Which event has to proceed all others during endochondral ossification?

Hyaline cartilage model formation is the event that should proceed all others during endochondral ossification.

Explanation:

The Greek root word for cartilage is 'chondro'. Endochondral ossification is the systematic formation or replacement by bones to develop the growing skeleton from a growing cartilage. Mesenchymal cells are converted to chondroblasts to chondrocytes and then to a hyaline cartilage model. This leads to the development of long bones of both the axial (ribs) and the appendicular skeleton (limb bones). The sites of endochondral ossification are the physis, epiphysis, and cuboidal bones. The five main steps involved in endochondral ossification are - Bone collar formation Cavitation Periosteal bud invasion Diaphysis elongation Epiphiseal ossification