II. Physiology: Development
- Hyaline Cartilage
- Hyaline cartilage is the initial structure or mold into which bone forms
- Bone Collar
- Forms along the outer margin of the bone (at future diaphysis)
- Primary Ossification Center
- Hyaline cartilage deteriorates and cavitates centrally forming a hyaline cavity
-
Medullary (central) spongy bone formation
- Spongy bone forms centrally from primary Ossification Center
- Periosteal Bud
- Vascular connective tissue from the perichondrium (outer margin) invades central hyaline cavity
- Forms future blood supply to Medullary cavity
-
Medullary cavity
- Bony cavity replaces prior hyaline cartilage cavity
- Secondary Ossification Center
- Spongy bone forms from secondary Ossification Center (at each long bone end)
- Develops into epiphyseal bone
- Epiphyseal Plate cartilage (epiphysis or Growth Plate)
- Cartilage remains between bone formed from primary (central) and secondary (epiphyseal) Ossification Centers
- Remaining cartilage functions as a Growth Plate for Long Bone Growth
- Articular cartilage
- Hyaline cartilage remains at the long bone ends at joint margins
- All other hyaline cartilage is replaced by bone, aside from at the epiphysis
III. Anatomy: Layers
- Articular cartilage
- Epiphysis (rounded bone end)
- Epiphyseal Plate or Growth Plate (Hyaline Cartilage)
- Resting Zone (or Reserve Zone)
- Proliferating Zone (or proliferative zone)
- Hypertrophic Zone
- Metaphysis
- Primary Spongiosa
- Secondary Spongiosa
- Diaphysis