Bone Structure

Long Bone Anatomy

• Diaphysis – Shaft -Composed of compact bone

• Epiphysis – Ends – Spongy bone surrounded by compact bone

• Periosteum – Fibrous protective membrane that covers the diaphysis

• Perforating fibers – Connective tissue fibers that attach periosteum to bone

• Articular cartilage – Glassy, smooth hyaline cartilage layer that covers the epiphysis – Helps reduce friction

Long Bone Anatomy (Cont.)

• Medullary canal – Canal in the center of the bone

Adults – Fat storage (yellow marrow)

Infants – Filled with red marrow (makes blood cells)

• Red Marrow – Responsible for hematopoiesis

Adults – Found in cavities of spongy bone

Infants – Found in medullary canal

Long Bone Anatomy (Cont.)

• Epiphyseal line – Remnant of the epiphyseal plate

• Epiphyseal plate – Flat plate of hyaline cartilage – Site of the lengthwise growth of bone

Anatomy of an Osteon

• Osteocytes – Mature bone cells found in the lacunae

• Lacunae - Tiny cavities in bone matrix that contain osteocytes

• Lamellae – Circles in the bone tissue that contain the lacunae – Look like tree rings

• Haversian canal – Canal in the middle of the osteon – Allows neurovascular bundles to pass through

Anatomy of an Osteon (Cont.)

• Canaliculi – Tiny canals radiating from Haversian canal to all lacunae

• Volkmann’s (Perforating) Canal – Canals that run at a right angle to the Haversian canal