Lamellae are thin layers of bone matrix that form concentric rings around the Haversian canal. They are composed of collagen fibers arranged in a helical pattern, which gives the bone its tensile strength. There are three types of lamellae: concentric, interstitial, and circumferential. Concentric lamellae are found within osteons, while interstitial lamellae are remnants of old osteons that have been partially resorbed. Circumferential lamellae run around the outer and inner surfaces of the bone, just beneath the periosteum and endosteum, respectively.
