Osteocyte lacunocanalicular microstructure across the midshaft femur in adult males from Medieval England

Archaeological human bone histology can reveal well-preserved osteocyte lacunae, which are indicators of bone remodeling activity. Analyses of these lacunae can be useful when reconstructing past human mechanical loading histories or metabolic fluctuations from bone microstructure. However, the relationship between osteocyte lacunae and bone anatomical variation within archaeological samples is largely unknown. We examined osteocyte lacunocanalicular network morphology in Medieval human femora to test if osteocyte lacunae change with anatomical site location. Osteocyte lacunae density (Ot.Dn) data were analyzed statistically in ten middle-aged (35-50 years old) males dated to the 11th-16th centuries AD (Canterbury, England). A subsequent case study was conducted using two well-preserved samples from which canaliculi number per lacuna (Ci.N) and canaliculi-rich lacunae density (Ci.Dn) were preliminarily examined descriptively. The data were collected from cortical bone regions encompassing intra-cortical to sub-periosteal midshaft femur bone, comparing anterior, posterior, medial, and lateral locations inter- and intra-individually. Results show that Ot.Dn varied significantly between the four anatomical regions (p = 0.001), with the medial and lateral femur regions showing the highest median Ot.Dn. The median of Ci.N was also the highest on the medial aspect, but Ci.Dn did not change largely across all four bone aspects. The combination of these results suggests that midshaft femur anatomical location, which undergoes morphological change with biomechanical load, affects the expression of bone microstructure at the osteocyte lacuna level. This knowledge will benefit future osteoarchaeological methods that infer past behavior from the human femur.