Cartilage is divided into 4 parts based on structure. These are-
- Clear or Hyaline Cartilage: The cartilage matrix is clear, firm, flexible, homogenous, bluish and elastic. It is covered by the perichondrium. It contains no fibers. It contains cavities called lacunae. Inside the lacunae are chondrocytes or chondroblasts. This cartilage is present in the nose, trachea, larynx, larynx, larynx of mammals, bones and embryos of vertebrates.
- Biliary Cartilage: The matrix of this cartilage is opaque, elastic and light yellow in color. Yellow colored fibers are scattered in it. The fibers are branched and scattered. It is covered by the perichondrium. It contains cavities called lacunae. Inside the lacunae are chondrocytes or chondroblasts. It is present in external ear, pinna, tongue, eustachian tube, epiglottis, larynx, lymph nodes etc.
- White Cartilage: The matrix of this cartilage is opaque and colorless. It has white fibers. The fibers are unbranched and arranged parallel and in clusters. It is covered by the perichondrium. It contains cavities called lacunae. Inside the lacunae are chondrocytes or chondroblasts. It lies between the joints and vertebrae.
- Calcified or calcareous cartilage: This cartilage matrix contains a large amount of calcium carbonate. Its matrix is rock solid. It resides in the head of the humerus and femur.