefoot running seems to improve strength and balance, but the lack of protection can cause more puncture wounds and increased foot stress. So, the jury's still out.

Nine out of 10 cases of this common foot deformity happen to women.

The main trigger for bunions is too-tight, narrow shoes -- which 88% of women wear, according to one study. Other causes: unlucky genes, arthritis, and flat feet.

Heel pain -- the No.1 reason people see a podiatrist -- is usually caused by plantar fasciitis, inflamed tissue on the bottom of the foot.

About 90% of cases resolve in two months through home care like ice, NSAIDs, rest, and stretching -- especially if you don't ignore the pain and treat early. Cortisone shots are reserved for tough cases, as overuse can lead to tearing and chronic pain.

Toes that strike the shoe's toe box repeatedly cause trauma and bleeding under the nail. This can happen on hard pavement, or in shoes that are too short or too tight.

Ultrarunners have been known to have all their toenails removed to avoid them banging against shoes. Easier: Head for softer surfaces, make sure trainers fit right, and buy new ones after 9 to 12 months, if you run 10 miles a week.

Morton's neuroma, a benign nerve tumor, is linked to wearing high heels and shoes with tight toe boxes -- so women get it 8 to 10 times more often than men.

It's a thickening of the tissue around a nerve heading between the third and fourth toes. The shooting pain feels like stepping on a hard kernel of corn.

Another surprising cause: positioning your toes abnormally. Golfers, who twist the foot when swinging, are neuroma-prone.

New moms aren't imagining that their old shoes fit no better than their pre-baby jeans. German researchers measured -- and sure enough, found increases in foot length and width after childbirth.

Water retention and post-baby pounds amp up size, and the hormone relaxin literally spreads them out. Alas, feet don't always shrink back even if you lose the baby weight.

Some people are born with flat feet -- the absence of a space or "arch" between the ground and the sole -- but others develop it over time.

Though often painless, a telltale sign is feet that feel achy or tired after standing still for even short periods or after playing sports.

People with flat feet or their opposite -- high arches -- tend to need shoes with extra support.

Other new "foot facelifts" for those who want strappy-sandal-ready feet include toe shortening (to make the second toe smaller than the big toe) and toe straightening (to remove some bone to correct curled or angled toes).

Given that feet have 26 bones and 30 joints, foot doctors warn against surgery on pain-free feet that are working just fine.

Most versions of the summer fashion staple offer no arch support or shock absorption, and lack stability, setting you up for damage.

That's why foot doctors recommend against wearing flip-flops for long periods or during sports. At the pool, though, they can save your feet from fungal infections.

Athlete's foot is a fungal infection that thrives in warm, dark, humid environments (like locker rooms, hence its name). Highly contagious, it can even be spread by sharing sheets with contaminated feet, so wear clean socks in bed if your mate has infected feet.

Military cadets who used a prescription antiperspirant for at least three nights before a long hike had blisters half as often as a control group studied. Drying foot powders, dry soap flakes, and OTC antiperspirant sprays that contain aluminum chloride work, too.

Other studies show synthetic socks wick moisture better than cotton, which promotes irritation when wet. (That's why dancers tuck lamb's wool between toes.)

Corns and calluses are both patches of thickened skin caused by pressure and rubbing. When the patch appears on the side or top of a toe, it's called a corn. When it's on the bottom of the foot, it's a callus.

Plantar warts -- speckled, tough growths caused by a virus -- are often mistaken for corns and calluses.

Typically the very first sign of gout -- a form of arthritis sometimes called "arthritic gout" -- is a suddenly swollen, hot, painful, and ugly-looking big toe.

Gout is caused by too much uric acid, a natural substance. When it builds up, it forms needlelike crystals, especially at low body temperatures. And what's the coolest part of the body, farthest from the heart? The big toe.

Too-short nails invite the surrounding skin to grow up and over the nail. The pressure can really hurt.

Cutting nails in a curved shape is little better; straight across is best.

Don't try to re-trim an ingrown nail or work cotton or dental floss under the nail, setups for infection.

If shoes aren't comfortable in the store, pass on them. About 8 out of 10 Americans say they've had foot pain as a result of poorly fitting shoes, a doctors' survey found. Some people, used to tight shoes, find that "good fits" feel too loose!

To find a perfect fit, have the length and width of your feet measured at the end of the day, to account for normal swelling. Don't buy based on size alone.

Alas, no clinical evidence or studies seem to support this home remedy. Topical or oral medications are the usual treatment.

Pesky, itchy fungal infections are one of the few foot conditions that affect men more than women -- so maybe that's why the idea of wizzing away at the misery has caught on.

Diabetics need regular foot care because the disease causes nerve damage. Nerves to the feet are the longest in the body and most often damaged, making feet numb.

So people with diabetes might not feel cuts, sores, and blisters that can get infected. Foot care reduces amputation rates by half or more.