The perichondrium (from Greek περί (''peri'' 'around') and χόνδρος (''chondros'' 'cartilage')) is a layer of dense irregular connective tissue that surrounds the cartilage of developing bone. It consists of two separate layers: an outer fibrous layer and inner chondrogenic layer. The fibrous layer contains fibroblasts, which produce collagenous fibers. The chondrogenic layer remains undifferentiated and can form chondroblasts or chondrocytes. Perichondrium can be found around the perimeter of elastic cartilage and hyaline cartilage. Fibrocartilage and articular cartilage both lack perichondrium.