Cartilage is widely distributed in all parts of the body. In a normal adult, for example, cartilage is distributed from head to toe, in the larynx, forming laryngeal cartilage, in the epiglottis, tracheal cartilage, bronchial cartilage, nasal cartilage, external ear cartilage, intervertebral disc cartilage of the cervical spine, and thoracic and lumbar intervertebral disc cartilage, as well as rib cartilage in the anterior thorax. Most of the cartilage in the human body is distributed in all the joints that can move, forming articular cartilage, such as rib cartilage, laryngeal cartilage, nasal cartilage, etc. will degenerate and calcify as we age. After puberty, calcification of the rib and laryngeal cartilage in particular is very common, and the middle-aged and elderly will see obvious foci of calcification when examining X-rays of the corresponding locations, and the regenerative capacity of this cartilage is poor. The articular cartilage in the joints, except for the intervertebral cartilage, has a very smooth surface and there is almost no friction when the joints move. The deformability and elasticity of the intervertebral cartilage is so strong that disc herniation often occurs.