Manual Training: A Brief Refresher Course in Both Hands

 

“The slender expressive fingers, forever active … came forth and became the piston rods of his machinery of expression.”

—Sherwood Anderson, “Hands”

 

 

There are thirty-two muscles in each of your hands. Contrary to what you may think, there are no muscles in your fingers—only tendons and bones. The muscles that operate your fingers are located in the forearm and palm. It takes ten muscles to move the thumb, six to eight to move each of the other fingers.

Human beings employ two main kinds of grips with their hands: the power grip and the precision grip. To get an idea of each, just imagine opening a jar. At first you use a power grip to loosen the cap. Once the cap is loosened, your hand instinctively changes to what is called a precision grip to remove it completely.

The average firm handshake—a sort of modified power grip—exerts approximately 90 pounds of pressure, though some over-enthusiastic handshakers may wind up squeezing your hand with as much as 150 pounds of pressure. (Author Margaret Halsey once wrote of an acquaintance, “His handshake ought not to be used except as a tourniquet.”)

Look closely at the backs of your hands. In each square inch (p. 46) of skin, there are more than 300 sweat glands, 35 hair follicles, 10 feet of blood vessels, and 9, 000 nerve endings.

The tips of your fingers are some of the most sensitive parts of the body: the skin there is packed with an unusually high density of sensory nerve receptors. Some people who are blind develop such a highly refined sense of touch that they are actually able to “read” the letters—just the slight elevation caused by the ink—on a normal page of text.

Of all human hands, the longest on record measured twelve and three-quarters inches from the wrist to the tip of the middle finger, and belonged to modern giant Robert Wadlow (1918—1940), who stood eight feet, eleven inches tall.

The largest known hand span of any human being was that of left-handed composer and pianist Sergei Rachmaninoff, who could cover twelve white keys on the piano with one hand. Rachmaninoff could play a chord of C, E flat, G, C, and G with his left hand.

In most people, the middle finger is by far the longest.

Animals with six digits on each paw are relatively common. A domestic cat with six toes, for example, is not unusual, and even among people the phenomenon is by no means unheard of.

Roughly three out of every thousand people are born with a congenital condition known as syndactyly, in which there is webbing between the fingers. The condition is more common among men than among women.

Fingernails are dead tissue composed of a substance called keratin, a protein that is also found in hair, feathers, horns, and beaks. Nails are said to grow slightly faster on the dominant hand. They also grow faster in the summer than in the winter. (Constant nail biting may also spur their growth.) During an average lifetime, each finger will produce approximately twelve feet of nail.

Any serious illness can leave tiny horizontal lines—called “Beau’s lines”—on your nails. Even severe emotional disturbances, such as chronic depression, can ruin or have an impact on the nails.

Brittle, cracked nails are often a sign of nutritional deficiencies. (p. 47) Opaque, white nails may be a sign of liver disease. Separation of the nail from its bed can be an indication of hypothyroidism.

Constantly cold hands can also be a sign of thyroid problems.

What we call fingerprints are actually tiny ridges of flesh, much like the tread on a tire, which improve our ability to grasp and hold objects. Even identical twins do not have the same fingerprints, though at first glance their prints tend to look quite similar, there are, however, minute differences in the ridges.

Fingerprints were first used as a means of identification by the Chinese as early as 200 B.C. Their widespread use in criminal investigations, however, did not come until 1901, when fingerprinting of criminals was officially adopted by Scotland Yard.

The prefix chiro- is generally used to indicate any technical terms having to do with the hands. For example, the vast majority of people are chirognostic—that is, they can tell their left hand from their right. (There are some people with perceptual disabilities who can’t.) Handwriting is technically known as chirography. And a chiropractor is one who practices medicine with the hands.

Palmistry—the art of reading the past and the future through the lines and shapes of the hands—is technically known as chiromancy, and may have been practiced as far back as the Stone Age. Aristotle, Napolé on, and Alexandre Dumas all had a fascination with the subject.

Better to study a palm, though, than to eat it: among some aboriginal tribes in Australia, it was common to eat the palm of a slain enemy and thereby supposedly ingest some of his physical prowess.

In 1632, an Italian named Camillo Baldi developed the first principles of graphology: that is, trying to determine people’s character traits and personalities from samples of their handwriting. Among some of history’s most ardent amateur graphologists were Edgar Allan Poe, Thomas Carlyle, Goethe, and Disraeli.

Some common examples of graphological analysis: a very small capital I may indicate that you have an inferiority complex; handwriting with no slant (leaning neither to the left nor to the right) indicates a cool-headed, often judgmental person; if you (p. 48) do not completely cross yor T’s, you may be prone to procrastination.

The first widely accepted manual alphabet (sign language) for the hearing-impaired was developed by Charles Michel, Abbé de l’É pé e, at his school for the deaf in Paris in the late 1700s. Today, sign language is the fourth most frequently used language in the United States, outranked only by English, Spanish, and Italian.

According to cultural anthropologists, all human beings have a “vocabulary” of literally thousands of hand gestures, each one communicating a nuance of exasperation, affection, frustration, happiness, despair, or amusement. In fact, some researchers believe that the number of expressive hand gestures far exceeds the number of spoken words in our vocabulary.

For whatever reason, some hand gestures seem to transcend time and cultural differences. For example, the ancient Romans called the middle finger impudicus—“the shameless finger”— because even then it was frequently used to express derision and annoyance. (p. 49)

 

 

5. Ambidextrous Apes and Left-Handed Blonds: Clues to the Causes of Left-Handedness

 

“O investigator, do not flatter yourself that you know the things nature performs for herself.”

—Leonardo da Vinci

 

 

The origins of left-handedness remain a mystery.

In the fourth century B.C., Plato theorized that all people were born ambidextrous and that it was only because of “the folly of our nurses and mothers” that children were pressured into choosing one hand over the other.

The playwright Aristophanes, a contemporary of Plato, had his own poetic conjecture: people, he said, were originally created round like apples, with no fronts or backs, no left or right; Zeus, in a fit of pique one day, split everyone in half, and sidedness (as well as the eternal search for our other halves) began.

The quest for an answer to the riddle of left-handedness continued into the Middle Ages, and the theories reflected the times. Left-handedness was caused by the Devil taking possession of one’s soul. Even a brief encounter with the Devil could suddenly make one left-handed (and leave moles, warts, and other marks on the left side of the body).

By the seventeenth century, scientific rationalism had replaced superstition, and many of the explanations began to acquire a seductive patina of medical logic. “Experts” laughed at the (p. 50) imaginative lore of the past—and then calmly asserted that left-handers were simply weak and defective versions of humankind, right-handers being the proper and intended archetype. A lively interest in anatomy also emerged: could left-handedness somehow be related to the internal misalignment of some people’s organs and muscles? The “experts” disagreed.

They still disagree today. Although some of the clues to left-handedness are slowly, finally, revealing themselves to researchers and scientists, the essential enigma of why some people are left-handed remains. And the fact is, when all is said and done, different people may be left-handed for different reasons.

 

Right-Brain, Left-Brain

 

In order to understand some of the theories about left-handedness, it helps to know a few things about the brain first.

The average human brain weighs almost three pounds (slightly more for males, slightly less for females), contains more than 100 billion neurons, and is divided into two very slightly asymmetrical hemispheres, the left and the right, with a complex mass of nerve fibers—the corpus callosum—connecting the two.

The purpose of the corpus callosum—which is, for reasons yet unknown, as much as 11 percent larger in left-handers—seems to be, in part, the facilitation of “communication” between the two hemispheres.

The two hemispheres tend to control different tasks. A vivid example of the way the hemispheres operate can be seen in some stroke victims who, though rendered totally unable to speak, may still be perfectly capable of singing. That’s because the left hemisphere of the brain tends to control many of our verbal functions, while our memory for music is usually located in the right hemisphere. This startling phenomenon was well documented as far back as 1754, when a doctor wrote of one of his stroke patients, “He can sing certain hymns, which he had learned before he became ill, as distinctly as any healthy person. (p. 51) Yet this man cannot say a single word except ‘yes.’” A stroke that affected the left hemisphere might weaken or eradicate person’s ability to remember words or speak them, but would leave the ability to sing some of those same words intact.

Other functions sometimes attributed to the right hemispher includes:

 

spatial sense

depth perception

the ability to recognize faces

the ability to invest speech with meaningful emotional nuances

 

Functions often attributed to the left hemisphere include:

logic skills

a memory for names

the ability to speak and form coherent sentences

the ability to dissect and analyze difficult concepts

 

In years past, it’s been popular to overdramatize the dichotomy between the left and right hemispheres of the brain. The left hemisphere, it was commonly said, can only analyze things in a rigid, logical, sequential manner (much as a computer does), while the right hemisphere tends to absorb and reflect intuitively on what it sees. “Getting in touch’’ with the right side of the brain (allegedly the more mysterious and artistic side) had a certain fashionability for several years.

However, neurologists and brain researchers increasingly tend to view this dichotomy as simplistic and naive. Recent research indicates that brain functions are much more complicated; a proper integration of who we are, our humanness, depends on the two hemispheres side by side. And whereas, for example, the left side of the brain may indeed govern verbal abilities in some people, for other people those same abilities may reside in the right hemisphere or be spread in a complex manner across both hemispheres.

“We’re trying to understand the most complex piece of matter (p. 52) in the known universe, ” brain researcher Jerre Levy, of the University of Chicago, has said. “No complex function—music, art or whatever—can be assigned to one hemisphere or the other. Any high-level thinking in a normal person involves constant communication between the two sides of the brain.”

 

FIVE ABANDONED THEORIES OF LEFT-HANDEDNESS 1. Left-handedness is a willful, neurotic choice made by obstinate and antisocial individuals. Left-handedness, wrote psychiatrist Abram Blau in the 1940s, “is nothing more than an expression of infantile negativism and falls into the same category as... general perverseness.” Left-handers, he added, often come from families in which the mother is cold and inattentive and withholds affection. 2. All people are born right-handed. Some become left-handed because they are mentally or physically deficient and cannot properly learn right-handed skills. 3. Most people become right-handed because their arteries are stronger on the right side of their bodies; therefore, the muscles on the right (including in the right hand) are stronger as well. Left-handers have larger and more efficient arteries on the left side of their bodies. 4. Because the heart was once believed to lie in the left side of the chest, early warriors sought to protect it by carrying their shields with the left hand while holding their clubs and spears in the right. Thus the right hand became the species’ active hand and the left became the passive hand. Left-handed individuals are presumably descended from tribe members who rarely took part in fighting and who instead concentrated on agriculture, art, and other peaceful endeavors. 5. Left-handedness is the result of bad toilet training, in which the child becomes confused over which hand should be used for toilet hygiene and which should be used for other tasks.

(p. 53)

 

“Cross-Wiring”

Human beings are ‘“cross-wired”—that is, the right hemisphere controls the left side of the body, and the left hemisphere controls the right side of the body.

Generally speaking, then, the left hand is governed by the right hemisphere; the right hand is governed by the left—leatfing to the popular T-shirt and coffee mug slogan:

 

“If the right side of the body is

controlled by the left side of the brain,

and the left side of the body is controlled

by the right side of the brain, then

left-handed people are the only ones

in their right minds.”

 

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