For that storied window to the soul, we give you the eyes.
But for a snapshot of physical wellness, a glimmer of hidden health risks, and a peek at natural strengths, we give you the finger.
Now, don’t go away mad: We actually give you all 10 fingers. According to a bevy of recent medical studies, your digits hold clues to disease dangers along with hints of sports prowess, financial acumen and, possibly, your softer side.
This external roadmap of inner secrets extends down to the toes. Yep, those little piggies do squeal, revealing everything from how you’re eating to how your blood is flowing, says Dr. Michael Nirenberg, a foot specialist who practices near Chicago and who founded AmericasPodiatrist.com.
“Toes talk,” Nirenberg said. “They don't rattle on like some annoying relative. They do often mirror overall health — at times being the first place to show signs of serious medical problems.
“Nowadays, with MRIs, CT scans, and hundreds of blood tests to choose from, few doctors look at toes,” he added. “But in ancient times, examining the toes was as important as having patients stick out their tongue.”
So raise a thumb and take a medical hitchhiking tour through 10 traits or health concerns said to be associated with your appendages.
Prostate cancer
Finger length — specifically, whether your index finger is longer or shorter than your ring finger — is a common theme when ascribing illness potential to hand shapes.
Last year, researchers at Britain's University of Warwick published a study contending that men with longer pointer fingers are one-third less likely to develop prostate cancer. They questioned more than 1,500 prostate cancer patients, comparing their hands to those of 3,000 healthy men.
The British scientists suspect that lower levels of testosterone in men with longer index fingers cuts their prostate cancer rate.
Stroke
Take a gander at the "moons" on your finger nails. These white crescents at the base of the nails are technically called the lunulas — the birth place of new nail cells. They are typically most visible on the thumb and progressively smaller (or unseen) on each corresponding finger.
White moons are good.
"If they are purple (however) this indicates internal blood stasis and may be a tip that you are more prone to stroke," said Kristen Burris, founder and medical director of American Acupuncture Center in Eagle, Idaho. "Stasis" means a slowing of normal blood circulation.
For folks with purplish moons, Burris recommends they take 1,200 milligrams of Omega 3 (fish oil) each day to thin the blood (unless you are already on anti-coagulants). She lists three more natural, daily remedies to try: three cups of green tea, two tablespoons of ground flax seeds and — best of all — some red wine.
How much vino?
"Small amounts," Burris said. "The key is to change your health before disease takes over."
Money skills
Men with ring fingers longer than their index fingers may boast inherent business talents.
A 2009 study of 49 male traders at the University of Cambridge in England found that guys with longer ring fingers earned 10 times more money in London’s financial district as compared to men with short ring fingers.
The researchers in that particular study noted that longer ring fingers typically indicate greater fetal exposure to the male hormone androgen, which has been associated with increased aggression.
Empathy
Let’s stick with the fingertips — which may also signal how deeply you feel the pain of others.
This year, scientists in England and the Netherlands proposed that the relative length of index fingers versus ring fingers give away your depth for reading emotions in people. This link, wrote researchers at the universities of Cambridge and Utrecht, seems to be based on how much testosterone you were exposed to in your mother’s womb. This, in turn, can determine your various finger lengths. In general, women are more likely to have longer ring fingers while men tend to have longer index fingers.
For the study, 16 volunteers who received extra testosterone were less able to judge the mood of facial expressions they were shown.
But one American doctor dismisses the study and this theory.
“I do not think it correct to use the term ‘empathy’ as the ability to gauge someone’s feelings from a picture,” said Dr. Kent Holtorf, founder of Holtorf Medical Group, which has offices in Foster City, Calif., Torrance, Calif. and St. Joseph, Mo. One of Holtorf’s specialties is in endocrinology.
“Empathy more involves the ability to put one in someone else’s shoes, with the identification and understanding of another's situation, feelings, and motives” Holtorf said. “The use here is likely misunderstood that the use of testosterone makes one more uncaring.”
You're not eating right
Spoon-like or flat toenails may mean you lack certain B vitamins, Nirenberg said.
Fraying toenails could indicate you’re low on vitamin C. And small, white patches on toenails could mean your body is starving for more zinc.
Heart problems
If hands and feet show bulging, purple veins or spider veins, it could warn that your heart is sick or that your circulation is poor, said Burris.
“Believe it or not, the health of your fingers and toes could be a preemptive clue as to the health of your heart. Fingernails and toenails that split, flake or peel could be a sign that you are blood deficient — even if labs show you aren’t anemic,” Burris said.
“Being blood deficient can lead to malnutrition of your external body leaving your hair, skin and nails dry,” she added. “This malnourishment is also occurring within your body creating a weaker heart, lower blood pressure and fatigue.”
Breathing troubles
People with “clubbed” or rounded fingernails are sometimes found to be suffering from emphysema or lung cancer, says the Mayo Clinic.
In such diseases, stale air becomes trapped inside the lungs, weakening the flow of healthy oxygen to the extremities. In time, this can cause fingernails to curve downward and fingertips to become bulb shaped.
Sports stardom
Check that fourth digit again: Men whose ring fingers are longer than their index fingers seem able to run faster, according to researchers at Britain’s University of Southampton.
In their study, published in 2009, the Southampton scientists examined 241 teenage boys who participated in a sports competition in Qatar. The hands of each runner were measured and the boys were subsequently timed in 50-meter sprints.
The reason for higher speed of the boys with longer ring fingers: once again, higher testosterone levels, the researchers reasoned.
Aches in your future
That stubby index finger is really turning into a villain.
People whose pointer fingers are shorter than their ring fingers also carry a heightened risk of osteoarthritis, according to a 2008 study conducted at the University of Nottingham in England.
(Yes, it might be time to ask: What’s with the Brits’ and their fascination with finger sizes?)
The Nottingham scientists looked at the hand formations of more than 2,000 people and saw a pattern: those with shorter index fingers are up to twice as likely to suffer from the most common form of arthritis. Likely, this is related to the person’s hormones, including estrogen levels.
Boss potential
This is far more myth than science, say modern doctors. But for centuries, folklore held that if your second toe was longer than your big toe, you would (or should) be the head of your family. You had inborn leadership abilities.
In science, this anomaly is called "Morton's toe," and all that doctors have been able to deduce is this foot structure can lead to excessive pressure behind the second toe at the ball of the foot, sparking chronic pain.
So, is there any truth to the ancient legend that a taller second toe means bigger things are in store for you as a top dog?
We again turn to Michael Nirenberg, who has examined thousands of feet in his lifetime.
“I have not seen,” Nirenberg said, “any proof of this.”
Bill Briggs is a frequent contributor to msnbc.com and author of the new, nonfiction book, "The Third Miracle."