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Does Human Sexual Dimorphism Influence Fracture Frequency, Types and Distribution?

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Does Human Sexual Dimorphism Influence Fracture Frequency, Types and Distribution? AnthropologicAl review • Vol. 74, 13–23 (2011) Does human sexual dimorphism influence fracture frequency, types and distribution? Jonna Nielsen ADBOU, Forensic Institute, University of Southern Denmark, Lucernemarken 20, Dk-5260 Odense, Denmark; E-mail [email protected] ABSTRACT This study explores the hypothesis that the pattern of gender inequality in a community influences the frequency, patterns and distribution of fractures. As it is not possible to read gender relations from skeletons, it is – following several research results – assumed that the level of gender inequality is reflected in sexual dimorphism. Thus the study design consists in correlating a measure of sexual dimorphism with measures of frequencies, patterns and distribution of skeletal trauma between the two sexes. Nearly two hundreds individuals from two medieval Danish cemeteries have been examined (43 females/48 males from Jutland and 46 females/49 males from Funen). Sexual dimorphism was assessed by means of measurements on the pelvis and, in accordance with conventional wisdom, the level of sexual dimorphism was found to be lower in the Funen than in the Jutland sample. The fracture frequencies, patterns and distribution were estimated for the two skeletal samples. No significant difference between the fracture frequencies or types on the two sites was found, but the distribution of fractures between the sexes in Ribe was found to be significantly different. The study indicates a level of relationship between human sexual dimorphism, gender roles, and the distribution of fractures between the sexes. Studies of larger samples will help clarify this. KEY WORDS: interpretation of injuries, gender roles, medieval Denmark Studies of old skeletal remains often in- them having been controlled by beating by dicate a relatively high fracture frequency their men and thus that these women were in ancient communities compared to more socially inferior to men. Consequently, the recent data, and this higher fracture fre- frequency of fractures contributes to the so- quency is assumed to have been more pro- ciological interpretation of women’s status nounced for women. Central to the inter- in historic and prehistoric communities. pretation of this difference seems to be an The incentive for embarking on this almost unanimous consensus to interpret study was to evaluate alternative expla- fractures seen in women as an indication of nations of fracture by testing the hypoth- Received 20 November 2010; accepted 8 July 2011 DOI: 10.2478/v10044-010-0002-3 © 2011 Polish Anthropological Society 14 J. Nielsen esis that the human sexual dimorphism higher human sexual dimorphism than the observed in a community correlates with skeletons from Funen. This theory was test- the distribution of fractures (work/accident ed and supported by another study carried as well as violence related) between the out alongside the present study. two sexes, whereas fracture frequency and types could be influenced by other factors. Materials This study correlates a measure of human sexual dimorphism with measures of fre- Skeletal remains and their dating quencies, types and the distribution of skel- etal traumas. Although the two osteologi- The skeletal remains from Funen used cal elements (human sexual dimorphism for this study came from excavations of and fractures) have been studied separately two adjoining cemeteries in central Odense. by various scholars [Smith & Jones 1910; The excavations, initiated by Odense City Nielsen 1970; McWhirr et al. 1982; İşcan & Museum, were under the supervision of Miller-Shaivitz 1984; Rösing 1990; İşcan Jacob Tue Christensen. The main part of et al. 1994; Smith 1996; Steyn & İşcan the material for this study came from the 1997; González-Reimers et al. 2000; Judd excavation OBM no. 9784, which was con- 2002a,b, 2004, 2006, 2008; Rich et al. ducted in March-May 1998. This excava- 2005; Šlaus & Tomičic 2005], the correla- tion provided skeletal material from a total tion between the two types of data has, to of 165 graves. The subsequent excavation the best of my knowledge, never been stud- OBM no. 9785 provided skeletal material ied before, and has a potential which needs from 170 additional graves. to be more widely acknowledged and ex- The skeletal remains from Jutland were plored. It is important to note that this study unearthed in connection with an excava- is focused on patterns of daily activity and tion in Ribe. The excavation ASR no. 1015, the distribution of fractures between the headed by Jacob Kieffer-Olsen, was con- two sexes, and not so much on individual ducted in 1993. In total, 592 graves were cases and distribution of fractures between excavated. social classes. The dating of skeletal material from In order to carry out this study, it was es- Odense was based on the observed arm po- sential to have material from two locations, sition “a, b, c or d” (see Fig. 1) in the grave one with a documented high degree of hu- according to the method described by Jacob man sexual dimorphism and one with a low Kieffer-Olsen [Christensen 1999]. This degree. It was necessary that the material method of dating, supported by archaeolog- came from a compatible time period, and ical and written evidence, indicated that the the communities presented a well docu- vast majority of the skeletons from Odense mented and compatible socio-economic could be ascribed to the Danish medieval structure. The Danish medieval skeletons period from 1086 AD to 1542 AD [Chris- stored at ADBOU at the University of tensen 1999]. Assuming that Jacob Kieffer- Southern Denmark were found to be highly Olsen used the above-mentioned method suitable for this study. After years of study described by him in combination with the of the more than 12000 skeletons held here, archaeological and written evidence, the the staff had developed the theory that the skeleton remains from Ribe could be dated skeletons from Jutland presented a much from mid 1200 AD to 1400 AD. Human sexual dimorphism and fractures 15 1999: 86]. The skeletons came from the more prestigious locations in and just outside the church as well as from other sections of the cemeteries. Comparisons of the socio-economic structure, dating of the remains and age distribution (as will be seen later) seem to indicate a fairly high compatibility in the material from the two Fig. 1. Schematic drawing of arm positions locations. used in the Danish medieval period (“a” being the oldest, and “d” the youngest) [Christensen 1999, p. 89]. Methods Age and sex determination Socio-economic mix of skeletons As human sexual dimorphism was As studies such as those carried out by a central part of this study, it was decided Rösing [1990], Judd [2006] and others to use only skeletons from adults for this indicate that social class and occupation investigation; thus individuals where SOS (subsistence related activities) will influ- (spheno-occipital synchondrosis) had not ence fracture frequencies and patterns, yet fused and where the epiphysis lines in- it was essential to ascertain that the two dicated an age below 16 [Bass 2005] were sites provided material from compatible excluded, as were very fragmented skel- societies with compatible social mix. Both etons. A similar method was used by Judd written and archaeological sources give us [2002a, 2004] when examining the skeletal a very clear picture of the medieval period remains from the Nubian site Kerma. in Ribe and Odense. Both cities functioned Sex determination was made based on as important centres for trade and craft examination of the skull, the pelvis and [Nielsen 1985, Christensen 1988]. Odense the post-cranial skeleton [Mays 1998, was right in the centre of the trade routes Bass 2005]. On the skull the following linking the western and the southern parts 5 points were assessed: absence or pres- of Denmark, and Ribe controlled the con- ence of a brow ridge (glabella), size of the nection to the European market. Hence, mastoid process, size of the muscular at- both cities were major urban locations in tachment in the neck, the thickness of the medieval Denmark, and their inhabitants eye cavity rim (orbital rim) and the height engaged in identical occupations (e.g., and angle of the lower jaw (mandible). The merchants, craftsmen, dignitaries, clergy- pelvis was assumed to provide the most ac- men). So, all in all, the material from the curate indication of the individual’s sex. In two locations seems to indicate a fairly the pelvis, sex indication was determined compatible mix in the socio-economic on the form of the pubic bone (pubis), the structure of the societies from which the angle of the bones (ischium) leading to the skeletons came, and thus in the two sam- pubic bone, and the general “openness” of ples. Studies of the excavation reports, in the pelvis (providing a birth canal). The particular the position of the graves, fur- overall size and robustness of other bones ther support this assumption [Christensen of the skeleton (the post-cranial bones) 16 J. Nielsen were also considered. After the overall as- mas were entered into an excel spreadsheet sessment described above, each skeleton to ensure optimal registration of all fractures was given an individual score ranging from and to facilitate further statistical evalua- 1 to 7, 1 being evidently male, 4 denoting tions. On the spreadsheet were entered the that sex could not be determined, and 7 be- grave number, sex and age of the individual, ing evidently female. The scores 3 and 5 the degree of preservation of the skeleton, were given to individuals with low sexually as well as the specific bones fractured, side dimorphic characteristics. indication (right/left part of the body), and Ages were determined from multiple probable cause of the fracture (impact of osteological age indicators as suggested high- or low-energy). The statistical analysis by leading scholars (Calibrated Expert In- was performed with the computer program ference – J.L.
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