Biomedical Engineering Reference
In-Depth Information
A
Diffuse
damage
Cross-hatching
Linear
microcrack
B
Haversian canal origin
of 'cutting cone'
Remodeling
'cutting cone'
Microcrack
2.12
Microdamage in bone. (A) Trabecular bone strut stained with
basic fuchsin demonstrating three types of microdamage. (B)
Interstitial cortical microcrack that is the target of remodeling activity
(panel A reproduced with permission of Elsevier from Fazzalari
et
al
.
236
Panel B courtesy of Dr. David B. Burr, Indiana University School
of Medicine).
found in cortical interstitial lamellae and are frequently limited by osteonal
cement lines. diffuse damage is more frequently found in trabecular bone
and is identified by an intensely stained mineralized matrix which represents
areas containing many small cracks each of the order of a micrometer in
size.
173
also, common in trabecular bone are intermediate-sized cracks
arranged in a cross-hatched pattern (cross-hatched cracks) and completely
fractured trabecular struts (microfractures).
174
Microdamage is a mechanically related phenomenon. Its formation is
both strain magnitude and rate dependent, with increases in either beyond
threshold levels resulting in increased damage formation.
175-178
damage is
also influenced by the total number of bone loading cycles, with its formation
occurring at physiological strains in response to pure cyclic overloading.
179
