GENERAL HISTOLOGY

Detailed explanation-1: -Primary ossification center forms in the diaphyseal region of the periosteum called the periosteal collar. Secondary ossification centers develop in the epiphyseal region after birth.

Detailed explanation-2: -A secondary ossification center will appear in each epiphysis (expanded end) of these bones at a later time, usually after birth. The primary and secondary ossification centers are separated by the epiphyseal plate, a layer of growing hyaline cartilage. This plate is located between the diaphysis and each epiphysis.

Detailed explanation-3: -The long bone in a child is divided into four regions: the diaphysis (shaft or primary ossification centre), metaphysis (where the bone flares), physis (or growth plate) and the epiphysis (secondary ossification centre).

Detailed explanation-4: -A secondary ossification center is the area of ossification that appears after the primary ossification center has already appeared – most of which appear during the postnatal and adolescent years. Most bones have more than one secondary ossification center. In long bones, the secondary centers appear in the epiphyses.