Anatomy of a Long Bone

1. Articular cartilage - lines the joint surface, cushion and allow smooth motion
2. Epiphyseal line - fusion of epiphyses & diaphysis - indicates bone fully grown
3. Spongy Bone - internal network of osteocytes creating a strong structure with empty cavities that contain red marrow - found towards and within epiphyses
4. Red Marrow - connective tissue that generates Red Blood Cells - in spongy bone
5. Compact Bone - dense, mineralized, rigid bone of the diaphysis and outer layers
6. Yellow Marrow - fatty connective tissue that generates white blood cells
7. Periosteum - connective membrane found on the outside of the bone
8. Endosteum - connective membrane found lining the medullary cavity
9. Medullary Cavity - empty space within diaphysis that contains yellow marrow
10. Epiphysis (epiphyses) - the “ends” of the bone
11. Diaphysis - the “shaft” of the bone

Epiphysis

Epiphysis

Diaphysis

Yellow Marrow in Medullary Cavity

Compact Bone

Spongy Bone

Red Marrow

Spongy Bone

Red Marrow

Articular Cartilage

Endosteum

Periosteum

Epiphyseal Line

Note that this diagram to the left shows the compact and spongy bone in a flat bone (like in your cranium)

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The diagram at the bottom shows a cross-section of the spongy bone. Note the osteocytes in between the layers (lamellae) and the bone building and removing osteoblasts/ osteoclasts.