TY - JOUR
T1 - Body size, body shape, and long bone strength in modern humans
AU - Ruff, Christopher B.
N1 - Funding Information:
I would like to thank Dr Sam Luboga, the Government of Kenya and the Governors of the National Museums of Kenya for permission to study the East African samples, the Harvard Peabody Museum for permission to study the Pecos Pueblo sample, Dr Robert Tague for providing bi-iliac breadths for the Pecos sample, and four reviewers for their constructive comments. This work was supported in part by NSF grant #BNS-8919155.
PY - 2000/2
Y1 - 2000/2
N2 - To identify behaviorally significant differences in bone structure it is first necessary to control for the effects of body size and body shape. Here the scaling of cross-sectional geometric properties of long bone diaphyses with different 'size' measures (bone length, body mass, and the product of bone length and body mass) are compared in two modern human populations with very different body proportions: Pecos Pueblo Amerindians and East Africans. All five major long bones (excluding the fibula) were examined. Mechanical predictions are that cortical area (axial strength) should scale with body mass, while section modulus (bending/torsional strength) should scale with the product of body mass and moment arm length. These predictions are borne out for section moduli, when moment arm length is taken to be proportional to bone length, except in the proximal femoral diaphysis, where moment arm length is proportional to mediolateral body breadth (as would be expected given the predominance of M-L bending loads in this region). Mechanical scaling of long bone bending/torsional strength is similar in the upper and lower limbs despite the fact that the upper limb is not weight-bearing. Results for cortical area are more variable, possibly due to a less direct dependence on mechanical factors. Use of unadjusted bone length alone as a 'size' measure produces misleading results when body shape varies significantly, as is the case between many modern and fossil hominid samples. In such cases a correction factor for body shape should be incorporated into any 'size' standardization.
AB - To identify behaviorally significant differences in bone structure it is first necessary to control for the effects of body size and body shape. Here the scaling of cross-sectional geometric properties of long bone diaphyses with different 'size' measures (bone length, body mass, and the product of bone length and body mass) are compared in two modern human populations with very different body proportions: Pecos Pueblo Amerindians and East Africans. All five major long bones (excluding the fibula) were examined. Mechanical predictions are that cortical area (axial strength) should scale with body mass, while section modulus (bending/torsional strength) should scale with the product of body mass and moment arm length. These predictions are borne out for section moduli, when moment arm length is taken to be proportional to bone length, except in the proximal femoral diaphysis, where moment arm length is proportional to mediolateral body breadth (as would be expected given the predominance of M-L bending loads in this region). Mechanical scaling of long bone bending/torsional strength is similar in the upper and lower limbs despite the fact that the upper limb is not weight-bearing. Results for cortical area are more variable, possibly due to a less direct dependence on mechanical factors. Use of unadjusted bone length alone as a 'size' measure produces misleading results when body shape varies significantly, as is the case between many modern and fossil hominid samples. In such cases a correction factor for body shape should be incorporated into any 'size' standardization.
KW - Allometric scaling
KW - Biomechanics
KW - Body shape
KW - Long bones
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U2 - 10.1006/jhev.1999.0322
DO - 10.1006/jhev.1999.0322
M3 - Article
C2 - 10656779
AN - SCOPUS:0034071062
SN - 0047-2484
VL - 38
SP - 269
EP - 290
JO - Journal of Human Evolution
JF - Journal of Human Evolution
IS - 2
ER -