This macrograph shows the spongy bone from a human thigh bone (the femur), magnified approximately 8 times. Spongy bone is found at the expanded ends of long bones, such as the bones of the arms, legs, fingers and toes. It also makes up the bulk of irregular bones like the skull and vertebrae. The open mineral structure seen here, composed of interconnected trabeculae, is surrounded in life by blood vessels and bone marrow. The spongy structure is both light and strong, and is especially resistant to bending and stretching.