Biology Reference
In-Depth Information
functional strength of the bone. Thus, some early research in functional morphology relied
on the destructive analyses of cutting transverse sections of the long bone shafts to deter-
mine the shape and surface area of the cortical bone cross-section (
Burr and Piotrowski,
1982; Harrington et al., 1993
). More recent studies take advantage of medical imaging
modalities, which are relatively nondestructive for skeletal samples and can provide
three-dimensional digital imaging of the internal and external structure, and the material
properties of bone density (one measure of bone strength) (
Groll et al., 1999; O'Neill and
Ruff, 2004; Stojanowski and Buikstra, 2005; Gu et al., 2008; Saeed et al., 2009; Sparacello and
Pearson, 2010; Hind et al., 2011; Moore and Schaefer, 2011; Samelson et al., 2012
). As medical
imaging technologies become less expensive, nondestructive methods are now available to
the biological anthropologist to investigate questions of biocultural influences on bone
strength and functional adaptation.
The New Physical Anthropology
In 1951, Sherwood Washburn called on physical anthropologists to rethink their research
questions (
Washburn, 1951
). He criticized the discipline for emphasizing data collection of
biological traits, only to use them to classify populations, what he called a typological
approach. Washburn considered this research to have a limited scope with little theoretical
development. He proposed that the “New Physical Anthropology” take an interest in under-
standing human variation and the process of evolution; essentially a “return to Darwinism”
(
Washburn, 1951
). Instead of simply recording a trait, he emphasized the need to understand
why the trait is there in the first place, with an emphasis on functional morphology and
anatomy. More than 50 years later, Armelagos and Van Gerven (2003) reevaluated the disci-
pline to assess whether we are now successfully addressing Washburn's concerns. They
concluded that there is some progress, but it has been slow in terms of the number of studies
addressing functional anatomy versus the number that continue to do research using a more
typological approach (Armelagos and Van Gerven, 2003). Stojanowski and Buikstra (2004)
published a rejoinder to this critique, disagreeing with the conclusion of the former publica-
tion about typological studies. Regardless, a functional morphology approach provides
a more comprehensive understanding of the human skeletal form. This chapter therefore
introduces some of the theory behind functional morphology with advice on how to conduct
your own study.
BASIC BONE BIOLOGY
The skeleton appears to be a stable structure, yet the living skeleton is a dynamic system,
constantly remodeling in response to both extrinsic mechanical forces and intrinsic metabolic
processes. For example, moderate exercise is enough to increase bone mass (Nilsson and
Westlin, 1971). Bone acts as a reservoir of calcium to maintain the normal function of the
body and muscles. Bone tissue is made up of three different types of cells that maintain
bone homeostasis, which are the osteoclasts, osteoblasts, and osteocytes. Osteoclasts are
cells that function to resorb existing bone in order to release minerals, remove organic waste,
and respond to injury, while osteoblasts synthesize new bone matrix or osteoid (the
