How does bone marrow fit within the internal structure of bones?

Bone marrow is a soft, vascular tissue that occupies the internal cavities of bones. Its placement within the skeletal structure depends on the type of bone and the tissue's function:12

• Cancellous Bone: In spongy or cancellous tissue—found in areas like the vertebrae, ribs, and the ends of long bones—marrow fills the spaces between a network of intersecting plates and spicules called trabeculae.32
• Medullary Cavity: In long bones, such as the femur, the central region known as the diaphysis contains a continuous hollow space called the medullary cavity, which is also filled with marrow.32

In adults, red marrow (responsible for blood cell formation) is primarily located in flat bones and the ends of long bones, while yellow marrow (a fat storehouse) occupies the central cavities of long bones and other cancellous areas.12