Cartilage perichondrium, light micrograph. The perichondrium (upper frame, reddish) is a connective tissue sheath that surrounds the cartilage. It has a fibrillar appearance due to bundles of collagen fibres cut in different planes. Below is the cartilaginous tissue showing rounded chondrocytes organized in small cell groups, called isogenic groups. The deeper you go into the cartilage tissue, the matrix that surrounds the chondrocytes is more bluish, as it is richer in amorphous substance.