Light micrograph of the epiphyseal growth plate of a developing long bone. The epiphyseal cartilage shows the following layers, from top to bottom: resting hyaline cartilage, zone of proliferation, zone of hypertrophy with large lacunae, zone of calcification (not visible as such, but can be identified by the degeneration of the chondrocytes leaving empty cartilaginous lacunae), and an ossification zone of compact appearance, where there is an invasion of blood vessels and osteogenic cells.