A distinct region of microarchitectural variation in femoral compact bone: Histomorphology of the endosteal lamellar pocket

Abstract

Bone is a dynamic tissue, responding locally to differential mechanical loading and systemically to hormonal stimuli. Although the tendency is to consider compact bone a homogenous tissue, regional variations in microarchitecture are known to have quite different properties relating to processes of growth and mechanical loading. Specifically, we investigated an example of microstructural variation of the human, adult femoral endocortex, referred to here as the endosteal lamellar pocket (ELP). The femoral ELP is characterised as a histomorphological meta-feature, made distinct from general circumferential lamellae by its hemicircumferential lamellar orientation, medial positioning, radially oriented Volkmann's canals and decreased presence of Haversian systems. Our preliminary observations of mid-diaphyseal transverse thin-ground sections demonstrate the ELP as a regular meta-feature of adult human femora unearthed from the Maya archaeological site of Xcambó , Mexico. ELPs were easily identified in 38 of 45 examined individuals. Their size, shape and degree of secondary remodelling were variable. In comparison, ELP lamellae and those originating from the periosteum are divergent, or non-concentric in orientation. This divergence, along with the ELP's medial position, suggest it forms during growth through endosteal modelling drift. Possible considerations for ELP formation and persistence with age are discussed as well as its implications for the study of bone dynamics during growth and activity. Further research is necessary to quantitatively measure the morphology of ELPs and to identify any co-variance between ELP characteristics and age, sex or indicators of mechanical loading.

Drifting Diaphyses: Asymmetry in Diametric Growth and Adaptation Along the Humeral and Femoral Length

“…While midshaft cross‐sections are sufficient to gain information about general drift directions and magnitudes, additional longitudinal sections permit a much more detailed interpretation and are essential to an improved understanding of modeling drift. The application of the starburst point‐count technique in this study captured regional variations in tissue distribution sufficient for statistical analysis, and confirmed previously reported modeling drift patterns (deriving from qualitative or cortical surface techniques) (Goldman et al, ; Maggiano et al, ). One limitation of our study and its comparability with others is the lack of a standardized method for the determination of anatomical axes on dry bone.…”

Collagen Fiber Orientation in Primate Long Bones

“…Endosteally deposited tissues in this sample are frequently bright in CPL, at least more so than periosteal and intracortically remodeled tissues. This pattern of endosteal brightness has been observed by other researchers (Carando et al, ; McMahon et al, ; Bromage & Boyde, ; Maggiano et al, ) but has not been satisfactorily explained in terms of either mechanical adaptation or mechanisms of growth and development. Nor can we offer here a persuasive explanation for our observations.…”

Spatial variation in osteon population density at the human femoral midshaft: histomorphometric adaptations to habitual load environment

“…; Maggiano et al. ). Thus through development, some areas of the cortex that existed in early life are completely removed, and entirely new areas of bone are deposited.…”

“…By late childhood, modeling drift in the femur shifts direction to primarily lateral and/or anterolateral and continues in this direction through skeletal maturation ( Fig. 8; Goldman et al 2009;Maggiano et al 2011). Thus through development, some areas of the cortex that existed in early life are completely removed, and entirely new areas of bone are deposited.…”