6.4: gross structure of bones

Compact bone

The dense outer layer of bone that appears smooth and solid.

Spongy bone

The bone internal to compact bone that consists of needle-like or flat pieces called trabeculae.

Trabeculae

Needle-like or flat pieces that make up spongy bone.

Diploë

The spongy bone inside short, irregular, and flat bones; it houses bone marrow between the trabeculae.

Diaphysis

The tubular shaft of a long bone.

Medullary cavity

The hollow cavity within the diaphysis that is filled with yellow bone marrow in adults.

Yellow bone marrow

The marrow that fills the medullary cavity of adult long bones.

Epiphyses

The ends of a long bone; contain internal spongy bone covered by compact bone and a thin layer of articular cartilage.

Articular cartilage

A thin layer of cartilage covering the ends of the bone at the epiphyses.

Epiphyseal plate

A plate of hyaline cartilage that provides lengthwise growth of bone.

Epiphyseal line

The remnant of the epiphyseal plate.

Periosteum

The membrane covering the external surface of bone; it contains osteogenic cells.

Endosteum

A connective tissue membrane lining the internal surface of bone; it contains osteogenic cells.

Nutrient foramen

An opening in the diaphysis through which blood vessels and nerves enter the bone.