Scientists simulated the change of the primate hand into the human hand.

Scientists may have solved the mystery of how human hands became nimble enough to make and manipulate stone tools.

The team reports in the journal Evolution that changes in our hands and fingers were a side-effect of changes in the shape of our feet.

This, they say, shows that the capacity to stand and walk on two feet is intrinsically linked to the emergence of stone tool technology.

The scientists used a mathematical model to simulate the changes.

Other researchers, though, have questioned this approach.

Campbell Rolian, a scientist from the University of Calgary in Canada who led the study, said: “This goes back to Darwin’s The Descent of Man.

“[Charles Darwin] was among the first to consider the relationship between stone tool technology and bipedalism.”

“His idea was that they were separate events and they happened sequentially – that bipedalism freed the hand to evolve for other purposes.”

“What we showed was that the changes in the hand and foot are similar developments… and changes in one would have side-effects manifesting in the other.”


Shape-shifting

To study this, Dr Rolian and his colleagues took measurements from the hands and feet of humans and of chimpanzees.

Their aim was to find out how the hands and feet of our more chimp-like ancestors would have evolved.

The researchers’ measurements showed a strong correlation between similar parts of the hand and foot. “So, if you have a long big toe, you tend have a long thumb,” Dr Rolian explained.

“One reason fingers and toes may be so strongly correlated is that they share a similar genetic and developmental ‘blueprint’, and small changes to this blueprint can affect the hand and foot in parallel,” he said.

With this anatomical data, the researchers were able to create their mathematical simulation of evolutionary change.

“We used the mathematical model to simulate the evolutionary pressures on the hands and feet,” Dr Rolian explained.

This model essentially adjusted the shape of the hands or the feet, recreating single, small evolutionary changes to see what effect they had.

By simulating this evolutionary shape-shifting, the team found that changes in the feet caused parallel changes in the hands, especially in the relative proportions of the fingers and toes.

These parallel changes or side-effects, said Dr Rolian, may have been an important evolutionary stem that allowed human ancestors, including Neanderthals, to develop the dexterity for stone tool technology.

Robin Crompton, professor of anatomy at the UK’s Liverpool University, said the study was very interesting but also raised some questions.

“I am not personally convinced that the foot and hand of chimpanzees are a good model [of human ancestors’ hands and feet] – the foot of the lowland gorilla may be more interesting in this respect,” he told BBC News.

He pointed out that there was a lot more to the functional shape and biomechanics of the human foot than just its proportions.

Paul O’Higgins, professor of anatomy at the Hull York Medical School, UK, said: “The results are quite exciting and will doubtless spur further testing and additional work.”

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The ‘Vitruvian Man’ – Leonardo da Vinci‘s famous drawing from the year 1487 – can be described as one of the earliest sources presenting guidelines for hand anthropometry. Today, plays hand anthropometry a considerable role in the fields of design, ergonomics, and even architecture! An update presenting data from e.g. the NASA and the US army.

The drawing, which is in pen and ink on paper, depicts a male figure in two superimposed positions with his arms and legs apart and simultaneously inscribed in a circle and square. The drawing and text are sometimes called the Canon of Proportions or, less often, Proportions of Man.

Interestingly, Leonardo’s comments for the proportions of th e ‘Vitruvian Man‘ includes a few passage where the hands and fingers are mentioned, quote:

“For the human body is so designed by nature that the face, from the chin to the top of the forehead and the lowest roots of the hair, is a tenth part of the whole height; the open hand from the wrist to the tip of the middle finger is just the same; the head from the chin to the crown is an eighth, and with the neck and shoulder from the top of the breast to the lowest roots of the hair is a sixth; from the middle of the breast to the summit of the crown is a fourth. If we take the height of the face itself, the distance from the bottom of the chin to the under side of the nostrils is one third of it; the nose from the under side of the nostrils to a line between the eyebrows is the same; from there to the lowest roots of the hair is also a third, comprising the forehead. The length of the foot is one sixth of the height of the body; of the forearm, one fourth; and the breadth of the breast is also one fourth. The other members, too, have their own symmetrical proportions, and it was by employing them that the famous painters and sculptors of antiquity attained to great and endless renown. Similarly, in the members of a temple there ought to be the greatest harmony in the symmetrical relations of the different parts to the general magnitude of the whole. Then again, in the human body the central point is naturally the navel. For if a man be placed flat on his back, with his hands and feet extended, and a pair of compasses centred at his navel, the fingers and toes of his two hands and feet will touch the circumference of a circle described therefrom. And just as the human body yields a circular outline, so too a square figure may be found from it. For if we measure the distance from the soles of the feet to the top of the head, and then apply that measure to the outstretched arms, the breadth will be found to be the same as the height, as in the case of plane surfaces which are perfectly square.”
 

'Study of arms and hands' - another drawing by Leonardo da Vinci.

 Leonardo da Vinci’s comment about the proportion of the average hand was quite right, but the field of anthropometry has later developed more precise methods in order to describe the most important individual variations concerning the human body. Various sources of anthropometric hand data indicate the average hand length is close to 11% of body height (usually slightly smaller). Leonardo’s ‘Study of arms and hands’ is another of his drawings.



ANTHROPOMETRY TODAY:

Today, anthropometry plays an important role in industrial design, clothing design, ergonomics and architecture where statistical data about the distribution of body dimensions in the population are used to optimize products.


DATA FROM THE NASA & US ARMY:

In the last decade of the 20 century reports became available developed by the NASA & the US army – which include data for at least 20 characteristics of the human hand shape, including e.g. hand length, hand breadth & finger length. The data in the picture above represents static human physical characteristics of the adult hand, presented in 2000 by the Department of Defense Human Factors Engineering Technical Advisory Group.

The picture below presents at the bottom some average data based on German, UK & American populations – which provide useful ‘points of reference’ in the perspective of biometry & Multi-Perspective Palm Reading.


Finally, regarding Leonardo da Vinci it might be interesting to notice here that in 2008 a report was published describing characteristics of his fingerprint:

http://www.handresearch.com/news/leonardo-da-vinci-fingerprint.htm

Sweat drops in the pores of the skin ridges (dermatoglyphs)

Many people sometimes wonder about the function of their ‘fingerprints’. Why do we have them? The answer is foundstarts in the sweat pores!

As you probably know, the whole body is featured with sweat pores (featured with eccrine sweat glands) – except for the lips & the sexual organs.
 
But in the hands & the feet the sweat pores have a highly specialized role. Because in the inner palm and on the sole the sweat pores manifest on so-called ‘friction ridge skin’ – the so-called skin ridges (see the picture above) that became especially known in the perspective of the fingerprints.
 
Skin ridges & grooves!
 
In the skin ridges the sweat pores are found – in a fingerprint the ridges manifest as the ‘black lines’ and in a high quality fingerprint one can sometimes even see the sweat fore: see the picture below!
 
The surrounding ‘grooves’ serve as a transport channel to distribute the sweat through the hands & feet. And the combination of these element prevent our hands & feet to become ‘slippy’!
 
Because skin friction arises from the interaction between the sweat & the skin of the body, and is directly related to the area of the surface of the body that is in contact with the fluid. An important feature in order to have effective ‘grip’ in your hands!
 
“But keep your head cool, otherwise your sweat glands will start produce too much moisture resulting in a reduced grasp stability!”
 
 
Learn more about the life in the skin of your hand:

Discover 20 skin-facts you didn’t know – including hands, fingerprints & dermatoglyphics!

 

A Valentine’s Day gift idea: surprize your love a hand-massage!

Trouble is, massage, as simple as it sounds, can be fraught with expectation. How to get it just right for your Valentine love? Massage therapist Rekha Von Ehren provided easy reflexology massage tips, and you can learn them by heart today!

VALENTINE MASSAGE TIP 1:

Be inconsistent. Touch your partner with your fingertips, knuckles, elbows, the full palm and the heel of your palm. Likewise, while touching, use a variety of strokes – from deep rubbing and kneading to tickling and light scratching. And feel free to lean in close, using your body weight to add force.

VALENTINE MASSAGE TIP 2:

Reflexology says that the hands and feet are microcosms of the body. When tenderly caressed, hands and feet can signal the interior of the body. So, in theory, you can touch a person’s heart by massaging the ball of the left foot, or tap into your beloved’s brain by massaging the big toes.

VALENTINE MASSAGE TIP 3:

Hands, full of nerve endings, are incredibly sensitive. So massage each finger along the joint to the tip with your fingertips or, perhaps, lips and mouth.

MORE ABOUT PALM THERAPY & HAND REFLEXOLOGY :
Valentine’s Day idea: give your love a massage!
The benefits of hand & foot reflexology!
The basics of palm therapy & reflexology!

 In 1988 a very unusual hand therapy became available at various Spa centers in the world, named: ‘Doctor fish’. Doctor fish are a species called Garra Rufa (and Cyprinion Macrostomus) – which originate in pools near two small Turkish towns, Kangal and Sivas. In non-medical contexts, Garra rufa is called the reddish log sucker. They have long been known for their ability to treat the symptoms of skin conditions, especially: psoriasis!

“Doctor fish” – so named for their ability to produce healthy, glowing results from even the most crusty or diseased epidermis – are the key ingredient in a spa and skin treatment becoming increasingly popular across Turkey, Japan, China, Europe and the US.

The idea is that you immerse your hands, feet, or, if you are brave enough, your entire body in a warm pool that swarms with hundreds of hungry minnow-sized feeders. The fish zoom in on your most crusty, flaky or scabby skin and chomp away at it to reveal the fresh layer beneath. According to the spas and their enthusiasts, you emerge refreshed, healthy, buffed and glowing.

SUGGESTION FOR FURTHER READING:
Let’s shake hands with the hand fish!
Into the hands of ‘Paul the Octopus’!
The mystery of the five fingers!
Five things that your 5 fingers can tell you!
The difference between the human hand & the hands of primates!

Evolution: from fish to human!

The pink handfish - a.k.a. brachionichthys

TRIBUTE: THE EVOLUTION OF THE HAND

[tweetmeme source=”handresearch” only_single=false] A few weeks ago (may 2010) Australian researchers Daniel Gledhill & Peter Last from the CSIRO Wealth reported to have discovered 9 new species of the ‘handfish’, in a research that highlights an urgent need to better understand and protect the diversity of life in Australia’s oceans. But the major unanswered question is: ‘two of the handfish fins look like hands, but are they?’

Mr Gledhill described the Handfish as follows:

“Handfishes are small, often strikingly patterned or colourful, sedentary fish that tend to ‘walk’ on the seabed on hand-like fins, rather than swim. Fifty million-years ago, they ‘walked’ the world’s oceans, but now they exist only off eastern and southern Australia“.

One of the newly named species, the Pink Handfish, is known from only four specimens and was last recorded off the Tasman Peninsula in 1999.

Interestingly, if we take a look at some features of red handfish one can notice that it actually isn’t walking with the hands… but with the feet! (See the photos below)

The red handfish - a.k.a. brachionichthys politus!

And in the perspective of evolution it might actually make sense that the hands of the handfish appear to have 4 digits, and the feet have more digits – though 6 digits is really rather remarkable.

Why are 6 digits remarkable?

First of all, the 4-digit hand combined with a 6-digit foot reminds us to a typical characteristics of… amphibians, they are usually featured with 4 digits on the front limbs and 5 digits on the hind limbs!

However, while an amphibian usually spends his live some time on land and some time in the water – there is another rather funny ‘creature’ that has likewise hand- (4 digits) and foot characteristics (5 digits), named: the axolotl – a tiger salamander complex that is living in the waters of Mexico. The difference with the salamander is that the axolotl only lives in the water, just like the handfish!

The axolotl - belonging to the tiger salamander complex!

Most vertebrates have 5 digit limbs!

One should also be aware that most vertibrates (including: mammals, birds, reptiles, amphibians, and various fishes) have 5 digits on each limb. So, from the perspective of evolution it is not a coincidence that us human have 5 finger and 5 toes!

However, in this perspective it is rather remarkable that the handfish appears to have a 6 digit fin!

Would you like to shake hands with a handfish?

Evolution animation: from fish to human!

SUGGESTION FOR FURTHER READING:
The mystery of the five fingers!
Five things that your 5 fingers can tell you!
The difference between the human hand & the hands of primates!

Evolution: from fish to human!

The evolution of hand & foot.

Is the mystery about the evolution of the human hand solved?

What did Charles Darwin say about hands & feet?

Scientists from Canada may have solved the mystery of how human hands became nimble enough to make and manipulate stone tools – it may be a side-effect of evolutionary changes in our feet!

A BBC report describes that the discussion continues – for other scientists now question the mathematical model which was used to simulate the changes between the hands & feet of chimpanzees and humans. Campbell Rolian, a scientist from the University of Calgary described:

“This goes back to Darwin’s The Descent of Man. “[Charles Darwin] was among the first to consider the relationship between stone tool technology and bipedalism.”

“His idea was that they were separate events and they happened sequentially – that bipedalism freed the hand to evolve for other purposes.”

“What we showed was that the changes in the hand and foot are similar developments… and changes in one would have side-effects manifesting in the other.”

“So, if you have a long big toe, you tend have a long thumb.”

“One reason fingers and toes may be so strongly correlated is that they share a similar genetic and developmental ‘blueprint’, and small changes to this blueprint can affect the hand and foot in parallel. We used the mathematical model to simulate the evolutionary pressures on the hands and feet.”

SUGGESTION FOR FURTHER READING:
The evolution of the human hand!
Five major differences between the primate hand & the human hand!
Primate hands: finger length linked with social behavior!
Beagle report: Charles Darwin had the long pointer finger
The six digit man – hand satire from the Bill Gates Medical Center!

The primate foot & the human foot.
The primate foot & the human foot.

The hand-foot syndrome includes: a chronic inflammation of the palms, and possibly: missing fingerprints!

The ‘hand-foot syndrome’ can be understood as a side effect of a chemotherapy – especially the cancer drug Capecitabine (Xeloda) is notorious for the side-effects related to the ‘hand-foot syndrome’.

Last month (may, 2009) a letter from a doctor, published in the magazine ‘Annals of Oncology’, became hot news because his client – a 62-year old cancer patient from Singapore – was held for four hours by immigration officials in the United States because they could not detect his fingerprints! The doctor of the patient had to declare that his patient’s fingerprints disappeared because of a cancer-drug he had been taking for over years. A disappearing fingerprint is one of the typical but rare features of the ‘hand-foot syndrome’.

The major symptoms of the hand-foot syndrome include: feelings of tingling or burning, redness, flaking, swelling, small blisters, and small sores on the palms of the hands or soles of the feet.
Especially the ‘flaking’ aspect which can result in breaking or peeling of the skin, may result sometimes in the vanishing of the fingerprints.

WHAT DRUGS MAY CAUSE THE ‘HAND-FOOT SYNDROME’?

The following chemotherapy drugs (usually used to treat cancer) have been reported to cause hand-foot syndrome in some patients:

>> Capecitabine (Xeloda)
>> Cytarabine (Cytosar-U)
>> Floxuridine (FUDR)
>> Fluorouracil (5-FU)
>> Idarubicin (Idamycin)
>> Liposomal doxorubicin (Doxil)

INTERESTING SUGGESTIONS RELATED TO HANDS & CANCER:

Why a cancer patient may have no fingerprints: the hand-foot syndrome!
Can palm reading pick up ovarian cancer?
Raynaud’s syndrome – another painful hand disorder
Paraesthesia: feels like having pins and needles in the fingers
Research: dermatoglyphs & gastric cancer (Croatia, 2003)

New researchs points out: fingerprints are unlikely to increase grip to our hands.

In may 2009 Dr Roland Ennos and his team at The University of Manchester presented fingerprints findings with a surprizing outcome. Fingerprints do not help primates grip, as previously thought. Instead, a fingerprint actually reduces the friction needed to hold onto flat surfaces.

Dr Ennos disproved the long-held assumption that fingerprints help primates to grip with a simple machine, three strips of perspex and the right hand of Masters student Peter Warman. They tested the student’s grip on every finger + thumb at three different widths of perspex as the machine pulled the perspex strips down via a weight in a plastic cup. The researchers also tested grip at three different angles by bending both the fingers + the thumb. This wide range of testing conditions allowed them to separate pressing force from the contact area and overcome any confounding variables.

The results indicate that fingertips act more like rubbers than hard solids; their friction coeficient fell at higher normal forces and friction was higher when fingers were held flatter against wider sheets and hence when contact area was greater.

WHY DO WE HAVE FINGERPRINTS?

Dr Ennos answers the question as follows:

“The experiment was so simple, this discovery could have been made 100 years ago; but scientists make assumptions and tend to look at complicated things instead.

My preferred theory is that they allow the skin to deform and thus stop blistering. That is why we get blisters on the smooth parts of our hands and feet and not the ridged areas: our fingerpads, palms and soles.”

SUGGESTIONS FOR LEARNING MORE ABOUT FINGERPRINTS:

The latest news about fingerprints!
Evolutionary hand analysis: the mystery of the 5 fingers!
20 Facts about your fingerprints, skin & dermatoglyphics!