Key points are not available for this paper at this time.
In the normal hand five linked metacarpophalangeal units radiate from a fixed semi-circular transverse carpal arch. Their longitudinal and transverse convergent and divergent flexion-extension paths execute a series of equiangular curves which adapt the thumb and fingers to innumerable tasks. Furthermore, refined independent movement and tactile sensibility reside in each of the digits, notably in the opposable thumb where great mobility and power subserve the fingers for pinch and grasp.
J. William Littler (Fri,) studied this question.