Who’s Afraid of the Big Bad Wolff?: ‘‘Wolff’s Law’’ and Bone Functional Adaptation

Abstract

ABSTRACT ‘‘Wolff ’s law’’ is a concept that has sometimes
been misrepresented, and frequently misunderstood,
in the anthropological literature. Although it was
originally formulated in a strict mathematical sense that
has since been discredited, the more general concept of
‘‘bone functional adaptation’’ to mechanical loading (a
designation that should probably replace ‘‘Wolff ’s law’’) is
supported by much experimental and observational data.
Objections raised to earlier studies of bone functional
adaptation have largely been addressed by more recent
and better-controlled studies. While the bone morphological
response to mechanical strains is reduced in adults
relative to juveniles, claims that adult morphology
re.ects only juvenile loadings are greatly exaggerated.
Similarly, while there are important genetic in.uences
on bone development and on the nature of bone’s
response to mechanical loading, variations in loadings
themselves are equally if not more important in determining
variations in morphology, especially in comparisons
between closely related individuals or species. The
correspondence between bone strain patterns and bone
structure is variable, depending on skeletal location and
the general mechanical environment (e.g., distal vs.
proximal limb elements, cursorial vs. noncursorial animals),
so that mechanical/behavioral inferences based on
structure alone should be limited to corresponding skeletal
regions and animals with similar basic mechanical
designs. Within such comparisons, traditional geometric
parameters (such as second moments of area and section
moduli) still give the best available estimates of in vivo
mechanical competence. Thus, when employed with
appropriate caution, these features may be used to
reconstruct mechanical loadings and behavioral differences
within and between past populations. Am J Phys
Anthropol 129:484–498, 2006. VVC 2006 Wiley-Liss, Inc.