Unhealthy areas were identified as irregularities and obvious defects in extracellular matrix organization and cellular distribution patterns including proximity to tears, cracks and ruptures, granulation-like tissue, irregularities in collagen fiber orientation, cell clustering and cells with irregular size, shape or organization pattern. Scale bar (in unboxed images) = 50 μm, (in boxed images) = 25 μm. VB = vertebral bone.