intramembranous ossification vs intra-cartilaginous ossification

 Intra membranous ossification 

The process of developing bones where bone tissue grows directly within a mesenchymal membrane is called intramembranous ossification. The flat bones of the skull, face bones, and clavicles are where this process mostly takes place. The following actions are involved:

Osteoblasts, or cells that create bones, are differentiated from mesenchymal cells.
The organic matrix (osteoid) secreted by osteoblasts is mineralized with calcium salts to produce bone tissue.
Some osteoblasts become stuck in the matrix during the formation of bone tissue and develop into osteocytes, or mature bone cells.
As the bone develops, blood vessels sprout inside it to carry nutrients and oxygen.

Intra cartilaginous ossification 

On the other hand, a process of bone growth called intra-cartilaginous ossification, or endochondral ossification, occurs when bone tissue replaces a model of cartilage. The majority of the body's bones go through this process, even lengthy bones like the femur and humerus.

In a model of hyaline cartilage, mesenchymal cells develop into chondrocytes, or cartilage cells.
The cartilage model's center's chondrocytes grow, or undergo hypertrophy.
Osteoblasts and osteoclasts are brought into the hypertrophic cartilage by blood vessels.
On the remaining cartilage model, osteoblasts deposit bone matrix to form trabeculae, or spongy bone.
A medullary cavity is generated by osteoclasts breaking down portion of the newly formed bone.
The spongy bone is surrounded by compact bone as the bone continues to develop and remodel.