The three partial skeletons from Sunghir retain substantial portions of their shoulder and arm remains, from the proximal clavicle to the distal radius and ulna. The scapulae, as with most of those from the Pleistocene, retain principally the spine, the glenoid area, the coracoid process, and the axillary border. The left forearm of Sunghir 2 is absent (as is his left hand), and the left humerus consists of a diaphyseal section without the metaphyses and a partial proximal epiphysis. It is nonetheless possible to assess both overall upper limb proportions (chapter 11) and a number of aspects that relate to upper limb asymmetry, clavicle and scapular morphology, glenohumeral proportions, diaphyseal robustness, cubital articulations, and reflections of pronation-supination hypertrophy for all three of them. Although humans are considered to be bilaterally symmetrical in their limbs, there are small degrees of asymmetry in most limb bones. These asymmetries are frequently exaggerated in the human upper limb, given our handedness and the subsequent preference for use of the dominant arm in more mechanically demanding activities (Raymond and Pontier 2004). In general, the level of asymmetry in the dimensions of epiphyses, and especially of articulations, is modest. However, substantial asymmetry in measures of upper limb diaphyses (particularly of the humerus) have been documented in samples of recent humans (e.g., Ruff and Jones 1981; Fresia et al. 1990; Trinkaus et al. 1994; Roy et al. 1994; Churchill 1994; Steele and Mays 1995; Sakaue 1997; Mays 2002; Auerbach and Ruff 2006; Cowgill 2008; Auerbach and Raxter 2008), as well as in a number of Late Pleistocene humans (e.g., Trinkaus et al. 1994; Churchill and Formicola 1997; Cowgill 2008; Shang and Trinkaus 2010; Cowgill et al. 2012b; Mednikova 2012; Volpato et al. 2012). Moreover, as is indicated by labial anterior dental striations and one individual’s forearm bones, such handedness extends back through the genus Homo (Weaver et al. 2001; Frayer et al. 2012).
Trade-Offs in Relative Limb Length among Peruvian Children: Extending the Thrifty Phenotype Hypothesis to Limb Proportions
