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Going to extremities: is variation in human limb length and proportions a paradox?
Author(s) -
Auerbach Benjamin Miller
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.61.3
Subject(s) - allometry , lower limb , torso , variation (astronomy) , thermoregulation , anatomy , scaling , biology , body segment , variance (accounting) , mathematics , ecology , medicine , geometry , physical medicine and rehabilitation , physics , surgery , accounting , astrophysics , business
Group comparisons indicate thermoregulation, nutrition, and locomotor efficiency as factors affecting human limb length and proportional variation. Humans from warmer climates have longer limbs relative to torso length and higher intralimb intermembral indices, likely reflecting thermoregulatory necessity; distal segments have higher surface area‐to‐mass relative than proximal segments, and longer limbs dissipate more heat. Despite this pattern, paradoxically, limb proportions and limb lengths were shown to not correlate in previous research. Subsequent analysis concluded that limb proportions are adaptively constrained and do not closely reflect limb elongation. Using a global sample of 3680 pre‐industrial skeletons, this study reexamines this incongruity. Coefficients of variation show that variance in proximal relative to distal elements is not universal among all human groups, though distal elements generally have greater variance. Scaling analyses indicate longer limbs have disproportionately longer distal elements and disproportionately shorter proximal elements, following thermoregulatory expectations. Different allometric relationships for proximate and distal elements may obscure these patterns when their lengths are expressed as ratios. Variation in these patterns among groups, and the effects of mechanics and nutrition, are further considered.