Fig 3. Schematic representation of a long bone cortex in cross-section.

The degree of vascularization, the orientation of vascular canals (i.e., longitudinal, laminar, radial, reticular, and plexiform orientations), and the degree of organization of the collagenous matrix (e.g., woven, lamellar, or parallel fibered) directly reflect relative, local bone depositional rates. Growth marks, including LAG and annuli, indicate intervals in which appositional growth decelerates significantly and/or stops completely. These growth slowdowns and stoppages can occur annually, irregularly, and/or at the termination of appositional growth once somatic maturity is attained. Secondary remodeling includes erosion and redeposition of bone within trabeculae, at the border of cortical bone with the medullary cavity (where it may form an IFS) and/or within compact bone tissue, where it is recognized by erosion rooms, secondary osteons and dense Haversian bone tissue. Schematized structures may not all necessarily be found together within a single section [1, 2, 4, 5 and included references].