Bone structures are the rigid frameworks that make up the skeleton in vertebrates, providing support, shape, and protection to the body. They are primarily composed of a mineralized matrix, which includes collagen fibers and minerals like calcium and phosphorus. This composition gives bones their strength and durability while allowing for some flexibility. There are two main types of bone structures: cortical bone and trabecular bone. Cortical bone is dense and forms the outer layer of bones, while trabecular bone, also known as spongy bone, is lighter and found within the interior. Together, these structures play crucial roles in movement, blood cell production, and mineral storage.