Biomechanics and BoneStress in Anthr opolog yMichelle Beckhorn; Session 1; 7 May 2012; Cave
Biomechanics Application of mechanical principles to biological systems Used in anthropology to explain skeletal variation among populations past and present Can be used to understand cultural practices such as throwing spears, heavy workloads, spatial movement, knapping, etc.
Methods ofUnderstandingBiomechanics Wolff’s law states simply that mechanical loading influences bone structure Bone function adaptation states that mechanical deformation or strain of bone tissue occurs under mechanical loading. Body Size Muscle Activity Example: robusticity of the long bone diaphysis between modern populations and past populations
Variations to Consider Diet Disease Age at death Genetics Hormones Gender Size
Aspects to consider invariations Because of the high variations within populations, it is most accurate to compare sides within an individual than one individual to another. The dominant side will exhibit bone stress marks resulting from mechanical load or movement. Within a population, if there are many individuals with such marks, the cultural trend can be better assessed Cold environments can accelerate bone stress due to blood vessel constriction Age at which mechanical strain begins affects the severity of the bone stress.
Early Thule of the HudsonBay Supports evidence of umiaks Kayaker’s Clavicle and humor stress strong to heavy Gender role differences Late start Hunting changes from whaling to seal 90 percent left handedness
Evolutionary Trends in Bone Robusticity Over the past two million years bone robusticity has decreased by 30% Resulting from the decrease in walking long distances, mechanical load and introduction of agriculture and industry. Increase of potential osteoporosis Physical environment and effects of cultural practices
Conclusion Taking into consideration the variations listed, we can understand how culture can effect the amount of mechanical loads which influences bone stress such as robusticity on the long bone. Archaeologists can use bone stress marks to understand evolutionary and cultural trends of populations past and present.
References Hawkey, Diane E., Charles F. Merbs. Activity-induced musculoskeletal stress markers (MSM) and subsistence strategy changes among ancient Hudson Bay Eskimos. International Journal of Osteoarchaeology. Volume 5, Issue 4, pages 324–338, December 1995. M. ANNE KATZENBERG, Shelly Saunders. Biological Anthropology of the Human Skeleton. John Wiley and Sons Inc. Hoboken, NJ. 2008