Concentric lamellae are the layers of compact bone tissue that make up the fundamental structure of cortical bones in most mammals. Lamellae, which translates to "little plates," are part of the Haversian system.
Microscopic layers of lamellae form in concentric circles around Haversian canals, through which run a bone's vascular system. Sections of these concentric circles are called osteon. An osteon typically measure less than one half of one millimeter in diameter and as much as 10 millimeters in length.
There are two types of osteons: primary and secondary. Secondary osteons are formed by the remodeling of existing bone and contain more lamellae. Because of this, concentric lamellae are found primarily in mature cortical bones.