Cross-section of cortical long bone, polarised light micrograph. The osteons appear as rounded structures with a small central space that is the Haversian duct. With polarised light, the arrangement of concentric lines (the bone lamellae) stands out around this canal, where some bright and dark alternate. In addition, the formation of an image in the shape of a Maltese cross is striking. Bony lamellae are also found between the osteons, alternating bright with dark, and together they correspond to the interstitial gaps or lamellae.