A comparison of fingers and hand in varanus, opossum and primates.

A comparative analysis of hands constitutes the basis of an assessment of hand function in an evolutionary context. Terms as functional domain and functional options are instrumental to define the functional expansion, which can be seen when comparing reptiles, opossum and primates. In man the structural arrangement can be interpreted in functional terms only by terms as functional continuum or universe and by performance control. In the great apes knuckle walking and brachiation seems to interfere with a full-fledged pollical-digital interplay, the latter function being considered to constitute the structural base of optimalization collecting afferent information, requiring brain development, which opens up categories as abstraction, design and freedom.