|The word ‘hand’ hardly needs explaining as a noun.
Everyone knows what a hand is, where it is, what it looks like and what
it does. And it what it does or what hands can do that is so amazing. We
take for granted every movement of our hands during our daily lives. We
speak of hand workers, people who actually work with their hands. From
the navvy who digs ditches, to the joiner who fashions fine furniture.
We speak of handicrafts, generally meaning the making of decorative
items. And we speak of handmade, hand painted, handwritten and numerous
other words beginning with hand.
||However, effectively we are all hand workers,
irrespective of what we are engaged in. We all use our hands to a far
greater extent than we realise and many hand movements are automatic. It
is also incredible to what extent hands can be trained. Just think of
the finger speed of a musician, or the clever sleight-of-hand of a
conjurer. These pictures illustrate just a fraction of what hands are
used for and what hands are capable of.
Hands are very important to the sense of touch, which is the first of
the senses to develop in a baby and is even operating inside the womb.
In layman’s terms the sense of touch works like this: the human body has
about five million sensory nerve receptors on the skin, which send
electrical pulses to special cells called ‘neurons’. The neurons relay
the signal to the spinal cord, which passes it to the brain. This
‘somatosensory system’ probably evolved to protect the body by it
experiencing sensations like pain or heat, causing the individual to
take action to end the feeling.
|The hands use a disproportionate
amount of the somatosensory cortex, that part of the brain that
interprets what we are sensing. This fact shows the importance of hands
in the physiology of the senses.
Hands began to evolve from fins about 400 million years ago, and the
fingers emerged later. By 340 million years ago vertebrates were walking
around on land with five distinct fingers, where previous species had
had seven or even eight. Today all primates apart from spider monkeys
have five fingers on each hand. Humans and some apes such as chimpanzees
are able to pinch objects between thumb and forefinger, giving them a
high level of dexterity in handling small objects and performing complex
tasks with their hands.
Humans have been making artistic images of hands for at least 10,000
years. The Cave of Hands in Argentina contains images of hands made by
spraying paint through bone pipes to make a silhouette of the hand on
the cave wall. Leonardo da Vinci and other Renaissance artists filled
sketch books with studies of hands, and hand gestures were very
important in their paintings. One of the most well-known of these
depictions of hands in art is from ‘the creation of Adam’ on the ceiling
of the Sistine Chapel by Michelangelo, where the fingers of God the
Father and Man touch in a loving gesture.