The following are major steps in the process of endochondral ossification: 1. Bone forms at the diaphysis surface. 2. Secondary ossification centers form in the epiphyses. 3. Chondrocytes enlarge and calcify. 4. Osteoclasts create a marrow cavity. 5. Blood vessels invade the inner cartilage and new osteoblasts form spongy bone at a primary ossification center. The correct order for these events is