Non-dietary Marks in the Anterior Dentition of the Krapina Neanderthals

A sample of 82 anterior teeth from Krapina (Croatia) was studied using a light binocular microscope and a scanning electron microscope to document the presence of non-dietary dental scratches. The patterns of distribution, location and orientation of these marks suggest two different aetiologies: scratches on the labial-occlusal enamel border appear to be related to the action of clenching abrasive materials between teeth, while the scratches primarily in the centre of the labial face correspond to cutmarks as described by other researchers. These scratches may have been produced when flake tools involved in processing materials held between the anterior teeth came into contact with the labial enamel face. Alternatively, they may simply reflect some consistent operation which pulled hard objects across the labial surfaces of the anterior teeth. In either case, the marks on the central face of the labial surface provide evidence for manual dexterity in the Neanderthals. Of the seven Krapina individuals which show a predominant pattern, one shows a pattern of left oblique marks, while six provide evidence of right-handedness. Coupled with other Neanderthal or Upper Pleistocene individuals with these patterns, right-handedness is the dominant pattern in 90 per cent of the documented cases. One complicating factor in the analysis of these scratches in the Krapina hominids is that marks of a similar morphology are found in several anterior teeth of Ursus spelaeus from the site. While resembling the marks on the hominid incisors, the scratches on the bears lack a dominant orientation on the labial face and appear to be more variable in their widths. Despite the occurrence of some similarities in the enamel scratches between ursids and hominids at Krapina, the study of anterior dental marks provides information about manipulative activities which are unique to ancient humans. © 1997 by John Wiley & Sons, Ltd. Int. J. Osteoarchaeol., 7 : 133–149 (1997) No. of Figures: 9. No. of Tables: 5. No. of References: 34.     

Incisor labial surface wear striations in modern humans and their implications for handedness in Middle and Late Pleistocene hominids

Over the past four decades several workers have argued that the orientations of striations on the labial surfaces of the front teeth of Middle and Late Pleistocene fossils attributed to Neanderthals and antecedent archaic hominids can tell us something about handedness. These researchers have suggested that such scratches result from stone tools scraping across the incisors during ‘stuff‐and‐cut’ behaviours, and that they reflect directions of hand movements and handedness. In this study, we examine comparable wear features on the incisors of anatomically modern humans to determine whether striation angle may reflect handedness. The teeth from 66 individuals representing four groups with known differences in subsistence practices (Aleut, Arikara, Illinois Bluff, and Puye) were examined. Photomicrographs were made of the maxillary central incisor labial surfaces of all individuals at 56× magnification. These photomicrographs were scanned to image files, and orientations of all visible wear striations were measured using a semi‐automated image analysis procedure. Approximately three‐quarters of all labial surfaces showed a preferred striation orientation. Of those, most had preferred apico‐cervical or vertical striation orientations, independent of cultural affiliation. Few showed the tendency toward diagonally‐oriented scratches expected if handedness is related to scratch orientation. We found no evidence for ‘stuff‐and‐cut’ striations, despite the fact that at least one of the groups studied—the Aleut—are documented to have used this behaviour. In sum, there is evidently no relationship between striation orientation and handedness in the groups studied. It is, therefore, unlikely that labial scratch orientation in Middle and Late Pleistocene hominids reflects handedness if they used their front teeth in a manner comparable to that of any of the anatomically modern groups considered here. Copyright © 1999 John Wiley & Sons, Ltd.     

Assessment of Musculoskeletal Stress Marker Development in the Hand

The analysis of musculoskeletal stress marker (MSM) development is a commonly employed tool in osteological surveys and is used to infer patterns of occupational activity and societal organisation in archaeological populations. Although the majority of research into upper limb MSMs has focused on the bones of the arm, the bones of the hand have been conspicuous by their absence. This is likely to be due to methodological issues surrounding the study of hand bones and a presumed lack of variation in MSM development in this area. To date, there have been no systematic studies investigating the presence and variation in MSM morphology for the muscles of the human hand. To address this issue, a presence/absence scoring system was developed for twelve sites of muscle origin and insertion in the metacarpals and phalanges, which was used to determine bilateral asymmetry in the hands of 31 individuals from the Naval Hospital Cemetery site in Greenwich, London. Analysis found observable variation in MSM development between and within the hands, which could be used to determine patterns of asymmetry within the sample. Comparisons with MSM scores from the humeri of these individuals indicate a differentiation in MSM development and asymmetry between these anatomical regions. Levels of asymmetry in the hands and humeri were generally low, with only the dorsal interossei displaying statistically significant asymmetry. Subsequent upper limb MSM research will benefit from the inclusion of data from the hands. These results do not support the continued use of the humerus as a proxy for MSM expression across the upper limb as a whole and suggest that important information regarding behavioural asymmetry in the hands is being lost because of the continual exclusion of this anatomical unit from MSM research. Copyright © 2011 John Wiley & Sons, Ltd.     

Handedness and directional asymmetry in the long bones of the human upper limb

The long bones of the human upper limb usually show lateral asymmetries of length. This pattern can be attributed either to the mechanical consequences of handedness bias or to genetic or hormonal factors acting directly on longitudinal bone growth. Length data was obtained from the long bones of the upper limbs of a large skeletal assemblage from Wharram Percy, Yorkshire (England), predominantly deriving from the 11th-16th centuries A.D. The Wharram Percy adult skeletons had a population distribution of lateral asymmetries of length in the humerus and in the humerus-plus-radius (a proxy arm length index) which closely parallels the pattern of behavioural handedness found in modern populations. This pattern was developing in the skeletons from the infant and juvenile age ranges, but was absent in the neonates (of whom 12 out of 14 had longer left humeri). We argue that this supports the environmental hypothesis that the ontogeny of long bone length asymmetry is consequent to the earlier development of lateral bias in mechanical loading of the upper limbs.     

Directional asymmetry in the human clavicle

The human right clavicle tends to be shorter than the left. A range of possible explanations can be advanced to account for this asymmetry. In the present work, clavicular morphology was studied in a medieval skeletal assemblage from Wharram Percy, England, with the aim of evaluating these competing explanations. At Wharram Percy, as anticipated, the right clavicle tended to be shorter. Patterns of asymmetry in curvature, robusticity, vascularization, and in the morphology of ligament and muscle attachment sites were also studied. The patterning in these data at Wharram Percy is consistent with inhibition of longitudinal growth of the clavicle on the dominant side due to lateral bias in mechanical loading, particularly in axial compression. Copyright © 1999 John Wiley & Sons, Ltd.     

Directional bilateral asymmetry in human sacral morphology

Directional bilateral asymmetries in human gross skeletal morphology are largely attributable to differential mechanical loading from handedness during endochondral bone growth. While much has been done in the way of identifying directional asymmetries of the upper limb in relation to handedness, comparatively little research has focused on asymmetry in the lower body. The present paper analyses asymmetry in the human sacrum in a sample of 238 modern individuals. Measurements of right and left sides of the lateral and posterior breadths of the alae and the maximum height of the auricular surface were used. Asymmetry was calculated as: [(left side − right side) ÷ right side] * 100. Directional asymmetry was identified using a one‐sample t‐test against a hypothesized mean of zero. Significant directional asymmetry (P < 0.05) was found in all three dimensions. The pattern of asymmetry is consistent with models describing the influence of right‐handedness on the lower body, which predicts that left side dimensions will be larger. Copyright © 2002 John Wiley & Sons, Ltd.