Hands and arms are much more ancient structures than we are, so much that they were already present in amphibians in an almost identical form. They are a perfect example of pre-adaptation to various functions: if in the first amphibians they were a simple point of support, in subsequent forms living on trees, the movement and mobility of the thumb have made them capable of grasping the branches so that they can climb. All mammals living on trees are able to use their hands in this way, but some of them have found other uses: the squirrels use them to bring food to their mouths, monkeys use them even for cleaning the body and to care for the offspring and finally the great apes use them to build shelters and small tools. This was possible thanks to a increasing mobility and coordination of the fingers and especially the thumb, which has evolved becoming able to precisely oppose to the tip of the forefinger.
The ability to manipulate objects has been developed further in humans, whose hands have a more square and less elongated shape compared to monkeys next to him, so that the thumb of man can reach easily and with great speed the tip of each finger; this shows how the main purpose of hands is no more to cling to branches. The number and sophistication of the instruments constructed and used by human hands has become incalculable, so that its most apparent feature is perhaps that of being a manipulator of objects. The importance of this faculty in our lives is obvious.
ROYAL BOX
GIOVAN BATTISTA MORGAGNI