We present a skeletal linked model of the human hand that has natural motion. We show how this can be achieved by introducing a new biology-based joint axis that simulates natural joint motion and a set of constraints that reduce an estimated 150 possible motions to twelve. The model is based on observation and literature. To facilitate testing and evaluation, we present a simple low polygon count skin that can stretch and bulge. To evaluate we first introduce a hand-motion taxonomy in a two-dimensional parameter space based on tasks that are evolutionary linked to the environment. Second, we discuss and test the model. The appendix shows motion sequences of the model and the real hand. Animations can be fetched from our website