Covariation of proximal finger and toe phalanges in Homo sapiens: A novel approach to assess covariation of serially corresponding structures.

We speculate that the results are possibly the evolutionary consequence of differential selection pressure on the big toe relative to the other toes related to the rise of bipedalism, which is proposed to have emerged very early in the hominin clade. In contrast, thumb morphology and its precision grip never ceased undergoing changes, suggesting less acute selection pressures related to the evolution of the precision grip.