The diagram illustrates the appearance of an osteon (Haversian system) in 3D. The osteon is the unit or building brick of compact bone and consists of a column of bone with layered subunits called lamellae. In this artistic rendering the inner most lamella has been pulled upward, dragging and stretching the sequential lamellae so as to display the morphology of all the lamellae in the osteon. The lamellae consist of calcium, phosphate, and hydroxyl ions which form a compound called hydroxyapatite (Ca5(PO4)3(OH) – seen in (a) as shades of white and gray overlay. The hydroxyapatite gives bone its hardness. The lamella also contains type I collagen fibers. (color overlay of reds and pinks on the white background) that are arranged in different directions on adjacent lamellae so that a zig zag pattern of the collagen is created allowing for strengthening of the tissue. The collagen provides elasticity. Lacunae (c, black holes) are spaces in the lamellae that house the osteocytes (d). The canaliculi(c black web) are a network of fine tubular channels that allow the osteocytes to communicate with each other. The Haversian canal is the space seen on the top and in the middle of the osteons that contains artery, vein and nerve (a-d).
Courtesy Ashley Davidoff Copyright 2011 106275c03L13.8s