Bone 2

Morphology of a Long Bone

• Diaphysis

• Metaphysis

• Epiphysis

• Epiphyseal Plate

Diaphysis

• Bone shaft between epiphyseal plates

• Mostly compact bone; metaphysis is spongy bone (cancellous)

• Periosteum• Endosteum• Marrow cavity

Articularcartilage

Epiphysis

Epiphyseal plate

Metaphysis

Diaphysis

Metaphysis

Epiphyseal plate(hyaline cartilage)

Epiphysis

Articular cartilage(hyaline cartilage)

Cancellous bone

Cancellousbone

Perichondrium

Medullarycavity

Compact bone

PeriosteumEndosteum

Metaphysis

• Distal ends of diaphysis

• Spongy (cancellous) bone

Epiphysis

• Distal ends of long bones

• Articular cap of hyaline cartilage

• Medullary cavity is cancellous and contains a marrow cavity

Epiphyseal plate

• Junction between diaphysis and epiphysis

• Hyaline cartilage in child• Responsible for bone growth• Periosteum become continuous

with a perichondrium

Compact bone

• Periosteum• Endosteum• Haversian system (osteon)• Volkmann’s canals• Interstitial lamellae• Outer circumferential lamellae• Inner circumferential lamellae

Periosteum

• Fibrous (outer) layer– Fibroblasts; collagen; elastin– Protection of bone

• Osteogenic (inner) layer– Osteoblasts adjacent to bone surface– Osteoprogenitor cells-precursors to

osteoblasts– Osteoclasts if remodeling is occurring

Periosteum

• Blood vessels & nerves present

• Sharpey’s fibers: anchor periosteum to bone

Endosteum

• Between bone marrow and bone matrix

• Layer of osteoblasts, osteoclasts, and a few osteogenic cells

Innercircumferential

lamellae

Interstitiallamellae

Haversian system (osteon)

Outer circumferentiallamellae

Volkmann’s canal

PeriosteumHaversian canal

Haversian System (osteon)

• Concentric lamellae of bone– Up to ~ 10 lamellae/osteon– Osteocytes and canaliculi– Collagen planes in adjacent lamellae

are perpendicular to each other

• Surround vascular passageways running longitudinally

• Contain blood vessels, nerves, lymphatics

Innercircumferential

lamellae

Interstitiallamellae

Haversian system (osteon)

Outer circumferentiallamellae

Volkmann’s canal

PeriosteumHaversian canal

Volkmann’s canals

• Observed in compact bone• Vascular passages that run radially• Not surrounded by concentric

lamellae• Contain blood vessels, nerves, and

lymphatics

Innercircumferential

lamellae

Interstitiallamellae

Haversian system (osteon)

Outer circumferentiallamellae

Volkmann’s canal

PeriosteumHaversian canal

Interstitial lamellae

• Remnants of partly resorbed osteons

• No vessels

Innercircumferential

lamellae

Interstitiallamellae

Haversian system (osteon)

Outer circumferentiallamellae

Volkmann’s canal

PeriosteumHaversian canal

Outer circumferential lamellae

• Beneath periosteum

• Usually do not encircle entire bone shaft

Inner circumferential lamellae

• Adjacent to endosteum

• Incomplete

Innercircumferential

lamellae

Interstitiallamellae

Haversian system (osteon)

Outer circumferentiallamellae

Volkmann’s canal

PeriosteumHaversian canal

Fullyformedosteon Developing osteon

Osteoblast

Prebone

Cementing lineHaversian canal(with capillary)

EndBone 2

Haversian canal Lamellae Lacuna Cement

ProcessesOsteocytes