Viewing a bird bone through an electron microscope reveals an intricate and lightweight structure, optimized for flight. The bone's internal composition is a complex lattice of trabeculae—thin, rod-like structures that provide strength while minimizing weight. This spongy or cancellous bone is filled with air pockets, reducing the overall density and making the bone both strong and light. The outer surface is covered with a dense layer of compact bone, providing additional rigidity. The fine details visible at the electron microscope level, including the collagen fibers and mineral crystals, illustrate how bird bones achieve a perfect balance between strength and lightness, essential for avian flight.