Osteocyte lacuno-canalicular microstructure across the mid-shaft femur in adult males from medieval England

Archaeological human bone histology can reveal well-preserved osteocyte lacunae, which are indicators of bone remodelling 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 density and morphology, and bone anatomical variation within archaeological samples is largely unknown. We examined osteocyte lacuno-canalicular network morphology in medieval human femora to test if osteocyte lacunae change with anatomical site location. Osteocyte lacunae density (Ot.Dn) data were analysed statistically in 10 middle-aged (35–50 years old) males dated to the 11th–16th century AD (Canterbury, England). A subsequent case study (n = 2) 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 intracortical to subperiosteal mid-shaft femoral bone, comparing anterior, posterior, medial and lateral locations interindividually and intraindividually. Results show that Ot.Dn varied significantly between the four anatomical regions (p = 0.001), with the medial and lateral femoral 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 greatly across the four apects of the bone. The combination of these results suggests that mid-shaft femoral 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 behaviour from the human femur.