Why the hand?

Surely all neuromuscular systems are complex, and complex enough that our understanding of them (e.g., as described in this book) is universally regarded as challenging. Nevertheless the neuro-musculo-skeletal complexity of the human hand has an aura of being somehow different to that of limbs, and somehow vital to our identity as a species. In fact, the naming of our palenteological lineage emphasizes two biomechanical and one cognitive milestone: homo erectus, homo abilis, and homo sapience, where abilis suggests the manual ability for tool making as a critical evolutionary stage. A reasonable question is, therefore, whether and how the neuromuscular control of the human hand is different from other neuromuscular systems in our body, or other species even. This short Introduction attempts to provide a perspective from which to understand the breadth and depth of today’s lines of inquiry on the neuromuscular control of the hand. As such, it is incomplete and does not do justice to the many investigators currently working in this field, of which the four chapters of this section are only a small sample. Thus my sincerest apologies to those I do not mention in this short overview. As a form of imperfect excuse, I suggest that a reason why it is impossible to do justice to all investigators and lines of inquiry is because the sensorimotor versatility of the hand spans an uncommonly large number of dimensions. Few other neuromuscular systems in our bodies can claim to being important to our biomechanical, manipulative, perceptual, cognitive, psychological, social, linguistic, and artistic everyday activities. The role of the hand in the evolution of the physical and cognitive features of our species is a subject of longstanding interest and intense debate (Brand and Hollister 1999; MacKenzie and Iberall 1994; Napier 1956; Tubiana 1981; Winslow 1732; Zancolli 1979 and references therein). Aristotle gives us a synopsis of this debate as far back as c. 350 B.C.E. by saying ‘‘. . .Now it is the opinion of Anaxagoras that the possession of these hands is the cause of