Fig. 2.

Classification of cartilage present in vertebrates. Temporary cartilage appears during development to accomplish skeletal formation and growth. A class of temporary cartilage, here termed bone-directed cartilage, itself is mineralized to become bone under the collaboration with osteoblasts and vascular endothelial cells. In the case of bone-inducing cartilage, bone is formed independently at a space in close proximity. Permanent cartilage is formed and maintained to add elasticity and stiffness required in certain organs. Based on the physical property, histological characteristics, and ECM composition, permanent cartilage can be classified as hyaline, elastic or fibrous