Call it what your like -- tennis toe, disco foot, jogger's heel. But however you dress it up in the argot and activity of the day, at the foot of it all is that feisty little fertile-crescent ancestor who found that by standing up and peering out across the tall grasses, he'd get a leg up on the neighborhood carnivores.

And then he found he liked it up there. . .

Since most of us still find it useful to stand tall (rather than crawl), here are some steps for keeping you on your toes, in health and comfort.

The foot is, says Dr. Alan E. Singer, podiatric surgeon and co-director of the Georgetown University Sports Medicine Clinic, "the body's most underrated and abused organ."

And whereas the human hand evolved nicely into the useful and versatile tool it is, the foot has lagged badly.

"We have not yet refined ourselves completely from our tree-climbing days," says Dr. Singer, "to where our upright propelling function is evolved, as it will be, say, sometime in our million-year future."

So that's the first problem, and there's not too much to be done there (except wait a millenium or two).

Never mind, there are two more footish problems somewhat more susceptible to preventive steps:

Pavement pounding.

The hard (concrete, wood, stone) unyielding surfaces we mostly walk on, says Dr. Singer, eventually cause "a significant atrophy of the intrinsic muscles of the foot," which in turn cause "a clawing or partial clawing of the toes -- and multiple forefoot dyfunctions."

Ill-fitting shoes.

"Now," says Singer, "I'm not of the school that believes that all foot problems are caused by shoes. Trying to cure a foot problem by changing the shoes is quite often analogous to wearing a hat for a headache."

On the other hand, he notes, "We round out the gamut and produce multiple problems by taking a relatively wide platform-like structure and pressing it into a pre-conceived, last-designed shoe, which may be the antithesis of what is needed for any particular individual."

"It is right that each man should measure himself by his own foot ." -- Aristophanes in "The Birds.""

Podiatry is what you might call a self-made medical profession. A long stride from the old days (only a few decades ago) when podiatrists were regarded as closer to snake oil than surgery, the profession today takes its place with any traditional medical specialty. It mostly requires four years of college and four or more years of graduate-level education and training at one of the five colleges of podiatry in this country.

Then there are board examinations, internships, residencies and respected positions on hospital staffs.

The foot has 26 bones, 33 muscles and "an ungodly number of ligaments and tendons." It can be compared, says Dr. Singer, to "a highly tuned, precise watch. The muscles and tendons and ligaments are in very specific mathematical relationships to each other. The malfunction of any particulal segment can have ramifictions on the whole, including leg, hip, knee and back. . ."

"One thing we try to get across to everybody is that the foot is not an isolated unit, but is very intimately connected with other body functions, particularly neurological and vascular systems. Dysfunctions anywhere else can often show up on the foot." For example: heart, kidney or liver ailments.

Foot problems can be presented as knew, leg, hip or back problems. Or vice versa.

"The foot is often held up as a mirror of the body," says Singer

Helping the foot do its two major jobs -- weight bearing and propulsion:

Walking barefoot on the grass or the sand is not only nice, it's necessary.

(Flexible shoes which permit the exercise of all the muscles in the foot can protect bare feet from bee stings and jelly fish and other unpleasantries lingering in meadow or shore.)

The byword for shoe-buying should be "sensible."

Shoes should be snug in the heel, wide enough at the ball of the foot, long enough for the toes. The tradeoff for high heels is foreshortened hamstrings. The tradeoff for cheaper-than-leather synthetics is the dark, dank, dampness in which fungi (as in athlete's foot) and bacteria (as in infections) grow and flourish.

If you ask Dr. Singer what kind of shoes to buy he'll snap, "Blue."

(Use, in other words, your common sense.)

Something your mother told you that just isn't so: Cutting your toenails in a "V" will prevent ingrown toenails.

Forget it. Cut them more-or-less straight across, natural shape permitting, and don't cut them all the way down to the skin.

Something your mother told you that is so: Wash your feet every day.

Dry them by patting, rather than rubbing. Powder them if they tend to perspire. Oil them if they tend to be dry.

"A pretty foot is one of the greatest gifts of nature . . ." -- Johann Wolfgang von Goethe.

Shoe-leathering season: Remember Adlai Stevenson's hole-in-the-sole campaign?

Political candidates rely as heavily on their feet as anybody. How do they fare? Presidential candidate John Anderson, for one, has already received a pair of shoes as a contribution so he'll have a spare when the soles go on his own.

Babies have delicious feet. When they're not being nibbled on by the babies themselves, they're being nibbled on by doting parents and grandparents. bThey're adorable. They're also full of very soft, unformed bones and muscles and need to be treated accordingly.

If Baby doesn't walk at a year, it may be because those sweet little feet aren't ready. Don't push them. Another six months won't hurt anybody and may mean a helthier toehold when it counts.

Babies' feet also grow enormously fast. Too tight shoes can do irrevocable damage, actually changing the shape of the soft, unformed bones. Check them weekly and change the shoes as often as monthly.

Everybody, of course, knows what our current sports frenzies are doing to feet. Sighs Dr. Singer, "We have a whole system of problems that are developing because of the ill-trained, overextended, amateur athlete."

Mostly what he calls the "overuse syndromes: muscle strains, partial tears, stress fractures of leg and foot, and the development of inflammatory conditions. . .You can call them 'tennis toe' or 'disco foot.'. .each activity has a predilection for producing some particular condition. usually it can also be produced by a thousand other things. . ."

("Tennis toe" is caused by good tennis shoes, actually, in which the traction is so good that the toe keeps skidding into the inside of the shoe, causing a painful bruise.)

Corns, calluses, bunions, blisters and things that go bump on your feet:

Over-the-counter medications, says Dr. Singer, may be useful but temporary expedients. They help symptoms, but the symptoms will keep coming back until the underlying cause is found and eliminated.

"It is as though you were allergic to strawberries and took the medicine for your allergy, but kept eating strawberries. . ."

People with no special health problems would do well to see a podiatrist once every year or two, believes Dr. Singer, because many conditions can be headed off before they become painful, or just annoying.

Diabetics or persons with vascular or neurological problems or post-frost-bite victims or partial amputees must take special care of their feet.They should never sefl-medicate and should see a podiatrist at least twice a year.

For those with no special problems, there is a new and lucid book called "How to Doctor Your Feet Without the Doctor," by Myles J. Schneider and Mark D. Sussman, both podiatrists ($8.95, published by Running Times, Woodbridge, Va.)

Although some of its do-it-yourself tips would make Hercules quail, it can help you distinguish between what ought to hotfoot you to the doctor and what can go soak.

The American Podiatry Association is also a good source of toe tips. Write them at 20 Chevy Chase Circle, Washington, D.C. 20015.