Fig. 9

The histological findings of the lateral femur. a Creation of the histological section as described in Fig. 5. The microscopic findings of the marked area are shown in b–d. b Hematoxylin and eosin (HE) staining showing CB, PO, and FA (HE, × 4. scale bar: 500 μm). The low-powered HE-stained image shows the presence of a continuous layered structure in contact with the bone cortex. Sparse FA was present between the synovial surface of the joint cavity and the PO. c HE staining showing the fib, cam, and CB (HE, × 40. scale bar: 50 μm). d The layered structure is equally and deeply stained blue by Masson's trichrome (MT) stain and maintains its structure while gradually thinning from the distal to proximal direction (MT, × 4. scale bar: 500 μm). Therefore, these layered structures were considered to be the PO. e, f Periosteal thickness of the metaphyseal region on the (e) distal side and (f) proximal side (HE, × 4. scale bar: 500 μm). The periosteum gradually becomes thinner from the distal to the proximal side. g, h Periosteal thickness of the diaphyseal region on the (g) distal side and (h) proximal side (HE, × 4. scale bar: 500 μm). The periosteum of the diaphysis is relatively uniform and thin compared with that of the metaphysis