Biology Reference
In-Depth Information
CHAPTER
14
Functional Morphology and
Medical Imaging
Megan K. Moore
INTRODUCTION
This chapter explores theoretical and methodological considerations of research in func-
tional morphology and bone biomechanics.
Washburn (1951)
proposed that the “New Phys-
ical Anthropology”
1
focus more on questions of functional morphology and anatomy as
opposed to questions of simple typological classification. The goal of this chapter is to
promote that same vision by providing the young researcher with the necessary tool kit
for functional morphology research. The chapter begins with a brief overview of the proper-
ties of skeletal tissues, bone biomechanics, and the functional adaptation of the skeleton.
Functional morphology research can be broken down into four general categories: (1)
cross-sectional geometry; (2) joint form and pathology; (3) trabecular architecture; and (4)
histology (
Pearson and Lieberman, 2004
). Each category studies different aspects of bone
shape, either at the macroscopic or at the microscopic level. This chapter will focus on the first
two categories relating to macrostructure. Trammell and Kroman explore bone microstruc-
ture in greater detail in the chapter on histology in this volume (Chapter 13).
Many different methods have been used to analyze bone macrostructure. Cross-sectional
shape can reveal the bone's ability to resist a variety of forces. A bone's shape is the result of
a combination of both intrinsic and extrinsic variables. Intrinsic or systemic factors act from
within the body, such as genetic constraints and hormone levels. Extrinsic factors acting on
the skeleton can be due to the environmental influence of nutrition or to the biomechanical
influence of different forces acting on the skeleton, such as locomotion and gravity. For
example, the neck of the femur is nearly vertical in infancy and only becomes angled as
we begin to walk, the result of extrinsic biomechanical variables (
Tardieu, 1999
).
A variety of different research methods have been developed and implemented to try to
understand the functional adaptations of the skeleton. While a two-dimensional radiograph
can reveal the internal structure of a bone, it can only provide a rough approximation of the
1
All bolded terms are defined in the glossary at the end of this volume.
