The hand contains more than 20 muscles and joints which perform a multitude of jobs, from writing and gesture to the use of tools and playing musical instruments. The human hand is sometimes portrayed as the pinnacle of evolutionary development, yet both its biomechanics and neural control have major limitations. These occur at a peripheral level (muscle, joint and tendon) and centrally at spinal, cortical and other supraspinal sites. As examples, in the periphery, movement across the full range of possible joint space is limited by the force-length properties of the extrinsic muscles. Further, when the hand is positioned with all but one finger fully flexed, then that finger cannot be moved by volition at its distal joint – it is disengaged from central drive and effectively paralysed. At the level of the muscle-tendon unit, especially for the multi-tendoned extrinsic flexor and extensor muscles, there can be constraints introduced by the architecture of the motor unit territories, the connections between tendons, and there is the potential for some lateral transmission of force, both within and perhaps between muscles. At a central level, it has long been recognised from studies in non-human primates that there are limits in the ability of the corticospinal system to activate the motoneurones of individual muscles. The degree of common descending drive to muscles can be examined in humans by measurement of the correlated firing of pairs of motor units. This and other experimental approaches suggest that the capacity for selective activation of a muscle is greater for the distal intrinsic muscles compared to the proximal extrinsic muscles. In addition, there have been a number studies of the degree to which forces can be produced voluntarily at joints of one finger with or without forces being produced involuntarily in the neighbouring digits. These have led to two concepts: ‘enslavement’ of force when force inadvertently appears at unintended digits (even in weak efforts); and ‘deficits’ of force when maximal voluntary force is less than expected when more than one digit is used. These properties of the hand motor system differ for movements into flexion and extension. They favour preferential extension of the fingers together to lift them from an object but favour flexion of individual fingers to contact an object. This organisation of neural drive and force distribution in humans allows the specialised tactile surface of the finger pads to explore and grasp objects. For common operations, the hand moves seamlessly through joint ‘space’ and we have little awareness of the neuromechanical limitations imposed at different levels. This highly evolved ability likely reflects the flexibility of corticofugal output to the motoneurone pools.