The earliest form of spongy bone in a developing long bone is termed as Osteoid.
<em>Osteoid is defined as the the unmineralized, matrix material that is made up of a fibrous protein, collagen, and mucopolysaccharide and forms prior to the maturation of bone tissue. </em>
Osteoblasts, the process of formation of bones takes place when inorganic salts starts depositing over osteoid to form the hardened material.
