Fig. 4

Multi-technique imaging of the exposed vessel-like structure surface from RSKM P2523.8. (A–G) Analysis of the vessel-like structure corresponding to Fig. 3B–D (red arrow). (A) Optical and (B) cross-polarized light microscopy of the structure using a thin section slide produced from the bone section of Fig. 1B,C. The structures appears completely opaque compared to the surrounding bone matrix. In this orientation original bone osteons are above the vessel, and callus bone osteons are below the vessel. (C, F) SEM analysis of the bone section of Fig. 1B,C, with white arrows showing correspondence to the same Haversian canal. (C) Back scattered electron image of the structure, showing brighter areas that have higher atomic number composition. (F) RGB map showing the relative amounts of oxygen, sulphur, and phosphorus in the structure. (D, E, G) VESPERS beamline chemical mapping at CLS. Pixel resolution = 5 \(\upmu\)m. (E) Calcium, iron, and manganese RGB map of the structure. (D) Iron concentration map of the structure, the most dominant element. (G) Zoom of (D) showing the heterogeneity of the iron in the structure, with areas of reduced iron shown. (H) BSE image of another vessel-like structure with 3DCT correspondence to Fig. 3C,D (green arrow), featuring a distinct outer layering. (I) BSE image of a structure in Zone 1 with similar morphology to (H), but with no 3D correspondence.