Identification of Sex from Metacarpals: Effect of Side Asymmetry

Abstract

This study tests the effect of bilateral asymmetry on the success rate of correct prediction of sex based on osteometric dimensions of the second metacarpal, using a method proposed by Scheuer and Elkington. A total of 351 bones from 179 individuals (47 documented as to age and sex), including 172 pairs, obtained from a 19th century cemetery were used to test the null hypothesis of no effect. A high success rate (>90%) for correct identification was found for males irrespective of side, although the larger right second metacarpal was a significantly better predictor. Conversely, there was a much lower success rate for females irrespective of side (<65%), although the smaller left metacarpal tended to give better results. The high success rate for males and low rate for females likely reflects the greater skeletal robustness of this historic sample relative to modern individuals. It is concluded that side asymmetry can have a significant effect on predictive efficiency for the Scheuer and Elkington model. As well, it is questionable whether the technique should be applied to non-industrial, that is, more skeletally robust, populations.

Population variation in second metacarpal sexual size dimorphism

“…An advantage of exploring dimorphism in second metacarpal morphology in such disparate samples is the obvious and intimate association of hand anatomy to the technological manipulation of the environment expressed in sex-specific activities mediating local (re)modeling of skeletal size and shape. While sex differences in metacarpal morphology have been studied from the point of view of basic skeletal biology (Garn et al, 1972;Plato and Purifoy, 1982;Fox et al, 1995;Lazenby, 1998a), growth and development (Smithgall et al, 1966;Himes and Malina, 1977;Kusec et al, 1988), aging (van Hemert et al, 1990Kimura, 1995;Mays, 2000), and forensic identification (Meadows and Jantz, 1992;Scheuer and Elkington, 1993;Lazenby, 1994;Falsetti, 1995;Smith, 1996), relatively few studies have examined behavioral correlates of such dimorphism, beyond questions of sex-differences in patterns of lateral hand dominance (Plato et al, 1984;Roy et al, 1994). A previous comparison of Euro-Canadian and Inuit samples demonstrated significant differences in aspects of Inuit metacarpal osteometry consistent with thermoregulatory adaptation vis-à -vis Allen's rule (Lazenby and Smashnuk, 1999), indicating a selective component.…”

Sex determination from hand dimensions for forensic identification

“…7,11 Then, it is recognized that anthropometric measurements of the hand has been very useful tool in sexual dimorphism detection. [12][13][14][15][16] This is also shown with the discriminant function equation that hand bone length measurements have been sexually dimorphic 17,18 Literature review suggests that sex can be determined with metacarpals length, 19,20 with first proximal phalanx 21 , with measurements and foot index. 22,24 Extensive work has been done with finger length ratios.…”

Sex determination using proximal hand phalanges

“…The ML of the proximal phalanx of the 1st and the 4th ray proved also important, contrary to the case of the equivalent proximal left phalanges. When ML and the widths at the head were tested separately (functions 17,18), only the variables of the 1st and the 4th ray entered in the analysis. However, in functions 19 and 20, only measurements of the 2nd finger did not contribute to the analysis.…”

“…In literature, there have been numerous studies on sex determination using hand bones, such as the metacarpals [3,[18][19][20]. Concerning proximal hand phalanges, however, there are few researches investigating sex determination.…”