Hands: the cutting edge of the mind

Jacob Bronowski describes hands as ‘the cutting edge of the mind’. Upon further dissection, the statement rather aptly encapsulates the hand. The ‘cutting edge’ design of the appendage, of such complexity, that current prosthetic versions fail to measure up to the original, offers us a dexterous tool to navigate our daily lives with. Hands are vital components of our day to day routine, taking on the role of social cues – which if not controlled betray ones ‘mind’ to others. The anatomical and social implication of the hand have enraptured humanity throughout history, and artistic expression articulates, using the very tool that it depicts, the higher cognitive function of the human mind. In this essay, we shall be taking a whistle-stop tour of the hand beginning with its anatomical design, followed by a sociological exploration of the appendage, to finish with depictions of the hand in art.

The anatomy of the hand

Skeletal Structure

The bones of the hand are arranged into three groups: Carpals, Metacarpals and Phalanges (see figure 1). The Carpals are found in the wrist and are arranged in two rows each with 4 bones (see figure 2): Proximal row (closest to the trunk of the body and forms the wrist joint) and Distal row (closest to the metacarpals). Metacarpals form joints with the Carpal bones called the carpometacarpal joints. The Metacarpals are located at the palm. The Metacarpals form joints with the Phalanges- the bones of the fingers (digits). Each finger has three Phalanges with the exception of the thumb which has two. ( see figure 3)

Muscular Structure

Muscles which originate in the forearm provide power grip whilst those that originate in the hand provide precision grip. Due to the sheer number of muscles and their mind-numbing nomenclature, we shall focus on the intrinsic muscular structures in the hand concerning the little finger and thumb. The little finger has four intrinsic muscles (see figure 4) working on it which are supplied by the ulnar nerve. The thumb’s muscles are similar (there is an additional muscle which adducts the thumb), however, are innervated (stimulated) by the median nerve. The little finger and the thumb are joined by connective tissue (‘Flexor retinaculum’) from which some intrinsic muscles originate.

Hands as social cues

Handshakes have been used by humans since the ancient world, with evidence of the greeting on a statue in Athens of Athena and Hera shaking hands. The origins of the handshake are contested, some arguing that it was to check if each other were carrying weapons, others claiming it was used by Roman generals to decide who was to have first taken at a feast. Either way, it began as an assertion of dominance- the angle of the hand, power and duration of the shake determining a person’s instant impression of their acquaintance. Recently, we have discovered that there is more than an assertion of dominance that passes over a handshake and that chemicals found in sweat transfer between recipients contain a wealth of information that we detect and use. A study in 2015 participants who shook hands with those of the same gender held their shaking hand near their face for longer with heightened airflow after the handshake; this suggests that we extract olfactory information from handshakes. These chemosignals found in our hands convey fear, drive hormonal and behavioural changes and alter brain activity.

Hands and creativity

From the depictions of hands in the ‘Cueva de las Manos’ to Da Vinci’s anatomical dissections, hands have been at the centre of visual art history. One of the most famous pair of hands in Art are those of God and Adam in Michalenko’s ‘Creation of Adam in the Sistine Chapel (see figure 7). The connection between Adam and God symbolises the spark of life is created- through the fingers an intense spiritual experience occurs. The expressive movement of the hands is riveting as we are expectant of the moment of contact and yet aware that they are moving away from one another. An alternative take on the scene from an anatomical perspective interprets the angels, whose organisation bears an uncanny resemblance to the cross-section of the brain, gift consciousness to Adam- once again through the extremity. In this painting, hands hold the key to life – a profound realisation of the long term human fascination with the appendage.

Having completed our brief introduction to the humble appendage found at the end of our forearm, we can come to realise the true gravity of Bronowski’s wisdom. Hands are truly a form of ‘cutting edge’ design, whose muscular, skeletal, nervous ( and many other structures ) orchestrate movement in such a manner that bioengineers today are still researching ways to replicate. Furthermore, they act almost as extensions of our minds in communication, allowing us to assert dominance and gain information from our surroundings from the ‘edge’ of our bodies. There seems to be an innate appreciation of the role of our hands ( becoming more scientifically palatable with new techniques and research projects in recent years), that artists have been expressing from prehistoric times; one of the most riveting paintings in western culture is that in which hands take centrepiece and their spiritual value is generated. The hand truly is the cutting edge of the mind.













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