Hip bone trabecular architecture shows uniquely distinctive locomotor behaviour in South African australopithecines

ArticleinJournal of Human Evolution 36(2):211-32 · March 1999with18 Reads
DOI: 10.1006/jhev.1998.0267 · Source: PubMed
Abstract
Cancellous bone retains structural and behavioural properties which are time and strain-rate dependent. As the orientation of the trabeculae (trajectories) follows the direction of the principal strains imposed by daily loadings, habitual postural and locomotor behaviours are responsible for a variety of trabecular architectures and site-specific textural arrangements of the pelvic cancellous network. With respect to the great ape condition, the human trabecular pattern is characterized by a distinctive ilioischial bundle, an undivided sacropubic bundle, and a full diagonal crossing (approximately 100 degrees) over the acetabulum between the ilioischial and the sacropubic bundles. Advanced digital image processing (DIP) of hip bone radiographs has revealed that adolescent and adult South African australopithecines retained an incompletely developed human-like trabecular pattern associated with gait-related features that are unique among the extant primates.
    • "The pelvis is a critical link in the hindlimb locomotor system, as the muscles of propulsion attach to it and forces from the limb are transmitted through it to the trunk. In biological anthropology, the pelvis has been at the center of a critical debate regarding the evolution of bipedal behaviors in fossil hominins and how the pelvis adapted to this novel form of primate locomotion (Reynolds, 1931; Dart, 1949; Le Gros Clark, 1955; Day, 1973; Lovejoy et al. 1973 Lovejoy et al. , 2009 Brain et al. 1974; McHenry, 1975; Ashton et al. 1981; Berge, 1984; Rak & Arensburg, 1987; Rak, 1991; Fleagle & Anapol, 1992; Rosenberg, 1992; Ruff, 1995 Ruff, , 2010 Macchiarelli et al. 1999; Marchal, 2000; Haeusler, 2002; Lovejoy, 2005; Weaver & Hublin, 2009; Kibii et al. 2011). While many studies have correlated pelvic anatomy with locomotor behavior (Ashton et al. 1981; Berge, 1984; Ward, 1991; Fleagle & Anapol, 1992; Anemone, 1993; MacLatchy & Bossert, 1996; MacLatchy, 1998), a lack of understanding of pelvic biomechanics (i.e. "
    [Show abstract] [Hide abstract] ABSTRACT: The pelvis is a critical link in the hindlimb locomotor system and has a central role in resisting loads associated with locomotion, but our understanding of its structural biomechanics is quite limited. Empirical data on how the pelvis responds to the loads it encounters are important for understanding pelvic adaptation to locomotion, and for testing hypotheses regarding how the pelvis is adapted to its mechanical demands. This paper presents in vitro strain gauge data on a sample of monkey and ape cadaveric specimens (Macaca, Papio, Ateles, Hylobates), and assesses strain magnitudes and distributions through the bones of the pelvis: the ilium, ischium and pubis. Pelves were individually mounted in a materials testing system, loads were applied across three hindlimb angular positions, and strains were recorded from 18 locations on the pelvic girdle. Peak principal strains range from 2000 to 3000 με, similar to peak strains recorded from other mammals in vivo. Although previous work has suggested that the bones of the pelvis may act as bent beams, this study suggests that there are likely additional loading regimes superimposed on bending. Specifically, these data suggest that the ilium is loaded in axial compression and torsion, the ischium in torsion, the pubic rami in mediolateral bending, and the pubic symphysis is loaded in a combination of compression and torsion. Compressive strains dominate the pelves of all species representatives. Shear strains change with limb position; hip flexion at 45 ° induces smaller shear strains than mid-stance (90 °) or hip extension (105 °). The pelvic girdle is a complex structure that does not lend itself easily to modeling, but finite element analyses may prove useful to generate and refine hypotheses of pelvic biomechanics. © 2015 Anatomical Society.
    Full-text · Article · Apr 2015
    • "In response to the new biomechanical constraints imposed by the erect posture, the skeleton of our ancestors was adaptively modified over the course of evolution, optimizing the functional performances of the locomotor system. In the literature, human synapomorphies that could be functionally involved in bipedal gait and posture have been identified, including morphological traits of the hip (e.g., Zihlman and Hunter, 1972; Lovejoy et al., 1973; McHenry, 1975; Berge and Ponge, 1983; Stern and Susman, 1983; Tardieu, 1983 Tardieu, , 1999 Berge et al., 1984; Asfaw, 1985; Berge and Kazmierczak, 1986; Lovejoy, 1988 Lovejoy, , 2005a Abitbol, 1989 Abitbol, , 1995 Ruff, 1994 Ruff, , 1998 MacLatchy and Bossert, 1996; Macchiarelli et al., 1999; Marchal, 2000; Haüsler, 2002). The hip joint, a diarthrosis, which articulates the acetabular region with the proximal femur, occupies a central place in the locomotor skeleton. "
    [Show abstract] [Hide abstract] ABSTRACT: In humans, the hip joint occupies a central place in the locomotor system, as it plays an important role in body support and the transmission of the forces between the trunk and lower limbs. The study of the three-dimensional biomechanics of this joint has important implications for documenting the morphological changes associated with the acquisition of a habitual bipedal gait in humans. Functional integration at any joint has important implications in joint stability and performance. The aim of the study was to evaluate the functional integration at the human hip joint. Both the level of concordance between the three-dimensional axes of the acetabulum and the femoral neck in a bipedal posture, and patterns of covariation between these two axes were analysed. First, inter-individual variations were quantified and significant differences in the three-dimensional orientations of both the acetabulum and the femoral neck were detected. On a sample of 57 individuals, significant patterns of covariation were identified, however, the level of concordance between the axes of both the acetabulum and the femoral neck in a bipedal posture was lower than could be expected for a key joint such as the hip. Patterns of covariation were explored regarding the complex three-dimensional biomechanics of the full pelvic-femoral complex. Finally, we suggest that the lower degree of concordance observed at the human hip joint in a bipedal posture might be partly due to the phylogenetic history of the human species.
    Full-text · Article · Apr 2014
    • "Rudimentary buttressing was identifiable in anterior and posterior trajectories consistent with the mature adult iliac structure in specimens as young as 23–30 intrauterine weeks. In adult specimens, these trajectories are purported to be responsible for the transfer of weight between the auricular surface of the ilium and the femoral head at the acetabulum (Aiello and Dean, 1990; Scheuer and Black, 2000; Kapandji, 2011), and also to assist in the distribution of associated tensile forces (Macchiarelli et al., 1999 ). The discovery of corresponding , although immature, trajectories in the fetal ilium raised questions as to the cause of such precocious development, as the pelvis is not a weightbearing structure prior to birth (Walker, 1991 ) and traditional models postulate that bone structure is primarily dictated by mechanical stimuli (Wolf, 1892; Huiskes, 2000 ). "
    [Show abstract] [Hide abstract] ABSTRACT: Despite the importance of the human pelvis as a weight-bearing structure, there is a paucity of literature that discusses the development of the juvenile innominate from a biomechanical perspective. This study aims to add to the limited body of literature pertaining to this topic through the qualitative analysis of the gross architecture of the human ischium during the juvenile period. Macro-radiographs of 55 human ischia ranging from 28 intra-uterine weeks to 14 years of age were examined using intensity-gradient color mapping to highlight changes in gross structural morphology with increasing age. A clear pattern of maturation was observed in the juvenile ischium with increasing age. The acetabular component and ramus of the ischium consistently displayed low bone intensity in the postnatal skeletal material. Conversely the posterior body of the ischium, and in particular the ischial spine and lesser sciatic notch, exhibited increasing bone intensity which first arose at 1–2 years of age and became more expansive in older cohorts. The intensity patterns observed within the developing juvenile ischium are indicative of the potential factors influencing the maturation of this skeletal element. While the low intensity acetabular fossa indicates a lack of significant biomechanical interactions, the posterior increase in bone intensity may be related to the load-bearing nature of the posterior ischium. Clin. Anat., 2014. © 2014 Wiley Periodicals, Inc.
    Full-text · Article · Mar 2014
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