bones

Long bones

Bones that are longer than wide, such as the humerus and femur.

Short bones

Bones with dimensions roughly equal, like carpal and tarsal bones.

Flat bones

Bones that are thin and relatively broad, including parietal bones in the skull, ribs, and scapulae.

Irregular bones

Complex bones that do not fit into any other category, such as vertebrae and pelvis.

Diaphysis

The central shaft of a long bone, which surrounds the marrow cavity.

Marrow cavity

The space surrounded by the diaphysis, containing bone marrow.

Bone marrow

Soft fatty tissue that fills marrow cavities.

Epiphyses

Expanded portions at the ends of the diaphysis, covered with articular cartilage.

Articular Cartilage

Tissue that covers the epiphyses.

Compact bone

Dense bone that fills the diaphysis.

Spongy bone

Bone that resembles a network of bony rods/struts separated by space, filling the epiphyses.

Periosteum

The outer surface of a bone.

Endosteum

The tissue that covers the spongy bone of the marrow and other inner surfaces.

Lacunae

Small pockets found between narrow sheets of calcified matrix known as lamellae.

Lamellae

Narrow sheets of calcified matrix.

Canaliculi

Small channels that radiate through the matrix and link lamellae to blood vessels, enabling nutrient and waste exchange.

Osteon

The functional unit of compact bone.

Trabeculae

Structures found in spongy bone that are formed by lamellae.

Osteocytes

Mature bone cells located in lacunae; they maintain bone structure by recycling calcium salts and assisting in repairs.

Osteoclasts

Cells that dissolve the bony matrix and release osteolysis.

Osteoblasts

Cells that produce new bone matrix; they add as osteoclasts remove.

Ossification

The process of producing new bone.