Scanning electron microscopy of bone-tendon junction of the calcaneal tendon of adults Wistar rats (A, C, E) and elderly Wistar rats (B, D, F). (A, B) Calcaneal tendon (T) and bone (B). Bar: 50 and 100 μm, magnification x200 and x160 respectively. (C) Collagen fiber of the tendon (small arrow), lacuna of fibrocartilage cell in the tendon tissue (larger arrow), lacuna of fibrocartilage cell in the bone (arrowheads), bone (B). Bar: 10 μm, x1,000. (D) Collagen fiber of the tendon (**) and bone (B). Bar: 10 μm, x1,000. (E) Lipid droplets (arrowheads), collagen fibers of the tendon tissue (arrows). Bar: 2 μm, x3,000. (F) Lipid droplets (arrowheads), bundles of collagen fibers of the tendon tissue (*). Bar: 2 μm, x3,000.