The interpretation of the evolution of human manipulative and locomotor behavior from hominid fossil remains during the Pleistocene requires a clear distinction between changes in relative musculo-skeletal massiveness indicating different levels of activity (robusticity) and alterations in form implying contrasting patterns or frequencies of behavior. A review of ongoing research on Neandertal appendicular morphology with respect to the scapulo-humeral articulation, the pollical and mid-carpal carpo-metacarpal articulations, proximal femoral trabecular orientation, femoral diaphyseal cross-sectional geometry, and proximal pedal phalangeal diaphyseal proportions illustrate the nature of the problems associated with making distinctions between robusticity and shape in fossil hominid remains. Nonetheless, it is apparent that differences in shape, in addition to contrasts in robusticity, exist between the Neandertals and modern humans.