You think losing eyes or legs would be supreme disasters. Losing my partner and me would be a far greater one. I am your left hand. I cannot perform chemical miracles like his liver or electrochemical wonders like your brain. Basically, I am a piece of machinery, a bewildering array of levers, hinges and power sources, all managed by a master computer, man made that is your brain. In complexity, made machines are far behind. I am versatile, tireless, and swift.If you are an exceptional typist, my partner and I could put 120 or more words on paper each minute.
A measure of the importance of any body part is the size of the brain area reserved for its use. We hands have two of the largest spaces in the area of the brain known as the motor cortex. When you rotate your thumb, you are witnessing an amazing event. Thousands of messages from the brain are required for the simple act, ordering this muscle to contract, that one to relax; causing this tendon to pull, that one to rest.
From birth to death we hands are almost never still, except for some rest during sleep. During your lifetime I will extend and flex finger points at least 25 million times. Legs, arms, shoulders, feet and other parts of your body tire with sustained activity. But how often do you complain about tired hands.
Even when you were a baby emerged from the womb, we hands were quite well developed. We were strong enough to support your body weight.Considering the remoteness of many of the muscles that control me in your forearm, my strength is surprising. You can exert a grip of 45 kilos; if you were super strong it might go up to 60 or higher. Women generally have only about half as much grip as a man.
Like approximately 95 percent of other people, you are right handed. You began to choose handedness when you were about six months old. At the same time you began to coordinate hand and eye movement learning to look at something and pick it up. This period was a landmark in your development.
Until man’s forebears assumed upright posture they were among the most defenseless of creatures: a snack for a lion or a tiger, easy prey for a hyena. But once erect posture freed us hands from the job of locomotion, we could fashion and use weapons and tools.
Then the naked ape achieved mastery over the earth and its creatures. Then, too, the jaws, freed of foraging and fighting responsibilities, shrank in size and could begin to experiment with language. As our tasks became more complex, the brain began to grow. You are the end product of all this, can give us much of the credit for starting you up the evolutionary ladder.
The strange thing is that meanwhile not a great deal was happening to us, we are not much different structurally from hands of other primates. But we are infinitely more skilled.
We can even substitute for eyes, ears, voice. If you were blind, you could use us to read Braille. If deaf, you could “speak” with us by using sign language. Our tactile discrimination is so keen that you do not have to look at the coins in your pocket to find a rupee. My fingers can pick one out for you. If you were a farmer, you could test the soil through your hands and determine its texture; if a housewife, you could judge by feeling, the quality of a fabric. These are extraordinary achievements.
We hands can take a certain amount of credit for some important intellectual achievements, too. We played a part in the development of mathematics; the decimal system is based on the ten digits my partner and I possess, as well as your ten toes.
Structurally, we are the most intricate components of your body. In no other part of the body is so much machinery packed into so small a space. I have 8 wrist bones, 5 bones in my palm and 14 in my digits making it a total of 27. Add my partner’s 27 and we account for more than a fourth of the bones in your body. My supply of nerves to detect heat, touch and pain is one of the most elaborate in the body. I have thousands of nerve endings per square centimeter, most heavily concentrated in my fingertips. Sensitivity here is extraordinary. You can feel your way in the dark, moisten a fingertip and determine direction of the wind and do a thousand other things that you considers common place, instead of looking on them as the true wonders they are.
My tendons are the power trains, the connecting linkup between my many jointed bones and the remote muscles which move them. You can feel tendons in your forearm move when you flex a finger. For binding material I have a maze of ligaments, plus fascia, which is a layer of connective tissue providing foundation material for nerves, blood vessels and other components. I don’t have room for a big network of arteries and veins, but I do have a rich network of capillaries. I suffer on a cold day while the rest of your body is quite comfortable because the peripheral nature of my digits-they are far from your heart, allows your blood to cool.