Articular cartilage: Histology and physiology

Abstract

Adult cartilage lacks blood vessels, lymphatics, and nerves and has three types: hyaline cartilage, fibrocartilage, and elastic cartilage. Hyaline cartilage is the most widespread cartilage and found in the nose, larynx, trachea, bronchus, ribs, and articular surfaces of bones. The surface of hyaline cartilage is surrounded by the perichondrium, a transitional zone between cartilage and the surrounding connective tissue, but articular cartilage lacks the perichondrium. The perichondrium consists of two layers: an outermost fibrous layer and the innermost chondrogenic cell layer. Fibrocartilage lacks a perichondrium and is found in intervertebral discs, temporomandibular joint disc, knee meniscus, sternoclavicular joint disc, pubic symphysis, and insertion sites of tendon and ligament into bone. The fibrocartilage has great tensile strength. Elastic cartilage is covered by the perichondrium and found in the external ear, auditory tube, and epiglottis. The specialized matrix of the elastic cartilage has flexibility and the ability to retain its original shape after an applied force.