What are intramembranous and endochondral ossification?

The direct conversion of mesenchymal tissue into bone is called intramembranous ossification .The process by which a cartilage intermediate is formed and replaced by bone cells is called endochondral osssification.

Explanation:

Intramembranous ossification  is one of the two essential process during the fetal development  of the gnathosome skeltal system by which rudimentary bone tissue is created. It is the process of bone development from fibrous membranes. It is involved in the formation of the flat bones of the skull, mandible and the clavicle. This type of ossification also helps in healing of bone fractures.

Endochondral Osssification: Method of forming a bone through cartilage intermediate. It is also involved in the formation of long bones.