POSITIONAL PATTERNS FOR PREHENSION IN NORMAL HANDS

For the purpose of classifying static prehensile patterns, the positions of the fingers and the contacting areas which seven subjects demonstrated while grasping 98 objects were photographed, analysed and compared.Fourteen types were identified as following: 1) Power grip-Standard type, 2) Power grip-Hook type, 3) Power grip-Index finger extension type, 4) Power grip-Distal type, 5) Power grip-Extension type, 6) Lateral grip, 7) Tripod grip-type I, 8) Tripod grip-type II, 9) Tripod grip-type III, 10) Parallel mild-flexion grip, 11) Tip grip (Tip prehension), 12) Surrounding mild-flexion grip, 13) Parallel extension grip, 14) Adduction grip.Eighty-six percent of the observed prehension could be fitted into one of these types and the rest into intermediate or combined ones.In all seven subjects, thirty-one of ninety-eight objects were grasped with identical patterns and the rest with two or more specific ones.