Hands up for creation!
One morning I energetically participated in rowing practice. With seven other oarsmen I pulled my hardest on the oar to move the boat briskly through the water. As soon as the practice was through, I was contacted by a nearby hospital and I was asked to come in urgently and attend to the needs of a severely injured patient. The deranged fellow had intentionally forced his wrist into a bandsaw in a fit of depression and almost amputated his hand.
How now was I to repair the delicate structures involved, having just pulled with all my might against an oar? Would my hands be steady enough to accomplish the task?
Surprisingly, I was able to manipulate with relative ease micro-sutures finer than a human hair. The divided arteries were soon repaired and the hand regained a healthy pink colour. After repairing the nerves, tendons, and other divided structures, I returned home to ponder the events of the morning.
How is it that our hands can lift huge weights, and also detect the landing of a small insect or the brush of a feather? Why are the arteries located on the palmar side of the hand in such a way that they are not choked off as we grasp heavy objects? How interesting it is that the radial and ulnar arteries at the wrist pass into the palm where they form dual arcades that allow continued blood supply to the tissues even when objects are grasped!
And how is it that the paired digital arteries to each finger are so enveloped with ligamentous supports that they will not kink off during finger flexion (bending)? Why is it that the low-pressure venous system is primarily located on the back of the hand where restriction of blood-flow would not occur with grasp?
Many surgeons have devoted countless hours to developing some understanding as to how blood flows to the small bones within the wrist. The built-in servo-mechanisms which regulate blood-flow to the hand in response to tissue needs are only now beginning to be understood.
Survival of the fittest is one of the basic tenets of evolutionary theory. The animal or human with the greatest ability to fight off its contemporary should theoretically survive. Why then do we not have hands more suited for this battle? Why have we not developed claws, or spurs, or protective armour plates?
I have cared for a number of individuals who have abused their hands in fighting. Metacarpal fractures (those which occur in the hand between the wrist and fingers) and extensor tendon injuries frequently result from boxing. Disruption of the skin over the knuckles from striking an opponent’s tooth has resulted in severe and permanently incapacitating hand infections. A ‘human bite’ so obtained requires immediate admission to the hospital. How could our ‘transitional form’ ancestors have survived unless they had the intelligence from the very beginning to don appropriate armour—or perhaps the good sense to avoid the fight altogether?
In biology classes in days gone by we would often talk of ‘teleologic’ reasons for certain observed structures. (Teleologic refers to a purposeful design.) In other words, form reflected function. That our hands function well in activities ranging from mountain climbing to threading a needle, but function poorly in fighting, suggests, teleologically of course, that our hands are best suited for noble endeavours that have no evolutionary survival value whatsoever.
Rowing, anyone?
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