A classification of manipulative hand movements.

The nature of manual manipulation of objects is discussed. It is argued that a functional distinction should be made between palmar grips which immobilise an object in the hand, and digital patterns which permit manipulation. Such a distinction is separate from any anatomically defined power and precision configurations. Manipulative hand movements may be grouped into three classes, based on differences between sequenced patterns of movement and synergies, the latter being further subdivided into simple and reciprocal patterns. Within each of the three classes, a number of individual movement patterns are described. These differ mainly in the number of digits involved and the way in which the thumb is employed. The classification is concerned with movements of the digits directed at manipulating an object within the hand. It is not concerned with movements of the hand as a whole, using the wrist or more proximal joints, while holding an immobilised object.