Bone Anatomy
From the ends of the bone inward is the:
- Epiphysis,
- It provides the cap to the bone and is covered in articular cartilage for the joint space.
- Epiphyseal plate (aka the growth plate or physis)
- When the growth plate closes it forms the epiphyseal line.
- This separates the epiphysis and the metaphysis.
- Metaphysis
- Diaphysis
- This is the bone shaft. It contains the medullary (marrow) cavity.
collagenous structures
- Articular cartilage is derived from hyaline cartilage, at its ends.
- Periosteum, along the shaft, is derived from a condensation of outer connective tissue.
- It comprises an external layer of collagens fibers and vasculature and an internal layer of osteoprogenitor cells.
- Endosteum, centrally, is derived from derived from a condensation of inner connective tissue and helps separate the marrow cavity, internally, from the compact bony matrix that encapsulates it.
- It comprises an inner parallel-layered lamellae and osteoprogenitor cells.
marrow cavity
- Filled with hematopoetic marrow (red blood cell and white blood cell precursors) and fatty marrow (adipose tissue).
- It comprises stem cells, which can self-renew, committed precursor cells, and cells that are in the process of maturation.
Bone Tissues
- Compact bone forms the outer layer of bone.
- Spongy bone forms the inner mass of bone.
- It comprises a network of lamellae that do NOT form the Haversian channels and osteons found in compact bone.
- The marrow cavity forms within the center of bone.