Patterns of static prehension in normal hands.

For the purpose of classifying the patterns of static prehension in normal hands, the finger positions were photographed from 5 directions, while each of 7 normal adults held each of the 98 objects. The contact areas were also photographed from three to four directions. All sets of photographs were compared. Any two were considered identical in pattern when both the finger positions and the contact areas were alike. Fourteen identical patterns were identified: five patterns of power grip, four of intermediate grip, four of precision grip, and one other. Eighty-six percent of the grips shown by the subjects could be fitted into one of these prehension patterns, and the remaining 14 percent into intermediate or combined patterns. For all 7 subjects, 31 of 98 objects were grasped in an identical pattern and the rest of the objects, 67, in 2 or more patterns.