The relationship between musculoskeletal stress markers and biomechanical properties of the humeral diaphysis

Abstract

Musculoskeletal stress markers (MSM) at entheses and bone biomechanical properties are used in activity reconstructions. The effect of physical activity on bone biomechanical properties is well established but the relative role of physical activity on MSM is less well known. In this article, it is hypothesized that the same causal mechanisms should affect MSM development as those responsible for bone biomechanical properties. Further, there should be a correlation between MSMs and bone cross-sectional properties as both are considered to reflect physical activity. This was tested using three skeletal samples: early 20th century Finnish (Helsinki) and two medieval English (Blackgate and York) populations. Torsional/average bending rigidity (J) for four cross-sectional locations at 80, 65, 50, and 35% of humeral length from the distal end was calculated and pectoralis major, teres major, and deltoid were scored for MSM. Correlations between MSM and size-standardized J were significant for many comparisons, although they were stronger in males than in females, especially on the right side. In ANOVAs, sample was found to be a significant influence on the right side in both sexes. Using an aggregated MSM score, covariance between J and high MSM scores was again stronger in males. Covariance between J and MSM was found both at cross-sectional locations under muscle insertions and at more distant locations, demonstrating both direct and general effects of muscular loadings applied to diaphyses. Thus, the two types of skeletal markers appear to be related to similar underlying mechanical factors, but effects may also be sex- and sample-specific.

Septal aperture aetiology: still more questions than answers

“…Taking into account that number of conducted studies, we may confirm that individuals with more massive bones have stronger muscles [5,26,31,41,47], and also suggest the same aetiology of muscle markers and bone robusticity should not be surprising. However, this requires caution, as some researchers are sceptical towards the existence of the relationship between bone robusticity and muscle marker formation, underlining the multifactorial aetiology of bone development [6,41,48].…”

Bone microarchitecture at muscle attachment sites: The relationship between macroscopic scores of entheses and their cortical and trabecular microstructural design

“…Although muscle activity was frequently linked to overall bone cross-sectional geometry (Ruff et al, 2006;Niinim€ aki, 2012;Niinim€ aki et al, 2013), further experimental or simulation studies are necessary to check whether or how mechanical strains derived from the muscle contraction dissipate along the diaphysis, or if they mostly concentrate at the insertion sites (Schlecht, 2012b). To this goal, the comparison of cortical thickness between muscle attachments sites and the surrounding bone might offer some clues.…”

“…In order to reduce error variance, Weiss (2003Weiss ( , 2004 used "aggregate measures", i.e., the sum of a minimum of 7 insertion sites for upper and 20 insertion sites for lower limbs. Hirschberg (2005) investigated the biomechanical basis for the development of a tubercle or a pit at the location of the muscle attachment site, while Niinim€ aki (2012) analyzed the effects of physical activity on bone structural adaptations by studying the relationship between EC and the cross-sectional geometry of long bones.…”

Una aproximación estadística al estudio de los cambios entésicos empleados para evaluar diferencias sexuales en restos humanos

“…Se decidió dividir la muestra en dos rangos etarios porque, en primer lugar, de esta manera cada categoría tiene un tamaño de muestra aceptable para realizar comparaciones estadísticas, que de lo contrario (si se fragmenta la muestra en mayores rangos etarios), la cantidad individuos en cada uno de ellos sería muy baja. En segundo lugar, el punto de quiebre de 40 años es apropiado ya que luego de esta edad se manifiesta una mayor pérdida ósea y cambios osteoporóticos que impactan en la morfología de las entesis (Niinimäki 2012).…”