A comparison of bone growth by Intramembranous Ossification vs. Endochondral Ossification . . . . . Growth of cartilage model Mesenchyme - differentiates into osteoprogenitors, osteoblasts . . . Nutrient artery stimulates bone formation in periosteal region Osteoblasts form spongy bone . . . Spongy bone grows outward . . . Formation of primary ossification center spongy bone replaces cartilage interior Periosteum developed . . . .
Osteoclasts form marrow cavity . . . .
Bone grows outward in two directions . . . .