title: Cross-sectional structural variation relative to midshaft along hominine diaphyses. I. The forelimb.
abstract: OBJECTIVE
  Analyses of hominine forelimb diaphyseal structure typically employ sections located at midshaft. This study addresses three questions. First, how accurately must midshaft be defined to yield comparable data? Second, does variation in midshaft location due to alternative definitions fall within error ranges such that data gathered using different length measurements are comparable? Third, do error ranges and length metric effects differ between elements or taxa such that certain bones or species are more prone to issues of comparability?
  
  
  METHODS
  Humeri, radii, and ulnae of Homo, Pan, and Gorilla were CT-scanned at full length and error ranges for three structural parameters (CSA, J, Imax /Imin ) were calculated around midshafts.
  
  
  RESULTS
  Distances proximally and distally from midshaft where structural values become significantly different from midshaft values vary between elements, taxa, and structural parameters. Error ranges are largest for the humerus and smallest for the ulna. Among taxa, error ranges for gorillas are largest and those for humans are smallest. Among structural parameters, error ranges depend on element and taxon such that no parameter consistently exhibits larger or smaller error ranges across all bones or species. Variation in midshaft locations originating from different length definitions is small and falls within error ranges defined by maximum length across all elements and taxa.
  
  
  CONCLUSIONS
  Including fragmentary specimens for which midshaft location is uncertain in comparisons of forelimb diaphyseal structure requires evaluation on a case-by-case basis, with consideration to element, taxon, and structural traits of interest. However, midshaft data for all three structural parameters considered here that are recorded using different length measurements can be reasonably compared.
authors.affiliation: Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, NY, 11794.
authors.forename: Carrie S
authors.initials: CS
authors.lastname: Mongle
authors.affiliation: Department of Anthropology, Stony Brook University, Stony Brook, NY, 11794.
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Wallace
authors.affiliation: Department of Anthropology, Stony Brook University, Stony Brook, NY, 11794.|Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, 11794.
authors.forename: Frederick E
authors.initials: FE
authors.lastname: Grine
mesh_terms: D000717:Anatomy, Comparative; D000818:Animals; D050280:Arm Bones / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D018483:Diaphyses / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D005260:Female; D015186:Hominidae / Q000033:anatomy & histology*; D008297:Male; D014057:Tomography, X-Ray Computed
keywords: ape; chimpanzee; cortical bone; cross-sectional geometry; gorilla; humerus; radius; ulna; upper limb